Add support for magnetometer Yamaha YAS537

The "hard_offsets" are currently unsigned u8 but they should be signed as they can get negative. They are signed in function yas5xx_meaure_offsets() and in the Yamaha drivers [1][2].

[1] https://github.com/NovaFusion/android_kernel_samsung_golden/blob/cm-12.1/drivers/sensor/compass/yas.h#L156
[2] https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas532.c#L91

Fixes de8860b1ed47 ("iio: magnetometer: Add driver for Yamaha YAS530")

Cc Linus Walleij <[email protected]>

Signed-off-by Jakob Hauser <[email protected]>

Reviewed-by Linus Walleij <[email protected]>

Reviewed-by Andy Shevchenko <[email protected]>

---
 drivers/iio/magnetometer/yamaha-yas530.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/iio/magnetometer/yamaha-yas530.c +1 -1

index b2bc637150bf..40192aa46b04 100644
@@ -132,7 +132,7 @@ struct yas5xx {
 	unsigned int version;
 	char name[16];
 	struct yas5xx_calibration calibration;
-	u8 hard_offsets[3];
+	s8 hard_offsets[3];
 	struct iio_mount_matrix orientation;
 	struct regmap *map;
 	struct regulator_bulk_data regs[2];

Quoted 9 lines · On Sat, 18 Jun 2022 02:13:09 +0200 Jakob Hauser <[email protected]> wrote:

The "hard_offsets" are currently unsigned u8 but they should be signed as they can get negative. They are signed in function yas5xx_meaure_offsets() and in the Yamaha drivers [1][2].

[1] https://github.com/NovaFusion/android_kernel_samsung_golden/blob/cm-12.1/drivers/sensor/compass/yas.h#L156
[2] https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas532.c#L91

Fixes de8860b1ed47 ("iio: magnetometer: Add driver for Yamaha YAS530")

Cc Linus Walleij <[email protected]>

Trivial but it's nice to clean out CC if you also have a tag from the person. All the automation will generally send emails to anyone who has given a tag so the CC doesn't add anything at this point

I try to drop cases of this when applying patches, but if it's done by the submitter it makes my life a little easier!

In function yas5xx_volatile_reg(), the range for measure data should end at "YAS5XX_MEASURE_DATA + 7" instead of "+ 8" as we count from 0 to 7 here.

This change is of low importance as the "+ 8" register isn't called.

Cc Linus Walleij <[email protected]>

Signed-off-by Jakob Hauser <[email protected]>

Reviewed-by Linus Walleij <[email protected]>

Reviewed-by Andy Shevchenko <[email protected]>

---
 drivers/iio/magnetometer/yamaha-yas530.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/iio/magnetometer/yamaha-yas530.c +0 -0

index 40192aa46b04..2799ae0784fd 100644

drivers/iio/magnetometer/yamaha-yas530.c +0 -0

 }
 
 /* TODO: enable regmap cache, using mark dirty and sync at runtime resume */

On Sat, 18 Jun 2022 02:13:10 +0200
Jakob Hauser <[email protected]> wrote:

drivers/iio/magnetometer/yamaha-yas530.c static bool yas5xx_volatile_reg(struct device *dev, unsigned int reg) · line 530

Quoted 4 lines

drivers/iio/magnetometer/yamaha-yas530.c +1 -1

 	return reg == YAS5XX_ACTUATE_INIT_COIL ||
 		reg == YAS5XX_MEASURE ||
-		(reg >= YAS5XX_MEASURE_DATA && reg <= YAS5XX_MEASURE_DATA + 8);
+		(reg >= YAS5XX_MEASURE_DATA && reg <= YAS5XX_MEASURE_DATA + 7);

trivial, but I'd prefer it as
reg < RAS5XX_MEASURE_DATA + 8
because we have 8 registers and do bulk reads of sizeof(u8[8]) so it is more natural to use 8 as the constant.

drivers/iio/magnetometer/yamaha-yas530.c +1 -5

 static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, s32 *zo)
 {
 	struct yas5xx_calibration *c = &yas5xx->calibration;
-	u16 t, x, y1, y2;
+	u16 t_ref, t, x, y1, y2;
 	/* These are "signed x, signed y1 etc */
 	s32 sx, sy1, sy2, sy, sz;
 	int ret;

@@ -329,16 +330,46 @@ static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo,
 	sy1 = yas5xx_linearize(yas5xx, y1, 1);
 	sy2 = yas5xx_linearize(yas5xx, y2, 2);
 
-	/*
-	 * Temperature compensation for x, y1, y2 respectively:
-	 *
-	 *          Cx * t

drivers/iio/magnetometer/yamaha-yas530.c +10 -0

+		break;
+	default:
+		dev_err(yas5xx->dev, "unknown device type\n");
+		return -EINVAL;
+	}
+
+	/* Temperature compensation for x, y1, y2 respectively */
+	if (yas5xx->devid == YAS532_DEVICE_ID &&
+	    yas5xx->version == YAS532_VERSION_AC) {
+		/*

drivers/iio/magnetometer/yamaha-yas530.c +13 -2

+	} else {
+		/*
+		 * YAS530 and YAS532 version AB use solely the t value as a
+		 * multiplier.
+		 *
+		 *          Cx * t
+		 * x' = x - ------
+		 *           100
+		 */
+		sx = sx - (c->Cx * t) / 100;
+		sy1 = sy1 - (c->Cy1 * t) / 100;
+		sy2 = sy2 - (c->Cy2 * t) / 100;
+	}
 
 	/*
 	 * Break y1 and y2 into y and z, y1 and y2 are apparently encoding

@@ -347,11 +378,37 @@ static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo,
 	sy = sy1 - sy2;
 	sz = -sy1 - sy2;
 
-	/*
-	 * FIXME: convert to Celsius? Just guessing this is given

drivers/iio/magnetometer/yamaha-yas530.c +26 -6

+		 *
+		 * Temperature in °C would be (82 / t_ref * t) - 62.
+		 *
+		 * Contrary to this, perform multiplication first and division
+		 * second due to calculating with integers.
+		 *
+		 * To get a nicer result, calculate with 1/10:s degrees Celsius
+		 * and finally multiply by 100 to return milli degrees Celsius.
+		 */
+		*to = ((820 * t / t_ref) - 620) * 100;
+		break;
+	case YAS532_DEVICE_ID:
+		/*
+		 * Actually same procedure for YAS532 but the starting point is
+		 * at -50 °C. Reference value t_ref is the number of counts
+		 * between -50 °C and 20 °C (70 °C range).
+		 */
+		*to = ((700 * t / t_ref) - 500) * 100;
+		break;
+	default:
+		dev_err(yas5xx->dev, "unknown device type\n");
+		return -EINVAL;
+	}
+
 	/*
 	 * Calibrate [x,y,z] with some formulas like this:
 	 *

@@ -384,6 +441,7 @@ static int yas5xx_read_raw(struct iio_dev *indio_dev,
 	int ret;
 
 	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
 	case IIO_CHAN_INFO_RAW:
 		pm_runtime_get_sync(yas5xx->dev);
 		ret = yas5xx_get_measure(yas5xx, &t, &x, &y, &z);

@@ -410,11 +468,6 @@ static int yas5xx_read_raw(struct iio_dev *indio_dev,
 		}
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
-		if (chan->address == 0) {
-			/* Temperature is unscaled */
-			*val = 1;
-			return IIO_VAL_INT;
-		}
 		switch (yas5xx->devid) {
 		case YAS530_DEVICE_ID:
 			/*

@@ -513,7 +566,7 @@ static const struct iio_chan_spec yas5xx_channels[] = {
 		.address = 0,
 		.scan_index = 0,
 		.scan_type = {
-			.sign = 'u',
+			.sign = 's',
 			.realbits = 32,
 			.storagebits = 32,
 			.endianness = IIO_CPU,

On Sat, 18 Jun 2022 02:13:12 +0200
Jakob Hauser <[email protected]> wrote:

Review static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis)

Quoted 3 lines

/* These variant IDs are known from code dumps */
#define YAS537_DEVICE_ID 0x07 /* YAS537 (MS-3T) */

(quoted diff) +0 -0

@@ -314,7 +315,7 @@ static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis)

Hmm. I'm not a great fun of big hydra functions to handle differences between devices. This could easily all be one code flow with some lookups into chip specific constant data (as btw could a lot of the other switch statements in the existing driver).

Quoted 16 lines

drivers/iio/magnetometer/yamaha-yas530.c +1 -5

 static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, s32 *zo)
 {
 	struct yas5xx_calibration *c = &yas5xx->calibration;
-	u16 t, x, y1, y2;
+	u16 t_ref, t, x, y1, y2;
 	/* These are "signed x, signed y1 etc */
 	s32 sx, sy1, sy2, sy, sz;
 	int ret;

@@ -329,16 +330,46 @@ static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo,
 	sy1 = yas5xx_linearize(yas5xx, y1, 1);
 	sy2 = yas5xx_linearize(yas5xx, y2, 2);
 
-	/*
-	 * Temperature compensation for x, y1, y2 respectively:
-	 *
-	 *          Cx * t

drivers/iio/magnetometer/yamaha-yas530.c static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, · line 336

Quoted 10 lines

drivers/iio/magnetometer/yamaha-yas530.c +4 -6

-	 * x' = x - ------
-	 *           100
-	 */
-	sx = sx - (c->Cx * t) / 100;
-	sy1 = sy1 - (c->Cy1 * t) / 100;
-	sy2 = sy2 - (c->Cy2 * t) / 100;
+	/* Set the temperature reference value (unit: counts) */
+	switch (yas5xx->devid) {
+	case YAS530_DEVICE_ID:
+		t_ref = YAS530_20DEGREES;

One thought to simplify the divergent flow below.

		t_ref2 = 0;

drivers/iio/magnetometer/yamaha-yas530.c static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, · line 339

Quoted 3 lines

drivers/iio/magnetometer/yamaha-yas530.c +3 -0

+		break;
+	case YAS532_DEVICE_ID:
+		t_ref = YAS532_20DEGREES;

		if (yas5xx->version == YAS532_VERSION_AC)
			t_ref2 = YAS432_20DEGREES;
		else
			t_ref2 = 0;

Possibly with moving some of the comments below up here. As mentioned below, this stuff would be even better if in a chip type specific const structure rather than as code. That is have one switch statement in probe that picks from an array of

struct yas5xx_chip_info {
	/* COMMENTS ON WHAT these are.. *
	u16 tref;
	u16 tref2;
	int ref_temp_celsius;
	int min_temp_celsuis;
};
static const struct yas5xx_chip_info[] = {
	[ENUM value we will use to pick right on in probe] = {
		...

etc

Quoted 6 lines

drivers/iio/magnetometer/yamaha-yas530.c +0 -2

@@ -347,11 +378,37 @@ static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo,
 	sy = sy1 - sy2;
 	sz = -sy1 - sy2;
 
-	/*
-	 * FIXME: convert to Celsius? Just guessing this is given

drivers/iio/magnetometer/yamaha-yas530.c static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, · line 387

Quoted 10 lines

drivers/iio/magnetometer/yamaha-yas530.c +7 -3

-	 * as 1/10:s of degrees so multiply by 100 to get millicentigrades.
-	 */
-	*to = t * 100;
+	/* Process temperature readout */
+	switch (yas5xx->devid) {
+	case YAS530_DEVICE_ID:
+		/*
+		 * Raw temperature value t is the number of counts starting
+		 * at -62 °C. Reference value t_ref is the number of counts
+		 * between -62 °C and 20 °C (82 °C range).

Roll this info into the maths and only have the constants set in the switch statement. Even better if you just move them into chip specific data so look them up directly rather than via a switch of devid. The whole driver would benefit from moving this stuff to const data rather than switch statements all over the place.

	int min_temp_x10 = yas5xx->chip_info.min_temp_x10;
	const int ref_temp_x10 = 200;

	*to = (min_temp_x10 + ((ref_temp_x10 - min_temp_x10) * t / t_ref)) * 100;

That should make the code self explanatory and remove need for the comments.

Hi Jonathan,

Quoted 3 lines · Jonathan Cameron

On Sat, 18 Jun 2022 02:13:12 +0200
Jakob Hauser <[email protected]> wrote:

...

Quoted 8 lines

Review static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis)

Quoted 3 lines

/* These variant IDs are known from code dumps */
#define YAS537_DEVICE_ID 0x07 /* YAS537 (MS-3T) */

(quoted diff) +0 -0

@@ -314,7 +315,7 @@ static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis)  

Hmm. I'm not a great fun of big hydra functions to handle differences between devices. This could easily all be one code flow with some lookups into chip specific constant data (as btw could a lot of the other switch statements in the existing driver).

I'll try to implement the chip_info approach. This should become a separate patch.

Concerning the patchset, I would prefer to introduce the chip_info approach rather late. That would mean to leave this patch unchanged and introduce your suggestions later within the patchset. I think it's easier to follow the changes along the patchset.

However, you probably would prefer to place the chip_info patch rather early in the patchset?

Quoted 30 lines

Quoted 17 lines

drivers/iio/magnetometer/yamaha-yas530.c +1 -5

 static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, s32 *zo)
 {
 	struct yas5xx_calibration *c = &yas5xx->calibration;
-	u16 t, x, y1, y2;
+	u16 t_ref, t, x, y1, y2;
 	/* These are "signed x, signed y1 etc */
 	s32 sx, sy1, sy2, sy, sz;
 	int ret;

@@ -329,16 +330,46 @@ static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo,
 	sy1 = yas5xx_linearize(yas5xx, y1, 1);
 	sy2 = yas5xx_linearize(yas5xx, y2, 2);
 
-	/*
-	 * Temperature compensation for x, y1, y2 respectively:
-	 *
-	 *          Cx * t

drivers/iio/magnetometer/yamaha-yas530.c static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, · line 336

Quoted 10 lines

drivers/iio/magnetometer/yamaha-yas530.c +4 -6

-	 * x' = x - ------
-	 *           100
-	 */
-	sx = sx - (c->Cx * t) / 100;
-	sy1 = sy1 - (c->Cy1 * t) / 100;
-	sy2 = sy2 - (c->Cy2 * t) / 100;
+	/* Set the temperature reference value (unit: counts) */
+	switch (yas5xx->devid) {
+	case YAS530_DEVICE_ID:
+		t_ref = YAS530_20DEGREES;  

One thought to simplify the divergent flow below.

Quoted 8 lines

		t_ref2 = 0;  

drivers/iio/magnetometer/yamaha-yas530.c static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, · line 339

Quoted 3 lines

drivers/iio/magnetometer/yamaha-yas530.c +3 -0

+		break;
+	case YAS532_DEVICE_ID:
+		t_ref = YAS532_20DEGREES;  

		if (yas5xx->version == YAS532_VERSION_AC)
			t_ref2 = YAS432_20DEGREES;
		else
			t_ref2 = 0;  

The t_ref2 approach looks confusing to me. Because for the most version it's "t_ref2 = 0", only one version out of four needs this.

Another approach: I would rather introduce t_comp (for compensation). In the chip_info, for the most version it would be...

        .t_comp = t,

... and for the one variant it would be:

        .t_comp = t - t_ref,

A problem: I would include the YAS variants like YAS530, YAS532 etc. in the chip_info. The versions like "AB" and "AC", on the other hand, I wouldn't include into the chip_info, instead I would handle these in the functions. In that case the, "t_comp" thing would need to be done in the function using an if statement, similar to what you suggested up here.

This is a preparation for adding YAS537 variant.

YAS537 uses other data types on the calibration coefficients [1] than YAS530 [2] and YAS532 [3].

On YAS537, at least for a4 and a7 this could matter because 8-bit unsigned data from the register gets stored into a signed data type, therefore this should be 8-bit as well.

For YAS530/532, on the other hand, it doesn't seem to matter. The size of a2-a9 and k is smaller than 8-bit at extraction, also the applied math is low. And Cx/Cy1/Cy2, now being defined as signed 16-bit, are extracted as unsigned 8-bit and undergo only minor math.

[1] https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas537.c#L76-L78
[2] https://github.com/NovaFusion/android_kernel_samsung_golden/blob/cm-12.1/drivers/sensor/compass/yas_mag_driver-yas530.c#L526-L527
[3] https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas532.c#L76-L77

Cc Linus Walleij <[email protected]>

Signed-off-by Jakob Hauser <[email protected]>

Reviewed-by Linus Walleij <[email protected]>

Reviewed-by Andy Shevchenko <[email protected]>

---
 drivers/iio/magnetometer/yamaha-yas530.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

drivers/iio/magnetometer/yamaha-yas530.c +4 -2

index 9b45a550f31e..c6f5f25793c4 100644
@@ -103,9 +103,11 @@ struct yas5xx_calibration {
 	s32 r[3];
 	u32 f[3];
 	/* Temperature compensation calibration */
-	s32 Cx, Cy1, Cy2;
+	s16 Cx, Cy1, Cy2;
 	/* Misc calibration coefficients */
-	s32 a2, a3, a4, a5, a6, a7, a8, a9, k;
+	s8  a2, a3, a4, a6, a7, a8;
+	s16 a5, a9;
+	u8  k;
 	/* clock divider */
 	u8 dck;
 };

Quoted 9 lines · On Sat, 18 Jun 2022 02:13:13 +0200 Jakob Hauser <[email protected]> wrote:

This is a preparation for adding YAS537 variant.

YAS537 uses other data types on the calibration coefficients [1] than YAS530 [2] and YAS532 [3].

On YAS537, at least for a4 and a7 this could matter because 8-bit unsigned data from the register gets stored into a signed data type, therefore this should be 8-bit as well.

Quoted 4 lines

For YAS530/532, on the other hand, it doesn't seem to matter. The size of a2-a9 and k is smaller than 8-bit at extraction, also the applied math is low. And Cx/Cy1/Cy2, now being defined as signed 16-bit, are extracted as unsigned 8-bit and undergo only minor math.

Ok. If this is harmless to existing drivers fair enough, though my personal inclination would have been to take the easier approach of making the new variant sign extend on variable load (sign_extend_32() and similar) just so we didn't need to check the older parts weren't affected.

Quoted 7 lines · Jonathan Cameron

On Sat, 18 Jun 2022 02:13:13 +0200
Jakob Hauser <[email protected]> wrote:

Ok. If this is harmless to existing drivers fair enough, though my personal inclination would have been to take the easier approach of making the new variant sign extend on variable load (sign_extend_32() and similar) just so we didn't need to check the older parts weren't affected.

I didn't know that operation :) Let's take this.

Not sure how to handle the "Reviewed-by:" tags. Even though it's a small patch, it gets modified a lot. Therefore I'd remove the tags of Linus and Andy.

Quoted 17 lines · Jonathan Cameron

Quoted 13 lines · On Sat, 18 Jun 2022 02:13:13 +0200 Jakob Hauser <[email protected]> wrote:

This is a preparation for adding YAS537 variant.

YAS537 uses other data types on the calibration coefficients [1] than YAS530 [2] and YAS532 [3].

On YAS537, at least for a4 and a7 this could matter because 8-bit unsigned data from the register gets stored into a signed data type, therefore this should be 8-bit as well.

For YAS530/532, on the other hand, it doesn't seem to matter. The size of a2-a9 and k is smaller than 8-bit at extraction, also the applied math is low. And Cx/Cy1/Cy2, now being defined as signed 16-bit, are extracted as unsigned 8-bit and undergo only minor math.

Quoted 4 lines

Ok. If this is harmless to existing drivers fair enough, though my personal inclination would have been to take the easier approach of making the new variant sign extend on variable load (sign_extend_32() and similar) just so we didn't need to check the older parts weren't affected.

I didn't know that operation :) Let's take this.

This is a preparation for adding YAS537 variant.

Rename functions used only by YAS530 & YAS532 from yas5xx to yas530_532.

Same for the registers.

Cc Linus Walleij <[email protected]>

Signed-off-by Jakob Hauser <[email protected]>

Reviewed-by Linus Walleij <[email protected]>

Reviewed-by Andy Shevchenko <[email protected]>

---
 drivers/iio/magnetometer/yamaha-yas530.c | 106 ++++++++++++-----------
 1 file changed, 55 insertions(+), 51 deletions(-)

drivers/iio/magnetometer/yamaha-yas530.c +1 -5

index c6f5f25793c4..98c8d365fab7 100644
@@ -40,20 +40,22 @@
 
 #include <asm/unaligned.h>
 
-/* This register map covers YAS530 and YAS532 but differs in YAS 537 and YAS539 */
+/* Commonly used registers */
 #define YAS5XX_DEVICE_ID		0x80
-#define YAS5XX_ACTUATE_INIT_COIL	0x81
-#define YAS5XX_MEASURE			0x82
-#define YAS5XX_CONFIG			0x83
-#define YAS5XX_MEASURE_INTERVAL		0x84

drivers/iio/magnetometer/yamaha-yas530.c +11 -1

+#define YAS530_532_MEASURE		0x82
+#define YAS530_532_CONFIG		0x83
+#define YAS530_532_MEASURE_INTERVAL	0x84
+#define YAS530_532_OFFSET_X		0x85 /* [-31 .. 31] */
+#define YAS530_532_OFFSET_Y1		0x86 /* [-31 .. 31] */
+#define YAS530_532_OFFSET_Y2		0x87 /* [-31 .. 31] */
+#define YAS530_532_TEST1		0x88
+#define YAS530_532_TEST2		0x89
+#define YAS530_532_CAL			0x90
+
 /* Bits in the YAS5xx config register */
 #define YAS5XX_CONFIG_INTON		BIT(0) /* Interrupt on? */
 #define YAS5XX_CONFIG_INTHACT		BIT(1) /* Interrupt active high? */

@@ -182,7 +184,7 @@ static u16 yas532_extract_axis(u8 *data)
 }
 
 /**
- * yas5xx_measure() - Make a measure from the hardware
+ * yas530_532_measure() - Make a measure from the hardware
  * @yas5xx: The device state
  * @t: the raw temperature measurement
  * @x: the raw x axis measurement

drivers/iio/magnetometer/yamaha-yas530.c +40 -38

+			      u16 *x, u16 *y1, u16 *y2)
 {
 	unsigned int busy;
 	u8 data[8];

@@ -198,7 +201,7 @@ static int yas5xx_measure(struct yas5xx *yas5xx, u16 *t, u16 *x, u16 *y1, u16 *y
 	u16 val;
 
 	mutex_lock(&yas5xx->lock);
-	ret = regmap_write(yas5xx->map, YAS5XX_MEASURE, YAS5XX_MEASURE_START);
+	ret = regmap_write(yas5xx->map, YAS530_532_MEASURE, YAS5XX_MEASURE_START);
 	if (ret < 0)
 		goto out_unlock;
 

@@ -264,7 +267,7 @@ static int yas5xx_measure(struct yas5xx *yas5xx, u16 *t, u16 *x, u16 *y1, u16 *y
 	return ret;
 }
 
-static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis)
+static s32 yas530_532_linearize(struct yas5xx *yas5xx, u16 val, int axis)
 {
 	struct yas5xx_calibration *c = &yas5xx->calibration;
 	static const s32 yas532ac_coef[] = {

@@ -306,7 +309,7 @@ static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis)
 }
 
 /**
- * yas5xx_get_measure() - Measure a sample of all axis and process
+ * yas530_532_get_measure() - Measure a sample of all axis and process
  * @yas5xx: The device state
  * @to: Temperature out
  * @xo: X axis out

@@ -314,7 +317,8 @@ static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis)
  * @zo: Z axis out
  * @return: 0 on success or error code
  */
-static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, s32 *zo)
+static int yas530_532_get_measure(struct yas5xx *yas5xx, s32 *to,
+				  s32 *xo, s32 *yo, s32 *zo)
 {
 	struct yas5xx_calibration *c = &yas5xx->calibration;
 	u16 t_ref, t, x, y1, y2;

@@ -323,14 +327,14 @@ static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo,
 	int ret;
 
 	/* We first get raw data that needs to be translated to [x,y,z] */
-	ret = yas5xx_measure(yas5xx, &t, &x, &y1, &y2);
+	ret = yas530_532_measure(yas5xx, &t, &x, &y1, &y2);
 	if (ret)
 		return ret;
 
 	/* Do some linearization if available */
-	sx = yas5xx_linearize(yas5xx, x, 0);
-	sy1 = yas5xx_linearize(yas5xx, y1, 1);
-	sy2 = yas5xx_linearize(yas5xx, y2, 2);
+	sx = yas530_532_linearize(yas5xx, x, 0);
+	sy1 = yas530_532_linearize(yas5xx, y1, 1);
+	sy2 = yas530_532_linearize(yas5xx, y2, 2);
 
 	/* Set the temperature reference value (unit: counts) */
 	switch (yas5xx->devid) {

@@ -602,11 +606,11 @@ static const struct regmap_config yas5xx_regmap_config = {
 };
 
 /**
- * yas53x_extract_calibration() - extracts the a2-a9 and k calibration
+ * yas530_532_extract_calibration() - extracts the a2-a9 and k calibration
  * @data: the bitfield to use
  * @c: the calibration to populate
  */
-static void yas53x_extract_calibration(u8 *data, struct yas5xx_calibration *c)
+static void yas530_532_extract_calibration(u8 *data, struct yas5xx_calibration *c)
 {
 	u64 val = get_unaligned_be64(data);
 

@@ -644,12 +648,12 @@ static int yas530_get_calibration_data(struct yas5xx *yas5xx)
 	int ret;
 
 	/* Dummy read, first read is ALWAYS wrong */
-	ret = regmap_bulk_read(yas5xx->map, YAS5XX_CAL, data, sizeof(data));
+	ret = regmap_bulk_read(yas5xx->map, YAS530_532_CAL, data, sizeof(data));
 	if (ret)
 		return ret;
 
 	/* Actual calibration readout */
-	ret = regmap_bulk_read(yas5xx->map, YAS5XX_CAL, data, sizeof(data));
+	ret = regmap_bulk_read(yas5xx->map, YAS530_532_CAL, data, sizeof(data));
 	if (ret)
 		return ret;
 	dev_dbg(yas5xx->dev, "calibration data: %*ph\n", 14, data);

@@ -661,7 +665,7 @@ static int yas530_get_calibration_data(struct yas5xx *yas5xx)
 	c->Cx = data[0] * 6 - 768;
 	c->Cy1 = data[1] * 6 - 768;
 	c->Cy2 = data[2] * 6 - 768;
-	yas53x_extract_calibration(&data[3], c);
+	yas530_532_extract_calibration(&data[3], c);
 
 	/*
 	 * Extract linearization:

@@ -692,11 +696,11 @@ static int yas532_get_calibration_data(struct yas5xx *yas5xx)
 	int ret;
 
 	/* Dummy read, first read is ALWAYS wrong */
-	ret = regmap_bulk_read(yas5xx->map, YAS5XX_CAL, data, sizeof(data));
+	ret = regmap_bulk_read(yas5xx->map, YAS530_532_CAL, data, sizeof(data));
 	if (ret)
 		return ret;
 	/* Actual calibration readout */
-	ret = regmap_bulk_read(yas5xx->map, YAS5XX_CAL, data, sizeof(data));
+	ret = regmap_bulk_read(yas5xx->map, YAS530_532_CAL, data, sizeof(data));
 	if (ret)
 		return ret;
 	dev_dbg(yas5xx->dev, "calibration data: %*ph\n", 14, data);

@@ -715,7 +719,7 @@ static int yas532_get_calibration_data(struct yas5xx *yas5xx)
 	c->Cx = data[0] * 10 - 1280;
 	c->Cy1 = data[1] * 10 - 1280;
 	c->Cy2 = data[2] * 10 - 1280;
-	yas53x_extract_calibration(&data[3], c);
+	yas530_532_extract_calibration(&data[3], c);
 	/*
 	 * Extract linearization:
 	 * Linearization layout in the 32 bits at byte 10:

@@ -738,7 +742,7 @@ static int yas532_get_calibration_data(struct yas5xx *yas5xx)
 	return 0;
 }
 
-static void yas5xx_dump_calibration(struct yas5xx *yas5xx)
+static void yas530_532_dump_calibration(struct yas5xx *yas5xx)
 {
 	struct yas5xx_calibration *c = &yas5xx->calibration;
 

@@ -761,20 +765,20 @@ static void yas5xx_dump_calibration(struct yas5xx *yas5xx)
 	dev_dbg(yas5xx->dev, "dck = %d\n", c->dck);
 }
 
-static int yas5xx_set_offsets(struct yas5xx *yas5xx, s8 ox, s8 oy1, s8 oy2)
+static int yas530_532_set_offsets(struct yas5xx *yas5xx, s8 ox, s8 oy1, s8 oy2)
 {
 	int ret;
 
-	ret = regmap_write(yas5xx->map, YAS5XX_OFFSET_X, ox);
+	ret = regmap_write(yas5xx->map, YAS530_532_OFFSET_X, ox);
 	if (ret)
 		return ret;
-	ret = regmap_write(yas5xx->map, YAS5XX_OFFSET_Y1, oy1);
+	ret = regmap_write(yas5xx->map, YAS530_532_OFFSET_Y1, oy1);
 	if (ret)
 		return ret;
-	return regmap_write(yas5xx->map, YAS5XX_OFFSET_Y2, oy2);
+	return regmap_write(yas5xx->map, YAS530_532_OFFSET_Y2, oy2);
 }
 
-static s8 yas5xx_adjust_offset(s8 old, int bit, u16 center, u16 measure)
+static s8 yas530_532_adjust_offset(s8 old, int bit, u16 center, u16 measure)
 {
 	if (measure > center)
 		return old + BIT(bit);

@@ -783,7 +787,7 @@ static s8 yas5xx_adjust_offset(s8 old, int bit, u16 center, u16 measure)
 	return old;
 }
 
-static int yas5xx_meaure_offsets(struct yas5xx *yas5xx)
+static int yas530_532_measure_offsets(struct yas5xx *yas5xx)
 {
 	int ret;
 	u16 center;

@@ -792,7 +796,7 @@ static int yas5xx_meaure_offsets(struct yas5xx *yas5xx)
 	int i;
 
 	/* Actuate the init coil and measure offsets */
-	ret = regmap_write(yas5xx->map, YAS5XX_ACTUATE_INIT_COIL, 0);
+	ret = regmap_write(yas5xx->map, YAS530_532_ACTUATE_INIT_COIL, 0);
 	if (ret)
 		return ret;
 

@@ -826,26 +830,26 @@ static int yas5xx_meaure_offsets(struct yas5xx *yas5xx)
 	oy2 = 0;
 
 	for (i = 4; i >= 0; i--) {
-		ret = yas5xx_set_offsets(yas5xx, ox, oy1, oy2);
+		ret = yas530_532_set_offsets(yas5xx, ox, oy1, oy2);
 		if (ret)
 			return ret;
 
-		ret = yas5xx_measure(yas5xx, &t, &x, &y1, &y2);
+		ret = yas530_532_measure(yas5xx, &t, &x, &y1, &y2);
 		if (ret)
 			return ret;
 		dev_dbg(yas5xx->dev, "measurement %d: x=%d, y1=%d, y2=%d\n",
 			5-i, x, y1, y2);
 
-		ox = yas5xx_adjust_offset(ox, i, center, x);
-		oy1 = yas5xx_adjust_offset(oy1, i, center, y1);
-		oy2 = yas5xx_adjust_offset(oy2, i, center, y2);
+		ox = yas530_532_adjust_offset(ox, i, center, x);
+		oy1 = yas530_532_adjust_offset(oy1, i, center, y1);
+		oy2 = yas530_532_adjust_offset(oy2, i, center, y2);
 	}
 
 	/* Needed for calibration algorithm */
 	yas5xx->hard_offsets[0] = ox;
 	yas5xx->hard_offsets[1] = oy1;
 	yas5xx->hard_offsets[2] = oy2;
-	ret = yas5xx_set_offsets(yas5xx, ox, oy1, oy2);
+	ret = yas530_532_set_offsets(yas5xx, ox, oy1, oy2);
 	if (ret)
 		return ret;
 

@@ -854,27 +858,27 @@ static int yas5xx_meaure_offsets(struct yas5xx *yas5xx)
 	return 0;
 }
 
-static int yas5xx_power_on(struct yas5xx *yas5xx)
+static int yas530_532_power_on(struct yas5xx *yas5xx)
 {
 	unsigned int val;
 	int ret;
 
 	/* Zero the test registers */
-	ret = regmap_write(yas5xx->map, YAS5XX_TEST1, 0);
+	ret = regmap_write(yas5xx->map, YAS530_532_TEST1, 0);
 	if (ret)
 		return ret;
-	ret = regmap_write(yas5xx->map, YAS5XX_TEST2, 0);
+	ret = regmap_write(yas5xx->map, YAS530_532_TEST2, 0);
 	if (ret)
 		return ret;
 
 	/* Set up for no interrupts, calibrated clock divider */
 	val = FIELD_PREP(YAS5XX_CONFIG_CCK_MASK, yas5xx->calibration.dck);
-	ret = regmap_write(yas5xx->map, YAS5XX_CONFIG, val);
+	ret = regmap_write(yas5xx->map, YAS530_532_CONFIG, val);
 	if (ret)
 		return ret;
 
 	/* Measure interval 0 (back-to-back?)  */
-	return regmap_write(yas5xx->map, YAS5XX_MEASURE_INTERVAL, 0);
+	return regmap_write(yas5xx->map, YAS530_532_MEASURE_INTERVAL, 0);
 }
 
 static int yas5xx_probe(struct i2c_client *i2c,

@@ -956,11 +960,11 @@ static int yas5xx_probe(struct i2c_client *i2c,
 		goto assert_reset;
 	}
 
-	yas5xx_dump_calibration(yas5xx);
-	ret = yas5xx_power_on(yas5xx);
+	yas530_532_dump_calibration(yas5xx);
+	ret = yas530_532_power_on(yas5xx);
 	if (ret)
 		goto assert_reset;
-	ret = yas5xx_meaure_offsets(yas5xx);
+	ret = yas530_532_measure_offsets(yas5xx);
 	if (ret)
 		goto assert_reset;
 

Quoted 3 lines · On Sat, 18 Jun 2022 02:13:14 +0200 Jakob Hauser <[email protected]> wrote:

This is a preparation for adding YAS537 variant.

Rename functions used only by YAS530 & YAS532 from yas5xx to yas530_532.

We've been bitten in the past by naming choices like this, so please use yas530 only and rely on comments or code that makes it obvious that it applies to the yas532 as well.

On 18.06.22 17:00, Jonathan Cameron wrote:

Again I'm not sure on the "Reviewed-by:" tags. Again the patch gets modified a lot, therefore I would remove the tags.

Hi Jonathan,

Quoted 11 lines · Jonathan Cameron

Quoted 3 lines · On Sat, 18 Jun 2022 02:13:14 +0200 Jakob Hauser <[email protected]> wrote:

This is a preparation for adding YAS537 variant.

Rename functions used only by YAS530 & YAS532 from yas5xx to yas530_532.

We've been bitten in the past by naming choices like this, so please use yas530 only and rely on comments or code that makes it obvious that it applies to the yas532 as well.

Hm, ok. It's harder to keep the overview. But I can imagine adding up names can get out of control. I'll change it.

For functions and registers used by all variants, I'd keep yas5xx or YAS5XX respectively. I hope that's ok.

Again I'm not sure on the "Reviewed-by:" tags. Again the patch gets modified a lot, therefore I would remove the tags.

...

Kind regards,
Jakob

Quoted 9 lines · On Tue, 21 Jun 2022 02:53:58 +0200 Jakob Hauser <[email protected]> wrote:

Quoted 4 lines · Jonathan Cameron

We've been bitten in the past by naming choices like this, so please use yas530 only and rely on comments or code that makes it obvious that it applies to the yas532 as well.

Hm, ok. It's harder to keep the overview. But I can imagine adding up names can get out of control. I'll change it.

Quoted 2 lines

For functions and registers used by all variants, I'd keep yas5xx or YAS5XX respectively. I hope that's ok.

I reserve the right to laugh at you if the next variant to come along fits the wild card but not the registers that have been shared until then :)

Otherwise, I'm fine with keeping the naming for those cases.

This commit gathers minor cleanups in the current driver.

In the device examples, "Xiaomi" is too generic, specific devices should be listed here. E.g. Xiaomi Redmi 2 seems to have YAS537 but it's not fully clear if this applies to all its variants. Samsung Galaxy S7 is often quoted in conjunction with YAS537.

In the function yas530_get_calibration_data(), the debug dump was extended to 16 elements as this is the size of the calibration data array of YAS530.

Quoted 8 lines · Jakob Hauser

This commit gathers minor cleanups in the current driver.

In the device examples, "Xiaomi" is too generic, specific devices should be listed here. E.g. Xiaomi Redmi 2 seems to have YAS537 but it's not fully clear if this applies to all its variants. Samsung Galaxy S7 is often quoted in conjunction with YAS537.

Quoted 2 lines

In the function yas530_get_calibration_data(), the debug dump was extended to 16 elements as this is the size of the calibration data array of YAS530.

We do not accept or even consider contributions w/o SoB tag, sorry.

P.S. Reading briefly, split this to two patches:
1) moving %*ph parameters out from stack;
2) documentation and indentation fixes.

This adds support for the magnetometer Yamaha YAS537. The additions are based on comparison of Yamaha Android kernel drivers for YAS532 [1] and YAS537 [2].

In the Yamaha YAS537 Android driver, there is an overflow/underflow control implemented. For regular usage, this seems not necessary. A similar overflow/ underflow control of Yamaha YAS530/532 Android driver isn't integrated in the mainline driver. It is therefore skipped for YAS537 in mainline too.

Also in the Yamaha YAS537 Android driver, at the end of the reset_yas537() function, a measurement is saved in "last_after_rcoil". Later on, this is compared to current measurements. If the difference gets too big, a new reset is initialized. The difference in measurements needs to be quite big, it's hard to say if this is necessary for regular operation. Therefore this isn't integrated in the mainline driver either.

-/* These variant IDs are known from code dumps */

        case IIO_CHAN_INFO_RAW:
                pm_runtime_get_sync(yas5xx->dev);

drivers/iio/magnetometer/yamaha-yas530.c +2 -1

-               ret = yas5xx_get_measure(yas5xx, &t, &x, &y, &z);
+               switch (yas5xx->devid) {
+               case YAS530_DEVICE_ID:

+ }

                pm_runtime_mark_last_busy(yas5xx->dev);
                pm_runtime_put_autosuspend(yas5xx->dev);

+ }

        pm_runtime_mark_last_busy(yas5xx->dev);
        pm_runtime_put_autosuspend(yas5xx->dev);

drivers/iio/magnetometer/yamaha-yas530.c +6 -0

+       switch (yas5xx->devid) {
+       case YAS530_DEVICE_ID:
+       case YAS532_DEVICE_ID:
+               if (reg == YAS530_532_ACTUATE_INIT_COIL ||
+                   reg == YAS530_532_MEASURE)
+                       return true;

drivers/iio/magnetometer/yamaha-yas530.c +3 -0

+       }
+
+       return false;

+ /* Writing SRST register, the exact meaning is unknown */

drivers/iio/magnetometer/yamaha-yas530.c +15 -0

+               /*
+                * The first version simply writes data back into registers:
+                *
+                * data[0]  YAS537_MTC          0x93
+                * data[1]                      0x94
+                * data[2]                      0x95
+                * data[3]                      0x96
+                * data[4]                      0x97
+                * data[5]                      0x98
+                * data[6]                      0x99
+                * data[7]                      0x9a
+                * data[8]                      0x9b
+                * data[9]                      0x9c
+                * data[10]                     0x9d
+                * data[11] YAS537_OC           0x9e

drivers/iio/magnetometer/yamaha-yas530.c +16 -0

+               for (i = 0; i < 17; i++) {
+                       if (i < 12) {
+                               ret = regmap_write(yas5xx->map,
+                                                  YAS537_MTC + i,
+                                                  data[i]);
+                               if (ret)
+                                       return ret;
+                       } else if (i < 15) {
+                               ret = regmap_write(yas5xx->map,
+                                                  YAS537_OFFSET_X + i - 12,
+                                                  data[i]);
+                               if (ret)
+                                       return ret;
+                               yas5xx->hard_offsets[i - 12] = data[i];
+                       } else {
+                               ret = regmap_write(yas5xx->map,

+ case YAS537_VERSION_1:

+ }

- strncpy(yas5xx->name, "yas530", sizeof(yas5xx->name));

                break;

+
default:

Quoted 2 lines · Jakob Hauser

-/* These variant IDs are known from code dumps */

Not sure why this change
a) is here (means maybe you need to move the comment somewhere else?);
b) done at all (means maybe this comment is still actual?).

Quoted 14 lines

drivers/iio/magnetometer/yamaha-yas530.c +14 -0

+       switch (yas5xx->devid) {
+       case YAS530_DEVICE_ID:
+       case YAS532_DEVICE_ID:
+               if (reg == YAS530_532_ACTUATE_INIT_COIL ||
+                   reg == YAS530_532_MEASURE)
+                       return true;
+               break;
+       case YAS537_DEVICE_ID:
+               if (reg == YAS537_MEASURE)
+                       return true;
+               break;
+       default:
+               dev_err(yas5xx->dev, "unknown device type\n");
+               break;

Quoted 1 line

+ /* fall through */

What does this mean?

It seems here you may actually to return directly.

Quoted 1 line

+ /* Writing SRST register, the exact meaning is unknown */

Wild guess: Software ReSeT (SRST). Would explain why it should be done before calibration.

drivers/iio/magnetometer/yamaha-yas530.c static int yas532_get_calibration_data(struct yas5xx *yas5xx) · line 986

Quoted 3 lines

drivers/iio/magnetometer/yamaha-yas530.c +2 -0

+       case YAS537_VERSION_0:
 
+

Redundant blank line.

Quoted 1 line

- strncpy(yas5xx->name, "yas530", sizeof(yas5xx->name));

Okay, strncpy() -> strscpy() perhaps in the separate patch.

This adds support for the magnetometer Yamaha YAS537. The additions are based on comparison of Yamaha Android kernel drivers for YAS532 [1] and YAS537 [2].

In the Yamaha YAS537 Android driver, there is an overflow/underflow control implemented. For regular usage, this seems not necessary. A similar overflow/ underflow control of Yamaha YAS530/532 Android driver isn't integrated in the mainline driver. It is therefore skipped for YAS537 in mainline too.

Also in the Yamaha YAS537 Android driver, at the end of the reset_yas537() function, a measurement is saved in "last_after_rcoil". Later on, this is compared to current measurements. If the difference gets too big, a new reset is initialized. The difference in measurements needs to be quite big, it's hard to say if this is necessary for regular operation. Therefore this isn't integrated in the mainline driver either.

[1] https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas532.c
[2] https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas537.c

Cc Linus Walleij <[email protected]>

Signed-off-by Jakob Hauser <[email protected]>

Reviewed-by Linus Walleij <[email protected]>

---
The diff on function yas5xx_probe() is a bit confusing. Maybe better to
understand when comparing before and after code.
before: https://github.com/torvalds/linux/blob/v5.19-rc2/drivers/iio/magnetometer/yamaha-yas530.c#L873-L902
after: https://github.com/Jakko3/linux/blob/yas537_v3/drivers/iio/magnetometer/yamaha-yas530.c#L1416-L1463

 drivers/iio/magnetometer/Kconfig         |   4 +-
 drivers/iio/magnetometer/yamaha-yas530.c | 553 +++++++++++++++++++++--
 2 files changed, 529 insertions(+), 28 deletions(-)

drivers/iio/magnetometer/Kconfig +0 -0

index 07eb619bcfe8..868128cee835 100644

drivers/iio/magnetometer/Kconfig +0 -0

 	  This driver can also be compiled as a module.
 	  To compile this driver as a module, choose M here: the module

drivers/iio/magnetometer/yamaha-yas530.c +153 -1

index 72a75dc57e11..e6123d1d9383 100644
@@ -17,6 +17,9 @@
  * named "inv_compass" in the Tegra Android kernel tree.
  * Copyright (C) 2012 InvenSense Corporation
  *
+ * Code functions for YAS537 based on Yamaha Android kernel driver.
+ * Copyright (c) 2014 Yamaha Corporation
+ *
  * Author: Linus Walleij <[email protected]>
  */
 #include <linux/bitfield.h>

@@ -56,6 +59,23 @@
 #define YAS530_532_TEST2		0x89
 #define YAS530_532_CAL			0x90
 
+/* Registers used by YAS537 */
+#define YAS537_MEASURE			0x81 /* Originally YAS537_REG_CMDR */
+#define YAS537_CONFIG			0x82 /* Originally YAS537_REG_CONFR */
+#define YAS537_MEASURE_INTERVAL		0x83 /* Originally YAS537_REG_INTRVLR */
+#define YAS537_OFFSET_X			0x84 /* Originally YAS537_REG_OXR */
+#define YAS537_OFFSET_Y1		0x85 /* Originally YAS537_REG_OY1R */
+#define YAS537_OFFSET_Y2		0x86 /* Originally YAS537_REG_OY2R */
+#define YAS537_AVR			0x87
+#define YAS537_HCK			0x88
+#define YAS537_LCK			0x89
+#define YAS537_SRST			0x90
+#define YAS537_ADCCAL			0x91
+#define YAS537_MTC			0x93
+#define YAS537_OC			0x9E
+#define YAS537_TRM			0x9F
+#define YAS537_CAL			0xC0
+
 /* Bits in the YAS5xx config register */
 #define YAS5XX_CONFIG_INTON		BIT(0) /* Interrupt on? */
 #define YAS5XX_CONFIG_INTHACT		BIT(1) /* Interrupt active high? */

@@ -67,6 +87,7 @@
 #define YAS5XX_MEASURE_LDTC		BIT(1)
 #define YAS5XX_MEASURE_FORS		BIT(2)
 #define YAS5XX_MEASURE_DLYMES		BIT(4)
+#define YAS5XX_MEASURE_CONT		BIT(5)
 
 /* Bits in the measure data register */
 #define YAS5XX_MEASURE_DATA_BUSY	BIT(7)

@@ -93,8 +114,15 @@
 #define YAS532_DATA_OVERFLOW		(BIT(YAS532_DATA_BITS) - 1)
 #define YAS532_20DEGREES		390 /* Counts starting at -50 °C */
 
-/* These variant IDs are known from code dumps */
 #define YAS537_DEVICE_ID		0x07 /* YAS537 (MS-3T) */
+#define YAS537_VERSION_0		0 /* Version naming unknown */
+#define YAS537_VERSION_1		1 /* Version naming unknown */
+#define YAS537_MAG_AVERAGE_32_MASK	GENMASK(6, 4)
+#define YAS537_MEASURE_TIME_WORST_US	1500
+#define YAS537_DEFAULT_SENSOR_DELAY_MS	50
+#define YAS537_MAG_RCOIL_TIME_US	65
+#define YAS537_20DEGREES		8120 /* Counts starting at -386 °C */
+
 #define YAS539_DEVICE_ID		0x08 /* YAS539 (MS-3S) */
 
 /* Turn off device regulators etc after 5 seconds of inactivity */

@@ -267,6 +295,78 @@ static int yas530_532_measure(struct yas5xx *yas5xx, u16 *t,
 	return ret;
 }
 
+/**
+ * yas537_measure() - Make a measure from the hardware
+ * @yas5xx: The device state
+ * @t: the raw temperature measurement
+ * @x: the raw x axis measurement
+ * @y1: the y1 axis measurement
+ * @y2: the y2 axis measurement
+ * @return: 0 on success or error code
+ */
+static int yas537_measure(struct yas5xx *yas5xx, u16 *t,
+			  u16 *x, u16 *y1, u16 *y2)
+{
+	struct yas5xx_calibration *c = &yas5xx->calibration;
+	unsigned int busy;
+	u8 data[8];
+	u16 xy1y2[3];
+	s32 h[3], s[3];
+	int i, ret;
+
+	mutex_lock(&yas5xx->lock);
+
+	/* Contrary to YAS530/532, also a "cont" bit is set, meaning unknown */
+	ret = regmap_write(yas5xx->map, YAS537_MEASURE, YAS5XX_MEASURE_START |
+			   YAS5XX_MEASURE_CONT);
+	if (ret < 0)
+		goto out_unlock;
+
+	/* Use same timeout like YAS530/532 but the bit is in data row 2 */
+	ret = regmap_read_poll_timeout(yas5xx->map, YAS5XX_MEASURE_DATA + 2, busy,
+				       !(busy & YAS5XX_MEASURE_DATA_BUSY),
+				       500, 20000);
+	if (ret) {
+		dev_err(yas5xx->dev, "timeout waiting for measurement\n");
+		goto out_unlock;
+	}
+
+	ret = regmap_bulk_read(yas5xx->map, YAS5XX_MEASURE_DATA,
+			       data, sizeof(data));
+	if (ret)
+		goto out_unlock;
+
+	mutex_unlock(&yas5xx->lock);
+
+	*t = get_unaligned_be16(&data[0]);
+	xy1y2[0] = FIELD_GET(GENMASK(13, 0), get_unaligned_be16(&data[2]));
+	xy1y2[1] = get_unaligned_be16(&data[4]);
+	xy1y2[2] = get_unaligned_be16(&data[6]);
+
+	/* The second version of YAS537 needs to include calibration coefficients */
+	if (yas5xx->version == YAS537_VERSION_1) {
+		for (i = 0; i < 3; i++)
+			s[i] = xy1y2[i] - BIT(13);
+		h[0] = (c->k *   (128 * s[0] + c->a2 * s[1] + c->a3 * s[2])) / BIT(13);
+		h[1] = (c->k * (c->a4 * s[0] + c->a5 * s[1] + c->a6 * s[2])) / BIT(13);
+		h[2] = (c->k * (c->a7 * s[0] + c->a8 * s[1] + c->a9 * s[2])) / BIT(13);
+		for (i = 0; i < 3; i++) {
+			clamp_val(h[i], -BIT(13), BIT(13) - 1);
+			xy1y2[i] = h[i] + BIT(13);
+		}
+	}
+
+	*x = xy1y2[0];
+	*y1 = xy1y2[1];
+	*y2 = xy1y2[2];
+
+	return 0;
+
+out_unlock:
+	mutex_unlock(&yas5xx->lock);
+	return ret;
+}
+
 static s32 yas530_532_linearize(struct yas5xx *yas5xx, u16 val, int axis)
 {
 	struct yas5xx_calibration *c = &yas5xx->calibration;

@@ -437,6 +537,58 @@ static int yas530_532_get_measure(struct yas5xx *yas5xx, s32 *to,
 	return 0;
 }
 
+/**
+ * yas537_get_measure() - Measure a sample of all axis and process
+ * @yas5xx: The device state
+ * @to: Temperature out
+ * @xo: X axis out
+ * @yo: Y axis out
+ * @zo: Z axis out
+ * @return: 0 on success or error code
+ */
+static int yas537_get_measure(struct yas5xx *yas5xx, s32 *to,
+			      s32 *xo, s32 *yo, s32 *zo)
+{
+	u16 t_ref, t, x, y1, y2;
+	int ret;
+
+	/* We first get raw data that needs to be translated to [x,y,z] */
+	ret = yas537_measure(yas5xx, &t, &x, &y1, &y2);
+	if (ret)
+		return ret;
+
+	/* Set the temperature reference value (unit: counts) */
+	t_ref = YAS537_20DEGREES;
+
+	/*
+	 * Raw temperature value t is the number of counts. YAS537 product
+	 * description No. PBAS537A-000-01-e mentions a temperature resolution
+	 * of 0.05 °C/count. A readout of the t value at ca. 20 °C returns
+	 * approx. 8120 counts.
+	 *
+	 * 8120 counts x 0.05 °C/count corresponds to a range of 406 °C.
+	 * 0 counts would be at theoretical -386 °C.
+	 *
+	 * The formula used for YAS530/532 needs to be adapted to this
+	 * theoretical starting temperature, again calculating with 1/10:s
+	 * of degrees Celsius and finally multiplying by 100 to get milli
+	 * degrees Celsius.
+	 */
+	*to = ((4060 * t / t_ref) - 3860) * 100;
+
+	/*
+	 * Unfortunately, no linearization or temperature compensation formulas
+	 * are known for YAS537.
+	 */
+
+	/* Calculate x, y, z from x, y1, y2 */
+	*xo = (x - BIT(13)) * 300;
+	*yo = (y1 - y2) * 1732 / 10;
+	*zo = (-y1 - y2 + BIT(14)) * 300;
+
+	return 0;
+}
+
 static int yas5xx_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val, int *val2,

drivers/iio/magnetometer/yamaha-yas530.c +11 -2

+			break;
+		case YAS537_DEVICE_ID:
+			ret = yas537_get_measure(yas5xx, &t, &x, &y, &z);
+			break;
+		default:
+			dev_err(yas5xx->dev, "unknown device type\n");
+			return -EINVAL;
+		}
 		pm_runtime_mark_last_busy(yas5xx->dev);
 		pm_runtime_put_autosuspend(yas5xx->dev);
 		if (ret)

@@ -484,9 +647,10 @@ static int yas5xx_read_raw(struct iio_dev *indio_dev,
 			*val2 = 100000000;
 			break;
 		case YAS532_DEVICE_ID:
+		case YAS537_DEVICE_ID:
 			/*
-			 * Raw values of YAS532 are in nanotesla. Divide by
-			 * 100000 (10^5) to get Gauss.
+			 * Raw values of YAS532 and YAS537 are in nanotesla.
+			 * Divide by 100000 (10^5) to get Gauss.
 			 */
 			*val = 1;
 			*val2 = 100000;

drivers/iio/magnetometer/yamaha-yas530.c +12 -2

+	switch (yas5xx->devid) {
+	case YAS530_DEVICE_ID:
+	case YAS532_DEVICE_ID:
+		ret = yas530_532_get_measure(yas5xx, &t, &x, &y, &z);
+		break;
+	case YAS537_DEVICE_ID:
+		ret = yas537_get_measure(yas5xx, &t, &x, &y, &z);
+		break;
+	default:
+		dev_err(yas5xx->dev, "unknown device type\n");
+		return;
+	}
 	pm_runtime_mark_last_busy(yas5xx->dev);
 	pm_runtime_put_autosuspend(yas5xx->dev);
 	if (ret) {

@@ -592,9 +767,34 @@ static const struct iio_info yas5xx_info = {
 
 static bool yas5xx_volatile_reg(struct device *dev, unsigned int reg)
 {
-	return reg == YAS5XX_ACTUATE_INIT_COIL ||
-		reg == YAS5XX_MEASURE ||

drivers/iio/magnetometer/yamaha-yas530.c +43 -0

+	 */
+	switch (yas5xx->devid) {
+	case YAS530_DEVICE_ID:
+	case YAS532_DEVICE_ID:
+		if (reg == YAS530_532_ACTUATE_INIT_COIL ||
+		    reg == YAS530_532_MEASURE)
+			return true;
+		break;
+	case YAS537_DEVICE_ID:
+		if (reg == YAS537_MEASURE)
+			return true;
+		break;
+	default:
+		dev_err(yas5xx->dev, "unknown device type\n");
+		break;
+		/* fall through */
+	}
+
+	return false;
 }
 
 /* TODO: enable regmap cache, using mark dirty and sync at runtime resume */

@@ -749,6 +949,216 @@ static int yas532_get_calibration_data(struct yas5xx *yas5xx)
 	return 0;
 }
 
+static int yas537_get_calibration_data(struct yas5xx *yas5xx)
+{
+	struct yas5xx_calibration *c = &yas5xx->calibration;
+	u8 data[17];
+	u32 val1, val2, val3, val4;
+	int i, ret;
+
+	/* Writing SRST register, the exact meaning is unknown */
+	ret = regmap_write(yas5xx->map, YAS537_SRST, BIT(1));
+	if (ret)
+		return ret;
+
+	/* Calibration readout, YAS537 needs one readout only */
+	ret = regmap_bulk_read(yas5xx->map, YAS537_CAL, data, sizeof(data));
+	if (ret)
+		return ret;
+	dev_dbg(yas5xx->dev, "calibration data: %17ph\n", data);
+
+	/* Sanity check, is this all zeroes? */
+	if (!memchr_inv(data, 0x00, 16)) {
+		if (FIELD_GET(GENMASK(5, 0), data[16]) == 0)
+			dev_warn(yas5xx->dev, "calibration is blank!\n");
+	}
+

drivers/iio/magnetometer/yamaha-yas530.c +16 -0

+
+		/*
+		 * The first version simply writes data back into registers:
+		 *
+		 * data[0]  YAS537_MTC		0x93
+		 * data[1]			0x94
+		 * data[2]			0x95
+		 * data[3]			0x96
+		 * data[4]			0x97
+		 * data[5]			0x98
+		 * data[6]			0x99
+		 * data[7]			0x9a
+		 * data[8]			0x9b
+		 * data[9]			0x9c
+		 * data[10]			0x9d
+		 * data[11] YAS537_OC		0x9e

drivers/iio/magnetometer/yamaha-yas530.c +66 -0

+			if (i < 12) {
+				ret = regmap_write(yas5xx->map,
+						   YAS537_MTC + i,
+						   data[i]);
+				if (ret)
+					return ret;
+			} else if (i < 15) {
+				ret = regmap_write(yas5xx->map,
+						   YAS537_OFFSET_X + i - 12,
+						   data[i]);
+				if (ret)
+					return ret;
+				yas5xx->hard_offsets[i - 12] = data[i];
+			} else {
+				ret = regmap_write(yas5xx->map,
+						   YAS537_HCK + i - 15,
+						   data[i]);
+				if (ret)
+					return ret;
+			}
+		}
+
+		break;
+
+	case YAS537_VERSION_1:
+
+		/*
+		 * The second version writes some data into registers but also
+		 * extracts calibration coefficients.
+		 *
+		 * Registers being written:
+		 *
+		 * data[0]  YAS537_MTC			0x93
+		 * data[1]  YAS537_MTC+1		0x94
+		 * data[2]  YAS537_MTC+2		0x95
+		 * data[3]  YAS537_MTC+3 (partially)	0x96
+		 *
+		 * data[12] YAS537_OFFSET_X		0x84
+		 * data[13] YAS537_OFFSET_Y1		0x85
+		 * data[14] YAS537_OFFSET_Y2		0x86
+		 *
+		 * data[15] YAS537_HCK (partially)	0x88
+		 *          YAS537_LCK (partially)	0x89
+		 * data[16] YAS537_OC  (partially)	0x9e
+		 */
+
+		for (i = 0; i < 3; i++) {
+			ret = regmap_write(yas5xx->map, YAS537_MTC + i,
+					   data[i]);
+			if (ret)
+				return ret;
+			ret = regmap_write(yas5xx->map, YAS537_OFFSET_X + i,
+					   data[i + 12]);
+			if (ret)
+				return ret;
+			yas5xx->hard_offsets[i] = data[i + 12];
+		}
+
+		/*
+		 * Visualization of partially taken data:
+		 *
+		 * data[3]       n 7 6 5 4 3 2 1 0
+		 * YAS537_MTC+3    x x x 1 0 0 0 0
+		 *
+		 * data[15]      n 7 6 5 4 3 2 1 0
+		 * YAS537_HCK      x x x x 0

drivers/iio/magnetometer/yamaha-yas530.c +90 -0

+		if (ret)
+			return ret;
+		ret = regmap_write(yas5xx->map, YAS537_LCK,
+				   FIELD_GET(GENMASK(3, 0), data[15]) << 1);
+		if (ret)
+			return ret;
+		ret = regmap_write(yas5xx->map, YAS537_OC,
+				   FIELD_GET(GENMASK(5, 0), data[16]));
+		if (ret)
+			return ret;
+
+		/*
+		 * For data extraction, build some blocks. Four 32-bit blocks
+		 * look appropriate.
+		 *
+		 *            n    7  6  5  4  3  2  1  0
+		 *  data[0]   0 [ Cx Cx Cx Cx Cx Cx Cx Cx ] bits 31 .. 24
+		 *  data[1]   1 [ Cx C1 C1 C1 C1 C1 C1 C1 ] bits 23 .. 16
+		 *  data[2]   2 [ C1 C1 C2 C2 C2 C2 C2 C2 ] bits 15 .. 8
+		 *  data[3]   3 [ C2 C2 C2                ] bits  7 .. 0
+		 *
+		 *            n    7  6  5  4  3  2  1  0
+		 *  data[3]   0 [          a2 a2 a2 a2 a2 ] bits 31 .. 24
+		 *  data[4]   1 [ a2 a2 a3 a3 a3 a3 a3 a3 ] bits 23 .. 16
+		 *  data[5]   2 [ a3 a4 a4 a4 a4 a4 a4 a4 ] bits 15 .. 8
+		 *  data[6]   3 [ a4                      ] bits  7 .. 0
+		 *
+		 *            n    7  6  5  4  3  2  1  0
+		 *  data[6]   0 [    a5 a5 a5 a5 a5 a5 a5 ] bits 31 .. 24
+		 *  data[7]   1 [ a5 a5 a6 a6 a6 a6 a6 a6 ] bits 23 .. 16
+		 *  data[8]   2 [ a6 a7 a7 a7 a7 a7 a7 a7 ] bits 15 .. 8
+		 *  data[9]   3 [ a7                      ] bits  7 .. 0
+		 *
+		 *            n    7  6  5  4  3  2  1  0
+		 *  data[9]   0 [    a8 a8 a8 a8 a8 a8 a8 ] bits 31 .. 24
+		 *  data[10]  1 [ a9 a9 a9 a9 a9 a9 a9 a9 ] bits 23 .. 16
+		 *  data[11]  2 [ a9  k  k  k  k  k  k  k ] bits 15 .. 8
+		 *  data[12]  3 [                         ] bits  7 .. 0
+		 */
+
+		/* Get data into these four blocks val1 to val4 */
+		val1 = get_unaligned_be32(&data[0]);
+		val2 = get_unaligned_be32(&data[3]);
+		val3 = get_unaligned_be32(&data[6]);
+		val4 = get_unaligned_be32(&data[9]);
+
+		/* Extract calibration coefficients and modify */
+		c->Cx  = FIELD_GET(GENMASK(31, 23), val1) - 256;
+		c->Cy1 = FIELD_GET(GENMASK(22, 14), val1) - 256;
+		c->Cy2 = FIELD_GET(GENMASK(13,  5), val1) - 256;
+		c->a2  = FIELD_GET(GENMASK(28, 22), val2) -  64;
+		c->a3  = FIELD_GET(GENMASK(21, 15), val2) -  64;
+		c->a4  = FIELD_GET(GENMASK(14,  7), val2) - 128;
+		c->a5  = FIELD_GET(GENMASK(30, 22), val3) - 112;
+		c->a6  = FIELD_GET(GENMASK(21, 15), val3) -  64;
+		c->a7  = FIELD_GET(GENMASK(14,  7), val3) - 128;
+		c->a8  = FIELD_GET(GENMASK(30, 24), val4) -  64;
+		c->a9  = FIELD_GET(GENMASK(23, 15), val4) - 112;
+		c->k   = FIELD_GET(GENMASK(14,  8), val4);
+
+		break;
+
+	default:
+		dev_err(yas5xx->dev, "unknown version of YAS537\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static void yas530_532_dump_calibration(struct yas5xx *yas5xx)
 {
 	struct yas5xx_calibration *c = &yas5xx->calibration;

@@ -772,6 +1182,26 @@ static void yas530_532_dump_calibration(struct yas5xx *yas5xx)
 	dev_dbg(yas5xx->dev, "dck = %d\n", c->dck);
 }
 
+static void yas537_dump_calibration(struct yas5xx *yas5xx)
+{
+	struct yas5xx_calibration *c = &yas5xx->calibration;
+
+	if (yas5xx->version == YAS537_VERSION_1) {
+		dev_dbg(yas5xx->dev, "Cx = %d\n", c->Cx);
+		dev_dbg(yas5xx->dev, "Cy1 = %d\n", c->Cy1);
+		dev_dbg(yas5xx->dev, "Cy2 = %d\n", c->Cy2);
+		dev_dbg(yas5xx->dev, "a2 = %d\n", c->a2);
+		dev_dbg(yas5xx->dev, "a3 = %d\n", c->a3);
+		dev_dbg(yas5xx->dev, "a4 = %d\n", c->a4);
+		dev_dbg(yas5xx->dev, "a5 = %d\n", c->a5);
+		dev_dbg(yas5xx->dev, "a6 = %d\n", c->a6);
+		dev_dbg(yas5xx->dev, "a7 = %d\n", c->a7);
+		dev_dbg(yas5xx->dev, "a8 = %d\n", c->a8);
+		dev_dbg(yas5xx->dev, "a9 = %d\n", c->a9);
+		dev_dbg(yas5xx->dev, "k = %d\n", c->k);
+	}
+}
+
 static int yas530_532_set_offsets(struct yas5xx *yas5xx, s8 ox, s8 oy1, s8 oy2)
 {
 	int ret;

@@ -888,6 +1318,45 @@ static int yas530_532_power_on(struct yas5xx *yas5xx)
 	return regmap_write(yas5xx->map, YAS530_532_MEASURE_INTERVAL, 0);
 }
 

drivers/iio/magnetometer/yamaha-yas530.c +22 -0

+	if (ret)
+		return ret;
+	ret = regmap_write(yas5xx->map, YAS537_TRM, GENMASK(7, 0));
+	if (ret)
+		return ret;
+
+	/* The interval value is static in regular operation */
+	intrvl = (YAS537_DEFAULT_SENSOR_DELAY_MS * 1000
+		 - YAS537_MEASURE_TIME_WORST_US) / 4100;
+	ret = regmap_write(yas5xx->map, YAS537_MEASURE_INTERVAL, intrvl);
+	if (ret)
+		return ret;
+
+	/* The average value is also static in regular operation */
+	ret = regmap_write(yas5xx->map, YAS537_AVR, YAS537_MAG_AVERAGE_32_MASK);
+	if (ret)
+		return ret;
+
+	/* Perform the "rcoil" part but skip the "last_after_rcoil" read */
+	ret = regmap_write(yas5xx->map, YAS537_CONFIG, BIT(3));
+	if (ret)
+		return ret;

drivers/iio/magnetometer/yamaha-yas530.c +2 -1

 	switch (yas5xx->devid) {
 	case YAS530_DEVICE_ID:
-		ret = yas530_get_calibration_data(yas5xx);
+	case YAS532_DEVICE_ID:
+

drivers/iio/magnetometer/yamaha-yas530.c +26 -16

+		} else {
+			ret = yas532_get_calibration_data(yas5xx);
+			if (ret)
+				goto assert_reset;
+			dev_info(dev, "detected YAS532/YAS533 MS-3R/F %s",
+				 yas5xx->version ? "AC" : "AB");
+			strncpy(yas5xx->name, "yas532", sizeof(yas5xx->name));
+		}
+
+		yas530_532_dump_calibration(yas5xx);
+		ret = yas530_532_power_on(yas5xx);
+		if (ret)
+			goto assert_reset;
+		ret = yas530_532_measure_offsets(yas5xx);
 		if (ret)
 			goto assert_reset;
-		dev_info(dev, "detected YAS530 MS-3E %s",
-			 yas5xx->version ? "B" : "A");
-		strncpy(yas5xx->name, "yas530", sizeof(yas5xx->name));
 		break;
-	case YAS532_DEVICE_ID:
-		ret = yas532_get_calibration_data(yas5xx);
+
+	case YAS537_DEVICE_ID:
+		ret = yas537_get_calibration_data(yas5xx);
+		if (ret)
+			goto assert_reset;
+		dev_info(dev, "detected YAS537 MS-3T version %s",
+			 yas5xx->version ? "1" : "0");
+		strncpy(yas5xx->name, "yas537", sizeof(yas5xx->name));
+
+		yas537_dump_calibration(yas5xx);
+		ret = yas537_power_on(yas5xx);
 		if (ret)
 			goto assert_reset;
-		dev_info(dev, "detected YAS532/YAS533 MS-3R/F %s",
-			 yas5xx->version ? "AC" : "AB");
-		strncpy(yas5xx->name, "yas532", sizeof(yas5xx->name));
 		break;
+
 	default:
 		ret = -ENODEV;
 		dev_err(dev, "unhandled device ID %02x\n", yas5xx->devid);
 		goto assert_reset;
 	}
 
-	yas530_532_dump_calibration(yas5xx);
-	ret = yas530_532_power_on(yas5xx);
-	if (ret)
-		goto assert_reset;
-	ret = yas530_532_measure_offsets(yas5xx);
-	if (ret)
-		goto assert_reset;
-

drivers/iio/magnetometer/yamaha-yas530.c +0 -0

 	indio_dev->info = &yas5xx_info;
 	indio_dev->available_scan_masks = yas5xx_scan_masks;
 	indio_dev->modes = INDIO_DIRECT_MODE;

drivers/iio/magnetometer/yamaha-yas530.c +9 -0

+		break;
+	case YAS537_DEVICE_ID:
+		ret = yas537_power_on(yas5xx);
+		break;
+	default:
+		dev_err(yas5xx->dev, "unknown device type\n");
+		ret = -EINVAL;
+		break;
+	}
 	if (ret) {
 		dev_err(dev, "cannot power on\n");
 		goto out_reset;

On Sat, 18 Jun 2022 02:13:16 +0200
Jakob Hauser <[email protected]> wrote:

Quoted 1 line

+ for (i = 0; i < 17; i++) {

Reduce indent by doing this as multiple loops.
Though even better if you can use bulk writes.

                int j = 0;
                for (i = 0; i < 12; i++) {
                        ret = regmap_write(yas5xx->map, YAS537_MTC + i,
                                           data[j++])
                        if (ret)
                                return ret;
                }

                for (i = 0; i < 4; i++) {
                        ret = regmap_write(yas5xx->map, YAS573_OFFSET_X + i,
                                           data[j++]);
                        if (ret)
                                return ret;
                }

Quoted 21 lines

drivers/iio/magnetometer/yamaha-yas530.c +21 -0

+                     if (i < 12) {
+                             ret = regmap_write(yas5xx->map,
+                                                YAS537_MTC + i,
+                                                data[i]);
+                             if (ret)
+                                     return ret;
+                     } else if (i < 15) {
+                             ret = regmap_write(yas5xx->map,
+                                                YAS537_OFFSET_X + i - 12,
+                                                data[i]);
+                             if (ret)
+                                     return ret;
+                             yas5xx->hard_offsets[i - 12] = data[i];
+                     } else {
+                             ret = regmap_write(yas5xx->map,
+                                                YAS537_HCK + i - 15,
+                                                data[i]);
+                             if (ret)
+                                     return ret;
+                     }
+             }

Quoted 2 lines · Jonathan Cameron

On Sat, 18 Jun 2022 02:13:16 +0200
Jakob Hauser <[email protected]> wrote:

...

Quoted 13 lines

Quoted 1 line

+ for (i = 0; i < 17; i++) {

Reduce indent by doing this as multiple loops.
Though even better if you can use bulk writes.

                int j = 0;
                for (i = 0; i < 12; i++) {
                        ret = regmap_write(yas5xx->map, YAS537_MTC + i,
                                           data[j++])
                        if (ret)
                                return ret;
                }

Quoted 6 lines

                for (i = 0; i < 4; i++) {
                        ret = regmap_write(yas5xx->map, YAS573_OFFSET_X + i,
                                           data[j++]);
                        if (ret)
                                return ret;
                }  

I guess you are referring to _noinc variants of regmap bulk operations.

Quoted 22 lines

Quoted 22 lines

drivers/iio/magnetometer/yamaha-yas530.c +21 -0

+                     if (i < 12) {
+                             ret = regmap_write(yas5xx->map,
+                                                YAS537_MTC + i,
+                                                data[i]);
+                             if (ret)
+                                     return ret;
+                     } else if (i < 15) {
+                             ret = regmap_write(yas5xx->map,
+                                                YAS537_OFFSET_X + i - 12,
+                                                data[i]);
+                             if (ret)
+                                     return ret;
+                             yas5xx->hard_offsets[i - 12] = data[i];
+                     } else {
+                             ret = regmap_write(yas5xx->map,
+                                                YAS537_HCK + i - 15,
+                                                data[i]);
+                             if (ret)
+                                     return ret;
+                     }
+             }  

On Sat, 18 Jun 2022 02:13:16 +0200
Jakob Hauser <[email protected]> wrote:

drivers/iio/magnetometer/Kconfig config YAMAHA_YAS530 · line 220

Quoted 12 lines

drivers/iio/magnetometer/Kconfig +2 -2

index 07eb619bcfe8..868128cee835 100644
@@ -216,8 +216,8 @@ config YAMAHA_YAS530
 	select IIO_TRIGGERED_BUFFER
 	help
 	  Say Y here to add support for the Yamaha YAS530 series of
-	  3-Axis Magnetometers. Right now YAS530, YAS532 and YAS533 are
-	  fully supported.
+	  3-Axis Magnetometers. Right now YAS530, YAS532, YAS533 and
+	  YAS537 are fully supported.

Whilst here I'd reduce this to

	  3-Axis Magnetometers. YAS530, YAS532, YAS533 and YAS537
	  are supported.

"Right now" provides no information - we are hardly likely to be talking about code at some stage in the past or future.
"fully" isn't all that well defined and doesn't add anything over supported.

Quoted 7 lines

drivers/iio/magnetometer/Kconfig +0 -0

 static int yas5xx_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val, int *val2,

@@ -450,7 +602,18 @@ static int yas5xx_read_raw(struct iio_dev *indio_dev,
 	case IIO_CHAN_INFO_PROCESSED:
 	case IIO_CHAN_INFO_RAW:
 		pm_runtime_get_sync(yas5xx->dev);

drivers/iio/magnetometer/Kconfig static int yas5xx_read_raw(struct iio_dev *indio_dev, · line 608

Quoted 5 lines

drivers/iio/magnetometer/Kconfig +4 -1

-		ret = yas5xx_get_measure(yas5xx, &t, &x, &y, &z);
+		switch (yas5xx->devid) {
+		case YAS530_DEVICE_ID:
+		case YAS532_DEVICE_ID:
+			ret = yas530_532_get_measure(yas5xx, &t, &x, &y, &z);

As below, use function pointers in a chip_info struct to avoid switch statements like this and give shorter + more readable code.

Quoted 29 lines

drivers/iio/magnetometer/Kconfig +29 -0

+static int yas537_get_calibration_data(struct yas5xx *yas5xx)
+{
+	struct yas5xx_calibration *c = &yas5xx->calibration;
+	u8 data[17];
+	u32 val1, val2, val3, val4;
+	int i, ret;
+
+	/* Writing SRST register, the exact meaning is unknown */
+	ret = regmap_write(yas5xx->map, YAS537_SRST, BIT(1));
+	if (ret)
+		return ret;
+
+	/* Calibration readout, YAS537 needs one readout only */
+	ret = regmap_bulk_read(yas5xx->map, YAS537_CAL, data, sizeof(data));
+	if (ret)
+		return ret;
+	dev_dbg(yas5xx->dev, "calibration data: %17ph\n", data);
+
+	/* Sanity check, is this all zeroes? */
+	if (!memchr_inv(data, 0x00, 16)) {
+		if (FIELD_GET(GENMASK(5, 0), data[16]) == 0)
+			dev_warn(yas5xx->dev, "calibration is blank!\n");
+	}
+
+	/* Contribute calibration data to the input pool for kernel entropy */
+	add_device_randomness(data, sizeof(data));
+
+	/* Extract version information */
+	yas5xx->version = FIELD_GET(GENMASK(7, 6), data[16]);

drivers/iio/magnetometer/Kconfig

Quoted 5 lines

drivers/iio/magnetometer/Kconfig +5 -0

+
+	/* There are two versions of YAS537 behaving differently */
+	switch (yas5xx->version) {
+
+	case YAS537_VERSION_0:

Seems like we might need more chip_info variants, though perhaps in this case it is worth handling it as a switch statement as hopefully the number of way s this is done for a given part number won't grow any further.

Quoted 16 lines

drivers/iio/magnetometer/Kconfig +16 -0

+
+		/*
+		 * The first version simply writes data back into registers:
+		 *
+		 * data[0]  YAS537_MTC		0x93
+		 * data[1]			0x94
+		 * data[2]			0x95
+		 * data[3]			0x96
+		 * data[4]			0x97
+		 * data[5]			0x98
+		 * data[6]			0x99
+		 * data[7]			0x9a
+		 * data[8]			0x9b
+		 * data[9]			0x9c
+		 * data[10]			0x9d
+		 * data[11] YAS537_OC		0x9e

drivers/iio/magnetometer/Kconfig

Quoted 10 lines

drivers/iio/magnetometer/Kconfig +10 -0

+		 *
+		 * data[12] YAS537_OFFSET_X	0x84
+		 * data[13] YAS537_OFFSET_Y1	0x85
+		 * data[14] YAS537_OFFSET_Y2	0x86
+		 *
+		 * data[15] YAS537_HCK		0x88
+		 * data[16] YAS537_LCK		0x89
+		 */
+
+		for (i = 0; i < 17; i++) {

Reduce indent by doing this as multiple loops.
Though even better if you can use bulk writes.

		int j = 0;
		for (i = 0; i < 12; i++) {
			ret = regmap_write(yas5xx->map, YAS537_MTC + i,
					   data[j++])
			if (ret)
				return ret;
		}

		for (i = 0; i < 4; i++) {
			ret = regmap_write(yas5xx->map, YAS573_OFFSET_X + i,
					   data[j++]);
			if (ret)
				return ret;
		} 	

Quoted 73 lines

drivers/iio/magnetometer/Kconfig +73 -0

+			if (i < 12) {
+				ret = regmap_write(yas5xx->map,
+						   YAS537_MTC + i,
+						   data[i]);
+				if (ret)
+					return ret;
+			} else if (i < 15) {
+				ret = regmap_write(yas5xx->map,
+						   YAS537_OFFSET_X + i - 12,
+						   data[i]);
+				if (ret)
+					return ret;
+				yas5xx->hard_offsets[i - 12] = data[i];
+			} else {
+				ret = regmap_write(yas5xx->map,
+						   YAS537_HCK + i - 15,
+						   data[i]);
+				if (ret)
+					return ret;
+			}
+		}
+
+		break;
+
+	case YAS537_VERSION_1:
+
+		/*
+		 * The second version writes some data into registers but also
+		 * extracts calibration coefficients.
+		 *
+		 * Registers being written:
+		 *
+		 * data[0]  YAS537_MTC			0x93
+		 * data[1]  YAS537_MTC+1		0x94
+		 * data[2]  YAS537_MTC+2		0x95
+		 * data[3]  YAS537_MTC+3 (partially)	0x96
+		 *
+		 * data[12] YAS537_OFFSET_X		0x84
+		 * data[13] YAS537_OFFSET_Y1		0x85
+		 * data[14] YAS537_OFFSET_Y2		0x86
+		 *
+		 * data[15] YAS537_HCK (partially)	0x88
+		 *          YAS537_LCK (partially)	0x89
+		 * data[16] YAS537_OC  (partially)	0x9e
+		 */
+
+		for (i = 0; i < 3; i++) {
+			ret = regmap_write(yas5xx->map, YAS537_MTC + i,
+					   data[i]);
+			if (ret)
+				return ret;
+			ret = regmap_write(yas5xx->map, YAS537_OFFSET_X + i,
+					   data[i + 12]);
+			if (ret)
+				return ret;
+			yas5xx->hard_offsets[i] = data[i + 12];
+		}
+
+		/*
+		 * Visualization of partially taken data:
+		 *
+		 * data[3]       n 7 6 5 4 3 2 1 0
+		 * YAS537_MTC+3    x x x 1 0 0 0 0
+		 *
+		 * data[15]      n 7 6 5 4 3 2 1 0
+		 * YAS537_HCK      x x x x 0
+		 *
+		 * data[15]      n 7 6 5 4 3 2 1 0
+		 * YAS537_LCK              x x x x 0
+		 *
+		 * data[16]      n 7 6 5 4 3 2 1 0
+		 * YAS537_OC           x x x x x x
+		 */