iio: accel: Add support for Kionix/ROHM KX132-1211 accelerometer

Hello everyone,

Version 7 for adding support for the kx132-1211 accelerometer

KX132-1211 accelerometer is a sensor which:
- supports G-ranges of (+/-) 2, 4, 8, and 16G
- can be connected to I2C or SPI
- has internal HW FIFO buffer
- supports various ODRs (output data rates)

The KX132-1211 accelerometer is very similar to the KX022A.
One key difference is number of bits to report the number of data bytes that have been stored in the buffer: 8 bits for KX022A vs 10 bits for KX132-1211.

Changes in v7:
- added a min_t in kx132_get_fifo_bytes to ensure that we don't that the fifo_bytes is never bigger than the
fifo_length * KX022A_FIFO_SAMPLES_SIZE_BYTES - no matter what we read from I2C as suggested by Matti

Changes in v6:
- check for availability of chip_info for the SPI case
- changed the order of elements in the kx022a_data struct to save memory

Changes in v5:
- moved the "kfree" call to match the reverse of what happens in kx022a_fifo_enable() as suggested by Matti and Jonathan
- used min_t, checked for availability of chip_info and moved the position of u16 buf_smp_lvl_mask as suggested by Andy
- introduced buf_smp_lvl_mask in Patch 7 as suggested by Jonathan

Changes in v4:
- moved the allocation of the fifo_buffer to kx022a_fifo_enable and kx022a_fifo_disable
- some fixes to the regmap ranges of kx132-1211

Changes in v3:
- added two new patches by separating the addition of the i2c_device_id table and the removal of blank lines from other unrelated changes
- fixes a warning detected by the kernel test robot
- made all the changes related the chip_info in one patch

Changes in v2:
- added a new patch for warning when the device_id match fails in the probe function
- added a new patch for the function that retrieves the number of bytes in the buffer
- added a change to the Kconfig file in the patch adding the support for the kx132-1211
- various fixes and modifications listed under each patch

Mehdi Djait (7):
dt-bindings: iio: Add KX132-1211 accelerometer
iio: accel: kionix-kx022a: Remove blank lines
iio: accel: kionix-kx022a: Warn on failed matches and assume
compatibility
iio: accel: kionix-kx022a: Add an i2c_device_id table
iio: accel: kionix-kx022a: Refactor driver and add chip_info structure
iio: accel: kionix-kx022a: Add a function to retrieve number of bytes
in buffer
iio: accel: Add support for Kionix/ROHM KX132-1211 accelerometer

 .../bindings/iio/accel/kionix,kx022a.yaml     |  12 +-
 drivers/iio/accel/Kconfig                     |   8 +-
 drivers/iio/accel/kionix-kx022a-i2c.c         |  24 +-
 drivers/iio/accel/kionix-kx022a-spi.c         |  15 +-
 drivers/iio/accel/kionix-kx022a.c             | 314 ++++++++++++++----
 drivers/iio/accel/kionix-kx022a.h             | 110 +++++-
 6 files changed, 408 insertions(+), 75 deletions(-)

2.30.2

Extend the kionix,kx022a.yaml file to support the kx132-1211 device

---
v7:
v6:
v5:
v4:
v3:
- no changes

v2:
- made the device name more specific from "kx132" to "kx132-1211"
- removed the output data-rates mentioned and replaced them with "variable output data-rates"

 .../devicetree/bindings/iio/accel/kionix,kx022a.yaml | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

index 986df1a6ff0a..034b69614416 100644
@@ -4,19 +4,21 @@
 $id: http://devicetree.org/schemas/iio/accel/kionix,kx022a.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: ROHM/Kionix KX022A Accelerometer
+title: ROHM/Kionix KX022A and KX132-1211 Accelerometers
 
 maintainers:
   - Matti Vaittinen <[email protected]>
 
 description: |
-  KX022A is a 3-axis accelerometer supporting +/- 2G, 4G, 8G and 16G ranges,
-  output data-rates from 0.78Hz to 1600Hz and a hardware-fifo buffering.
-  KX022A can be accessed either via I2C or SPI.
+  KX022A and KX132-1211 are 3-axis accelerometers supporting +/- 2G, 4G, 8G and
+  16G ranges, variable output data-rates and a hardware-fifo buffering.
+  KX022A and KX132-1211 can be accessed either via I2C or SPI.
 
 properties:
   compatible:
-    const: kionix,kx022a
+    enum:
+      - kionix,kx022a
+      - kionix,kx132-1211
 
   reg:
     maxItems: 1

2.30.2

Remove blank lines pointed out by the checkpatch script

---
v7:
v6:
v5:
v4:
- no changes

v3:
- no changes, this patch is introduced in the v2

 drivers/iio/accel/kionix-kx022a.c | 2 --
 1 file changed, 2 deletions(-)

index f98393d74666..ff8aa7b9568e 100644
@@ -341,7 +341,6 @@ static int kx022a_turn_on_off_unlocked(struct kx022a_data *data, bool on)
 		dev_err(data->dev, "Turn %s fail %d\n", str_on_off(on), ret);
 
 	return ret;
-
 }
 
 static int kx022a_turn_off_lock(struct kx022a_data *data)

@@ -1121,7 +1120,6 @@ int kx022a_probe_internal(struct device *dev)
 	if (ret)
 		return dev_err_probe(data->dev, ret, "Could not request IRQ\n");
 
-
 	ret = devm_iio_trigger_register(dev, indio_trig);
 	if (ret)
 		return dev_err_probe(data->dev, ret,

2.30.2

Avoid error returns on a failure to match and instead just warn with assumption that we have a correct dt-binding telling us that some new device with a different ID is backwards compatible.

---
v7:
v6:
v5:
v4:
- no changes

v3:
- changed from 'unsupported' to 'unknown'
- removed the opening bracket

v2:
- no changes, this patch is introduced in the v2

 drivers/iio/accel/kionix-kx022a.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

index ff8aa7b9568e..494e81ba1da9 100644
@@ -1036,10 +1036,8 @@ int kx022a_probe_internal(struct device *dev)
 	if (ret)
 		return dev_err_probe(dev, ret, "Failed to access sensor\n");
 
-	if (chip_id != KX022A_ID) {
-		dev_err(dev, "unsupported device 0x%x\n", chip_id);
-		return -EINVAL;
-	}
+	if (chip_id != KX022A_ID)
+		dev_warn(dev, "unknown device 0x%x\n", chip_id);
 
 	irq = fwnode_irq_get_byname(fwnode, "INT1");
 	if (irq > 0) {

2.30.2

Add the missing i2c device id.

---
v7:
v6:
v5:
v4:
- no changes

v3:
- no changes, this patch is introduced in the v2

 drivers/iio/accel/kionix-kx022a-i2c.c | 7 +++++++
 1 file changed, 7 insertions(+)

index e6fd02d931b6..b5a85ce3a891 100644
@@ -30,6 +30,12 @@ static int kx022a_i2c_probe(struct i2c_client *i2c)
 	return kx022a_probe_internal(dev);
 }
 
+static const struct i2c_device_id kx022a_i2c_id[] = {
+	{ .name = "kx022a" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, kx022a_i2c_id);
+
 static const struct of_device_id kx022a_of_match[] = {
 	{ .compatible = "kionix,kx022a", },
 	{ }

@@ -42,6 +48,7 @@ static struct i2c_driver kx022a_i2c_driver = {
 		.of_match_table = kx022a_of_match,
 	  },
 	.probe_new    = kx022a_i2c_probe,
+	.id_table     = kx022a_i2c_id,
 };
 module_i2c_driver(kx022a_i2c_driver);
 

2.30.2

Add the chip_info structure to the driver's private data to hold all the device specific infos.
Refactor the kx022a driver implementation to make it more generic and extensible.

---
v7:
- no changes

v6:
- placed chip_info after the regmap elemnt in kx022a_data struct to save memory as suggested by Andy
- added a check for the availability of chip_info for the SPI case as suggested by Andy

v5:
- moved the "kfree" call to match the reverse of what happens in kx022a_fifo_enable() as suggested by Matti and Jonathan
- used min_t, checked for availability of chip_info as suggested by Andy

v4:
- allocating and freeing the buffer moved to the kx022a_fifo{enable, disable} functions
- used the spi_get_device_match_data helper function

v3:
- added the change of the buffer's allocation in the __kx022a_fifo_flush to this patch
- added the chip_info to the struct kx022a_data

 drivers/iio/accel/kionix-kx022a-i2c.c |  17 +++-
 drivers/iio/accel/kionix-kx022a-spi.c |  13 ++-
 drivers/iio/accel/kionix-kx022a.c     | 116 ++++++++++++++++----------
 drivers/iio/accel/kionix-kx022a.h     |  52 +++++++++++-
 4 files changed, 146 insertions(+), 52 deletions(-)

index b5a85ce3a891..c59558fc6493 100644
@@ -15,6 +15,7 @@
 static int kx022a_i2c_probe(struct i2c_client *i2c)
 {
 	struct device *dev = &i2c->dev;
+	const struct kx022a_chip_info *chip_info;
 	struct regmap *regmap;
 
 	if (!i2c->irq) {

@@ -22,22 +23,30 @@ static int kx022a_i2c_probe(struct i2c_client *i2c)
 		return -EINVAL;
 	}
 
-	regmap = devm_regmap_init_i2c(i2c, &kx022a_regmap);
+	chip_info = device_get_match_data(&i2c->dev);
+	if (!chip_info) {
+		const struct i2c_device_id *id = i2c_client_get_device_id(i2c);
+		chip_info = (const struct kx022a_chip_info *)id->driver_data;
+		if (!chip_info)
+			return -EINVAL;
+	}
+
+	regmap = devm_regmap_init_i2c(i2c, chip_info->regmap_config);
 	if (IS_ERR(regmap))
 		return dev_err_probe(dev, PTR_ERR(regmap),
 				     "Failed to initialize Regmap\n");
 
-	return kx022a_probe_internal(dev);
+	return kx022a_probe_internal(dev, chip_info);
 }
 
 static const struct i2c_device_id kx022a_i2c_id[] = {
-	{ .name = "kx022a" },
+	{ .name = "kx022a", .driver_data = (kernel_ulong_t)&kx022a_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, kx022a_i2c_id);
 
 static const struct of_device_id kx022a_of_match[] = {
-	{ .compatible = "kionix,kx022a", },
+	{ .compatible = "kionix,kx022a", .data = &kx022a_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, kx022a_of_match);

index 9cd047f7b346..896b57866fc9 100644
@@ -15,6 +15,7 @@
 static int kx022a_spi_probe(struct spi_device *spi)
 {
 	struct device *dev = &spi->dev;
+	const struct kx022a_chip_info *chip_info;
 	struct regmap *regmap;
 
 	if (!spi->irq) {

@@ -22,22 +23,26 @@ static int kx022a_spi_probe(struct spi_device *spi)
 		return -EINVAL;
 	}
 
-	regmap = devm_regmap_init_spi(spi, &kx022a_regmap);
+	chip_info = spi_get_device_match_data(spi);
+	if (!chip_info)
+		return -EINVAL;
+
+	regmap = devm_regmap_init_spi(spi, chip_info->regmap_config);
 	if (IS_ERR(regmap))
 		return dev_err_probe(dev, PTR_ERR(regmap),
 				     "Failed to initialize Regmap\n");
 
-	return kx022a_probe_internal(dev);
+	return kx022a_probe_internal(dev, chip_info);
 }
 
 static const struct spi_device_id kx022a_id[] = {
-	{ "kx022a" },
+	{ .name = "kx022a", .driver_data = (kernel_ulong_t)&kx022a_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, kx022a_id);
 
 static const struct of_device_id kx022a_of_match[] = {
-	{ .compatible = "kionix,kx022a", },
+	{ .compatible = "kionix,kx022a", .data = &kx022a_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, kx022a_of_match);

2.30.2

...

...

With Best Regards,
Andy Shevchenko

Hello Andy,

Thank you for the review.

No actual reason, you suggested min_t or min for a previous version

Should I send another version for this ?
The usage of kmalloc is quite straightforward and easy to understand here.

--
Kind Regard
Mehdi Djait

...

After the minmax series (see discussion in LKML) I am pretty sure min_t() shouldn't be used at all or with very minimum cases where people know what they are doing.

...

Sure.

Yes, and prone to errors. Multiplication theoretically may overflow and your code doesn't aware of that, kmalloc_array() does it.

With Best Regards,
Andy Shevchenko

Since Kionix accelerometers use various numbers of bits to report data, a device-specific function is required.
Implement the function as a callback in the device-specific chip_info structure

---
v7:
- no changes

v6:
- directly return KX022A_FIFO_MAX_BYTES as suggested by Andy

v5:
- no changes

v4:
- removed the comment about "bogus value from i2c"
- removed regmap_get_device(data->regmap); dev is present in the driver's private data

v3:
- no changes

v2:
- separated this change from the chip_info introduction and made it a patch in v2
- changed the function from generic implementation for to device-specific one
- removed blank lines pointed out by checkpatch
- changed the allocation of the "buffer" array in __kx022a_fifo_flush

 drivers/iio/accel/kionix-kx022a.c | 28 ++++++++++++++++++----------
 drivers/iio/accel/kionix-kx022a.h |  4 ++++
 2 files changed, 22 insertions(+), 10 deletions(-)

index 0bab3f109e4e..0b0f14dca17f 100644
@@ -596,26 +596,33 @@ static int kx022a_drop_fifo_contents(struct kx022a_data *data)
 	return regmap_write(data->regmap, data->chip_info->buf_clear, 0x0);
 }
 
+static int kx022a_get_fifo_bytes(struct kx022a_data *data)
+{
+	int ret, fifo_bytes;
+
+	ret = regmap_read(data->regmap, KX022A_REG_BUF_STATUS_1, &fifo_bytes);
+	if (ret) {
+		dev_err(data->dev, "Error reading buffer status\n");
+		return ret;
+	}
+
+	if (fifo_bytes == KX022A_FIFO_FULL_VALUE)
+		return KX022A_FIFO_MAX_BYTES;
+
+	return fifo_bytes;
+}
+
 static int __kx022a_fifo_flush(struct iio_dev *idev, unsigned int samples,
 			       bool irq)
 {
 	struct kx022a_data *data = iio_priv(idev);
-	struct device *dev = regmap_get_device(data->regmap);
 	uint64_t sample_period;
 	int count, fifo_bytes;
 	bool renable = false;
 	int64_t tstamp;
 	int ret, i;
 
-	ret = regmap_read(data->regmap, KX022A_REG_BUF_STATUS_1, &fifo_bytes);
-	if (ret) {
-		dev_err(dev, "Error reading buffer status\n");
-		return ret;
-	}
-
-	/* Let's not overflow if we for some reason get bogus value from i2c */
-	if (fifo_bytes == KX022A_FIFO_FULL_VALUE)
-		fifo_bytes = KX022A_FIFO_MAX_BYTES;
+	fifo_bytes = data->chip_info->get_fifo_bytes(data);
 
 	if (fifo_bytes % KX022A_FIFO_SAMPLES_SIZE_BYTES)
 		dev_warn(data->dev, "Bad FIFO alignment. Data may be corrupt\n");

@@ -1023,6 +1030,7 @@ const struct kx022a_chip_info kx022a_chip_info = {
 	.inc5		  = KX022A_REG_INC5,
 	.inc6		  = KX022A_REG_INC6,
 	.xout_l		  = KX022A_REG_XOUT_L,
+	.get_fifo_bytes	  = kx022a_get_fifo_bytes,
 };
 EXPORT_SYMBOL_NS_GPL(kx022a_chip_info, IIO_KX022A);
 

index 0e5026019213..c9f9aee7e597 100644
@@ -76,6 +76,8 @@
 
 struct device;
 
+struct kx022a_data;
+
 /**
  * struct kx022a_chip_info - Kionix accelerometer chip specific information
  *

@@ -99,6 +101,7 @@ struct device;
  * @inc5:		interrupt control register 5
  * @inc6:		interrupt control register 6
  * @xout_l:		x-axis output least significant byte
+ * @get_fifo_bytes:	function pointer to get number of bytes in the FIFO buffer
  */
 struct kx022a_chip_info {
 	const char *name;

@@ -121,6 +124,7 @@ struct kx022a_chip_info {
 	u8 inc5;
 	u8 inc6;
 	u8 xout_l;
+	int (*get_fifo_bytes)(struct kx022a_data *);
 };
 
 int kx022a_probe_internal(struct device *dev, const struct kx022a_chip_info *chip_info);

2.30.2

Kionix KX132-1211 is a tri-axis 16-bit accelerometer that can support ranges from ±2G to ±16G, digital output through I²C/SPI.
Add support for basic accelerometer features such as reading acceleration via IIO using raw reads, triggered buffer (data-ready), or the WMI IRQ.

Datasheet: https://kionixfs.azureedge.net/en/document/KX132-1211-Technical-Reference-Manual-Rev-5.0.pdf

---
v7:
- added a min_t in kx132_get_fifo_bytes to ensure that we don't that the fifo_bytes is never bigger than the
fifo_length * KX022A_FIFO_SAMPLES_SIZE_BYTES - no matter what we read from I2C as suggested by Matti

v6:
- no changes

v5:
- moved the position of u16 buf_smp_lvl_mask as suggested by Andy
- introduced buf_smp_lvl_mask in Patch 7 as suggested by Jonathan

v4:
- added KX132_REG_CNTL5 to the volatile ranges
- added the kionix reserved regs to the read_only ranges
- removed KX132_REG_MAN_WAKEUP from the write_only ranges

v3:
- fixed the warning of the kernel test robot in kx132_get_fifo_bytes (invalid assignment: &=, left side has type restricted __le16 right side has type unsigned short)

v2:
- mentioned the kx132-1211 in the Kconfig
- added a kx132-specific get_fifo_bytes function
- changed the device name from "kx132" to "kx132-1211

 drivers/iio/accel/Kconfig             |   8 +-
 drivers/iio/accel/kionix-kx022a-i2c.c |   2 +
 drivers/iio/accel/kionix-kx022a-spi.c |   2 +
 drivers/iio/accel/kionix-kx022a.c     | 164 ++++++++++++++++++++++++++
 drivers/iio/accel/kionix-kx022a.h     |  54 +++++++++
 5 files changed, 226 insertions(+), 4 deletions(-)

index b6b45d359f28..d8cc6e6f2bb9 100644
@@ -418,8 +418,8 @@ config IIO_KX022A_SPI
 	select IIO_KX022A
 	select REGMAP_SPI
 	help
-	  Enable support for the Kionix KX022A digital tri-axis
-	  accelerometer connected to I2C interface.
+	  Enable support for the Kionix KX022A, KX132-1211 digital tri-axis
+	  accelerometers connected to SPI interface.
 
 config IIO_KX022A_I2C
 	tristate "Kionix KX022A tri-axis digital accelerometer I2C interface"

@@ -427,8 +427,8 @@ config IIO_KX022A_I2C
 	select IIO_KX022A
 	select REGMAP_I2C
 	help
-	  Enable support for the Kionix KX022A digital tri-axis
-	  accelerometer connected to I2C interface.
+	  Enable support for the Kionix KX022A, KX132-1211 digital tri-axis
+	  accelerometers connected to I2C interface.
 
 config KXSD9
 	tristate "Kionix KXSD9 Accelerometer Driver"

index c59558fc6493..0f4729c55d29 100644
@@ -41,12 +41,14 @@ static int kx022a_i2c_probe(struct i2c_client *i2c)
 
 static const struct i2c_device_id kx022a_i2c_id[] = {
 	{ .name = "kx022a", .driver_data = (kernel_ulong_t)&kx022a_chip_info },
+	{ .name = "kx132-1211", .driver_data = (kernel_ulong_t)&kx132_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, kx022a_i2c_id);
 
 static const struct of_device_id kx022a_of_match[] = {
 	{ .compatible = "kionix,kx022a", .data = &kx022a_chip_info },
+	{ .compatible = "kionix,kx132-1211", .data = &kx132_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, kx022a_of_match);

index 896b57866fc9..c7766492bcd9 100644
@@ -37,12 +37,14 @@ static int kx022a_spi_probe(struct spi_device *spi)
 
 static const struct spi_device_id kx022a_id[] = {
 	{ .name = "kx022a", .driver_data = (kernel_ulong_t)&kx022a_chip_info },
+	{ .name = "kx132-1211", .driver_data = (kernel_ulong_t)&kx132_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, kx022a_id);
 
 static const struct of_device_id kx022a_of_match[] = {
 	{ .compatible = "kionix,kx022a", .data = &kx022a_chip_info },
+	{ .compatible = "kionix,kx132-1211", .data = &kx132_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, kx022a_of_match);

2.30.2

Thanks a lot Mehdi! Looks good to me :)

Yours,
-- Matti

Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~