Few non-critical cpcap ADC fixes

Looking at the register dumps from Android kernel on droid 4, I noticed the values with the mainline kernel don't match. Let's fix this by initializing the ADC registers to what Android does.

For getting correct values from the battery thermistor, we need to toggle the CPCAP_BIT_THERMBIAS_EN when measuring battery temperature to get correct battery temperatures. And looks like we also need to wait a little bit before reading the battery temperature as otherwise the results are inaccurate.

Cc Marcel Partap <[email protected]>

Cc Michael Scott <[email protected]>

Cc Sebastian Reichel <[email protected]>

Signed-off-by Tony Lindgren <[email protected]>

---
 drivers/iio/adc/cpcap-adc.c | 58 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 50 insertions(+), 8 deletions(-)

drivers/iio/adc/cpcap-adc.c +50 -8

@@ -52,6 +52,10 @@
 #define CPCAP_BIT_RAND0			BIT(1)	/* Set with CAL_MODE */
 #define CPCAP_BIT_ADEN			BIT(0)	/* Currently unused */
 
+#define CPCAP_REG_ADCC1_DEFAULTS	(CPCAP_BIT_ADEN_AUTO_CLR | \
+					 CPCAP_BIT_ADC_CLK_SEL0 |  \
+					 CPCAP_BIT_RAND1)
+
 /* Register CPCAP_REG_ADCC2 bits */
 #define CPCAP_BIT_CAL_FACTOR_ENABLE	BIT(15)	/* Currently unused */
 #define CPCAP_BIT_BATDETB_EN		BIT(14)	/* Currently unused */

@@ -62,7 +66,7 @@
 #define CPCAP_BIT_ADC_PS_FACTOR0	BIT(9)
 #define CPCAP_BIT_AD4_SELECT		BIT(8)	/* Currently unused */
 #define CPCAP_BIT_ADC_BUSY		BIT(7)	/* Currently unused */
-#define CPCAP_BIT_THERMBIAS_EN		BIT(6)	/* Currently unused */
+#define CPCAP_BIT_THERMBIAS_EN		BIT(6)	/* Bias for AD0_BATTDETB */
 #define CPCAP_BIT_ADTRIG_DIS		BIT(5)	/* Disable interrupt */
 #define CPCAP_BIT_LIADC			BIT(4)	/* Currently unused */
 #define CPCAP_BIT_TS_REFEN		BIT(3)	/* Currently unused */

@@ -70,6 +74,13 @@
 #define CPCAP_BIT_TS_M1			BIT(1)	/* Currently unused */
 #define CPCAP_BIT_TS_M0			BIT(0)	/* Currently unused */
 
+#define CPCAP_REG_ADCC2_DEFAULTS	(CPCAP_BIT_AD4_SELECT | \
+					 CPCAP_BIT_ADTRIG_DIS | \
+					 CPCAP_BIT_ADTRIG_DIS | \
+					 CPCAP_BIT_LIADC | \
+					 CPCAP_BIT_TS_M2 | \
+					 CPCAP_BIT_TS_M1)
+
 #define CPCAP_MAX_TEMP_LVL		27
 #define CPCAP_FOUR_POINT_TWO_ADC	801
 #define ST_ADC_CAL_CHRGI_HIGH_THRESHOLD	530

@@ -124,10 +135,10 @@ struct cpcap_adc {
  */
 enum cpcap_adc_channel {
 	/* Bank0 channels */
-	CPCAP_ADC_AD0_BATTDETB,	/* Battery detection */
+	CPCAP_ADC_AD0,		/* Battery temperature */
 	CPCAP_ADC_BATTP,	/* Battery voltage */
 	CPCAP_ADC_VBUS,		/* USB VBUS voltage */
-	CPCAP_ADC_AD3,		/* Battery temperature when charging */
+	CPCAP_ADC_AD3,		/* Die temperature when charging */
 	CPCAP_ADC_BPLUS_AD4,	/* Another battery or system voltage */
 	CPCAP_ADC_CHG_ISENSE,	/* Calibrated charge current */
 	CPCAP_ADC_BATTI,	/* Calibrated system current */

@@ -217,7 +228,7 @@ struct cpcap_adc_request {
 /* Phasing table for channels. Note that channels 16 & 17 use BATTP and BATTI */
 static const struct cpcap_adc_phasing_tbl bank_phasing[] = {
 	/* Bank0 */
-	[CPCAP_ADC_AD0_BATTDETB] = {0, 0x80, 0x80,    0, 1023},
+	[CPCAP_ADC_AD0] =          {0, 0x80, 0x80,    0, 1023},
 	[CPCAP_ADC_BATTP] =        {0, 0x80, 0x80,    0, 1023},
 	[CPCAP_ADC_VBUS] =         {0, 0x80, 0x80,    0, 1023},
 	[CPCAP_ADC_AD3] =          {0, 0x80, 0x80,    0, 1023},

@@ -243,7 +254,7 @@ static const struct cpcap_adc_phasing_tbl bank_phasing[] = {
  */
 static struct cpcap_adc_conversion_tbl bank_conversion[] = {
 	/* Bank0 */
-	[CPCAP_ADC_AD0_BATTDETB] = {
+	[CPCAP_ADC_AD0] = {
 		IIO_CHAN_INFO_PROCESSED,    0,    0, 0,     1,    1,
 	},
 	[CPCAP_ADC_BATTP] = {

@@ -541,6 +552,15 @@ static void cpcap_adc_setup_bank(struct cpcap_adc *ddata,
 		return;
 
 	switch (req->channel) {
+	case CPCAP_ADC_AD0:
+		value2 |= CPCAP_BIT_THERMBIAS_EN;
+		error = regmap_update_bits(ddata->reg, CPCAP_REG_ADCC2,
+					   CPCAP_BIT_THERMBIAS_EN,
+					   value2);
+		if (error)
+			return;
+		usleep_range(800, 1000);
+		break;
 	case CPCAP_ADC_AD8 ... CPCAP_ADC_TSY2_AD15:
 		value1 |= CPCAP_BIT_AD_SEL1;
 		break;

@@ -583,7 +603,8 @@ static void cpcap_adc_setup_bank(struct cpcap_adc *ddata,
 	error = regmap_update_bits(ddata->reg, CPCAP_REG_ADCC2,
 				   CPCAP_BIT_ATOX_PS_FACTOR |
 				   CPCAP_BIT_ADC_PS_FACTOR1 |
-				   CPCAP_BIT_ADC_PS_FACTOR0,
+				   CPCAP_BIT_ADC_PS_FACTOR0 |
+				   CPCAP_BIT_THERMBIAS_EN,
 				   value2);
 	if (error)
 		return;

@@ -664,6 +685,21 @@ static int cpcap_adc_start_bank(struct cpcap_adc *ddata,
 	return error;
 }
 
+static int cpcap_adc_stop_bank(struct cpcap_adc *ddata)
+{
+	int error;
+
+	error = regmap_update_bits(ddata->reg, CPCAP_REG_ADCC1,
+				   0xffff,
+				   CPCAP_REG_ADCC1_DEFAULTS);
+	if (error)
+		return error;
+
+	return regmap_update_bits(ddata->reg, CPCAP_REG_ADCC2,
+				  0xffff,
+				  CPCAP_REG_ADCC2_DEFAULTS);
+}
+
 static void cpcap_adc_phase(struct cpcap_adc_request *req)
 {
 	const struct cpcap_adc_conversion_tbl *conv_tbl = req->conv_tbl;

@@ -758,7 +794,7 @@ static void cpcap_adc_convert(struct cpcap_adc_request *req)
 		return;
 
 	/* Temperatures use a lookup table instead of conversion table */
-	if ((req->channel == CPCAP_ADC_AD0_BATTDETB) ||
+	if ((req->channel == CPCAP_ADC_AD0) ||
 	    (req->channel == CPCAP_ADC_AD3)) {
 		req->result =
 			cpcap_adc_table_to_millicelcius(req->result);

@@ -820,7 +856,7 @@ static int cpcap_adc_init_request(struct cpcap_adc_request *req,
 	req->conv_tbl = bank_conversion;
 
 	switch (channel) {
-	case CPCAP_ADC_AD0_BATTDETB ... CPCAP_ADC_USB_ID:
+	case CPCAP_ADC_AD0 ... CPCAP_ADC_USB_ID:
 		req->bank_index = channel;
 		break;
 	case CPCAP_ADC_AD8 ... CPCAP_ADC_TSY2_AD15:

@@ -860,6 +896,9 @@ static int cpcap_adc_read(struct iio_dev *indio_dev,
 		error = regmap_read(ddata->reg, chan->address, val);
 		if (error)
 			goto err_unlock;
+		error = cpcap_adc_stop_bank(ddata);
+		if (error)
+			goto err_unlock;
 		mutex_unlock(&ddata->lock);
 		break;
 	case IIO_CHAN_INFO_PROCESSED:

@@ -870,6 +909,9 @@ static int cpcap_adc_read(struct iio_dev *indio_dev,
 		error = cpcap_adc_read_bank_scaled(ddata, &req);
 		if (error)
 			goto err_unlock;
+		error = cpcap_adc_stop_bank(ddata);
+		if (error)
+			goto err_unlock;
 		mutex_unlock(&ddata->lock);
 		*val = req.result;
 		break;

Quoted 10 lines · On Mon, 22 May 2017 17:51:44 -0700 Tony Lindgren <[email protected]> wrote:

Looking at the register dumps from Android kernel on droid 4, I noticed the values with the mainline kernel don't match. Let's fix this by initializing the ADC registers to what Android does.

For getting correct values from the battery thermistor, we need to toggle the CPCAP_BIT_THERMBIAS_EN when measuring battery temperature to get correct battery temperatures. And looks like we also need to wait a little bit before reading the battery temperature as otherwise the results are inaccurate.

Quoted 4 lines

Cc Marcel Partap <[email protected]>

Cc Michael Scott <[email protected]>

Cc Sebastian Reichel <[email protected]>

Signed-off-by Tony Lindgren <[email protected]>

Applied to the togreg branch of iio.git and will be shortly pushed out as testing for the autobuilders to play with it.

Quoted 17 lines · Jonathan Cameron

Quoted 14 lines · On Mon, 22 May 2017 17:51:44 -0700 Tony Lindgren…

Looking at the register dumps from Android kernel on droid 4, I noticed the values with the mainline kernel don't match. Let's fix this by initializing the ADC registers to what Android does.

For getting correct values from the battery thermistor, we need to toggle the CPCAP_BIT_THERMBIAS_EN when measuring battery temperature to get correct battery temperatures. And looks like we also need to wait a little bit before reading the battery temperature as otherwise the results are inaccurate.

Cc Marcel Partap <[email protected]>

Cc Michael Scott <[email protected]>

Cc Sebastian Reichel <[email protected]>

Signed-off-by Tony Lindgren <[email protected]>

Quoted 2 lines

Applied to the togreg branch of iio.git and will be shortly pushed out as testing for the autobuilders to play with it.

Not seeing these in your togreg brach or in next? The branch I just checked is the one below, maybe I'm looking at a wrong branch or something.

Regards,

Tony

https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/log/?h=togreg

It seems that "MC13783 Power Management and Audio Ciruit User's Guide" MC1378UG.pdf documents several similar components as in the CPCAP PMIC.

Chapter "9.5.5 Die Temperature and UID" says that the die temperature value is 282 at 25C with LSB of -1.14C. Converting CPCAP PMIC channel3 values with following seems to produce values that make sense for a PMIC die:

temperature = 25000 + ((regval - 282) * 114)

As we don't have any other documentation, let's assume the die temperature is unconfigured in the Motorola mapphone Linux kernel and the current temperature conversion table should be only used for the battery thermistor and not for the die temperature.

Cc Marcel Partap <[email protected]>

Cc Michael Scott <[email protected]>

Cc Sebastian Reichel <[email protected]>

Signed-off-by Tony Lindgren <[email protected]>

---
 drivers/iio/adc/cpcap-adc.c | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

drivers/iio/adc/cpcap-adc.c +28 -3

@@ -875,6 +875,22 @@ static int cpcap_adc_init_request(struct cpcap_adc_request *req,
 	return 0;
 }
 
+static int cpcap_adc_read_st_die_temp(struct cpcap_adc *ddata,
+				      int addr, int *val)
+{
+	int error;
+
+	error = regmap_read(ddata->reg, addr, val);
+	if (error)
+		return error;
+
+	*val -= 282;
+	*val *= 114;
+	*val += 25000;
+
+	return 0;
+}
+
 static int cpcap_adc_read(struct iio_dev *indio_dev,
 			  struct iio_chan_spec const *chan,
 			  int *val, int *val2, long mask)

@@ -906,9 +922,18 @@ static int cpcap_adc_read(struct iio_dev *indio_dev,
 		error = cpcap_adc_start_bank(ddata, &req);
 		if (error)
 			goto err_unlock;
-		error = cpcap_adc_read_bank_scaled(ddata, &req);
-		if (error)
-			goto err_unlock;
+		if ((ddata->vendor == CPCAP_VENDOR_ST) &&
+		    (chan->channel == CPCAP_ADC_AD3)) {
+			error = cpcap_adc_read_st_die_temp(ddata,
+							   chan->address,
+							   &req.result);
+			if (error)
+				goto err_unlock;
+		} else {
+			error = cpcap_adc_read_bank_scaled(ddata, &req);
+			if (error)
+				goto err_unlock;
+		}
 		error = cpcap_adc_stop_bank(ddata);
 		if (error)
 			goto err_unlock;

This is no longer needed as the real problem was interrupt flags not getting passed properly from device tree to the cpcap-core.c mfd driver. This got fixed with commit ac89473213c6 ("mfd: cpcap:
Fix interrupt to use level interrupt") So let's remove ADC interrupt specific the quirk.

Cc Marcel Partap <[email protected]>

Cc Michael Scott <[email protected]>

Reviewed-by Sebastian Reichel <[email protected]>

Signed-off-by Tony Lindgren <[email protected]>

---
 drivers/iio/adc/cpcap-adc.c | 24 +-----------------------
 1 file changed, 1 insertion(+), 23 deletions(-)

drivers/iio/adc/cpcap-adc.c +1 -23

@@ -89,7 +89,7 @@
 #define ST_ADC_CAL_BATTI_LOW_THRESHOLD	494
 #define ST_ADC_CALIBRATE_DIFF_THRESHOLD	3
 
-#define CPCAP_ADC_MAX_RETRIES		5	/* Calibration and quirk */
+#define CPCAP_ADC_MAX_RETRIES		5	/* Calibration */
 
 /**
  * struct cpcap_adc_ato - timing settings for cpcap adc

@@ -635,27 +635,6 @@ static void cpcap_adc_setup_bank(struct cpcap_adc *ddata,
 	}
 }
 
-/*
- * Occasionally the ADC does not seem to start and there will be no
- * interrupt. Let's re-init interrupt to prevent the ADC from hanging
- * for the next request. It is unclear why this happens, but the next
- * request will usually work after doing this.
- */
-static void cpcap_adc_quirk_reset_lost_irq(struct cpcap_adc *ddata)
-{
-	int error;
-
-	dev_info(ddata->dev, "lost ADC irq, attempting to reinit\n");
-	disable_irq(ddata->irq);
-	error = regmap_update_bits(ddata->reg, CPCAP_REG_ADCC2,
-				   CPCAP_BIT_ADTRIG_DIS,
-				   CPCAP_BIT_ADTRIG_DIS);
-	if (error)
-		dev_warn(ddata->dev, "%s reset failed: %i\n",
-			 __func__, error);
-	enable_irq(ddata->irq);
-}
-
 static int cpcap_adc_start_bank(struct cpcap_adc *ddata,
 				struct cpcap_adc_request *req)
 {

@@ -673,7 +652,6 @@ static int cpcap_adc_start_bank(struct cpcap_adc *ddata,
 			return 0;
 
 		if (error == 0) {
-			cpcap_adc_quirk_reset_lost_irq(ddata);
 			error = -ETIMEDOUT;
 			continue;
 		}