[PATCH v2 0/7] Add support for magnetometer Yamaha YAS537

[PATCH v2 0/7] Add support for magnetometer Yamaha YAS537

[Jakob Hauser]

This patchset adds YAS537 variant to the already existing driver for
Yamaha YAS magnetometers.

Patch 1 is a fix on the current driver.
Patches 2-6 are cleanups and refactoring.
Patch 7 finally adds the YAS537 variant.

Changes in v2:
 - Reordered the patchset by moving patch 4 v1 to patch 1 v2.
 - Removed patch 6 v1 ("Remove redundant defaults on switch devid")
 - Accordingly, added "default:" to each switch statement in patch 7.
 - Moved renamings in patch 7 v1 into a separate new patch 6 v2. I added
   the "Reviewed-by:" tag of Linus to both patches, hope that's ok, else
   feel free to comment.
 - Removed regmap reads and related debug dumps in patch 7 in function
   yas537_dump_calibration(). As this function now applies to version 1
   only, replaced switch statement by if clause.
 - Also removed "hard_offsets" debug dumps in that function.
 - Fixed typo "initialized" in commit message of patch 7.

Jakob Hauser (7):
  iio: magnetometer: yas530: Change data type of hard_offsets to signed
  iio: magnetometer: yas530: Change range of data in volatile register
  iio: magnetometer: yas530: Correct scaling of magnetic axes
  iio: magnetometer: yas530: Correct temperature handling
  iio: magnetometer: yas530: Change data type of calibration
    coefficients
  iio: magnetometer: yas530: Rename functions and registers
  iio: magnetometer: yas530: Add YAS537 variant

 drivers/iio/magnetometer/Kconfig         |   4 +-
 drivers/iio/magnetometer/yamaha-yas530.c | 790 +++++++++++++++++++----
 2 files changed, 684 insertions(+), 110 deletions(-)

-- 
2.35.1

[PATCH v2 1/7] iio: magnetometer: yas530: Change data type of hard_offsets to signed

[Jakob Hauser]

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 <linus.walleij@linaro.org>
Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
 drivers/iio/magnetometer/yamaha-yas530.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/magnetometer/yamaha-yas530.c b/drivers/iio/magnetometer/yamaha-yas530.c
index 9ff7b0e56cf6..b58a9c51e9ff 100644
--- a/drivers/iio/magnetometer/yamaha-yas530.c
+++ b/drivers/iio/magnetometer/yamaha-yas530.c
@@ -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];
-- 
2.35.1

[PATCH v2 2/7] iio: magnetometer: yas530: Change range of data in volatile register

[Jakob Hauser]

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 <linus.walleij@linaro.org>
Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/iio/magnetometer/yamaha-yas530.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/magnetometer/yamaha-yas530.c b/drivers/iio/magnetometer/yamaha-yas530.c
index b58a9c51e9ff..2d71ae837bf5 100644
--- a/drivers/iio/magnetometer/yamaha-yas530.c
+++ b/drivers/iio/magnetometer/yamaha-yas530.c
@@ -527,7 +527,7 @@ static bool yas5xx_volatile_reg(struct device *dev, unsigned int reg)
 {
 	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);
 }
 
 /* TODO: enable regmap cache, using mark dirty and sync at runtime resume */
-- 
2.35.1

[PATCH v2 3/7] iio: magnetometer: yas530: Correct scaling of magnetic axes

[Jakob Hauser]

Looks like YAS530 raw values return picotesla and YAS532 nanotesla. Adapt
comments and scaling.

Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/iio/magnetometer/yamaha-yas530.c | 28 +++++++++++++++---------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/magnetometer/yamaha-yas530.c b/drivers/iio/magnetometer/yamaha-yas530.c
index 2d71ae837bf5..40c81c082782 100644
--- a/drivers/iio/magnetometer/yamaha-yas530.c
+++ b/drivers/iio/magnetometer/yamaha-yas530.c
@@ -310,8 +310,6 @@ static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis)
  * @yo: Y axis out
  * @zo: Z axis out
  * @return: 0 on success or error code
- *
- * Returned values are in nanotesla according to some code.
  */
 static int yas5xx_get_measure(struct yas5xx *yas5xx, s32 *to, s32 *xo, s32 *yo, s32 *zo)
 {
@@ -417,14 +415,24 @@ static int yas5xx_read_raw(struct iio_dev *indio_dev,
 			*val = 1;
 			return IIO_VAL_INT;
 		}
-		/*
-		 * The axis values are in nanotesla according to the vendor
-		 * drivers, but is clearly in microtesla according to
-		 * experiments. Since 1 uT = 0.01 Gauss, we need to divide
-		 * by 100000000 (10^8) to get to Gauss from the raw value.
-		 */
-		*val = 1;
-		*val2 = 100000000;
+		switch (yas5xx->devid) {
+		case YAS530_DEVICE_ID:
+			/*
+			 * Raw values of YAS530 are in picotesla. Devide by
+			 * 100000000 (10^8) to get Gauss.
+			 */
+			*val = 1;
+			*val2 = 100000000;
+			break;
+		case YAS532_DEVICE_ID:
+			/*
+			 * Raw values of YAS532 are in nanotesla. Devide by
+			 * 100000 (10^5) to get Gauss.
+			 */
+			*val = 1;
+			*val2 = 100000;
+			break;
+		}
 		return IIO_VAL_FRACTIONAL;
 	default:
 		/* Unknown request */
-- 
2.35.1

[PATCH v2 4/7] iio: magnetometer: yas530: Correct temperature handling

[Jakob Hauser]

The raw temperature value is a number of counts from a certain starting
point. The resolution of the temperature counts is different for the YAS
variants.

Temperature compensation for YAS532 version AC seems to be handled differently.
It uses the deviation from 20 degree Celsius [1] whereas YAS530 and older
versions of YAS532 apply solely the t value as a multiplier [2][3].

In funtion yas5xx_read_raw(), add case IIO_CHAN_INFO_PROCESSED. Remove scale
of temperature as this isn't applied.

Additionally correct sign of temperature channel in iio_chan_spec. It's already
defined that way in yas5xx_get_measure() function.

[1] https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas532.c#L442
[2] https://github.com/NovaFusion/android_kernel_samsung_golden/blob/cm-12.1/drivers/sensor/compass/yas_mag_driver-yas530.c#L881-L883
[3] https://github.com/LineageOS/android_kernel_samsung_msm8930-common/blob/lineage-18.1/drivers/sensors/geomagnetic/yas_mag_driver-yas53x.c#L856-L858

Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/iio/magnetometer/yamaha-yas530.c | 93 ++++++++++++++++++------
 1 file changed, 70 insertions(+), 23 deletions(-)

diff --git a/drivers/iio/magnetometer/yamaha-yas530.c b/drivers/iio/magnetometer/yamaha-yas530.c
index 40c81c082782..9bfb3b573907 100644
--- a/drivers/iio/magnetometer/yamaha-yas530.c
+++ b/drivers/iio/magnetometer/yamaha-yas530.c
@@ -77,6 +77,7 @@
 #define YAS530_DATA_BITS		12
 #define YAS530_DATA_CENTER		BIT(YAS530_DATA_BITS - 1)
 #define YAS530_DATA_OVERFLOW		(BIT(YAS530_DATA_BITS) - 1)
+#define YAS530_20DEGREES		182 /* Counts starting at -62 °C */
 
 #define YAS532_DEVICE_ID		0x02 /* YAS532/YAS533 (MS-3R/F) */
 #define YAS532_VERSION_AB		0 /* YAS532/533 AB (MS-3R/F AB) */
@@ -88,7 +89,7 @@
 #define YAS532_DATA_BITS		13
 #define YAS532_DATA_CENTER		BIT(YAS532_DATA_BITS - 1)
 #define YAS532_DATA_OVERFLOW		(BIT(YAS532_DATA_BITS) - 1)
-#define YAS532_20DEGREES		390 /* Looks like Kelvin */
+#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) */
@@ -314,7 +315,7 @@ static s32 yas5xx_linearize(struct yas5xx *yas5xx, u16 val, int axis)
 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 +330,43 @@ 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
-	 * 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;
+		break;
+	case YAS532_DEVICE_ID:
+		t_ref = YAS532_20DEGREES;
+		break;
+	}
+
+	/* Temperature compensation for x, y1, y2 respectively */
+	if (yas5xx->devid == YAS532_DEVICE_ID &&
+	    yas5xx->version == YAS532_VERSION_AC) {
+		/*
+		 * YAS532 version AC uses the temperature deviation as a
+		 * multiplier.
+		 *
+		 *          Cx * (t - t_ref)
+		 * x' = x - ----------------
+		 *                100
+		 */
+		sx = sx - (c->Cx * (t - t_ref)) / 100;
+		sy1 = sy1 - (c->Cy1 * (t - t_ref)) / 100;
+		sy2 = sy2 - (c->Cy2 * (t - t_ref)) / 100;
+	} 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 +375,34 @@ 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
-	 * 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 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).
+		 *
+		 * 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;
+	}
+
 	/*
 	 * Calibrate [x,y,z] with some formulas like this:
 	 *
@@ -384,6 +435,7 @@ 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 +462,6 @@ 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 +560,7 @@ 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,
-- 
2.35.1

Re: [PATCH v2 4/7] iio: magnetometer: yas530: Correct temperature handling

[Andy Shevchenko]

On Mon, Jun 13, 2022 at 3:17 AM Jakob Hauser <jahau@rocketmail.com> wrote:
>
> The raw temperature value is a number of counts from a certain starting
> point. The resolution of the temperature counts is different for the YAS
> variants.
>
> Temperature compensation for YAS532 version AC seems to be handled differently.
> It uses the deviation from 20 degree Celsius [1] whereas YAS530 and older
> versions of YAS532 apply solely the t value as a multiplier [2][3].
>
> In funtion yas5xx_read_raw(), add case IIO_CHAN_INFO_PROCESSED. Remove scale
> of temperature as this isn't applied.
>
> Additionally correct sign of temperature channel in iio_chan_spec. It's already
> defined that way in yas5xx_get_measure() function.

in the

...

Please add default cases into switches.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 4/7] iio: magnetometer: yas530: Correct temperature handling

[Jakob Hauser]

Hi Andy,

On 13.06.22 17:01, Andy Shevchenko wrote:
>
> Please add default cases into switches.

Oh, I forgot these. I'll add them.

Kind regards,
Jakob

[PATCH v2 5/7] iio: magnetometer: yas530: Change data type of calibration coefficients

[Jakob Hauser]

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 <linus.walleij@linaro.org>
Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/iio/magnetometer/yamaha-yas530.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/magnetometer/yamaha-yas530.c b/drivers/iio/magnetometer/yamaha-yas530.c
index 9bfb3b573907..31637a890b7f 100644
--- a/drivers/iio/magnetometer/yamaha-yas530.c
+++ b/drivers/iio/magnetometer/yamaha-yas530.c
@@ -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;
 };
-- 
2.35.1

[PATCH v2 6/7] iio: magnetometer: yas530: Rename functions and registers

[Jakob Hauser]

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 <linus.walleij@linaro.org>
Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/iio/magnetometer/yamaha-yas530.c | 106 ++++++++++++-----------
 1 file changed, 55 insertions(+), 51 deletions(-)

diff --git a/drivers/iio/magnetometer/yamaha-yas530.c b/drivers/iio/magnetometer/yamaha-yas530.c
index 31637a890b7f..72958bc0849b 100644
--- a/drivers/iio/magnetometer/yamaha-yas530.c
+++ b/drivers/iio/magnetometer/yamaha-yas530.c
@@ -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
-#define YAS5XX_OFFSET_X			0x85 /* [-31 .. 31] */
-#define YAS5XX_OFFSET_Y1		0x86 /* [-31 .. 31] */
-#define YAS5XX_OFFSET_Y2		0x87 /* [-31 .. 31] */
-#define YAS5XX_TEST1			0x88
-#define YAS5XX_TEST2			0x89
-#define YAS5XX_CAL			0x90
 #define YAS5XX_MEASURE_DATA		0xB0
 
+/* Registers used by YAS530 and YAS532 */
+#define YAS530_532_ACTUATE_INIT_COIL	0x81
+#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
@@ -190,7 +192,8 @@ static u16 yas532_extract_axis(u8 *data)
  * @y2: the y2 axis measurement
  * @return: 0 on success or error code
  */
-static int yas5xx_measure(struct yas5xx *yas5xx, u16 *t, u16 *x, u16 *y1, u16 *y2)
+static int yas530_532_measure(struct yas5xx *yas5xx, u16 *t,
+			      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) {
@@ -596,11 +600,11 @@ 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);
 
@@ -638,12 +642,12 @@ 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);
@@ -655,7 +659,7 @@ 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:
@@ -686,11 +690,11 @@ 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);
@@ -709,7 +713,7 @@ 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:
@@ -732,7 +736,7 @@ 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;
 
@@ -755,20 +759,20 @@ 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);
@@ -777,7 +781,7 @@ 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;
@@ -786,7 +790,7 @@ 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;
 
@@ -820,26 +824,26 @@ 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;
 
@@ -848,27 +852,27 @@ 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,
@@ -950,11 +954,11 @@ 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;
 
-- 
2.35.1

[PATCH v2 7/7] iio: magnetometer: yas530: Add YAS537 variant

[Jakob Hauser]

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 <linus.walleij@linaro.org>
Signed-off-by: Jakob Hauser <jahau@rocketmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
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_v2/drivers/iio/magnetometer/yamaha-yas530.c#L1413-L1462

 drivers/iio/magnetometer/Kconfig         |   4 +-
 drivers/iio/magnetometer/yamaha-yas530.c | 569 +++++++++++++++++++++--
 2 files changed, 543 insertions(+), 30 deletions(-)

diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
index 07eb619bcfe8..868128cee835 100644
--- a/drivers/iio/magnetometer/Kconfig
+++ b/drivers/iio/magnetometer/Kconfig
@@ -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.
 
 	  This driver can also be compiled as a module.
 	  To compile this driver as a module, choose M here: the module
diff --git a/drivers/iio/magnetometer/yamaha-yas530.c b/drivers/iio/magnetometer/yamaha-yas530.c
index 72958bc0849b..10b87bffccae 100644
--- a/drivers/iio/magnetometer/yamaha-yas530.c
+++ b/drivers/iio/magnetometer/yamaha-yas530.c
@@ -10,13 +10,16 @@
  * (YAS534 is a magnetic switch, not handled)
  * YAS535 MS-6C
  * YAS536 MS-3W
- * YAS537 MS-3T (2015 Samsung Galaxy S6, Note 5, Xiaomi)
+ * YAS537 MS-3T (2015 Samsung Galaxy S6, Note 5, Galaxy S7)
  * YAS539 MS-3S (2018 Samsung Galaxy A7 SM-A750FN)
  *
  * Code functions found in the MPU3050 YAS530 and YAS532 drivers
  * 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 <linus.walleij@linaro.org>
  */
 #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) /* corresponds to 0x70 */
+#define YAS537_MEASURE_TIME_WORST	1500 /* us */
+#define YAS537_DEFAULT_SENSOR_DELAY	50   /* ms */
+#define YAS537_MAG_RCOIL_TIME		65   /* us */
+#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 +295,84 @@ 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;
+	}
+
+	/* Read data */
+	ret = regmap_bulk_read(yas5xx->map, YAS5XX_MEASURE_DATA,
+			       data, sizeof(data));
+	if (ret)
+		goto out_unlock;
+
+	mutex_unlock(&yas5xx->lock);
+
+	/* Arrange data */
+	*t = ((data[0] << 8) | data[1]);
+	xy1y2[0] = ((FIELD_GET(GENMASK(5, 0), data[2]) << 8) | data[3]);
+	xy1y2[1] = ((data[4] << 8) | data[5]);
+	xy1y2[2] = ((data[6] << 8) | data[7]);
+
+	/* 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] - 8192;
+		h[0] = (c->k *   (128 * s[0] + c->a2 * s[1] + c->a3 * s[2])) / 8192;
+		h[1] = (c->k * (c->a4 * s[0] + c->a5 * s[1] + c->a6 * s[2])) / 8192;
+		h[2] = (c->k * (c->a7 * s[0] + c->a8 * s[1] + c->a9 * s[2])) / 8192;
+		for (i = 0; i < 3; i++) {
+			if (h[i] < -8192)
+				h[i] = -8192;
+			if (h[i] > 8191)
+				h[i] = 8191;
+			xy1y2[i] = h[i] + 8192;
+		}
+	}
+
+	/* Assign data */
+	*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;
@@ -322,7 +428,7 @@ static int yas530_532_get_measure(struct yas5xx *yas5xx, s32 *to,
 {
 	struct yas5xx_calibration *c = &yas5xx->calibration;
 	u16 t_ref, t, x, y1, y2;
-	/* These are "signed x, signed y1 etc */
+	/* These are signed x, signed y1 etc */
 	s32 sx, sy1, sy2, sy, sz;
 	int ret;
 
@@ -431,6 +537,57 @@ 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 number of counts. A product description
+	 * of YAS537 mentions a temperature resulution 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 - 8192) * 300;
+	*yo = (y1 - y2) * 1732 / 10;
+	*zo = (-y1 - y2 + 16384) * 300;
+
+	return 0;
+}
+
 static int yas5xx_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val, int *val2,
@@ -444,7 +601,18 @@ 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);
-		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);
+			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)
@@ -478,9 +646,10 @@ 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. Devide by
-			 * 100000 (10^5) to get Gauss.
+			 * Raw values of YAS532 and YAS537 are in nanotesla.
+			 * Devide by 100000 (10^5) to get Gauss.
 			 */
 			*val = 1;
 			*val2 = 100000;
@@ -500,7 +669,18 @@ static void yas5xx_fill_buffer(struct iio_dev *indio_dev)
 	int ret;
 
 	pm_runtime_get_sync(yas5xx->dev);
-	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);
+		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) {
@@ -586,9 +766,34 @@ 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 ||
-		(reg >= YAS5XX_MEASURE_DATA && reg <= YAS5XX_MEASURE_DATA + 7);
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct yas5xx *yas5xx = iio_priv(indio_dev);
+
+	if (reg >= YAS5XX_MEASURE_DATA && reg <= YAS5XX_MEASURE_DATA + 7)
+		return true;
+
+	/*
+	 * YAS versions share different registers on the same address,
+	 * need to differentiate.
+	 */
+	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 */
@@ -652,7 +857,10 @@ static int yas530_get_calibration_data(struct yas5xx *yas5xx)
 		return ret;
 	dev_dbg(yas5xx->dev, "calibration data: %*ph\n", 14, data);
 
+	/* Contribute calibration data to the input pool for kernel entropy */
 	add_device_randomness(data, sizeof(data));
+
+	/* Extract version */
 	yas5xx->version = data[15] & GENMASK(1, 0);
 
 	/* Extract the calibration from the bitfield */
@@ -679,6 +887,7 @@ static int yas530_get_calibration_data(struct yas5xx *yas5xx)
 	c->r[0] = sign_extend32(FIELD_GET(GENMASK(28, 23), val), 5);
 	c->r[1] = sign_extend32(FIELD_GET(GENMASK(20, 15), val), 5);
 	c->r[2] = sign_extend32(FIELD_GET(GENMASK(12, 7), val), 5);
+
 	return 0;
 }
 
@@ -705,7 +914,9 @@ static int yas532_get_calibration_data(struct yas5xx *yas5xx)
 			dev_warn(yas5xx->dev, "calibration is blank!\n");
 	}
 
+	/* Contribute calibration data to the input pool for kernel entropy */
 	add_device_randomness(data, sizeof(data));
+
 	/* Only one bit of version info reserved here as far as we know */
 	yas5xx->version = data[13] & BIT(0);
 
@@ -714,6 +925,7 @@ static int yas532_get_calibration_data(struct yas5xx *yas5xx)
 	c->Cy1 = data[1] * 10 - 1280;
 	c->Cy2 = data[2] * 10 - 1280;
 	yas530_532_extract_calibration(&data[3], c);
+
 	/*
 	 * Extract linearization:
 	 * Linearization layout in the 32 bits at byte 10:
@@ -736,6 +948,216 @@ 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: %*ph\n", 17, data);
+
+	/* Sanity check, is this all zeroes? */
+	if (memchr_inv(data, 0x00, 16) == NULL) {
+		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]);
+
+	/* There are two versions of YAS537 behaving differently */
+	switch (yas5xx->version) {
+
+	case YAS537_VERSION_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
+		 *
+		 * 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++) {
+			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
+		 */
+
+		ret = regmap_write(yas5xx->map, YAS537_MTC + 3,
+				   ((data[3] & GENMASK(7, 5)) | BIT(4)));
+		if (ret)
+			return ret;
+		ret = regmap_write(yas5xx->map, YAS537_HCK,
+				   (FIELD_GET(GENMASK(7, 4), data[15]) << 1));
+		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 three blocks val1 to val3 */
+		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;
@@ -759,6 +1181,26 @@ 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;
@@ -875,6 +1317,43 @@ static int yas530_532_power_on(struct yas5xx *yas5xx)
 	return regmap_write(yas5xx->map, YAS530_532_MEASURE_INTERVAL, 0);
 }
 
+static int yas537_power_on(struct yas5xx *yas5xx)
+{
+	int ret;
+	u8 intrvl;
+
+	/* Write registers according to Android driver */
+	ret = regmap_write(yas5xx->map, YAS537_ADCCAL, GENMASK(1, 0));
+	if (ret)
+		return ret;
+	ret = regmap_write(yas5xx->map, YAS537_ADCCAL+1, GENMASK(7, 3));
+	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 * 1000
+		 - YAS537_MEASURE_TIME_WORST) / 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;
+	usleep_range(YAS537_MAG_RCOIL_TIME, YAS537_MAG_RCOIL_TIME+100);
+
+	return 0;
+}
+
 static int yas5xx_probe(struct i2c_client *i2c,
 			const struct i2c_device_id *id)
 {
@@ -933,35 +1412,55 @@ static int yas5xx_probe(struct i2c_client *i2c,
 
 	switch (yas5xx->devid) {
 	case YAS530_DEVICE_ID:
-		ret = yas530_get_calibration_data(yas5xx);
+	case YAS532_DEVICE_ID:
+
+		if (yas5xx->devid == YAS530_DEVICE_ID) {
+			ret = yas530_get_calibration_data(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));
+		} 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");
+		/* As the version naming is unknown, provide it for debug only */
+		dev_dbg(yas5xx->dev, "YAS537 version: %s\n",
+			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;
-
 	indio_dev->info = &yas5xx_info;
 	indio_dev->available_scan_masks = yas5xx_scan_masks;
 	indio_dev->modes = INDIO_DIRECT_MODE;
@@ -1057,7 +1556,19 @@ static int __maybe_unused yas5xx_runtime_resume(struct device *dev)
 	usleep_range(31000, 40000);
 	gpiod_set_value_cansleep(yas5xx->reset, 0);
 
-	ret = yas5xx_power_on(yas5xx);
+	switch (yas5xx->devid) {
+	case YAS530_DEVICE_ID:
+	case YAS532_DEVICE_ID:
+		ret = yas530_532_power_on(yas5xx);
+		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;
@@ -1083,6 +1594,7 @@ static const struct i2c_device_id yas5xx_id[] = {
 	{"yas530", },
 	{"yas532", },
 	{"yas533", },
+	{"yas537", },
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, yas5xx_id);
@@ -1091,6 +1603,7 @@ static const struct of_device_id yas5xx_of_match[] = {
 	{ .compatible = "yamaha,yas530", },
 	{ .compatible = "yamaha,yas532", },
 	{ .compatible = "yamaha,yas533", },
+	{ .compatible = "yamaha,yas537", },
 	{}
 };
 MODULE_DEVICE_TABLE(of, yas5xx_of_match);
-- 
2.35.1

Re: [PATCH v2 7/7] iio: magnetometer: yas530: Add YAS537 variant

[Andy Shevchenko]

On Mon, Jun 13, 2022 at 3:18 AM Jakob Hauser <jahau@rocketmail.com> wrote:
>
> 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.

...

> - * YAS537 MS-3T (2015 Samsung Galaxy S6, Note 5, Xiaomi)
> + * YAS537 MS-3T (2015 Samsung Galaxy S6, Note 5, Galaxy S7)

Not sure what happened to Xiaomi. There is nothing in the commit
message about this change.

...

> +#define YAS537_MAG_AVERAGE_32_MASK     GENMASK(6, 4) /* corresponds to 0x70 */

Useless comment.

...

> +#define YAS537_MEASURE_TIME_WORST      1500 /* us */
> +#define YAS537_DEFAULT_SENSOR_DELAY    50   /* ms */
> +#define YAS537_MAG_RCOIL_TIME          65   /* us */

Instead of the comments, use unit suffixes, i.e. _US, _MS, _US.

...

> +       /* Read data */

Not sure how useful is this comment.

...

> +       *t = ((data[0] << 8) | data[1]);

Looks like get_unaligned_be16().

> +       xy1y2[0] = ((FIELD_GET(GENMASK(5, 0), data[2]) << 8) | data[3]);
> +       xy1y2[1] = ((data[4] << 8) | data[5]);
> +       xy1y2[2] = ((data[6] << 8) | data[7]);

Ditto for all above.

...

> +                       if (h[i] < -8192)
> +                               h[i] = -8192;

-BIT(13) ?

> +                       if (h[i] > 8191)
> +                               h[i] = 8191;

Altogether seems like NIH clamp_val() or clamp_t().

...

> +                       xy1y2[i] = h[i] + 8192;

BIT(13)

...

> +       /*
> +        * Raw temperature value t is number of counts. A product description
> +        * of YAS537 mentions a temperature resulution of 0.05 °C/count.

resolution

> +        * 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.
> +        */

...

>                         /*
> -                        * Raw values of YAS532 are in nanotesla. Devide by
> -                        * 100000 (10^5) to get Gauss.
> +                        * Raw values of YAS532 and YAS537 are in nanotesla.
> +                        * Devide by 100000 (10^5) to get Gauss.

Divide (chance to fix a type while at it)

>                          */

...

> @@ -679,6 +887,7 @@ static int yas530_get_calibration_data(struct yas5xx *yas5xx)
>         c->r[0] = sign_extend32(FIELD_GET(GENMASK(28, 23), val), 5);
>         c->r[1] = sign_extend32(FIELD_GET(GENMASK(20, 15), val), 5);
>         c->r[2] = sign_extend32(FIELD_GET(GENMASK(12, 7), val), 5);
> +
>         return 0;
>  }
>

Not harmful, but a stray change. Ditto for the rest like this. I would
rather split them to a separate patch.

...

> +       dev_dbg(yas5xx->dev, "calibration data: %*ph\n", 17, data);

Use less stack by "%17ph".

...

> +       /* Sanity check, is this all zeroes? */
> +       if (memchr_inv(data, 0x00, 16) == NULL) {

  if (!memchr_inv(...))

> +               if (FIELD_GET(GENMASK(5, 0), data[16]) == 0)
> +                       dev_warn(yas5xx->dev, "calibration is blank!\n");
> +       }

...

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

16 and 17 seems like a magic that is used a lot, perhaps define?

...

> +               ret = regmap_write(yas5xx->map, YAS537_MTC + 3,
> +                                  ((data[3] & GENMASK(7, 5)) | BIT(4)));

Here...

> +               if (ret)
> +                       return ret;
> +               ret = regmap_write(yas5xx->map, YAS537_HCK,
> +                                  (FIELD_GET(GENMASK(7, 4), data[15]) << 1));

...and here and in many other places, please drop outer parentheses,
they are not needed.

> +               if (ret)
> +                       return ret;

...

> +       usleep_range(YAS537_MAG_RCOIL_TIME, YAS537_MAG_RCOIL_TIME+100);

Please, add a comment explaining why this is needed.

...

> +               dev_info(dev, "detected YAS537 MS-3T");
> +               /* As the version naming is unknown, provide it for debug only */
> +               dev_dbg(yas5xx->dev, "YAS537 version: %s\n",
> +                       yas5xx->version ? "1" : "0");

No need to have two prints, just add a version to the above one and
drop the bottom one.


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 7/7] iio: magnetometer: yas530: Add YAS537 variant

[Andy Shevchenko]

On Mon, Jun 13, 2022 at 5:20 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Mon, Jun 13, 2022 at 3:18 AM Jakob Hauser <jahau@rocketmail.com> wrote:

Forgot to add that please try to split even more preparatory patches.
For example, you may convert existing code to stubs / switch-cases /
etc and in the last patch just add the new case or new function /
branch.

...

> > +       /*
> > +        * Raw temperature value t is number of counts. A product description

the number

> > +        * of YAS537 mentions a temperature resulution of 0.05 °C/count.
>
> resolution
>
> > +        * 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.
> > +        */

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 7/7] iio: magnetometer: yas530: Add YAS537 variant

[Jakob Hauser]

Hi Andy,

On 13.06.22 17:22, Andy Shevchenko wrote:
>
> Forgot to add that please try to split even more preparatory patches.
> For example, you may convert existing code to stubs / switch-cases /
> etc and in the last patch just add the new case or new function /
> branch.

That's a good idea. I had a closer look. But I can't spot something that
could be beneficial.

The new functions for YAS537 are similar in structure like their
counterparts of YAS530/YAS532. However, in detail they differ too much,
which hinders merging them into each other.

yas537_measure() being different to yas530_532_measure():
 - regmap_write() has an additional bit YAS5XX_MEASURE_CONT
 - regmap_read_poll_timeout() differs in the read location
 - calculating the values t, x, y1 and y2 are different

yas537_get_measure() being different to yas530_532_get_measure():
 - no linearization
 - no temperature compensation
 - different way of calculating x, y, z from x, y1, y2

yas537_get_calibration_data() being different to
yas530.../yas532_get_calibration_data():
 - one regmap_bulk_read() only
 - different way of getting or extracting the calibration data

yas537_power_on()
 - different procedure and registers

The function yas537_dump_calibration() shares a notable part with
yas530_532_dump_calibration() after the changes applied in patchset v2.
Although merging them together would need some "if" or "switch"
statements because YAS537 version 0 needs to be excluded from that
function and YAS537 version 1 would need to be excluded from the first
and last part of that function. I would leave it like it is, it's easier
readable.

Another approach could be to outsource some parts, which are used by all
variants, into separate functions. But again I don't see much beneficial
pars here.

In yas537_measure() and yas530_532_measure() it could be:
 - regmap_bulk_read()

In yas537_get_calibration_data() and
yas530.../yas532_get_calibration_data() it could be:
 - add_device_randomness()

I think that's it. Both are too small for being worth outsourcing into a
separate function.

Kind regards,
Jakob

Re: [PATCH v2 7/7] iio: magnetometer: yas530: Add YAS537 variant

[Jakob Hauser]

Hi Andy,

again on the Cc list, sorry: Looks like the part...

"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS
<devicetree@vger.kernel.org>, Hans de Goede <hdegoede@redhat.com>, Andy
Shevchenko <andy.shevchenko@gmail.com>,"

... as a text string is saved in your e-mail clients' address book as
the name of the e-mail address <~postmarketos/upstreaming@lists.sr.ht>.

On 13.06.22 17:20, Andy Shevchenko wrote:
>
> On Mon, Jun 13, 2022 at 3:18 AM Jakob Hauser <jahau@rocketmail.com> wrote:
>>
>> - * YAS537 MS-3T (2015 Samsung Galaxy S6, Note 5, Xiaomi)
>> + * YAS537 MS-3T (2015 Samsung Galaxy S6, Note 5, Galaxy S7)
> 
> Not sure what happened to Xiaomi. There is nothing in the commit
> message about this change.

"Xiaomi" is too generic, specific devices should be listed here. E.g.
Xiaomi Redmi 2 seems to have YAS537 but I'm fully sure this applies to
all its variants [1]. Samsung Galaxy S7 (and S7 edge) is often quoted in
conjunction with YAS537, so I took this.

Further down you suggested to move stray changes into a separate patch.
I'll move this one too.

[1] https://en.wikipedia.org/wiki/Redmi_2#Variants

>> +#define YAS537_MAG_AVERAGE_32_MASK     GENMASK(6, 4) /* corresponds to 0x70 */
> 
> Useless comment.

The comment is related to the values in the Yamaha Android driver [2].
It depends on the "average" to be chosen [3], "YAS537_MAG_AVERAGE_32" is
used for regular operation [4]. As this isn't easily comprehensible on
the first sight, I added that comment.

Within the mainline driver, the comment is not necessarily needed. Will
remove it.

[2]
https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas537.c#L258
[3]
https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas537.c#L63-L68
[4]
https://github.com/msm8916-mainline/android_kernel_qcom_msm8916/blob/GT-I9195I/drivers/iio/magnetometer/yas_mag_drv-yas537.c#L748

>> +#define YAS537_MEASURE_TIME_WORST      1500 /* us */
>> +#define YAS537_DEFAULT_SENSOR_DELAY    50   /* ms */
>> +#define YAS537_MAG_RCOIL_TIME          65   /* us */
> 
> Instead of the comments, use unit suffixes, i.e. _US, _MS, _US.

OK, thanks for the hint.

>> +       /* Read data */
> 
> Not sure how useful is this comment.

It's part of the "process description": Read data, Arrange data, Assign
data. Maybe I've overdone the commenting here, I'll remove those three
comments.

>> +       *t = ((data[0] << 8) | data[1]);
> 
> Looks like get_unaligned_be16().
> 
>> +       xy1y2[0] = ((FIELD_GET(GENMASK(5, 0), data[2]) << 8) | data[3]);
>> +       xy1y2[1] = ((data[4] << 8) | data[5]);
>> +       xy1y2[2] = ((data[6] << 8) | data[7]);
> 
> Ditto for all above.

Ah, I wasn't aware about using this here. Will apply.

>> +                       if (h[i] < -8192)
>> +                               h[i] = -8192;
> 
> -BIT(13) ?
> 
>> +                       if (h[i] > 8191)
>> +                               h[i] = 8191;
> 
> Altogether seems like NIH clamp_val() or clamp_t().

I didn't know, thanks. I will change...

if (h[i] < -8192)
        h[i] = -8192;
if (h[i] > 8191)
        h[i] = 8191;

... into:

clamp_val(h[i], -BIT(13), BIT(13) - 1);

>> +                       xy1y2[i] = h[i] + 8192;
> 
> BIT(13)

Hm, if doing it here, it probably should be done for the whole
paragraph. In that case...

for (i = 0; i < 3; i++)
        s[i] = xy1y2[i] - 8192;
h[0] = (c->k *   (128 * s[0] + c->a2 * s[1] + c->a3 * s[2])) / 8192;
h[1] = (c->k * (c->a4 * s[0] + c->a5 * s[1] + c->a6 * s[2])) / 8192;
h[2] = (c->k * (c->a7 * s[0] + c->a8 * s[1] + c->a9 * s[2])) / 8192;
for (i = 0; i < 3; i++) {
        if (h[i] < -8192)
                h[i] = -8192;
if (h[i] > 8191)
                h[i] = 8191;
        xy1y2[i] = h[i] + 8192;
}

... would become:

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);
}

Further down in function yas537_get_measure(), there is another part...

*xo = (x - 8192) * 300;
*yo = (y1 - y2) * 1732 / 10;
*zo = (-y1 - y2 + 16384) * 300;

... that could be changed accordingly to:

*xo = (x - BIT(13)) * 300;
*yo = (y1 - y2) * 1732 / 10;
*zo = (-y1 - y2 + BIT(14)) * 300;

Overall for me it's harder to read that way. But maybe I'm just not used
to it.

>> @@ -679,6 +887,7 @@ static int yas530_get_calibration_data(struct yas5xx *yas5xx)
>>         c->r[0] = sign_extend32(FIELD_GET(GENMASK(28, 23), val), 5);
>>         c->r[1] = sign_extend32(FIELD_GET(GENMASK(20, 15), val), 5);
>>         c->r[2] = sign_extend32(FIELD_GET(GENMASK(12, 7), val), 5);
>> +
>>         return 0;
>>  }
>>
> 
> Not harmful, but a stray change. Ditto for the rest like this. I would
> rather split them to a separate patch.

Makes sense to split. Though the new patch will likely get a quite
generic commit title like "minor cleanups".

>> +       dev_dbg(yas5xx->dev, "calibration data: %*ph\n", 17, data);
> 
> Use less stack by "%17ph".

OK.

There is a similar line in the current driver, will change this as well
in the new stray change patch.

In yas530_get_calibration_data() I see a little mistake, it reads 14
fields, should be 16. I'll include this little correction in the stray
change patch too.

>> +       /* Sanity check, is this all zeroes? */
>> +       if (memchr_inv(data, 0x00, 16) == NULL) {
> 
>   if (!memchr_inv(...))
> 
>> +               if (FIELD_GET(GENMASK(5, 0), data[16]) == 0)
>> +                       dev_warn(yas5xx->dev, "calibration is blank!\n");
>> +       }

No problem to change for YAS537.

At YAS530/532, there is a similar line that should be changed
accordingly. However, there is a patch by Linus that was already added
to "fixes-togreg" branch in iio.git quite a while ago [5]. The patch is
not included in torvalds/linux v5.19-rc1 or -rc2 and neither in iio.git
testing branch. So I'm unsure what I should base the patchset on if I
want to change that line. I will probably choose linux-next, as the
patch is included there and in Kconfig also patch "iio: magnetometer:
ak8974: Drop dependency on OF" is included (which on the other hand
isn't included in "fixes-togreg" branch in iio.git).

[5]
https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/commit/?h=fixes-togreg&id=bb52d3691db8cf24cea049235223f3599778f264

>> +               for (i = 0; i < 17; i++) {
> 
> 16 and 17 seems like a magic that is used a lot, perhaps define?

17 is the size of the calibration data array in YAS537. Accordingly we
work with array fields 0 to 16.

On YAS530, the calibration data array has a size of 16, therefore
working with fields 0 to 15. On YAS532 the size is 14, working with
fields 0 to 13.

I wouldn't use "define" as it is kind of defined by declaration "u8
data[17];" in YAS537 for example. We could probably make more use of
sizeof(data). E.g. the line ...

dev_dbg(yas5xx->dev, "calibration data: %*ph\n", 17, data);

... could be written as...

dev_dbg(yas5xx->dev, "calibration data: %*ph\n", sizeof(data), data);

... but we wanted to change this to %17ph anyway.

Also we could change the line...

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

... into...

        for (i = 0; i < sizeof(data); i++) {

... however, I wouldn't do that, as it makes readability worse for the
next steps,...

                if (i < 12) {
                        ...
                } else if (i < 15) {
                        ...
                } else {
                        ...
                }

... in the current implementation it's easier to see that the last one
is the remaining 15 and 16.

Summing up, I wouldn't change anything on the handling of the numbers 17
or 16.

>> +               ret = regmap_write(yas5xx->map, YAS537_MTC + 3,
>> +                                  ((data[3] & GENMASK(7, 5)) | BIT(4)));
> 
> Here...
> 
>> +               if (ret)
>> +                       return ret;
>> +               ret = regmap_write(yas5xx->map, YAS537_HCK,
>> +                                  (FIELD_GET(GENMASK(7, 4), data[15]) << 1));
> 
> ..and here and in many other places, please drop outer parentheses,
> they are not needed.

It looked too dangerous without – but thanks for the hint, I'll gladly
drop them.

>> +       usleep_range(YAS537_MAG_RCOIL_TIME, YAS537_MAG_RCOIL_TIME+100);
> 
> Please, add a comment explaining why this is needed.

OK, I'll add: "Wait until the coil has ramped up".

>> +               dev_info(dev, "detected YAS537 MS-3T");
>> +               /* As the version naming is unknown, provide it for debug only */
>> +               dev_dbg(yas5xx->dev, "YAS537 version: %s\n",
>> +                       yas5xx->version ? "1" : "0");
> 
> No need to have two prints, just add a version to the above one and
> drop the bottom one.

OK.

----------------------

I also spotted a minor mistake in function yas537_get_calibration_data()
in the following part:

        /* Get data into these three blocks val1 to val3 */
        val1 = get_unaligned_be32(&data[0]);
        val2 = get_unaligned_be32(&data[3]);
        val3 = get_unaligned_be32(&data[6]);
        val4 = get_unaligned_be32(&data[9]);

The comment isn't up to date, talking about three blocks instead of
four. I'll correct this.

Kind regards,
Jakob

Re: [PATCH v2 7/7] iio: magnetometer: yas530: Add YAS537 variant

[Jakob Hauser]

On 15.06.22 23:43, Jakob Hauser wrote:
> 
> On 13.06.22 17:20, Andy Shevchenko wrote:
>>
>> On Mon, Jun 13, 2022 at 3:18 AM Jakob Hauser <jahau@rocketmail.com> wrote:
>>>
>>> - * YAS537 MS-3T (2015 Samsung Galaxy S6, Note 5, Xiaomi)
>>> + * YAS537 MS-3T (2015 Samsung Galaxy S6, Note 5, Galaxy S7)
>>
>> Not sure what happened to Xiaomi. There is nothing in the commit
>> message about this change.
> 
> "Xiaomi" is too generic, specific devices should be listed here. E.g.
> Xiaomi Redmi 2 seems to have YAS537 but I'm fully sure this applies to
> all its variants [1]. Samsung Galaxy S7 (and S7 edge) is often quoted in
> conjunction with YAS537, so I took this.

I forgot a "not" here:

"[...] but I'm *not* fully sure this applies to all its variants [...]"

Re: [PATCH v2 7/7] iio: magnetometer: yas530: Add YAS537 variant

[Jonathan Cameron]

> 
> >> +       /* Sanity check, is this all zeroes? */
> >> +       if (memchr_inv(data, 0x00, 16) == NULL) {  
> > 
> >   if (!memchr_inv(...))
> >   
> >> +               if (FIELD_GET(GENMASK(5, 0), data[16]) == 0)
> >> +                       dev_warn(yas5xx->dev, "calibration is blank!\n");
> >> +       }  
> 
> No problem to change for YAS537.
> 
> At YAS530/532, there is a similar line that should be changed
> accordingly. However, there is a patch by Linus that was already added
> to "fixes-togreg" branch in iio.git quite a while ago [5]. The patch is
> not included in torvalds/linux v5.19-rc1 or -rc2 and neither in iio.git
> testing branch. So I'm unsure what I should base the patchset on if I
> want to change that line. I will probably choose linux-next, as the
> patch is included there and in Kconfig also patch "iio: magnetometer:
> ak8974: Drop dependency on OF" is included (which on the other hand
> isn't included in "fixes-togreg" branch in iio.git).
> 
> [5]
> https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git/commit/?h=fixes-togreg&id=bb52d3691db8cf24cea049235223f3599778f264

Busy couple of weeks for me and that fix got caught up in the merge
window timing before that.  I should get a pull request out shortly.

Jonathan

Re: [PATCH v2 0/7] Add support for magnetometer Yamaha YAS537

[Andy Shevchenko]

On Mon, Jun 13, 2022 at 3:16 AM Jakob Hauser <jahau@rocketmail.com> wrote:
>
> This patchset adds YAS537 variant to the already existing driver for
> Yamaha YAS magnetometers.
>
> Patch 1 is a fix on the current driver.
> Patches 2-6 are cleanups and refactoring.
> Patch 7 finally adds the YAS537 variant.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
for patches 2-6.
Patch 1 is already reviewed, patch 7 needs a bit more work.

> Changes in v2:
>  - Reordered the patchset by moving patch 4 v1 to patch 1 v2.
>  - Removed patch 6 v1 ("Remove redundant defaults on switch devid")
>  - Accordingly, added "default:" to each switch statement in patch 7.
>  - Moved renamings in patch 7 v1 into a separate new patch 6 v2. I added
>    the "Reviewed-by:" tag of Linus to both patches, hope that's ok, else
>    feel free to comment.
>  - Removed regmap reads and related debug dumps in patch 7 in function
>    yas537_dump_calibration(). As this function now applies to version 1
>    only, replaced switch statement by if clause.
>  - Also removed "hard_offsets" debug dumps in that function.
>  - Fixed typo "initialized" in commit message of patch 7.

> Jakob Hauser (7):
>   iio: magnetometer: yas530: Change data type of hard_offsets to signed
>   iio: magnetometer: yas530: Change range of data in volatile register
>   iio: magnetometer: yas530: Correct scaling of magnetic axes
>   iio: magnetometer: yas530: Correct temperature handling
>   iio: magnetometer: yas530: Change data type of calibration
>     coefficients
>   iio: magnetometer: yas530: Rename functions and registers
>   iio: magnetometer: yas530: Add YAS537 variant
>
>  drivers/iio/magnetometer/Kconfig         |   4 +-
>  drivers/iio/magnetometer/yamaha-yas530.c | 790 +++++++++++++++++++----
>  2 files changed, 684 insertions(+), 110 deletions(-)
>
> --
> 2.35.1
>


-- 
With Best Regards,
Andy Shevchenko