[PATCH v2 0/2] iio: magnetometer: minor style change and add support for new chip

[PATCH v2 0/2] iio: magnetometer: minor style change and add support for new chip

[Teodora Baluta]

The first patch makes a minor style change in order to accomodate the
adding of the devices easier. The second patch adds support for mmc34160
magnetometer.

---
Changes since v1:
- split the patch at [0] in 2
- rebased on top of fixes at [1]
- reword description in Kconfig

[0] https://lkml.org/lkml/2015/6/29/171
[1] https://lkml.org/lkml/2015/7/14/439

Teodora Baluta (2):
  iio: mmc35240: minor change to improve code readibility
  iio: magnetometer: add mmc34160 magnetometer driver

 drivers/iio/magnetometer/Kconfig    |   4 +-
 drivers/iio/magnetometer/mmc35240.c | 229 ++++++++++++++++++++++++++++--------
 2 files changed, 181 insertions(+), 52 deletions(-)

-- 
1.9.1

[PATCH v2 1/2] iio: mmc35240: minor change to improve code readability

[Teodora Baluta]

This patch changes two variables to arrays to improve code readability.

Signed-off-by: Teodora Baluta <teodora.baluta@intel.com>
---
 drivers/iio/magnetometer/mmc35240.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
index 706ebfd..29b52fa 100644
--- a/drivers/iio/magnetometer/mmc35240.c
+++ b/drivers/iio/magnetometer/mmc35240.c
@@ -316,31 +316,31 @@ static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
 static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
 				  __le16 buf[], int *val)
 {
-	int raw_x, raw_y, raw_z;
-	int sens_x, sens_y, sens_z;
+	int raw[3];
+	int sens[3];
 	int nfo;
 
-	raw_x = le16_to_cpu(buf[AXIS_X]);
-	raw_y = le16_to_cpu(buf[AXIS_Y]);
-	raw_z = le16_to_cpu(buf[AXIS_Z]);
+	raw[AXIS_X] = le16_to_cpu(buf[AXIS_X]);
+	raw[AXIS_Y] = le16_to_cpu(buf[AXIS_Y]);
+	raw[AXIS_Z] = le16_to_cpu(buf[AXIS_Z]);
 
-	sens_x = mmc35240_props_table[data->res].sens[AXIS_X];
-	sens_y = mmc35240_props_table[data->res].sens[AXIS_Y];
-	sens_z = mmc35240_props_table[data->res].sens[AXIS_Z];
+	sens[AXIS_X] = mmc35240_props_table[data->res].sens[AXIS_X];
+	sens[AXIS_Y] = mmc35240_props_table[data->res].sens[AXIS_Y];
+	sens[AXIS_Z] = mmc35240_props_table[data->res].sens[AXIS_Z];
 
 	nfo = mmc35240_props_table[data->res].nfo;
 
 	switch (index) {
 	case AXIS_X:
-		*val = (raw_x - nfo) * 1000 / sens_x;
+		*val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
 		break;
 	case AXIS_Y:
-		*val = (raw_y - nfo) * 1000 / sens_y -
-			(raw_z - nfo)  * 1000 / sens_z;
+		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] -
+			(raw[AXIS_Z] - nfo)  * 1000 / sens[AXIS_Z];
 		break;
 	case AXIS_Z:
-		*val = (raw_y - nfo) * 1000 / sens_y +
-			(raw_z - nfo) * 1000 / sens_z;
+		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] +
+			(raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
 		break;
 	default:
 		return -EINVAL;
-- 
1.9.1

[PATCH v2 2/2] iio: magnetometer: add mmc34160 magnetometer driver

[Teodora Baluta]

This patch adds support for the MMC34160 3-axis magnetometer driver. The
MMC31460 magnetometer driver uses the same register map as MMC35240 with
different specifications for sensitivity.

According to Memsic specification, for the MMC31460 sensor, there is no
need to apply compensation to the read values. Also, the MMC34160 sensor
does not use the same formula as MMC35240 for transforming raw data into
mgauss, and the current formula is based on the input driver (mmc3416x)
provided by Memsic.

Signed-off-by: Teodora Baluta <teodora.baluta@intel.com>
---
 drivers/iio/magnetometer/Kconfig    |   4 +-
 drivers/iio/magnetometer/mmc35240.c | 219 ++++++++++++++++++++++++++++--------
 2 files changed, 176 insertions(+), 47 deletions(-)

diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
index efb9350..8bf2879 100644
--- a/drivers/iio/magnetometer/Kconfig
+++ b/drivers/iio/magnetometer/Kconfig
@@ -52,8 +52,8 @@ config MMC35240
 	select REGMAP_I2C
 	depends on I2C
 	help
-	  Say yes here to build support for the MEMSIC MMC35240 3-axis
-	  magnetic sensor.
+	  Say yes here to build support for the MEMSIC MMC35240 and MMC34160
+	  3-axis magnetic sensors.
 
 	  To compile this driver as a module, choose M here: the module
 	  will be called mmc35240.
diff --git a/drivers/iio/magnetometer/mmc35240.c b/drivers/iio/magnetometer/mmc35240.c
index 29b52fa..66cdf49 100644
--- a/drivers/iio/magnetometer/mmc35240.c
+++ b/drivers/iio/magnetometer/mmc35240.c
@@ -83,6 +83,20 @@
 
 #define MMC35240_OTP_START_ADDR		0x1B
 
+#define MMC35240_CHIP_ID	0x08
+#define MMC34160_CHIP_ID	0x06
+
+enum mmc35240_chipset {
+	MMC35240,
+	MMC34160,
+	MMC_MAX_CHIPS
+};
+
+static u8 chip_ids[MMC_MAX_CHIPS] = {
+	MMC35240_CHIP_ID,
+	MMC34160_CHIP_ID,
+};
+
 enum mmc35240_resolution {
 	MMC35240_16_BITS_SLOW = 0, /* 7.92 ms */
 	MMC35240_16_BITS_FAST,     /* 4.08 ms */
@@ -99,27 +113,53 @@ enum mmc35240_axis {
 static const struct {
 	int sens[3]; /* sensitivity per X, Y, Z axis */
 	int nfo; /* null field output */
-} mmc35240_props_table[] = {
-	/* 16 bits, 125Hz ODR */
+} mmc35240_props_table[MMC_MAX_CHIPS][4] = {
+	/* MMC35240 */
 	{
-		{1024, 1024, 1024},
-		32768,
+		/* 16 bits, 125Hz ODR */
+		{
+			{1024, 1024, 1024},
+			32768,
+		},
+		/* 16 bits, 250Hz ODR */
+		{
+			{1024, 1024, 770},
+			32768,
+		},
+		/* 14 bits, 450Hz ODR */
+		{
+			{256, 256, 193},
+			8192,
+		},
+		/* 12 bits, 800Hz ODR */
+		{
+			{64, 64, 48},
+			2048,
+		},
 	},
-	/* 16 bits, 250Hz ODR */
+	/* MMC34160 */
 	{
-		{1024, 1024, 770},
-		32768,
-	},
-	/* 14 bits, 450Hz ODR */
-	{
-		{256, 256, 193},
-		8192,
-	},
-	/* 12 bits, 800Hz ODR */
-	{
-		{64, 64, 48},
-		2048,
-	},
+		/* 16 bits, 125Hz ODR */
+		{
+			{2048, 2048, 2048},
+			32768,
+		},
+		/* 16 bits, 250Hz ODR */
+		{
+			{2048, 2048, 2048},
+			32768,
+		},
+		/* 14 bits, 450Hz ODR */
+		{
+			{512, 512, 512},
+			8192,
+		},
+		/* 12 bits, 800Hz ODR */
+		{
+			{128, 128, 128},
+			2048,
+		},
+	}
 };
 
 struct mmc35240_data {
@@ -131,6 +171,7 @@ struct mmc35240_data {
 	/* OTP compensation */
 	int axis_coef[3];
 	int axis_scale[3];
+	enum mmc35240_chipset chipset;
 };
 
 static const struct {
@@ -206,6 +247,16 @@ static int mmc35240_hw_set(struct mmc35240_data *data, bool set)
 
 }
 
+static inline bool mmc35240_needs_compensation(enum mmc35240_chipset chipset)
+{
+	switch (chipset) {
+	case MMC35240:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static int mmc35240_init(struct mmc35240_data *data)
 {
 	int ret, y_convert, z_convert;
@@ -220,6 +271,11 @@ static int mmc35240_init(struct mmc35240_data *data)
 
 	dev_dbg(&data->client->dev, "MMC35240 chip id %x\n", reg_id);
 
+	if (reg_id != chip_ids[data->chipset]) {
+		dev_err(&data->client->dev, "Invalid chip %x\n", ret);
+		return -ENODEV;
+	}
+
 	/*
 	 * make sure we restore sensor characteristics, by doing
 	 * a SET/RESET sequence, the axis polarity being naturally
@@ -241,6 +297,9 @@ static int mmc35240_init(struct mmc35240_data *data)
 	if (ret < 0)
 		return ret;
 
+	if (!mmc35240_needs_compensation(data->chipset))
+		return 0;
+
 	ret = regmap_bulk_read(data->regmap, MMC35240_OTP_START_ADDR,
 			       (u8 *)otp_data, sizeof(otp_data));
 	if (ret < 0)
@@ -302,9 +361,51 @@ static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
 				3 * sizeof(__le16));
 }
 
+static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo,
+				  int index, int *val)
+{
+	switch (index) {
+	case AXIS_X:
+		*val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
+		break;
+	case AXIS_Y:
+		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y];
+		break;
+	case AXIS_Z:
+		*val = (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int mmc35240_raw_to_mgauss(int raw[3], int sens[3], int nfo,
+				  int index, int *val)
+{
+	switch (index) {
+	case AXIS_X:
+		*val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
+		break;
+	case AXIS_Y:
+		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] -
+			(raw[AXIS_Z] - nfo)  * 1000 / sens[AXIS_Z];
+		break;
+	case AXIS_Z:
+		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] +
+			(raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 /**
- * mmc35240_raw_to_mgauss - convert raw readings to milli gauss. Also apply
-			    compensation for output value.
+ * memsic_raw_to_mgauss - convert raw readings to milli gauss. Also apply
+			  compensation for output value.
  *
  * @data: device private data
  * @index: axis index for which we want the conversion
@@ -313,40 +414,42 @@ static int mmc35240_read_measurement(struct mmc35240_data *data, __le16 buf[3])
  *
  * Returns: 0 in case of success, -EINVAL when @index is not valid
  */
-static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
-				  __le16 buf[], int *val)
+static int memsic_raw_to_mgauss(struct mmc35240_data *data, int index,
+				__le16 buf[], int *val)
 {
 	int raw[3];
 	int sens[3];
 	int nfo;
+	int ret;
+	int id = data->chipset;
 
 	raw[AXIS_X] = le16_to_cpu(buf[AXIS_X]);
 	raw[AXIS_Y] = le16_to_cpu(buf[AXIS_Y]);
 	raw[AXIS_Z] = le16_to_cpu(buf[AXIS_Z]);
 
-	sens[AXIS_X] = mmc35240_props_table[data->res].sens[AXIS_X];
-	sens[AXIS_Y] = mmc35240_props_table[data->res].sens[AXIS_Y];
-	sens[AXIS_Z] = mmc35240_props_table[data->res].sens[AXIS_Z];
+	sens[AXIS_X] = mmc35240_props_table[id][data->res].sens[AXIS_X];
+	sens[AXIS_Y] = mmc35240_props_table[id][data->res].sens[AXIS_Y];
+	sens[AXIS_Z] = mmc35240_props_table[id][data->res].sens[AXIS_Z];
 
-	nfo = mmc35240_props_table[data->res].nfo;
 
-	switch (index) {
-	case AXIS_X:
-		*val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
-		break;
-	case AXIS_Y:
-		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] -
-			(raw[AXIS_Z] - nfo)  * 1000 / sens[AXIS_Z];
-		break;
-	case AXIS_Z:
-		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y] +
-			(raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
-		break;
+	nfo = mmc35240_props_table[id][data->res].nfo;
+
+	switch (id) {
+	case MMC35240:
+		ret = mmc35240_raw_to_mgauss(raw, sens, nfo, index, val);
+		if (ret < 0)
+			return ret;
+
+		/* apply OTP compensation */
+		*val = (*val) * data->axis_coef[index] /
+			data->axis_scale[index];
+
+		return 0;
+	case MMC34160:
+		return mmc34160_raw_to_mgauss(raw, sens, nfo, index, val);
 	default:
 		return -EINVAL;
 	}
-	/* apply OTP compensation */
-	*val = (*val) * data->axis_coef[index] / data->axis_scale[index];
 
 	return 0;
 }
@@ -367,7 +470,7 @@ static int mmc35240_read_raw(struct iio_dev *indio_dev,
 		mutex_unlock(&data->mutex);
 		if (ret < 0)
 			return ret;
-		ret = mmc35240_raw_to_mgauss(data, chan->address, buf, val);
+		ret = memsic_raw_to_mgauss(data, chan->address, buf, val);
 		if (ret < 0)
 			return ret;
 		return IIO_VAL_INT;
@@ -485,12 +588,27 @@ static const struct regmap_config mmc35240_regmap_config = {
 	.num_reg_defaults = ARRAY_SIZE(mmc35240_reg_defaults),
 };
 
+static const char *mmc35240_match_acpi_device(struct device *dev,
+					      enum mmc35240_chipset *chipset)
+{
+	const struct acpi_device_id *id;
+
+	id = acpi_match_device(dev->driver->acpi_match_table, dev);
+	if (!id)
+		return NULL;
+
+	*chipset = (enum mmc35240_chipset)id->driver_data;
+
+	return dev_name(dev);
+}
+
 static int mmc35240_probe(struct i2c_client *client,
 			  const struct i2c_device_id *id)
 {
 	struct mmc35240_data *data;
 	struct iio_dev *indio_dev;
 	struct regmap *regmap;
+	const char *name;
 	int ret;
 
 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
@@ -509,11 +627,20 @@ static int mmc35240_probe(struct i2c_client *client,
 	data->regmap = regmap;
 	data->res = MMC35240_16_BITS_SLOW;
 
+	if (id) {
+		data->chipset = (enum mmc35240_chipset)(id->driver_data);
+		name = id->name;
+	} else if (ACPI_HANDLE(&client->dev)) {
+		name = mmc35240_match_acpi_device(&client->dev,
+						  &data->chipset);
+	} else
+		return -ENODEV;
+
 	mutex_init(&data->mutex);
 
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->info = &mmc35240_info;
-	indio_dev->name = MMC35240_DRV_NAME;
+	indio_dev->name = name;
 	indio_dev->channels = mmc35240_channels;
 	indio_dev->num_channels = ARRAY_SIZE(mmc35240_channels);
 	indio_dev->modes = INDIO_DIRECT_MODE;
@@ -560,14 +687,16 @@ static const struct dev_pm_ops mmc35240_pm_ops = {
 };
 
 static const struct acpi_device_id mmc35240_acpi_match[] = {
-	{"MMC35240", 0},
+	{"MMC35240", MMC35240},
+	{"MMC34160", MMC34160},
 	{ },
 };
 MODULE_DEVICE_TABLE(acpi, mmc35240_acpi_match);
 
 static const struct i2c_device_id mmc35240_id[] = {
-	{"mmc35240", 0},
-	{}
+	{"mmc35240", MMC35240},
+	{"mmc34160", MMC34160},
+	{ }
 };
 MODULE_DEVICE_TABLE(i2c, mmc35240_id);
 
-- 
1.9.1

Re: [PATCH v2 2/2] iio: magnetometer: add mmc34160 magnetometer driver

[Dan Carpenter]

On Mon, Jul 20, 2015 at 04:52:30PM +0300, Teodora Baluta wrote:
> +static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo,
> +				  int index, int *val)
> +{
> +	switch (index) {
> +	case AXIS_X:
> +		*val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
> +		break;
> +	case AXIS_Y:
> +		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y];
> +		break;
> +	case AXIS_Z:
> +		*val = (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}

We never pass invalid indexes here so this could be replaced with:

static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo,
				  int index, int *val)
{
	*val = (raw[index] - nfo) * 1000 / sens[index];
	return 0;
}

regards,
dan carpenter

Re: [PATCH v2 2/2] iio: magnetometer: add mmc34160 magnetometer driver

[Jonathan Cameron]

On 20/07/15 15:14, Dan Carpenter wrote:
> On Mon, Jul 20, 2015 at 04:52:30PM +0300, Teodora Baluta wrote:
>> +static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo,
>> +				  int index, int *val)
>> +{
>> +	switch (index) {
>> +	case AXIS_X:
>> +		*val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
>> +		break;
>> +	case AXIS_Y:
>> +		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y];
>> +		break;
>> +	case AXIS_Z:
>> +		*val = (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	return 0;
>> +}
> 
> We never pass invalid indexes here so this could be replaced with:
> 
> static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo,
> 				  int index, int *val)
> {
> 	*val = (raw[index] - nfo) * 1000 / sens[index];
> 	return 0;
Even better change the function signature and don't return anything at 
all perhaps?

Anyhow, definitely worth making this change.

> }
> 
> regards,
> dan carpenter
> 

Re: [PATCH v2 2/2] iio: magnetometer: add mmc34160 magnetometer driver

[Dan Carpenter]

On Sun, Aug 02, 2015 at 05:32:30PM +0100, Jonathan Cameron wrote:
> On 20/07/15 15:14, Dan Carpenter wrote:
> > On Mon, Jul 20, 2015 at 04:52:30PM +0300, Teodora Baluta wrote:
> >> +static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo,
> >> +				  int index, int *val)
> >> +{
> >> +	switch (index) {
> >> +	case AXIS_X:
> >> +		*val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
> >> +		break;
> >> +	case AXIS_Y:
> >> +		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y];
> >> +		break;
> >> +	case AXIS_Z:
> >> +		*val = (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
> >> +		break;
> >> +	default:
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> > 
> > We never pass invalid indexes here so this could be replaced with:
> > 
> > static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo,
> > 				  int index, int *val)
> > {
> > 	*val = (raw[index] - nfo) * 1000 / sens[index];
> > 	return 0;
> Even better change the function signature and don't return anything at 
> all perhaps?
> 

Yeah.  Or this:

static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo, int index)
{
	return (raw[index] - nfo) * 1000 / sens[index];
}

regards,
dan carpenter

Re: [PATCH v2 2/2] iio: magnetometer: add mmc34160 magnetometer driver

[Jonathan Cameron]

On 02/08/15 17:37, Dan Carpenter wrote:
> On Sun, Aug 02, 2015 at 05:32:30PM +0100, Jonathan Cameron wrote:
>> On 20/07/15 15:14, Dan Carpenter wrote:
>>> On Mon, Jul 20, 2015 at 04:52:30PM +0300, Teodora Baluta wrote:
>>>> +static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo,
>>>> +				  int index, int *val)
>>>> +{
>>>> +	switch (index) {
>>>> +	case AXIS_X:
>>>> +		*val = (raw[AXIS_X] - nfo) * 1000 / sens[AXIS_X];
>>>> +		break;
>>>> +	case AXIS_Y:
>>>> +		*val = (raw[AXIS_Y] - nfo) * 1000 / sens[AXIS_Y];
>>>> +		break;
>>>> +	case AXIS_Z:
>>>> +		*val = (raw[AXIS_Z] - nfo) * 1000 / sens[AXIS_Z];
>>>> +		break;
>>>> +	default:
>>>> +		return -EINVAL;
>>>> +	}
>>>> +
>>>> +	return 0;
>>>> +}
>>>
>>> We never pass invalid indexes here so this could be replaced with:
>>>
>>> static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo,
>>> 				  int index, int *val)
>>> {
>>> 	*val = (raw[index] - nfo) * 1000 / sens[index];
>>> 	return 0;
>> Even better change the function signature and don't return anything at 
>> all perhaps?
>>
> 
> Yeah.  Or this:
> 
> static int mmc34160_raw_to_mgauss(int raw[3], int sens[3], int nfo, int index)
> {
> 	return (raw[index] - nfo) * 1000 / sens[index];
> }
> 
> regards,
> dan carpenter
*laughs*. Good point ;)
> 
> --
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