Re: [PATCH v3 2/2] iio: magnetometer: add mmc34160 magnetometer driver

[Teodora Baluta <teodora.baluta@intel.com>]

On Sat, Aug 15, 2015 at 09:54:28PM +0100, Jonathan Cameron wrote:
> On 15/08/15 21:47, Jonathan Cameron wrote:
> > On 02/08/15 17:43, Jonathan Cameron wrote:
> >> On 02/08/15 17:40, Jonathan Cameron wrote:
> >>> On 31/07/15 15:27, Teodora Baluta wrote:
> >>>> 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>
> >>> Couple of comments inline.
> >>>
> >>> Applied to the togreg branch of iio.git - initially pushed out as testing
> >>> for the autobuilders to play with it.
> >>>
> >> oops, didn't check it had actually applied cleanly.  Right now it doesn't.
> >> Perhaps connected to various fixes working there way through.  I'll hold
> >> this patch back for now on the basis it'll probably work itself out
> >> as they hit the togreg branch (hopefully later this week).
> >>
> >> Jonathan
> > 
> > Applied to the togreg branch of iio.git (with some fuzz).
> Spoke too soon.  The result doesn't build (id undefined at line 414).  Could
> you rebase and send me an updated version against my testing branch?

Sure, will send a single v4 patch rebased against the testing branch.
There's a comment inline.

Thanks for the review & patience,
Teodora

> 
> Thanks,
> 
> Jonathan
> > 
> > Thanks,
> > 
> > Jonathan
> >>> Thanks,
> >>>
> >>> Jonathan
> >>>> ---
> >>>>  drivers/iio/magnetometer/Kconfig    |   5 +-
> >>>>  drivers/iio/magnetometer/mmc35240.c | 203 ++++++++++++++++++++++++++++--------
> >>>>  2 files changed, 161 insertions(+), 47 deletions(-)
> >>>>
> >>>> diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
> >>>> index dcadfc4..baf59d9 100644
> >>>> --- a/drivers/iio/magnetometer/Kconfig
> >>>> +++ b/drivers/iio/magnetometer/Kconfig
> >>>> @@ -52,8 +52,9 @@ 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 3-axis magnetic
> >>>> +	  sensor. This driver also adds support for the MEMSIC MMC34160 3-axis magnetic
> >>>> +	  sensor.
> >>> Sometimes I wonder if we should have a standard form for multi device supporting
> >>> driver Kconfig help text.  This one seems rather unwieldy!  Anyhow we don't
> >>> so until we do it can be like this.

Actually, the second version had this somehow fixed (by using 'and'
instead of a new sentence thus shortening the Kconfig description) as
per your suggestion. It slipped out of version 3.

> >>>>  
> >>>>  	  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 a4259bf..7a5921b 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 */
> >>>> -	{
> >>>> -		{1024, 1024, 1024},
> >>>> -		32768,
> >>>> -	},
> >>>> -	/* 16 bits, 250Hz ODR */
> >>>> -	{
> >>>> -		{1024, 1024, 770},
> >>>> -		32768,
> >>>> -	},
> >>>> -	/* 14 bits, 450Hz ODR */
> >>>> +} mmc35240_props_table[MMC_MAX_CHIPS][4] = {
> >>>> +	/* MMC35240 */
> >>>>  	{
> >>>> -		{256, 256, 193},
> >>>> -		8192,
> >>>> +		/* 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,
> >>>> +		},
> >>>>  	},
> >>>> -	/* 12 bits, 800Hz ODR */
> >>>> +	/* MMC34160 */
> >>>>  	{
> >>>> -		{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)
> >>>>  				  coil_bit);
> >>>>  }
> >>>>  
> >>>> +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 +271,10 @@ 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 RESET/SET sequence
> >>>> @@ -240,6 +295,9 @@ 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)
> >>>> @@ -301,9 +359,38 @@ 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)
> >>>> +{
> >>>> +	*val = (raw[index] - nfo) * 1000 / sens[index];
> >>>> +	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
> >>>> @@ -312,8 +399,8 @@ 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,
> >>> Awkward.  Normally I'd argue in favour of keeping the original prefix
> >>> (in keeping with the driver name) but here you have reused that name
> >>> as was obviously appropriate.  Ah well I guess memsic_ will have
> >>> to do as a prefix!
> >>>> +				__le16 buf[], int *val)
> >>>>  {
> >>>>  	int raw[3];
> >>>>  	int sens[3];
> >>>> @@ -323,29 +410,29 @@ static int mmc35240_raw_to_mgauss(struct mmc35240_data *data, int index,
> >>>>  	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;
> >>>>  }
> >>>> @@ -366,7 +453,7 @@ 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;
> >>>> @@ -484,12 +571,27 @@ 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));
> >>>> @@ -507,11 +609,20 @@ 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;
> >>>> @@ -564,14 +675,16 @@ static const struct of_device_id mmc35240_of_match[] = {
> >>>>  MODULE_DEVICE_TABLE(of, mmc35240_of_match);
> >>>>  
> >>>>  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);
> >>>>  
> >>>>
> >>>
> >>> --
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> >>
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> > 
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