Re: [PATCH 4/4] iio: magnetometer: ak8974: debug AMI306 calibration data

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 17 Aug 2017 15:56:12 +0200
Michał Mirosław <mirq-linux@rere.qmqm.pl> wrote:

> Use AMI306 calibration data for randomness and debugging.
> 
> Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Applied to the togreg branch of iio.git and pushed out as testing for the
autobuilders to play with it.

Thanks,

Jonathan
> ---
>  drivers/iio/magnetometer/ak8974.c | 41 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
> 
> diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c
> index d8c45206ba00..b3221b34606b 100644
> --- a/drivers/iio/magnetometer/ak8974.c
> +++ b/drivers/iio/magnetometer/ak8974.c
> @@ -445,6 +445,20 @@ static int ak8974_selftest(struct ak8974 *ak8974)
>  	return 0;
>  }
>  
> +static void ak8974_read_calib_data(struct ak8974 *ak8974, unsigned int reg,
> +				   __le16 *tab, size_t tab_size)
> +{
> +	int ret = regmap_bulk_read(ak8974->map, reg, tab, tab_size);
> +	if (ret) {
> +		memset(tab, 0xFF, tab_size);
> +		dev_warn(&ak8974->i2c->dev,
> +			 "can't read calibration data (regs %u..%u): %d\n",
> +			 reg, reg + tab_size - 1, ret);
> +	} else {
> +		add_device_randomness(tab, tab_size);
> +	}
> +}
> +
>  static int ak8974_detect(struct ak8974 *ak8974)
>  {
>  	unsigned int whoami;
> @@ -490,6 +504,33 @@ static int ak8974_detect(struct ak8974 *ak8974)
>  	ak8974->name = name;
>  	ak8974->variant = whoami;
>  
> +	if (whoami == AK8974_WHOAMI_VALUE_AMI306) {
> +		__le16 fab_data1[9], fab_data2[3];
> +		int i;
> +
> +		ak8974_read_calib_data(ak8974, AMI306_FINEOUTPUT_X,
> +				       fab_data1, sizeof(fab_data1));
> +		ak8974_read_calib_data(ak8974, AMI306_OFFZERO_X,
> +				       fab_data2, sizeof(fab_data2));
> +
> +		for (i = 0; i < 3; ++i) {
> +			static const char axis[3] = "XYZ";
> +			static const char pgaxis[6] = "ZYZXYX";
> +			unsigned offz = le16_to_cpu(fab_data2[i]) & 0x7F;
> +			unsigned fine = le16_to_cpu(fab_data1[i]);
> +			unsigned sens = le16_to_cpu(fab_data1[i + 3]);
> +			unsigned pgain1 = le16_to_cpu(fab_data1[i + 6]);
> +			unsigned pgain2 = pgain1 >> 8;
> +
> +			pgain1 &= 0xFF;
> +
> +			dev_info(&ak8974->i2c->dev,
> +				 "factory calibration for axis %c: offz=%u sens=%u fine=%u pga%c=%u pga%c=%u\n",
> +				 axis[i], offz, sens, fine, pgaxis[i * 2],
> +				 pgain1, pgaxis[i * 2 + 1], pgain2);
> +		}
> +	}
> +
>  	return 0;
>  }
>