Re: [PATCH V4] iio: adc: ad7124: Add direct reg access

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 11 Feb 2020 10:44:53 +0200
Mircea Caprioru <mircea.caprioru@analog.com> wrote:

> This patch adds the posibility do read and write registers from userspace
> using the kernel debug direct register access option.
> 
> Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Applied to the togreg branch of iio.git and pushed out as testing for
the autobuilders to play with it.

Thanks,

Jonathan

> ---
> Changelog V4:
> - verify limit againg ARRAY_SIZE(ad7124_reg_size)
> 
>  drivers/iio/adc/ad7124.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
> index f0206d819fda..a3c0647a5391 100644
> --- a/drivers/iio/adc/ad7124.c
> +++ b/drivers/iio/adc/ad7124.c
> @@ -98,6 +98,14 @@ static const unsigned int ad7124_gain[8] = {
>  	1, 2, 4, 8, 16, 32, 64, 128
>  };
>  
> +static const unsigned int ad7124_reg_size[] = {
> +	1, 2, 3, 3, 2, 1, 3, 3, 1, 2, 2, 2, 2,
> +	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
> +	2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3,
> +	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
> +	3, 3, 3, 3, 3
> +};
> +
>  static const int ad7124_master_clk_freq_hz[3] = {
>  	[AD7124_LOW_POWER] = 76800,
>  	[AD7124_MID_POWER] = 153600,
> @@ -427,6 +435,27 @@ static int ad7124_write_raw(struct iio_dev *indio_dev,
>  	}
>  }
>  
> +static int ad7124_reg_access(struct iio_dev *indio_dev,
> +			     unsigned int reg,
> +			     unsigned int writeval,
> +			     unsigned int *readval)
> +{
> +	struct ad7124_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	if (reg >= ARRAY_SIZE(ad7124_reg_size))
> +		return -EINVAL;
> +
> +	if (readval)
> +		ret = ad_sd_read_reg(&st->sd, reg, ad7124_reg_size[reg],
> +				     readval);
> +	else
> +		ret = ad_sd_write_reg(&st->sd, reg, ad7124_reg_size[reg],
> +				      writeval);
> +
> +	return ret;
> +}
> +
>  static IIO_CONST_ATTR(in_voltage_scale_available,
>  	"0.000001164 0.000002328 0.000004656 0.000009313 0.000018626 0.000037252 0.000074505 0.000149011 0.000298023");
>  
> @@ -442,6 +471,7 @@ static const struct attribute_group ad7124_attrs_group = {
>  static const struct iio_info ad7124_info = {
>  	.read_raw = ad7124_read_raw,
>  	.write_raw = ad7124_write_raw,
> +	.debugfs_reg_access = &ad7124_reg_access,
>  	.validate_trigger = ad_sd_validate_trigger,
>  	.attrs = &ad7124_attrs_group,
>  };