Re: [PATCH 2/6] iio: adc: ad7173: fix buffers enablement for ad7176-2

Jonathan Cameron
2024-04-06T14:57:00Z

On Mon, 01 Apr 2024 18:32:20 +0300
Dumitru Ceclan via B4 Relay <devnull+dumitru.ceclan.analog.com@kernel.org> wrote:

> From: Dumitru Ceclan <dumitru.ceclan@analog.com>
>
> AD7176-2 does not feature input buffers, enable buffers only on
> supported models.
>
> Fixes: cff259bf7274 ("iio: adc: ad7173: fix buffers enablement for ad7176-2")
> Signed-off-by: Dumitru Ceclan <dumitru.ceclan@analog.com>

How bad is this? If you can find out if writing those bits does anything
harmful (they are reserved and datasheet says should be written 0 I think)
That will help people decide whether to backport the fix?

> ---
> drivers/iio/adc/ad7173.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7173.c b/drivers/iio/adc/ad7173.c
> index f6d29abe1d04..8a95b1391826 100644
> --- a/drivers/iio/adc/ad7173.c
> +++ b/drivers/iio/adc/ad7173.c
> @@ -145,6 +145,7 @@ struct ad7173_device_info {
> unsigned int id;
> char *name;
> bool has_temp;
> + bool has_input_buf;
> bool has_int_ref;
> bool has_ref2;
> u8 num_gpios;
> @@ -212,6 +213,7 @@ static const struct ad7173_device_info ad7173_device_info[] = {
> .num_configs = 4,
> .num_gpios = 2,
> .has_temp = true,
> + .has_input_buf = true,
> .has_int_ref = true,
> .clock = 2 * HZ_PER_MHZ,
> .sinc5_data_rates = ad7173_sinc5_data_rates,
> @@ -224,6 +226,7 @@ static const struct ad7173_device_info ad7173_device_info[] = {
> .num_configs = 8,
> .num_gpios = 4,
> .has_temp = false,
> + .has_input_buf = true,
> .has_ref2 = true,
> .clock = 2 * HZ_PER_MHZ,
> .sinc5_data_rates = ad7173_sinc5_data_rates,
> @@ -237,6 +240,7 @@ static const struct ad7173_device_info ad7173_device_info[] = {
> .num_configs = 8,
> .num_gpios = 4,
> .has_temp = true,
> + .has_input_buf = true,
> .has_int_ref = true,
> .has_ref2 = true,
> .clock = 2 * HZ_PER_MHZ,
> @@ -251,6 +255,7 @@ static const struct ad7173_device_info ad7173_device_info[] = {
> .num_configs = 4,
> .num_gpios = 2,
> .has_temp = true,
> + .has_input_buf = true,
> .has_int_ref = true,
> .clock = 16 * HZ_PER_MHZ,
> .sinc5_data_rates = ad7175_sinc5_data_rates,
> @@ -263,6 +268,7 @@ static const struct ad7173_device_info ad7173_device_info[] = {
> .num_configs = 8,
> .num_gpios = 4,
> .has_temp = true,
> + .has_input_buf = true,
> .has_int_ref = true,
> .has_ref2 = true,
> .clock = 16 * HZ_PER_MHZ,
> @@ -289,6 +295,7 @@ static const struct ad7173_device_info ad7173_device_info[] = {
> .num_configs = 4,
> .num_gpios = 2,
> .has_temp = true,
> + .has_input_buf = true,
> .has_int_ref = true,
> .clock = 16 * HZ_PER_MHZ,
> .odr_start_value = AD7177_ODR_START_VALUE,
> @@ -932,7 +939,7 @@ static int ad7173_fw_parse_channel_config(struct iio_dev *indio_dev)
> AD7173_CH_ADDRESS(chan_arr[chan_index].channel,
> chan_arr[chan_index].channel2);
> chan_st_priv->cfg.bipolar = false;
> - chan_st_priv->cfg.input_buf = true;
> + chan_st_priv->cfg.input_buf = st->info->has_input_buf;
> chan_st_priv->cfg.ref_sel = AD7173_SETUP_REF_SEL_INT_REF;
> st->adc_mode |= AD7173_ADC_MODE_REF_EN;
>
> @@ -989,7 +996,7 @@ static int ad7173_fw_parse_channel_config(struct iio_dev *indio_dev)
>
> chan_st_priv->ain = AD7173_CH_ADDRESS(ain[0], ain[1]);
> chan_st_priv->chan_reg = chan_index;
> - chan_st_priv->cfg.input_buf = true;
> + chan_st_priv->cfg.input_buf = st->info->has_input_buf;
> chan_st_priv->cfg.odr = 0;
>
> chan_st_priv->cfg.bipolar = fwnode_property_read_bool(child, "bipolar");
>