On Sat, Sep 3, 2022 at 8:03 AM Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> wrote:
>
> If VREF pin is attached, we should use external VREF source instead of
> the internal. Otherwise we will get wrong measurements on some of the channel
> types.
FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> ---
> changes v5:
> - add "the" before channel
> - refactor error handling on regulator registration
> - use MILLI instead of 1000
> changes v4:
> - use vref_reg pointer instead of bool use_internal_vref
> - move regulator registration to a separate function
> - rework error handling
> - add devm_add_action_or_reset
> ---
> drivers/iio/adc/ti-tsc2046.c | 57 ++++++++++++++++++++++++++++++++++--
> 1 file changed, 55 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/ti-tsc2046.c b/drivers/iio/adc/ti-tsc2046.c
> index 0d9436a69cbfb..c7601b29b3bef 100644
> --- a/drivers/iio/adc/ti-tsc2046.c
> +++ b/drivers/iio/adc/ti-tsc2046.c
> @@ -8,7 +8,9 @@
> #include <linux/bitfield.h>
> #include <linux/delay.h>
> #include <linux/module.h>
> +#include <linux/regulator/consumer.h>
> #include <linux/spi/spi.h>
> +#include <linux/units.h>
>
> #include <asm/unaligned.h>
>
> @@ -175,6 +177,8 @@ struct tsc2046_adc_priv {
> u32 time_per_bit_ns;
>
> struct tsc2046_adc_ch_cfg ch_cfg[TI_TSC2046_MAX_CHAN];
> + unsigned int vref_mv;
> + struct regulator *vref_reg;
I would put pointer first since it will make sizeof(priv) 4 bytes less
on some architectures due to padding elimination.
> };
>
> #define TI_TSC2046_V_CHAN(index, bits, name) \
> @@ -252,7 +256,9 @@ static u8 tsc2046_adc_get_cmd(struct tsc2046_adc_priv *priv, int ch_idx,
> case TI_TSC2046_ADDR_AUX:
> case TI_TSC2046_ADDR_VBAT:
> case TI_TSC2046_ADDR_TEMP0:
> - pd |= TI_TSC2046_SER | TI_TSC2046_PD1_VREF_ON;
> + pd |= TI_TSC2046_SER;
> + if (!priv->vref_reg)
> + pd |= TI_TSC2046_PD1_VREF_ON;
> }
>
> return TI_TSC2046_START | FIELD_PREP(TI_TSC2046_ADDR, ch_idx) | pd;
> @@ -468,7 +474,7 @@ static int tsc2046_adc_read_raw(struct iio_dev *indio_dev,
> * So, it is better to use external voltage-divider driver
> * instead, which is calculating complete chain.
> */
> - *val = TI_TSC2046_INT_VREF;
> + *val = priv->vref_mv;
> *val2 = chan->scan_type.realbits;
> return IIO_VAL_FRACTIONAL_LOG2;
> }
> @@ -740,6 +746,49 @@ static void tsc2046_adc_parse_fwnode(struct tsc2046_adc_priv *priv)
> }
> }
>
> +static void tsc2046_adc_regulator_disable(void *data)
> +{
> + struct tsc2046_adc_priv *priv = data;
> +
> + regulator_disable(priv->vref_reg);
> +}
> +
> +static int tsc2046_adc_configure_regulator(struct tsc2046_adc_priv *priv)
> +{
> + struct device *dev = &priv->spi->dev;
> + int ret;
> +
> + priv->vref_reg = devm_regulator_get_optional(dev, "vref");
> + if (IS_ERR(priv->vref_reg)) {
> + /* If regulator exists but can't be get, return an error */
> + if (PTR_ERR(priv->vref_reg) != -ENODEV)
> + return PTR_ERR(priv->vref_reg);
> + priv->vref_reg = NULL;
> + }
> + if (!priv->vref_reg) {
> + /* Use internal reference */
> + priv->vref_mv = TI_TSC2046_INT_VREF;
> + return 0;
> + }
> +
> + ret = regulator_enable(priv->vref_reg);
> + if (ret)
> + return ret;
> +
> + ret = devm_add_action_or_reset(dev, tsc2046_adc_regulator_disable,
> + priv);
> + if (ret)
> + return ret;
> +
> + ret = regulator_get_voltage(priv->vref_reg);
> + if (ret < 0)
> + return ret;
> +
> + priv->vref_mv = ret / MILLI;
> +
> + return 0;
> +}
> +
> static int tsc2046_adc_probe(struct spi_device *spi)
> {
> const struct tsc2046_adc_dcfg *dcfg;
> @@ -781,6 +830,10 @@ static int tsc2046_adc_probe(struct spi_device *spi)
> indio_dev->num_channels = dcfg->num_channels;
> indio_dev->info = &tsc2046_adc_info;
>
> + ret = tsc2046_adc_configure_regulator(priv);
> + if (ret)
> + return ret;
> +
> tsc2046_adc_parse_fwnode(priv);
>
> ret = tsc2046_adc_setup_spi_msg(priv);
> --
> 2.30.2
>
--
With Best Regards,
Andy Shevchenko
