[PATCH v2] adc: rockchip-saradc: add support for getting reference voltage value

[Kever Yang]

Hi Peter,

Peter Cai <peter at typeblog.net> 于2022年2月5日周六 21:49写道：
>
> Mirroring commit 97ab802aa36f ("adc: meson-saradc: add support for
> getting reference voltage value") for meson-saradc, this adds support
> for getting the "vref-supply" regulator and register it as the ADC's
> reference voltage regulator, so clients can translate sampled ADC values
> to voltage.
>
> Signed-off-by: Peter Cai <peter at typeblog.net>
> Reviewed-by: John Keeping <john at metanate.com>
> Tested-by: John Keeping <john at metanate.com>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Philipp Tomsich <philipp.tomsich at vrull.eu>
> Cc: Kever Yang <kever.yang at rock-chips.com>

Reviewed-by: Kever Yang <kever.yang at rock-chips.com>

Thanks,
- Kever
> ---
> Changes in v2:
> - Reordered local variables in `rockchip_saradc_probe`.
> ---
>  drivers/adc/rockchip-saradc.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
>
> diff --git a/drivers/adc/rockchip-saradc.c b/drivers/adc/rockchip-saradc.c
> index e464d33f2267..4007188133c8 100644
> --- a/drivers/adc/rockchip-saradc.c
> +++ b/drivers/adc/rockchip-saradc.c
> @@ -13,6 +13,7 @@
>  #include <asm/io.h>
>  #include <linux/bitops.h>
>  #include <linux/err.h>
> +#include <power/regulator.h>
>
>  #define SARADC_CTRL_CHN_MASK           GENMASK(2, 0)
>  #define SARADC_CTRL_POWER_CTRL         BIT(3)
> @@ -100,8 +101,11 @@ int rockchip_saradc_stop(struct udevice *dev)
>
>  int rockchip_saradc_probe(struct udevice *dev)
>  {
> +       struct adc_uclass_plat *uc_pdata = dev_get_uclass_plat(dev);
>         struct rockchip_saradc_priv *priv = dev_get_priv(dev);
> +       struct udevice *vref;
>         struct clk clk;
> +       int vref_uv;
>         int ret;
>
>         ret = clk_get_by_index(dev, 0, &clk);
> @@ -114,6 +118,23 @@ int rockchip_saradc_probe(struct udevice *dev)
>
>         priv->active_channel = -1;
>
> +       ret = device_get_supply_regulator(dev, "vref-supply", &vref);
> +       if (ret) {
> +               printf("can't get vref-supply: %d\n", ret);
> +               return ret;
> +       }
> +
> +       vref_uv = regulator_get_value(vref);
> +       if (vref_uv < 0) {
> +               printf("can't get vref-supply value: %d\n", vref_uv);
> +               return vref_uv;
> +       }
> +
> +       /* VDD supplied by common vref pin */
> +       uc_pdata->vdd_supply = vref;
> +       uc_pdata->vdd_microvolts = vref_uv;
> +       uc_pdata->vss_microvolts = 0;
> +
>         return 0;
>  }
>
> --
> 2.35.1
>