Re: [PATCH] iio: adc: rockchip_saradc: Add support for RV1106

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 10 Aug 2026 12:08:26 +0300
Vladislav Leonov <vlad@zlab.su> wrote:

> The Successive Approximation ADC (SARADC) in RV1106 uses the v2
> controller and supports:
> - 10-bit resolution
> - Up to 1MS/s sampling rate
> - 2 single-ended input channels
> 
> "dt-bindings: iio: adc: rockchip-saradc: Add RV1106 compatible"
> documents "rockchip,rv1106-saradc" as falling back to
> "rockchip,rk3588-saradc" (see Link below). The two IP blocks are not
> equivalent, though: per the RV1106 TRM v0.3, chapter 20 (SAR-ADC),
> RV1106 only has 2 channels at 10-bit resolution, versus 8 channels
> at 12-bit on RK3588. Without a dedicated match entry, the driver
> binds via the fallback compatible and uses the RK3588 channel table,
> which reports 8 channels instead of 2, and an in_voltage_scale that
> is off by exactly 4x (4096 vs 1024 full-scale).
> 
> Add a dedicated compatible/data pair for RV1106 with the correct
> 2-channel, 10-bit layout.
> 
> Tested on a custom RV1106-based board, with:
> 
>   &saradc {
> 	vref-supply = <&vcc_saradc>; /* 1.8V fixed regulator */
> 	status = "okay";
>   };
> 
> Before this patch:
>   # ls /sys/bus/iio/devices/iio:device0/in_voltage*_raw | wc -l
>   8
>   # cat /sys/bus/iio/devices/iio:device0/in_voltage_scale
>   0.439453125
> 
> After this patch:
>   # ls /sys/bus/iio/devices/iio:device0/in_voltage*_raw | wc -l
>   2
>   # cat /sys/bus/iio/devices/iio:device0/in_voltage_scale
>   1.757812500
> 
> Link: https://lore.kernel.org/all/20260714131631.v2.1.0b846080833e4b836793c43fc26d1c6d817cf9b4@changeid/
> Signed-off-by: Vladislav Leonov <vlad@zlab.su>

Hi Vladislav,

Could you also send a fix for the dt-binding as it clearly
shouldn't claim the fallback compatible!

Whilst I can see why you did here, in general don't reply
to an existing series when sending a new one.  Your link tag
is sufficient to associate the two.

I'll give this a little longer on list to let other comment, but
looks good to me.

Thanks,

Jonathan

> ---
>  drivers/iio/adc/rockchip_saradc.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c
> index 0f0bf2906af0..5c45fae11890 100644
> --- a/drivers/iio/adc/rockchip_saradc.c
> +++ b/drivers/iio/adc/rockchip_saradc.c
> @@ -348,6 +348,19 @@ static const struct rockchip_saradc_data rk3588_saradc_data = {
>  	.read = rockchip_saradc_read_v2,
>  };
>  
> +static const struct iio_chan_spec rockchip_rv1106_saradc_iio_channels[] = {
> +	SARADC_CHANNEL(0, "adc0", 10),
> +	SARADC_CHANNEL(1, "adc1", 10),
> +};
> +
> +static const struct rockchip_saradc_data rv1106_saradc_data = {
> +	.channels = rockchip_rv1106_saradc_iio_channels,
> +	.num_channels = ARRAY_SIZE(rockchip_rv1106_saradc_iio_channels),
> +	.clk_rate = 1000000,
> +	.start = rockchip_saradc_start_v2,
> +	.read = rockchip_saradc_read_v2,
> +};
> +
>  static const struct of_device_id rockchip_saradc_match[] = {
>  	{
>  		.compatible = "rockchip,saradc",
> @@ -370,6 +383,9 @@ static const struct of_device_id rockchip_saradc_match[] = {
>  	}, {
>  		.compatible = "rockchip,rk3588-saradc",
>  		.data = &rk3588_saradc_data,
> +	}, {
> +		.compatible = "rockchip,rv1106-saradc",
> +		.data = &rv1106_saradc_data,
>  	},
>  	{ }
>  };