Re: [PATCH v3 1/6] iio: adc: ad4080: fix chip identification

Nuno Sá
2025-10-07T14:40:33Z

On Tue, 2025-10-07 at 11:15 +0000, Antoniu Miclaus wrote:
> Fix AD4080 chip identification by using the correct 16-bit product ID
> (0x0050) instead of GENMASK(2, 0). Update the chip reading logic to
> use regmap_bulk_read to read both PRODUCT_ID_L and PRODUCT_ID_H
> registers and combine them into a 16-bit value.
>
> The original implementation was incorrectly reading only 3 bits,
> which would not correctly identify the AD4080 chip.
>
> Fixes: 6b31ba1811b6 ("iio: adc: ad4080: add driver support")
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---

Small nitpick below that Jonathan might tweak if he thinks it's worth it.
Anyways,

Reviewed-by: Nuno Sá <nuno.sa@analog.com>

> changes in v3:
>  - use le16_to_cpu to convert the read little-endian value to CPU endianness
>  drivers/iio/adc/ad4080.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/adc/ad4080.c b/drivers/iio/adc/ad4080.c
> index 6e61787ed321..ae5a975a47a5 100644
> --- a/drivers/iio/adc/ad4080.c
> +++ b/drivers/iio/adc/ad4080.c
> @@ -125,7 +125,7 @@
>
>  /* Miscellaneous Definitions */
>  #define
> AD4080_SPI_READ BIT(7)
> -#define AD4080_CHIP_ID GENMASK(2, 0)
> +#define AD4080_CHIP_ID 0x0050
>
>  #define AD4080_LVDS_CNV_CLK_CNT_MAX 7
>
> @@ -445,7 +445,8 @@ static int ad4080_setup(struct iio_dev *indio_dev)
>  {
>   struct ad4080_state *st = iio_priv(indio_dev);
>   struct device *dev = regmap_get_device(st->regmap);
> - unsigned int id;
> + __le16 id_le;
> + u16 id;
>   int ret;
>
>   ret = regmap_write(st->regmap, AD4080_REG_INTERFACE_CONFIG_A,
> @@ -458,10 +459,11 @@ static int ad4080_setup(struct iio_dev *indio_dev)
>   if (ret)
>   return ret;
>
> - ret = regmap_read(st->regmap, AD4080_REG_CHIP_TYPE, &id);
> + ret = regmap_bulk_read(st->regmap, AD4080_REG_PRODUCT_ID_L, &id_le,
> 2);

sizeof(id_le)

>   if (ret)
>   return ret;
>
> + id = le16_to_cpu(id_le);
>   if (id != AD4080_CHIP_ID)
>   dev_info(dev, "Unrecognized CHIP_ID 0x%X\n", id);
>