Re: [PATCH 04/15] iio: adc: at91-sama5d2_adc: update calibration index, validation condition

[Claudiu Beznea <claudiu.beznea@tuxon.dev>]

Hi, Varshini,

On 8/4/25 13:02, Varshini Rajendran wrote:
> Add additional condition for validating the calibration data read from
> the OTP through nvmem device interface. Adjust the calibration indexes
> of sama7g5 according to the buffer received from the OTP memory.
> 
> Signed-off-by: Varshini Rajendran <varshini.rajendran@microchip.com>
> ---
>  drivers/iio/adc/at91-sama5d2_adc.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
> index c3450246730e..d952109a64a9 100644
> --- a/drivers/iio/adc/at91-sama5d2_adc.c
> +++ b/drivers/iio/adc/at91-sama5d2_adc.c
> @@ -445,6 +445,14 @@ static const struct at91_adc_reg_layout sama7g5_layout = {
>  #define at91_adc_writel(st, reg, val)					\
>  	writel_relaxed(val, (st)->base + (st)->soc_info.platform->layout->reg)
>  
> +/*
> + * The calibration data has a TAG to recognize the packet
> + * The tag has a constant value "ACST" with the ASCII
> + * equivalent 0x41435354. This is used to validate the
> + * calibration data obtained from the OTP.
> + */
> +#define AT91_TEMP_CALIB_TAG	0x41435354
> +
>  /**
>   * struct at91_adc_platform - at91-sama5d2 platform information struct
>   * @layout:		pointer to the reg layout struct
> @@ -504,10 +512,10 @@ struct at91_adc_temp_sensor_clb {
>   * @AT91_ADC_TS_CLB_IDX_MAX: max index for temperature calibration packet in OTP
>   */
>  enum at91_adc_ts_clb_idx {
> -	AT91_ADC_TS_CLB_IDX_P1 = 2,
> -	AT91_ADC_TS_CLB_IDX_P4 = 5,
> -	AT91_ADC_TS_CLB_IDX_P6 = 7,
> -	AT91_ADC_TS_CLB_IDX_MAX = 19,
> +	AT91_ADC_TS_CLB_IDX_P1 = 1,
> +	AT91_ADC_TS_CLB_IDX_P4 = 4,
> +	AT91_ADC_TS_CLB_IDX_P6 = 6,
> +	AT91_ADC_TS_CLB_IDX_MAX = 18,
>  };
>  
>  /* Temperature sensor calibration - Vtemp voltage sensitivity to temperature. */
> @@ -2281,7 +2289,7 @@ static int at91_adc_temp_sensor_init(struct at91_adc_state *st,
>  		dev_err(dev, "Failed to read calibration data!\n");
>  		return PTR_ERR(buf);
>  	}
> -	if (len < AT91_ADC_TS_CLB_IDX_MAX * 4) {
> +	if (len < AT91_ADC_TS_CLB_IDX_MAX * 4  || buf[0] != AT91_TEMP_CALIB_TAG) {

Can buf[0] != AT91_TEMP_CALIB_TAG with the new code?


>  		dev_err(dev, "Invalid calibration data!\n");
>  		ret = -EINVAL;
>  		goto free_buf;