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Message-ID: <038ea3e7-53d5-4e49-ad35-cc2a58e4d808@tuxon.dev>
Date: Sun, 14 Sep 2025 18:43:55 +0300
From: Claudiu Beznea <claudiu.beznea@...on.dev>
To: Varshini Rajendran <varshini.rajendran@...rochip.com>,
eugen.hristev@...aro.org, jic23@...nel.org, dlechner@...libre.com,
nuno.sa@...log.com, andy@...nel.org, robh@...nel.org, krzk+dt@...nel.org,
conor+dt@...nel.org, nicolas.ferre@...rochip.com,
alexandre.belloni@...tlin.com, srini@...nel.org, linux-iio@...r.kernel.org,
devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 04/15] iio: adc: at91-sama5d2_adc: update calibration
index, validation condition
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@...rochip.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;
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