From: Andy Shevchenko <andy@kernel.org>
To: Haibo Chen <haibo.chen@nxp.com>
Cc: "Jonathan Cameron" <jic23@kernel.org>,
"David Lechner" <dlechner@baylibre.com>,
"Nuno Sá" <nuno.sa@analog.com>, "Shawn Guo" <shawnguo@kernel.org>,
"Sascha Hauer" <s.hauer@pengutronix.de>,
"Pengutronix Kernel Team" <kernel@pengutronix.de>,
"Fabio Estevam" <festevam@gmail.com>,
linux-iio@vger.kernel.org, imx@lists.linux.dev,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iio: adc: imx93_adc: load calibrated values even calibration failed
Date: Wed, 23 Apr 2025 19:43:40 +0300 [thread overview]
Message-ID: <aAkYvE6VtoQItM5o@smile.fi.intel.com> (raw)
In-Reply-To: <20250423-adcpatch-v1-1-b0e84c27ae98@nxp.com>
On Wed, Apr 23, 2025 at 04:02:48PM +0800, Haibo Chen wrote:
> ADC calibration might fail because of the noise on reference voltage.
> To avoid calibration fail, need to meet the following requirement:
> ADC reference voltage Noise < 1.8V * 1/2^ENOB
>
> For the case which the ADC reference voltage on board do not meet
> the requirement, still load the calibrated values, so ADC can also
> work but maybe not that accurate.
...
> #define IMX93_ADC_PCDR6 0x118
> #define IMX93_ADC_PCDR7 0x11c
> #define IMX93_ADC_CALSTAT 0x39C
> +#define IMX93_ADC_CALCFG0 0X3A0
Please, keep one style of the hex values.
If the small letters are less used, prepare a patch to convert them, otherwise
do that for capital letters.
...
> + if (msr & IMX93_ADC_MSR_CALFAIL_MASK)
Please keep {} as the body is quite long and it's easy to make a mistake in a
long term.
> + /*
> + * Only give warning here, this means the noise of the
> + * reference voltage do not meet the requirement:
> + * ADC reference voltage Noise < 1.8V * 1/2^ENOB
> + * And the reault of ADC is not that accurate.
> + */
> dev_warn(adc->dev, "ADC calibration failed!\n");
> - imx93_adc_power_down(adc);
> - return -EAGAIN;
> - }
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2025-04-23 17:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-23 8:02 [PATCH] iio: adc: imx93_adc: load calibrated values even calibration failed Haibo Chen
2025-04-23 16:43 ` Andy Shevchenko [this message]
2025-06-17 3:07 ` Bough Chen
2025-06-21 15:58 ` Jonathan Cameron
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