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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?MSjlhvr3Kg/7kKs3AtHdWcI0HCtjeD/Op9pxkI9QDNYbbwcOw99kK6HqS17K?= =?us-ascii?Q?0pRHuwnQqQGDgvzWO8IaXaxYthScEMTEDPVEBgE+uOI5dlNYePwtnmClas19?= =?us-ascii?Q?9+zvg2ognE/s6AUcC8ftjjDBDK/ZQ1GpG0qxrzer8lOlPI/NfO+5oc3wVTA/?= =?us-ascii?Q?JWhsN1h5ykwbpMfS2wP8PNt0X9qr6mn7j6tAC/v+1q8zrbphJaaClS4H5F3y?= =?us-ascii?Q?oZg/oPiBMIyQnMrPWsFumWlI2dFrkBOK+4hhD9Z/38obRrJGIz9+mAHWFGNa?= =?us-ascii?Q?gFsPVVmDAzMeHIJdQTkU8qeSRvIX7lIMBD0hlzTk60X/7IYy6RVDG4Z5Coj5?= =?us-ascii?Q?Gira2WETJslAXq64+AdH5yU8gRm+en0kTXiqdgUdmB9GbfrWPSm+3+0M0uxa?= =?us-ascii?Q?kSeSCZO5GwuvL3S3RhNsTxdAhmeP2IgvLevgHpIis3Xur0T9W8WZvfeCuwXW?= =?us-ascii?Q?nfdAtLH0aBEuRA5dfmtvfsONYcDfp0yBrYUr4ajzYrEax2K+inhUIHmwNb9B?= =?us-ascii?Q?cngfE2tWWNMkwlFyVDBz3rLLnCvDYwAAGs7YcLsBYLjVrEGDliyafIF5b+mP?= =?us-ascii?Q?8IujIJsgihqFeNJlvdW4/QK4rrfj6P/717Ycyhj26ckbQelaP7tEBoX4N9ZJ?= =?us-ascii?Q?2am3WRVDCyxwvfS84PVJxpYu0n0gC5uyFs8mFCE8c7RCWn7ZqmcLbsQ1CiMw?= =?us-ascii?Q?DTHEsYTvycdOmGD0TdS3Jb8hgnShjOePzxwlA/Ij8tIg17SIv5nWjkKHMg92?= =?us-ascii?Q?KGG4N4RSBRw1l6GBdT+wZFalZ9CThOrG/e3zBQu6GCssV72KTs/gcun4LPzQ?= =?us-ascii?Q?+kFXazp3r+KEHalxIQeEo9wJ5aR9eXBr88xmNig3TGjMmUFoGJdIyoTdEkKG?= =?us-ascii?Q?rHmcKIlPFyQCxbZBIgQIXKxTBFMdpiMlrRPrK4LFMpuDGLgffWb0ee3YINDy?= =?us-ascii?Q?OvrINwKp2XoJEAUw9mox/jP83mhJ8k9s8FNI5uMT3M6Zadexd1J60FWxl9wD?= =?us-ascii?Q?JieVYGOXbPcz49/SlzTkVcKtlcrstVDpHemkbGSaJoJ5BSdagv+9IejSedAo?= =?us-ascii?Q?frAELr9BBhU+LtOQTBgBnkkQFC5y98q6CXq+cE6h1qgyG8MT3OWaavesKu1R?= =?us-ascii?Q?3I0ZOeUzdCce67bklDmgsedLx2kH2Zmg9IapR/irCvSrupP2YZcAjpTCBP4o?= =?us-ascii?Q?izy2VllJTuIFm6mTuPWskg1/K6prgPwNs8fNz27XFHwf4gFciT97MLTr/cDQ?= =?us-ascii?Q?qYRStwF8AqWUrx+C+wdNNLe2+kXPK3KIkcqdOavvcSHBbb0kTwQ0yoJrYyFg?= =?us-ascii?Q?t73Bx8MyYhK8S9MO1ceyj2qY1AG2xDgn8hxxWX9BOZKrOcA9HMz/rOrkcylL?= =?us-ascii?Q?b4LjJeT30LaZcz3YKpug/VJnOrRPYbgOmesIEDbKEStdneLLf12tW7ssknAv?= =?us-ascii?Q?9e8l6nLaYlKBKsjcoLvF8E9X00iDhjbqwQ5bPq7uihXzPi3Mb11B+oyC8m5+?= =?us-ascii?Q?MO6yFaeAgVVpHQRekY69y6gbIfSHzF9UFZXK/UUda4rfejWEXpl0YrkcH6e6?= =?us-ascii?Q?gnFXuyzQG6TCdVD9PTSl+m8bJOlMkAOxaglimni1?= X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: 247861e7-7299-409d-5a66-08ddd9bba648 X-MS-Exchange-CrossTenant-AuthSource: PAXPR04MB9642.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Aug 2025 16:16:53.0105 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: H7LZ7XsossFAVt8jR9Bb1xXNQmsp1PaTIIJMcDfiWncfmQzzLq1mX1JlY2Z73K2QFvd+ZDKPTiGglr+ISGXejA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DU2PR04MB9051 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250812_091701_153868_FED4A5F5 X-CRM114-Status: GOOD ( 25.70 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Aug 12, 2025 at 04:04:23PM +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. > > Signed-off-by: Haibo Chen Reviewed-by: Frank Li > --- > drivers/iio/adc/imx93_adc.c | 18 +++++++++++++++--- > 1 file changed, 15 insertions(+), 3 deletions(-) > > diff --git a/drivers/iio/adc/imx93_adc.c b/drivers/iio/adc/imx93_adc.c > index 8471737ac04a2bac0417a6397f20865f6a2c01ca..17b0a2548b0a3614ac537b01e28bc3144d17d6fc 100644 > --- a/drivers/iio/adc/imx93_adc.c > +++ b/drivers/iio/adc/imx93_adc.c > @@ -38,6 +38,7 @@ > #define IMX93_ADC_PCDR6 0x118 > #define IMX93_ADC_PCDR7 0x11C > #define IMX93_ADC_CALSTAT 0x39C > +#define IMX93_ADC_CALCFG0 0x3A0 > > /* ADC bit shift */ > #define IMX93_ADC_MCR_MODE_MASK BIT(29) > @@ -58,6 +59,8 @@ > #define IMX93_ADC_IMR_ECH_MASK BIT(0) > #define IMX93_ADC_PCDR_CDATA_MASK GENMASK(11, 0) > > +#define IMX93_ADC_CALCFG0_LDFAIL_MASK BIT(4) > + > /* ADC status */ > #define IMX93_ADC_MSR_ADCSTATUS_IDLE 0 > #define IMX93_ADC_MSR_ADCSTATUS_POWER_DOWN 1 > @@ -145,7 +148,7 @@ static void imx93_adc_config_ad_clk(struct imx93_adc *adc) > > static int imx93_adc_calibration(struct imx93_adc *adc) > { > - u32 mcr, msr; > + u32 mcr, msr, calcfg; > int ret; > > /* make sure ADC in power down mode */ > @@ -158,6 +161,11 @@ static int imx93_adc_calibration(struct imx93_adc *adc) > > imx93_adc_power_up(adc); > > + /* Enable loading of calibrated values even in fail condition */ > + calcfg = readl(adc->regs + IMX93_ADC_CALCFG0); > + calcfg |= IMX93_ADC_CALCFG0_LDFAIL_MASK; > + writel(calcfg, adc->regs + IMX93_ADC_CALCFG0); > + > /* > * TODO: we use the default TSAMP/NRSMPL/AVGEN in MCR, > * can add the setting of these bit if need in future. > @@ -180,9 +188,13 @@ static int imx93_adc_calibration(struct imx93_adc *adc) > /* check whether calbration is success or not */ > msr = readl(adc->regs + IMX93_ADC_MSR); > if (msr & IMX93_ADC_MSR_CALFAIL_MASK) { > + /* > + * 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 resault of ADC is not that accurate. > + */ > dev_warn(adc->dev, "ADC calibration failed!\n"); > - imx93_adc_power_down(adc); > - return -EAGAIN; > } > > return 0; > > -- > 2.34.1 >