patch "iio: adc: stm32: fix vrefint wrong calibration value handling" added to char-misc-linus

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    iio: adc: stm32: fix vrefint wrong calibration value handling

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


From bc05f30fc24705cd023f38659303376eaa5767df Mon Sep 17 00:00:00 2001
From: Olivier Moysan <olivier.moysan@foss.st.com>
Date: Thu, 9 Jun 2022 11:58:56 +0200
Subject: iio: adc: stm32: fix vrefint wrong calibration value handling

If the vrefint calibration is zero, the vrefint channel output value
cannot be computed. Currently, in such case, the raw conversion value
is returned, which is not relevant.
Do not expose the vrefint channel when the output value cannot be
computed, instead.

Fixes: 0e346b2cfa85 ("iio: adc: stm32-adc: add vrefint calibration support")
Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20220609095856.376961-1-olivier.moysan@foss.st.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/adc/stm32-adc.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 8c5f05f593ab..11ef873d6453 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -1365,7 +1365,7 @@ static int stm32_adc_read_raw(struct iio_dev *indio_dev,
 		else
 			ret = -EINVAL;
 
-		if (mask == IIO_CHAN_INFO_PROCESSED && adc->vrefint.vrefint_cal)
+		if (mask == IIO_CHAN_INFO_PROCESSED)
 			*val = STM32_ADC_VREFINT_VOLTAGE * adc->vrefint.vrefint_cal / *val;
 
 		iio_device_release_direct_mode(indio_dev);
@@ -1969,10 +1969,10 @@ static int stm32_adc_populate_int_ch(struct iio_dev *indio_dev, const char *ch_n
 
 	for (i = 0; i < STM32_ADC_INT_CH_NB; i++) {
 		if (!strncmp(stm32_adc_ic[i].name, ch_name, STM32_ADC_CH_SZ)) {
-			adc->int_ch[i] = chan;
-
-			if (stm32_adc_ic[i].idx != STM32_ADC_INT_CH_VREFINT)
-				continue;
+			if (stm32_adc_ic[i].idx != STM32_ADC_INT_CH_VREFINT) {
+				adc->int_ch[i] = chan;
+				break;
+			}
 
 			/* Get calibration data for vrefint channel */
 			ret = nvmem_cell_read_u16(&indio_dev->dev, "vrefint", &vrefint);
@@ -1980,10 +1980,15 @@ static int stm32_adc_populate_int_ch(struct iio_dev *indio_dev, const char *ch_n
 				return dev_err_probe(indio_dev->dev.parent, ret,
 						     "nvmem access error\n");
 			}
-			if (ret == -ENOENT)
-				dev_dbg(&indio_dev->dev, "vrefint calibration not found\n");
-			else
-				adc->vrefint.vrefint_cal = vrefint;
+			if (ret == -ENOENT) {
+				dev_dbg(&indio_dev->dev, "vrefint calibration not found. Skip vrefint channel\n");
+				return ret;
+			} else if (!vrefint) {
+				dev_dbg(&indio_dev->dev, "Null vrefint calibration value. Skip vrefint channel\n");
+				return -ENOENT;
+			}
+			adc->int_ch[i] = chan;
+			adc->vrefint.vrefint_cal = vrefint;
 		}
 	}
 
@@ -2020,7 +2025,9 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
 			}
 			strncpy(adc->chan_name[val], name, STM32_ADC_CH_SZ);
 			ret = stm32_adc_populate_int_ch(indio_dev, name, val);
-			if (ret)
+			if (ret == -ENOENT)
+				continue;
+			else if (ret)
 				goto err;
 		} else if (ret != -EINVAL) {
 			dev_err(&indio_dev->dev, "Invalid label %d\n", ret);
-- 
2.36.1