Patch "iio: adc: ad7192: Correct reference voltage" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

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

    iio: adc: ad7192: Correct reference voltage

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     iio-adc-ad7192-correct-reference-voltage.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6dc31742f152f22496c3860dd9643958e8f6a4df
Author: Alisa-Dariana Roman <alisa.roman@xxxxxxxxxx>
Date:   Sun Sep 24 18:21:48 2023 +0300

    iio: adc: ad7192: Correct reference voltage
    
    [ Upstream commit 7e7dcab620cd6d34939f615cac63fc0ef7e81c72 ]
    
    The avdd and the reference voltage are two different sources but the
    reference voltage was assigned according to the avdd supply.
    
    Add vref regulator structure and set the reference voltage according to
    the vref supply from the devicetree.
    
    In case vref supply is missing, reference voltage is set according to
    the avdd supply for compatibility with old devicetrees.
    
    Fixes: b581f748cce0 ("staging: iio: adc: ad7192: move out of staging")
    Signed-off-by: Alisa-Dariana Roman <alisa.roman@xxxxxxxxxx>
    Cc: stable@xxxxxxxxxxxxxxx
    Link: https://lore.kernel.org/r/20230924152149.41884-1-alisadariana@xxxxxxxxx
    Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
index 6df435e3c4218..31461d46c5941 100644
--- a/drivers/iio/adc/ad7192.c
+++ b/drivers/iio/adc/ad7192.c
@@ -177,6 +177,7 @@ struct ad7192_state {
 	const struct ad7192_chip_info	*chip_info;
 	struct regulator		*avdd;
 	struct regulator		*dvdd;
+	struct regulator		*vref;
 	struct clk			*mclk;
 	u16				int_vref_mv;
 	u32				fclk;
@@ -962,10 +963,30 @@ static int ad7192_probe(struct spi_device *spi)
 	if (ret)
 		return ret;
 
-	ret = regulator_get_voltage(st->avdd);
-	if (ret < 0) {
-		dev_err(&spi->dev, "Device tree error, reference voltage undefined\n");
-		return ret;
+	st->vref = devm_regulator_get_optional(&spi->dev, "vref");
+	if (IS_ERR(st->vref)) {
+		if (PTR_ERR(st->vref) != -ENODEV)
+			return PTR_ERR(st->vref);
+
+		ret = regulator_get_voltage(st->avdd);
+		if (ret < 0)
+			return dev_err_probe(&spi->dev, ret,
+					     "Device tree error, AVdd voltage undefined\n");
+	} else {
+		ret = regulator_enable(st->vref);
+		if (ret) {
+			dev_err(&spi->dev, "Failed to enable specified Vref supply\n");
+			return ret;
+		}
+
+		ret = devm_add_action_or_reset(&spi->dev, ad7192_reg_disable, st->vref);
+		if (ret)
+			return ret;
+
+		ret = regulator_get_voltage(st->vref);
+		if (ret < 0)
+			return dev_err_probe(&spi->dev, ret,
+					     "Device tree error, Vref voltage undefined\n");
 	}
 	st->int_vref_mv = ret / 1000;