From: Ariana Lazar <ariana.lazar@microchip.com>
Date: Thu, 4 Jun 2026 13:46:47 +0000 (+0300)
Subject: iio: dac: mcp47feb02: Fix passing uninitialized vref1_uV for no Vref1 case
X-Git-Tag: v7.2-rc3~3^2^2~25
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e74c0d0eef7e1fa9fd387b81b2787b4581e0b11c;p=thirdparty%2Fkernel%2Fstable.git

iio: dac: mcp47feb02: Fix passing uninitialized vref1_uV for no Vref1 case

Ensure that if a device has Vref1 but reading the regulator returns an
error, mcp47feb02_init_ctrl_regs() is not called with an uninitialized
vref1_uV value. Also add a device_property_present() check for the Vref1
supply before reading the regulator.

Fixes: dd154646d292 ("iio: dac: mcp47feb02: Fix Vref validation [1-999] case")
Reported-by: Dan Carpenter <error27@gmail.com>
Closes: https://lore.kernel.org/all/adiPnla0M5EzvgD-@stanley.mountain/
Signed-off-by: Ariana Lazar <ariana.lazar@microchip.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---

diff --git a/drivers/iio/dac/mcp47feb02.c b/drivers/iio/dac/mcp47feb02.c
index 217f78e44af12..a823c2a673a26 100644
--- a/drivers/iio/dac/mcp47feb02.c
+++ b/drivers/iio/dac/mcp47feb02.c
@@ -1136,26 +1136,33 @@ static int mcp47feb02_probe(struct i2c_client *client)
 
 	vdd_uV = ret;
 
-	ret = devm_regulator_get_enable_read_voltage(dev, "vref");
-	if (ret > 0) {
-		vref_uV = ret;
+	if (device_property_present(dev, "vref-supply")) {
+		vref_uV = devm_regulator_get_enable_read_voltage(dev, "vref");
+		if (vref_uV < 0)
+			return vref_uV;
+
+		if (vref_uV == 0)
+			return dev_err_probe(dev, -EINVAL, "Vref is 0 uV.\n");
+
 		data->use_vref = true;
 	} else {
 		vref_uV = 0;
-		dev_dbg(dev, "using internal band gap as voltage reference.\n");
-		dev_dbg(dev, "Vref is unavailable.\n");
+		dev_dbg(dev, "Using internal band gap as voltage reference.\n");
 	}
 
-	if (chip_features->have_ext_vref1) {
-		ret = devm_regulator_get_enable_read_voltage(dev, "vref1");
-		if (ret > 0) {
-			vref1_uV = ret;
-			data->use_vref1 = true;
-		} else {
-			vref1_uV = 0;
-			dev_dbg(dev, "using internal band gap as voltage reference 1.\n");
-			dev_dbg(dev, "Vref1 is unavailable.\n");
-		}
+	if (chip_features->have_ext_vref1 &&
+	    device_property_present(dev, "vref1-supply")) {
+		vref1_uV = devm_regulator_get_enable_read_voltage(dev, "vref1");
+		if (vref1_uV < 0)
+			return vref1_uV;
+
+		if (vref1_uV == 0)
+			return dev_err_probe(dev, -EINVAL, "Vref1 is 0 uV.\n");
+
+		data->use_vref1 = true;
+	} else {
+		vref1_uV = 0;
+		dev_dbg(dev, "Using internal band gap as voltage reference 1.\n");
 	}
 
 	ret = mcp47feb02_init_ctrl_regs(data);