iio: adc: mcp3911: use devm_regulator_get_enable_read_voltage()

This makes use of the new devm_regulator_get_enable_read_voltage()
helper function to reduce boilerplate code in the MCP3911 ADC driver.

The error message is slightly changed since there are fewer error
return paths.

An extra parameter is added to the config callback to avoid adding
state that is not used outside of the probe() function.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Link: https://patch.msgid.link/20240712-iio-regulator-refactor-round-3-v1-6-835017bae43d@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 16 insertions, 43 deletions

diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c
index 7a32e7a1be9d..5076028f541d 100644
--- a/drivers/iio/adc/mcp3911.c
+++ b/drivers/iio/adc/mcp3911.c
@@ -103,7 +103,7 @@ struct mcp3911_chip_info {
 	const struct iio_chan_spec *channels;
 	unsigned int num_channels;
 
-	int (*config)(struct mcp3911 *adc);
+	int (*config)(struct mcp3911 *adc, bool external_vref);
 	int (*get_osr)(struct mcp3911 *adc, u32 *val);
 	int (*set_osr)(struct mcp3911 *adc, u32 val);
 	int (*enable_offset)(struct mcp3911 *adc, bool enable);
@@ -115,7 +115,6 @@ struct mcp3911_chip_info {
 struct mcp3911 {
 	struct spi_device *spi;
 	struct mutex lock;
-	struct regulator *vref;
 	struct clk *clki;
 	u32 dev_addr;
 	struct iio_trigger *trig;
@@ -385,23 +384,11 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
 	}
 }
 
-static int mcp3911_calc_scale_table(struct mcp3911 *adc)
+static int mcp3911_calc_scale_table(u32 vref_mv)
 {
-	struct device *dev = &adc->spi->dev;
-	u32 ref = MCP3911_INT_VREF_MV;
 	u32 div;
-	int ret;
 	u64 tmp;
 
-	if (adc->vref) {
-		ret = regulator_get_voltage(adc->vref);
-		if (ret < 0) {
-			return dev_err_probe(dev, ret, "failed to get vref voltage\n");
-		}
-
-		ref = ret / 1000;
-	}
-
 	/*
 	 * For 24-bit Conversion
 	 * Raw = ((Voltage)/(Vref) * 2^23 * Gain * 1.5
@@ -412,7 +399,7 @@ static int mcp3911_calc_scale_table(struct mcp3911 *adc)
 	 */
 	for (int i = 0; i < MCP3911_NUM_SCALES; i++) {
 		div = 12582912 * BIT(i);
-		tmp = div_s64((s64)ref * 1000000000LL, div);
+		tmp = div_s64((s64)vref_mv * 1000000000LL, div);
 
 		mcp3911_scale_table[i][0] = 0;
 		mcp3911_scale_table[i][1] = tmp;
@@ -544,7 +531,7 @@ static const struct iio_info mcp3911_info = {
 	.write_raw_get_fmt = mcp3911_write_raw_get_fmt,
 };
 
-static int mcp3911_config(struct mcp3911 *adc)
+static int mcp3911_config(struct mcp3911 *adc, bool external_vref)
 {
 	struct device *dev = &adc->spi->dev;
 	u32 regval;
@@ -555,7 +542,7 @@ static int mcp3911_config(struct mcp3911 *adc)
 		return ret;
 
 	regval &= ~MCP3911_CONFIG_VREFEXT;
-	if (adc->vref) {
+	if (external_vref) {
 		dev_dbg(dev, "use external voltage reference\n");
 		regval |= FIELD_PREP(MCP3911_CONFIG_VREFEXT, 1);
 	} else {
@@ -610,7 +597,7 @@ static int mcp3911_config(struct mcp3911 *adc)
 	return mcp3911_write(adc, MCP3911_REG_GAIN, regval, 1);
 }
 
-static int mcp3910_config(struct mcp3911 *adc)
+static int mcp3910_config(struct mcp3911 *adc, bool external_vref)
 {
 	struct device *dev = &adc->spi->dev;
 	u32 regval;
@@ -621,7 +608,7 @@ static int mcp3910_config(struct mcp3911 *adc)
 		return ret;
 
 	regval &= ~MCP3910_CONFIG1_VREFEXT;
-	if (adc->vref) {
+	if (external_vref) {
 		dev_dbg(dev, "use external voltage reference\n");
 		regval |= FIELD_PREP(MCP3910_CONFIG1_VREFEXT, 1);
 	} else {
@@ -677,11 +664,6 @@ static int mcp3910_config(struct mcp3911 *adc)
 	return adc->chip->enable_offset(adc, 0);
 }
 
-static void mcp3911_cleanup_regulator(void *vref)
-{
-	regulator_disable(vref);
-}
-
 static int mcp3911_set_trigger_state(struct iio_trigger *trig, bool enable)
 {
 	struct mcp3911 *adc = iio_trigger_get_drvdata(trig);
@@ -704,6 +686,8 @@ static int mcp3911_probe(struct spi_device *spi)
 	struct device *dev = &spi->dev;
 	struct iio_dev *indio_dev;
 	struct mcp3911 *adc;
+	bool external_vref;
+	u32 vref_mv;
 	int ret;
 
 	indio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
@@ -714,23 +698,12 @@ static int mcp3911_probe(struct spi_device *spi)
 	adc->spi = spi;
 	adc->chip = spi_get_device_match_data(spi);
 
-	adc->vref = devm_regulator_get_optional(dev, "vref");
-	if (IS_ERR(adc->vref)) {
-		if (PTR_ERR(adc->vref) == -ENODEV) {
-			adc->vref = NULL;
-		} else {
-			return dev_err_probe(dev, PTR_ERR(adc->vref), "failed to get regulator\n");
-		}
+	ret = devm_regulator_get_enable_read_voltage(dev, "vref");
+	if (ret < 0 && ret != -ENODEV)
+		return dev_err_probe(dev, ret, "failed to get vref voltage\n");
 
-	} else {
-		ret = regulator_enable(adc->vref);
-		if (ret)
-			return ret;
-
-		ret = devm_add_action_or_reset(dev, mcp3911_cleanup_regulator, adc->vref);
-		if (ret)
-			return ret;
-	}
+	external_vref = ret != -ENODEV;
+	vref_mv = external_vref ? ret / 1000 : MCP3911_INT_VREF_MV;
 
 	adc->clki = devm_clk_get_enabled(dev, NULL);
 	if (IS_ERR(adc->clki)) {
@@ -755,11 +728,11 @@ static int mcp3911_probe(struct spi_device *spi)
 	}
 	dev_dbg(dev, "use device address %i\n", adc->dev_addr);
 
-	ret = adc->chip->config(adc);
+	ret = adc->chip->config(adc, external_vref);
 	if (ret)
 		return ret;
 
-	ret = mcp3911_calc_scale_table(adc);
+	ret = mcp3911_calc_scale_table(vref_mv);
 	if (ret)
 		return ret;