regulator: pca9450: Add SD_VSEL GPIO for LDO5

LDO5 has two separate control registers. LDO5CTRL_L is used if the
input signal SD_VSEL is low and LDO5CTRL_H if it is high.
The current driver implementation only uses LDO5CTRL_H. To make this
work on boards that have SD_VSEL connected to a GPIO, we add support
for specifying an optional GPIO and setting it to high at probe time.

In the future we might also want to add support for boards that have
SD_VSEL set to a fixed low level. In this case we need to change the
driver to be able to use the LDO5CTRL_L register.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Link: https://lore.kernel.org/r/20210211105534.38972-1-frieder.schrempf@kontron.de
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/pca9450-regulator.c

@@ -5,6 +5,7 @@
  */
 
 #include <linux/err.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -32,6 +33,7 @@ struct pca9450_regulator_desc {
 struct pca9450 {
 	struct device *dev;
 	struct regmap *regmap;
+	struct gpio_desc *sd_vsel_gpio;
 	enum pca9450_chip_type type;
 	unsigned int rcnt;
 	int irq;
@@ -795,6 +797,18 @@ static int pca9450_i2c_probe(struct i2c_client *i2c,
 		return ret;
 	}
 
+	/*
+	 * The driver uses the LDO5CTRL_H register to control the LDO5 regulator.
+	 * This is only valid if the SD_VSEL input of the PMIC is high. Let's
+	 * check if the pin is available as GPIO and set it to high.
+	 */
+	pca9450->sd_vsel_gpio = gpiod_get_optional(pca9450->dev, "sd-vsel", GPIOD_OUT_HIGH);
+
+	if (IS_ERR(pca9450->sd_vsel_gpio)) {
+		dev_err(&i2c->dev, "Failed to get SD_VSEL GPIO\n");
+		return ret;
+	}
+
 	dev_info(&i2c->dev, "%s probed.\n",
 		type == PCA9450_TYPE_PCA9450A ? "pca9450a" : "pca9450bc");