mfd: adp5585: Add support for a reset pin

Make sure to perform an Hardware reset during probe  if the pin is given
in FW.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20250701-dev-adp5589-fw-v7-20-b1fcfe9e9826@analog.com
Signed-off-by: Lee Jones <lee@kernel.org>

Author: nunojsa

drivers/mfd/adp5585.c

@@ -12,6 +12,7 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/i2c.h>
+#include <linux/gpio/consumer.h>
 #include <linux/mfd/adp5585.h>
 #include <linux/mfd/core.h>
 #include <linux/mod_devicetable.h>
@@ -690,6 +691,7 @@ static int adp5585_i2c_probe(struct i2c_client *i2c)
 {
 	struct regmap_config *regmap_config;
 	struct adp5585_dev *adp5585;
+	struct gpio_desc *gpio;
 	unsigned int id;
 	int ret;
 
@@ -714,6 +716,20 @@ static int adp5585_i2c_probe(struct i2c_client *i2c)
 	if (ret)
 		return ret;
 
+	gpio = devm_gpiod_get_optional(&i2c->dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(gpio))
+		return PTR_ERR(gpio);
+
+	/*
+	 * Note the timings are not documented anywhere in the datasheet. They are just
+	 * reasonable values that work.
+	 */
+	if (gpio) {
+		fsleep(30);
+		gpiod_set_value_cansleep(gpio, 0);
+		fsleep(60);
+	}
+
 	adp5585->regmap = devm_regmap_init_i2c(i2c, regmap_config);
 	if (IS_ERR(adp5585->regmap))
 		return dev_err_probe(&i2c->dev, PTR_ERR(adp5585->regmap),