mfd: pm8008: Deassert reset on probe

Request and deassert any (optional) reset gpio during probe in case it
has been left asserted by the boot firmware.

Note the reset line is not asserted to avoid reverting to the default
I2C address in case the firmware has configured an alternate address.
Tested-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20240608155526.12996-4-johan+linaro@kernel.orgSigned-off-by: Lee Jones <lee@kernel.org>

drivers/mfd/qcom-pm8008.c

@@ -4,6 +4,7 @@
  */
 
 #include <linux/bitops.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
@@ -156,6 +157,7 @@ static struct regmap_config qcom_mfd_regmap_cfg = {
 static int pm8008_probe(struct i2c_client *client)
 {
 	struct regmap_irq_chip_data *irq_data;
+	struct gpio_desc *reset;
 	int rc;
 	struct device *dev;
 	struct regmap *regmap;
@@ -167,6 +169,16 @@ static int pm8008_probe(struct i2c_client *client)
 
 	i2c_set_clientdata(client, regmap);
 
+	reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(reset))
+		return PTR_ERR(reset);
+
+	/*
+	 * The PMIC does not appear to require a post-reset delay, but wait
+	 * for a millisecond for now anyway.
+	 */
+	usleep_range(1000, 2000);
+
 	if (of_property_read_bool(dev->of_node, "interrupt-controller")) {
 		rc = devm_regmap_add_irq_chip(dev, regmap, client->irq,
 				IRQF_SHARED, 0, &pm8008_irq_chip, &irq_data);