[PATCH resend 2/4] media: hi556: Add support for reset GPIO

[Hans de Goede <hdegoede@redhat.com>]

On some ACPI platforms, such as Chromebooks the ACPI methods to
change the power-state (_PS0 and _PS3) fully take care of powering
on/off the sensor.

On other ACPI platforms, such as e.g. various HP models with IPU6 +
hi556 sensor, the sensor driver must control the reset GPIO itself.

Add support for having the driver control an optional reset GPIO.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 drivers/media/i2c/hi556.c | 45 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

diff --git a/drivers/media/i2c/hi556.c b/drivers/media/i2c/hi556.c
index 96bae9914d52..f5a39b83598b 100644
--- a/drivers/media/i2c/hi556.c
+++ b/drivers/media/i2c/hi556.c
@@ -4,6 +4,7 @@
 #include <asm/unaligned.h>
 #include <linux/acpi.h>
 #include <linux/delay.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
@@ -633,6 +634,9 @@ struct hi556 {
 	struct v4l2_ctrl *hblank;
 	struct v4l2_ctrl *exposure;
 
+	/* GPIOs, clocks, etc. */
+	struct gpio_desc *reset_gpio;
+
 	/* Current mode */
 	const struct hi556_mode *cur_mode;
 
@@ -1276,6 +1280,25 @@ static void hi556_remove(struct i2c_client *client)
 	mutex_destroy(&hi556->mutex);
 }
 
+static int hi556_suspend(struct device *dev)
+{
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
+	struct hi556 *hi556 = to_hi556(sd);
+
+	gpiod_set_value_cansleep(hi556->reset_gpio, 1);
+	return 0;
+}
+
+static int hi556_resume(struct device *dev)
+{
+	struct v4l2_subdev *sd = dev_get_drvdata(dev);
+	struct hi556 *hi556 = to_hi556(sd);
+
+	gpiod_set_value_cansleep(hi556->reset_gpio, 0);
+	usleep_range(5000, 5500);
+	return 0;
+}
+
 static int hi556_probe(struct i2c_client *client)
 {
 	struct hi556 *hi556;
@@ -1295,12 +1318,24 @@ static int hi556_probe(struct i2c_client *client)
 
 	v4l2_i2c_subdev_init(&hi556->sd, client, &hi556_subdev_ops);
 
+	hi556->reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
+						    GPIOD_OUT_HIGH);
+	if (IS_ERR(hi556->reset_gpio))
+		return dev_err_probe(&client->dev, PTR_ERR(hi556->reset_gpio),
+				     "failed to get reset GPIO\n");
+
 	full_power = acpi_dev_state_d0(&client->dev);
 	if (full_power) {
+		/* Ensure non ACPI managed resources are enabled */
+		ret = hi556_resume(&client->dev);
+		if (ret)
+			return dev_err_probe(&client->dev, ret,
+					     "failed to power on sensor\n");
+
 		ret = hi556_identify_module(hi556);
 		if (ret) {
 			dev_err(&client->dev, "failed to find sensor: %d", ret);
-			return ret;
+			goto probe_error_power_off;
 		}
 	}
 
@@ -1345,9 +1380,16 @@ static int hi556_probe(struct i2c_client *client)
 	v4l2_ctrl_handler_free(hi556->sd.ctrl_handler);
 	mutex_destroy(&hi556->mutex);
 
+probe_error_power_off:
+	if (full_power)
+		hi556_suspend(&client->dev);
+
 	return ret;
 }
 
+static DEFINE_RUNTIME_DEV_PM_OPS(hi556_pm_ops, hi556_suspend, hi556_resume,
+				 NULL);
+
 #ifdef CONFIG_ACPI
 static const struct acpi_device_id hi556_acpi_ids[] = {
 	{"INT3537"},
@@ -1361,6 +1403,7 @@ static struct i2c_driver hi556_i2c_driver = {
 	.driver = {
 		.name = "hi556",
 		.acpi_match_table = ACPI_PTR(hi556_acpi_ids),
+		.pm = pm_sleep_ptr(&hi556_pm_ops),
 	},
 	.probe = hi556_probe,
 	.remove = hi556_remove,
-- 
2.44.0