media: ov2740: Add support for reset GPIO

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 ThinkPad models with
IPU6 + ov2740 sensor, the sensor driver must control the reset GPIO
and the sensor's clock itself.

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

Reviewed-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

diff --git a/drivers/media/i2c/ov2740.c b/drivers/media/i2c/ov2740.c
index f0be51b343a7c28583257ac3544618fc1d909274..fef1b6f3f316b8338753fa6c3861cff465fc5580 100644 (file)
--- a/drivers/media/i2c/ov2740.c
+++ b/drivers/media/i2c/ov2740.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>
@@ -333,6 +334,9 @@ struct ov2740 {
        struct v4l2_ctrl *hblank;
        struct v4l2_ctrl *exposure;
 
+       /* GPIOs, clocks */
+       struct gpio_desc *reset_gpio;
+
        /* Current mode */
        const struct ov2740_mode *cur_mode;
 
@@ -1061,6 +1065,26 @@ static int ov2740_register_nvmem(struct i2c_client *client,
        return 0;
 }
 
+static int ov2740_suspend(struct device *dev)
+{
+       struct v4l2_subdev *sd = dev_get_drvdata(dev);
+       struct ov2740 *ov2740 = to_ov2740(sd);
+
+       gpiod_set_value_cansleep(ov2740->reset_gpio, 1);
+       return 0;
+}
+
+static int ov2740_resume(struct device *dev)
+{
+       struct v4l2_subdev *sd = dev_get_drvdata(dev);
+       struct ov2740 *ov2740 = to_ov2740(sd);
+
+       gpiod_set_value_cansleep(ov2740->reset_gpio, 0);
+       msleep(20);
+
+       return 0;
+}
+
 static int ov2740_probe(struct i2c_client *client)
 {
        struct device *dev = &client->dev;
@@ -1076,13 +1100,25 @@ static int ov2740_probe(struct i2c_client *client)
        if (!ov2740)
                return -ENOMEM;
 
+       ov2740->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+       if (IS_ERR(ov2740->reset_gpio))
+               return dev_err_probe(dev, PTR_ERR(ov2740->reset_gpio),
+                                    "failed to get reset GPIO\n");
+
        v4l2_i2c_subdev_init(&ov2740->sd, client, &ov2740_subdev_ops);
        ov2740->sd.internal_ops = &ov2740_internal_ops;
        full_power = acpi_dev_state_d0(&client->dev);
        if (full_power) {
-               ret = ov2740_identify_module(ov2740);
+               /* ACPI does not always clear the reset GPIO / enable the clock */
+               ret = ov2740_resume(dev);
                if (ret)
-                       return dev_err_probe(dev, ret, "failed to find sensor\n");
+                       return dev_err_probe(dev, ret, "failed to power on sensor\n");
+
+               ret = ov2740_identify_module(ov2740);
+               if (ret) {
+                       dev_err_probe(dev, ret, "failed to find sensor\n");
+                       goto probe_error_power_off;
+               }
        }
 
        ov2740->cur_mode = &supported_modes[0];
@@ -1136,9 +1172,16 @@ static int ov2740_probe(struct i2c_client *client)
 probe_error_v4l2_ctrl_handler_free:
        v4l2_ctrl_handler_free(ov2740->sd.ctrl_handler);
 
+probe_error_power_off:
+       if (full_power)
+               ov2740_suspend(dev);
+
        return ret;
 }
 
+static DEFINE_RUNTIME_DEV_PM_OPS(ov2740_pm_ops, ov2740_suspend, ov2740_resume,
+                                NULL);
+
 static const struct acpi_device_id ov2740_acpi_ids[] = {
        {"INT3474"},
        {}
@@ -1150,6 +1193,7 @@ static struct i2c_driver ov2740_i2c_driver = {
        .driver = {
                .name = "ov2740",
                .acpi_match_table = ov2740_acpi_ids,
+               .pm = pm_sleep_ptr(&ov2740_pm_ops),
        },
        .probe = ov2740_probe,
        .remove = ov2740_remove,