media: hi556: Add support for avdd regulator

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 avdd regulator itself.

Add support for having the driver control the sensor's avdd regulator.
Note this relies on the regulator-core providing a dummy regulator
(which it does by default) on platforms where Linux is not aware of
the avdd regulator.

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/hi556.c b/drivers/media/i2c/hi556.c
index 235caadf02dc784acaf1f4d8f8bcd0182e54a844..b440f386f0622ef777b2d4685ed817c15127d2bb 100644 (file)
--- a/drivers/media/i2c/hi556.c
+++ b/drivers/media/i2c/hi556.c
@@ -9,6 +9,7 @@
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-fwnode.h>
@@ -638,6 +639,7 @@ struct hi556 {
        /* GPIOs, clocks, etc. */
        struct gpio_desc *reset_gpio;
        struct clk *clk;
+       struct regulator *avdd;
 
        /* Current mode */
        const struct hi556_mode *cur_mode;
@@ -1286,8 +1288,17 @@ static int hi556_suspend(struct device *dev)
 {
        struct v4l2_subdev *sd = dev_get_drvdata(dev);
        struct hi556 *hi556 = to_hi556(sd);
+       int ret;
 
        gpiod_set_value_cansleep(hi556->reset_gpio, 1);
+
+       ret = regulator_disable(hi556->avdd);
+       if (ret) {
+               dev_err(dev, "failed to disable avdd: %d\n", ret);
+               gpiod_set_value_cansleep(hi556->reset_gpio, 0);
+               return ret;
+       }
+
        clk_disable_unprepare(hi556->clk);
        return 0;
 }
@@ -1302,6 +1313,13 @@ static int hi556_resume(struct device *dev)
        if (ret)
                return ret;
 
+       ret = regulator_enable(hi556->avdd);
+       if (ret) {
+               dev_err(dev, "failed to enable avdd: %d\n", ret);
+               clk_disable_unprepare(hi556->clk);
+               return ret;
+       }
+
        gpiod_set_value_cansleep(hi556->reset_gpio, 0);
        usleep_range(5000, 5500);
        return 0;
@@ -1337,6 +1355,12 @@ static int hi556_probe(struct i2c_client *client)
                return dev_err_probe(&client->dev, PTR_ERR(hi556->clk),
                                     "failed to get clock\n");
 
+       /* The regulator core will provide a "dummy" regulator if necessary */
+       hi556->avdd = devm_regulator_get(&client->dev, "avdd");
+       if (IS_ERR(hi556->avdd))
+               return dev_err_probe(&client->dev, PTR_ERR(hi556->avdd),
+                                    "failed to get avdd regulator\n");
+
        full_power = acpi_dev_state_d0(&client->dev);
        if (full_power) {
                /* Ensure non ACPI managed resources are enabled */