Hi Hans
On Thu, Feb 01, 2024 at 10:58:41PM +0100, Hans de Goede wrote:
> 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.
>
Please excuse the question from an ACPI illiterate, but does it mean
that, in example:
1) Chromebooks: you get a dummy
2) HP: you get an actual regulator reference
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> drivers/media/i2c/hi556.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/drivers/media/i2c/hi556.c b/drivers/media/i2c/hi556.c
> index fb6ba6984e38..90eff282a6e2 100644
> --- 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;
> @@ -1287,8 +1289,17 @@ 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);
I understand in error paths you're supposed to reverse the previously
done operations, but, as this is a reset, isn't it better to keep the
reset enabled since we're suspending anyway ?
> + return ret;
> + }
> +
> clk_disable_unprepare(hi556->clk);
> return 0;
> }
> @@ -1303,6 +1314,13 @@ 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;
> @@ -1338,6 +1356,12 @@ 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 */
> --
> 2.43.0
>
>
