Hi,
On 2/3/24 11:15, Jacopo Mondi wrote:
> 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
Yes that is correct.
Regards,
Hans
>
>> 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
>>
>>
>
