On Thu, Sep 3, 2020 at 10:15 AM Sakari Ailus
<sakari.ailus@xxxxxxxxxxxxxxx> wrote:
>
> In certain use cases (where the chip is part of a camera module, and the
> camera module is wired together with a camera privacy LED), powering on
> the device during probe is undesirable. Add support for the at24 to
> execute probe while being powered off. For this to happen, a hint in form
> of a device property is required from the firmware.
>
> Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
> ---
> drivers/misc/eeprom/at24.c | 43 +++++++++++++++++++++++---------------
> 1 file changed, 26 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
> index 8f5de5f10bbea..2d24e33788d7d 100644
> --- a/drivers/misc/eeprom/at24.c
> +++ b/drivers/misc/eeprom/at24.c
> @@ -595,6 +595,7 @@ static int at24_probe(struct i2c_client *client)
> bool i2c_fn_i2c, i2c_fn_block;
> unsigned int i, num_addresses;
> struct at24_data *at24;
> + bool low_power;
> struct regmap *regmap;
> bool writable;
> u8 test_byte;
> @@ -733,25 +734,30 @@ static int at24_probe(struct i2c_client *client)
>
> i2c_set_clientdata(client, at24);
>
> - err = regulator_enable(at24->vcc_reg);
> - if (err) {
> - dev_err(dev, "Failed to enable vcc regulator\n");
> - return err;
> - }
> + low_power = acpi_dev_state_low_power(&client->dev);
> + if (!low_power) {
> + err = regulator_enable(at24->vcc_reg);
> + if (err) {
> + dev_err(dev, "Failed to enable vcc regulator\n");
> + return err;
> + }
>
> - /* enable runtime pm */
> - pm_runtime_set_active(dev);
> + pm_runtime_set_active(dev);
> + }
> pm_runtime_enable(dev);
>
> /*
> - * Perform a one-byte test read to verify that the
> - * chip is functional.
> + * Perform a one-byte test read to verify that the chip is functional,
> + * unless powering on the device is to be avoided during probe (i.e.
> + * it's powered off right now).
> */
> - err = at24_read(at24, 0, &test_byte, 1);
> - if (err) {
> - pm_runtime_disable(dev);
> - regulator_disable(at24->vcc_reg);
> - return -ENODEV;
> + if (!low_power) {
> + err = at24_read(at24, 0, &test_byte, 1);
> + if (err) {
> + pm_runtime_disable(dev);
> + regulator_disable(at24->vcc_reg);
> + return -ENODEV;
> + }
> }
>
> pm_runtime_idle(dev);
> @@ -771,9 +777,11 @@ static int at24_remove(struct i2c_client *client)
> struct at24_data *at24 = i2c_get_clientdata(client);
>
> pm_runtime_disable(&client->dev);
> - if (!pm_runtime_status_suspended(&client->dev))
> - regulator_disable(at24->vcc_reg);
> - pm_runtime_set_suspended(&client->dev);
> + if (!acpi_dev_state_low_power(&client->dev)) {
> + if (!pm_runtime_status_suspended(&client->dev))
> + regulator_disable(at24->vcc_reg);
> + pm_runtime_set_suspended(&client->dev);
> + }
>
> return 0;
> }
> @@ -810,6 +818,7 @@ static struct i2c_driver at24_driver = {
> .probe_new = at24_probe,
> .remove = at24_remove,
> .id_table = at24_ids,
> + .flags = I2C_DRV_FL_ALLOW_LOW_POWER_PROBE,
> };
>
> static int __init at24_init(void)
> --
> 2.20.1
>
This currently conflicts with the fix I queued for at24 for v5.9.
Which tree is going to take this series?
Bartosz
