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