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 | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)
diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 518945b2f7374..a56cd6a6105c0 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -565,6 +565,7 @@ 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;
@@ -702,19 +703,24 @@ static int at24_probe(struct i2c_client *client)
i2c_set_clientdata(client, at24);
- /* enable runtime pm */
- pm_runtime_set_active(dev);
+ low_power = acpi_dev_low_power_state_probe(&client->dev);
+ if (!low_power)
+ 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);
- pm_runtime_idle(dev);
- if (err) {
- pm_runtime_disable(dev);
- return -ENODEV;
+ if (!low_power) {
+ err = at24_read(at24, 0, &test_byte, 1);
+ pm_runtime_idle(dev);
+ if (err) {
+ pm_runtime_disable(dev);
+ return -ENODEV;
+ }
}
dev_info(dev, "%u byte %s EEPROM, %s, %u bytes/write\n",
@@ -726,8 +732,12 @@ static int at24_probe(struct i2c_client *client)
static int at24_remove(struct i2c_client *client)
{
+ bool low_power;
+
pm_runtime_disable(&client->dev);
- pm_runtime_set_suspended(&client->dev);
+ low_power = acpi_dev_low_power_state_probe(&client->dev);
+ if (!low_power)
+ pm_runtime_set_suspended(&client->dev);
return 0;
}
@@ -735,6 +745,7 @@ static int at24_remove(struct i2c_client *client)
static struct i2c_driver at24_driver = {
.driver = {
.name = "at24",
+ .probe_low_power = true,
.of_match_table = at24_of_match,
.acpi_match_table = ACPI_PTR(at24_acpi_ids),
},
--
2.20.1
