at24: Support probing while in non-zero ACPI D state

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 in ACPI D state other than 0 (which means fully
powered on).

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Acked-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 305ffad..49ab656 100644 (file)
--- 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 full_power;
        struct regmap *regmap;
        bool writable;
        u8 test_byte;
@@ -747,14 +748,16 @@ 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;
-       }
+       full_power = acpi_dev_state_d0(&client->dev);
+       if (full_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);
 
        at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
@@ -766,15 +769,18 @@ static int at24_probe(struct i2c_client *client)
        }
 
        /*
-        * 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);
-               if (!pm_runtime_status_suspended(dev))
-                       regulator_disable(at24->vcc_reg);
-               return -ENODEV;
+       if (full_power) {
+               err = at24_read(at24, 0, &test_byte, 1);
+               if (err) {
+                       pm_runtime_disable(dev);
+                       if (!pm_runtime_status_suspended(dev))
+                               regulator_disable(at24->vcc_reg);
+                       return -ENODEV;
+               }
        }
 
        pm_runtime_idle(dev);
@@ -794,9 +800,11 @@ 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_d0(&client->dev)) {
+               if (!pm_runtime_status_suspended(&client->dev))
+                       regulator_disable(at24->vcc_reg);
+               pm_runtime_set_suspended(&client->dev);
+       }
 
        return 0;
 }
@@ -833,6 +841,7 @@ static struct i2c_driver at24_driver = {
        .probe_new = at24_probe,
        .remove = at24_remove,
        .id_table = at24_ids,
+       .flags = I2C_DRV_ACPI_WAIVE_D0_PROBE,
 };
 
 static int __init at24_init(void)