[PATCH v3 3/3] misc: eeprom: at24: register nvmem only after eeprom is ready to use

[Vadym Kochan]

During nvmem_register() the nvmem core sends notifications when:

    - cell added
    - nvmem added

and during these notifications some callback func may access the nvmem
device, which will fail in case of at24 eeprom because regulator and pm
are enabled after nvmem_register().

Signed-off-by: Vadym Kochan <vadym.koc...@plvision.eu>
---
v3:
    1) at24 driver enables regulator and pm state machine after nvmem
       registration which does not allow to use it on handing NVMEM_PRE_ADD 
event.

 drivers/misc/eeprom/at24.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/eeprom/at24.c b/drivers/misc/eeprom/at24.c
index 2591c21b2b5d..26a23abc053d 100644
--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -692,10 +692,6 @@ static int at24_probe(struct i2c_client *client)
        nvmem_config.word_size = 1;
        nvmem_config.size = byte_len;
 
-       at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
-       if (IS_ERR(at24->nvmem))
-               return PTR_ERR(at24->nvmem);
-
        i2c_set_clientdata(client, at24);
 
        err = regulator_enable(at24->vcc_reg);
@@ -708,6 +704,13 @@ static int at24_probe(struct i2c_client *client)
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);
 
+       at24->nvmem = devm_nvmem_register(dev, &nvmem_config);
+       if (IS_ERR(at24->nvmem)) {
+               pm_runtime_disable(dev);
+               regulator_disable(at24->vcc_reg);
+               return PTR_ERR(at24->nvmem);
+       }
+
        /*
         * Perform a one-byte test read to verify that the
         * chip is functional.
-- 
2.17.1