[PATCH 5.8 138/177] misc: eeprom: at24: register nvmem only after eeprom is ready to use

Greg Kroah-Hartman
2020-09-15T23:16:30Z

From: Vadym Kochan <vadym.kochan@plvision.eu>

commit 45df80d7605c25055a85fbc5a8446c81c6c0ca24 upstream.

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().

Fixes: cd5676db0574 ("misc: eeprom: at24: support pm_runtime control")
Fixes: b20eb4c1f026 ("eeprom: at24: drop unnecessary label")
Cc: stable@vger.kernel.org
Signed-off-by: Vadym Kochan <vadym.kochan@plvision.eu>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/drivers/misc/eeprom/at24.c
+++ b/drivers/misc/eeprom/at24.c
@@ -692,10 +692,6 @@ static int at24_probe(struct i2c_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
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.