media: i2c: ov2740: get OTP data ready before nvmem registration

The OTP data was not ready after registered as nvmem device, it is
risky as the nvmem read may happen once the device exists, this patch
get the OTP data ready before registering the nvmem device. OTP data
missing should not break the normal camera sensor probe, so use a
warning instead of an error message.
Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Signed-off-by: Qingwu Zhang <qingwu.zhang@intel.com>
Suggested-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/i2c/ov2740.c

@@ -1018,6 +1018,10 @@ static int ov2740_register_nvmem(struct i2c_client *client)
 	if (!nvm)
 		return -ENOMEM;
 
+	nvm->nvm_buffer = devm_kzalloc(dev, CUSTOMER_USE_OTP_SIZE, GFP_KERNEL);
+	if (!nvm->nvm_buffer)
+		return -ENOMEM;
+
 	regmap_config.val_bits = 8;
 	regmap_config.reg_bits = 16;
 	regmap_config.disable_locking = true;
@@ -1027,6 +1031,12 @@ static int ov2740_register_nvmem(struct i2c_client *client)
 
 	nvm->regmap = regmap;
 
+	ret = ov2740_load_otp_data(client, nvm);
+	if (ret) {
+		dev_err(dev, "failed to load OTP data, ret %d\n", ret);
+		return ret;
+	}
+
 	nvmem_config.name = dev_name(dev);
 	nvmem_config.dev = dev;
 	nvmem_config.read_only = true;
@@ -1042,18 +1052,8 @@ static int ov2740_register_nvmem(struct i2c_client *client)
 	nvmem_config.size = CUSTOMER_USE_OTP_SIZE;
 
 	nvm->nvmem = devm_nvmem_register(dev, &nvmem_config);
-	if (IS_ERR(nvm->nvmem))
-		return PTR_ERR(nvm->nvmem);
 
-	nvm->nvm_buffer = devm_kzalloc(dev, CUSTOMER_USE_OTP_SIZE, GFP_KERNEL);
-	if (!nvm->nvm_buffer)
-		return -ENOMEM;
-
-	ret = ov2740_load_otp_data(client, nvm);
-	if (ret)
-		dev_err(dev, "failed to load OTP data, ret %d\n", ret);
-
-	return ret;
+	return PTR_ERR_OR_ZERO(nvm->nvmem);
 }
 
 static int ov2740_probe(struct i2c_client *client)
@@ -1107,7 +1107,7 @@ static int ov2740_probe(struct i2c_client *client)
 
 	ret = ov2740_register_nvmem(client);
 	if (ret)
-		dev_err(&client->dev, "register nvmem failed, ret %d\n", ret);
+		dev_warn(&client->dev, "register nvmem failed, ret %d\n", ret);
 
 	/*
 	 * Device is already turned on by i2c-core with ACPI domain PM.