[bug report] mfd: lp87565: Handle optional reset pin

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Luca Ceresoli,

The patch 50e4d7a2a667: "mfd: lp87565: Handle optional reset pin"
from Feb 26, 2021, leads to the following Smatch static checker
warning:

	drivers/mfd/lp87565.c:76 lp87565_probe()
	warn: 'lp87565->reset_gpio' could be an error pointer

drivers/mfd/lp87565.c
    46 static int lp87565_probe(struct i2c_client *client,
    47                          const struct i2c_device_id *ids)
    48 {
    49         struct lp87565 *lp87565;
    50         const struct of_device_id *of_id;
    51         int ret;
    52         unsigned int otpid;
    53 
    54         lp87565 = devm_kzalloc(&client->dev, sizeof(*lp87565), GFP_KERNEL);
    55         if (!lp87565)
    56                 return -ENOMEM;
    57 
    58         lp87565->dev = &client->dev;
    59 
    60         lp87565->regmap = devm_regmap_init_i2c(client, &lp87565_regmap_config);
    61         if (IS_ERR(lp87565->regmap)) {
    62                 ret = PTR_ERR(lp87565->regmap);
    63                 dev_err(lp87565->dev,
    64                         "Failed to initialize register map: %d\n", ret);
    65                 return ret;
    66         }
    67 
    68         lp87565->reset_gpio = devm_gpiod_get_optional(lp87565->dev, "reset",
    69                                                       GPIOD_OUT_LOW);
    70         if (IS_ERR(lp87565->reset_gpio)) {
    71                 ret = PTR_ERR(lp87565->reset_gpio);
    72                 if (ret == -EPROBE_DEFER)
    73                         return ret;

Only "ret = -EPROBE_DEFER" is handled.  Other error pointer will lead to
a crash.

    74         }
    75 
--> 76         if (lp87565->reset_gpio) {
    77                 gpiod_set_value_cansleep(lp87565->reset_gpio, 1);
    78                 /* The minimum assertion time is undocumented, just guess */
    79                 usleep_range(2000, 4000);
    80 
    81                 gpiod_set_value_cansleep(lp87565->reset_gpio, 0);
    82                 /* Min 1.2 ms before first I2C transaction */
    83                 usleep_range(1500, 3000);
    84         }
    85 
    86         ret = regmap_read(lp87565->regmap, LP87565_REG_OTP_REV, &otpid);
    87         if (ret) {
    88                 dev_err(lp87565->dev, "Failed to read OTP ID\n");
    89                 return ret;
    90         }
    91 
    92         lp87565->rev = otpid & LP87565_OTP_REV_OTP_ID;
    93 
    94         of_id = of_match_device(of_lp87565_match_table, &client->dev);
    95         if (of_id)
    96                 lp87565->dev_type = (enum lp87565_device_type)of_id->data;
    97 
    98         i2c_set_clientdata(client, lp87565);
    99 
    100         return devm_mfd_add_devices(lp87565->dev, PLATFORM_DEVID_AUTO,
    101                                     lp87565_cells, ARRAY_SIZE(lp87565_cells),
    102                                     NULL, 0, NULL);
    103 }

regards,
dan carpenter