hwmon: (pmbus_core) Fix NULL pointer dereference

Pass i2c_client to _pmbus_is_enabled to drop the assumption
that a regulator device is passed in.

This will fix the issue of a NULL pointer dereference when called from
_pmbus_get_flags.

Fixes: df5f6b6af01c ("hwmon: (pmbus/core) Generalise pmbus get status")
Cc: stable@vger.kernel.org # v6.4
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Link: https://lore.kernel.org/r/20230725125428.3966803-2-Naresh.Solanki@9elements.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 42fb728..30aeb59 100644 (file)
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -2745,9 +2745,8 @@ static const struct pmbus_status_category __maybe_unused pmbus_status_flag_map[]
        },
 };
 
-static int _pmbus_is_enabled(struct device *dev, u8 page)
+static int _pmbus_is_enabled(struct i2c_client *client, u8 page)
 {
-       struct i2c_client *client = to_i2c_client(dev->parent);
        int ret;
 
        ret = _pmbus_read_byte_data(client, page, PMBUS_OPERATION);
@@ -2758,14 +2757,13 @@ static int _pmbus_is_enabled(struct device *dev, u8 page)
        return !!(ret & PB_OPERATION_CONTROL_ON);
 }
 
-static int __maybe_unused pmbus_is_enabled(struct device *dev, u8 page)
+static int __maybe_unused pmbus_is_enabled(struct i2c_client *client, u8 page)
 {
-       struct i2c_client *client = to_i2c_client(dev->parent);
        struct pmbus_data *data = i2c_get_clientdata(client);
        int ret;
 
        mutex_lock(&data->update_lock);
-       ret = _pmbus_is_enabled(dev, page);
+       ret = _pmbus_is_enabled(client, page);
        mutex_unlock(&data->update_lock);
 
        return ret;
@@ -2844,7 +2842,7 @@ static int _pmbus_get_flags(struct pmbus_data *data, u8 page, unsigned int *flag
        if (status < 0)
                return status;
 
-       if (_pmbus_is_enabled(dev, page)) {
+       if (_pmbus_is_enabled(client, page)) {
                if (status & PB_STATUS_OFF) {
                        *flags |= REGULATOR_ERROR_FAIL;
                        *event |= REGULATOR_EVENT_FAIL;
@@ -2898,7 +2896,10 @@ static int __maybe_unused pmbus_get_flags(struct pmbus_data *data, u8 page, unsi
 #if IS_ENABLED(CONFIG_REGULATOR)
 static int pmbus_regulator_is_enabled(struct regulator_dev *rdev)
 {
-       return pmbus_is_enabled(rdev_get_dev(rdev), rdev_get_id(rdev));
+       struct device *dev = rdev_get_dev(rdev);
+       struct i2c_client *client = to_i2c_client(dev->parent);
+
+       return pmbus_is_enabled(client, rdev_get_id(rdev));
 }
 
 static int _pmbus_regulator_on_off(struct regulator_dev *rdev, bool enable)