From: Haibo Chen haibo.chen@nxp.com
[ Upstream commit c87b7b12f48db86ac9909894f4dc0107d7df6375 ]
The original logic to get mma8452_data is wrong, the *dev point to the device belong to iio_dev. we can't use this dev to find the correct i2c_client. The original logic happen to work because it finally use dev->driver_data to get iio_dev. Here use the API to_i2c_client() is wrong and make reader confuse. To correct the logic, it should be like this
struct mma8452_data *data = iio_priv(dev_get_drvdata(dev));
But after commit 8b7651f25962 ("iio: iio_device_alloc(): Remove unnecessary self drvdata"), the upper logic also can't work. When try to show the avialable scale in userspace, will meet kernel dump, kernel handle NULL pointer dereference.
So use dev_to_iio_dev() to correct the logic.
Dual fixes tags as the second reflects when the bug was exposed, whilst the first reflects when the original bug was introduced.
Fixes: c3cdd6e48e35 ("iio: mma8452: refactor for seperating chip specific data") Fixes: 8b7651f25962 ("iio: iio_device_alloc(): Remove unnecessary self drvdata") Signed-off-by: Haibo Chen haibo.chen@nxp.com Reviewed-by: Martin Kepplinger martink@posteo.de Cc: Stable@vger.kernel.org Link: https://lore.kernel.org/r/1645497741-5402-1-git-send-email-haibo.chen@nxp.co... Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iio/accel/mma8452.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c index 373b59557afe..1f46a73aafea 100644 --- a/drivers/iio/accel/mma8452.c +++ b/drivers/iio/accel/mma8452.c @@ -380,8 +380,8 @@ static ssize_t mma8452_show_scale_avail(struct device *dev, struct device_attribute *attr, char *buf) { - struct mma8452_data *data = iio_priv(i2c_get_clientdata( - to_i2c_client(dev))); + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct mma8452_data *data = iio_priv(indio_dev);
return mma8452_show_int_plus_micros(buf, data->chip_info->mma_scales, ARRAY_SIZE(data->chip_info->mma_scales));