[PATCH 5.4 017/132] iio: adc: mcp3422: fix locking on error path

Greg Kroah-Hartman
2020-09-16T00:14:13Z

From: Angelo Compagnucci <angelo.compagnucci@gmail.com>

[ Upstream commit a139ffa40f0c24b753838b8ef3dcf6ad10eb7854 ]

Reading from the chip should be unlocked on error path else the lock
could never being released.

Fixes: 07914c84ba30 ("iio: adc: Add driver for Microchip MCP3422/3/4 high resolution ADC")
Fixes: 3f1093d83d71 ("iio: adc: mcp3422: fix locking scope")
Acked-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Angelo Compagnucci <angelo.compagnucci@gmail.com>
Link: https://lore.kernel.org/r/20200901093218.1500845-1-angelo.compagnucci@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/adc/mcp3422.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/mcp3422.c b/drivers/iio/adc/mcp3422.c
index ea24d7c58b127..4d03b1f265d9c 100644
--- a/drivers/iio/adc/mcp3422.c
+++ b/drivers/iio/adc/mcp3422.c
@@ -144,8 +144,10 @@ static int mcp3422_read_channel(struct mcp3422 *adc,
config &= ~MCP3422_PGA_MASK;
config |= MCP3422_PGA_VALUE(adc->pga[req_channel]);
ret = mcp3422_update_config(adc, config);
- if (ret < 0)
+ if (ret < 0) {
+ mutex_unlock(&adc->lock);
return ret;
+ }
msleep(mcp3422_read_times[MCP3422_SAMPLE_RATE(adc->config)]);
}

--
2.25.1