From: Angelo Compagnucci <angelo.compagnu...@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.came...@huawei.com>
Signed-off-by: Angelo Compagnucci <angelo.compagnu...@gmail.com>
Link: 
https://lore.kernel.org/r/20200901093218.1500845-1-angelo.compagnu...@gmail.com
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
Signed-off-by: Sasha Levin <sas...@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 819f260115005..a5a687257c0b8 100644
--- a/drivers/iio/adc/mcp3422.c
+++ b/drivers/iio/adc/mcp3422.c
@@ -148,8 +148,10 @@ 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



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