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authorDimitri Fedrau <dima.fedrau@gmail.com>2024-04-24 20:59:10 +0200
committerJonathan Cameron <jonathan.cameron@huawei.com>2024-05-03 12:48:56 +0200
commit827dca3129708a8465bde90c86c2e3c38e62dd4f (patch)
tree04274c6c1e843e6b07de683cacc3dc405931d2ac
parentiio: adc: PAC1934: fix accessing out of bounds array index (diff)
downloadlinux-827dca3129708a8465bde90c86c2e3c38e62dd4f.tar.xz
linux-827dca3129708a8465bde90c86c2e3c38e62dd4f.zip
iio: temperature: mcp9600: Fix temperature reading for negative values
Temperature is stored as 16bit value in two's complement format. Current implementation ignores the sign bit. Make it aware of the sign bit by using sign_extend32. Fixes: 3f6b9598b6df ("iio: temperature: Add MCP9600 thermocouple EMF converter") Signed-off-by: Dimitri Fedrau <dima.fedrau@gmail.com> Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com> Tested-by: Andrew Hepp <andrew.hepp@ahepp.dev> Link: https://lore.kernel.org/r/20240424185913.1177127-1-dima.fedrau@gmail.com Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
-rw-r--r--drivers/iio/temperature/mcp9600.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/iio/temperature/mcp9600.c b/drivers/iio/temperature/mcp9600.c
index 46845804292b..7a3eef5d5e75 100644
--- a/drivers/iio/temperature/mcp9600.c
+++ b/drivers/iio/temperature/mcp9600.c
@@ -52,7 +52,8 @@ static int mcp9600_read(struct mcp9600_data *data,
if (ret < 0)
return ret;
- *val = ret;
+
+ *val = sign_extend32(ret, 15);
return 0;
}