From 827dca3129708a8465bde90c86c2e3c38e62dd4f Mon Sep 17 00:00:00 2001 From: Dimitri Fedrau Date: Wed, 24 Apr 2024 20:59:10 +0200 Subject: [PATCH] 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 Reviewed-by: Marcelo Schmitt Tested-by: Andrew Hepp Link: https://lore.kernel.org/r/20240424185913.1177127-1-dima.fedrau@gmail.com Cc: Signed-off-by: Jonathan Cameron --- drivers/iio/temperature/mcp9600.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) 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; } -- 2.25.1