From 1764eff7d5d644310b87d7040c83fe5208c155f7 Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Tue, 3 Jul 2012 11:21:27 +0200 Subject: [PATCH] staging iio adt7410: fix 13bit mode The driver assumes that in 13bit mode the 16bit value has to be shifted to the right by 3 bits. This is not true, in both 16bit and 13bit mode the MSB is at the same position. Currently the driver returns a temperature of 194 degrees Celsius in 13bit mode and 24 degrees Celsius in 16bit mode. Fix this by using the same algorithm for 16bit and 13bit mode and by just masking out the lower three bits in 13bit mode. Signed-off-by: Sascha Hauer Acked-by: Sonic Zhang Signed-off-by: Jonathan Cameron --- drivers/staging/iio/adc/adt7410.c | 29 ++++++++++------------------- 1 file changed, 10 insertions(+), 19 deletions(-) diff --git a/drivers/staging/iio/adc/adt7410.c b/drivers/staging/iio/adc/adt7410.c index 9025161dfe0e..f87992cd1acc 100644 --- a/drivers/staging/iio/adc/adt7410.c +++ b/drivers/staging/iio/adc/adt7410.c @@ -293,26 +293,17 @@ static ssize_t adt7410_convert_temperature(struct adt7410_chip_info *chip, { char sign = ' '; - if (chip->config & ADT7410_RESOLUTION) { - if (data & ADT7410_T16_VALUE_SIGN) { - /* convert supplement to positive value */ - data = (u16)((ADT7410_T16_VALUE_SIGN << 1) - (u32)data); - sign = '-'; - } - return sprintf(buf, "%c%d.%.7d\n", sign, - (data >> ADT7410_T16_VALUE_FLOAT_OFFSET), - (data & ADT7410_T16_VALUE_FLOAT_MASK) * 78125); - } else { - if (data & ADT7410_T13_VALUE_SIGN) { - /* convert supplement to positive value */ - data >>= ADT7410_T13_VALUE_OFFSET; - data = (ADT7410_T13_VALUE_SIGN << 1) - data; - sign = '-'; - } - return sprintf(buf, "%c%d.%.4d\n", sign, - (data >> ADT7410_T13_VALUE_FLOAT_OFFSET), - (data & ADT7410_T13_VALUE_FLOAT_MASK) * 625); + if (!(chip->config & ADT7410_RESOLUTION)) + data &= ~0x7; + + if (data & ADT7410_T16_VALUE_SIGN) { + /* convert supplement to positive value */ + data = (u16)((ADT7410_T16_VALUE_SIGN << 1) - (u32)data); + sign = '-'; } + return sprintf(buf, "%c%d.%.7d\n", sign, + (data >> ADT7410_T16_VALUE_FLOAT_OFFSET), + (data & ADT7410_T16_VALUE_FLOAT_MASK) * 78125); } static ssize_t adt7410_show_value(struct device *dev, -- 2.30.2