From ad774285beee4e6cf71b5a87e2114dc04ba9ce41 Mon Sep 17 00:00:00 2001 From: Jeremy Fertic Date: Sat, 22 Dec 2018 21:57:42 -0700 Subject: [PATCH] staging: iio: adt7316: fix the dac read calculation commit 45130fb030aec26ac28b4bb23344901df3ec3b7f upstream. The calculation of the current dac value is using the wrong bits of the dac lsb register. Create two macros to shift the lsb register value into lsb position, depending on whether the dac is 10 or 12 bit. Initialize data to 0 so, with an 8 bit dac, the msb register value can be bitwise ORed with data. Fixes: 35f6b6b86ede ("staging: iio: new ADT7316/7/8 and ADT7516/7/9 driver") Signed-off-by: Jeremy Fertic Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/staging/iio/addac/adt7316.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/staging/iio/addac/adt7316.c b/drivers/staging/iio/addac/adt7316.c index 4bf82e11f03e..43c318a68b66 100644 --- a/drivers/staging/iio/addac/adt7316.c +++ b/drivers/staging/iio/addac/adt7316.c @@ -47,6 +47,8 @@ #define ADT7516_MSB_AIN3 0xA #define ADT7516_MSB_AIN4 0xB #define ADT7316_DA_DATA_BASE 0x10 +#define ADT7316_DA_10_BIT_LSB_SHIFT 6 +#define ADT7316_DA_12_BIT_LSB_SHIFT 4 #define ADT7316_DA_MSB_DATA_REGS 4 #define ADT7316_LSB_DAC_A 0x10 #define ADT7316_MSB_DAC_A 0x11 @@ -1408,7 +1410,7 @@ static IIO_DEVICE_ATTR(ex_analog_temp_offset, 0644, static ssize_t adt7316_show_DAC(struct adt7316_chip_info *chip, int channel, char *buf) { - u16 data; + u16 data = 0; u8 msb, lsb, offset; int ret; @@ -1433,7 +1435,11 @@ static ssize_t adt7316_show_DAC(struct adt7316_chip_info *chip, if (ret) return -EIO; - data = (msb << offset) + (lsb & ((1 << offset) - 1)); + if (chip->dac_bits == 12) + data = lsb >> ADT7316_DA_12_BIT_LSB_SHIFT; + else if (chip->dac_bits == 10) + data = lsb >> ADT7316_DA_10_BIT_LSB_SHIFT; + data |= msb << offset; return sprintf(buf, "%d\n", data); } -- GitLab