From: H Hartley Sweeten Date: Tue, 6 Oct 2015 18:11:11 +0000 (-0700) Subject: staging: comedi: mf6x4: A/D converter uses 2's complement coding X-Git-Tag: KARO-TX6UL-2015-11-03~34^2~868 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=597063341936a3ccddb30783781d474d7e7d70cd;p=karo-tx-linux.git staging: comedi: mf6x4: A/D converter uses 2's complement coding According to the user's manual, the A/D converter uses 2's complement coding. Use the comedi_offset_munge() helper to convert the data to the offset binary format used by comedi. Signed-off-by: H Hartley Sweeten drivers/staging/comedi/drivers/mf6x4.c | 5 ++--- Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/comedi/drivers/mf6x4.c b/drivers/staging/comedi/drivers/mf6x4.c index ff4ba15a23f0..1e4f08058723 100644 --- a/drivers/staging/comedi/drivers/mf6x4.c +++ b/drivers/staging/comedi/drivers/mf6x4.c @@ -38,7 +38,7 @@ #define MF6X4_GPIOC_DACEN BIT(26) /* BAR1 registers */ -#define MF6X4_ADDATA_R 0x00 +#define MF6X4_ADDATA_REG 0x00 #define MF6X4_ADCTRL_REG 0x00 #define MF6X4_ADCTRL_CHAN(x) BIT(chan) #define MF6X4_DIN_R 0x10 @@ -134,9 +134,9 @@ static int mf6x4_ai_insn_read(struct comedi_device *dev, unsigned int *data) { unsigned int chan = CR_CHAN(insn->chanspec); + unsigned int d; int ret; int i; - int d; /* Set the ADC channel number in the scan list */ iowrite16(MF6X4_ADCTRL_CHAN(chan), dev->mmio + MF6X4_ADCTRL_REG); @@ -150,9 +150,10 @@ static int mf6x4_ai_insn_read(struct comedi_device *dev, return ret; /* Read the actual value */ - d = ioread16(dev->mmio + MF6X4_ADDATA_R); + d = ioread16(dev->mmio + MF6X4_ADDATA_REG); d &= s->maxdata; - data[i] = d; + /* munge the 2's complement data to offset binary */ + data[i] = comedi_offset_munge(s, d); } iowrite16(0x0, dev->mmio + MF6X4_ADCTRL_REG);