From 7022781c460290687b374dab1c230c06091bba10 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Wed, 5 Aug 2015 10:45:19 -0700 Subject: [PATCH] staging: comedi: me4000: introduce me4000_ai_get_sample() The hardware returns two's complement values for the analog input samples. These need to be converted to the unsigned binary format that the comedi core expects. Introduce a helper function to handle this. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/me4000.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/staging/comedi/drivers/me4000.c b/drivers/staging/comedi/drivers/me4000.c index b17183dee7fb..3974f59c0478 100644 --- a/drivers/staging/comedi/drivers/me4000.c +++ b/drivers/staging/comedi/drivers/me4000.c @@ -445,6 +445,16 @@ static void me4000_reset(struct comedi_device *dev) outl(0x1, dev->iobase + ME4000_DIO_CTRL_REG); } +static unsigned int me4000_ai_get_sample(struct comedi_device *dev, + struct comedi_subdevice *s) +{ + unsigned int val; + + /* read two's complement value and munge to offset binary */ + val = inl(dev->iobase + ME4000_AI_DATA_REG); + return comedi_offset_munge(s, val); +} + static int me4000_ai_eoc(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, @@ -515,8 +525,7 @@ static int me4000_ai_insn_read(struct comedi_device *dev, if (ret) break; - /* read two's complement value and munge to offset binary */ - val = inl(dev->iobase + ME4000_AI_DATA_REG); + val = me4000_ai_get_sample(dev, s); data[i] = comedi_offset_munge(s, val); } @@ -953,10 +962,7 @@ static irqreturn_t me4000_ai_isr(int irq, void *dev_id) } for (i = 0; i < c; i++) { - /* Read value from data fifo */ - lval = inl(dev->iobase + ME4000_AI_DATA_REG) & 0xFFFF; - lval ^= 0x8000; - + lval = me4000_ai_get_sample(dev, s); if (!comedi_buf_write_samples(s, &lval, 1)) break; } @@ -976,10 +982,7 @@ static irqreturn_t me4000_ai_isr(int irq, void *dev_id) /* Poll data until fifo empty */ while (inl(dev->iobase + ME4000_AI_STATUS_REG) & ME4000_AI_STATUS_EF_DATA) { - /* Read value from data fifo */ - lval = inl(dev->iobase + ME4000_AI_DATA_REG) & 0xFFFF; - lval ^= 0x8000; - + lval = me4000_ai_get_sample(dev, s); if (!comedi_buf_write_samples(s, &lval, 1)) break; } -- 2.39.5