From 8fc9f652abd71fd53e17c3b2430e702e5a55fae2 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Mon, 17 Feb 2014 14:27:16 -0700 Subject: [PATCH] staging: comedi: pcl818: introduce pcl818_ai_get_sample() Introduce a helper function to read the 12-bit analog input data sample and optionally return the channel that the sample was for. The channel is only used in the interrupt routine to check for dropped samples. Signed-off-by: H Hartley Sweeten Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/pcl818.c | 30 +++++++++++++++++-------- 1 file changed, 21 insertions(+), 9 deletions(-) diff --git a/drivers/staging/comedi/drivers/pcl818.c b/drivers/staging/comedi/drivers/pcl818.c index 2b8e7e0d2c75..d5709edd6799 100644 --- a/drivers/staging/comedi/drivers/pcl818.c +++ b/drivers/staging/comedi/drivers/pcl818.c @@ -372,6 +372,21 @@ static int pcl818_ai_cancel(struct comedi_device *dev, static void start_pacer(struct comedi_device *dev, int mode, unsigned int divisor1, unsigned int divisor2); +static unsigned int pcl818_ai_get_sample(struct comedi_device *dev, + struct comedi_subdevice *s, + unsigned int *chan) +{ + unsigned int val; + + val = inb(dev->iobase + PCL818_AD_HI) << 8; + val |= inb(dev->iobase + PCL818_AD_LO); + + if (chan) + *chan = val & 0xf; + + return (val >> 4) & s->maxdata; +} + static int pcl818_ai_eoc(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, @@ -416,8 +431,7 @@ static int pcl818_ai_insn_read(struct comedi_device *dev, return ret; } - data[n] = ((inb(dev->iobase + PCL818_AD_HI) << 4) | - (inb(dev->iobase + PCL818_AD_LO) >> 4)); + data[n] = pcl818_ai_get_sample(dev, s, NULL); } return n; @@ -502,7 +516,7 @@ static irqreturn_t interrupt_pcl818_ai_mode13_int(int irq, void *d) struct comedi_device *dev = d; struct pcl818_private *devpriv = dev->private; struct comedi_subdevice *s = dev->read_subdev; - unsigned char low; + unsigned int chan; int timeout = 50; /* wait max 50us */ while (timeout--) { @@ -518,14 +532,13 @@ static irqreturn_t interrupt_pcl818_ai_mode13_int(int irq, void *d) return IRQ_HANDLED; conv_finish: - low = inb(dev->iobase + PCL818_AD_LO); - comedi_buf_put(s->async, ((inb(dev->iobase + PCL818_AD_HI) << 4) | (low >> 4))); /* get one sample */ + comedi_buf_put(s->async, pcl818_ai_get_sample(dev, s, &chan)); outb(0, dev->iobase + PCL818_CLRINT); /* clear INT request */ - if ((low & 0xf) != devpriv->act_chanlist[devpriv->act_chanlist_pos]) { /* dropout! */ + if (chan != devpriv->act_chanlist[devpriv->act_chanlist_pos]) { dev_dbg(dev->class_dev, "A/D mode1/3 IRQ - channel dropout %x!=%x !\n", - (low & 0xf), + chan, devpriv->act_chanlist[devpriv->act_chanlist_pos]); pcl818_ai_cancel(dev, s); s->async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR; @@ -1166,8 +1179,7 @@ static int pcl818_ai_cancel(struct comedi_device *dev, udelay(1); start_pacer(dev, -1, 0, 0); outb(0, dev->iobase + PCL818_AD_LO); - inb(dev->iobase + PCL818_AD_LO); - inb(dev->iobase + PCL818_AD_HI); + pcl818_ai_get_sample(dev, s, NULL); outb(0, dev->iobase + PCL818_CLRINT); /* clear INT request */ outb(0, dev->iobase + PCL818_CONTROL); /* Stop A/D */ if (devpriv->usefifo) { /* FIFO shutdown */ -- 2.30.2