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Commit 750bca65 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: das1800: add analog output readback 



Use the core provided readback support to allow reading back the last
value written to the analog output channels.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a5405cfa

drivers/staging/comedi/drivers/das1800.c

+9 −8
Original line number Diff line number Diff line
@@ -91,7 +91,6 @@ Unipolar and bipolar ranges cannot be mixed in the channel/gain list. 
TODO:

	Make it automatically allocate irq and dma channels if they are not specified

	Add support for analog out on 'ao' cards

	read insn for analog out

*/



#include <linux/module.h>
@@ -341,8 +340,6 @@ struct das1800_private { 
	int dma_bits;

	uint16_t *fifo_buf;	/* bounce buffer for analog input FIFO */

	unsigned long iobase2;	/* secondary io address used for analog out on 'ao' boards */

	unsigned short ao_update_bits;	/* remembers the last write to the

					 * 'update' dac */

	bool ai_is_unipolar;

};
@@ -1017,7 +1014,6 @@ static int das1800_ao_insn_write(struct comedi_device *dev, 
				 struct comedi_insn *insn,

				 unsigned int *data)

{

	struct das1800_private *devpriv = dev->private;

	unsigned int chan = CR_CHAN(insn->chanspec);

	unsigned int update_chan = s->n_chan - 1;

	unsigned long flags;
@@ -1029,9 +1025,9 @@ static int das1800_ao_insn_write(struct comedi_device *dev, 
	for (i = 0; i < insn->n; i++) {

		unsigned int val = data[i];



		s->readback[chan] = val;



		val = comedi_offset_munge(s, val);

		if (chan == update_chan)

			devpriv->ao_update_bits = val;



		/* load this channel (and update if it's the last channel) */

		outb(DAC(chan), dev->iobase + DAS1800_SELECT);
@@ -1039,9 +1035,10 @@ static int das1800_ao_insn_write(struct comedi_device *dev, 


		/* update all channels */

		if (chan != update_chan) {

			val = comedi_offset_munge(s, s->readback[update_chan]);



			outb(DAC(update_chan), dev->iobase + DAS1800_SELECT);

			outw(devpriv->ao_update_bits,

			     dev->iobase + DAS1800_DAC);

			outw(val, dev->iobase + DAS1800_DAC);

		}

	}

	spin_unlock_irqrestore(&dev->spinlock, flags);
@@ -1318,6 +1315,10 @@ static int das1800_attach(struct comedi_device *dev, 
		s->range_table	= &range_bipolar10;

		s->insn_write	= das1800_ao_insn_write;



		ret = comedi_alloc_subdev_readback(s);

		if (ret)

			return ret;



		/* initialize all channels to 0V */

		for (i = 0; i < s->n_chan; i++) {

			outb(DAC(i), dev->iobase + DAS1800_SELECT);