Commit d8644e41 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
Browse files

staging: comedi: dt282x: use comedi_timeout() 



The wait_for() macro in this driver is a bit nasty. It effects control flow
which according to the CodingStyle is a _very_ bad idea.

The mux_busy() and ad_done() macros are also bad since they rely on a local
variable having a specific name.

Remove these macros and use comedi_timeout() to wait for the analog input
mux busy completion and end-of-conversion. Both of these are detected by
reading the same register and testing different bits. Pass the bits to test
as the 'context' to the callback function.

The dt282x_ai_cmd() function also checks for the mux busy completion. The
'insn' is not available here but passing NULL is safe because nothing
uses it.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 45b281e4

drivers/staging/comedi/drivers/dt282x.c

+42 −26
Original line number Diff line number Diff line
@@ -63,7 +63,6 @@ Notes: 


#include "comedi_fc.h"



#define DT2821_TIMEOUT		100	/* 500 us */

#define DT2821_SIZE 0x10



/*
@@ -248,27 +247,6 @@ struct dt282x_private { 
 *    Some useless abstractions

 */

#define chan_to_DAC(a)	((a)&1)

#define mux_busy() (inw(dev->iobase+DT2821_ADCSR)&DT2821_MUXBUSY)

#define ad_done() (inw(dev->iobase+DT2821_ADCSR)&DT2821_ADDONE)



/*

 *    danger! macro abuse... a is the expression to wait on, and b is

 *      the statement(s) to execute if it doesn't happen.

 */

#define wait_for(a, b)						\

	do {							\

		int _i;						\

		for (_i = 0; _i < DT2821_TIMEOUT; _i++) {	\

			if (a) {				\

				_i = 0;				\

				break;				\

			}					\

			udelay(5);				\

		}						\

		if (_i) {					\

			b					\

		}						\

	} while (0)



static int prep_ai_dma(struct comedi_device *dev, int chan, int size);

static int prep_ao_dma(struct comedi_device *dev, int chan, int size);
@@ -530,6 +508,29 @@ static void dt282x_load_changain(struct comedi_device *dev, int n, 
	outw(n - 1, dev->iobase + DT2821_CHANCSR);

}



static int dt282x_ai_timeout(struct comedi_device *dev,

			     struct comedi_subdevice *s,

			     struct comedi_insn *insn,

			     unsigned long context)

{

	unsigned int status;



	status = inw(dev->iobase + DT2821_ADCSR);

	switch (context) {

	case DT2821_MUXBUSY:

		if ((status & DT2821_MUXBUSY) == 0)

			return 0;

		break;

	case DT2821_ADDONE:

		if (status & DT2821_ADDONE)

			return 0;

		break;

	default:

		return -EINVAL;

	}

	return -EBUSY;

}



/*

 *    Performs a single A/D conversion.

 *      - Put channel/gain into channel-gain list
@@ -542,6 +543,7 @@ static int dt282x_ai_insn_read(struct comedi_device *dev, 
{

	const struct dt282x_board *board = comedi_board(dev);

	struct dt282x_private *devpriv = dev->private;

	int ret;

	int i;



	/* XXX should we really be enabling the ad clock here? */
@@ -551,13 +553,22 @@ static int dt282x_ai_insn_read(struct comedi_device *dev, 
	dt282x_load_changain(dev, 1, &insn->chanspec);



	outw(devpriv->supcsr | DT2821_PRLD, dev->iobase + DT2821_SUPCSR);

	wait_for(!mux_busy(), comedi_error(dev, "timeout\n"); return -ETIME;);

	ret = comedi_timeout(dev, s, insn, dt282x_ai_timeout, DT2821_MUXBUSY);

	if (ret) {

		comedi_error(dev, "timeout\n");

		return ret;

	}



	for (i = 0; i < insn->n; i++) {

		outw(devpriv->supcsr | DT2821_STRIG,

			dev->iobase + DT2821_SUPCSR);

		wait_for(ad_done(), comedi_error(dev, "timeout\n");

			 return -ETIME;);



		ret = comedi_timeout(dev, s, insn, dt282x_ai_timeout,

				     DT2821_ADDONE);

		if (ret) {

			comedi_error(dev, "timeout\n");

			return ret;

		}



		data[i] =

		    inw(dev->iobase +
@@ -646,6 +657,7 @@ static int dt282x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 
	struct dt282x_private *devpriv = dev->private;

	struct comedi_cmd *cmd = &s->async->cmd;

	int timer;

	int ret;



	if (devpriv->usedma == 0) {

		comedi_error(dev,
@@ -691,7 +703,11 @@ static int dt282x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s) 
	outw(devpriv->adcsr, dev->iobase + DT2821_ADCSR);



	outw(devpriv->supcsr | DT2821_PRLD, dev->iobase + DT2821_SUPCSR);

	wait_for(!mux_busy(), comedi_error(dev, "timeout\n"); return -ETIME;);

	ret = comedi_timeout(dev, s, NULL, dt282x_ai_timeout, DT2821_MUXBUSY);

	if (ret) {

		comedi_error(dev, "timeout\n");

		return ret;

	}



	if (cmd->scan_begin_src == TRIG_FOLLOW) {

		outw(devpriv->supcsr | DT2821_STRIG,

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