staging: comedi: pcl812: convert driver to use the comedi_8254 module

This driver uses an 8254 timer to generate the pacer clock used for analog
input data acquisition. Convert it to use the comedi_8254 module to provide
support for the 8254 timer.

Note that the pacer does not have to be stopped when starting a new async
command in pcl812_ai_cmd() or when the card is initialy reset by pcl812_reset().
The counters are all reset when the driver is initially attached and the
counters used by the pacer are stopped when a command is canceled.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/Kconfig

@@ -169,6 +169,7 @@ config COMEDI_PCL730
 config COMEDI_PCL812
 	tristate "Advantech PCL-812/813 and ADlink ACL-8112/8113/8113/8216"
 	select COMEDI_ISADMA if ISA_DMA_API
+	select COMEDI_8254
 	---help---
 	  Enable support for Advantech PCL-812/PG, PCL-813/B, ADLink
 	  ACL-8112DG/HG/PG, ACL-8113, ACL-8216, ICP DAS A-821PGH/PGL/PGL-NDA,

drivers/staging/comedi/drivers/pcl812.c

@@ -118,7 +118,7 @@
 
 #include "comedi_isadma.h"
 #include "comedi_fc.h"
-#include "8253.h"
+#include "comedi_8254.h"
 
 /* hardware types of the cards */
 #define boardPCL812PG	      0	/* and ACL-8112PG */
@@ -513,8 +513,6 @@ struct pcl812_private {
 	unsigned char mode_reg_int;	/*  there is stored INT number for some card */
 	unsigned int ai_poll_ptr;	/*  how many sampes transfer poll */
 	unsigned int max_812_ai_mode0_rangewait;	/*  setling time for gain */
-	unsigned int divisor1;
-	unsigned int divisor2;
 	unsigned int use_diff:1;
 	unsigned int use_mpc508:1;
 	unsigned int use_ext_trg:1;
@@ -522,21 +520,6 @@ struct pcl812_private {
 	unsigned int ai_eos:1;
 };
 
-static void pcl812_start_pacer(struct comedi_device *dev, bool load_timers)
-{
-	struct pcl812_private *devpriv = dev->private;
-	unsigned long timer_base = dev->iobase + PCL812_TIMER_BASE;
-
-	i8254_set_mode(timer_base, 0, 2, I8254_MODE2 | I8254_BINARY);
-	i8254_set_mode(timer_base, 0, 1, I8254_MODE2 | I8254_BINARY);
-	udelay(1);
-
-	if (load_timers) {
-		i8254_write(timer_base, 0, 2, devpriv->divisor2);
-		i8254_write(timer_base, 0, 1, devpriv->divisor1);
-	}
-}
-
 static void pcl812_ai_setup_dma(struct comedi_device *dev,
 				struct comedi_subdevice *s,
 				unsigned int unread_samples)
@@ -650,7 +633,6 @@ static int pcl812_ai_cmdtest(struct comedi_device *dev,
 	struct pcl812_private *devpriv = dev->private;
 	int err = 0;
 	unsigned int flags;
-	unsigned int arg;
 
 	/* Step 1 : check if triggers are trivially valid */
 
@@ -703,11 +685,9 @@ static int pcl812_ai_cmdtest(struct comedi_device *dev,
 	/* step 4: fix up any arguments */
 
 	if (cmd->convert_src == TRIG_TIMER) {
-		arg = cmd->convert_arg;
-		i8253_cascade_ns_to_timer(I8254_OSC_BASE_2MHZ,
-					  &devpriv->divisor1,
-					  &devpriv->divisor2,
-					  &arg, cmd->flags);
+		unsigned int arg = cmd->convert_arg;
+
+		comedi_8254_cascade_ns_to_timer(dev->pacer, &arg, cmd->flags);
 		err |= cfc_check_trigger_arg_is(&cmd->convert_arg, arg);
 	}
 
@@ -725,8 +705,6 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 	unsigned int ctrl = 0;
 	unsigned int i;
 
-	pcl812_start_pacer(dev, false);
-
 	pcl812_ai_set_chan_range(dev, cmd->chanlist[0], 1);
 
 	if (dma) {	/*  check if we can use DMA transfer */
@@ -760,7 +738,8 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 
 	switch (cmd->convert_src) {
 	case TRIG_TIMER:
-		pcl812_start_pacer(dev, true);
+		comedi_8254_update_divisors(dev->pacer);
+		comedi_8254_pacer_enable(dev->pacer, 1, 2, true);
 		break;
 	}
 
@@ -918,7 +897,7 @@ static int pcl812_ai_cancel(struct comedi_device *dev,
 
 	outb(devpriv->mode_reg_int | PCL812_CTRL_DISABLE_TRIG,
 	     dev->iobase + PCL812_CTRL_REG);
-	pcl812_start_pacer(dev, false);
+	comedi_8254_pacer_enable(dev->pacer, 1, 2, false);
 	pcl812_ai_clear_eoc(dev);
 	return 0;
 }
@@ -1010,10 +989,6 @@ static void pcl812_reset(struct comedi_device *dev)
 	     dev->iobase + PCL812_CTRL_REG);
 	pcl812_ai_clear_eoc(dev);
 
-	/* stop pacer */
-	if (board->IRQbits)
-		pcl812_start_pacer(dev, false);
-
 	/*
 	 * Invalidate last_ai_chanspec then set analog input to
 	 * known channel/range.
@@ -1162,12 +1137,20 @@ static int pcl812_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	if (ret)
 		return ret;
 
+	if (board->IRQbits) {
+		dev->pacer = comedi_8254_init(dev->iobase + PCL812_TIMER_BASE,
+					      I8254_OSC_BASE_2MHZ,
+					      I8254_IO8, 0);
+		if (!dev->pacer)
+			return -ENOMEM;
+
 		if ((1 << it->options[1]) & board->IRQbits) {
 			ret = request_irq(it->options[1], pcl812_interrupt, 0,
 					  dev->board_name, dev);
 			if (ret == 0)
 				dev->irq = it->options[1];
 		}
+	}
 
 	/* we need an IRQ to do DMA on channel 3 or 1 */
 	if (dev->irq && board->has_dma)