staging: comedi: pcl818: 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 pcl818_ai_cmd() or when the card is initialy reset by pcl818_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

@@ -191,6 +191,7 @@ config COMEDI_PCL816
 config COMEDI_PCL818
 	tristate "Advantech PCL-718 and PCL-818 ISA card support"
 	select COMEDI_ISADMA if ISA_DMA_API
+	select COMEDI_8254
 	---help---
 	  Enable support for Advantech PCL-818 ISA cards
 	  PCL-818L, PCL-818H, PCL-818HD, PCL-818HG, PCL-818 and PCL-718

drivers/staging/comedi/drivers/pcl818.c

@@ -101,7 +101,7 @@
 
 #include "comedi_isadma.h"
 #include "comedi_fc.h"
-#include "8253.h"
+#include "comedi_8254.h"
 
 /* boards constants */
 
@@ -299,33 +299,15 @@ struct pcl818_private {
 	struct comedi_isadma *dma;
 	/*  manimal allowed delay between samples (in us) for actual card */
 	unsigned int ns_min;
-	int i8253_osc_base;	/*  1/frequency of on board oscilator in ns */
 	/*  MUX setting for actual AI operations */
 	unsigned int act_chanlist[16];
 	unsigned int act_chanlist_len;	/*  how long is actual MUX list */
 	unsigned int act_chanlist_pos;	/*  actual position in MUX list */
-	unsigned int divisor1;
-	unsigned int divisor2;
 	unsigned int usefifo:1;
 	unsigned int ai_cmd_running:1;
 	unsigned int ai_cmd_canceled:1;
 };
 
-static void pcl818_start_pacer(struct comedi_device *dev, bool load_counters)
-{
-	struct pcl818_private *devpriv = dev->private;
-	unsigned long timer_base = dev->iobase + PCL818_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_counters) {
-		i8254_write(timer_base, 0, 2, devpriv->divisor2);
-		i8254_write(timer_base, 0, 1, devpriv->divisor1);
-	}
-}
-
 static void pcl818_ai_setup_dma(struct comedi_device *dev,
 				struct comedi_subdevice *s,
 				unsigned int unread_samples)
@@ -663,9 +645,7 @@ static int ai_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s,
 		      struct comedi_cmd *cmd)
 {
 	const struct pcl818_board *board = dev->board_ptr;
-	struct pcl818_private *devpriv = dev->private;
 	int err = 0;
-	unsigned int arg;
 
 	/* Step 1 : check if triggers are trivially valid */
 
@@ -712,11 +692,9 @@ static int ai_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s,
 	/* step 4: fix up any arguments */
 
 	if (cmd->convert_src == TRIG_TIMER) {
-		arg = cmd->convert_arg;
-		i8253_cascade_ns_to_timer(devpriv->i8253_osc_base,
-					  &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);
 	}
 
@@ -746,8 +724,6 @@ static int pcl818_ai_cmd(struct comedi_device *dev,
 	if (devpriv->ai_cmd_running)
 		return -EBUSY;
 
-	pcl818_start_pacer(dev, false);
-
 	seglen = check_channel_list(dev, s, cmd->chanlist, cmd->chanlist_len);
 	if (seglen < 1)
 		return -EINVAL;
@@ -779,8 +755,10 @@ static int pcl818_ai_cmd(struct comedi_device *dev,
 	}
 	outb(ctrl, dev->iobase + PCL818_CTRL_REG);
 
-	if (cmd->convert_src == TRIG_TIMER)
-		pcl818_start_pacer(dev, true);
+	if (cmd->convert_src == TRIG_TIMER) {
+		comedi_8254_update_divisors(dev->pacer);
+		comedi_8254_pacer_enable(dev->pacer, 1, 2, true);
+	}
 
 	return 0;
 }
@@ -812,7 +790,7 @@ static int pcl818_ai_cancel(struct comedi_device *dev,
 	}
 
 	outb(PCL818_CTRL_DISABLE_TRIG, dev->iobase + PCL818_CTRL_REG);
-	pcl818_start_pacer(dev, false);
+	comedi_8254_pacer_enable(dev->pacer, 1, 2, false);
 	pcl818_ai_clear_eoc(dev);
 
 	if (devpriv->usefifo) {	/*  FIFO shutdown */
@@ -906,7 +884,6 @@ static int pcl818_do_insn_bits(struct comedi_device *dev,
 static void pcl818_reset(struct comedi_device *dev)
 {
 	const struct pcl818_board *board = dev->board_ptr;
-	unsigned long timer_base = dev->iobase + PCL818_TIMER_BASE;
 	unsigned int chan;
 
 	/* flush and disable the FIFO */
@@ -924,9 +901,6 @@ static void pcl818_reset(struct comedi_device *dev)
 
 	/* stop pacer */
 	outb(PCL818_CNTENABLE_PACER_ENA, dev->iobase + PCL818_CNTENABLE_REG);
-	i8254_set_mode(timer_base, 0, 2, I8254_MODE0 | I8254_BINARY);
-	i8254_set_mode(timer_base, 0, 1, I8254_MODE0 | I8254_BINARY);
-	i8254_set_mode(timer_base, 0, 0, I8254_MODE0 | I8254_BINARY);
 
 	/* set analog output channels to 0V */
 	for (chan = 0; chan < board->n_aochan; chan++) {
@@ -1016,6 +990,7 @@ static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	const struct pcl818_board *board = dev->board_ptr;
 	struct pcl818_private *devpriv;
 	struct comedi_subdevice *s;
+	unsigned int osc_base;
 	int ret;
 
 	devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
@@ -1043,6 +1018,25 @@ static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	if (dev->irq && board->has_dma)
 		pcl818_alloc_dma(dev, it->options[2]);
 
+	/* use 1MHz or 10MHz oscilator */
+	if ((it->options[3] == 0) || (it->options[3] == 10))
+		osc_base = I8254_OSC_BASE_10MHZ;
+	else
+		osc_base = I8254_OSC_BASE_1MHZ;
+
+	dev->pacer = comedi_8254_init(dev->iobase + PCL818_TIMER_BASE,
+				      osc_base, I8254_IO8, 0);
+	if (!dev->pacer)
+		return -ENOMEM;
+
+	/* max sampling speed */
+	devpriv->ns_min = board->ns_min;
+	if (!board->is_818) {
+		/* extended PCL718 to 100kHz DAC */
+		if ((it->options[6] == 1) || (it->options[6] == 100))
+			devpriv->ns_min = 10000;
+	}
+
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)
 		return ret;
@@ -1117,22 +1111,6 @@ static int pcl818_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	s->range_table	= &range_digital;
 	s->insn_bits	= pcl818_do_insn_bits;
 
-	/* select 1/10MHz oscilator */
-	if ((it->options[3] == 0) || (it->options[3] == 10))
-		devpriv->i8253_osc_base = I8254_OSC_BASE_10MHZ;
-	else
-		devpriv->i8253_osc_base = I8254_OSC_BASE_1MHZ;
-
-	/* max sampling speed */
-	devpriv->ns_min = board->ns_min;
-
-	if (!board->is_818) {
-		if ((it->options[6] == 1) || (it->options[6] == 100)) {
-			/* extended PCL718 to 100kHz DAC */
-			devpriv->ns_min = 10000;
-		}
-	}
-
 	pcl818_reset(dev);
 
 	return 0;