staging: comedi: das6402: convert driver to use the comedi_8254 module

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

Remove the unnecessary programming of timer 0. The private data 'count'
value is never set by the driver and the timer is reset to MODE0 when
the timers are initialized during the attach of the driver.

Remove the unnecessart convert_src check in the (*do_cmdtest). The only
valid convert_src is TRIG_TIMER.
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

@@ -329,6 +329,7 @@ config COMEDI_DAS1800
 
 config COMEDI_DAS6402
 	tristate "DAS6402 and compatible ISA card support"
+	select COMEDI_8254
 	---help---
 	  Enable support for DAS6402 and compatible ISA cards
 	  Computerboards, Keithley Metrabyte DAS6402 and compatibles

drivers/staging/comedi/drivers/das6402.c

@@ -35,8 +35,9 @@
 #include <linux/interrupt.h>
 
 #include "../comedidev.h"
+
 #include "comedi_fc.h"
-#include "8253.h"
+#include "comedi_8254.h"
 
 /*
  * Register I/O map
@@ -138,11 +139,6 @@ static struct das6402_boardinfo das6402_boards[] = {
 
 struct das6402_private {
 	unsigned int irq;
-
-	unsigned int count;
-	unsigned int divider1;
-	unsigned int divider2;
-
 	unsigned int ao_range;
 };
 
@@ -172,27 +168,6 @@ static void das6402_ai_clear_eoc(struct comedi_device *dev)
 	outb(DAS6402_STATUS_W_CLRINT, dev->iobase + DAS6402_STATUS_REG);
 }
 
-static void das6402_enable_counter(struct comedi_device *dev, bool load)
-{
-	struct das6402_private *devpriv = dev->private;
-	unsigned long timer_iobase = dev->iobase + DAS6402_TIMER_BASE;
-
-	if (load) {
-		i8254_set_mode(timer_iobase, 0, 0, I8254_MODE0 | I8254_BINARY);
-		i8254_set_mode(timer_iobase, 0, 1, I8254_MODE2 | I8254_BINARY);
-		i8254_set_mode(timer_iobase, 0, 2, I8254_MODE2 | I8254_BINARY);
-
-		i8254_write(timer_iobase, 0, 0, devpriv->count);
-		i8254_write(timer_iobase, 0, 1, devpriv->divider1);
-		i8254_write(timer_iobase, 0, 2, devpriv->divider2);
-
-	} else {
-		i8254_set_mode(timer_iobase, 0, 0, I8254_MODE0 | I8254_BINARY);
-		i8254_set_mode(timer_iobase, 0, 1, I8254_MODE0 | I8254_BINARY);
-		i8254_set_mode(timer_iobase, 0, 2, I8254_MODE0 | I8254_BINARY);
-	}
-}
-
 static unsigned int das6402_ai_read_sample(struct comedi_device *dev,
 					   struct comedi_subdevice *s)
 {
@@ -267,7 +242,8 @@ static int das6402_ai_cmd(struct comedi_device *dev,
 	outw(DAS6402_AI_MUX_HI(chan_hi) | DAS6402_AI_MUX_LO(chan_lo),
 	     dev->iobase + DAS6402_AI_MUX_REG);
 
-	das6402_enable_counter(dev, true);
+	comedi_8254_update_divisors(dev->pacer);
+	comedi_8254_pacer_enable(dev->pacer, 1, 2, true);
 
 	/* enable interrupt and pacer trigger */
 	outb(DAS6402_CTRL_INTE |
@@ -322,7 +298,6 @@ static int das6402_ai_cmdtest(struct comedi_device *dev,
 			      struct comedi_subdevice *s,
 			      struct comedi_cmd *cmd)
 {
-	struct das6402_private *devpriv = dev->private;
 	int err = 0;
 	unsigned int arg;
 
@@ -364,14 +339,9 @@ static int das6402_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_10MHZ,
-					  &devpriv->divider1,
-					  &devpriv->divider2,
-					  &arg, cmd->flags);
-		err |= cfc_check_trigger_arg_is(&cmd->convert_arg, arg);
-	}
+	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);
 
 	if (err)
 		return 4;
@@ -581,8 +551,6 @@ static void das6402_reset(struct comedi_device *dev)
 	outw(0, dev->iobase + DAS6402_AO_DATA_REG(0));
 	inw(dev->iobase + DAS6402_AO_LSB_REG(0));
 
-	das6402_enable_counter(dev, false);
-
 	/* set all digital outputs low */
 	outb(0, dev->iobase + DAS6402_DI_DO_REG);
 
@@ -631,6 +599,11 @@ static int das6402_attach(struct comedi_device *dev,
 		}
 	}
 
+	dev->pacer = comedi_8254_init(dev->iobase + DAS6402_TIMER_BASE,
+				      I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
+	if (!dev->pacer)
+		return -ENOMEM;
+
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)
 		return ret;