staging: comedi: das16m1: convert driver to use the comedi_8254 module

This driver uses two 8254 timers. One to generate the analog input pacer clock and
one to count the number of samples. Convert it to use the comedi_8254 module to
provide support for the 8254 timers.

Use the comedi_device 'pacer' member for the 8254 timer used for analog input. This
data is freed automatically by the core during the detach of the driver.

Store the data for the 8254 timer used to count samples in the private data. This
data needs to be freed by the driver when it is detached.
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

@@ -263,6 +263,7 @@ config COMEDI_DAC02
 
 config COMEDI_DAS16M1
 	tristate "MeasurementComputing CIO-DAS16/M1DAS-16 ISA card support"
+	select COMEDI_8254
 	select COMEDI_8255
 	---help---
 	  Enable support for Measurement Computing CIO-DAS16/M1 ISA cards.

drivers/staging/comedi/drivers/das16m1.c

@@ -53,11 +53,12 @@ irq can be omitted, although the cmd interface will not work without it.
 */
 
 #include <linux/module.h>
+#include <linux/slab.h>
 #include <linux/interrupt.h>
 #include "../comedidev.h"
 
 #include "8255.h"
-#include "8253.h"
+#include "comedi_8254.h"
 #include "comedi_fc.h"
 
 #define DAS16M1_SIZE2 8
@@ -103,8 +104,6 @@ irq can be omitted, although the cmd interface will not work without it.
 #define   Q_RANGE(x)             (((x) & 0xf) << 4)
 #define   UNIPOLAR               0x40
 #define DAS16M1_8254_FIRST             0x8
-#define DAS16M1_8254_FIRST_CNTRL       0xb
-#define   TOTAL_CLEAR                    0x30
 #define DAS16M1_8254_SECOND            0xc
 #define DAS16M1_82C55                  0x400
 #define DAS16M1_8254_THIRD             0x404
@@ -124,6 +123,7 @@ static const struct comedi_lrange range_das16m1 = {
 };
 
 struct das16m1_private_struct {
+	struct comedi_8254 *counter;
 	unsigned int control_state;
 	unsigned int adc_count;	/*  number of samples completed */
 	/* initial value in lower half of hardware conversion counter,
@@ -131,8 +131,6 @@ struct das16m1_private_struct {
 	 * counter yet (loaded by first sample conversion) */
 	u16 initial_hw_count;
 	unsigned short ai_buffer[FIFO_SIZE];
-	unsigned int divisor1;	/*  divides master clock to obtain conversion speed */
-	unsigned int divisor2;	/*  divides master clock to obtain conversion speed */
 	unsigned long extra_iobase;
 };
 
@@ -180,9 +178,7 @@ static int das16m1_ai_check_chanlist(struct comedi_device *dev,
 static int das16m1_cmd_test(struct comedi_device *dev,
 			    struct comedi_subdevice *s, struct comedi_cmd *cmd)
 {
-	struct das16m1_private_struct *devpriv = dev->private;
 	int err = 0;
-	unsigned int arg;
 
 	/* Step 1 : check if triggers are trivially valid */
 
@@ -229,11 +225,9 @@ static int das16m1_cmd_test(struct comedi_device *dev,
 	/* step 4: fix up arguments */
 
 	if (cmd->convert_src == TRIG_TIMER) {
-		arg = cmd->convert_arg;
-		i8253_cascade_ns_to_timer(I8254_OSC_BASE_10MHZ,
-					  &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);
 	}
 
@@ -250,25 +244,12 @@ static int das16m1_cmd_test(struct comedi_device *dev,
 	return 0;
 }
 
-static void das16m1_set_pacer(struct comedi_device *dev)
-{
-	struct das16m1_private_struct *devpriv = dev->private;
-	unsigned long timer_base = dev->iobase + DAS16M1_8254_SECOND;
-
-	i8254_set_mode(timer_base, 0, 1, I8254_MODE2 | I8254_BINARY);
-	i8254_set_mode(timer_base, 0, 2, I8254_MODE2 | I8254_BINARY);
-
-	i8254_write(timer_base, 0, 1, devpriv->divisor1);
-	i8254_write(timer_base, 0, 2, devpriv->divisor2);
-}
-
 static int das16m1_cmd_exec(struct comedi_device *dev,
 			    struct comedi_subdevice *s)
 {
 	struct das16m1_private_struct *devpriv = dev->private;
 	struct comedi_async *async = s->async;
 	struct comedi_cmd *cmd = &async->cmd;
-	unsigned long timer_base = dev->iobase + DAS16M1_8254_FIRST;
 	unsigned int byte, i;
 
 	/* disable interrupts and internal pacer */
@@ -277,14 +258,21 @@ static int das16m1_cmd_exec(struct comedi_device *dev,
 
 	/*  set software count */
 	devpriv->adc_count = 0;
-	/* Initialize lower half of hardware counter, used to determine how
+
+	/*
+	 * Initialize lower half of hardware counter, used to determine how
 	 * many samples are in fifo.  Value doesn't actually load into counter
-	 * until counter's next clock (the next a/d conversion) */
-	i8254_set_mode(timer_base, 0, 1, I8254_MODE2 | I8254_BINARY);
-	i8254_write(timer_base, 0, 1, 0);
-	/* remember current reading of counter so we know when counter has
-	 * actually been loaded */
-	devpriv->initial_hw_count = i8254_read(timer_base, 0, 1);
+	 * until counter's next clock (the next a/d conversion).
+	 */
+	comedi_8254_set_mode(devpriv->counter, 1, I8254_MODE2 | I8254_BINARY);
+	comedi_8254_write(devpriv->counter, 1, 0);
+
+	/*
+	 * Remember current reading of counter so we know when counter has
+	 * actually been loaded.
+	 */
+	devpriv->initial_hw_count = comedi_8254_read(devpriv->counter, 1);
+
 	/* setup channel/gain queue */
 	for (i = 0; i < cmd->chanlist_len; i++) {
 		outb(i, dev->iobase + DAS16M1_QUEUE_ADDR);
@@ -297,7 +285,8 @@ static int das16m1_cmd_exec(struct comedi_device *dev,
 	/* enable interrupts and set internal pacer counter mode and counts */
 	devpriv->control_state &= ~PACER_MASK;
 	if (cmd->convert_src == TRIG_TIMER) {
-		das16m1_set_pacer(dev);
+		comedi_8254_update_divisors(dev->pacer);
+		comedi_8254_pacer_enable(dev->pacer, 1, 2, true);
 		devpriv->control_state |= INT_PACER;
 	} else {	/* TRIG_EXT */
 		devpriv->control_state |= EXT_PACER;
@@ -418,7 +407,7 @@ static void das16m1_handler(struct comedi_device *dev, unsigned int status)
 	cmd = &async->cmd;
 
 	/* figure out how many samples are in fifo */
-	hw_counter = i8254_read(dev->iobase + DAS16M1_8254_FIRST, 0, 1);
+	hw_counter = comedi_8254_read(devpriv->counter, 1);
 	/* make sure hardware counter reading is not bogus due to initial value
 	 * not having been loaded yet */
 	if (devpriv->adc_count == 0 && hw_counter == devpriv->initial_hw_count) {
@@ -563,6 +552,16 @@ static int das16m1_attach(struct comedi_device *dev,
 			dev->irq = it->options[1];
 	}
 
+	dev->pacer = comedi_8254_init(dev->iobase + DAS16M1_8254_SECOND,
+				      I8254_OSC_BASE_10MHZ, I8254_IO8, 0);
+	if (!dev->pacer)
+		return -ENOMEM;
+
+	devpriv->counter = comedi_8254_init(dev->iobase + DAS16M1_8254_FIRST,
+					    0, I8254_IO8, 0);
+	if (!devpriv->counter)
+		return -ENOMEM;
+
 	ret = comedi_alloc_subdevices(dev, 4);
 	if (ret)
 		return ret;
@@ -609,9 +608,6 @@ static int das16m1_attach(struct comedi_device *dev,
 	if (ret)
 		return ret;
 
-	/*  disable upper half of hardware conversion counter so it doesn't mess with us */
-	outb(TOTAL_CLEAR, dev->iobase + DAS16M1_8254_FIRST_CNTRL);
-
 	/*  initialize digital output lines */
 	outb(0, dev->iobase + DAS16M1_DIO);
 
@@ -626,8 +622,11 @@ static void das16m1_detach(struct comedi_device *dev)
 {
 	struct das16m1_private_struct *devpriv = dev->private;
 
-	if (devpriv && devpriv->extra_iobase)
+	if (devpriv) {
+		if (devpriv->extra_iobase)
 			release_region(devpriv->extra_iobase, DAS16M1_SIZE2);
+		kfree(devpriv->counter);
+	}
 	comedi_legacy_detach(dev);
 }