Commit c62f5032 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
Browse files

comedi: comedi_8254: Use a call-back function for register access 



Rework the comedi_8254 module to use a call-back function for register
access.  This will make it easier to isolate the parts that will depend
on the `CONFIG_HAS_IOPORT` macro being defined and also allows the
possibility of supplying an external callback function during
initialization by a variant of the `comedi_8254_init()` and
`comedi_8254_mm_init()` functions, although that has not been
implemented yet.

The `struct comedi_8254` members have been changed to use a pointer to a
callback function and a context of type `unsigned long`.  The
`comedi_8254_init()` and `comedi_8254_mm_init()` functions use an
internal callback function and set the context to the base address of
the registers (for `comedi_8254_mm_init()` that involves converting a
`void __iomem *` to `unsigned long`).

A minor change to `dio200_subdev_8254_offset()` in the
amplc_dio200_common module has been made due to the changes in `struct
comedi_8254`.

Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20230913170712.111719-3-abbotti@mev.co.uk


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7b79e3d2

drivers/comedi/drivers/amplc_dio200_common.c

+2 −2
Original line number Diff line number Diff line
@@ -149,9 +149,9 @@ static unsigned int dio200_subdev_8254_offset(struct comedi_device *dev, 


	/* get the offset that was passed to comedi_8254_*_init() */

	if (dev->mmio)

		offset = i8254->mmio - dev->mmio;

		offset = (void __iomem *)i8254->context - dev->mmio;

	else

		offset = i8254->iobase - dev->iobase;

		offset = i8254->context - dev->iobase;



	/* remove the shift that was added for PCIe boards */

	if (board->is_pcie)

drivers/comedi/drivers/comedi_8254.c

+124 −53
Original line number Diff line number Diff line
@@ -119,63 +119,101 @@ 
#include <linux/comedi/comedidev.h>

#include <linux/comedi/comedi_8254.h>



static unsigned int __i8254_read(struct comedi_8254 *i8254, unsigned int reg)

static unsigned int i8254_io8_cb(struct comedi_8254 *i8254, int dir,

				unsigned int reg, unsigned int val)

{

	unsigned int reg_offset = (reg * i8254->iosize) << i8254->regshift;

	unsigned int val;

	unsigned long iobase = i8254->context;

	unsigned int reg_offset = (reg * I8254_IO8) << i8254->regshift;



	switch (i8254->iosize) {

	default:

	case I8254_IO8:

		if (i8254->mmio)

			val = readb(i8254->mmio + reg_offset);

		else

			val = inb(i8254->iobase + reg_offset);

		break;

	case I8254_IO16:

		if (i8254->mmio)

			val = readw(i8254->mmio + reg_offset);

		else

			val = inw(i8254->iobase + reg_offset);

		break;

	case I8254_IO32:

		if (i8254->mmio)

			val = readl(i8254->mmio + reg_offset);

		else

			val = inl(i8254->iobase + reg_offset);

		break;

	if (dir) {

		outb(val, iobase + reg_offset);

		return 0;

	} else {

		return inb(iobase + reg_offset);

	}

	return val & 0xff;

}



static void __i8254_write(struct comedi_8254 *i8254,

			  unsigned int val, unsigned int reg)

static unsigned int i8254_io16_cb(struct comedi_8254 *i8254, int dir,

				  unsigned int reg, unsigned int val)

{

	unsigned int reg_offset = (reg * i8254->iosize) << i8254->regshift;

	unsigned long iobase = i8254->context;

	unsigned int reg_offset = (reg * I8254_IO16) << i8254->regshift;



	switch (i8254->iosize) {

	default:

	case I8254_IO8:

		if (i8254->mmio)

			writeb(val, i8254->mmio + reg_offset);

		else

			outb(val, i8254->iobase + reg_offset);

		break;

	case I8254_IO16:

		if (i8254->mmio)

			writew(val, i8254->mmio + reg_offset);

		else

			outw(val, i8254->iobase + reg_offset);

		break;

	case I8254_IO32:

		if (i8254->mmio)

			writel(val, i8254->mmio + reg_offset);

		else

			outl(val, i8254->iobase + reg_offset);

		break;

	if (dir) {

		outw(val, iobase + reg_offset);

		return 0;

	} else {

		return inw(iobase + reg_offset);

	}

}



static unsigned int i8254_io32_cb(struct comedi_8254 *i8254, int dir,

				  unsigned int reg, unsigned int val)

{

	unsigned long iobase = i8254->context;

	unsigned int reg_offset = (reg * I8254_IO32) << i8254->regshift;



	if (dir) {

		outl(val, iobase + reg_offset);

		return 0;

	} else {

		return inl(iobase + reg_offset);

	}

}



static unsigned int i8254_mmio8_cb(struct comedi_8254 *i8254, int dir,

				   unsigned int reg, unsigned int val)

{

	void __iomem *mmiobase = (void __iomem *)i8254->context;

	unsigned int reg_offset = (reg * I8254_IO8) << i8254->regshift;



	if (dir) {

		writeb(val, mmiobase + reg_offset);

		return 0;

	} else {

		return readb(mmiobase + reg_offset);

	}

}



static unsigned int i8254_mmio16_cb(struct comedi_8254 *i8254, int dir,

				    unsigned int reg, unsigned int val)

{

	void __iomem *mmiobase = (void __iomem *)i8254->context;

	unsigned int reg_offset = (reg * I8254_IO16) << i8254->regshift;



	if (dir) {

		writew(val, mmiobase + reg_offset);

		return 0;

	} else {

		return readw(mmiobase + reg_offset);

	}

}



static unsigned int i8254_mmio32_cb(struct comedi_8254 *i8254, int dir,

				    unsigned int reg, unsigned int val)

{

	void __iomem *mmiobase = (void __iomem *)i8254->context;

	unsigned int reg_offset = (reg * I8254_IO32) << i8254->regshift;



	if (dir) {

		writel(val, mmiobase + reg_offset);

		return 0;

	} else {

		return readl(mmiobase + reg_offset);

	}

}



static unsigned int __i8254_read(struct comedi_8254 *i8254, unsigned int reg)

{

	return 0xff & i8254->iocb(i8254, 0, reg, 0);

}



static void __i8254_write(struct comedi_8254 *i8254,

			  unsigned int val, unsigned int reg)

{

	i8254->iocb(i8254, 1, reg, val);

}



/**

 * comedi_8254_status - return the status of a counter

 * @i8254:	comedi_8254 struct for the timer
@@ -571,8 +609,8 @@ void comedi_8254_subdevice_init(struct comedi_subdevice *s, 
}

EXPORT_SYMBOL_GPL(comedi_8254_subdevice_init);



static struct comedi_8254 *__i8254_init(unsigned long iobase,

					void __iomem *mmio,

static struct comedi_8254 *__i8254_init(comedi_8254_iocb_fn *iocb,

					unsigned long context,

					unsigned int osc_base,

					unsigned int iosize,

					unsigned int regshift)
@@ -585,12 +623,15 @@ static struct comedi_8254 *__i8254_init(unsigned long iobase, 
	      iosize == I8254_IO32))

		return NULL;



	if (!iocb)

		return NULL;



	i8254 = kzalloc(sizeof(*i8254), GFP_KERNEL);

	if (!i8254)

		return NULL;



	i8254->iobase	= iobase;

	i8254->mmio	= mmio;

	i8254->iocb	= iocb;

	i8254->context	= context;

	i8254->iosize	= iosize;

	i8254->regshift	= regshift;
@@ -617,7 +658,22 @@ struct comedi_8254 *comedi_8254_init(unsigned long iobase, 
				     unsigned int iosize,

				     unsigned int regshift)

{

	return __i8254_init(iobase, NULL, osc_base, iosize, regshift);

	comedi_8254_iocb_fn *iocb;



	switch (iosize) {

	case I8254_IO8:

		iocb = i8254_io8_cb;

		break;

	case I8254_IO16:

		iocb = i8254_io16_cb;

		break;

	case I8254_IO32:

		iocb = i8254_io32_cb;

		break;

	default:

		return NULL;

	}

	return __i8254_init(iocb, iobase, osc_base, iosize, regshift);

}

EXPORT_SYMBOL_GPL(comedi_8254_init);
@@ -634,7 +690,22 @@ struct comedi_8254 *comedi_8254_mm_init(void __iomem *mmio, 
					unsigned int iosize,

					unsigned int regshift)

{

	return __i8254_init(0, mmio, osc_base, iosize, regshift);

	comedi_8254_iocb_fn *iocb;



	switch (iosize) {

	case I8254_IO8:

		iocb = i8254_mmio8_cb;

		break;

	case I8254_IO16:

		iocb = i8254_mmio16_cb;

		break;

	case I8254_IO32:

		iocb = i8254_mmio32_cb;

		break;

	default:

		return NULL;

	}

	return __i8254_init(iocb, (unsigned long)mmio, osc_base, iosize, regshift);

}

EXPORT_SYMBOL_GPL(comedi_8254_mm_init);

include/linux/comedi/comedi_8254.h

+18 −4
Original line number Diff line number Diff line
@@ -57,10 +57,24 @@ struct comedi_subdevice; 
/* counter maps zero to 0x10000 */

#define I8254_MAX_COUNT			0x10000



struct comedi_8254;



/**

 * typedef comedi_8254_iocb_fn - call-back function type for 8254 register access

 * @i8254:		pointer to struct comedi_8254

 * @dir:		direction (0 = read, 1 = write)

 * @reg:		register number

 * @val:		value to write

 *

 * Return: Register value when reading, 0 when writing.

 */

typedef unsigned int comedi_8254_iocb_fn(struct comedi_8254 *i8254, int dir,

					 unsigned int reg, unsigned int val);



/**

 * struct comedi_8254 - private data used by this module

 * @iobase:		PIO base address of the registers (in/out)

 * @mmio:		MMIO base address of the registers (read/write)

 * @iocb:		I/O call-back function for register access

 * @context:		context for register access (e.g. a base address)

 * @iosize:		I/O size used to access the registers (b/w/l)

 * @regshift:		register gap shift

 * @osc_base:		cascaded oscillator speed in ns
@@ -76,8 +90,8 @@ struct comedi_subdevice; 
 * @insn_config:	driver specific (*insn_config) callback

 */

struct comedi_8254 {

	unsigned long iobase;

	void __iomem *mmio;

	comedi_8254_iocb_fn *iocb;

	unsigned long context;

	unsigned int iosize;

	unsigned int regshift;

	unsigned int osc_base;