gpio.c

该文件是rt_linux

/* $Id: gpio.c,v 1.17 2002/06/17 15:53:01 johana Exp $
 *
 * Etrax general port I/O device
 *
 * Copyright (c) 1999, 2000, 2001, 2002 Axis Communications AB
 *
 * Authors:    Bjorn Wesen      (initial version)
 *             Ola Knutsson     (LED handling)
 *             Johan Adolfsson  (read/set directions, write, port G)
 *
 * $Log: gpio.c,v $
 * Revision 1.17  2002/06/17 15:53:01  johana
 * Added IO_READ_INBITS, IO_READ_OUTBITS, IO_SETGET_INPUT and IO_SETGET_OUTPUT
 * that take a pointer as argument and thus can handle 32 bit ports (G)
 * correctly.
 * These should be used instead of IO_READBITS, IO_SETINPUT and IO_SETOUTPUT.
 * (especially if Port G bit 31 is used)
 *
 * Revision 1.16  2002/06/17 09:59:51  johana
 * Returning 32 bit values in the ioctl return value doesn't work if bit
 * 31 is set (could happen for port G), so mask it of with 0x7FFFFFFF.
 * A new set of ioctl's will be added.
 *
 * Revision 1.15  2002/05/06 13:19:13  johana
 * IO_SETINPUT returns mask with bit set = inputs for PA and PB as well.
 *
 * Revision 1.14  2002/04/12 12:01:53  johana
 * Use global r_port_g_data_shadow.
 * Moved gpio_init_port_g() closer to gpio_init() and marked it __init.
 *
 * Revision 1.13  2002/04/10 12:03:55  johana
 * Added support for port G /dev/gpiog (minor 3).
 * Changed indentation on switch cases.
 * Fixed other spaces to tabs.
 *
 * Revision 1.12  2001/11/12 19:42:15  pkj
 * * Corrected return values from gpio_leds_ioctl().
 * * Fixed compiler warnings.
 *
 * Revision 1.11  2001/10/30 14:39:12  johana
 * Added D() around gpio_write printk.
 *
 * Revision 1.10  2001/10/25 10:24:42  johana
 * Added IO_CFG_WRITE_MODE ioctl and write method that can do fast
 * bittoggling in the kernel. (This speeds up programming an FPGA with 450kB
 * from ~60 seconds to 4 seconds).
 * Added save_flags/cli/restore_flags in ioctl.
 *
 * Revision 1.9  2001/05/04 14:16:07  matsfg
 * Corrected spelling error
 *
 * Revision 1.8  2001/04/27 13:55:26  matsfg
 * Moved initioremap.
 * Turns off all LEDS on init.
 * Added support for shutdown and powerbutton.
 *
 * Revision 1.7  2001/04/04 13:30:08  matsfg
 * Added bitset and bitclear for leds. Calls init_ioremap to set up memmapping
 *
 * Revision 1.6  2001/03/26 16:03:06  bjornw
 * Needs linux/config.h
 *
 * Revision 1.5  2001/03/26 14:22:03  bjornw
 * Namechange of some config options
 *
 * Revision 1.4  2001/02/27 13:52:48  bjornw
 * malloc.h -> slab.h
 *
 * Revision 1.3  2001/01/24 15:06:48  bjornw
 * gpio_wq correct type
 *
 * Revision 1.2  2001/01/18 16:07:30  bjornw
 * 2.4 port
 *
 * Revision 1.1  2001/01/18 15:55:16  bjornw
 * Verbatim copy of etraxgpio.c from elinux 2.0 added
 *
 *
 */

#include <linux/config.h>

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/poll.h>
#include <linux/init.h>

#include <asm/etraxgpio.h>
#include <asm/svinto.h>
#include <asm/io.h>
#include <asm/system.h>

#define GPIO_MAJOR 120  /* experimental MAJOR number */

#define D(x)

static char gpio_name[] = "etrax gpio";

#if 0
static wait_queue_head_t *gpio_wq;
#endif

static int gpio_ioctl(struct inode *inode, struct file *file,
		      unsigned int cmd, unsigned long arg);
static ssize_t gpio_write(struct file * file, const char * buf, size_t count,
                          loff_t *off);
static int gpio_open(struct inode *inode, struct file *filp);
static int gpio_release(struct inode *inode, struct file *filp);
static unsigned int gpio_poll(struct file *filp, struct poll_table_struct *wait);

/* private data per open() of this driver */

struct gpio_private {
	struct gpio_private *next;
	/* These fields are for PA and PB only */
	volatile unsigned char *port, *shadow;
	volatile unsigned char *dir, *dir_shadow;
	unsigned char changeable_dir;
	unsigned char changeable_bits;
	unsigned char clk_mask;
	unsigned char data_mask;
	unsigned char write_msb;
	unsigned char pad1, pad2, pad3;
	/* These fields are generic */
	unsigned long highalarm, lowalarm;
	wait_queue_head_t alarm_wq;
	int minor;
};

/* linked list of alarms to check for */

static struct gpio_private *alarmlist = 0;

/* Port A and B use 8 bit access, but Port G is 32 bit */
#define NUM_PORTS (GPIO_MINOR_B+1)

static volatile unsigned char *ports[NUM_PORTS] = { 
	R_PORT_PA_DATA, 
	R_PORT_PB_DATA,
};
static volatile unsigned char *shads[NUM_PORTS] = {
	&port_pa_data_shadow, 
	&port_pb_data_shadow
};

/* What direction bits that are user changeable 1=changeable*/
#ifndef CONFIG_ETRAX_PA_CHANGEABLE_DIR
#define CONFIG_ETRAX_PA_CHANGEABLE_DIR 0x00
#endif
#ifndef CONFIG_ETRAX_PB_CHANGEABLE_DIR
#define CONFIG_ETRAX_PB_CHANGEABLE_DIR 0x00
#endif

#ifndef CONFIG_ETRAX_PA_CHANGEABLE_BITS
#define CONFIG_ETRAX_PA_CHANGEABLE_BITS 0xFF
#endif
#ifndef CONFIG_ETRAX_PB_CHANGEABLE_BITS
#define CONFIG_ETRAX_PB_CHANGEABLE_BITS 0xFF
#endif


static unsigned char changeable_dir[NUM_PORTS] = { 
	CONFIG_ETRAX_PA_CHANGEABLE_DIR,
	CONFIG_ETRAX_PB_CHANGEABLE_DIR 
};
static unsigned char changeable_bits[NUM_PORTS] = { 
	CONFIG_ETRAX_PA_CHANGEABLE_BITS,
	CONFIG_ETRAX_PB_CHANGEABLE_BITS 
};

static volatile unsigned char *dir[NUM_PORTS] = { 
	R_PORT_PA_DIR, 
	R_PORT_PB_DIR 
};

static volatile unsigned char *dir_shadow[NUM_PORTS] = {
	&port_pa_dir_shadow, 
	&port_pb_dir_shadow 
};

/* Port G is 32 bit, handle it special, some bits are both inputs 
   and outputs at the same time, only some of the bits can change direction
   and some of them in groups of 8 bit. */
static unsigned long changeable_dir_g;
static unsigned long dir_g_in_bits;
static unsigned long dir_g_out_bits;
static unsigned long dir_g_shadow; /* 1=output */

#define USE_PORTS(priv) ((priv)->minor <= GPIO_MINOR_B)



static unsigned int 
gpio_poll(struct file *filp,
	  struct poll_table_struct *wait)
{
	/* TODO poll on alarms! */
#if 0
	if (!ANYTHING_WANTED) {
		D(printk("gpio_select sleeping task\n"));
		select_wait(&gpio_wq, table);
		return 0;
	}
	D(printk("gpio_select ready\n"));
#endif
	return 1;
}

static ssize_t gpio_write(struct file * file, const char * buf, size_t count,
                          loff_t *off)
{
	struct gpio_private *priv = (struct gpio_private *)file->private_data;
	unsigned char data, clk_mask, data_mask, write_msb;
	unsigned long flags;
	ssize_t retval = count;
	if (priv->minor !=GPIO_MINOR_A && priv->minor != GPIO_MINOR_B) {
		return -EFAULT;
	}
    
	if (verify_area(VERIFY_READ, buf, count)) {
		return -EFAULT;
	}
	clk_mask = priv->clk_mask;
	data_mask = priv->data_mask;
	/* It must have been configured using the IO_CFG_WRITE_MODE */
	/* Perhaps a better error code? */
	if (clk_mask == 0 || data_mask == 0) {
		return -EPERM;
	}
	write_msb = priv->write_msb;
	D(printk("gpio_write: %lu to data 0x%02X clk 0x%02X msb: %i\n",count, data_mask, clk_mask, write_msb));
	while (count--) {
		int i;
		data = *buf++;
		if (priv->write_msb) {
			for (i = 7; i >= 0;i--) {
				save_flags(flags); cli();
				*priv->port = *priv->shadow &= ~clk_mask;
				if (data & 1<<i)
					*priv->port = *priv->shadow |= data_mask;
				else
					*priv->port = *priv->shadow &= ~data_mask;
			/* For FPGA: min 5.0ns (DCC) before CCLK high */
				*priv->port = *priv->shadow |= clk_mask;
				restore_flags(flags);
			}
		} else {
			for (i = 0; i <= 7;i++) {
				save_flags(flags); cli();
				*priv->port = *priv->shadow &= ~clk_mask;
				if (data & 1<<i)
					*priv->port = *priv->shadow |= data_mask;
				else
					*priv->port = *priv->shadow &= ~data_mask;
			/* For FPGA: min 5.0ns (DCC) before CCLK high */
				*priv->port = *priv->shadow |= clk_mask;
				restore_flags(flags);
			}
		}
	}
	return retval;
}



static int
gpio_open(struct inode *inode, struct file *filp)
{
	struct gpio_private *priv;
	int p = MINOR(inode->i_rdev);

	if (p > GPIO_MINOR_LAST)
		return -EINVAL;

	priv = (struct gpio_private *)kmalloc(sizeof(struct gpio_private), 
					      GFP_KERNEL);

	if (!priv)
		return -ENOMEM;

	priv->minor = p;

	/* initialize the io/alarm struct and link it into our alarmlist */

	priv->next = alarmlist;
	alarmlist = priv;
	if (USE_PORTS(priv)) { /* A and B */
		priv->port = ports[p];
		priv->shadow = shads[p];
		priv->dir = dir[p];
		priv->dir_shadow = dir_shadow[p];
		priv->changeable_dir = changeable_dir[p];
		priv->changeable_bits = changeable_bits[p];
	} else {
		priv->port = NULL;
		priv->shadow = NULL;
		priv->dir = NULL;
		priv->dir_shadow = NULL;
		priv->changeable_dir = 0;
		priv->changeable_bits = 0;
	}

	priv->highalarm = 0;
	priv->lowalarm = 0;
	priv->clk_mask = 0;
	priv->data_mask = 0;
	init_waitqueue_head(&priv->alarm_wq);

	filp->private_data = (void *)priv;

	return 0;
}

static int
gpio_release(struct inode *inode, struct file *filp)
{
	struct gpio_private *p = alarmlist;
	struct gpio_private *todel = (struct gpio_private *)filp->private_data;

	/* unlink from alarmlist and free the private structure */

	if (p == todel) {
		alarmlist = todel->next;
	} else {
		while (p->next != todel)
			p = p->next;
		p->next = todel->next;
	}

	kfree(todel);

	return 0;
}

/* Main device API. ioctl's to read/set/clear bits, as well as to 
 * set alarms to wait for using a subsequent select().
 */

unsigned long inline setget_input(struct gpio_private *priv, unsigned long arg)
{
	/* Set direction 0=unchanged 1=input, 
	 * return mask with 1=input 
	 */
	unsigned long flags;
	if (USE_PORTS(priv)) {
		save_flags(flags); cli();
		*priv->dir = *priv->dir_shadow &= 
		~((unsigned char)arg & priv->changeable_dir);
		restore_flags(flags);
		return ~(*priv->dir_shadow);
	} else if (priv->minor == GPIO_MINOR_G) {
		/* We must fiddle with R_GEN_CONFIG to change dir */
		if (((arg & dir_g_in_bits) != arg) && 
		    (arg & changeable_dir_g)) {
			arg &= changeable_dir_g;
			/* Clear bits in genconfig to set to input */
			if (arg & (1<<0)) {
				genconfig_shadow &= ~IO_MASK(R_GEN_CONFIG,g0dir);
				dir_g_in_bits |= (1<<0);
				dir_g_out_bits &= ~(1<<0);
			}
			if ((arg & 0x0000FF00) == 0x0000FF00) {
				genconfig_shadow &= ~IO_MASK(R_GEN_CONFIG,g8_15dir);
				dir_g_in_bits |= 0x0000FF00;
				dir_g_out_bits &= ~0x0000FF00;
			}
			if ((arg & 0x00FF0000) == 0x00FF0000) {
				genconfig_shadow &= ~IO_MASK(R_GEN_CONFIG,g16_23dir);
				dir_g_in_bits |= 0x00FF0000;
				dir_g_out_bits &= ~0x00FF0000;
			}
			if (arg & (1<<24)) {
				genconfig_shadow &= ~IO_MASK(R_GEN_CONFIG,g24dir);
				dir_g_in_bits |= (1<<24);
				dir_g_out_bits &= ~(1<<24);
			}
			printk("gpio: SETINPUT on port G set "
				"genconfig to 0x%08lX "
				"in_bits: 0x%08lX "
				"out_bits: 0x%08lX\n",