/*
* AMD CS5535/CS5536 GPIO driver.
* Allows a user space process to play with the GPIO pins.
*
* Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the smems of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*/
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/cdev.h>
#include <linux/ioport.h>
#include <linux/pci.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#define NAME "cs5535_gpio"
MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
MODULE_DESCRIPTION("AMD CS5535/CS5536 GPIO Pin Driver");
MODULE_LICENSE("GPL");
static int major;
module_param(major, int, 0);
MODULE_PARM_DESC(major, "Major device number");
static ulong mask;
module_param(mask, ulong, 0);
MODULE_PARM_DESC(mask, "GPIO channel mask");
#define MSR_LBAR_GPIO 0x5140000C
static u32 gpio_base;
static struct pci_device_id divil_pci[] = {
{ PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA) },
{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA) },
{ } /* NULL entry */
};
static struct cdev cs5535_gpio_cdev;
/* reserve 32 entries even though some aren't usable */
#define CS5535_GPIO_COUNT 32
/* IO block size */
#define CS5535_GPIO_SIZE 256
struct gpio_regmap {
u32 rd_offset;
u32 wr_offset;
char on;
char off;
};
static struct gpio_regmap rm[] =
{
{ 0x30, 0x00, '1', '0' }, /* GPIOx_READ_BACK / GPIOx_OUT_VAL */
{ 0x20, 0x20, 'I', 'i' }, /* GPIOx_IN_EN */
{ 0x04, 0x04, 'O', 'o' }, /* GPIOx_OUT_EN */
{ 0x08, 0x08, 't', 'T' }, /* GPIOx_OUT_OD_EN */
{ 0x18, 0x18, 'P', 'p' }, /* GPIOx_OUT_PU_EN */
{ 0x1c, 0x1c, 'D', 'd' }, /* GPIOx_OUT_PD_EN */
};
/**
* Gets the register offset for the GPIO bank.
* Low (0-15) starts at 0x00, high (16-31) starts at 0x80
*/
static inline u32 cs5535_lowhigh_base(int reg)
{
return (reg & 0x10) << 3;
}
static ssize_t cs5535_gpio_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
u32 m = iminor(file->f_dentry->d_inode);
int i, j;
u32 base = gpio_base + cs5535_lowhigh_base(m);
u32 m0, m1;
char c;
/**
* Creates the mask for atomic bit programming.
* The high 16 bits and the low 16 bits are used to set the mask.
* For example, GPIO 15 maps to 31,15: 0,1 => On; 1,0=> Off
*/
m1 = 1 << (m & 0x0F);
m0 = m1 << 16;
for (i = 0; i < len; ++i) {
if (get_user(c, data+i))
return -EFAULT;
for (j = 0; j < ARRAY_SIZE(rm); j++) {
if (c == rm[j].on) {
outl(m1, base + rm[j].wr_offset);
break;
} else if (c == rm[j].off) {
outl(m0, base + rm[j].wr_offset);
break;
}
}
}
*ppos = 0;
return len;
}
static ssize_t cs5535_gpio_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
u32 m = iminor(file->f_dentry->d_inode);
u32 base = gpio_base + cs5535_lowhigh_base(m);
int rd_bit = 1 << (m & 0x0f);
int i;
char ch;
ssize_t count = 0;
if (*ppos >= ARRAY_SIZE(rm))
return 0;
for (i = *ppos; (i < (*ppos + len)) && (i < ARRAY_SIZE(rm)); i++) {
ch = (inl(base + rm[i].rd_offset) & rd_bit) ?
rm[i].on : rm[i].off;
if (put_user(ch, buf+count))
return -EFAULT;
count++;
}
/* add a line-feed if there is room */
if ((i == ARRAY_SIZE(rm)) && (count < len)) {
put_user('\n', buf + count);
count++;
}
*ppos += count;
return count;
}
static int cs5535_gpio_open(struct inode *inode, struct file *file)
{
u32 m = iminor(inode);
/* the mask says which pins are usable by this driver */
if ((mask & (1 << m)) == 0)
return -EINVAL;
return nonseekable_open(inode, file);
}
static struct file_operations cs5535_gpio_fops = {
.owner = THIS_MODULE,
.write = cs5535_gpio_write,
.read = cs5535_gpio_read,
.open = cs5535_gpio_open
};
static int __init cs5535_gpio_init(void)
{
dev_t dev_id;
u32 low, hi;
int retval;
if (pci_dev_present(divil_pci) == 0) {
printk(KERN_WARNING NAME ": DIVIL not found\n");
return -ENODEV;
}
/* Grab the GPIO I/O range */
rdmsr(MSR_LBAR_GPIO, low, hi);
/* Check the mask and whether GPIO is enabled (sanity check) */
if (hi != 0x0000f001) {
printk(KERN_WARNING NAME ": GPIO not enabled\n");
return -ENODEV;
}
/* Mask off the IO base address */
gpio_base = low & 0x0000ff00;
/**
* Some GPIO pins
* 31-29,23 : reserved (always mask out)
* 28 : Power Button
* 26 : PME#
* 22-16 : LPC
* 14,15 : SMBus
* 9,8 : UART1
* 7 : PCI INTB
* 3,4 : UART2/DDC
* 2 : IDE_IRQ0
* 0 : PCI INTA
*
* If a mask was not specified, be conservative and only allow:
* 1,2,5,6,10-13,24,25,27
*/
if (mask != 0)
mask &= 0x1f7fffff;
else
mask = 0x0b003c66;
if (request_region(gpio_base, CS5535_GPIO_SIZE, NAME) == 0) {
printk(KERN_ERR NAME ": can't allocate I/O for GPIO\n");
return -ENODEV;
}
if (major) {
dev_id = MKDEV(major, 0);
retval = register_chrdev_region(dev_id, CS5535_GPIO_COUNT,
NAME);
} else {
retval = alloc_chrdev_region(&dev_id, 0, CS5535_GPIO_COUNT,
NAME);
major = MAJOR(dev_id);
}
if (retval) {
release_region(gpio_base, CS5535_GPIO_SIZE);
return -1;
}
printk(KERN_DEBUG NAME ": base=%#x mask=%#lx major=%d\n",
gpio_base, mask, major);
cdev_init(&cs5535_gpio_cdev, &cs5535_gpio_fops);
cdev_add(&cs5535_gpio_cdev, dev_id, CS5535_GPIO_COUNT);
return 0;
}
static void __exit cs5535_gpio_cleanup(void)
{
dev_t dev_id = MKDEV(major, 0);
unregister_chrdev_region(dev_id, CS5535_GPIO_COUNT);
if (gpio_base != 0)
release_region(gpio_base, CS5535_GPIO_SIZE);
}
module_init(cs5535_gpio_init);
module_exit(cs5535_gpio_cleanup);
