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/*
* GPIO interface for IT8761E Super I/O chip
*
* Author: Denis Turischev <denis@compulab.co.il>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License 2 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/gpio.h>
#define SIO_CHIP_ID 0x8761
#define CHIP_ID_HIGH_BYTE 0x20
#define CHIP_ID_LOW_BYTE 0x21
static u8 ports[2] = { 0x2e, 0x4e };
static u8 port;
static DEFINE_SPINLOCK(sio_lock);
#define GPIO_NAME "it8761-gpio"
#define GPIO_BA_HIGH_BYTE 0x60
#define GPIO_BA_LOW_BYTE 0x61
#define GPIO_IOSIZE 4
#define GPIO1X_IO 0xf0
#define GPIO2X_IO 0xf1
static u16 gpio_ba;
static u8 read_reg(u8 addr, u8 port)
{
outb(addr, port);
return inb(port + 1);
}
static void write_reg(u8 data, u8 addr, u8 port)
{
outb(addr, port);
outb(data, port + 1);
}
static void enter_conf_mode(u8 port)
{
outb(0x87, port);
outb(0x61, port);
outb(0x55, port);
outb((port == 0x2e) ? 0x55 : 0xaa, port);
}
static void exit_conf_mode(u8 port)
{
outb(0x2, port);
outb(0x2, port + 1);
}
static void enter_gpio_mode(u8 port)
{
write_reg(0x2, 0x7, port);
}
static int it8761e_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
{
u16 reg;
u8 bit;
bit = gpio_num % 8;
reg = (gpio_num >= 8) ? gpio_ba + 1 : gpio_ba;
return !!(inb(reg) & (1 << bit));
}
static int it8761e_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
{
u8 curr_dirs;
u8 io_reg, bit;
bit = gpio_num % 8;
io_reg = (gpio_num >= 8) ? GPIO2X_IO : GPIO1X_IO;
spin_lock(&sio_lock);
enter_conf_mode(port);
enter_gpio_mode(port);
curr_dirs = read_reg(io_reg, port);
if (curr_dirs & (1 << bit))
write_reg(curr_dirs & ~(1 << bit), io_reg, port);
exit_conf_mode(port);
spin_unlock(&sio_lock);
return 0;
}
static void it8761e_gpio_set(struct gpio_chip *gc,
unsigned gpio_num, int val)
{
u8 curr_vals, bit;
u16 reg;
bit = gpio_num % 8;
reg = (gpio_num >= 8) ? gpio_ba + 1 : gpio_ba;
spin_lock(&sio_lock);
curr_vals = inb(reg);
if (val)
outb(curr_vals | (1 << bit), reg);
else
outb(curr_vals & ~(1 << bit), reg);
spin_unlock(&sio_lock);
}
static int it8761e_gpio_direction_out(struct gpio_chip *gc,
unsigned gpio_num, int val)
{
u8 curr_dirs, io_reg, bit;
bit = gpio_num % 8;
io_reg = (gpio_num >= 8) ? GPIO2X_IO : GPIO1X_IO;
it8761e_gpio_set(gc, gpio_num, val);
spin_lock(&sio_lock);
enter_conf_mode(port);
enter_gpio_mode(port);
curr_dirs = read_reg(io_reg, port);
if (!(curr_dirs & (1 << bit)))
write_reg(curr_dirs | (1 << bit), io_reg, port);
exit_conf_mode(port);
spin_unlock(&sio_lock);
return 0;
}
static struct gpio_chip it8761e_gpio_chip = {
.label = GPIO_NAME,
.owner = THIS_MODULE,
.get = it8761e_gpio_get,
.direction_input = it8761e_gpio_direction_in,
.set = it8761e_gpio_set,
.direction_output = it8761e_gpio_direction_out,
};
static int __init it8761e_gpio_init(void)
{
int i, id, err;
/* chip and port detection */
for (i = 0; i < ARRAY_SIZE(ports); i++) {
spin_lock(&sio_lock);
enter_conf_mode(ports[i]);
id = (read_reg(CHIP_ID_HIGH_BYTE, ports[i]) << 8) +
read_reg(CHIP_ID_LOW_BYTE, ports[i]);
exit_conf_mode(ports[i]);
spin_unlock(&sio_lock);
if (id == SIO_CHIP_ID) {
port = ports[i];
break;
}
}
if (!port)
return -ENODEV;
/* fetch GPIO base address */
enter_conf_mode(port);
enter_gpio_mode(port);
gpio_ba = (read_reg(GPIO_BA_HIGH_BYTE, port) << 8) +
read_reg(GPIO_BA_LOW_BYTE, port);
exit_conf_mode(port);
if (!request_region(gpio_ba, GPIO_IOSIZE, GPIO_NAME))
return -EBUSY;
it8761e_gpio_chip.base = -1;
it8761e_gpio_chip.ngpio = 16;
err = gpiochip_add(&it8761e_gpio_chip);
if (err < 0)
goto gpiochip_add_err;
return 0;
gpiochip_add_err:
release_region(gpio_ba, GPIO_IOSIZE);
gpio_ba = 0;
return err;
}
static void __exit it8761e_gpio_exit(void)
{
if (gpio_ba) {
gpiochip_remove(&it8761e_gpio_chip);
release_region(gpio_ba, GPIO_IOSIZE);
gpio_ba = 0;
}
}
module_init(it8761e_gpio_init);
module_exit(it8761e_gpio_exit);
MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
MODULE_DESCRIPTION("GPIO interface for IT8761E Super I/O chip");
MODULE_LICENSE("GPL");
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