diff options
Diffstat (limited to 'kernel/drivers/gpio/gpio-it8761e.c')
| -rw-r--r-- | kernel/drivers/gpio/gpio-it8761e.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/kernel/drivers/gpio/gpio-it8761e.c b/kernel/drivers/gpio/gpio-it8761e.c new file mode 100644 index 000000000..dadfc245c --- /dev/null +++ b/kernel/drivers/gpio/gpio-it8761e.c @@ -0,0 +1,230 @@ +/* + * 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"); |