drivers/gpio/it8761e_gpio.c

   1 /*
   2  *  it8761_gpio.c - GPIO interface for IT8761E Super I/O chip
   3  *
   4  *  Author: Denis Turischev <denis@compulab.co.il>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License 2 as published
   8  *  by the Free Software Foundation.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; see the file COPYING.  If not, write to
  17  *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20 #include <linux/init.h>
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/io.h>
  24 #include <linux/errno.h>
  25 #include <linux/ioport.h>
  26
  27 #include <linux/gpio.h>
  28
  29 #define SIO_CHIP_ID             0x8761
  30 #define CHIP_ID_HIGH_BYTE       0x20
  31 #define CHIP_ID_LOW_BYTE        0x21
  32
  33 static u8 ports[2] = { 0x2e, 0x4e };
  34 static u8 port;
  35
  36 static DEFINE_SPINLOCK(sio_lock);
  37
  38 #define GPIO_NAME               "it8761-gpio"
  39 #define GPIO_BA_HIGH_BYTE       0x60
  40 #define GPIO_BA_LOW_BYTE        0x61
  41 #define GPIO_IOSIZE             4
  42 #define GPIO1X_IO               0xf0
  43 #define GPIO2X_IO               0xf1
  44
  45 static u16 gpio_ba;
  46
  47 static u8 read_reg(u8 addr, u8 port)
  48 {
  49         outb(addr, port);
  50         return inb(port + 1);
  51 }
  52
  53 static void write_reg(u8 data, u8 addr, u8 port)
  54 {
  55         outb(addr, port);
  56         outb(data, port + 1);
  57 }
  58
  59 static void enter_conf_mode(u8 port)
  60 {
  61         outb(0x87, port);
  62         outb(0x61, port);
  63         outb(0x55, port);
  64         outb((port == 0x2e) ? 0x55 : 0xaa, port);
  65 }
  66
  67 static void exit_conf_mode(u8 port)
  68 {
  69         outb(0x2, port);
  70         outb(0x2, port + 1);
  71 }
  72
  73 static void enter_gpio_mode(u8 port)
  74 {
  75         write_reg(0x2, 0x7, port);
  76 }
  77
  78 static int it8761e_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
  79 {
  80         u16 reg;
  81         u8 bit;
  82
  83         bit = gpio_num % 8;
  84         reg = (gpio_num >= 8) ? gpio_ba + 1 : gpio_ba;
  85
  86         return !!(inb(reg) & (1 << bit));
  87 }
  88
  89 static int it8761e_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
  90 {
  91         u8 curr_dirs;
  92         u8 io_reg, bit;
  93
  94         bit = gpio_num % 8;
  95         io_reg = (gpio_num >= 8) ? GPIO2X_IO : GPIO1X_IO;
  96
  97         spin_lock(&sio_lock);
  98
  99         enter_conf_mode(port);
 100         enter_gpio_mode(port);
 101
 102         curr_dirs = read_reg(io_reg, port);
 103
 104         if (curr_dirs & (1 << bit))
 105                 write_reg(curr_dirs & ~(1 << bit), io_reg, port);
 106
 107         exit_conf_mode(port);
 108
 109         spin_unlock(&sio_lock);
 110         return 0;
 111 }
 112
 113 static void it8761e_gpio_set(struct gpio_chip *gc,
 114                                 unsigned gpio_num, int val)
 115 {
 116         u8 curr_vals, bit;
 117         u16 reg;
 118
 119         bit = gpio_num % 8;
 120         reg = (gpio_num >= 8) ? gpio_ba + 1 : gpio_ba;
 121
 122         spin_lock(&sio_lock);
 123
 124         curr_vals = inb(reg);
 125         if (val)
 126                 outb(curr_vals | (1 << bit) , reg);
 127         else
 128                 outb(curr_vals & ~(1 << bit), reg);
 129
 130         spin_unlock(&sio_lock);
 131 }
 132
 133 static int it8761e_gpio_direction_out(struct gpio_chip *gc,
 134                                         unsigned gpio_num, int val)
 135 {
 136         u8 curr_dirs, io_reg, bit;
 137
 138         bit = gpio_num % 8;
 139         io_reg = (gpio_num >= 8) ? GPIO2X_IO : GPIO1X_IO;
 140
 141         it8761e_gpio_set(gc, gpio_num, val);
 142
 143         spin_lock(&sio_lock);
 144
 145         enter_conf_mode(port);
 146         enter_gpio_mode(port);
 147
 148         curr_dirs = read_reg(io_reg, port);
 149
 150         if (!(curr_dirs & (1 << bit)))
 151                 write_reg(curr_dirs | (1 << bit), io_reg, port);
 152
 153         exit_conf_mode(port);
 154
 155         spin_unlock(&sio_lock);
 156         return 0;
 157 }
 158
 159 static struct gpio_chip it8761e_gpio_chip = {
 160         .label                  = GPIO_NAME,
 161         .owner                  = THIS_MODULE,
 162         .get                    = it8761e_gpio_get,
 163         .direction_input        = it8761e_gpio_direction_in,
 164         .set                    = it8761e_gpio_set,
 165         .direction_output       = it8761e_gpio_direction_out,
 166 };
 167
 168 static int __init it8761e_gpio_init(void)
 169 {
 170         int i, id, err;
 171
 172         /* chip and port detection */
 173         for (i = 0; i < ARRAY_SIZE(ports); i++) {
 174                 spin_lock(&sio_lock);
 175                 enter_conf_mode(ports[i]);
 176
 177                 id = (read_reg(CHIP_ID_HIGH_BYTE, ports[i]) << 8) +
 178                                 read_reg(CHIP_ID_LOW_BYTE, ports[i]);
 179
 180                 exit_conf_mode(ports[i]);
 181                 spin_unlock(&sio_lock);
 182
 183                 if (id == SIO_CHIP_ID) {
 184                         port = ports[i];
 185                         break;
 186                 }
 187         }
 188
 189         if (!port)
 190                 return -ENODEV;
 191
 192         /* fetch GPIO base address */
 193         enter_conf_mode(port);
 194         enter_gpio_mode(port);
 195         gpio_ba = (read_reg(GPIO_BA_HIGH_BYTE, port) << 8) +
 196                                 read_reg(GPIO_BA_LOW_BYTE, port);
 197         exit_conf_mode(port);
 198
 199         if (!request_region(gpio_ba, GPIO_IOSIZE, GPIO_NAME))
 200                 return -EBUSY;
 201
 202         it8761e_gpio_chip.base = -1;
 203         it8761e_gpio_chip.ngpio = 16;
 204
 205         err = gpiochip_add(&it8761e_gpio_chip);
 206         if (err < 0)
 207                 goto gpiochip_add_err;
 208
 209         return 0;
 210
 211 gpiochip_add_err:
 212         release_region(gpio_ba, GPIO_IOSIZE);
 213         gpio_ba = 0;
 214         return err;
 215 }
 216
 217 static void __exit it8761e_gpio_exit(void)
 218 {
 219         if (gpio_ba) {
 220                 int ret = gpiochip_remove(&it8761e_gpio_chip);
 221
 222                 WARN(ret, "%s(): gpiochip_remove() failed, ret=%d\n",
 223                                 __func__, ret);
 224
 225                 release_region(gpio_ba, GPIO_IOSIZE);
 226                 gpio_ba = 0;
 227         }
 228 }
 229 module_init(it8761e_gpio_init);
 230 module_exit(it8761e_gpio_exit);
 231
 232 MODULE_AUTHOR("Denis Turischev <denis@compulab.co.il>");
 233 MODULE_DESCRIPTION("GPIO interface for IT8761E Super I/O chip");
 234 MODULE_LICENSE("GPL");