gpio: introduce it8761e_gpio driver for IT8761E Super I/O chip

Signed-off-by: Denis Turischev <denis@compulab.co.il>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 238 insertions, 0 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index c5cc7d9d88e3..a4cdbd51b1c6 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -70,6 +70,12 @@ config GPIO_MAX730X
 
 comment "Memory mapped GPIO expanders:"
 
+config GPIO_IT8761E
+        tristate "IT8761E GPIO support"
+        depends on GPIOLIB
+        help
+          Say yes here to support GPIO functionality of IT8761E super I/O chip.
+
 config GPIO_PL061
         bool "PrimeCell PL061 GPIO support"
         depends on ARM_AMBA
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 508a1b202cdb..128abf8a98da 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -22,5 +22,6 @@ obj-$(CONFIG_GPIO_UCB1400)	+= ucb1400_gpio.o
 obj-$(CONFIG_GPIO_XILINX)       += xilinx_gpio.o
 obj-$(CONFIG_GPIO_CS5535)       += cs5535-gpio.o
 obj-$(CONFIG_GPIO_BT8XX)        += bt8xxgpio.o
+obj-$(CONFIG_GPIO_IT8761E)      += it8761e_gpio.o
 obj-$(CONFIG_GPIO_VR41XX)       += vr41xx_giu.o
 obj-$(CONFIG_GPIO_WM831X)       += wm831x-gpio.o
diff --git a/drivers/gpio/it8761e_gpio.c b/drivers/gpio/it8761e_gpio.c
new file mode 100644
index 000000000000..753219cf993a
--- /dev/null
+++ b/drivers/gpio/it8761e_gpio.c
@@ -0,0 +1,231 @@
+/*
+ *  it8761_gpio.c - 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 % 7;
+        reg = (gpio_num >= 7) ? 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 % 7;
+        io_reg = (gpio_num >= 7) ? 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 % 7;
+        reg = (gpio_num >= 7) ? 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 % 7;
+        io_reg = (gpio_num >= 7) ? 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 = 14;
+
+        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");