[PATCH] gpio: add support for ITE IT87xx Super I/O GPIO.
From: Diego Elio PettenÃ
Date: Fri Mar 16 2012 - 15:46:13 EST
The driver is currently written for IT8728, but the code in it87_wdt
suggest it would work the same way on many other versions.
This is just a first step to verify the working status of the code,
and might require moving to a MFD approach to share with hwmon/it87
and it87_wdt, as they all share the same access to the Super I/O chip.
That would also allow to set a few more opitons so that you could for
instance change the function selection of a few pins from their
default to GPIO pins.
It does not yet support the polarity-inversion register that is
allowed by the chipset, which might require sysfs attributes per-gpio.
CC: Grant Likely <grant.likely@xxxxxxxxxxxx>
CC: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
Signed-off-by: Diego Elio Pettenà <flameeyes@xxxxxxxxxxxx>
---
MAINTAINERS | 5 +
drivers/gpio/Kconfig | 11 ++
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-it87.c | 397 ++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 414 insertions(+), 0 deletions(-)
create mode 100644 drivers/gpio/gpio-it87.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 553ac10..a196f14 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3692,6 +3692,11 @@ S: Maintained
F: Documentation/hwmon/it87
F: drivers/hwmon/it87.c
+IT87xx GPIO DRIVER
+M: Diego Elio Pettenà <flameeyes@xxxxxxxxxxxx>
+S: Maintained
+F: drivers/gpio/gpio-it87.c
+
IVTV VIDEO4LINUX DRIVER
M: Andy Walls <awalls@xxxxxxxxxxxxxxxx>
L: ivtv-devel@xxxxxxxxxxxxxx (moderated for non-subscribers)
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 3359f1e..8dc26b7 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -91,6 +91,17 @@ config GPIO_IT8761E
help
Say yes here to support GPIO functionality of IT8761E super I/O chip.
+config GPIO_IT87
+ tristate "IT87xx GPIO support"
+ depends on X86 # unconditional access to IO space.
+ help
+ Say yes here to support GPIO functionality of IT87xx Super I/O chips.
+
+ This driver currently supports ITE IT8728 Super I/O chips.
+
+ To compile this driver as a module, choose M here: the module will
+ be called gpio_it87
+
config GPIO_EP93XX
def_bool y
depends on ARCH_EP93XX
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 41fe67f..affe510 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_ARCH_DAVINCI) += gpio-davinci.o
obj-$(CONFIG_GPIO_EP93XX) += gpio-ep93xx.o
obj-$(CONFIG_GPIO_ICH) += gpio-ich.o
obj-$(CONFIG_GPIO_IT8761E) += gpio-it8761e.o
+obj-$(CONFIG_GPIO_IT87) += gpio-it87.o
obj-$(CONFIG_GPIO_JANZ_TTL) += gpio-janz-ttl.o
obj-$(CONFIG_ARCH_KS8695) += gpio-ks8695.o
obj-$(CONFIG_GPIO_LANGWELL) += gpio-langwell.o
diff --git a/drivers/gpio/gpio-it87.c b/drivers/gpio/gpio-it87.c
new file mode 100644
index 0000000..958c126
--- /dev/null
+++ b/drivers/gpio/gpio-it87.c
@@ -0,0 +1,397 @@
+/*
+ * GPIO interface for IT87xx Super I/O chips
+ *
+ * Author: Diego Elio Pettenà <flameeyes@xxxxxxxxxxxx>
+ *
+ * Based on it87_wdt.c by Oliver Schuster
+ * gpio-it8761e.c by Denis Turischev
+ *
+ * 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 GPIO_NAME "it87-gpio"
+#define PFX GPIO_NAME ": "
+
+/* Chip Id numbers */
+#define NO_DEV_ID 0xffff
+#define IT8728_ID 0x8728
+
+/* IO Ports */
+#define REG 0x2e
+#define VAL 0x2f
+
+/* Logical device Numbers LDN */
+#define GPIO 0x07
+
+/* Configuration Registers and Functions */
+#define LDNREG 0x07
+#define CHIPID 0x20
+#define CHIPREV 0x22
+
+/* GPIO Simple I/O Base Address registers */
+#define GPIO_BASE 0x62
+#define GPIO_IOSIZE 8
+
+/* GPIO polarity inverting registers base */
+#define GPIO_PS_BASE 0xb0 /* to 0xb4 */
+/* Simple I/O Enable registers base */
+#define GPIO_SE_BASE 0xc0 /* to 0xc4 */
+#define GPIO_SE_SIZE 5
+/* Output Enable registers base */
+#define GPIO_OE_BASE 0xc8 /* to 0xcf */
+
+/* Superio Chip */
+
+static inline int superio_enter(void)
+{
+ /*
+ * Try to reserve REG and REG + 1 for exclusive access.
+ */
+ if (!request_muxed_region(REG, 2, GPIO_NAME))
+ return -EBUSY;
+
+ outb(0x87, REG);
+ outb(0x01, REG);
+ outb(0x55, REG);
+ outb(0x55, REG);
+ return 0;
+}
+
+static inline void superio_exit(void)
+{
+ outb(0x02, REG);
+ outb(0x02, VAL);
+ release_region(REG, 2);
+}
+
+static inline void superio_select(int ldn)
+{
+ outb(LDNREG, REG);
+ outb(ldn, VAL);
+}
+
+static inline int superio_inb(int reg)
+{
+ outb(reg, REG);
+ return inb(VAL);
+}
+
+static inline void superio_outb(int val, int reg)
+{
+ outb(reg, REG);
+ outb(val, VAL);
+}
+
+static inline int superio_inw(int reg)
+{
+ int val;
+ outb(reg++, REG);
+ val = inb(VAL) << 8;
+ outb(reg, REG);
+ val |= inb(VAL);
+ return val;
+}
+
+static inline void superio_outw(int val, int reg)
+{
+ outb(reg++, REG);
+ outb(val >> 8, VAL);
+ outb(reg, REG);
+ outb(val, VAL);
+}
+
+static inline void superio_set_bit(int bit, int reg)
+{
+ u8 curr_val = superio_inb(reg);
+ u8 new_val = curr_val | 1 << bit;
+
+ if (curr_val != new_val)
+ superio_outb(new_val, reg);
+}
+
+static inline void superio_clear_bit(int bit, int reg)
+{
+ u8 curr_val = superio_inb(reg);
+ u8 new_val = curr_val & ~(1 << bit);
+
+ if (curr_val != new_val)
+ superio_outb(new_val, reg);
+}
+
+static u16 gpio_ba;
+
+static int it87_gpio_request(struct gpio_chip *gc, unsigned gpio_num)
+{
+ u8 bit, group;
+ int rc;
+
+ bit = gpio_num % 8;
+ group = (gpio_num / 8);
+
+ if ((rc = superio_enter()))
+ return rc;
+
+ /* enable Simple I/O on the GPIO pin, removing alternate
+ * function; only the first five groups are programmable as
+ * either Simple I/O or alternate function, the final free are
+ * always set to Simple I/O.
+ *
+ * This might differ depending on chip type so it could have
+ * to be made configurable.
+ */
+ if (group >= GPIO_SE_SIZE)
+ superio_set_bit(bit, group + GPIO_SE_BASE);
+
+ /* clear output enable, setting the pin to input, as all the
+ * newly-exported GPIO interfaces are set to input.
+ */
+ superio_clear_bit(bit, group + GPIO_OE_BASE);
+
+ superio_exit();
+
+ return 0;
+}
+
+static int it87_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
+{
+ u16 reg;
+ u8 bit;
+
+ bit = gpio_num % 8;
+ reg = (gpio_num / 8) + gpio_ba;
+
+ return !!(inb(reg) & (1 << bit));
+}
+
+static int it87_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
+{
+ u8 bit, group;
+ int rc;
+
+ bit = gpio_num % 8;
+ group = (gpio_num / 8);
+
+ if ((rc = superio_enter()))
+ return rc;
+
+ /* clear the output enable bit */
+ superio_clear_bit(bit, group + GPIO_OE_BASE);
+
+ superio_exit();
+
+ return 0;
+}
+
+static void it87_gpio_set(struct gpio_chip *gc,
+ unsigned gpio_num, int val)
+{
+ unsigned long flags;
+ u8 curr_vals, bit;
+ u16 reg;
+
+ bit = gpio_num % 8;
+ reg = (gpio_num / 8) + gpio_ba;
+
+ curr_vals = inb(reg);
+ if (val)
+ outb(curr_vals | (1 << bit) , reg);
+ else
+ outb(curr_vals & ~(1 << bit), reg);
+}
+
+static int it87_gpio_direction_out(struct gpio_chip *gc,
+ unsigned gpio_num, int val)
+{
+ u8 bit, group;
+ int rc;
+
+ bit = gpio_num % 8;
+ group = (gpio_num / 8);
+
+ if ((rc = superio_enter()))
+ return rc;
+
+ /* set the output enable bit */
+ superio_set_bit(bit, group + GPIO_OE_BASE);
+
+ it87_gpio_set(gc, gpio_num, val);
+
+ superio_exit();
+
+ return 0;
+}
+
+/* ITE documentation refers to the GPIO registers as coordinates of
+ * group/bit; we alias them as otherwise it becomes hard to find a
+ * correlation between the chip's offsets and the names in the
+ * documentation.
+ */
+static const char *const it87_gpio_aliases[] = {
+ "it87_gp10",
+ "it87_gp11",
+ "it87_gp12",
+ "it87_gp13",
+ "it87_gp14",
+ "it87_gp15",
+ "it87_gp16",
+ "it87_gp17",
+ "it87_gp20",
+ "it87_gp21",
+ "it87_gp22",
+ "it87_gp23",
+ "it87_gp24",
+ "it87_gp25",
+ "it87_gp26",
+ "it87_gp27",
+ "it87_gp30",
+ "it87_gp31",
+ "it87_gp32",
+ "it87_gp33",
+ "it87_gp34",
+ "it87_gp35",
+ "it87_gp36",
+ "it87_gp37",
+ "it87_gp40",
+ "it87_gp41",
+ "it87_gp42",
+ "it87_gp43",
+ "it87_gp44",
+ "it87_gp45",
+ "it87_gp46",
+ "it87_gp47",
+ "it87_gp50",
+ "it87_gp51",
+ "it87_gp52",
+ "it87_gp53",
+ "it87_gp54",
+ "it87_gp55",
+ "it87_gp56",
+ "it87_gp57",
+ "it87_gp60",
+ "it87_gp61",
+ "it87_gp62",
+ "it87_gp63",
+ "it87_gp64",
+ "it87_gp65",
+ "it87_gp66",
+ "it87_gp67",
+ "it87_gp70",
+ "it87_gp71",
+ "it87_gp72",
+ "it87_gp73",
+ "it87_gp74",
+ "it87_gp75",
+ "it87_gp76",
+ "it87_gp77",
+ "it87_gp80",
+ "it87_gp81",
+ "it87_gp82",
+ "it87_gp83",
+ "it87_gp84",
+ "it87_gp85",
+ "it87_gp86",
+ "it87_gp87"
+};
+
+static struct gpio_chip it87_gpio_chip = {
+ .label = GPIO_NAME,
+ .owner = THIS_MODULE,
+ .request = it87_gpio_request,
+ .get = it87_gpio_get,
+ .direction_input = it87_gpio_direction_in,
+ .set = it87_gpio_set,
+ .direction_output = it87_gpio_direction_out,
+ .names = it87_gpio_aliases
+};
+
+static int __init it87_gpio_init(void)
+{
+ int rc = 0;
+ u8 chip_rev;
+ u16 chip_type;
+
+ if ((rc = superio_enter()))
+ return rc;
+
+ chip_type = superio_inw(CHIPID);
+ chip_rev = superio_inb(CHIPREV) & 0x0f;
+ superio_exit();
+
+ switch(chip_type) {
+ case IT8728_ID:
+ break;
+ case NO_DEV_ID:
+ printk(KERN_ERR PFX "no device\n");
+ return -ENODEV;
+ default:
+ printk(KERN_ERR PFX
+ "Unknown Chip found, Chip %04x Revision %x\n",
+ chip_type, chip_rev);
+ return -ENODEV;
+ }
+
+ if ((rc = superio_enter()))
+ return rc;
+
+ superio_select(GPIO);
+
+ /* fetch GPIO base address */
+ gpio_ba = superio_inw(GPIO_BASE);
+
+ superio_exit();
+
+ if (!request_region(gpio_ba, GPIO_IOSIZE, GPIO_NAME))
+ return -EBUSY;
+
+ it87_gpio_chip.base = -1;
+ it87_gpio_chip.ngpio = 64;
+
+ if ((rc = gpiochip_add(&it87_gpio_chip)) < 0)
+ goto gpiochip_add_err;
+
+ return 0;
+
+gpiochip_add_err:
+ release_region(gpio_ba, GPIO_IOSIZE);
+ gpio_ba = 0;
+ return rc;
+}
+
+static void __exit it87_gpio_exit(void)
+{
+ if (gpio_ba) {
+ int ret = gpiochip_remove(&it87_gpio_chip);
+
+ WARN(ret, "%s(): gpiochip_remove() failed, ret=%d\n",
+ __func__, ret);
+
+ release_region(gpio_ba, GPIO_IOSIZE);
+ gpio_ba = 0;
+ }
+}
+module_init(it87_gpio_init);
+module_exit(it87_gpio_exit);
+
+MODULE_AUTHOR("Diego Elio Pettenà <flameeyes@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("GPIO interface for IT87xx Super I/O chips");
+MODULE_LICENSE("GPL");
--
1.7.8.5
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