diff options
Diffstat (limited to 'drivers/gpio/gpio-it87.c')
| -rw-r--r-- | drivers/gpio/gpio-it87.c | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-it87.c b/drivers/gpio/gpio-it87.c new file mode 100644 index 000000000..f332341fd --- /dev/null +++ b/drivers/gpio/gpio-it87.c @@ -0,0 +1,412 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * GPIO interface for IT87xx Super I/O chips + * + * Author: Diego Elio Pettenò <flameeyes@flameeyes.eu> + * Copyright (c) 2017 Google, Inc. + * + * Based on it87_wdt.c by Oliver Schuster + * gpio-it8761e.c by Denis Turischev + * gpio-stmpe.c by Rabin Vincent + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#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/slab.h> +#include <linux/gpio/driver.h> + +/* Chip Id numbers */ +#define NO_DEV_ID 0xffff +#define IT8613_ID 0x8613 +#define IT8620_ID 0x8620 +#define IT8628_ID 0x8628 +#define IT8718_ID 0x8718 +#define IT8728_ID 0x8728 +#define IT8732_ID 0x8732 +#define IT8761_ID 0x8761 +#define IT8772_ID 0x8772 +#define IT8786_ID 0x8786 + +/* 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 + +/** + * struct it87_gpio - it87-specific GPIO chip + * @chip: the underlying gpio_chip structure + * @lock: a lock to avoid races between operations + * @io_base: base address for gpio ports + * @io_size: size of the port rage starting from io_base. + * @output_base: Super I/O register address for Output Enable register + * @simple_base: Super I/O 'Simple I/O' Enable register + * @simple_size: Super IO 'Simple I/O' Enable register size; this is + * required because IT87xx chips might only provide Simple I/O + * switches on a subset of lines, whereas the others keep the + * same status all time. + */ +struct it87_gpio { + struct gpio_chip chip; + spinlock_t lock; + u16 io_base; + u16 io_size; + u8 output_base; + u8 simple_base; + u8 simple_size; +}; + +static struct it87_gpio it87_gpio_chip = { + .lock = __SPIN_LOCK_UNLOCKED(it87_gpio_chip.lock), +}; + +/* Superio chip access functions; copied from wdt_it87 */ + +static inline int superio_enter(void) +{ + /* + * Try to reserve REG and REG + 1 for exclusive access. + */ + if (!request_muxed_region(REG, 2, KBUILD_MODNAME)) + 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_set_mask(int mask, int reg) +{ + u8 curr_val = superio_inb(reg); + u8 new_val = curr_val | mask; + + if (curr_val != new_val) + superio_outb(new_val, reg); +} + +static inline void superio_clear_mask(int mask, int reg) +{ + u8 curr_val = superio_inb(reg); + u8 new_val = curr_val & ~mask; + + if (curr_val != new_val) + superio_outb(new_val, reg); +} + +static int it87_gpio_request(struct gpio_chip *chip, unsigned gpio_num) +{ + u8 mask, group; + int rc = 0; + struct it87_gpio *it87_gpio = gpiochip_get_data(chip); + + mask = 1 << (gpio_num % 8); + group = (gpio_num / 8); + + spin_lock(&it87_gpio->lock); + + rc = superio_enter(); + if (rc) + goto exit; + + /* not all the IT87xx chips support Simple I/O and not all of + * them allow all the lines to be set/unset to Simple I/O. + */ + if (group < it87_gpio->simple_size) + superio_set_mask(mask, group + it87_gpio->simple_base); + + /* clear output enable, setting the pin to input, as all the + * newly-exported GPIO interfaces are set to input. + */ + superio_clear_mask(mask, group + it87_gpio->output_base); + + superio_exit(); + +exit: + spin_unlock(&it87_gpio->lock); + return rc; +} + +static int it87_gpio_get(struct gpio_chip *chip, unsigned gpio_num) +{ + u16 reg; + u8 mask; + struct it87_gpio *it87_gpio = gpiochip_get_data(chip); + + mask = 1 << (gpio_num % 8); + reg = (gpio_num / 8) + it87_gpio->io_base; + + return !!(inb(reg) & mask); +} + +static int it87_gpio_direction_in(struct gpio_chip *chip, unsigned gpio_num) +{ + u8 mask, group; + int rc = 0; + struct it87_gpio *it87_gpio = gpiochip_get_data(chip); + + mask = 1 << (gpio_num % 8); + group = (gpio_num / 8); + + spin_lock(&it87_gpio->lock); + + rc = superio_enter(); + if (rc) + goto exit; + + /* clear the output enable bit */ + superio_clear_mask(mask, group + it87_gpio->output_base); + + superio_exit(); + +exit: + spin_unlock(&it87_gpio->lock); + return rc; +} + +static void it87_gpio_set(struct gpio_chip *chip, + unsigned gpio_num, int val) +{ + u8 mask, curr_vals; + u16 reg; + struct it87_gpio *it87_gpio = gpiochip_get_data(chip); + + mask = 1 << (gpio_num % 8); + reg = (gpio_num / 8) + it87_gpio->io_base; + + curr_vals = inb(reg); + if (val) + outb(curr_vals | mask, reg); + else + outb(curr_vals & ~mask, reg); +} + +static int it87_gpio_direction_out(struct gpio_chip *chip, + unsigned gpio_num, int val) +{ + u8 mask, group; + int rc = 0; + struct it87_gpio *it87_gpio = gpiochip_get_data(chip); + + mask = 1 << (gpio_num % 8); + group = (gpio_num / 8); + + spin_lock(&it87_gpio->lock); + + rc = superio_enter(); + if (rc) + goto exit; + + /* set the output enable bit */ + superio_set_mask(mask, group + it87_gpio->output_base); + + it87_gpio_set(chip, gpio_num, val); + + superio_exit(); + +exit: + spin_unlock(&it87_gpio->lock); + return rc; +} + +static const struct gpio_chip it87_template_chip = { + .label = KBUILD_MODNAME, + .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, + .base = -1 +}; + +static int __init it87_gpio_init(void) +{ + int rc = 0, i; + u16 chip_type; + u8 chip_rev, gpio_ba_reg; + char *labels, **labels_table; + + struct it87_gpio *it87_gpio = &it87_gpio_chip; + + rc = superio_enter(); + if (rc) + return rc; + + chip_type = superio_inw(CHIPID); + chip_rev = superio_inb(CHIPREV) & 0x0f; + superio_exit(); + + it87_gpio->chip = it87_template_chip; + + switch (chip_type) { + case IT8613_ID: + gpio_ba_reg = 0x62; + it87_gpio->io_size = 8; /* it8613 only needs 6, use 8 for alignment */ + it87_gpio->output_base = 0xc8; + it87_gpio->simple_base = 0xc0; + it87_gpio->simple_size = 6; + it87_gpio->chip.ngpio = 64; /* has 48, use 64 for convenient calc */ + break; + case IT8620_ID: + case IT8628_ID: + gpio_ba_reg = 0x62; + it87_gpio->io_size = 11; + it87_gpio->output_base = 0xc8; + it87_gpio->simple_size = 0; + it87_gpio->chip.ngpio = 64; + break; + case IT8718_ID: + case IT8728_ID: + case IT8732_ID: + case IT8772_ID: + case IT8786_ID: + gpio_ba_reg = 0x62; + it87_gpio->io_size = 8; + it87_gpio->output_base = 0xc8; + it87_gpio->simple_base = 0xc0; + it87_gpio->simple_size = 5; + it87_gpio->chip.ngpio = 64; + break; + case IT8761_ID: + gpio_ba_reg = 0x60; + it87_gpio->io_size = 4; + it87_gpio->output_base = 0xf0; + it87_gpio->simple_size = 0; + it87_gpio->chip.ngpio = 16; + break; + case NO_DEV_ID: + pr_err("no device\n"); + return -ENODEV; + default: + pr_err("Unknown Chip found, Chip %04x Revision %x\n", + chip_type, chip_rev); + return -ENODEV; + } + + rc = superio_enter(); + if (rc) + return rc; + + superio_select(GPIO); + + /* fetch GPIO base address */ + it87_gpio->io_base = superio_inw(gpio_ba_reg); + + superio_exit(); + + pr_info("Found Chip IT%04x rev %x. %u GPIO lines starting at %04xh\n", + chip_type, chip_rev, it87_gpio->chip.ngpio, + it87_gpio->io_base); + + if (!request_region(it87_gpio->io_base, it87_gpio->io_size, + KBUILD_MODNAME)) + return -EBUSY; + + /* Set up aliases for the GPIO connection. + * + * ITE documentation for recent chips such as the IT8728F + * refers to the GPIO lines as GPxy, with a coordinates system + * where x is the GPIO group (starting from 1) and y is the + * bit within the group. + * + * By creating these aliases, we make it easier to understand + * to which GPIO pin we're referring to. + */ + labels = kcalloc(it87_gpio->chip.ngpio, sizeof("it87_gpXY"), + GFP_KERNEL); + labels_table = kcalloc(it87_gpio->chip.ngpio, sizeof(const char *), + GFP_KERNEL); + + if (!labels || !labels_table) { + rc = -ENOMEM; + goto labels_free; + } + + for (i = 0; i < it87_gpio->chip.ngpio; i++) { + char *label = &labels[i * sizeof("it87_gpXY")]; + + sprintf(label, "it87_gp%u%u", 1+(i/8), i%8); + labels_table[i] = label; + } + + it87_gpio->chip.names = (const char *const*)labels_table; + + rc = gpiochip_add_data(&it87_gpio->chip, it87_gpio); + if (rc) + goto labels_free; + + return 0; + +labels_free: + kfree(labels_table); + kfree(labels); + release_region(it87_gpio->io_base, it87_gpio->io_size); + return rc; +} + +static void __exit it87_gpio_exit(void) +{ + struct it87_gpio *it87_gpio = &it87_gpio_chip; + + gpiochip_remove(&it87_gpio->chip); + release_region(it87_gpio->io_base, it87_gpio->io_size); + kfree(it87_gpio->chip.names[0]); + kfree(it87_gpio->chip.names); +} + +module_init(it87_gpio_init); +module_exit(it87_gpio_exit); + +MODULE_AUTHOR("Diego Elio Pettenò <flameeyes@flameeyes.eu>"); +MODULE_DESCRIPTION("GPIO interface for IT87xx Super I/O chips"); +MODULE_LICENSE("GPL"); |