// SPDX-License-Identifier: GPL-2.0-or-later /* * portwell-ec.c: Portwell embedded controller driver. * * Tested on: * - Portwell NANO-6064 * * This driver provides support for GPIO and Watchdog Timer * functionalities of the Portwell boards with ITE embedded controller (EC). * The EC is accessed through I/O ports and provides: * - 8 GPIO pins for control and monitoring * - Hardware watchdog with 1-15300 second timeout range * * It integrates with the Linux GPIO and Watchdog subsystems, allowing * userspace interaction with EC GPIO pins and watchdog control, * ensuring system stability and configurability. * * (C) Copyright 2025 Portwell, Inc. * Author: Yen-Chi Huang (jesse.huang@portwell.com.tw) */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #define PORTWELL_EC_IOSPACE 0xe300 #define PORTWELL_EC_IOSPACE_LEN SZ_256 #define PORTWELL_GPIO_PINS 8 #define PORTWELL_GPIO_DIR_REG 0x2b #define PORTWELL_GPIO_VAL_REG 0x2c #define PORTWELL_WDT_EC_CONFIG_ADDR 0x06 #define PORTWELL_WDT_CONFIG_ENABLE 0x1 #define PORTWELL_WDT_CONFIG_DISABLE 0x0 #define PORTWELL_WDT_EC_COUNT_MIN_ADDR 0x07 #define PORTWELL_WDT_EC_COUNT_SEC_ADDR 0x08 #define PORTWELL_WDT_EC_MAX_COUNT_SECOND (255 * 60) #define PORTWELL_EC_FW_VENDOR_ADDRESS 0x4d #define PORTWELL_EC_FW_VENDOR_LENGTH 3 #define PORTWELL_EC_FW_VENDOR_NAME "PWG" static bool force; module_param(force, bool, 0444); MODULE_PARM_DESC(force, "Force loading EC driver without checking DMI boardname"); static const struct dmi_system_id pwec_dmi_table[] = { { .ident = "NANO-6064 series", .matches = { DMI_MATCH(DMI_BOARD_NAME, "NANO-6064"), }, }, { } }; MODULE_DEVICE_TABLE(dmi, pwec_dmi_table); /* Functions for access EC via IOSPACE */ static void pwec_write(u8 index, u8 data) { outb(data, PORTWELL_EC_IOSPACE + index); } static u8 pwec_read(u8 address) { return inb(PORTWELL_EC_IOSPACE + address); } /* GPIO functions */ static int pwec_gpio_get(struct gpio_chip *chip, unsigned int offset) { return pwec_read(PORTWELL_GPIO_VAL_REG) & BIT(offset) ? 1 : 0; } static int pwec_gpio_set_rv(struct gpio_chip *chip, unsigned int offset, int val) { u8 tmp = pwec_read(PORTWELL_GPIO_VAL_REG); if (val) tmp |= BIT(offset); else tmp &= ~BIT(offset); pwec_write(PORTWELL_GPIO_VAL_REG, tmp); return 0; } static int pwec_gpio_get_direction(struct gpio_chip *chip, unsigned int offset) { u8 direction = pwec_read(PORTWELL_GPIO_DIR_REG) & BIT(offset); if (direction) return GPIO_LINE_DIRECTION_IN; return GPIO_LINE_DIRECTION_OUT; } /* * Changing direction causes issues on some boards, * so direction_input and direction_output are disabled for now. */ static int pwec_gpio_direction_input(struct gpio_chip *gc, unsigned int offset) { return -EOPNOTSUPP; } static int pwec_gpio_direction_output(struct gpio_chip *gc, unsigned int offset, int value) { return -EOPNOTSUPP; } static struct gpio_chip pwec_gpio_chip = { .label = "portwell-ec-gpio", .get_direction = pwec_gpio_get_direction, .direction_input = pwec_gpio_direction_input, .direction_output = pwec_gpio_direction_output, .get = pwec_gpio_get, .set_rv = pwec_gpio_set_rv, .base = -1, .ngpio = PORTWELL_GPIO_PINS, }; /* Watchdog functions */ static void pwec_wdt_write_timeout(unsigned int timeout) { pwec_write(PORTWELL_WDT_EC_COUNT_MIN_ADDR, timeout / 60); pwec_write(PORTWELL_WDT_EC_COUNT_SEC_ADDR, timeout % 60); } static int pwec_wdt_trigger(struct watchdog_device *wdd) { pwec_wdt_write_timeout(wdd->timeout); pwec_write(PORTWELL_WDT_EC_CONFIG_ADDR, PORTWELL_WDT_CONFIG_ENABLE); return 0; } static int pwec_wdt_start(struct watchdog_device *wdd) { return pwec_wdt_trigger(wdd); } static int pwec_wdt_stop(struct watchdog_device *wdd) { pwec_write(PORTWELL_WDT_EC_CONFIG_ADDR, PORTWELL_WDT_CONFIG_DISABLE); return 0; } static int pwec_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout) { wdd->timeout = timeout; pwec_wdt_write_timeout(wdd->timeout); return 0; } /* Ensure consistent min/sec read in case of second rollover. */ static unsigned int pwec_wdt_get_timeleft(struct watchdog_device *wdd) { u8 sec, min, old_min; do { old_min = pwec_read(PORTWELL_WDT_EC_COUNT_MIN_ADDR); sec = pwec_read(PORTWELL_WDT_EC_COUNT_SEC_ADDR); min = pwec_read(PORTWELL_WDT_EC_COUNT_MIN_ADDR); } while (min != old_min); return min * 60 + sec; } static const struct watchdog_ops pwec_wdt_ops = { .owner = THIS_MODULE, .start = pwec_wdt_start, .stop = pwec_wdt_stop, .ping = pwec_wdt_trigger, .set_timeout = pwec_wdt_set_timeout, .get_timeleft = pwec_wdt_get_timeleft, }; static struct watchdog_device ec_wdt_dev = { .info = &(struct watchdog_info){ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .identity = "Portwell EC watchdog", }, .ops = &pwec_wdt_ops, .timeout = 60, .min_timeout = 1, .max_timeout = PORTWELL_WDT_EC_MAX_COUNT_SECOND, }; static int pwec_firmware_vendor_check(void) { u8 buf[PORTWELL_EC_FW_VENDOR_LENGTH + 1]; u8 i; for (i = 0; i < PORTWELL_EC_FW_VENDOR_LENGTH; i++) buf[i] = pwec_read(PORTWELL_EC_FW_VENDOR_ADDRESS + i); buf[PORTWELL_EC_FW_VENDOR_LENGTH] = '\0'; return !strcmp(PORTWELL_EC_FW_VENDOR_NAME, buf) ? 0 : -ENODEV; } static int pwec_probe(struct platform_device *pdev) { int ret; if (!devm_request_region(&pdev->dev, PORTWELL_EC_IOSPACE, PORTWELL_EC_IOSPACE_LEN, dev_name(&pdev->dev))) { dev_err(&pdev->dev, "failed to get IO region\n"); return -EBUSY; } ret = pwec_firmware_vendor_check(); if (ret < 0) return ret; ret = devm_gpiochip_add_data(&pdev->dev, &pwec_gpio_chip, NULL); if (ret < 0) { dev_err(&pdev->dev, "failed to register Portwell EC GPIO\n"); return ret; } ret = devm_watchdog_register_device(&pdev->dev, &ec_wdt_dev); if (ret < 0) { dev_err(&pdev->dev, "failed to register Portwell EC Watchdog\n"); return ret; } return 0; } static struct platform_driver pwec_driver = { .driver = { .name = "portwell-ec", }, .probe = pwec_probe, }; static struct platform_device *pwec_dev; static int __init pwec_init(void) { int ret; if (!dmi_check_system(pwec_dmi_table)) { if (!force) return -ENODEV; pr_warn("force load portwell-ec without DMI check\n"); } ret = platform_driver_register(&pwec_driver); if (ret) return ret; pwec_dev = platform_device_register_simple("portwell-ec", -1, NULL, 0); if (IS_ERR(pwec_dev)) { platform_driver_unregister(&pwec_driver); return PTR_ERR(pwec_dev); } return 0; } static void __exit pwec_exit(void) { platform_device_unregister(pwec_dev); platform_driver_unregister(&pwec_driver); } module_init(pwec_init); module_exit(pwec_exit); MODULE_AUTHOR("Yen-Chi Huang "); MODULE_DESCRIPTION("Portwell EC Driver"); MODULE_LICENSE("GPL");