/* * Generic Syscon LEDs Driver * * Copyright (c) 2014, Linaro Limited * Author: Linus Walleij <linus.walleij@linaro.org> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * 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; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ #include <linux/io.h> #include <linux/init.h> #include <linux/of_device.h> #include <linux/of_address.h> #include <linux/platform_device.h> #include <linux/stat.h> #include <linux/slab.h> #include <linux/mfd/syscon.h> #include <linux/regmap.h> #include <linux/leds.h> /** * struct syscon_led - state container for syscon based LEDs * @cdev: LED class device for this LED * @map: regmap to access the syscon device backing this LED * @offset: the offset into the syscon regmap for the LED register * @mask: the bit in the register corresponding to the LED * @state: current state of the LED */ struct syscon_led { struct led_classdev cdev; struct regmap *map; u32 offset; u32 mask; bool state; }; static void syscon_led_set(struct led_classdev *led_cdev, enum led_brightness value) { struct syscon_led *sled = container_of(led_cdev, struct syscon_led, cdev); u32 val; int ret; if (value == LED_OFF) { val = 0; sled->state = false; } else { val = sled->mask; sled->state = true; } ret = regmap_update_bits(sled->map, sled->offset, sled->mask, val); if (ret < 0) dev_err(sled->cdev.dev, "error updating LED status\n"); } static int syscon_led_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; struct device *parent; struct regmap *map; struct syscon_led *sled; const char *state; int ret; parent = dev->parent; if (!parent) { dev_err(dev, "no parent for syscon LED\n"); return -ENODEV; } map = syscon_node_to_regmap(parent->of_node); if (IS_ERR(map)) { dev_err(dev, "no regmap for syscon LED parent\n"); return PTR_ERR(map); } sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL); if (!sled) return -ENOMEM; sled->map = map; if (of_property_read_u32(np, "offset", &sled->offset)) return -EINVAL; if (of_property_read_u32(np, "mask", &sled->mask)) return -EINVAL; sled->cdev.name = of_get_property(np, "label", NULL) ? : np->name; sled->cdev.default_trigger = of_get_property(np, "linux,default-trigger", NULL); state = of_get_property(np, "default-state", NULL); if (state) { if (!strcmp(state, "keep")) { u32 val; ret = regmap_read(map, sled->offset, &val); if (ret < 0) return ret; sled->state = !!(val & sled->mask); } else if (!strcmp(state, "on")) { sled->state = true; ret = regmap_update_bits(map, sled->offset, sled->mask, sled->mask); if (ret < 0) return ret; } else { sled->state = false; ret = regmap_update_bits(map, sled->offset, sled->mask, 0); if (ret < 0) return ret; } } sled->cdev.brightness_set = syscon_led_set; ret = led_classdev_register(dev, &sled->cdev); if (ret < 0) return ret; platform_set_drvdata(pdev, sled); dev_info(dev, "registered LED %s\n", sled->cdev.name); return 0; } static const struct of_device_id of_syscon_leds_match[] = { { .compatible = "register-bit-led", }, {}, }; static struct platform_driver syscon_led_driver = { .probe = syscon_led_probe, .driver = { .name = "leds-syscon", .of_match_table = of_syscon_leds_match, .suppress_bind_attrs = true, }, }; builtin_platform_driver(syscon_led_driver);