diff options
Diffstat (limited to 'kernel/drivers/leds/leds-syscon.c')
| -rw-r--r-- | kernel/drivers/leds/leds-syscon.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/kernel/drivers/leds/leds-syscon.c b/kernel/drivers/leds/leds-syscon.c new file mode 100644 index 000000000..6896e2d9b --- /dev/null +++ b/kernel/drivers/leds/leds-syscon.c @@ -0,0 +1,167 @@ +/* + * 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/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 __init syscon_leds_spawn(struct device_node *np, + struct device *dev, + struct regmap *map) +{ + struct device_node *child; + int ret; + + for_each_available_child_of_node(np, child) { + struct syscon_led *sled; + const char *state; + + /* Only check for register-bit-leds */ + if (of_property_match_string(child, "compatible", + "register-bit-led") < 0) + continue; + + sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL); + if (!sled) + return -ENOMEM; + + sled->map = map; + + if (of_property_read_u32(child, "offset", &sled->offset)) + return -EINVAL; + if (of_property_read_u32(child, "mask", &sled->mask)) + return -EINVAL; + sled->cdev.name = + of_get_property(child, "label", NULL) ? : child->name; + sled->cdev.default_trigger = + of_get_property(child, "linux,default-trigger", NULL); + + state = of_get_property(child, "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; + + dev_info(dev, "registered LED %s\n", sled->cdev.name); + } + return 0; +} + +static int __init syscon_leds_init(void) +{ + struct device_node *np; + + for_each_of_allnodes(np) { + struct platform_device *pdev; + struct regmap *map; + int ret; + + if (!of_device_is_compatible(np, "syscon")) + continue; + + map = syscon_node_to_regmap(np); + if (IS_ERR(map)) { + pr_err("error getting regmap for syscon LEDs\n"); + continue; + } + + /* + * If the map is there, the device should be there, we allocate + * memory on the syscon device's behalf here. + */ + pdev = of_find_device_by_node(np); + if (!pdev) + return -ENODEV; + ret = syscon_leds_spawn(np, &pdev->dev, map); + if (ret) + dev_err(&pdev->dev, "could not spawn syscon LEDs\n"); + } + + return 0; +} +device_initcall(syscon_leds_init); |