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![Linus Walleij](/assets/img/avatar_default.png)
Currently the syscon LED driver will only handle LEDs on the first syscon found in the system. But there can be several of them, so augment the driver to traverse all syscon nodes and check for syscon LEDs on them. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Bryan Wu <cooloney@gmail.com>
167 lines
4.2 KiB
C
167 lines
4.2 KiB
C
/*
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* Generic Syscon LEDs Driver
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*
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* Copyright (c) 2014, Linaro Limited
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* Author: Linus Walleij <linus.walleij@linaro.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <linux/io.h>
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#include <linux/of_device.h>
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#include <linux/of_address.h>
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#include <linux/platform_device.h>
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#include <linux/stat.h>
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#include <linux/slab.h>
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#include <linux/mfd/syscon.h>
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#include <linux/regmap.h>
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#include <linux/leds.h>
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/**
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* struct syscon_led - state container for syscon based LEDs
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* @cdev: LED class device for this LED
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* @map: regmap to access the syscon device backing this LED
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* @offset: the offset into the syscon regmap for the LED register
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* @mask: the bit in the register corresponding to the LED
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* @state: current state of the LED
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*/
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struct syscon_led {
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struct led_classdev cdev;
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struct regmap *map;
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u32 offset;
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u32 mask;
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bool state;
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};
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static void syscon_led_set(struct led_classdev *led_cdev,
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enum led_brightness value)
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{
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struct syscon_led *sled =
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container_of(led_cdev, struct syscon_led, cdev);
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u32 val;
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int ret;
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if (value == LED_OFF) {
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val = 0;
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sled->state = false;
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} else {
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val = sled->mask;
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sled->state = true;
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}
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ret = regmap_update_bits(sled->map, sled->offset, sled->mask, val);
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if (ret < 0)
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dev_err(sled->cdev.dev, "error updating LED status\n");
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}
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static int __init syscon_leds_spawn(struct device_node *np,
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struct device *dev,
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struct regmap *map)
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{
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struct device_node *child;
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int ret;
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for_each_available_child_of_node(np, child) {
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struct syscon_led *sled;
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const char *state;
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/* Only check for register-bit-leds */
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if (of_property_match_string(child, "compatible",
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"register-bit-led") < 0)
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continue;
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sled = devm_kzalloc(dev, sizeof(*sled), GFP_KERNEL);
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if (!sled)
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return -ENOMEM;
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sled->map = map;
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if (of_property_read_u32(child, "offset", &sled->offset))
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return -EINVAL;
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if (of_property_read_u32(child, "mask", &sled->mask))
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return -EINVAL;
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sled->cdev.name =
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of_get_property(child, "label", NULL) ? : child->name;
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sled->cdev.default_trigger =
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of_get_property(child, "linux,default-trigger", NULL);
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state = of_get_property(child, "default-state", NULL);
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if (state) {
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if (!strcmp(state, "keep")) {
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u32 val;
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ret = regmap_read(map, sled->offset, &val);
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if (ret < 0)
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return ret;
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sled->state = !!(val & sled->mask);
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} else if (!strcmp(state, "on")) {
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sled->state = true;
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ret = regmap_update_bits(map, sled->offset,
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sled->mask,
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sled->mask);
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if (ret < 0)
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return ret;
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} else {
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sled->state = false;
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ret = regmap_update_bits(map, sled->offset,
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sled->mask, 0);
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if (ret < 0)
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return ret;
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}
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}
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sled->cdev.brightness_set = syscon_led_set;
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ret = led_classdev_register(dev, &sled->cdev);
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if (ret < 0)
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return ret;
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dev_info(dev, "registered LED %s\n", sled->cdev.name);
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}
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return 0;
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}
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static int __init syscon_leds_init(void)
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{
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struct device_node *np;
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for_each_of_allnodes(np) {
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struct platform_device *pdev;
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struct regmap *map;
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int ret;
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if (!of_device_is_compatible(np, "syscon"))
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continue;
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map = syscon_node_to_regmap(np);
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if (IS_ERR(map)) {
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pr_err("error getting regmap for syscon LEDs\n");
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continue;
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}
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/*
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* If the map is there, the device should be there, we allocate
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* memory on the syscon device's behalf here.
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*/
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pdev = of_find_device_by_node(np);
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if (!pdev)
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return -ENODEV;
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ret = syscon_leds_spawn(np, &pdev->dev, map);
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if (ret)
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dev_err(&pdev->dev, "could not spawn syscon LEDs\n");
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}
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return 0;
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}
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device_initcall(syscon_leds_init);
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