156 lines
3.9 KiB
C
156 lines
3.9 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/init.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 syscon_led_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct device_node *np = dev->of_node;
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struct device *parent;
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struct regmap *map;
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struct syscon_led *sled;
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const char *state;
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int ret;
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parent = dev->parent;
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if (!parent) {
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dev_err(dev, "no parent for syscon LED\n");
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return -ENODEV;
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}
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map = syscon_node_to_regmap(parent->of_node);
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if (IS_ERR(map)) {
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dev_err(dev, "no regmap for syscon LED parent\n");
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return PTR_ERR(map);
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}
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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(np, "offset", &sled->offset))
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return -EINVAL;
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if (of_property_read_u32(np, "mask", &sled->mask))
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return -EINVAL;
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sled->cdev.name =
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of_get_property(np, "label", NULL) ? : np->name;
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sled->cdev.default_trigger =
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of_get_property(np, "linux,default-trigger", NULL);
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state = of_get_property(np, "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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platform_set_drvdata(pdev, sled);
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dev_info(dev, "registered LED %s\n", sled->cdev.name);
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return 0;
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}
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static const struct of_device_id of_syscon_leds_match[] = {
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{ .compatible = "register-bit-led", },
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{},
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};
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static struct platform_driver syscon_led_driver = {
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.probe = syscon_led_probe,
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.driver = {
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.name = "leds-syscon",
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.of_match_table = of_syscon_leds_match,
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.suppress_bind_attrs = true,
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},
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};
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builtin_platform_driver(syscon_led_driver);
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