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1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org>
3
4#include <linux/kernel.h>
5#include <linux/platform_device.h>
6#include <linux/leds.h>
7#include <linux/delay.h>
8#include <linux/gpio/consumer.h>
9#include <linux/slab.h>
10#include <linux/mod_devicetable.h>
11#include <linux/module.h>
12#include <linux/property.h>
13
14#define LED_LT3593_NAME "lt3593"
15
16struct lt3593_led_data {
17 struct led_classdev cdev;
18 struct gpio_desc *gpiod;
19};
20
21static int lt3593_led_set(struct led_classdev *led_cdev,
22 enum led_brightness value)
23{
24 struct lt3593_led_data *led_dat =
25 container_of(led_cdev, struct lt3593_led_data, cdev);
26 int pulses;
27
28 /*
29 * The LT3593 resets its internal current level register to the maximum
30 * level on the first falling edge on the control pin. Each following
31 * falling edge decreases the current level by 625uA. Up to 32 pulses
32 * can be sent, so the maximum power reduction is 20mA.
33 * After a timeout of 128us, the value is taken from the register and
34 * applied is to the output driver.
35 */
36
37 if (value == 0) {
38 gpiod_set_value_cansleep(led_dat->gpiod, 0);
39 return 0;
40 }
41
42 pulses = 32 - (value * 32) / 255;
43
44 if (pulses == 0) {
45 gpiod_set_value_cansleep(led_dat->gpiod, 0);
46 mdelay(1);
47 gpiod_set_value_cansleep(led_dat->gpiod, 1);
48 return 0;
49 }
50
51 gpiod_set_value_cansleep(led_dat->gpiod, 1);
52
53 while (pulses--) {
54 gpiod_set_value_cansleep(led_dat->gpiod, 0);
55 udelay(1);
56 gpiod_set_value_cansleep(led_dat->gpiod, 1);
57 udelay(1);
58 }
59
60 return 0;
61}
62
63static int lt3593_led_probe(struct platform_device *pdev)
64{
65 struct device *dev = &pdev->dev;
66 struct lt3593_led_data *led_data;
67 struct fwnode_handle *child;
68 int ret, state = LEDS_GPIO_DEFSTATE_OFF;
69 struct led_init_data init_data = {};
70 const char *tmp;
71
72 led_data = devm_kzalloc(dev, sizeof(*led_data), GFP_KERNEL);
73 if (!led_data)
74 return -ENOMEM;
75
76 if (device_get_child_node_count(dev) != 1) {
77 dev_err(dev, "Device must have exactly one LED sub-node.");
78 return -EINVAL;
79 }
80
81 led_data->gpiod = devm_gpiod_get(dev, "lltc,ctrl", 0);
82 if (IS_ERR(led_data->gpiod))
83 return PTR_ERR(led_data->gpiod);
84
85 child = device_get_next_child_node(dev, NULL);
86
87 if (!fwnode_property_read_string(child, "default-state", &tmp)) {
88 if (!strcmp(tmp, "on"))
89 state = LEDS_GPIO_DEFSTATE_ON;
90 }
91
92 led_data->cdev.brightness_set_blocking = lt3593_led_set;
93 led_data->cdev.brightness = state ? LED_FULL : LED_OFF;
94
95 init_data.fwnode = child;
96 init_data.devicename = LED_LT3593_NAME;
97 init_data.default_label = ":";
98
99 ret = devm_led_classdev_register_ext(dev, &led_data->cdev, &init_data);
100 fwnode_handle_put(child);
101 if (ret < 0)
102 return ret;
103
104 platform_set_drvdata(pdev, led_data);
105
106 return 0;
107}
108
109static const struct of_device_id of_lt3593_leds_match[] = {
110 { .compatible = "lltc,lt3593", },
111 {},
112};
113MODULE_DEVICE_TABLE(of, of_lt3593_leds_match);
114
115static struct platform_driver lt3593_led_driver = {
116 .probe = lt3593_led_probe,
117 .driver = {
118 .name = "leds-lt3593",
119 .of_match_table = of_lt3593_leds_match,
120 },
121};
122
123module_platform_driver(lt3593_led_driver);
124
125MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
126MODULE_DESCRIPTION("LED driver for LT3593 controllers");
127MODULE_LICENSE("GPL v2");
128MODULE_ALIAS("platform:leds-lt3593");
1/*
2 * LEDs driver for LT3593 controllers
3 *
4 * See the datasheet at http://cds.linear.com/docs/Datasheet/3593f.pdf
5 *
6 * Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
7 *
8 * Based on leds-gpio.c,
9 *
10 * Copyright (C) 2007 8D Technologies inc.
11 * Raphael Assenat <raph@8d.com>
12 * Copyright (C) 2008 Freescale Semiconductor, Inc.
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License version 2 as
16 * published by the Free Software Foundation.
17 */
18
19#include <linux/kernel.h>
20#include <linux/platform_device.h>
21#include <linux/leds.h>
22#include <linux/workqueue.h>
23#include <linux/delay.h>
24#include <linux/gpio.h>
25#include <linux/slab.h>
26#include <linux/module.h>
27
28struct lt3593_led_data {
29 struct led_classdev cdev;
30 unsigned gpio;
31 struct work_struct work;
32 u8 new_level;
33};
34
35static void lt3593_led_work(struct work_struct *work)
36{
37 int pulses;
38 struct lt3593_led_data *led_dat =
39 container_of(work, struct lt3593_led_data, work);
40
41 /*
42 * The LT3593 resets its internal current level register to the maximum
43 * level on the first falling edge on the control pin. Each following
44 * falling edge decreases the current level by 625uA. Up to 32 pulses
45 * can be sent, so the maximum power reduction is 20mA.
46 * After a timeout of 128us, the value is taken from the register and
47 * applied is to the output driver.
48 */
49
50 if (led_dat->new_level == 0) {
51 gpio_set_value_cansleep(led_dat->gpio, 0);
52 return;
53 }
54
55 pulses = 32 - (led_dat->new_level * 32) / 255;
56
57 if (pulses == 0) {
58 gpio_set_value_cansleep(led_dat->gpio, 0);
59 mdelay(1);
60 gpio_set_value_cansleep(led_dat->gpio, 1);
61 return;
62 }
63
64 gpio_set_value_cansleep(led_dat->gpio, 1);
65
66 while (pulses--) {
67 gpio_set_value_cansleep(led_dat->gpio, 0);
68 udelay(1);
69 gpio_set_value_cansleep(led_dat->gpio, 1);
70 udelay(1);
71 }
72}
73
74static void lt3593_led_set(struct led_classdev *led_cdev,
75 enum led_brightness value)
76{
77 struct lt3593_led_data *led_dat =
78 container_of(led_cdev, struct lt3593_led_data, cdev);
79
80 led_dat->new_level = value;
81 schedule_work(&led_dat->work);
82}
83
84static int create_lt3593_led(const struct gpio_led *template,
85 struct lt3593_led_data *led_dat, struct device *parent)
86{
87 int ret, state;
88
89 /* skip leds on GPIOs that aren't available */
90 if (!gpio_is_valid(template->gpio)) {
91 dev_info(parent, "%s: skipping unavailable LT3593 LED at gpio %d (%s)\n",
92 KBUILD_MODNAME, template->gpio, template->name);
93 return 0;
94 }
95
96 led_dat->cdev.name = template->name;
97 led_dat->cdev.default_trigger = template->default_trigger;
98 led_dat->gpio = template->gpio;
99
100 led_dat->cdev.brightness_set = lt3593_led_set;
101
102 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON);
103 led_dat->cdev.brightness = state ? LED_FULL : LED_OFF;
104
105 if (!template->retain_state_suspended)
106 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
107
108 ret = devm_gpio_request_one(parent, template->gpio, state ?
109 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
110 template->name);
111 if (ret < 0)
112 return ret;
113
114 INIT_WORK(&led_dat->work, lt3593_led_work);
115
116 ret = led_classdev_register(parent, &led_dat->cdev);
117 if (ret < 0)
118 return ret;
119
120 dev_info(parent, "%s: registered LT3593 LED '%s' at GPIO %d\n",
121 KBUILD_MODNAME, template->name, template->gpio);
122
123 return 0;
124}
125
126static void delete_lt3593_led(struct lt3593_led_data *led)
127{
128 if (!gpio_is_valid(led->gpio))
129 return;
130
131 led_classdev_unregister(&led->cdev);
132 cancel_work_sync(&led->work);
133}
134
135static int lt3593_led_probe(struct platform_device *pdev)
136{
137 struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
138 struct lt3593_led_data *leds_data;
139 int i, ret = 0;
140
141 if (!pdata)
142 return -EBUSY;
143
144 leds_data = devm_kzalloc(&pdev->dev,
145 sizeof(struct lt3593_led_data) * pdata->num_leds,
146 GFP_KERNEL);
147 if (!leds_data)
148 return -ENOMEM;
149
150 for (i = 0; i < pdata->num_leds; i++) {
151 ret = create_lt3593_led(&pdata->leds[i], &leds_data[i],
152 &pdev->dev);
153 if (ret < 0)
154 goto err;
155 }
156
157 platform_set_drvdata(pdev, leds_data);
158
159 return 0;
160
161err:
162 for (i = i - 1; i >= 0; i--)
163 delete_lt3593_led(&leds_data[i]);
164
165 return ret;
166}
167
168static int lt3593_led_remove(struct platform_device *pdev)
169{
170 int i;
171 struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev);
172 struct lt3593_led_data *leds_data;
173
174 leds_data = platform_get_drvdata(pdev);
175
176 for (i = 0; i < pdata->num_leds; i++)
177 delete_lt3593_led(&leds_data[i]);
178
179 return 0;
180}
181
182static struct platform_driver lt3593_led_driver = {
183 .probe = lt3593_led_probe,
184 .remove = lt3593_led_remove,
185 .driver = {
186 .name = "leds-lt3593",
187 .owner = THIS_MODULE,
188 },
189};
190
191module_platform_driver(lt3593_led_driver);
192
193MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
194MODULE_DESCRIPTION("LED driver for LT3593 controllers");
195MODULE_LICENSE("GPL");
196MODULE_ALIAS("platform:leds-lt3593");