2 * linux/drivers/leds-pwm.c
4 * simple PWM based LED control
6 * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
8 * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/platform_device.h>
19 #include <linux/of_platform.h>
21 #include <linux/leds.h>
22 #include <linux/err.h>
23 #include <linux/pwm.h>
24 #include <linux/leds_pwm.h>
25 #include <linux/slab.h>
26 #include <linux/workqueue.h>
29 struct led_classdev cdev
;
30 struct pwm_device
*pwm
;
31 struct work_struct work
;
32 unsigned int active_low
;
40 struct led_pwm_data leds
[0];
43 static void __led_pwm_set(struct led_pwm_data
*led_dat
)
45 int new_duty
= led_dat
->duty
;
47 pwm_config(led_dat
->pwm
, new_duty
, led_dat
->period
);
50 pwm_disable(led_dat
->pwm
);
52 pwm_enable(led_dat
->pwm
);
55 static void led_pwm_work(struct work_struct
*work
)
57 struct led_pwm_data
*led_dat
=
58 container_of(work
, struct led_pwm_data
, work
);
60 __led_pwm_set(led_dat
);
63 static void led_pwm_set(struct led_classdev
*led_cdev
,
64 enum led_brightness brightness
)
66 struct led_pwm_data
*led_dat
=
67 container_of(led_cdev
, struct led_pwm_data
, cdev
);
68 unsigned int max
= led_dat
->cdev
.max_brightness
;
69 unsigned int period
= led_dat
->period
;
71 led_dat
->duty
= brightness
* period
/ max
;
73 if (led_dat
->can_sleep
)
74 schedule_work(&led_dat
->work
);
76 __led_pwm_set(led_dat
);
79 static inline size_t sizeof_pwm_leds_priv(int num_leds
)
81 return sizeof(struct led_pwm_priv
) +
82 (sizeof(struct led_pwm_data
) * num_leds
);
85 static struct led_pwm_priv
*led_pwm_create_of(struct platform_device
*pdev
)
87 struct device_node
*node
= pdev
->dev
.of_node
;
88 struct device_node
*child
;
89 struct led_pwm_priv
*priv
;
92 /* count LEDs in this device, so we know how much to allocate */
93 count
= of_get_child_count(node
);
97 priv
= devm_kzalloc(&pdev
->dev
, sizeof_pwm_leds_priv(count
),
102 for_each_child_of_node(node
, child
) {
103 struct led_pwm_data
*led_dat
= &priv
->leds
[priv
->num_leds
];
105 led_dat
->cdev
.name
= of_get_property(child
, "label",
106 NULL
) ? : child
->name
;
108 led_dat
->pwm
= devm_of_pwm_get(&pdev
->dev
, child
, NULL
);
109 if (IS_ERR(led_dat
->pwm
)) {
110 dev_err(&pdev
->dev
, "unable to request PWM for %s\n",
114 /* Get the period from PWM core when n*/
115 led_dat
->period
= pwm_get_period(led_dat
->pwm
);
117 led_dat
->cdev
.default_trigger
= of_get_property(child
,
118 "linux,default-trigger", NULL
);
119 of_property_read_u32(child
, "max-brightness",
120 &led_dat
->cdev
.max_brightness
);
122 led_dat
->cdev
.brightness_set
= led_pwm_set
;
123 led_dat
->cdev
.brightness
= LED_OFF
;
124 led_dat
->cdev
.flags
|= LED_CORE_SUSPENDRESUME
;
126 led_dat
->can_sleep
= pwm_can_sleep(led_dat
->pwm
);
127 if (led_dat
->can_sleep
)
128 INIT_WORK(&led_dat
->work
, led_pwm_work
);
130 ret
= led_classdev_register(&pdev
->dev
, &led_dat
->cdev
);
132 dev_err(&pdev
->dev
, "failed to register for %s\n",
142 while (priv
->num_leds
--)
143 led_classdev_unregister(&priv
->leds
[priv
->num_leds
].cdev
);
148 static int led_pwm_probe(struct platform_device
*pdev
)
150 struct led_pwm_platform_data
*pdata
= dev_get_platdata(&pdev
->dev
);
151 struct led_pwm_priv
*priv
;
154 if (pdata
&& pdata
->num_leds
) {
155 priv
= devm_kzalloc(&pdev
->dev
,
156 sizeof_pwm_leds_priv(pdata
->num_leds
),
161 for (i
= 0; i
< pdata
->num_leds
; i
++) {
162 struct led_pwm
*cur_led
= &pdata
->leds
[i
];
163 struct led_pwm_data
*led_dat
= &priv
->leds
[i
];
165 led_dat
->pwm
= devm_pwm_get(&pdev
->dev
, cur_led
->name
);
166 if (IS_ERR(led_dat
->pwm
)) {
167 ret
= PTR_ERR(led_dat
->pwm
);
169 "unable to request PWM for %s\n",
174 led_dat
->cdev
.name
= cur_led
->name
;
175 led_dat
->cdev
.default_trigger
= cur_led
->default_trigger
;
176 led_dat
->active_low
= cur_led
->active_low
;
177 led_dat
->period
= cur_led
->pwm_period_ns
;
178 led_dat
->cdev
.brightness_set
= led_pwm_set
;
179 led_dat
->cdev
.brightness
= LED_OFF
;
180 led_dat
->cdev
.max_brightness
= cur_led
->max_brightness
;
181 led_dat
->cdev
.flags
|= LED_CORE_SUSPENDRESUME
;
183 led_dat
->can_sleep
= pwm_can_sleep(led_dat
->pwm
);
184 if (led_dat
->can_sleep
)
185 INIT_WORK(&led_dat
->work
, led_pwm_work
);
187 ret
= led_classdev_register(&pdev
->dev
, &led_dat
->cdev
);
191 priv
->num_leds
= pdata
->num_leds
;
193 priv
= led_pwm_create_of(pdev
);
198 platform_set_drvdata(pdev
, priv
);
204 led_classdev_unregister(&priv
->leds
[i
].cdev
);
209 static int led_pwm_remove(struct platform_device
*pdev
)
211 struct led_pwm_priv
*priv
= platform_get_drvdata(pdev
);
214 for (i
= 0; i
< priv
->num_leds
; i
++) {
215 led_classdev_unregister(&priv
->leds
[i
].cdev
);
216 if (priv
->leds
[i
].can_sleep
)
217 cancel_work_sync(&priv
->leds
[i
].work
);
223 static const struct of_device_id of_pwm_leds_match
[] = {
224 { .compatible
= "pwm-leds", },
227 MODULE_DEVICE_TABLE(of
, of_pwm_leds_match
);
229 static struct platform_driver led_pwm_driver
= {
230 .probe
= led_pwm_probe
,
231 .remove
= led_pwm_remove
,
234 .owner
= THIS_MODULE
,
235 .of_match_table
= of_match_ptr(of_pwm_leds_match
),
239 module_platform_driver(led_pwm_driver
);
241 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
242 MODULE_DESCRIPTION("PWM LED driver for PXA");
243 MODULE_LICENSE("GPL");
244 MODULE_ALIAS("platform:leds-pwm");