| 1 | /* |
| 2 | * linux/drivers/leds-pwm.c |
| 3 | * |
| 4 | * simple PWM based LED control |
| 5 | * |
| 6 | * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de) |
| 7 | * |
| 8 | * based on leds-gpio.c by Raphael Assenat <raph@8d.com> |
| 9 | * |
| 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. |
| 13 | */ |
| 14 | |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/platform_device.h> |
| 18 | #include <linux/of_platform.h> |
| 19 | #include <linux/fb.h> |
| 20 | #include <linux/leds.h> |
| 21 | #include <linux/err.h> |
| 22 | #include <linux/pwm.h> |
| 23 | #include <linux/leds_pwm.h> |
| 24 | #include <linux/slab.h> |
| 25 | |
| 26 | struct led_pwm_data { |
| 27 | struct led_classdev cdev; |
| 28 | struct pwm_device *pwm; |
| 29 | unsigned int active_low; |
| 30 | unsigned int period; |
| 31 | int duty; |
| 32 | bool can_sleep; |
| 33 | }; |
| 34 | |
| 35 | struct led_pwm_priv { |
| 36 | int num_leds; |
| 37 | struct led_pwm_data leds[0]; |
| 38 | }; |
| 39 | |
| 40 | static void __led_pwm_set(struct led_pwm_data *led_dat) |
| 41 | { |
| 42 | int new_duty = led_dat->duty; |
| 43 | |
| 44 | pwm_config(led_dat->pwm, new_duty, led_dat->period); |
| 45 | |
| 46 | if (new_duty == 0) |
| 47 | pwm_disable(led_dat->pwm); |
| 48 | else |
| 49 | pwm_enable(led_dat->pwm); |
| 50 | } |
| 51 | |
| 52 | static void led_pwm_set(struct led_classdev *led_cdev, |
| 53 | enum led_brightness brightness) |
| 54 | { |
| 55 | struct led_pwm_data *led_dat = |
| 56 | container_of(led_cdev, struct led_pwm_data, cdev); |
| 57 | unsigned int max = led_dat->cdev.max_brightness; |
| 58 | unsigned long long duty = led_dat->period; |
| 59 | |
| 60 | duty *= brightness; |
| 61 | do_div(duty, max); |
| 62 | |
| 63 | if (led_dat->active_low) |
| 64 | duty = led_dat->period - duty; |
| 65 | |
| 66 | led_dat->duty = duty; |
| 67 | |
| 68 | __led_pwm_set(led_dat); |
| 69 | } |
| 70 | |
| 71 | static int led_pwm_set_blocking(struct led_classdev *led_cdev, |
| 72 | enum led_brightness brightness) |
| 73 | { |
| 74 | led_pwm_set(led_cdev, brightness); |
| 75 | return 0; |
| 76 | } |
| 77 | |
| 78 | static inline size_t sizeof_pwm_leds_priv(int num_leds) |
| 79 | { |
| 80 | return sizeof(struct led_pwm_priv) + |
| 81 | (sizeof(struct led_pwm_data) * num_leds); |
| 82 | } |
| 83 | |
| 84 | static void led_pwm_cleanup(struct led_pwm_priv *priv) |
| 85 | { |
| 86 | while (priv->num_leds--) |
| 87 | led_classdev_unregister(&priv->leds[priv->num_leds].cdev); |
| 88 | } |
| 89 | |
| 90 | static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv, |
| 91 | struct led_pwm *led, struct device_node *child) |
| 92 | { |
| 93 | struct led_pwm_data *led_data = &priv->leds[priv->num_leds]; |
| 94 | int ret; |
| 95 | |
| 96 | led_data->active_low = led->active_low; |
| 97 | led_data->cdev.name = led->name; |
| 98 | led_data->cdev.default_trigger = led->default_trigger; |
| 99 | led_data->cdev.brightness = LED_OFF; |
| 100 | led_data->cdev.max_brightness = led->max_brightness; |
| 101 | led_data->cdev.flags = LED_CORE_SUSPENDRESUME; |
| 102 | |
| 103 | if (child) |
| 104 | led_data->pwm = devm_of_pwm_get(dev, child, NULL); |
| 105 | else |
| 106 | led_data->pwm = devm_pwm_get(dev, led->name); |
| 107 | if (IS_ERR(led_data->pwm)) { |
| 108 | ret = PTR_ERR(led_data->pwm); |
| 109 | dev_err(dev, "unable to request PWM for %s: %d\n", |
| 110 | led->name, ret); |
| 111 | return ret; |
| 112 | } |
| 113 | |
| 114 | led_data->can_sleep = pwm_can_sleep(led_data->pwm); |
| 115 | if (!led_data->can_sleep) |
| 116 | led_data->cdev.brightness_set = led_pwm_set; |
| 117 | else |
| 118 | led_data->cdev.brightness_set_blocking = led_pwm_set_blocking; |
| 119 | |
| 120 | led_data->period = pwm_get_period(led_data->pwm); |
| 121 | if (!led_data->period && (led->pwm_period_ns > 0)) |
| 122 | led_data->period = led->pwm_period_ns; |
| 123 | |
| 124 | ret = led_classdev_register(dev, &led_data->cdev); |
| 125 | if (ret == 0) { |
| 126 | priv->num_leds++; |
| 127 | led_pwm_set(&led_data->cdev, led_data->cdev.brightness); |
| 128 | } else { |
| 129 | dev_err(dev, "failed to register PWM led for %s: %d\n", |
| 130 | led->name, ret); |
| 131 | } |
| 132 | |
| 133 | return ret; |
| 134 | } |
| 135 | |
| 136 | static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv) |
| 137 | { |
| 138 | struct device_node *child; |
| 139 | struct led_pwm led; |
| 140 | int ret = 0; |
| 141 | |
| 142 | memset(&led, 0, sizeof(led)); |
| 143 | |
| 144 | for_each_child_of_node(dev->of_node, child) { |
| 145 | led.name = of_get_property(child, "label", NULL) ? : |
| 146 | child->name; |
| 147 | |
| 148 | led.default_trigger = of_get_property(child, |
| 149 | "linux,default-trigger", NULL); |
| 150 | led.active_low = of_property_read_bool(child, "active-low"); |
| 151 | of_property_read_u32(child, "max-brightness", |
| 152 | &led.max_brightness); |
| 153 | |
| 154 | ret = led_pwm_add(dev, priv, &led, child); |
| 155 | if (ret) { |
| 156 | of_node_put(child); |
| 157 | break; |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | return ret; |
| 162 | } |
| 163 | |
| 164 | static int led_pwm_probe(struct platform_device *pdev) |
| 165 | { |
| 166 | struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev); |
| 167 | struct led_pwm_priv *priv; |
| 168 | int count, i; |
| 169 | int ret = 0; |
| 170 | |
| 171 | if (pdata) |
| 172 | count = pdata->num_leds; |
| 173 | else |
| 174 | count = of_get_child_count(pdev->dev.of_node); |
| 175 | |
| 176 | if (!count) |
| 177 | return -EINVAL; |
| 178 | |
| 179 | priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count), |
| 180 | GFP_KERNEL); |
| 181 | if (!priv) |
| 182 | return -ENOMEM; |
| 183 | |
| 184 | if (pdata) { |
| 185 | for (i = 0; i < count; i++) { |
| 186 | ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i], |
| 187 | NULL); |
| 188 | if (ret) |
| 189 | break; |
| 190 | } |
| 191 | } else { |
| 192 | ret = led_pwm_create_of(&pdev->dev, priv); |
| 193 | } |
| 194 | |
| 195 | if (ret) { |
| 196 | led_pwm_cleanup(priv); |
| 197 | return ret; |
| 198 | } |
| 199 | |
| 200 | platform_set_drvdata(pdev, priv); |
| 201 | |
| 202 | return 0; |
| 203 | } |
| 204 | |
| 205 | static int led_pwm_remove(struct platform_device *pdev) |
| 206 | { |
| 207 | struct led_pwm_priv *priv = platform_get_drvdata(pdev); |
| 208 | |
| 209 | led_pwm_cleanup(priv); |
| 210 | |
| 211 | return 0; |
| 212 | } |
| 213 | |
| 214 | static const struct of_device_id of_pwm_leds_match[] = { |
| 215 | { .compatible = "pwm-leds", }, |
| 216 | {}, |
| 217 | }; |
| 218 | MODULE_DEVICE_TABLE(of, of_pwm_leds_match); |
| 219 | |
| 220 | static struct platform_driver led_pwm_driver = { |
| 221 | .probe = led_pwm_probe, |
| 222 | .remove = led_pwm_remove, |
| 223 | .driver = { |
| 224 | .name = "leds_pwm", |
| 225 | .of_match_table = of_pwm_leds_match, |
| 226 | }, |
| 227 | }; |
| 228 | |
| 229 | module_platform_driver(led_pwm_driver); |
| 230 | |
| 231 | MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>"); |
| 232 | MODULE_DESCRIPTION("generic PWM LED driver"); |
| 233 | MODULE_LICENSE("GPL v2"); |
| 234 | MODULE_ALIAS("platform:leds-pwm"); |