1 /* 2 * LEDs driver for GPIOs 3 * 4 * Copyright (C) 2007 8D Technologies inc. 5 * Raphael Assenat <raph@8d.com> 6 * Copyright (C) 2008 Freescale Semiconductor, Inc. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 */ 13 #include <linux/kernel.h> 14 #include <linux/init.h> 15 #include <linux/platform_device.h> 16 #include <linux/gpio.h> 17 #include <linux/leds.h> 18 #include <linux/of_platform.h> 19 #include <linux/of_gpio.h> 20 #include <linux/slab.h> 21 #include <linux/workqueue.h> 22 #include <linux/module.h> 23 #include <linux/err.h> 24 25 struct gpio_led_data { 26 struct led_classdev cdev; 27 unsigned gpio; 28 struct work_struct work; 29 u8 new_level; 30 u8 can_sleep; 31 u8 active_low; 32 u8 blinking; 33 int (*platform_gpio_blink_set)(unsigned gpio, int state, 34 unsigned long *delay_on, unsigned long *delay_off); 35 }; 36 37 static void gpio_led_work(struct work_struct *work) 38 { 39 struct gpio_led_data *led_dat = 40 container_of(work, struct gpio_led_data, work); 41 42 if (led_dat->blinking) { 43 led_dat->platform_gpio_blink_set(led_dat->gpio, 44 led_dat->new_level, 45 NULL, NULL); 46 led_dat->blinking = 0; 47 } else 48 gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level); 49 } 50 51 static void gpio_led_set(struct led_classdev *led_cdev, 52 enum led_brightness value) 53 { 54 struct gpio_led_data *led_dat = 55 container_of(led_cdev, struct gpio_led_data, cdev); 56 int level; 57 58 if (value == LED_OFF) 59 level = 0; 60 else 61 level = 1; 62 63 if (led_dat->active_low) 64 level = !level; 65 66 /* Setting GPIOs with I2C/etc requires a task context, and we don't 67 * seem to have a reliable way to know if we're already in one; so 68 * let's just assume the worst. 69 */ 70 if (led_dat->can_sleep) { 71 led_dat->new_level = level; 72 schedule_work(&led_dat->work); 73 } else { 74 if (led_dat->blinking) { 75 led_dat->platform_gpio_blink_set(led_dat->gpio, level, 76 NULL, NULL); 77 led_dat->blinking = 0; 78 } else 79 gpio_set_value(led_dat->gpio, level); 80 } 81 } 82 83 static int gpio_blink_set(struct led_classdev *led_cdev, 84 unsigned long *delay_on, unsigned long *delay_off) 85 { 86 struct gpio_led_data *led_dat = 87 container_of(led_cdev, struct gpio_led_data, cdev); 88 89 led_dat->blinking = 1; 90 return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK, 91 delay_on, delay_off); 92 } 93 94 static int create_gpio_led(const struct gpio_led *template, 95 struct gpio_led_data *led_dat, struct device *parent, 96 int (*blink_set)(unsigned, int, unsigned long *, unsigned long *)) 97 { 98 int ret, state; 99 100 led_dat->gpio = -1; 101 102 /* skip leds that aren't available */ 103 if (!gpio_is_valid(template->gpio)) { 104 dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n", 105 template->gpio, template->name); 106 return 0; 107 } 108 109 ret = devm_gpio_request(parent, template->gpio, template->name); 110 if (ret < 0) 111 return ret; 112 113 led_dat->cdev.name = template->name; 114 led_dat->cdev.default_trigger = template->default_trigger; 115 led_dat->gpio = template->gpio; 116 led_dat->can_sleep = gpio_cansleep(template->gpio); 117 led_dat->active_low = template->active_low; 118 led_dat->blinking = 0; 119 if (blink_set) { 120 led_dat->platform_gpio_blink_set = blink_set; 121 led_dat->cdev.blink_set = gpio_blink_set; 122 } 123 led_dat->cdev.brightness_set = gpio_led_set; 124 if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) 125 state = !!gpio_get_value_cansleep(led_dat->gpio) ^ led_dat->active_low; 126 else 127 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON); 128 led_dat->cdev.brightness = state ? LED_FULL : LED_OFF; 129 if (!template->retain_state_suspended) 130 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; 131 132 ret = gpio_direction_output(led_dat->gpio, led_dat->active_low ^ state); 133 if (ret < 0) 134 return ret; 135 136 INIT_WORK(&led_dat->work, gpio_led_work); 137 138 ret = led_classdev_register(parent, &led_dat->cdev); 139 if (ret < 0) 140 return ret; 141 142 return 0; 143 } 144 145 static void delete_gpio_led(struct gpio_led_data *led) 146 { 147 if (!gpio_is_valid(led->gpio)) 148 return; 149 led_classdev_unregister(&led->cdev); 150 cancel_work_sync(&led->work); 151 } 152 153 struct gpio_leds_priv { 154 int num_leds; 155 struct gpio_led_data leds[]; 156 }; 157 158 static inline int sizeof_gpio_leds_priv(int num_leds) 159 { 160 return sizeof(struct gpio_leds_priv) + 161 (sizeof(struct gpio_led_data) * num_leds); 162 } 163 164 /* Code to create from OpenFirmware platform devices */ 165 #ifdef CONFIG_OF_GPIO 166 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev) 167 { 168 struct device_node *np = pdev->dev.of_node, *child; 169 struct gpio_leds_priv *priv; 170 int count, ret; 171 172 /* count LEDs in this device, so we know how much to allocate */ 173 count = of_get_child_count(np); 174 if (!count) 175 return ERR_PTR(-ENODEV); 176 177 for_each_child_of_node(np, child) 178 if (of_get_gpio(child, 0) == -EPROBE_DEFER) 179 return ERR_PTR(-EPROBE_DEFER); 180 181 priv = devm_kzalloc(&pdev->dev, sizeof_gpio_leds_priv(count), 182 GFP_KERNEL); 183 if (!priv) 184 return ERR_PTR(-ENOMEM); 185 186 for_each_child_of_node(np, child) { 187 struct gpio_led led = {}; 188 enum of_gpio_flags flags; 189 const char *state; 190 191 led.gpio = of_get_gpio_flags(child, 0, &flags); 192 led.active_low = flags & OF_GPIO_ACTIVE_LOW; 193 led.name = of_get_property(child, "label", NULL) ? : child->name; 194 led.default_trigger = 195 of_get_property(child, "linux,default-trigger", NULL); 196 state = of_get_property(child, "default-state", NULL); 197 if (state) { 198 if (!strcmp(state, "keep")) 199 led.default_state = LEDS_GPIO_DEFSTATE_KEEP; 200 else if (!strcmp(state, "on")) 201 led.default_state = LEDS_GPIO_DEFSTATE_ON; 202 else 203 led.default_state = LEDS_GPIO_DEFSTATE_OFF; 204 } 205 206 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++], 207 &pdev->dev, NULL); 208 if (ret < 0) { 209 of_node_put(child); 210 goto err; 211 } 212 } 213 214 return priv; 215 216 err: 217 for (count = priv->num_leds - 2; count >= 0; count--) 218 delete_gpio_led(&priv->leds[count]); 219 return ERR_PTR(-ENODEV); 220 } 221 222 static const struct of_device_id of_gpio_leds_match[] = { 223 { .compatible = "gpio-leds", }, 224 {}, 225 }; 226 #else /* CONFIG_OF_GPIO */ 227 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev) 228 { 229 return ERR_PTR(-ENODEV); 230 } 231 #endif /* CONFIG_OF_GPIO */ 232 233 234 static int gpio_led_probe(struct platform_device *pdev) 235 { 236 struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev); 237 struct gpio_leds_priv *priv; 238 int i, ret = 0; 239 240 241 if (pdata && pdata->num_leds) { 242 priv = devm_kzalloc(&pdev->dev, 243 sizeof_gpio_leds_priv(pdata->num_leds), 244 GFP_KERNEL); 245 if (!priv) 246 return -ENOMEM; 247 248 priv->num_leds = pdata->num_leds; 249 for (i = 0; i < priv->num_leds; i++) { 250 ret = create_gpio_led(&pdata->leds[i], 251 &priv->leds[i], 252 &pdev->dev, pdata->gpio_blink_set); 253 if (ret < 0) { 254 /* On failure: unwind the led creations */ 255 for (i = i - 1; i >= 0; i--) 256 delete_gpio_led(&priv->leds[i]); 257 return ret; 258 } 259 } 260 } else { 261 priv = gpio_leds_create_of(pdev); 262 if (IS_ERR(priv)) 263 return PTR_ERR(priv); 264 } 265 266 platform_set_drvdata(pdev, priv); 267 268 return 0; 269 } 270 271 static int gpio_led_remove(struct platform_device *pdev) 272 { 273 struct gpio_leds_priv *priv = platform_get_drvdata(pdev); 274 int i; 275 276 for (i = 0; i < priv->num_leds; i++) 277 delete_gpio_led(&priv->leds[i]); 278 279 return 0; 280 } 281 282 static struct platform_driver gpio_led_driver = { 283 .probe = gpio_led_probe, 284 .remove = gpio_led_remove, 285 .driver = { 286 .name = "leds-gpio", 287 .owner = THIS_MODULE, 288 .of_match_table = of_match_ptr(of_gpio_leds_match), 289 }, 290 }; 291 292 module_platform_driver(gpio_led_driver); 293 294 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>"); 295 MODULE_DESCRIPTION("GPIO LED driver"); 296 MODULE_LICENSE("GPL"); 297 MODULE_ALIAS("platform:leds-gpio"); 298