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/pinctrl/consumer.h> 24 #include <linux/err.h> 25 26 struct gpio_led_data { 27 struct led_classdev cdev; 28 unsigned gpio; 29 struct work_struct work; 30 u8 new_level; 31 u8 can_sleep; 32 u8 active_low; 33 u8 blinking; 34 int (*platform_gpio_blink_set)(unsigned gpio, int state, 35 unsigned long *delay_on, unsigned long *delay_off); 36 }; 37 38 static void gpio_led_work(struct work_struct *work) 39 { 40 struct gpio_led_data *led_dat = 41 container_of(work, struct gpio_led_data, work); 42 43 if (led_dat->blinking) { 44 led_dat->platform_gpio_blink_set(led_dat->gpio, 45 led_dat->new_level, 46 NULL, NULL); 47 led_dat->blinking = 0; 48 } else 49 gpio_set_value_cansleep(led_dat->gpio, led_dat->new_level); 50 } 51 52 static void gpio_led_set(struct led_classdev *led_cdev, 53 enum led_brightness value) 54 { 55 struct gpio_led_data *led_dat = 56 container_of(led_cdev, struct gpio_led_data, cdev); 57 int level; 58 59 if (value == LED_OFF) 60 level = 0; 61 else 62 level = 1; 63 64 if (led_dat->active_low) 65 level = !level; 66 67 /* Setting GPIOs with I2C/etc requires a task context, and we don't 68 * seem to have a reliable way to know if we're already in one; so 69 * let's just assume the worst. 70 */ 71 if (led_dat->can_sleep) { 72 led_dat->new_level = level; 73 schedule_work(&led_dat->work); 74 } else { 75 if (led_dat->blinking) { 76 led_dat->platform_gpio_blink_set(led_dat->gpio, level, 77 NULL, NULL); 78 led_dat->blinking = 0; 79 } else 80 gpio_set_value(led_dat->gpio, level); 81 } 82 } 83 84 static int gpio_blink_set(struct led_classdev *led_cdev, 85 unsigned long *delay_on, unsigned long *delay_off) 86 { 87 struct gpio_led_data *led_dat = 88 container_of(led_cdev, struct gpio_led_data, cdev); 89 90 led_dat->blinking = 1; 91 return led_dat->platform_gpio_blink_set(led_dat->gpio, GPIO_LED_BLINK, 92 delay_on, delay_off); 93 } 94 95 static int create_gpio_led(const struct gpio_led *template, 96 struct gpio_led_data *led_dat, struct device *parent, 97 int (*blink_set)(unsigned, int, unsigned long *, unsigned long *)) 98 { 99 int ret, state; 100 101 led_dat->gpio = -1; 102 103 /* skip leds that aren't available */ 104 if (!gpio_is_valid(template->gpio)) { 105 dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n", 106 template->gpio, template->name); 107 return 0; 108 } 109 110 led_dat->cdev.name = template->name; 111 led_dat->cdev.default_trigger = template->default_trigger; 112 led_dat->gpio = template->gpio; 113 led_dat->can_sleep = gpio_cansleep(template->gpio); 114 led_dat->active_low = template->active_low; 115 led_dat->blinking = 0; 116 if (blink_set) { 117 led_dat->platform_gpio_blink_set = blink_set; 118 led_dat->cdev.blink_set = gpio_blink_set; 119 } 120 led_dat->cdev.brightness_set = gpio_led_set; 121 if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) 122 state = !!gpio_get_value_cansleep(led_dat->gpio) ^ led_dat->active_low; 123 else 124 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON); 125 led_dat->cdev.brightness = state ? LED_FULL : LED_OFF; 126 if (!template->retain_state_suspended) 127 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; 128 129 ret = devm_gpio_request_one(parent, template->gpio, 130 GPIOF_DIR_OUT | (led_dat->active_low ^ state), 131 template->name); 132 if (ret < 0) 133 return ret; 134 135 INIT_WORK(&led_dat->work, gpio_led_work); 136 137 ret = led_classdev_register(parent, &led_dat->cdev); 138 if (ret < 0) 139 return ret; 140 141 return 0; 142 } 143 144 static void delete_gpio_led(struct gpio_led_data *led) 145 { 146 if (!gpio_is_valid(led->gpio)) 147 return; 148 led_classdev_unregister(&led->cdev); 149 cancel_work_sync(&led->work); 150 } 151 152 struct gpio_leds_priv { 153 int num_leds; 154 struct gpio_led_data leds[]; 155 }; 156 157 static inline int sizeof_gpio_leds_priv(int num_leds) 158 { 159 return sizeof(struct gpio_leds_priv) + 160 (sizeof(struct gpio_led_data) * num_leds); 161 } 162 163 /* Code to create from OpenFirmware platform devices */ 164 #ifdef CONFIG_OF_GPIO 165 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev) 166 { 167 struct device_node *np = pdev->dev.of_node, *child; 168 struct gpio_leds_priv *priv; 169 int count, ret; 170 171 /* count LEDs in this device, so we know how much to allocate */ 172 count = of_get_child_count(np); 173 if (!count) 174 return ERR_PTR(-ENODEV); 175 176 for_each_child_of_node(np, child) 177 if (of_get_gpio(child, 0) == -EPROBE_DEFER) 178 return ERR_PTR(-EPROBE_DEFER); 179 180 priv = devm_kzalloc(&pdev->dev, sizeof_gpio_leds_priv(count), 181 GFP_KERNEL); 182 if (!priv) 183 return ERR_PTR(-ENOMEM); 184 185 for_each_child_of_node(np, child) { 186 struct gpio_led led = {}; 187 enum of_gpio_flags flags; 188 const char *state; 189 190 led.gpio = of_get_gpio_flags(child, 0, &flags); 191 led.active_low = flags & OF_GPIO_ACTIVE_LOW; 192 led.name = of_get_property(child, "label", NULL) ? : child->name; 193 led.default_trigger = 194 of_get_property(child, "linux,default-trigger", NULL); 195 state = of_get_property(child, "default-state", NULL); 196 if (state) { 197 if (!strcmp(state, "keep")) 198 led.default_state = LEDS_GPIO_DEFSTATE_KEEP; 199 else if (!strcmp(state, "on")) 200 led.default_state = LEDS_GPIO_DEFSTATE_ON; 201 else 202 led.default_state = LEDS_GPIO_DEFSTATE_OFF; 203 } 204 205 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++], 206 &pdev->dev, NULL); 207 if (ret < 0) { 208 of_node_put(child); 209 goto err; 210 } 211 } 212 213 return priv; 214 215 err: 216 for (count = priv->num_leds - 2; count >= 0; count--) 217 delete_gpio_led(&priv->leds[count]); 218 return ERR_PTR(-ENODEV); 219 } 220 221 static const struct of_device_id of_gpio_leds_match[] = { 222 { .compatible = "gpio-leds", }, 223 {}, 224 }; 225 #else /* CONFIG_OF_GPIO */ 226 static struct gpio_leds_priv *gpio_leds_create_of(struct platform_device *pdev) 227 { 228 return ERR_PTR(-ENODEV); 229 } 230 #endif /* CONFIG_OF_GPIO */ 231 232 233 static int gpio_led_probe(struct platform_device *pdev) 234 { 235 struct gpio_led_platform_data *pdata = pdev->dev.platform_data; 236 struct gpio_leds_priv *priv; 237 struct pinctrl *pinctrl; 238 int i, ret = 0; 239 240 pinctrl = devm_pinctrl_get_select_default(&pdev->dev); 241 if (IS_ERR(pinctrl)) 242 dev_warn(&pdev->dev, 243 "pins are not configured from the driver\n"); 244 245 if (pdata && pdata->num_leds) { 246 priv = devm_kzalloc(&pdev->dev, 247 sizeof_gpio_leds_priv(pdata->num_leds), 248 GFP_KERNEL); 249 if (!priv) 250 return -ENOMEM; 251 252 priv->num_leds = pdata->num_leds; 253 for (i = 0; i < priv->num_leds; i++) { 254 ret = create_gpio_led(&pdata->leds[i], 255 &priv->leds[i], 256 &pdev->dev, pdata->gpio_blink_set); 257 if (ret < 0) { 258 /* On failure: unwind the led creations */ 259 for (i = i - 1; i >= 0; i--) 260 delete_gpio_led(&priv->leds[i]); 261 return ret; 262 } 263 } 264 } else { 265 priv = gpio_leds_create_of(pdev); 266 if (IS_ERR(priv)) 267 return PTR_ERR(priv); 268 } 269 270 platform_set_drvdata(pdev, priv); 271 272 return 0; 273 } 274 275 static int gpio_led_remove(struct platform_device *pdev) 276 { 277 struct gpio_leds_priv *priv = platform_get_drvdata(pdev); 278 int i; 279 280 for (i = 0; i < priv->num_leds; i++) 281 delete_gpio_led(&priv->leds[i]); 282 283 platform_set_drvdata(pdev, NULL); 284 285 return 0; 286 } 287 288 static struct platform_driver gpio_led_driver = { 289 .probe = gpio_led_probe, 290 .remove = gpio_led_remove, 291 .driver = { 292 .name = "leds-gpio", 293 .owner = THIS_MODULE, 294 .of_match_table = of_match_ptr(of_gpio_leds_match), 295 }, 296 }; 297 298 module_platform_driver(gpio_led_driver); 299 300 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>"); 301 MODULE_DESCRIPTION("GPIO LED driver"); 302 MODULE_LICENSE("GPL"); 303 MODULE_ALIAS("platform:leds-gpio"); 304