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/err.h> 14 #include <linux/gpio.h> 15 #include <linux/gpio/consumer.h> 16 #include <linux/kernel.h> 17 #include <linux/leds.h> 18 #include <linux/module.h> 19 #include <linux/platform_device.h> 20 #include <linux/property.h> 21 #include <linux/slab.h> 22 #include <linux/workqueue.h> 23 24 struct gpio_led_data { 25 struct led_classdev cdev; 26 struct gpio_desc *gpiod; 27 struct work_struct work; 28 u8 new_level; 29 u8 can_sleep; 30 u8 blinking; 31 int (*platform_gpio_blink_set)(struct gpio_desc *desc, int state, 32 unsigned long *delay_on, unsigned long *delay_off); 33 }; 34 35 static void gpio_led_work(struct work_struct *work) 36 { 37 struct gpio_led_data *led_dat = 38 container_of(work, struct gpio_led_data, work); 39 40 if (led_dat->blinking) { 41 led_dat->platform_gpio_blink_set(led_dat->gpiod, 42 led_dat->new_level, NULL, NULL); 43 led_dat->blinking = 0; 44 } else 45 gpiod_set_value_cansleep(led_dat->gpiod, led_dat->new_level); 46 } 47 48 static void gpio_led_set(struct led_classdev *led_cdev, 49 enum led_brightness value) 50 { 51 struct gpio_led_data *led_dat = 52 container_of(led_cdev, struct gpio_led_data, cdev); 53 int level; 54 55 if (value == LED_OFF) 56 level = 0; 57 else 58 level = 1; 59 60 /* Setting GPIOs with I2C/etc requires a task context, and we don't 61 * seem to have a reliable way to know if we're already in one; so 62 * let's just assume the worst. 63 */ 64 if (led_dat->can_sleep) { 65 led_dat->new_level = level; 66 schedule_work(&led_dat->work); 67 } else { 68 if (led_dat->blinking) { 69 led_dat->platform_gpio_blink_set(led_dat->gpiod, level, 70 NULL, NULL); 71 led_dat->blinking = 0; 72 } else 73 gpiod_set_value(led_dat->gpiod, level); 74 } 75 } 76 77 static int gpio_blink_set(struct led_classdev *led_cdev, 78 unsigned long *delay_on, unsigned long *delay_off) 79 { 80 struct gpio_led_data *led_dat = 81 container_of(led_cdev, struct gpio_led_data, cdev); 82 83 led_dat->blinking = 1; 84 return led_dat->platform_gpio_blink_set(led_dat->gpiod, GPIO_LED_BLINK, 85 delay_on, delay_off); 86 } 87 88 static int create_gpio_led(const struct gpio_led *template, 89 struct gpio_led_data *led_dat, struct device *parent, 90 int (*blink_set)(struct gpio_desc *, int, unsigned long *, 91 unsigned long *)) 92 { 93 int ret, state; 94 95 led_dat->gpiod = template->gpiod; 96 if (!led_dat->gpiod) { 97 /* 98 * This is the legacy code path for platform code that 99 * still uses GPIO numbers. Ultimately we would like to get 100 * rid of this block completely. 101 */ 102 unsigned long flags = 0; 103 104 /* skip leds that aren't available */ 105 if (!gpio_is_valid(template->gpio)) { 106 dev_info(parent, "Skipping unavailable LED gpio %d (%s)\n", 107 template->gpio, template->name); 108 return 0; 109 } 110 111 if (template->active_low) 112 flags |= GPIOF_ACTIVE_LOW; 113 114 ret = devm_gpio_request_one(parent, template->gpio, flags, 115 template->name); 116 if (ret < 0) 117 return ret; 118 119 led_dat->gpiod = gpio_to_desc(template->gpio); 120 if (IS_ERR(led_dat->gpiod)) 121 return PTR_ERR(led_dat->gpiod); 122 } 123 124 led_dat->cdev.name = template->name; 125 led_dat->cdev.default_trigger = template->default_trigger; 126 led_dat->can_sleep = gpiod_cansleep(led_dat->gpiod); 127 led_dat->blinking = 0; 128 if (blink_set) { 129 led_dat->platform_gpio_blink_set = blink_set; 130 led_dat->cdev.blink_set = gpio_blink_set; 131 } 132 led_dat->cdev.brightness_set = gpio_led_set; 133 if (template->default_state == LEDS_GPIO_DEFSTATE_KEEP) 134 state = !!gpiod_get_value_cansleep(led_dat->gpiod); 135 else 136 state = (template->default_state == LEDS_GPIO_DEFSTATE_ON); 137 led_dat->cdev.brightness = state ? LED_FULL : LED_OFF; 138 if (!template->retain_state_suspended) 139 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; 140 141 ret = gpiod_direction_output(led_dat->gpiod, state); 142 if (ret < 0) 143 return ret; 144 145 INIT_WORK(&led_dat->work, gpio_led_work); 146 147 return led_classdev_register(parent, &led_dat->cdev); 148 } 149 150 static void delete_gpio_led(struct gpio_led_data *led) 151 { 152 led_classdev_unregister(&led->cdev); 153 cancel_work_sync(&led->work); 154 } 155 156 struct gpio_leds_priv { 157 int num_leds; 158 struct gpio_led_data leds[]; 159 }; 160 161 static inline int sizeof_gpio_leds_priv(int num_leds) 162 { 163 return sizeof(struct gpio_leds_priv) + 164 (sizeof(struct gpio_led_data) * num_leds); 165 } 166 167 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev) 168 { 169 struct device *dev = &pdev->dev; 170 struct fwnode_handle *child; 171 struct gpio_leds_priv *priv; 172 int count, ret; 173 struct device_node *np; 174 175 count = device_get_child_node_count(dev); 176 if (!count) 177 return ERR_PTR(-ENODEV); 178 179 priv = devm_kzalloc(dev, sizeof_gpio_leds_priv(count), GFP_KERNEL); 180 if (!priv) 181 return ERR_PTR(-ENOMEM); 182 183 device_for_each_child_node(dev, child) { 184 struct gpio_led led = {}; 185 const char *state = NULL; 186 187 led.gpiod = devm_get_gpiod_from_child(dev, child); 188 if (IS_ERR(led.gpiod)) { 189 fwnode_handle_put(child); 190 ret = PTR_ERR(led.gpiod); 191 goto err; 192 } 193 194 np = of_node(child); 195 196 if (fwnode_property_present(child, "label")) { 197 fwnode_property_read_string(child, "label", &led.name); 198 } else { 199 if (IS_ENABLED(CONFIG_OF) && !led.name && np) 200 led.name = np->name; 201 if (!led.name) 202 return ERR_PTR(-EINVAL); 203 } 204 fwnode_property_read_string(child, "linux,default-trigger", 205 &led.default_trigger); 206 207 if (!fwnode_property_read_string(child, "default-state", 208 &state)) { 209 if (!strcmp(state, "keep")) 210 led.default_state = LEDS_GPIO_DEFSTATE_KEEP; 211 else if (!strcmp(state, "on")) 212 led.default_state = LEDS_GPIO_DEFSTATE_ON; 213 else 214 led.default_state = LEDS_GPIO_DEFSTATE_OFF; 215 } 216 217 if (fwnode_property_present(child, "retain-state-suspended")) 218 led.retain_state_suspended = 1; 219 220 ret = create_gpio_led(&led, &priv->leds[priv->num_leds++], 221 dev, NULL); 222 if (ret < 0) { 223 fwnode_handle_put(child); 224 goto err; 225 } 226 } 227 228 return priv; 229 230 err: 231 for (count = priv->num_leds - 2; count >= 0; count--) 232 delete_gpio_led(&priv->leds[count]); 233 return ERR_PTR(ret); 234 } 235 236 static const struct of_device_id of_gpio_leds_match[] = { 237 { .compatible = "gpio-leds", }, 238 {}, 239 }; 240 241 MODULE_DEVICE_TABLE(of, of_gpio_leds_match); 242 243 static int gpio_led_probe(struct platform_device *pdev) 244 { 245 struct gpio_led_platform_data *pdata = dev_get_platdata(&pdev->dev); 246 struct gpio_leds_priv *priv; 247 int i, ret = 0; 248 249 if (pdata && pdata->num_leds) { 250 priv = devm_kzalloc(&pdev->dev, 251 sizeof_gpio_leds_priv(pdata->num_leds), 252 GFP_KERNEL); 253 if (!priv) 254 return -ENOMEM; 255 256 priv->num_leds = pdata->num_leds; 257 for (i = 0; i < priv->num_leds; i++) { 258 ret = create_gpio_led(&pdata->leds[i], 259 &priv->leds[i], 260 &pdev->dev, pdata->gpio_blink_set); 261 if (ret < 0) { 262 /* On failure: unwind the led creations */ 263 for (i = i - 1; i >= 0; i--) 264 delete_gpio_led(&priv->leds[i]); 265 return ret; 266 } 267 } 268 } else { 269 priv = gpio_leds_create(pdev); 270 if (IS_ERR(priv)) 271 return PTR_ERR(priv); 272 } 273 274 platform_set_drvdata(pdev, priv); 275 276 return 0; 277 } 278 279 static int gpio_led_remove(struct platform_device *pdev) 280 { 281 struct gpio_leds_priv *priv = platform_get_drvdata(pdev); 282 int i; 283 284 for (i = 0; i < priv->num_leds; i++) 285 delete_gpio_led(&priv->leds[i]); 286 287 return 0; 288 } 289 290 static struct platform_driver gpio_led_driver = { 291 .probe = gpio_led_probe, 292 .remove = gpio_led_remove, 293 .driver = { 294 .name = "leds-gpio", 295 .of_match_table = of_gpio_leds_match, 296 }, 297 }; 298 299 module_platform_driver(gpio_led_driver); 300 301 MODULE_AUTHOR("Raphael Assenat <raph@8d.com>, Trent Piepho <tpiepho@freescale.com>"); 302 MODULE_DESCRIPTION("GPIO LED driver"); 303 MODULE_LICENSE("GPL"); 304 MODULE_ALIAS("platform:leds-gpio"); 305