target/linux/ar71xx/files/drivers/leds/leds-nu801.c

   1 /*
   2  * LED driver for NU801
   3  *
   4  * Kevin Paul Herbert
   5  * Copyright (c) 2012, Meraki, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/leds.h>
  19 #include <linux/workqueue.h>
  20 #include <linux/delay.h>
  21 #include <linux/leds-nu801.h>
  22
  23 #include <asm/gpio.h>
  24 #include <linux/of_gpio.h>
  25
  26 #define MAX_NAME_LENGTH 24
  27 #define NUM_COLORS 3
  28
  29 static const char * const led_nu801_colors[] = { "blue", "green", "red" };
  30
  31 struct led_nu801_led_data {
  32         struct led_classdev cdev;
  33         struct led_nu801_data *controller;
  34         enum led_brightness level;
  35         char name[MAX_NAME_LENGTH];
  36 };
  37
  38 struct led_nu801_data {
  39         unsigned cki;
  40         unsigned sdi;
  41         int lei;
  42         struct delayed_work work;
  43         struct led_nu801_led_data *led_chain;
  44         int num_leds;
  45         const char *device_name;
  46         const char *name;
  47         u32 ndelay;
  48         atomic_t pending;
  49 };
  50
  51 static void led_nu801_work(struct work_struct *work)
  52 {
  53         struct led_nu801_data   *controller =
  54                 container_of(work, struct led_nu801_data, work.work);
  55         struct led_nu801_led_data *led;
  56         u16 bit;
  57         u16 brightness;
  58         int index;
  59
  60         for (index = 0; index < controller->num_leds; index++) {
  61                 led = &controller->led_chain[index];
  62                 brightness = led->level << 8; /* To do: gamma correction */
  63                 for (bit = 0x8000; bit; bit = bit >> 1) {
  64                         gpio_set_value(controller->sdi,
  65                                        (brightness & bit) != 0);
  66                         gpio_set_value(controller->cki, 1);
  67                         if (unlikely(((index == (controller->num_leds - 1)) &&
  68                                       (bit == 1) &&
  69                                       (controller->lei < 0)))) {
  70                                 udelay(600);
  71                         } else {
  72                                 ndelay(controller->ndelay);
  73                         }
  74                         gpio_set_value(controller->cki, 0);
  75                         ndelay(controller->ndelay);
  76                 }
  77         }
  78         if (controller->lei >= 0) {
  79                 gpio_set_value(controller->lei, 1);
  80                 ndelay(controller->ndelay);
  81                 gpio_set_value(controller->lei, 0);
  82         }
  83         atomic_set(&controller->pending, 1);
  84 }
  85
  86 static void led_nu801_set(struct led_classdev *led_cdev,
  87                           enum led_brightness value)
  88 {
  89         struct led_nu801_led_data *led_dat =
  90                 container_of(led_cdev, struct led_nu801_led_data, cdev);
  91         struct led_nu801_data *controller = led_dat->controller;
  92
  93         if (led_dat->level != value) {
  94                 led_dat->level = value;
  95                 if (atomic_dec_and_test(&controller->pending))
  96                         schedule_delayed_work(&led_dat->controller->work,
  97                                               (HZ/1000) + 1);
  98         }
  99 }
 100
 101 static int __init led_nu801_create(struct led_nu801_data *controller,
 102                                     struct device *parent,
 103                                     int index,
 104                                     enum led_brightness brightness,
 105 #ifdef CONFIG_LEDS_TRIGGERS
 106                                     const char *default_trigger,
 107 #endif
 108                                     const char *color)
 109 {
 110         struct led_nu801_led_data *led = &controller->led_chain[index];
 111         int ret;
 112
 113         scnprintf(led->name, sizeof(led->name), "%s:%s:%s%d",
 114                   controller->device_name, color, controller->name,
 115                   (controller->num_leds - (index + 1)) / NUM_COLORS);
 116         led->cdev.name = led->name;
 117         led->cdev.brightness_set = led_nu801_set;
 118 #ifdef CONFIG_LEDS_TRIGGERS
 119         led->cdev.default_trigger = default_trigger;
 120 #endif
 121         led->level = brightness;
 122         led->controller = controller;
 123         ret = led_classdev_register(parent, &led->cdev);
 124         if (ret < 0)
 125                 goto err;
 126
 127         return 0;
 128
 129 err:
 130         kfree(led);
 131         return ret;
 132 }
 133
 134 static int __init
 135 led_nu801_create_chain(const struct led_nu801_template *template,
 136                         struct led_nu801_data *controller,
 137                         struct device *parent)
 138 {
 139         int ret;
 140         int index;
 141
 142         controller->cki = template->cki;
 143         controller->sdi = template->sdi;
 144         controller->lei = template->lei;
 145         controller->num_leds = template->num_leds * 3;
 146         controller->device_name = template->device_name;
 147         controller->name = template->name;
 148         controller->ndelay = template->ndelay;
 149         atomic_set(&controller->pending, 1);
 150
 151         controller->led_chain = kzalloc(sizeof(struct led_nu801_led_data) *
 152                                         controller->num_leds, GFP_KERNEL);
 153
 154         if (!controller->led_chain)
 155                 return -ENOMEM;
 156
 157         ret = gpio_request(controller->cki, template->name);
 158         if (ret < 0)
 159                 goto err_free_chain;
 160
 161         ret = gpio_request(controller->sdi, template->name);
 162         if (ret < 0)
 163                 goto err_ret_cki;
 164
 165         if (controller->lei >= 0) {
 166                 ret = gpio_request(controller->lei, template->name);
 167                 if (ret < 0)
 168                         goto err_ret_sdi;
 169                 ret = gpio_direction_output(controller->lei, 0);
 170                 if (ret < 0)
 171                         goto err_ret_lei;
 172         }
 173
 174         ret = gpio_direction_output(controller->cki, 0);
 175         if (ret < 0)
 176                 goto err_ret_lei;
 177
 178         ret = gpio_direction_output(controller->sdi, 0);
 179         if (ret < 0)
 180                 goto err_ret_lei;
 181
 182         for (index = 0; index < controller->num_leds; index++) {
 183                 ret = led_nu801_create(controller, parent, index,
 184                         template->init_brightness
 185                         [index % NUM_COLORS],
 186 #ifdef CONFIG_LEDS_TRIGGERS
 187                         template->default_trigger,
 188 #endif
 189                         template->led_colors[index % NUM_COLORS] ?
 190                         template->led_colors[index % NUM_COLORS] :
 191                         led_nu801_colors[index % NUM_COLORS]);
 192                 if (ret < 0)
 193                         goto err_ret_sdi;
 194         }
 195
 196         INIT_DELAYED_WORK(&controller->work, led_nu801_work);
 197         schedule_delayed_work(&controller->work, 0);
 198
 199         return 0;
 200
 201 err_ret_lei:
 202         if (controller->lei >= 0)
 203                 gpio_free(controller->lei);
 204 err_ret_sdi:
 205         gpio_free(controller->sdi);
 206 err_ret_cki:
 207         gpio_free(controller->cki);
 208 err_free_chain:
 209         kfree(controller->led_chain);
 210
 211         return ret;
 212 }
 213
 214 static void led_nu801_delete_chain(struct led_nu801_data *controller)
 215 {
 216         struct led_nu801_led_data *led_chain;
 217         struct led_nu801_led_data *led;
 218         int index;
 219         int num_leds;
 220
 221         led_chain = controller->led_chain;
 222         controller->led_chain = 0;
 223         num_leds = controller->num_leds;
 224         controller->num_leds = 0;
 225         cancel_delayed_work_sync(&controller->work);
 226
 227         for (index = 0; index < num_leds; index++) {
 228                 led = &led_chain[index];
 229                 led_classdev_unregister(&led->cdev);
 230         }
 231
 232         gpio_free(controller->cki);
 233         gpio_free(controller->sdi);
 234         if (controller->lei >= 0)
 235                 gpio_free(controller->lei);
 236
 237         kfree(led_chain);
 238 }
 239
 240 static struct led_nu801_data * __init
 241 leds_nu801_create_of(struct platform_device *pdev)
 242 {
 243         struct device_node *np = pdev->dev.of_node, *child;
 244         struct led_nu801_data *controllers;
 245         int count = 0, ret;
 246         int i = 0;
 247
 248         for_each_child_of_node(np, child)
 249                 count++;
 250         if (!count)
 251                 return NULL;
 252
 253         controllers = kzalloc(sizeof(struct led_nu801_data) * count,
 254                               GFP_KERNEL);
 255         if (!controllers)
 256                 return NULL;
 257
 258         for_each_child_of_node(np, child) {
 259                 const char *state;
 260                 struct led_nu801_template template = {};
 261                 struct device_node *colors;
 262                 int jj;
 263
 264                 template.cki = of_get_named_gpio_flags(child, "cki", 0, NULL);
 265                 template.sdi = of_get_named_gpio_flags(child, "sdi", 0, NULL);
 266                 if (of_find_property(child, "lei", NULL)) {
 267                         template.lei = of_get_named_gpio_flags(child, "lei",
 268                                                                0, NULL);
 269                 } else {
 270                         template.lei = -1;
 271                 }
 272                 of_property_read_u32(child, "ndelay", &template.ndelay);
 273                 of_property_read_u32(child, "num_leds", &template.num_leds);
 274                 template.name = of_get_property(child, "label", NULL) ? :
 275                         child->name;
 276                 template.default_trigger = of_get_property(child,
 277                         "default-trigger", NULL);
 278
 279                 jj = 0;
 280                 for_each_child_of_node(child, colors) {
 281                         template.led_colors[jj] = of_get_property(colors,
 282                                  "label", NULL);
 283                         state = of_get_property(colors, "state", NULL);
 284                         if (!strncmp(state, "off", 3))
 285                                 template.init_brightness[jj] = LED_OFF;
 286                         else if (!strncmp(state, "half", 4))
 287                                 template.init_brightness[jj] = LED_HALF;
 288                         else if (!strncmp(state, "full", 4))
 289                                 template.init_brightness[jj] = LED_FULL;
 290                         jj++;
 291                 }
 292
 293                 ret = led_nu801_create_chain(&template,
 294                                              &controllers[i],
 295                                              &pdev->dev);
 296                 if (ret < 0)
 297                         goto err;
 298                 i++;
 299         }
 300
 301         return controllers;
 302
 303 err:
 304         for (i = i - 1; i >= 0; i--)
 305                 led_nu801_delete_chain(&controllers[i]);
 306         kfree(controllers);
 307         return NULL;
 308 }
 309
 310 static int __init led_nu801_probe(struct platform_device *pdev)
 311 {
 312         struct led_nu801_platform_data *pdata = pdev->dev.platform_data;
 313         struct led_nu801_data *controllers;
 314         int i, ret = 0;
 315
 316         if (!(pdata && pdata->num_controllers)) {
 317                 controllers = leds_nu801_create_of(pdev);
 318                 if (!controllers)
 319                         return -ENODEV;
 320         }
 321
 322         controllers = kzalloc(sizeof(struct led_nu801_data) *
 323                               pdata->num_controllers, GFP_KERNEL);
 324         if (!controllers)
 325                 return -ENOMEM;
 326
 327         for (i = 0; i < pdata->num_controllers; i++) {
 328                 ret = led_nu801_create_chain(&pdata->template[i],
 329                                               &controllers[i],
 330                                               &pdev->dev);
 331                 if (ret < 0)
 332                         goto err;
 333         }
 334
 335         platform_set_drvdata(pdev, controllers);
 336
 337         return 0;
 338
 339 err:
 340         for (i = i - 1; i >= 0; i--)
 341                 led_nu801_delete_chain(&controllers[i]);
 342
 343         kfree(controllers);
 344
 345         return ret;
 346 }
 347
 348 static int led_nu801_remove(struct platform_device *pdev)
 349 {
 350         int i;
 351         struct led_nu801_platform_data *pdata = pdev->dev.platform_data;
 352         struct led_nu801_data *controllers;
 353
 354         controllers = platform_get_drvdata(pdev);
 355
 356         for (i = 0; i < pdata->num_controllers; i++)
 357                 led_nu801_delete_chain(&controllers[i]);
 358
 359         kfree(controllers);
 360
 361         return 0;
 362 }
 363
 364 static const struct of_device_id of_numen_leds_match[] = {
 365         { .compatible = "numen,leds-nu801", },
 366         {},
 367 };
 368 MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
 369
 370 static struct platform_driver led_nu801_driver = {
 371         .probe          = led_nu801_probe,
 372         .remove         = led_nu801_remove,
 373         .driver         = {
 374                 .name   = "leds-nu801",
 375                 .owner  = THIS_MODULE,
 376                 .of_match_table = of_numen_leds_match,
 377         },
 378 };
 379
 380 static int __init led_nu801_init(void)
 381 {
 382         return platform_driver_register(&led_nu801_driver);
 383 }
 384
 385 static void __exit led_nu801_exit(void)
 386 {
 387         platform_driver_unregister(&led_nu801_driver);
 388 }
 389
 390 module_init(led_nu801_init);
 391 module_exit(led_nu801_exit);
 392
 393 MODULE_AUTHOR("Kevin Paul Herbert <kph@meraki.net>");
 394 MODULE_DESCRIPTION("NU801 LED driver");
 395 MODULE_LICENSE("GPL v2");
 396 MODULE_ALIAS("platform:leds-nu801");