drivers/leds/leds-omap-pwm.c

   1 /* drivers/leds/leds-omap_pwm.c
   2  *
   3  * Driver to blink LEDs using OMAP PWM timers
   4  *
   5  * Copyright (C) 2006 Nokia Corporation
   6  * Author: Timo Teras
   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/err.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/leds.h>
  18 #include <linux/ctype.h>
  19 #include <linux/sched.h>
  20 #include <asm/delay.h>
  21 #include <mach/board.h>
  22 #include <mach/dmtimer.h>
  23
  24 struct omap_pwm_led {
  25         struct led_classdev cdev;
  26         struct work_struct work;
  27         struct omap_pwm_led_platform_data *pdata;
  28         struct omap_dm_timer *intensity_timer;
  29         struct omap_dm_timer *blink_timer;
  30         int powered;
  31         unsigned int on_period, off_period;
  32         enum led_brightness brightness;
  33 };
  34
  35 static inline struct omap_pwm_led *pdev_to_omap_pwm_led(struct platform_device *pdev)
  36 {
  37         return platform_get_drvdata(pdev);
  38 }
  39
  40 static inline struct omap_pwm_led *cdev_to_omap_pwm_led(struct led_classdev *led_cdev)
  41 {
  42         return container_of(led_cdev, struct omap_pwm_led, cdev);
  43 }
  44
  45 static inline struct omap_pwm_led *work_to_omap_pwm_led(struct work_struct *work)
  46 {
  47         return container_of(work, struct omap_pwm_led, work);
  48 }
  49
  50 static void omap_pwm_led_set_blink(struct omap_pwm_led *led)
  51 {
  52         if (!led->powered)
  53                 return;
  54
  55         if (led->on_period != 0 && led->off_period != 0) {
  56                 unsigned long load_reg, cmp_reg;
  57
  58                 load_reg = 32768 * (led->on_period + led->off_period) / 1000;
  59                 cmp_reg = 32768 * led->on_period / 1000;
  60
  61                 omap_dm_timer_stop(led->blink_timer);
  62                 omap_dm_timer_set_load(led->blink_timer, 1, -load_reg);
  63                 omap_dm_timer_set_match(led->blink_timer, 1, -cmp_reg);
  64                 omap_dm_timer_set_pwm(led->blink_timer, 1, 1,
  65                                       OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE);
  66                 omap_dm_timer_write_counter(led->blink_timer, -2);
  67                 omap_dm_timer_start(led->blink_timer);
  68         } else {
  69                 omap_dm_timer_set_pwm(led->blink_timer, 1, 1,
  70                                       OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE);
  71                 omap_dm_timer_stop(led->blink_timer);
  72         }
  73 }
  74
  75 static void omap_pwm_led_power_on(struct omap_pwm_led *led)
  76 {
  77         if (led->powered)
  78                 return;
  79         led->powered = 1;
  80
  81         /* Select clock */
  82         omap_dm_timer_enable(led->intensity_timer);
  83         omap_dm_timer_set_source(led->intensity_timer, OMAP_TIMER_SRC_32_KHZ);
  84
  85         /* Turn voltage on */
  86         if (led->pdata->set_power != NULL)
  87                 led->pdata->set_power(led->pdata, 1);
  88
  89         /* Enable PWM timers */
  90         if (led->blink_timer != NULL) {
  91                 omap_dm_timer_enable(led->blink_timer);
  92                 omap_dm_timer_set_source(led->blink_timer,
  93                                          OMAP_TIMER_SRC_32_KHZ);
  94                 omap_pwm_led_set_blink(led);
  95         }
  96
  97         omap_dm_timer_set_load(led->intensity_timer, 1, 0xffffff00);
  98 }
  99
 100 static void omap_pwm_led_power_off(struct omap_pwm_led *led)
 101 {
 102         if (!led->powered)
 103                 return;
 104         led->powered = 0;
 105
 106         /* Everything off */
 107         omap_dm_timer_stop(led->intensity_timer);
 108         omap_dm_timer_disable(led->intensity_timer);
 109
 110         if (led->blink_timer != NULL) {
 111                 omap_dm_timer_stop(led->blink_timer);
 112                 omap_dm_timer_disable(led->blink_timer);
 113         }
 114
 115         if (led->pdata->set_power != NULL)
 116                 led->pdata->set_power(led->pdata, 0);
 117 }
 118
 119 static void omap_pwm_led_set_pwm_cycle(struct omap_pwm_led *led, int cycle)
 120 {
 121         int n;
 122
 123         if (cycle == 0)
 124                 n = 0xff;
 125         else    n = cycle - 1;
 126
 127         if (cycle == LED_FULL) {
 128                 omap_dm_timer_set_pwm(led->intensity_timer, 1, 1,
 129                                       OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE);
 130                 omap_dm_timer_stop(led->intensity_timer);
 131         } else {
 132                 omap_dm_timer_set_pwm(led->intensity_timer, 0, 1,
 133                                       OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE);
 134                 omap_dm_timer_set_match(led->intensity_timer, 1,
 135                                         (0xffffff00) | cycle);
 136                 omap_dm_timer_start(led->intensity_timer);
 137         }
 138 }
 139
 140 static void omap_pwm_led_set(struct led_classdev *led_cdev,
 141                              enum led_brightness value)
 142 {
 143         struct omap_pwm_led *led = cdev_to_omap_pwm_led(led_cdev);
 144
 145         led->brightness = value;
 146         schedule_work(&led->work);
 147 }
 148
 149 static void omap_pwm_led_work(struct work_struct *work)
 150 {
 151         struct omap_pwm_led *led = work_to_omap_pwm_led(work);
 152
 153         if (led->brightness != LED_OFF) {
 154                 omap_pwm_led_power_on(led);
 155                 omap_pwm_led_set_pwm_cycle(led, led->brightness);
 156         } else {
 157                 omap_pwm_led_power_off(led);
 158         }
 159 }
 160
 161 static ssize_t omap_pwm_led_on_period_show(struct device *dev,
 162                                 struct device_attribute *attr, char *buf)
 163 {
 164         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 165         struct omap_pwm_led *led = cdev_to_omap_pwm_led(led_cdev);
 166
 167         return sprintf(buf, "%u\n", led->on_period) + 1;
 168 }
 169
 170 static ssize_t omap_pwm_led_on_period_store(struct device *dev,
 171                                 struct device_attribute *attr,
 172                                 const char *buf, size_t size)
 173 {
 174         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 175         struct omap_pwm_led *led = cdev_to_omap_pwm_led(led_cdev);
 176         int ret = -EINVAL;
 177         unsigned long val;
 178         char *after;
 179         size_t count;
 180
 181         val = simple_strtoul(buf, &after, 10);
 182         count = after - buf;
 183         if (*after && isspace(*after))
 184                 count++;
 185
 186         if (count == size) {
 187                 led->on_period = val;
 188                 omap_pwm_led_set_blink(led);
 189                 ret = count;
 190         }
 191
 192         return ret;
 193 }
 194
 195 static ssize_t omap_pwm_led_off_period_show(struct device *dev,
 196                                 struct device_attribute *attr, char *buf)
 197 {
 198         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 199         struct omap_pwm_led *led = cdev_to_omap_pwm_led(led_cdev);
 200
 201         return sprintf(buf, "%u\n", led->off_period) + 1;
 202 }
 203
 204 static ssize_t omap_pwm_led_off_period_store(struct device *dev,
 205                                         struct device_attribute *attr,
 206                                         const char *buf, size_t size)
 207 {
 208         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 209         struct omap_pwm_led *led = cdev_to_omap_pwm_led(led_cdev);
 210         int ret = -EINVAL;
 211         unsigned long val;
 212         char *after;
 213         size_t count;
 214
 215         val = simple_strtoul(buf, &after, 10);
 216         count = after - buf;
 217         if (*after && isspace(*after))
 218                 count++;
 219
 220         if (count == size) {
 221                 led->off_period = val;
 222                 omap_pwm_led_set_blink(led);
 223                 ret = count;
 224         }
 225
 226         return ret;
 227 }
 228
 229 static DEVICE_ATTR(on_period, 0644, omap_pwm_led_on_period_show,
 230                                 omap_pwm_led_on_period_store);
 231 static DEVICE_ATTR(off_period, 0644, omap_pwm_led_off_period_show,
 232                                 omap_pwm_led_off_period_store);
 233
 234 static int omap_pwm_led_probe(struct platform_device *pdev)
 235 {
 236         struct omap_pwm_led_platform_data *pdata = pdev->dev.platform_data;
 237         struct omap_pwm_led *led;
 238         int ret;
 239
 240         led = kzalloc(sizeof(struct omap_pwm_led), GFP_KERNEL);
 241         if (led == NULL) {
 242                 dev_err(&pdev->dev, "No memory for device\n");
 243                 return -ENOMEM;
 244         }
 245
 246         platform_set_drvdata(pdev, led);
 247         led->cdev.brightness_set = omap_pwm_led_set;
 248         led->cdev.default_trigger = NULL;
 249         led->cdev.name = pdata->name;
 250         led->pdata = pdata;
 251         led->brightness = LED_OFF;
 252         INIT_WORK(&led->work, omap_pwm_led_work);
 253
 254         dev_info(&pdev->dev, "OMAP PWM LED (%s) at GP timer %d/%d\n",
 255                  pdata->name, pdata->intensity_timer, pdata->blink_timer);
 256
 257         /* register our new led device */
 258         ret = led_classdev_register(&pdev->dev, &led->cdev);
 259         if (ret < 0) {
 260                 dev_err(&pdev->dev, "led_classdev_register failed\n");
 261                 goto error_classdev;
 262         }
 263
 264         /* get related dm timers */
 265         led->intensity_timer = omap_dm_timer_request_specific(pdata->intensity_timer);
 266         if (led->intensity_timer == NULL) {
 267                 dev_err(&pdev->dev, "failed to request intensity pwm timer\n");
 268                 ret = -ENODEV;
 269                 goto error_intensity;
 270         }
 271         omap_dm_timer_disable(led->intensity_timer);
 272
 273         if (pdata->blink_timer != 0) {
 274                 led->blink_timer = omap_dm_timer_request_specific(pdata->blink_timer);
 275                 if (led->blink_timer == NULL) {
 276                         dev_err(&pdev->dev, "failed to request blinking pwm timer\n");
 277                         ret = -ENODEV;
 278                         goto error_blink1;
 279                 }
 280                 omap_dm_timer_disable(led->blink_timer);
 281
 282                 ret = device_create_file(led->cdev.dev,
 283                                                &dev_attr_on_period);
 284                 if(ret)
 285                         goto error_blink2;
 286
 287                 ret = device_create_file(led->cdev.dev,
 288                                         &dev_attr_off_period);
 289                 if(ret)
 290                         goto error_blink3;
 291
 292         }
 293
 294         return 0;
 295
 296 error_blink3:
 297         device_remove_file(led->cdev.dev,
 298                                  &dev_attr_on_period);
 299 error_blink2:
 300         dev_err(&pdev->dev, "failed to create device file(s)\n");
 301 error_blink1:
 302         omap_dm_timer_free(led->intensity_timer);
 303 error_intensity:
 304         led_classdev_unregister(&led->cdev);
 305 error_classdev:
 306         kfree(led);
 307         return ret;
 308 }
 309
 310 static int omap_pwm_led_remove(struct platform_device *pdev)
 311 {
 312         struct omap_pwm_led *led = pdev_to_omap_pwm_led(pdev);
 313
 314         device_remove_file(led->cdev.dev,
 315                                  &dev_attr_on_period);
 316         device_remove_file(led->cdev.dev,
 317                                  &dev_attr_off_period);
 318         led_classdev_unregister(&led->cdev);
 319
 320         omap_pwm_led_set(&led->cdev, LED_OFF);
 321         if (led->blink_timer != NULL)
 322                 omap_dm_timer_free(led->blink_timer);
 323         omap_dm_timer_free(led->intensity_timer);
 324         kfree(led);
 325
 326         return 0;
 327 }
 328
 329 #ifdef CONFIG_PM
 330 static int omap_pwm_led_suspend(struct platform_device *pdev, pm_message_t state)
 331 {
 332         struct omap_pwm_led *led = pdev_to_omap_pwm_led(pdev);
 333
 334         led_classdev_suspend(&led->cdev);
 335         return 0;
 336 }
 337
 338 static int omap_pwm_led_resume(struct platform_device *pdev)
 339 {
 340         struct omap_pwm_led *led = pdev_to_omap_pwm_led(pdev);
 341
 342         led_classdev_resume(&led->cdev);
 343         return 0;
 344 }
 345 #else
 346 #define omap_pwm_led_suspend NULL
 347 #define omap_pwm_led_resume NULL
 348 #endif
 349
 350 static struct platform_driver omap_pwm_led_driver = {
 351         .probe          = omap_pwm_led_probe,
 352         .remove         = omap_pwm_led_remove,
 353         .suspend        = omap_pwm_led_suspend,
 354         .resume         = omap_pwm_led_resume,
 355         .driver         = {
 356                 .name           = "omap_pwm_led",
 357                 .owner          = THIS_MODULE,
 358         },
 359 };
 360
 361 static int __init omap_pwm_led_init(void)
 362 {
 363         return platform_driver_register(&omap_pwm_led_driver);
 364 }
 365
 366 static void __exit omap_pwm_led_exit(void)
 367 {
 368         platform_driver_unregister(&omap_pwm_led_driver);
 369 }
 370
 371 module_init(omap_pwm_led_init);
 372 module_exit(omap_pwm_led_exit);
 373
 374 MODULE_AUTHOR("Timo Teras");
 375 MODULE_DESCRIPTION("OMAP PWM LED driver");
 376 MODULE_LICENSE("GPL");