leds-lp3944.c 10 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442
  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * leds-lp3944.c - driver for National Semiconductor LP3944 Funlight Chip
  4. *
  5. * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>
  6. */
  7. /*
  8. * I2C driver for National Semiconductor LP3944 Funlight Chip
  9. * http://www.national.com/pf/LP/LP3944.html
  10. *
  11. * This helper chip can drive up to 8 leds, with two programmable DIM modes;
  12. * it could even be used as a gpio expander but this driver assumes it is used
  13. * as a led controller.
  14. *
  15. * The DIM modes are used to set _blink_ patterns for leds, the pattern is
  16. * specified supplying two parameters:
  17. * - period: from 0s to 1.6s
  18. * - duty cycle: percentage of the period the led is on, from 0 to 100
  19. *
  20. * LP3944 can be found on Motorola A910 smartphone, where it drives the rgb
  21. * leds, the camera flash light and the displays backlights.
  22. */
  23. #include <linux/module.h>
  24. #include <linux/i2c.h>
  25. #include <linux/slab.h>
  26. #include <linux/leds.h>
  27. #include <linux/mutex.h>
  28. #include <linux/leds-lp3944.h>
  29. /* Read Only Registers */
  30. #define LP3944_REG_INPUT1 0x00 /* LEDs 0-7 InputRegister (Read Only) */
  31. #define LP3944_REG_REGISTER1 0x01 /* None (Read Only) */
  32. #define LP3944_REG_PSC0 0x02 /* Frequency Prescaler 0 (R/W) */
  33. #define LP3944_REG_PWM0 0x03 /* PWM Register 0 (R/W) */
  34. #define LP3944_REG_PSC1 0x04 /* Frequency Prescaler 1 (R/W) */
  35. #define LP3944_REG_PWM1 0x05 /* PWM Register 1 (R/W) */
  36. #define LP3944_REG_LS0 0x06 /* LEDs 0-3 Selector (R/W) */
  37. #define LP3944_REG_LS1 0x07 /* LEDs 4-7 Selector (R/W) */
  38. /* These registers are not used to control leds in LP3944, they can store
  39. * arbitrary values which the chip will ignore.
  40. */
  41. #define LP3944_REG_REGISTER8 0x08
  42. #define LP3944_REG_REGISTER9 0x09
  43. #define LP3944_DIM0 0
  44. #define LP3944_DIM1 1
  45. /* period in ms */
  46. #define LP3944_PERIOD_MIN 0
  47. #define LP3944_PERIOD_MAX 1600
  48. /* duty cycle is a percentage */
  49. #define LP3944_DUTY_CYCLE_MIN 0
  50. #define LP3944_DUTY_CYCLE_MAX 100
  51. #define ldev_to_led(c) container_of(c, struct lp3944_led_data, ldev)
  52. /* Saved data */
  53. struct lp3944_led_data {
  54. u8 id;
  55. enum lp3944_type type;
  56. struct led_classdev ldev;
  57. struct i2c_client *client;
  58. };
  59. struct lp3944_data {
  60. struct mutex lock;
  61. struct i2c_client *client;
  62. struct lp3944_led_data leds[LP3944_LEDS_MAX];
  63. };
  64. static int lp3944_reg_read(struct i2c_client *client, u8 reg, u8 *value)
  65. {
  66. int tmp;
  67. tmp = i2c_smbus_read_byte_data(client, reg);
  68. if (tmp < 0)
  69. return tmp;
  70. *value = tmp;
  71. return 0;
  72. }
  73. static int lp3944_reg_write(struct i2c_client *client, u8 reg, u8 value)
  74. {
  75. return i2c_smbus_write_byte_data(client, reg, value);
  76. }
  77. /**
  78. * Set the period for DIM status
  79. *
  80. * @client: the i2c client
  81. * @dim: either LP3944_DIM0 or LP3944_DIM1
  82. * @period: period of a blink, that is a on/off cycle, expressed in ms.
  83. */
  84. static int lp3944_dim_set_period(struct i2c_client *client, u8 dim, u16 period)
  85. {
  86. u8 psc_reg;
  87. u8 psc_value;
  88. int err;
  89. if (dim == LP3944_DIM0)
  90. psc_reg = LP3944_REG_PSC0;
  91. else if (dim == LP3944_DIM1)
  92. psc_reg = LP3944_REG_PSC1;
  93. else
  94. return -EINVAL;
  95. /* Convert period to Prescaler value */
  96. if (period > LP3944_PERIOD_MAX)
  97. return -EINVAL;
  98. psc_value = (period * 255) / LP3944_PERIOD_MAX;
  99. err = lp3944_reg_write(client, psc_reg, psc_value);
  100. return err;
  101. }
  102. /**
  103. * Set the duty cycle for DIM status
  104. *
  105. * @client: the i2c client
  106. * @dim: either LP3944_DIM0 or LP3944_DIM1
  107. * @duty_cycle: percentage of a period during which a led is ON
  108. */
  109. static int lp3944_dim_set_dutycycle(struct i2c_client *client, u8 dim,
  110. u8 duty_cycle)
  111. {
  112. u8 pwm_reg;
  113. u8 pwm_value;
  114. int err;
  115. if (dim == LP3944_DIM0)
  116. pwm_reg = LP3944_REG_PWM0;
  117. else if (dim == LP3944_DIM1)
  118. pwm_reg = LP3944_REG_PWM1;
  119. else
  120. return -EINVAL;
  121. /* Convert duty cycle to PWM value */
  122. if (duty_cycle > LP3944_DUTY_CYCLE_MAX)
  123. return -EINVAL;
  124. pwm_value = (duty_cycle * 255) / LP3944_DUTY_CYCLE_MAX;
  125. err = lp3944_reg_write(client, pwm_reg, pwm_value);
  126. return err;
  127. }
  128. /**
  129. * Set the led status
  130. *
  131. * @led: a lp3944_led_data structure
  132. * @status: one of LP3944_LED_STATUS_OFF
  133. * LP3944_LED_STATUS_ON
  134. * LP3944_LED_STATUS_DIM0
  135. * LP3944_LED_STATUS_DIM1
  136. */
  137. static int lp3944_led_set(struct lp3944_led_data *led, u8 status)
  138. {
  139. struct lp3944_data *data = i2c_get_clientdata(led->client);
  140. u8 id = led->id;
  141. u8 reg;
  142. u8 val = 0;
  143. int err;
  144. dev_dbg(&led->client->dev, "%s: %s, status before normalization:%d\n",
  145. __func__, led->ldev.name, status);
  146. switch (id) {
  147. case LP3944_LED0:
  148. case LP3944_LED1:
  149. case LP3944_LED2:
  150. case LP3944_LED3:
  151. reg = LP3944_REG_LS0;
  152. break;
  153. case LP3944_LED4:
  154. case LP3944_LED5:
  155. case LP3944_LED6:
  156. case LP3944_LED7:
  157. id -= LP3944_LED4;
  158. reg = LP3944_REG_LS1;
  159. break;
  160. default:
  161. return -EINVAL;
  162. }
  163. if (status > LP3944_LED_STATUS_DIM1)
  164. return -EINVAL;
  165. /*
  166. * Invert status only when it's < 2 (i.e. 0 or 1) which means it's
  167. * controlling the on/off state directly.
  168. * When, instead, status is >= 2 don't invert it because it would mean
  169. * to mess with the hardware blinking mode.
  170. */
  171. if (led->type == LP3944_LED_TYPE_LED_INVERTED && status < 2)
  172. status = 1 - status;
  173. mutex_lock(&data->lock);
  174. lp3944_reg_read(led->client, reg, &val);
  175. val &= ~(LP3944_LED_STATUS_MASK << (id << 1));
  176. val |= (status << (id << 1));
  177. dev_dbg(&led->client->dev, "%s: %s, reg:%d id:%d status:%d val:%#x\n",
  178. __func__, led->ldev.name, reg, id, status, val);
  179. /* set led status */
  180. err = lp3944_reg_write(led->client, reg, val);
  181. mutex_unlock(&data->lock);
  182. return err;
  183. }
  184. static int lp3944_led_set_blink(struct led_classdev *led_cdev,
  185. unsigned long *delay_on,
  186. unsigned long *delay_off)
  187. {
  188. struct lp3944_led_data *led = ldev_to_led(led_cdev);
  189. u16 period;
  190. u8 duty_cycle;
  191. int err;
  192. /* units are in ms */
  193. if (*delay_on + *delay_off > LP3944_PERIOD_MAX)
  194. return -EINVAL;
  195. if (*delay_on == 0 && *delay_off == 0) {
  196. /* Special case: the leds subsystem requires a default user
  197. * friendly blink pattern for the LED. Let's blink the led
  198. * slowly (1Hz).
  199. */
  200. *delay_on = 500;
  201. *delay_off = 500;
  202. }
  203. period = (*delay_on) + (*delay_off);
  204. /* duty_cycle is the percentage of period during which the led is ON */
  205. duty_cycle = 100 * (*delay_on) / period;
  206. /* invert duty cycle for inverted leds, this has the same effect of
  207. * swapping delay_on and delay_off
  208. */
  209. if (led->type == LP3944_LED_TYPE_LED_INVERTED)
  210. duty_cycle = 100 - duty_cycle;
  211. /* NOTE: using always the first DIM mode, this means that all leds
  212. * will have the same blinking pattern.
  213. *
  214. * We could find a way later to have two leds blinking in hardware
  215. * with different patterns at the same time, falling back to software
  216. * control for the other ones.
  217. */
  218. err = lp3944_dim_set_period(led->client, LP3944_DIM0, period);
  219. if (err)
  220. return err;
  221. err = lp3944_dim_set_dutycycle(led->client, LP3944_DIM0, duty_cycle);
  222. if (err)
  223. return err;
  224. dev_dbg(&led->client->dev, "%s: OK hardware accelerated blink!\n",
  225. __func__);
  226. lp3944_led_set(led, LP3944_LED_STATUS_DIM0);
  227. return 0;
  228. }
  229. static int lp3944_led_set_brightness(struct led_classdev *led_cdev,
  230. enum led_brightness brightness)
  231. {
  232. struct lp3944_led_data *led = ldev_to_led(led_cdev);
  233. dev_dbg(&led->client->dev, "%s: %s, %d\n",
  234. __func__, led_cdev->name, brightness);
  235. return lp3944_led_set(led, !!brightness);
  236. }
  237. static int lp3944_configure(struct i2c_client *client,
  238. struct lp3944_data *data,
  239. struct lp3944_platform_data *pdata)
  240. {
  241. int i, err = 0;
  242. for (i = 0; i < pdata->leds_size; i++) {
  243. struct lp3944_led *pled = &pdata->leds[i];
  244. struct lp3944_led_data *led = &data->leds[i];
  245. led->client = client;
  246. led->id = i;
  247. switch (pled->type) {
  248. case LP3944_LED_TYPE_LED:
  249. case LP3944_LED_TYPE_LED_INVERTED:
  250. led->type = pled->type;
  251. led->ldev.name = pled->name;
  252. led->ldev.max_brightness = 1;
  253. led->ldev.brightness_set_blocking =
  254. lp3944_led_set_brightness;
  255. led->ldev.blink_set = lp3944_led_set_blink;
  256. led->ldev.flags = LED_CORE_SUSPENDRESUME;
  257. err = led_classdev_register(&client->dev, &led->ldev);
  258. if (err < 0) {
  259. dev_err(&client->dev,
  260. "couldn't register LED %s\n",
  261. led->ldev.name);
  262. goto exit;
  263. }
  264. /* to expose the default value to userspace */
  265. led->ldev.brightness =
  266. (enum led_brightness) pled->status;
  267. /* Set the default led status */
  268. err = lp3944_led_set(led, pled->status);
  269. if (err < 0) {
  270. dev_err(&client->dev,
  271. "%s couldn't set STATUS %d\n",
  272. led->ldev.name, pled->status);
  273. goto exit;
  274. }
  275. break;
  276. case LP3944_LED_TYPE_NONE:
  277. default:
  278. break;
  279. }
  280. }
  281. return 0;
  282. exit:
  283. if (i > 0)
  284. for (i = i - 1; i >= 0; i--)
  285. switch (pdata->leds[i].type) {
  286. case LP3944_LED_TYPE_LED:
  287. case LP3944_LED_TYPE_LED_INVERTED:
  288. led_classdev_unregister(&data->leds[i].ldev);
  289. break;
  290. case LP3944_LED_TYPE_NONE:
  291. default:
  292. break;
  293. }
  294. return err;
  295. }
  296. static int lp3944_probe(struct i2c_client *client,
  297. const struct i2c_device_id *id)
  298. {
  299. struct lp3944_platform_data *lp3944_pdata =
  300. dev_get_platdata(&client->dev);
  301. struct lp3944_data *data;
  302. int err;
  303. if (lp3944_pdata == NULL) {
  304. dev_err(&client->dev, "no platform data\n");
  305. return -EINVAL;
  306. }
  307. /* Let's see whether this adapter can support what we need. */
  308. if (!i2c_check_functionality(client->adapter,
  309. I2C_FUNC_SMBUS_BYTE_DATA)) {
  310. dev_err(&client->dev, "insufficient functionality!\n");
  311. return -ENODEV;
  312. }
  313. data = devm_kzalloc(&client->dev, sizeof(struct lp3944_data),
  314. GFP_KERNEL);
  315. if (!data)
  316. return -ENOMEM;
  317. data->client = client;
  318. i2c_set_clientdata(client, data);
  319. mutex_init(&data->lock);
  320. err = lp3944_configure(client, data, lp3944_pdata);
  321. if (err < 0)
  322. return err;
  323. dev_info(&client->dev, "lp3944 enabled\n");
  324. return 0;
  325. }
  326. static int lp3944_remove(struct i2c_client *client)
  327. {
  328. struct lp3944_platform_data *pdata = dev_get_platdata(&client->dev);
  329. struct lp3944_data *data = i2c_get_clientdata(client);
  330. int i;
  331. for (i = 0; i < pdata->leds_size; i++)
  332. switch (data->leds[i].type) {
  333. case LP3944_LED_TYPE_LED:
  334. case LP3944_LED_TYPE_LED_INVERTED:
  335. led_classdev_unregister(&data->leds[i].ldev);
  336. break;
  337. case LP3944_LED_TYPE_NONE:
  338. default:
  339. break;
  340. }
  341. return 0;
  342. }
  343. /* lp3944 i2c driver struct */
  344. static const struct i2c_device_id lp3944_id[] = {
  345. {"lp3944", 0},
  346. {}
  347. };
  348. MODULE_DEVICE_TABLE(i2c, lp3944_id);
  349. static struct i2c_driver lp3944_driver = {
  350. .driver = {
  351. .name = "lp3944",
  352. },
  353. .probe = lp3944_probe,
  354. .remove = lp3944_remove,
  355. .id_table = lp3944_id,
  356. };
  357. module_i2c_driver(lp3944_driver);
  358. MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
  359. MODULE_DESCRIPTION("LP3944 Fun Light Chip");
  360. MODULE_LICENSE("GPL");