1 /*
2 * TI LP855x Backlight Driver
3 *
4 * Copyright (C) 2011 Texas Instruments
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/i2c.h>
15 #include <linux/backlight.h>
16 #include <linux/delay.h>
17 #include <linux/err.h>
18 #include <linux/of.h>
19 #include <linux/platform_data/lp855x.h>
20 #include <linux/pwm.h>
21 #include <linux/regulator/consumer.h>
22
23 /* LP8550/1/2/3/6 Registers */
24 #define LP855X_BRIGHTNESS_CTRL 0x00
25 #define LP855X_DEVICE_CTRL 0x01
26 #define LP855X_EEPROM_START 0xA0
27 #define LP855X_EEPROM_END 0xA7
28 #define LP8556_EPROM_START 0xA0
29 #define LP8556_EPROM_END 0xAF
30
31 /* LP8555/7 Registers */
32 #define LP8557_BL_CMD 0x00
33 #define LP8557_BL_MASK 0x01
34 #define LP8557_BL_ON 0x01
35 #define LP8557_BL_OFF 0x00
36 #define LP8557_BRIGHTNESS_CTRL 0x04
37 #define LP8557_CONFIG 0x10
38 #define LP8555_EPROM_START 0x10
39 #define LP8555_EPROM_END 0x7A
40 #define LP8557_EPROM_START 0x10
41 #define LP8557_EPROM_END 0x1E
42
43 #define DEFAULT_BL_NAME "lcd-backlight"
44 #define MAX_BRIGHTNESS 255
45
46 enum lp855x_brightness_ctrl_mode {
47 PWM_BASED = 1,
48 REGISTER_BASED,
49 };
50
51 struct lp855x;
52
53 /*
54 * struct lp855x_device_config
55 * @pre_init_device: init device function call before updating the brightness
56 * @reg_brightness: register address for brigthenss control
57 * @reg_devicectrl: register address for device control
58 * @post_init_device: late init device function call
59 */
60 struct lp855x_device_config {
61 int (*pre_init_device)(struct lp855x *);
62 u8 reg_brightness;
63 u8 reg_devicectrl;
64 int (*post_init_device)(struct lp855x *);
65 };
66
67 struct lp855x {
68 const char *chipname;
69 enum lp855x_chip_id chip_id;
70 enum lp855x_brightness_ctrl_mode mode;
71 struct lp855x_device_config *cfg;
72 struct i2c_client *client;
73 struct backlight_device *bl;
74 struct device *dev;
75 struct lp855x_platform_data *pdata;
76 struct pwm_device *pwm;
77 struct regulator *supply; /* regulator for VDD input */
78 struct regulator *enable; /* regulator for EN/VDDIO input */
79 };
80
lp855x_write_byte(struct lp855x * lp,u8 reg,u8 data)81 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
82 {
83 return i2c_smbus_write_byte_data(lp->client, reg, data);
84 }
85
lp855x_update_bit(struct lp855x * lp,u8 reg,u8 mask,u8 data)86 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
87 {
88 int ret;
89 u8 tmp;
90
91 ret = i2c_smbus_read_byte_data(lp->client, reg);
92 if (ret < 0) {
93 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
94 return ret;
95 }
96
97 tmp = (u8)ret;
98 tmp &= ~mask;
99 tmp |= data & mask;
100
101 return lp855x_write_byte(lp, reg, tmp);
102 }
103
lp855x_is_valid_rom_area(struct lp855x * lp,u8 addr)104 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
105 {
106 u8 start, end;
107
108 switch (lp->chip_id) {
109 case LP8550:
110 case LP8551:
111 case LP8552:
112 case LP8553:
113 start = LP855X_EEPROM_START;
114 end = LP855X_EEPROM_END;
115 break;
116 case LP8556:
117 start = LP8556_EPROM_START;
118 end = LP8556_EPROM_END;
119 break;
120 case LP8555:
121 start = LP8555_EPROM_START;
122 end = LP8555_EPROM_END;
123 break;
124 case LP8557:
125 start = LP8557_EPROM_START;
126 end = LP8557_EPROM_END;
127 break;
128 default:
129 return false;
130 }
131
132 return addr >= start && addr <= end;
133 }
134
lp8557_bl_off(struct lp855x * lp)135 static int lp8557_bl_off(struct lp855x *lp)
136 {
137 /* BL_ON = 0 before updating EPROM settings */
138 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
139 LP8557_BL_OFF);
140 }
141
lp8557_bl_on(struct lp855x * lp)142 static int lp8557_bl_on(struct lp855x *lp)
143 {
144 /* BL_ON = 1 after updating EPROM settings */
145 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
146 LP8557_BL_ON);
147 }
148
149 static struct lp855x_device_config lp855x_dev_cfg = {
150 .reg_brightness = LP855X_BRIGHTNESS_CTRL,
151 .reg_devicectrl = LP855X_DEVICE_CTRL,
152 };
153
154 static struct lp855x_device_config lp8557_dev_cfg = {
155 .reg_brightness = LP8557_BRIGHTNESS_CTRL,
156 .reg_devicectrl = LP8557_CONFIG,
157 .pre_init_device = lp8557_bl_off,
158 .post_init_device = lp8557_bl_on,
159 };
160
161 /*
162 * Device specific configuration flow
163 *
164 * a) pre_init_device(optional)
165 * b) update the brightness register
166 * c) update device control register
167 * d) update ROM area(optional)
168 * e) post_init_device(optional)
169 *
170 */
lp855x_configure(struct lp855x * lp)171 static int lp855x_configure(struct lp855x *lp)
172 {
173 u8 val, addr;
174 int i, ret;
175 struct lp855x_platform_data *pd = lp->pdata;
176
177 switch (lp->chip_id) {
178 case LP8550:
179 case LP8551:
180 case LP8552:
181 case LP8553:
182 case LP8556:
183 lp->cfg = &lp855x_dev_cfg;
184 break;
185 case LP8555:
186 case LP8557:
187 lp->cfg = &lp8557_dev_cfg;
188 break;
189 default:
190 return -EINVAL;
191 }
192
193 if (lp->cfg->pre_init_device) {
194 ret = lp->cfg->pre_init_device(lp);
195 if (ret) {
196 dev_err(lp->dev, "pre init device err: %d\n", ret);
197 goto err;
198 }
199 }
200
201 val = pd->initial_brightness;
202 ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
203 if (ret)
204 goto err;
205
206 val = pd->device_control;
207 ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
208 if (ret)
209 goto err;
210
211 if (pd->size_program > 0) {
212 for (i = 0; i < pd->size_program; i++) {
213 addr = pd->rom_data[i].addr;
214 val = pd->rom_data[i].val;
215 if (!lp855x_is_valid_rom_area(lp, addr))
216 continue;
217
218 ret = lp855x_write_byte(lp, addr, val);
219 if (ret)
220 goto err;
221 }
222 }
223
224 if (lp->cfg->post_init_device) {
225 ret = lp->cfg->post_init_device(lp);
226 if (ret) {
227 dev_err(lp->dev, "post init device err: %d\n", ret);
228 goto err;
229 }
230 }
231
232 return 0;
233
234 err:
235 return ret;
236 }
237
lp855x_pwm_ctrl(struct lp855x * lp,int br,int max_br)238 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
239 {
240 unsigned int period = lp->pdata->period_ns;
241 unsigned int duty = br * period / max_br;
242 struct pwm_device *pwm;
243
244 /* request pwm device with the consumer name */
245 if (!lp->pwm) {
246 pwm = devm_pwm_get(lp->dev, lp->chipname);
247 if (IS_ERR(pwm))
248 return;
249
250 lp->pwm = pwm;
251
252 /*
253 * FIXME: pwm_apply_args() should be removed when switching to
254 * the atomic PWM API.
255 */
256 pwm_apply_args(pwm);
257 }
258
259 pwm_config(lp->pwm, duty, period);
260 if (duty)
261 pwm_enable(lp->pwm);
262 else
263 pwm_disable(lp->pwm);
264 }
265
lp855x_bl_update_status(struct backlight_device * bl)266 static int lp855x_bl_update_status(struct backlight_device *bl)
267 {
268 struct lp855x *lp = bl_get_data(bl);
269 int brightness = bl->props.brightness;
270
271 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
272 brightness = 0;
273
274 if (lp->mode == PWM_BASED)
275 lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
276 else if (lp->mode == REGISTER_BASED)
277 lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);
278
279 return 0;
280 }
281
282 static const struct backlight_ops lp855x_bl_ops = {
283 .options = BL_CORE_SUSPENDRESUME,
284 .update_status = lp855x_bl_update_status,
285 };
286
lp855x_backlight_register(struct lp855x * lp)287 static int lp855x_backlight_register(struct lp855x *lp)
288 {
289 struct backlight_device *bl;
290 struct backlight_properties props;
291 struct lp855x_platform_data *pdata = lp->pdata;
292 const char *name = pdata->name ? : DEFAULT_BL_NAME;
293
294 memset(&props, 0, sizeof(props));
295 props.type = BACKLIGHT_PLATFORM;
296 props.max_brightness = MAX_BRIGHTNESS;
297
298 if (pdata->initial_brightness > props.max_brightness)
299 pdata->initial_brightness = props.max_brightness;
300
301 props.brightness = pdata->initial_brightness;
302
303 bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
304 &lp855x_bl_ops, &props);
305 if (IS_ERR(bl))
306 return PTR_ERR(bl);
307
308 lp->bl = bl;
309
310 return 0;
311 }
312
lp855x_get_chip_id(struct device * dev,struct device_attribute * attr,char * buf)313 static ssize_t lp855x_get_chip_id(struct device *dev,
314 struct device_attribute *attr, char *buf)
315 {
316 struct lp855x *lp = dev_get_drvdata(dev);
317
318 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
319 }
320
lp855x_get_bl_ctl_mode(struct device * dev,struct device_attribute * attr,char * buf)321 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
322 struct device_attribute *attr, char *buf)
323 {
324 struct lp855x *lp = dev_get_drvdata(dev);
325 char *strmode = NULL;
326
327 if (lp->mode == PWM_BASED)
328 strmode = "pwm based";
329 else if (lp->mode == REGISTER_BASED)
330 strmode = "register based";
331
332 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
333 }
334
335 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
336 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
337
338 static struct attribute *lp855x_attributes[] = {
339 &dev_attr_chip_id.attr,
340 &dev_attr_bl_ctl_mode.attr,
341 NULL,
342 };
343
344 static const struct attribute_group lp855x_attr_group = {
345 .attrs = lp855x_attributes,
346 };
347
348 #ifdef CONFIG_OF
lp855x_parse_dt(struct lp855x * lp)349 static int lp855x_parse_dt(struct lp855x *lp)
350 {
351 struct device *dev = lp->dev;
352 struct device_node *node = dev->of_node;
353 struct lp855x_platform_data *pdata;
354 int rom_length;
355
356 if (!node) {
357 dev_err(dev, "no platform data\n");
358 return -EINVAL;
359 }
360
361 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
362 if (!pdata)
363 return -ENOMEM;
364
365 of_property_read_string(node, "bl-name", &pdata->name);
366 of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
367 of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
368 of_property_read_u32(node, "pwm-period", &pdata->period_ns);
369
370 /* Fill ROM platform data if defined */
371 rom_length = of_get_child_count(node);
372 if (rom_length > 0) {
373 struct lp855x_rom_data *rom;
374 struct device_node *child;
375 int i = 0;
376
377 rom = devm_kcalloc(dev, rom_length, sizeof(*rom), GFP_KERNEL);
378 if (!rom)
379 return -ENOMEM;
380
381 for_each_child_of_node(node, child) {
382 of_property_read_u8(child, "rom-addr", &rom[i].addr);
383 of_property_read_u8(child, "rom-val", &rom[i].val);
384 i++;
385 }
386
387 pdata->size_program = rom_length;
388 pdata->rom_data = &rom[0];
389 }
390
391 lp->pdata = pdata;
392
393 return 0;
394 }
395 #else
lp855x_parse_dt(struct lp855x * lp)396 static int lp855x_parse_dt(struct lp855x *lp)
397 {
398 return -EINVAL;
399 }
400 #endif
401
lp855x_probe(struct i2c_client * cl,const struct i2c_device_id * id)402 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
403 {
404 struct lp855x *lp;
405 int ret;
406
407 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
408 return -EIO;
409
410 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
411 if (!lp)
412 return -ENOMEM;
413
414 lp->client = cl;
415 lp->dev = &cl->dev;
416 lp->chipname = id->name;
417 lp->chip_id = id->driver_data;
418 lp->pdata = dev_get_platdata(&cl->dev);
419
420 if (!lp->pdata) {
421 ret = lp855x_parse_dt(lp);
422 if (ret < 0)
423 return ret;
424 }
425
426 if (lp->pdata->period_ns > 0)
427 lp->mode = PWM_BASED;
428 else
429 lp->mode = REGISTER_BASED;
430
431 lp->supply = devm_regulator_get(lp->dev, "power");
432 if (IS_ERR(lp->supply)) {
433 if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
434 return -EPROBE_DEFER;
435 lp->supply = NULL;
436 }
437
438 lp->enable = devm_regulator_get_optional(lp->dev, "enable");
439 if (IS_ERR(lp->enable)) {
440 ret = PTR_ERR(lp->enable);
441 if (ret == -ENODEV) {
442 lp->enable = NULL;
443 } else {
444 if (ret != -EPROBE_DEFER)
445 dev_err(lp->dev, "error getting enable regulator: %d\n",
446 ret);
447 return ret;
448 }
449 }
450
451 if (lp->supply) {
452 ret = regulator_enable(lp->supply);
453 if (ret < 0) {
454 dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
455 return ret;
456 }
457 }
458
459 if (lp->enable) {
460 ret = regulator_enable(lp->enable);
461 if (ret < 0) {
462 dev_err(lp->dev, "failed to enable vddio: %d\n", ret);
463 return ret;
464 }
465
466 /*
467 * LP8555 datasheet says t_RESPONSE (time between VDDIO and
468 * I2C) is 1ms.
469 */
470 usleep_range(1000, 2000);
471 }
472
473 i2c_set_clientdata(cl, lp);
474
475 ret = lp855x_configure(lp);
476 if (ret) {
477 dev_err(lp->dev, "device config err: %d", ret);
478 return ret;
479 }
480
481 ret = lp855x_backlight_register(lp);
482 if (ret) {
483 dev_err(lp->dev,
484 "failed to register backlight. err: %d\n", ret);
485 return ret;
486 }
487
488 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
489 if (ret) {
490 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
491 return ret;
492 }
493
494 backlight_update_status(lp->bl);
495 return 0;
496 }
497
lp855x_remove(struct i2c_client * cl)498 static int lp855x_remove(struct i2c_client *cl)
499 {
500 struct lp855x *lp = i2c_get_clientdata(cl);
501
502 lp->bl->props.brightness = 0;
503 backlight_update_status(lp->bl);
504 if (lp->supply)
505 regulator_disable(lp->supply);
506 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
507
508 return 0;
509 }
510
511 static const struct of_device_id lp855x_dt_ids[] = {
512 { .compatible = "ti,lp8550", },
513 { .compatible = "ti,lp8551", },
514 { .compatible = "ti,lp8552", },
515 { .compatible = "ti,lp8553", },
516 { .compatible = "ti,lp8555", },
517 { .compatible = "ti,lp8556", },
518 { .compatible = "ti,lp8557", },
519 { }
520 };
521 MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
522
523 static const struct i2c_device_id lp855x_ids[] = {
524 {"lp8550", LP8550},
525 {"lp8551", LP8551},
526 {"lp8552", LP8552},
527 {"lp8553", LP8553},
528 {"lp8555", LP8555},
529 {"lp8556", LP8556},
530 {"lp8557", LP8557},
531 { }
532 };
533 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
534
535 static struct i2c_driver lp855x_driver = {
536 .driver = {
537 .name = "lp855x",
538 .of_match_table = of_match_ptr(lp855x_dt_ids),
539 },
540 .probe = lp855x_probe,
541 .remove = lp855x_remove,
542 .id_table = lp855x_ids,
543 };
544
545 module_i2c_driver(lp855x_driver);
546
547 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
548 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
549 MODULE_LICENSE("GPL");
550
