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7be865ab KM |
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/err.h> | |
4add0664 | 17 | #include <linux/of.h> |
f7f95056 | 18 | #include <linux/platform_data/lp855x.h> |
8cc9764c | 19 | #include <linux/pwm.h> |
7be865ab | 20 | |
26e8ccc2 KM |
21 | /* LP8550/1/2/3/6 Registers */ |
22 | #define LP855X_BRIGHTNESS_CTRL 0x00 | |
23 | #define LP855X_DEVICE_CTRL 0x01 | |
24 | #define LP855X_EEPROM_START 0xA0 | |
25 | #define LP855X_EEPROM_END 0xA7 | |
26 | #define LP8556_EPROM_START 0xA0 | |
27 | #define LP8556_EPROM_END 0xAF | |
28 | ||
29 | /* LP8557 Registers */ | |
30 | #define LP8557_BL_CMD 0x00 | |
31 | #define LP8557_BL_MASK 0x01 | |
32 | #define LP8557_BL_ON 0x01 | |
33 | #define LP8557_BL_OFF 0x00 | |
34 | #define LP8557_BRIGHTNESS_CTRL 0x04 | |
35 | #define LP8557_CONFIG 0x10 | |
36 | #define LP8557_EPROM_START 0x10 | |
37 | #define LP8557_EPROM_END 0x1E | |
7be865ab | 38 | |
7be865ab KM |
39 | #define DEFAULT_BL_NAME "lcd-backlight" |
40 | #define MAX_BRIGHTNESS 255 | |
41 | ||
0b818573 KM |
42 | enum lp855x_brightness_ctrl_mode { |
43 | PWM_BASED = 1, | |
44 | REGISTER_BASED, | |
45 | }; | |
46 | ||
68853bc2 KM |
47 | struct lp855x; |
48 | ||
49 | /* | |
50 | * struct lp855x_device_config | |
51 | * @pre_init_device: init device function call before updating the brightness | |
52 | * @reg_brightness: register address for brigthenss control | |
53 | * @reg_devicectrl: register address for device control | |
54 | * @post_init_device: late init device function call | |
55 | */ | |
56 | struct lp855x_device_config { | |
57 | int (*pre_init_device)(struct lp855x *); | |
58 | u8 reg_brightness; | |
59 | u8 reg_devicectrl; | |
60 | int (*post_init_device)(struct lp855x *); | |
61 | }; | |
62 | ||
7be865ab KM |
63 | struct lp855x { |
64 | const char *chipname; | |
65 | enum lp855x_chip_id chip_id; | |
0b818573 | 66 | enum lp855x_brightness_ctrl_mode mode; |
68853bc2 | 67 | struct lp855x_device_config *cfg; |
7be865ab KM |
68 | struct i2c_client *client; |
69 | struct backlight_device *bl; | |
70 | struct device *dev; | |
7be865ab | 71 | struct lp855x_platform_data *pdata; |
8cc9764c | 72 | struct pwm_device *pwm; |
7be865ab KM |
73 | }; |
74 | ||
7be865ab KM |
75 | static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) |
76 | { | |
eaa4d02f | 77 | return i2c_smbus_write_byte_data(lp->client, reg, data); |
7be865ab KM |
78 | } |
79 | ||
26e8ccc2 KM |
80 | static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data) |
81 | { | |
82 | int ret; | |
83 | u8 tmp; | |
84 | ||
85 | ret = i2c_smbus_read_byte_data(lp->client, reg); | |
86 | if (ret < 0) { | |
87 | dev_err(lp->dev, "failed to read 0x%.2x\n", reg); | |
88 | return ret; | |
89 | } | |
90 | ||
91 | tmp = (u8)ret; | |
92 | tmp &= ~mask; | |
93 | tmp |= data & mask; | |
94 | ||
95 | return lp855x_write_byte(lp, reg, tmp); | |
96 | } | |
97 | ||
7be865ab KM |
98 | static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr) |
99 | { | |
100 | u8 start, end; | |
101 | ||
102 | switch (lp->chip_id) { | |
103 | case LP8550: | |
104 | case LP8551: | |
105 | case LP8552: | |
106 | case LP8553: | |
26e8ccc2 KM |
107 | start = LP855X_EEPROM_START; |
108 | end = LP855X_EEPROM_END; | |
7be865ab KM |
109 | break; |
110 | case LP8556: | |
26e8ccc2 KM |
111 | start = LP8556_EPROM_START; |
112 | end = LP8556_EPROM_END; | |
113 | break; | |
114 | case LP8557: | |
115 | start = LP8557_EPROM_START; | |
116 | end = LP8557_EPROM_END; | |
7be865ab KM |
117 | break; |
118 | default: | |
119 | return false; | |
120 | } | |
121 | ||
122 | return (addr >= start && addr <= end); | |
123 | } | |
124 | ||
26e8ccc2 KM |
125 | static int lp8557_bl_off(struct lp855x *lp) |
126 | { | |
127 | /* BL_ON = 0 before updating EPROM settings */ | |
128 | return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK, | |
129 | LP8557_BL_OFF); | |
130 | } | |
131 | ||
132 | static int lp8557_bl_on(struct lp855x *lp) | |
133 | { | |
134 | /* BL_ON = 1 after updating EPROM settings */ | |
135 | return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK, | |
136 | LP8557_BL_ON); | |
137 | } | |
138 | ||
68853bc2 | 139 | static struct lp855x_device_config lp855x_dev_cfg = { |
26e8ccc2 KM |
140 | .reg_brightness = LP855X_BRIGHTNESS_CTRL, |
141 | .reg_devicectrl = LP855X_DEVICE_CTRL, | |
142 | }; | |
143 | ||
144 | static struct lp855x_device_config lp8557_dev_cfg = { | |
145 | .reg_brightness = LP8557_BRIGHTNESS_CTRL, | |
146 | .reg_devicectrl = LP8557_CONFIG, | |
147 | .pre_init_device = lp8557_bl_off, | |
148 | .post_init_device = lp8557_bl_on, | |
68853bc2 KM |
149 | }; |
150 | ||
151 | /* | |
152 | * Device specific configuration flow | |
153 | * | |
154 | * a) pre_init_device(optional) | |
155 | * b) update the brightness register | |
156 | * c) update device control register | |
157 | * d) update ROM area(optional) | |
158 | * e) post_init_device(optional) | |
159 | * | |
160 | */ | |
161 | static int lp855x_configure(struct lp855x *lp) | |
7be865ab KM |
162 | { |
163 | u8 val, addr; | |
164 | int i, ret; | |
165 | struct lp855x_platform_data *pd = lp->pdata; | |
166 | ||
68853bc2 KM |
167 | switch (lp->chip_id) { |
168 | case LP8550 ... LP8556: | |
169 | lp->cfg = &lp855x_dev_cfg; | |
170 | break; | |
26e8ccc2 KM |
171 | case LP8557: |
172 | lp->cfg = &lp8557_dev_cfg; | |
173 | break; | |
68853bc2 KM |
174 | default: |
175 | return -EINVAL; | |
176 | } | |
177 | ||
178 | if (lp->cfg->pre_init_device) { | |
179 | ret = lp->cfg->pre_init_device(lp); | |
180 | if (ret) { | |
181 | dev_err(lp->dev, "pre init device err: %d\n", ret); | |
182 | goto err; | |
183 | } | |
184 | } | |
185 | ||
7be865ab | 186 | val = pd->initial_brightness; |
68853bc2 | 187 | ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val); |
7be865ab | 188 | if (ret) |
68853bc2 | 189 | goto err; |
7be865ab KM |
190 | |
191 | val = pd->device_control; | |
68853bc2 | 192 | ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val); |
7be865ab | 193 | if (ret) |
68853bc2 | 194 | goto err; |
7be865ab | 195 | |
c365e59d | 196 | if (pd->size_program > 0) { |
7be865ab KM |
197 | for (i = 0; i < pd->size_program; i++) { |
198 | addr = pd->rom_data[i].addr; | |
199 | val = pd->rom_data[i].val; | |
200 | if (!lp855x_is_valid_rom_area(lp, addr)) | |
201 | continue; | |
202 | ||
203 | ret = lp855x_write_byte(lp, addr, val); | |
204 | if (ret) | |
68853bc2 KM |
205 | goto err; |
206 | } | |
207 | } | |
208 | ||
209 | if (lp->cfg->post_init_device) { | |
210 | ret = lp->cfg->post_init_device(lp); | |
211 | if (ret) { | |
212 | dev_err(lp->dev, "post init device err: %d\n", ret); | |
213 | goto err; | |
7be865ab KM |
214 | } |
215 | } | |
216 | ||
68853bc2 KM |
217 | return 0; |
218 | ||
219 | err: | |
7be865ab KM |
220 | return ret; |
221 | } | |
222 | ||
8cc9764c KM |
223 | static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br) |
224 | { | |
225 | unsigned int period = lp->pdata->period_ns; | |
226 | unsigned int duty = br * period / max_br; | |
227 | struct pwm_device *pwm; | |
228 | ||
229 | /* request pwm device with the consumer name */ | |
230 | if (!lp->pwm) { | |
231 | pwm = devm_pwm_get(lp->dev, lp->chipname); | |
232 | if (IS_ERR(pwm)) | |
233 | return; | |
234 | ||
235 | lp->pwm = pwm; | |
236 | } | |
237 | ||
238 | pwm_config(lp->pwm, duty, period); | |
239 | if (duty) | |
240 | pwm_enable(lp->pwm); | |
241 | else | |
242 | pwm_disable(lp->pwm); | |
243 | } | |
244 | ||
7be865ab KM |
245 | static int lp855x_bl_update_status(struct backlight_device *bl) |
246 | { | |
247 | struct lp855x *lp = bl_get_data(bl); | |
7be865ab KM |
248 | |
249 | if (bl->props.state & BL_CORE_SUSPENDED) | |
250 | bl->props.brightness = 0; | |
251 | ||
0b818573 | 252 | if (lp->mode == PWM_BASED) { |
7be865ab KM |
253 | int br = bl->props.brightness; |
254 | int max_br = bl->props.max_brightness; | |
255 | ||
8cc9764c | 256 | lp855x_pwm_ctrl(lp, br, max_br); |
7be865ab | 257 | |
0b818573 | 258 | } else if (lp->mode == REGISTER_BASED) { |
7be865ab | 259 | u8 val = bl->props.brightness; |
26e8ccc2 | 260 | lp855x_write_byte(lp, lp->cfg->reg_brightness, val); |
7be865ab KM |
261 | } |
262 | ||
263 | return 0; | |
264 | } | |
265 | ||
266 | static int lp855x_bl_get_brightness(struct backlight_device *bl) | |
267 | { | |
7be865ab KM |
268 | return bl->props.brightness; |
269 | } | |
270 | ||
271 | static const struct backlight_ops lp855x_bl_ops = { | |
272 | .options = BL_CORE_SUSPENDRESUME, | |
273 | .update_status = lp855x_bl_update_status, | |
274 | .get_brightness = lp855x_bl_get_brightness, | |
275 | }; | |
276 | ||
277 | static int lp855x_backlight_register(struct lp855x *lp) | |
278 | { | |
279 | struct backlight_device *bl; | |
280 | struct backlight_properties props; | |
281 | struct lp855x_platform_data *pdata = lp->pdata; | |
600ffd33 | 282 | const char *name = pdata->name ? : DEFAULT_BL_NAME; |
7be865ab KM |
283 | |
284 | props.type = BACKLIGHT_PLATFORM; | |
285 | props.max_brightness = MAX_BRIGHTNESS; | |
286 | ||
287 | if (pdata->initial_brightness > props.max_brightness) | |
288 | pdata->initial_brightness = props.max_brightness; | |
289 | ||
290 | props.brightness = pdata->initial_brightness; | |
291 | ||
292 | bl = backlight_device_register(name, lp->dev, lp, | |
293 | &lp855x_bl_ops, &props); | |
294 | if (IS_ERR(bl)) | |
295 | return PTR_ERR(bl); | |
296 | ||
297 | lp->bl = bl; | |
298 | ||
299 | return 0; | |
300 | } | |
301 | ||
302 | static void lp855x_backlight_unregister(struct lp855x *lp) | |
303 | { | |
304 | if (lp->bl) | |
305 | backlight_device_unregister(lp->bl); | |
306 | } | |
307 | ||
308 | static ssize_t lp855x_get_chip_id(struct device *dev, | |
309 | struct device_attribute *attr, char *buf) | |
310 | { | |
311 | struct lp855x *lp = dev_get_drvdata(dev); | |
6a7aeb1a | 312 | return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname); |
7be865ab KM |
313 | } |
314 | ||
315 | static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, | |
316 | struct device_attribute *attr, char *buf) | |
317 | { | |
318 | struct lp855x *lp = dev_get_drvdata(dev); | |
7be865ab KM |
319 | char *strmode = NULL; |
320 | ||
0b818573 | 321 | if (lp->mode == PWM_BASED) |
7be865ab | 322 | strmode = "pwm based"; |
0b818573 | 323 | else if (lp->mode == REGISTER_BASED) |
7be865ab KM |
324 | strmode = "register based"; |
325 | ||
6a7aeb1a | 326 | return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); |
7be865ab KM |
327 | } |
328 | ||
329 | static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); | |
330 | static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); | |
331 | ||
332 | static struct attribute *lp855x_attributes[] = { | |
333 | &dev_attr_chip_id.attr, | |
334 | &dev_attr_bl_ctl_mode.attr, | |
335 | NULL, | |
336 | }; | |
337 | ||
338 | static const struct attribute_group lp855x_attr_group = { | |
339 | .attrs = lp855x_attributes, | |
340 | }; | |
341 | ||
4add0664 KM |
342 | #ifdef CONFIG_OF |
343 | static int lp855x_parse_dt(struct device *dev, struct device_node *node) | |
344 | { | |
345 | struct lp855x_platform_data *pdata; | |
346 | int rom_length; | |
347 | ||
348 | if (!node) { | |
349 | dev_err(dev, "no platform data\n"); | |
350 | return -EINVAL; | |
351 | } | |
352 | ||
353 | pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); | |
354 | if (!pdata) | |
355 | return -ENOMEM; | |
356 | ||
357 | of_property_read_string(node, "bl-name", &pdata->name); | |
358 | of_property_read_u8(node, "dev-ctrl", &pdata->device_control); | |
359 | of_property_read_u8(node, "init-brt", &pdata->initial_brightness); | |
360 | of_property_read_u32(node, "pwm-period", &pdata->period_ns); | |
361 | ||
362 | /* Fill ROM platform data if defined */ | |
363 | rom_length = of_get_child_count(node); | |
364 | if (rom_length > 0) { | |
365 | struct lp855x_rom_data *rom; | |
366 | struct device_node *child; | |
367 | int i = 0; | |
368 | ||
369 | rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL); | |
370 | if (!rom) | |
371 | return -ENOMEM; | |
372 | ||
373 | for_each_child_of_node(node, child) { | |
374 | of_property_read_u8(child, "rom-addr", &rom[i].addr); | |
375 | of_property_read_u8(child, "rom-val", &rom[i].val); | |
376 | i++; | |
377 | } | |
378 | ||
379 | pdata->size_program = rom_length; | |
380 | pdata->rom_data = &rom[0]; | |
381 | } | |
382 | ||
383 | dev->platform_data = pdata; | |
384 | ||
385 | return 0; | |
386 | } | |
387 | #else | |
388 | static int lp855x_parse_dt(struct device *dev, struct device_node *node) | |
389 | { | |
390 | return -EINVAL; | |
391 | } | |
392 | #endif | |
393 | ||
7be865ab KM |
394 | static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) |
395 | { | |
396 | struct lp855x *lp; | |
397 | struct lp855x_platform_data *pdata = cl->dev.platform_data; | |
4add0664 | 398 | struct device_node *node = cl->dev.of_node; |
7be865ab KM |
399 | int ret; |
400 | ||
401 | if (!pdata) { | |
4add0664 KM |
402 | ret = lp855x_parse_dt(&cl->dev, node); |
403 | if (ret < 0) | |
404 | return ret; | |
405 | ||
406 | pdata = cl->dev.platform_data; | |
7be865ab KM |
407 | } |
408 | ||
409 | if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) | |
410 | return -EIO; | |
411 | ||
412 | lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); | |
413 | if (!lp) | |
414 | return -ENOMEM; | |
415 | ||
0b818573 KM |
416 | if (pdata->period_ns > 0) |
417 | lp->mode = PWM_BASED; | |
418 | else | |
419 | lp->mode = REGISTER_BASED; | |
420 | ||
7be865ab KM |
421 | lp->client = cl; |
422 | lp->dev = &cl->dev; | |
423 | lp->pdata = pdata; | |
424 | lp->chipname = id->name; | |
425 | lp->chip_id = id->driver_data; | |
426 | i2c_set_clientdata(cl, lp); | |
427 | ||
68853bc2 | 428 | ret = lp855x_configure(lp); |
7be865ab | 429 | if (ret) { |
68853bc2 KM |
430 | dev_err(lp->dev, "device config err: %d", ret); |
431 | goto err_dev; | |
7be865ab KM |
432 | } |
433 | ||
434 | ret = lp855x_backlight_register(lp); | |
435 | if (ret) { | |
436 | dev_err(lp->dev, | |
437 | "failed to register backlight. err: %d\n", ret); | |
438 | goto err_dev; | |
439 | } | |
440 | ||
441 | ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); | |
442 | if (ret) { | |
443 | dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); | |
444 | goto err_sysfs; | |
445 | } | |
446 | ||
447 | backlight_update_status(lp->bl); | |
448 | return 0; | |
449 | ||
450 | err_sysfs: | |
451 | lp855x_backlight_unregister(lp); | |
452 | err_dev: | |
453 | return ret; | |
454 | } | |
455 | ||
7e4b9d0b | 456 | static int lp855x_remove(struct i2c_client *cl) |
7be865ab KM |
457 | { |
458 | struct lp855x *lp = i2c_get_clientdata(cl); | |
459 | ||
460 | lp->bl->props.brightness = 0; | |
461 | backlight_update_status(lp->bl); | |
462 | sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); | |
463 | lp855x_backlight_unregister(lp); | |
464 | ||
465 | return 0; | |
466 | } | |
467 | ||
4add0664 KM |
468 | static const struct of_device_id lp855x_dt_ids[] = { |
469 | { .compatible = "ti,lp8550", }, | |
470 | { .compatible = "ti,lp8551", }, | |
471 | { .compatible = "ti,lp8552", }, | |
472 | { .compatible = "ti,lp8553", }, | |
473 | { .compatible = "ti,lp8556", }, | |
474 | { .compatible = "ti,lp8557", }, | |
475 | { } | |
476 | }; | |
477 | MODULE_DEVICE_TABLE(of, lp855x_dt_ids); | |
478 | ||
7be865ab KM |
479 | static const struct i2c_device_id lp855x_ids[] = { |
480 | {"lp8550", LP8550}, | |
481 | {"lp8551", LP8551}, | |
482 | {"lp8552", LP8552}, | |
483 | {"lp8553", LP8553}, | |
484 | {"lp8556", LP8556}, | |
26e8ccc2 | 485 | {"lp8557", LP8557}, |
7be865ab KM |
486 | { } |
487 | }; | |
488 | MODULE_DEVICE_TABLE(i2c, lp855x_ids); | |
489 | ||
490 | static struct i2c_driver lp855x_driver = { | |
491 | .driver = { | |
492 | .name = "lp855x", | |
4add0664 | 493 | .of_match_table = of_match_ptr(lp855x_dt_ids), |
7be865ab KM |
494 | }, |
495 | .probe = lp855x_probe, | |
d1723fa2 | 496 | .remove = lp855x_remove, |
7be865ab KM |
497 | .id_table = lp855x_ids, |
498 | }; | |
499 | ||
500 | module_i2c_driver(lp855x_driver); | |
501 | ||
502 | MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); | |
503 | MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); | |
504 | MODULE_LICENSE("GPL"); |