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