1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2011 ST-Ericsson SA.
4 * Copyright (C) 2009 Motorola, Inc.
5 *
6 * Simple driver for National Semiconductor LM3530 Backlight driver chip
7 *
8 * Author: Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>
9 * based on leds-lm3530.c by Dan Murphy <D.Murphy@motorola.com>
10 */
11
12 #include <linux/i2c.h>
13 #include <linux/leds.h>
14 #include <linux/slab.h>
15 #include <linux/platform_device.h>
16 #include <linux/input.h>
17 #include <linux/led-lm3530.h>
18 #include <linux/types.h>
19 #include <linux/regulator/consumer.h>
20 #include <linux/module.h>
21
22 #define LM3530_LED_DEV "lcd-backlight"
23 #define LM3530_NAME "lm3530-led"
24
25 #define LM3530_GEN_CONFIG 0x10
26 #define LM3530_ALS_CONFIG 0x20
27 #define LM3530_BRT_RAMP_RATE 0x30
28 #define LM3530_ALS_IMP_SELECT 0x41
29 #define LM3530_BRT_CTRL_REG 0xA0
30 #define LM3530_ALS_ZB0_REG 0x60
31 #define LM3530_ALS_ZB1_REG 0x61
32 #define LM3530_ALS_ZB2_REG 0x62
33 #define LM3530_ALS_ZB3_REG 0x63
34 #define LM3530_ALS_Z0T_REG 0x70
35 #define LM3530_ALS_Z1T_REG 0x71
36 #define LM3530_ALS_Z2T_REG 0x72
37 #define LM3530_ALS_Z3T_REG 0x73
38 #define LM3530_ALS_Z4T_REG 0x74
39 #define LM3530_REG_MAX 14
40
41 /* General Control Register */
42 #define LM3530_EN_I2C_SHIFT (0)
43 #define LM3530_RAMP_LAW_SHIFT (1)
44 #define LM3530_MAX_CURR_SHIFT (2)
45 #define LM3530_EN_PWM_SHIFT (5)
46 #define LM3530_PWM_POL_SHIFT (6)
47 #define LM3530_EN_PWM_SIMPLE_SHIFT (7)
48
49 #define LM3530_ENABLE_I2C (1 << LM3530_EN_I2C_SHIFT)
50 #define LM3530_ENABLE_PWM (1 << LM3530_EN_PWM_SHIFT)
51 #define LM3530_POL_LOW (1 << LM3530_PWM_POL_SHIFT)
52 #define LM3530_ENABLE_PWM_SIMPLE (1 << LM3530_EN_PWM_SIMPLE_SHIFT)
53
54 /* ALS Config Register Options */
55 #define LM3530_ALS_AVG_TIME_SHIFT (0)
56 #define LM3530_EN_ALS_SHIFT (3)
57 #define LM3530_ALS_SEL_SHIFT (5)
58
59 #define LM3530_ENABLE_ALS (3 << LM3530_EN_ALS_SHIFT)
60
61 /* Brightness Ramp Rate Register */
62 #define LM3530_BRT_RAMP_FALL_SHIFT (0)
63 #define LM3530_BRT_RAMP_RISE_SHIFT (3)
64
65 /* ALS Resistor Select */
66 #define LM3530_ALS1_IMP_SHIFT (0)
67 #define LM3530_ALS2_IMP_SHIFT (4)
68
69 /* Zone Boundary Register defaults */
70 #define LM3530_ALS_ZB_MAX (4)
71 #define LM3530_ALS_WINDOW_mV (1000)
72 #define LM3530_ALS_OFFSET_mV (4)
73
74 /* Zone Target Register defaults */
75 #define LM3530_DEF_ZT_0 (0x7F)
76 #define LM3530_DEF_ZT_1 (0x66)
77 #define LM3530_DEF_ZT_2 (0x4C)
78 #define LM3530_DEF_ZT_3 (0x33)
79 #define LM3530_DEF_ZT_4 (0x19)
80
81 /* 7 bits are used for the brightness : LM3530_BRT_CTRL_REG */
82 #define MAX_BRIGHTNESS (127)
83
84 struct lm3530_mode_map {
85 const char *mode;
86 enum lm3530_mode mode_val;
87 };
88
89 static struct lm3530_mode_map mode_map[] = {
90 { "man", LM3530_BL_MODE_MANUAL },
91 { "als", LM3530_BL_MODE_ALS },
92 { "pwm", LM3530_BL_MODE_PWM },
93 };
94
95 /**
96 * struct lm3530_data
97 * @led_dev: led class device
98 * @client: i2c client
99 * @pdata: LM3530 platform data
100 * @mode: mode of operation - manual, ALS, PWM
101 * @regulator: regulator
102 * @brighness: previous brightness value
103 * @enable: regulator is enabled
104 */
105 struct lm3530_data {
106 struct led_classdev led_dev;
107 struct i2c_client *client;
108 struct lm3530_platform_data *pdata;
109 enum lm3530_mode mode;
110 struct regulator *regulator;
111 enum led_brightness brightness;
112 bool enable;
113 };
114
115 /*
116 * struct lm3530_als_data
117 * @config : value of ALS configuration register
118 * @imp_sel : value of ALS resistor select register
119 * @zone : values of ALS ZB(Zone Boundary) registers
120 */
121 struct lm3530_als_data {
122 u8 config;
123 u8 imp_sel;
124 u8 zones[LM3530_ALS_ZB_MAX];
125 };
126
127 static const u8 lm3530_reg[LM3530_REG_MAX] = {
128 LM3530_GEN_CONFIG,
129 LM3530_ALS_CONFIG,
130 LM3530_BRT_RAMP_RATE,
131 LM3530_ALS_IMP_SELECT,
132 LM3530_BRT_CTRL_REG,
133 LM3530_ALS_ZB0_REG,
134 LM3530_ALS_ZB1_REG,
135 LM3530_ALS_ZB2_REG,
136 LM3530_ALS_ZB3_REG,
137 LM3530_ALS_Z0T_REG,
138 LM3530_ALS_Z1T_REG,
139 LM3530_ALS_Z2T_REG,
140 LM3530_ALS_Z3T_REG,
141 LM3530_ALS_Z4T_REG,
142 };
143
lm3530_get_mode_from_str(const char * str)144 static int lm3530_get_mode_from_str(const char *str)
145 {
146 int i;
147
148 for (i = 0; i < ARRAY_SIZE(mode_map); i++)
149 if (sysfs_streq(str, mode_map[i].mode))
150 return mode_map[i].mode_val;
151
152 return -EINVAL;
153 }
154
lm3530_als_configure(struct lm3530_platform_data * pdata,struct lm3530_als_data * als)155 static void lm3530_als_configure(struct lm3530_platform_data *pdata,
156 struct lm3530_als_data *als)
157 {
158 int i;
159 u32 als_vmin, als_vmax, als_vstep;
160
161 if (pdata->als_vmax == 0) {
162 pdata->als_vmin = 0;
163 pdata->als_vmax = LM3530_ALS_WINDOW_mV;
164 }
165
166 als_vmin = pdata->als_vmin;
167 als_vmax = pdata->als_vmax;
168
169 if ((als_vmax - als_vmin) > LM3530_ALS_WINDOW_mV)
170 pdata->als_vmax = als_vmax = als_vmin + LM3530_ALS_WINDOW_mV;
171
172 /* n zone boundary makes n+1 zones */
173 als_vstep = (als_vmax - als_vmin) / (LM3530_ALS_ZB_MAX + 1);
174
175 for (i = 0; i < LM3530_ALS_ZB_MAX; i++)
176 als->zones[i] = (((als_vmin + LM3530_ALS_OFFSET_mV) +
177 als_vstep + (i * als_vstep)) * LED_FULL) / 1000;
178
179 als->config =
180 (pdata->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) |
181 (LM3530_ENABLE_ALS) |
182 (pdata->als_input_mode << LM3530_ALS_SEL_SHIFT);
183
184 als->imp_sel =
185 (pdata->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) |
186 (pdata->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT);
187 }
188
lm3530_led_enable(struct lm3530_data * drvdata)189 static int lm3530_led_enable(struct lm3530_data *drvdata)
190 {
191 int ret;
192
193 if (drvdata->enable)
194 return 0;
195
196 ret = regulator_enable(drvdata->regulator);
197 if (ret) {
198 dev_err(drvdata->led_dev.dev, "Failed to enable vin:%d\n", ret);
199 return ret;
200 }
201
202 drvdata->enable = true;
203 return 0;
204 }
205
lm3530_led_disable(struct lm3530_data * drvdata)206 static void lm3530_led_disable(struct lm3530_data *drvdata)
207 {
208 int ret;
209
210 if (!drvdata->enable)
211 return;
212
213 ret = regulator_disable(drvdata->regulator);
214 if (ret) {
215 dev_err(drvdata->led_dev.dev, "Failed to disable vin:%d\n",
216 ret);
217 return;
218 }
219
220 drvdata->enable = false;
221 }
222
lm3530_init_registers(struct lm3530_data * drvdata)223 static int lm3530_init_registers(struct lm3530_data *drvdata)
224 {
225 int ret = 0;
226 int i;
227 u8 gen_config;
228 u8 brt_ramp;
229 u8 brightness;
230 u8 reg_val[LM3530_REG_MAX];
231 struct lm3530_platform_data *pdata = drvdata->pdata;
232 struct i2c_client *client = drvdata->client;
233 struct lm3530_pwm_data *pwm = &pdata->pwm_data;
234 struct lm3530_als_data als;
235
236 memset(&als, 0, sizeof(struct lm3530_als_data));
237
238 gen_config = (pdata->brt_ramp_law << LM3530_RAMP_LAW_SHIFT) |
239 ((pdata->max_current & 7) << LM3530_MAX_CURR_SHIFT);
240
241 switch (drvdata->mode) {
242 case LM3530_BL_MODE_MANUAL:
243 gen_config |= LM3530_ENABLE_I2C;
244 break;
245 case LM3530_BL_MODE_ALS:
246 gen_config |= LM3530_ENABLE_I2C;
247 lm3530_als_configure(pdata, &als);
248 break;
249 case LM3530_BL_MODE_PWM:
250 gen_config |= LM3530_ENABLE_PWM | LM3530_ENABLE_PWM_SIMPLE |
251 (pdata->pwm_pol_hi << LM3530_PWM_POL_SHIFT);
252 break;
253 }
254
255 brt_ramp = (pdata->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) |
256 (pdata->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT);
257
258 if (drvdata->brightness)
259 brightness = drvdata->brightness;
260 else
261 brightness = drvdata->brightness = pdata->brt_val;
262
263 if (brightness > drvdata->led_dev.max_brightness)
264 brightness = drvdata->led_dev.max_brightness;
265
266 reg_val[0] = gen_config; /* LM3530_GEN_CONFIG */
267 reg_val[1] = als.config; /* LM3530_ALS_CONFIG */
268 reg_val[2] = brt_ramp; /* LM3530_BRT_RAMP_RATE */
269 reg_val[3] = als.imp_sel; /* LM3530_ALS_IMP_SELECT */
270 reg_val[4] = brightness; /* LM3530_BRT_CTRL_REG */
271 reg_val[5] = als.zones[0]; /* LM3530_ALS_ZB0_REG */
272 reg_val[6] = als.zones[1]; /* LM3530_ALS_ZB1_REG */
273 reg_val[7] = als.zones[2]; /* LM3530_ALS_ZB2_REG */
274 reg_val[8] = als.zones[3]; /* LM3530_ALS_ZB3_REG */
275 reg_val[9] = LM3530_DEF_ZT_0; /* LM3530_ALS_Z0T_REG */
276 reg_val[10] = LM3530_DEF_ZT_1; /* LM3530_ALS_Z1T_REG */
277 reg_val[11] = LM3530_DEF_ZT_2; /* LM3530_ALS_Z2T_REG */
278 reg_val[12] = LM3530_DEF_ZT_3; /* LM3530_ALS_Z3T_REG */
279 reg_val[13] = LM3530_DEF_ZT_4; /* LM3530_ALS_Z4T_REG */
280
281 ret = lm3530_led_enable(drvdata);
282 if (ret)
283 return ret;
284
285 for (i = 0; i < LM3530_REG_MAX; i++) {
286 /* do not update brightness register when pwm mode */
287 if (lm3530_reg[i] == LM3530_BRT_CTRL_REG &&
288 drvdata->mode == LM3530_BL_MODE_PWM) {
289 if (pwm->pwm_set_intensity)
290 pwm->pwm_set_intensity(reg_val[i],
291 drvdata->led_dev.max_brightness);
292 continue;
293 }
294
295 ret = i2c_smbus_write_byte_data(client,
296 lm3530_reg[i], reg_val[i]);
297 if (ret)
298 break;
299 }
300
301 return ret;
302 }
303
lm3530_brightness_set(struct led_classdev * led_cdev,enum led_brightness brt_val)304 static void lm3530_brightness_set(struct led_classdev *led_cdev,
305 enum led_brightness brt_val)
306 {
307 int err;
308 struct lm3530_data *drvdata =
309 container_of(led_cdev, struct lm3530_data, led_dev);
310 struct lm3530_platform_data *pdata = drvdata->pdata;
311 struct lm3530_pwm_data *pwm = &pdata->pwm_data;
312 u8 max_brightness = led_cdev->max_brightness;
313
314 switch (drvdata->mode) {
315 case LM3530_BL_MODE_MANUAL:
316
317 if (!drvdata->enable) {
318 err = lm3530_init_registers(drvdata);
319 if (err) {
320 dev_err(&drvdata->client->dev,
321 "Register Init failed: %d\n", err);
322 break;
323 }
324 }
325
326 /* set the brightness in brightness control register*/
327 err = i2c_smbus_write_byte_data(drvdata->client,
328 LM3530_BRT_CTRL_REG, brt_val);
329 if (err)
330 dev_err(&drvdata->client->dev,
331 "Unable to set brightness: %d\n", err);
332 else
333 drvdata->brightness = brt_val;
334
335 if (brt_val == 0)
336 lm3530_led_disable(drvdata);
337 break;
338 case LM3530_BL_MODE_ALS:
339 break;
340 case LM3530_BL_MODE_PWM:
341 if (pwm->pwm_set_intensity)
342 pwm->pwm_set_intensity(brt_val, max_brightness);
343 break;
344 default:
345 break;
346 }
347 }
348
lm3530_mode_get(struct device * dev,struct device_attribute * attr,char * buf)349 static ssize_t lm3530_mode_get(struct device *dev,
350 struct device_attribute *attr, char *buf)
351 {
352 struct led_classdev *led_cdev = dev_get_drvdata(dev);
353 struct lm3530_data *drvdata;
354 int i, len = 0;
355
356 drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
357 for (i = 0; i < ARRAY_SIZE(mode_map); i++)
358 if (drvdata->mode == mode_map[i].mode_val)
359 len += sprintf(buf + len, "[%s] ", mode_map[i].mode);
360 else
361 len += sprintf(buf + len, "%s ", mode_map[i].mode);
362
363 len += sprintf(buf + len, "\n");
364
365 return len;
366 }
367
lm3530_mode_set(struct device * dev,struct device_attribute * attr,const char * buf,size_t size)368 static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
369 *attr, const char *buf, size_t size)
370 {
371 struct led_classdev *led_cdev = dev_get_drvdata(dev);
372 struct lm3530_data *drvdata;
373 struct lm3530_pwm_data *pwm;
374 u8 max_brightness;
375 int mode, err;
376
377 drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
378 pwm = &drvdata->pdata->pwm_data;
379 max_brightness = led_cdev->max_brightness;
380 mode = lm3530_get_mode_from_str(buf);
381 if (mode < 0) {
382 dev_err(dev, "Invalid mode\n");
383 return mode;
384 }
385
386 drvdata->mode = mode;
387
388 /* set pwm to low if unnecessary */
389 if (mode != LM3530_BL_MODE_PWM && pwm->pwm_set_intensity)
390 pwm->pwm_set_intensity(0, max_brightness);
391
392 err = lm3530_init_registers(drvdata);
393 if (err) {
394 dev_err(dev, "Setting %s Mode failed :%d\n", buf, err);
395 return err;
396 }
397
398 return sizeof(drvdata->mode);
399 }
400 static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set);
401
402 static struct attribute *lm3530_attrs[] = {
403 &dev_attr_mode.attr,
404 NULL
405 };
406 ATTRIBUTE_GROUPS(lm3530);
407
lm3530_probe(struct i2c_client * client,const struct i2c_device_id * id)408 static int lm3530_probe(struct i2c_client *client,
409 const struct i2c_device_id *id)
410 {
411 struct lm3530_platform_data *pdata = dev_get_platdata(&client->dev);
412 struct lm3530_data *drvdata;
413 int err = 0;
414
415 if (pdata == NULL) {
416 dev_err(&client->dev, "platform data required\n");
417 return -ENODEV;
418 }
419
420 /* BL mode */
421 if (pdata->mode > LM3530_BL_MODE_PWM) {
422 dev_err(&client->dev, "Illegal Mode request\n");
423 return -EINVAL;
424 }
425
426 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
427 dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
428 return -EIO;
429 }
430
431 drvdata = devm_kzalloc(&client->dev, sizeof(struct lm3530_data),
432 GFP_KERNEL);
433 if (drvdata == NULL)
434 return -ENOMEM;
435
436 drvdata->mode = pdata->mode;
437 drvdata->client = client;
438 drvdata->pdata = pdata;
439 drvdata->brightness = LED_OFF;
440 drvdata->enable = false;
441 drvdata->led_dev.name = LM3530_LED_DEV;
442 drvdata->led_dev.brightness_set = lm3530_brightness_set;
443 drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
444 drvdata->led_dev.groups = lm3530_groups;
445
446 i2c_set_clientdata(client, drvdata);
447
448 drvdata->regulator = devm_regulator_get(&client->dev, "vin");
449 if (IS_ERR(drvdata->regulator)) {
450 dev_err(&client->dev, "regulator get failed\n");
451 err = PTR_ERR(drvdata->regulator);
452 drvdata->regulator = NULL;
453 return err;
454 }
455
456 if (drvdata->pdata->brt_val) {
457 err = lm3530_init_registers(drvdata);
458 if (err < 0) {
459 dev_err(&client->dev,
460 "Register Init failed: %d\n", err);
461 return err;
462 }
463 }
464 err = led_classdev_register(&client->dev, &drvdata->led_dev);
465 if (err < 0) {
466 dev_err(&client->dev, "Register led class failed: %d\n", err);
467 return err;
468 }
469
470 return 0;
471 }
472
lm3530_remove(struct i2c_client * client)473 static int lm3530_remove(struct i2c_client *client)
474 {
475 struct lm3530_data *drvdata = i2c_get_clientdata(client);
476
477 lm3530_led_disable(drvdata);
478 led_classdev_unregister(&drvdata->led_dev);
479 return 0;
480 }
481
482 static const struct i2c_device_id lm3530_id[] = {
483 {LM3530_NAME, 0},
484 {}
485 };
486 MODULE_DEVICE_TABLE(i2c, lm3530_id);
487
488 static struct i2c_driver lm3530_i2c_driver = {
489 .probe = lm3530_probe,
490 .remove = lm3530_remove,
491 .id_table = lm3530_id,
492 .driver = {
493 .name = LM3530_NAME,
494 },
495 };
496
497 module_i2c_driver(lm3530_i2c_driver);
498
499 MODULE_DESCRIPTION("Back Light driver for LM3530");
500 MODULE_LICENSE("GPL v2");
501 MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");
502
