1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * aw99706 - Backlight driver for the AWINIC AW99706
4 *
5 * Copyright (C) 2025 Junjie Cao <caojunjie650@gmail.com>
6 * Copyright (C) 2025 Pengyu Luo <mitltlatltl@gmail.com>
7 *
8 * Based on vendor driver:
9 * Copyright (c) 2023 AWINIC Technology CO., LTD
10 */
11
12 #include <linux/backlight.h>
13 #include <linux/bitfield.h>
14 #include <linux/delay.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/i2c.h>
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/regmap.h>
20
21 #define AW99706_MAX_BRT_LVL 4095
22 #define AW99706_REG_MAX 0x1F
23 #define AW99706_ID 0x07
24
25 /* registers list */
26 #define AW99706_CFG0_REG 0x00
27 #define AW99706_DIM_MODE_MASK GENMASK(1, 0)
28
29 #define AW99706_CFG1_REG 0x01
30 #define AW99706_SW_FREQ_MASK GENMASK(3, 0)
31 #define AW99706_SW_ILMT_MASK GENMASK(5, 4)
32
33 #define AW99706_CFG2_REG 0x02
34 #define AW99706_ILED_MAX_MASK GENMASK(6, 0)
35 #define AW99706_UVLOSEL_MASK BIT(7)
36
37 #define AW99706_CFG3_REG 0x03
38 #define AW99706_CFG4_REG 0x04
39 #define AW99706_BRT_MSB_MASK GENMASK(3, 0)
40
41 #define AW99706_CFG5_REG 0x05
42 #define AW99706_BRT_LSB_MASK GENMASK(7, 0)
43
44 #define AW99706_CFG6_REG 0x06
45 #define AW99706_RAMP_CTL_MASK GENMASK(7, 6)
46
47 #define AW99706_CFG7_REG 0x07
48 #define AW99706_CFG8_REG 0x08
49 #define AW99706_CFG9_REG 0x09
50 #define AW99706_CFGA_REG 0x0A
51 #define AW99706_CFGB_REG 0x0B
52 #define AW99706_CFGC_REG 0x0C
53 #define AW99706_CFGD_REG 0x0D
54 #define AW99706_FLAG_REG 0x10
55 #define AW99706_BACKLIGHT_EN_MASK BIT(7)
56
57 #define AW99706_CHIPID_REG 0x11
58 #define AW99706_LED_OPEN_FLAG_REG 0x12
59 #define AW99706_LED_SHORT_FLAG_REG 0x13
60 #define AW99706_MTPLDOSEL_REG 0x1E
61 #define AW99706_MTPRUN_REG 0x1F
62
63 #define RESV U32_MAX
64
65 /* Boost switching frequency table, in Hz */
66 static const u32 aw99706_sw_freq_tbl[] = {
67 RESV, RESV, RESV, RESV, 300000, 400000, 500000, 600000,
68 660000, 750000, 850000, 1000000, 1200000, 1330000, 1500000, 1700000
69 };
70
71 /* Switching current limitation table, in uA */
72 static const u32 aw99706_sw_ilmt_tbl[] = {
73 1500000, 2000000, 2500000, 3000000
74 };
75
76 /* ULVO threshold table, in uV */
77 static const u32 aw99706_ulvo_thres_tbl[] = {
78 2200000, 5000000
79 };
80
81 struct aw99706_dt_prop {
82 const char * const name;
83 int (*lookup)(const struct aw99706_dt_prop *prop, u32 dt_val, u8 *val);
84 const u32 * const lookup_tbl;
85 u8 tbl_size;
86 u8 reg;
87 u8 mask;
88 u32 def_val;
89 };
90
aw99706_dt_property_lookup(const struct aw99706_dt_prop * prop,u32 dt_val,u8 * val)91 static int aw99706_dt_property_lookup(const struct aw99706_dt_prop *prop,
92 u32 dt_val, u8 *val)
93 {
94 int i;
95
96 if (!prop->lookup_tbl) {
97 if (dt_val > (prop->mask >> __ffs(prop->mask)))
98 return -EINVAL;
99 *val = dt_val;
100 return 0;
101 }
102
103 for (i = 0; i < prop->tbl_size; i++)
104 if (prop->lookup_tbl[i] != RESV && prop->lookup_tbl[i] == dt_val)
105 break;
106
107 *val = i;
108
109 return i == prop->tbl_size ? -EINVAL : 0;
110 }
111
112 #define MIN_ILED_MAX 5000
113 #define MAX_ILED_MAX 50000
114 #define STEP_ILED_MAX 500
115
116 static int
aw99706_dt_property_iled_max_convert(const struct aw99706_dt_prop * prop,u32 dt_val,u8 * val)117 aw99706_dt_property_iled_max_convert(const struct aw99706_dt_prop *prop,
118 u32 dt_val, u8 *val)
119 {
120 if (dt_val > MAX_ILED_MAX || dt_val < MIN_ILED_MAX)
121 return -EINVAL;
122
123 if ((dt_val - MIN_ILED_MAX) % STEP_ILED_MAX)
124 return -EINVAL;
125
126 *val = (dt_val - MIN_ILED_MAX) / STEP_ILED_MAX;
127
128 return 0;
129 }
130
131 static const struct aw99706_dt_prop aw99706_dt_props[] = {
132 {
133 "awinic,dim-mode", aw99706_dt_property_lookup,
134 NULL, 0,
135 AW99706_CFG0_REG, AW99706_DIM_MODE_MASK, 1,
136 },
137 {
138 "awinic,sw-freq-hz", aw99706_dt_property_lookup,
139 aw99706_sw_freq_tbl, ARRAY_SIZE(aw99706_sw_freq_tbl),
140 AW99706_CFG1_REG, AW99706_SW_FREQ_MASK, 750000,
141 },
142 {
143 "awinic,sw-ilmt-microamp", aw99706_dt_property_lookup,
144 aw99706_sw_ilmt_tbl, ARRAY_SIZE(aw99706_sw_ilmt_tbl),
145 AW99706_CFG1_REG, AW99706_SW_ILMT_MASK, 3000000,
146 },
147 {
148 "awinic,iled-max-microamp", aw99706_dt_property_iled_max_convert,
149 NULL, 0,
150 AW99706_CFG2_REG, AW99706_ILED_MAX_MASK, 20000,
151
152 },
153 {
154 "awinic,uvlo-thres-microvolt", aw99706_dt_property_lookup,
155 aw99706_ulvo_thres_tbl, ARRAY_SIZE(aw99706_ulvo_thres_tbl),
156 AW99706_CFG2_REG, AW99706_UVLOSEL_MASK, 2200000,
157 },
158 {
159 "awinic,ramp-ctl", aw99706_dt_property_lookup,
160 NULL, 0,
161 AW99706_CFG6_REG, AW99706_RAMP_CTL_MASK, 2,
162 }
163 };
164
165 struct reg_init_data {
166 u8 reg;
167 u8 mask;
168 u8 val;
169 };
170
171 struct aw99706_device {
172 struct i2c_client *client;
173 struct device *dev;
174 struct regmap *regmap;
175 struct backlight_device *bl_dev;
176 struct gpio_desc *hwen_gpio;
177 struct reg_init_data init_tbl[ARRAY_SIZE(aw99706_dt_props)];
178 bool bl_enable;
179 };
180
181 enum reg_access {
182 REG_NONE_ACCESS = 0,
183 REG_RD_ACCESS = 1,
184 REG_WR_ACCESS = 2,
185 };
186
187 static const u8 aw99706_regs[AW99706_REG_MAX + 1] = {
188 [AW99706_CFG0_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
189 [AW99706_CFG1_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
190 [AW99706_CFG2_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
191 [AW99706_CFG3_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
192 [AW99706_CFG4_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
193 [AW99706_CFG5_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
194 [AW99706_CFG6_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
195 [AW99706_CFG7_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
196 [AW99706_CFG8_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
197 [AW99706_CFG9_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
198 [AW99706_CFGA_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
199 [AW99706_CFGB_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
200 [AW99706_CFGC_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
201 [AW99706_CFGD_REG] = REG_RD_ACCESS | REG_WR_ACCESS,
202 [AW99706_FLAG_REG] = REG_RD_ACCESS,
203 [AW99706_CHIPID_REG] = REG_RD_ACCESS,
204 [AW99706_LED_OPEN_FLAG_REG] = REG_RD_ACCESS,
205 [AW99706_LED_SHORT_FLAG_REG] = REG_RD_ACCESS,
206
207 /*
208 * Write bit is dropped here, writing BIT(0) to MTPLDOSEL will unlock
209 * Multi-time Programmable (MTP).
210 */
211 [AW99706_MTPLDOSEL_REG] = REG_RD_ACCESS,
212 [AW99706_MTPRUN_REG] = REG_NONE_ACCESS,
213 };
214
aw99706_readable_reg(struct device * dev,unsigned int reg)215 static bool aw99706_readable_reg(struct device *dev, unsigned int reg)
216 {
217 return aw99706_regs[reg] & REG_RD_ACCESS;
218 }
219
aw99706_writeable_reg(struct device * dev,unsigned int reg)220 static bool aw99706_writeable_reg(struct device *dev, unsigned int reg)
221 {
222 return aw99706_regs[reg] & REG_WR_ACCESS;
223 }
224
aw99706_i2c_read(struct aw99706_device * aw,u8 reg,unsigned int * val)225 static inline int aw99706_i2c_read(struct aw99706_device *aw, u8 reg,
226 unsigned int *val)
227 {
228 return regmap_read(aw->regmap, reg, val);
229 }
230
aw99706_i2c_write(struct aw99706_device * aw,u8 reg,u8 val)231 static inline int aw99706_i2c_write(struct aw99706_device *aw, u8 reg, u8 val)
232 {
233 return regmap_write(aw->regmap, reg, val);
234 }
235
aw99706_i2c_update_bits(struct aw99706_device * aw,u8 reg,u8 mask,u8 val)236 static inline int aw99706_i2c_update_bits(struct aw99706_device *aw, u8 reg,
237 u8 mask, u8 val)
238 {
239 return regmap_update_bits(aw->regmap, reg, mask, val);
240 }
241
aw99706_dt_parse(struct aw99706_device * aw,struct backlight_properties * bl_props)242 static void aw99706_dt_parse(struct aw99706_device *aw,
243 struct backlight_properties *bl_props)
244 {
245 const struct aw99706_dt_prop *prop;
246 u32 dt_val;
247 int ret, i;
248 u8 val;
249
250 for (i = 0; i < ARRAY_SIZE(aw99706_dt_props); i++) {
251 prop = &aw99706_dt_props[i];
252 ret = device_property_read_u32(aw->dev, prop->name, &dt_val);
253 if (ret < 0)
254 dt_val = prop->def_val;
255
256 if (prop->lookup(prop, dt_val, &val)) {
257 dev_warn(aw->dev, "invalid value %d for property %s, using default value %d\n",
258 dt_val, prop->name, prop->def_val);
259
260 prop->lookup(prop, prop->def_val, &val);
261 }
262
263 aw->init_tbl[i].reg = prop->reg;
264 aw->init_tbl[i].mask = prop->mask;
265 aw->init_tbl[i].val = val << __ffs(prop->mask);
266 }
267
268 bl_props->brightness = AW99706_MAX_BRT_LVL >> 1;
269 bl_props->max_brightness = AW99706_MAX_BRT_LVL;
270 device_property_read_u32(aw->dev, "default-brightness",
271 &bl_props->brightness);
272 device_property_read_u32(aw->dev, "max-brightness",
273 &bl_props->max_brightness);
274
275 if (bl_props->max_brightness > AW99706_MAX_BRT_LVL)
276 bl_props->max_brightness = AW99706_MAX_BRT_LVL;
277
278 if (bl_props->brightness > bl_props->max_brightness)
279 bl_props->brightness = bl_props->max_brightness;
280 }
281
aw99706_hw_init(struct aw99706_device * aw)282 static int aw99706_hw_init(struct aw99706_device *aw)
283 {
284 int ret, i;
285
286 gpiod_set_value_cansleep(aw->hwen_gpio, 1);
287
288 for (i = 0; i < ARRAY_SIZE(aw->init_tbl); i++) {
289 ret = aw99706_i2c_update_bits(aw, aw->init_tbl[i].reg,
290 aw->init_tbl[i].mask,
291 aw->init_tbl[i].val);
292 if (ret < 0) {
293 dev_err(aw->dev, "Failed to write init data %d\n", ret);
294 return ret;
295 }
296 }
297
298 return 0;
299 }
300
aw99706_bl_enable(struct aw99706_device * aw,bool en)301 static int aw99706_bl_enable(struct aw99706_device *aw, bool en)
302 {
303 int ret;
304 u8 val;
305
306 val = FIELD_PREP(AW99706_BACKLIGHT_EN_MASK, en);
307 ret = aw99706_i2c_update_bits(aw, AW99706_CFGD_REG,
308 AW99706_BACKLIGHT_EN_MASK, val);
309 if (ret)
310 dev_err(aw->dev, "Failed to enable backlight!\n");
311
312 return ret;
313 }
314
aw99706_update_brightness(struct aw99706_device * aw,u32 brt_lvl)315 static int aw99706_update_brightness(struct aw99706_device *aw, u32 brt_lvl)
316 {
317 bool bl_enable_now = !!brt_lvl;
318 int ret;
319
320 ret = aw99706_i2c_write(aw, AW99706_CFG4_REG,
321 (brt_lvl >> 8) & AW99706_BRT_MSB_MASK);
322 if (ret < 0)
323 return ret;
324
325 ret = aw99706_i2c_write(aw, AW99706_CFG5_REG,
326 brt_lvl & AW99706_BRT_LSB_MASK);
327 if (ret < 0)
328 return ret;
329
330 if (aw->bl_enable != bl_enable_now) {
331 ret = aw99706_bl_enable(aw, bl_enable_now);
332 if (!ret)
333 aw->bl_enable = bl_enable_now;
334 }
335
336 return ret;
337 }
338
aw99706_bl_update_status(struct backlight_device * bl)339 static int aw99706_bl_update_status(struct backlight_device *bl)
340 {
341 struct aw99706_device *aw = bl_get_data(bl);
342
343 return aw99706_update_brightness(aw, backlight_get_brightness(bl));
344 }
345
346 static const struct backlight_ops aw99706_bl_ops = {
347 .options = BL_CORE_SUSPENDRESUME,
348 .update_status = aw99706_bl_update_status,
349 };
350
351 static const struct regmap_config aw99706_regmap_config = {
352 .reg_bits = 8,
353 .val_bits = 8,
354 .max_register = AW99706_REG_MAX,
355 .writeable_reg = aw99706_writeable_reg,
356 .readable_reg = aw99706_readable_reg,
357 };
358
aw99706_chip_id_read(struct aw99706_device * aw)359 static int aw99706_chip_id_read(struct aw99706_device *aw)
360 {
361 int ret;
362 unsigned int val;
363
364 ret = aw99706_i2c_read(aw, AW99706_CHIPID_REG, &val);
365 if (ret < 0)
366 return ret;
367
368 return val;
369 }
370
aw99706_probe(struct i2c_client * client)371 static int aw99706_probe(struct i2c_client *client)
372 {
373 struct device *dev = &client->dev;
374 struct aw99706_device *aw;
375 struct backlight_device *bl_dev;
376 struct backlight_properties props = {};
377 int ret = 0;
378
379 aw = devm_kzalloc(dev, sizeof(*aw), GFP_KERNEL);
380 if (!aw)
381 return -ENOMEM;
382
383 aw->client = client;
384 aw->dev = dev;
385 i2c_set_clientdata(client, aw);
386
387 aw->regmap = devm_regmap_init_i2c(client, &aw99706_regmap_config);
388 if (IS_ERR(aw->regmap))
389 return dev_err_probe(dev, PTR_ERR(aw->regmap),
390 "Failed to init regmap\n");
391
392 ret = aw99706_chip_id_read(aw);
393 if (ret != AW99706_ID)
394 return dev_err_probe(dev, -ENODEV,
395 "Unknown chip id 0x%02x\n", ret);
396
397 aw99706_dt_parse(aw, &props);
398
399 aw->hwen_gpio = devm_gpiod_get(aw->dev, "enable", GPIOD_OUT_LOW);
400 if (IS_ERR(aw->hwen_gpio))
401 return dev_err_probe(dev, PTR_ERR(aw->hwen_gpio),
402 "Failed to get enable gpio\n");
403
404 ret = aw99706_hw_init(aw);
405 if (ret < 0)
406 return dev_err_probe(dev, ret,
407 "Failed to initialize the chip\n");
408
409 props.type = BACKLIGHT_RAW;
410 props.scale = BACKLIGHT_SCALE_LINEAR;
411
412 bl_dev = devm_backlight_device_register(dev, "aw99706-backlight", dev,
413 aw, &aw99706_bl_ops, &props);
414 if (IS_ERR(bl_dev))
415 return dev_err_probe(dev, PTR_ERR(bl_dev),
416 "Failed to register backlight!\n");
417
418 aw->bl_dev = bl_dev;
419
420 return 0;
421 }
422
aw99706_remove(struct i2c_client * client)423 static void aw99706_remove(struct i2c_client *client)
424 {
425 struct aw99706_device *aw = i2c_get_clientdata(client);
426
427 aw99706_update_brightness(aw, 0);
428
429 msleep(50);
430
431 gpiod_set_value_cansleep(aw->hwen_gpio, 0);
432 }
433
aw99706_suspend(struct device * dev)434 static int aw99706_suspend(struct device *dev)
435 {
436 struct aw99706_device *aw = dev_get_drvdata(dev);
437
438 return aw99706_update_brightness(aw, 0);
439 }
440
aw99706_resume(struct device * dev)441 static int aw99706_resume(struct device *dev)
442 {
443 struct aw99706_device *aw = dev_get_drvdata(dev);
444
445 return aw99706_hw_init(aw);
446 }
447
448 static DEFINE_SIMPLE_DEV_PM_OPS(aw99706_pm_ops, aw99706_suspend, aw99706_resume);
449
450 static const struct i2c_device_id aw99706_ids[] = {
451 { .name = "aw99706" },
452 { }
453 };
454 MODULE_DEVICE_TABLE(i2c, aw99706_ids);
455
456 static const struct of_device_id aw99706_match_table[] = {
457 { .compatible = "awinic,aw99706", },
458 { }
459 };
460 MODULE_DEVICE_TABLE(of, aw99706_match_table);
461
462 static struct i2c_driver aw99706_i2c_driver = {
463 .probe = aw99706_probe,
464 .remove = aw99706_remove,
465 .id_table = aw99706_ids,
466 .driver = {
467 .name = "aw99706",
468 .of_match_table = aw99706_match_table,
469 .pm = pm_ptr(&aw99706_pm_ops),
470 },
471 };
472
473 module_i2c_driver(aw99706_i2c_driver);
474
475 MODULE_LICENSE("GPL v2");
476 MODULE_DESCRIPTION("BackLight driver for aw99706");
477