1 /* Copyright (c) 2015, Sony Mobile Communications, AB.
2 *
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License version 2 and
5 * only version 2 as published by the Free Software Foundation.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
11 */
12
13 #include <linux/kernel.h>
14 #include <linux/backlight.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/regmap.h>
19
20 /* From DT binding */
21 #define PM8941_WLED_DEFAULT_BRIGHTNESS 2048
22
23 #define PM8941_WLED_REG_VAL_BASE 0x40
24 #define PM8941_WLED_REG_VAL_MAX 0xFFF
25
26 #define PM8941_WLED_REG_MOD_EN 0x46
27 #define PM8941_WLED_REG_MOD_EN_BIT BIT(7)
28 #define PM8941_WLED_REG_MOD_EN_MASK BIT(7)
29
30 #define PM8941_WLED_REG_SYNC 0x47
31 #define PM8941_WLED_REG_SYNC_MASK 0x07
32 #define PM8941_WLED_REG_SYNC_LED1 BIT(0)
33 #define PM8941_WLED_REG_SYNC_LED2 BIT(1)
34 #define PM8941_WLED_REG_SYNC_LED3 BIT(2)
35 #define PM8941_WLED_REG_SYNC_ALL 0x07
36 #define PM8941_WLED_REG_SYNC_CLEAR 0x00
37
38 #define PM8941_WLED_REG_FREQ 0x4c
39 #define PM8941_WLED_REG_FREQ_MASK 0x0f
40
41 #define PM8941_WLED_REG_OVP 0x4d
42 #define PM8941_WLED_REG_OVP_MASK 0x03
43
44 #define PM8941_WLED_REG_BOOST 0x4e
45 #define PM8941_WLED_REG_BOOST_MASK 0x07
46
47 #define PM8941_WLED_REG_SINK 0x4f
48 #define PM8941_WLED_REG_SINK_MASK 0xe0
49 #define PM8941_WLED_REG_SINK_SHFT 0x05
50
51 /* Per-'string' registers below */
52 #define PM8941_WLED_REG_STR_OFFSET 0x10
53
54 #define PM8941_WLED_REG_STR_MOD_EN_BASE 0x60
55 #define PM8941_WLED_REG_STR_MOD_MASK BIT(7)
56 #define PM8941_WLED_REG_STR_MOD_EN BIT(7)
57
58 #define PM8941_WLED_REG_STR_SCALE_BASE 0x62
59 #define PM8941_WLED_REG_STR_SCALE_MASK 0x1f
60
61 #define PM8941_WLED_REG_STR_MOD_SRC_BASE 0x63
62 #define PM8941_WLED_REG_STR_MOD_SRC_MASK 0x01
63 #define PM8941_WLED_REG_STR_MOD_SRC_INT 0x00
64 #define PM8941_WLED_REG_STR_MOD_SRC_EXT 0x01
65
66 #define PM8941_WLED_REG_STR_CABC_BASE 0x66
67 #define PM8941_WLED_REG_STR_CABC_MASK BIT(7)
68 #define PM8941_WLED_REG_STR_CABC_EN BIT(7)
69
70 struct pm8941_wled_config {
71 u32 i_boost_limit;
72 u32 ovp;
73 u32 switch_freq;
74 u32 num_strings;
75 u32 i_limit;
76 bool cs_out_en;
77 bool ext_gen;
78 bool cabc_en;
79 };
80
81 struct pm8941_wled {
82 const char *name;
83 struct regmap *regmap;
84 u16 addr;
85
86 struct pm8941_wled_config cfg;
87 };
88
pm8941_wled_update_status(struct backlight_device * bl)89 static int pm8941_wled_update_status(struct backlight_device *bl)
90 {
91 struct pm8941_wled *wled = bl_get_data(bl);
92 u16 val = bl->props.brightness;
93 u8 ctrl = 0;
94 int rc;
95 int i;
96
97 if (bl->props.power != FB_BLANK_UNBLANK ||
98 bl->props.fb_blank != FB_BLANK_UNBLANK ||
99 bl->props.state & BL_CORE_FBBLANK)
100 val = 0;
101
102 if (val != 0)
103 ctrl = PM8941_WLED_REG_MOD_EN_BIT;
104
105 rc = regmap_update_bits(wled->regmap,
106 wled->addr + PM8941_WLED_REG_MOD_EN,
107 PM8941_WLED_REG_MOD_EN_MASK, ctrl);
108 if (rc)
109 return rc;
110
111 for (i = 0; i < wled->cfg.num_strings; ++i) {
112 u8 v[2] = { val & 0xff, (val >> 8) & 0xf };
113
114 rc = regmap_bulk_write(wled->regmap,
115 wled->addr + PM8941_WLED_REG_VAL_BASE + 2 * i,
116 v, 2);
117 if (rc)
118 return rc;
119 }
120
121 rc = regmap_update_bits(wled->regmap,
122 wled->addr + PM8941_WLED_REG_SYNC,
123 PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_ALL);
124 if (rc)
125 return rc;
126
127 rc = regmap_update_bits(wled->regmap,
128 wled->addr + PM8941_WLED_REG_SYNC,
129 PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_CLEAR);
130 return rc;
131 }
132
pm8941_wled_setup(struct pm8941_wled * wled)133 static int pm8941_wled_setup(struct pm8941_wled *wled)
134 {
135 int rc;
136 int i;
137
138 rc = regmap_update_bits(wled->regmap,
139 wled->addr + PM8941_WLED_REG_OVP,
140 PM8941_WLED_REG_OVP_MASK, wled->cfg.ovp);
141 if (rc)
142 return rc;
143
144 rc = regmap_update_bits(wled->regmap,
145 wled->addr + PM8941_WLED_REG_BOOST,
146 PM8941_WLED_REG_BOOST_MASK, wled->cfg.i_boost_limit);
147 if (rc)
148 return rc;
149
150 rc = regmap_update_bits(wled->regmap,
151 wled->addr + PM8941_WLED_REG_FREQ,
152 PM8941_WLED_REG_FREQ_MASK, wled->cfg.switch_freq);
153 if (rc)
154 return rc;
155
156 if (wled->cfg.cs_out_en) {
157 u8 all = (BIT(wled->cfg.num_strings) - 1)
158 << PM8941_WLED_REG_SINK_SHFT;
159
160 rc = regmap_update_bits(wled->regmap,
161 wled->addr + PM8941_WLED_REG_SINK,
162 PM8941_WLED_REG_SINK_MASK, all);
163 if (rc)
164 return rc;
165 }
166
167 for (i = 0; i < wled->cfg.num_strings; ++i) {
168 u16 addr = wled->addr + PM8941_WLED_REG_STR_OFFSET * i;
169
170 rc = regmap_update_bits(wled->regmap,
171 addr + PM8941_WLED_REG_STR_MOD_EN_BASE,
172 PM8941_WLED_REG_STR_MOD_MASK,
173 PM8941_WLED_REG_STR_MOD_EN);
174 if (rc)
175 return rc;
176
177 if (wled->cfg.ext_gen) {
178 rc = regmap_update_bits(wled->regmap,
179 addr + PM8941_WLED_REG_STR_MOD_SRC_BASE,
180 PM8941_WLED_REG_STR_MOD_SRC_MASK,
181 PM8941_WLED_REG_STR_MOD_SRC_EXT);
182 if (rc)
183 return rc;
184 }
185
186 rc = regmap_update_bits(wled->regmap,
187 addr + PM8941_WLED_REG_STR_SCALE_BASE,
188 PM8941_WLED_REG_STR_SCALE_MASK,
189 wled->cfg.i_limit);
190 if (rc)
191 return rc;
192
193 rc = regmap_update_bits(wled->regmap,
194 addr + PM8941_WLED_REG_STR_CABC_BASE,
195 PM8941_WLED_REG_STR_CABC_MASK,
196 wled->cfg.cabc_en ?
197 PM8941_WLED_REG_STR_CABC_EN : 0);
198 if (rc)
199 return rc;
200 }
201
202 return 0;
203 }
204
205 static const struct pm8941_wled_config pm8941_wled_config_defaults = {
206 .i_boost_limit = 3,
207 .i_limit = 20,
208 .ovp = 2,
209 .switch_freq = 5,
210 .num_strings = 0,
211 .cs_out_en = false,
212 .ext_gen = false,
213 .cabc_en = false,
214 };
215
216 struct pm8941_wled_var_cfg {
217 const u32 *values;
218 u32 (*fn)(u32);
219 int size;
220 };
221
222 static const u32 pm8941_wled_i_boost_limit_values[] = {
223 105, 385, 525, 805, 980, 1260, 1400, 1680,
224 };
225
226 static const struct pm8941_wled_var_cfg pm8941_wled_i_boost_limit_cfg = {
227 .values = pm8941_wled_i_boost_limit_values,
228 .size = ARRAY_SIZE(pm8941_wled_i_boost_limit_values),
229 };
230
231 static const u32 pm8941_wled_ovp_values[] = {
232 35, 32, 29, 27,
233 };
234
235 static const struct pm8941_wled_var_cfg pm8941_wled_ovp_cfg = {
236 .values = pm8941_wled_ovp_values,
237 .size = ARRAY_SIZE(pm8941_wled_ovp_values),
238 };
239
pm8941_wled_num_strings_values_fn(u32 idx)240 static u32 pm8941_wled_num_strings_values_fn(u32 idx)
241 {
242 return idx + 1;
243 }
244
245 static const struct pm8941_wled_var_cfg pm8941_wled_num_strings_cfg = {
246 .fn = pm8941_wled_num_strings_values_fn,
247 .size = 3,
248 };
249
pm8941_wled_switch_freq_values_fn(u32 idx)250 static u32 pm8941_wled_switch_freq_values_fn(u32 idx)
251 {
252 return 19200 / (2 * (1 + idx));
253 }
254
255 static const struct pm8941_wled_var_cfg pm8941_wled_switch_freq_cfg = {
256 .fn = pm8941_wled_switch_freq_values_fn,
257 .size = 16,
258 };
259
260 static const struct pm8941_wled_var_cfg pm8941_wled_i_limit_cfg = {
261 .size = 26,
262 };
263
pm8941_wled_values(const struct pm8941_wled_var_cfg * cfg,u32 idx)264 static u32 pm8941_wled_values(const struct pm8941_wled_var_cfg *cfg, u32 idx)
265 {
266 if (idx >= cfg->size)
267 return UINT_MAX;
268 if (cfg->fn)
269 return cfg->fn(idx);
270 if (cfg->values)
271 return cfg->values[idx];
272 return idx;
273 }
274
pm8941_wled_configure(struct pm8941_wled * wled,struct device * dev)275 static int pm8941_wled_configure(struct pm8941_wled *wled, struct device *dev)
276 {
277 struct pm8941_wled_config *cfg = &wled->cfg;
278 u32 val;
279 int rc;
280 u32 c;
281 int i;
282 int j;
283
284 const struct {
285 const char *name;
286 u32 *val_ptr;
287 const struct pm8941_wled_var_cfg *cfg;
288 } u32_opts[] = {
289 {
290 "qcom,current-boost-limit",
291 &cfg->i_boost_limit,
292 .cfg = &pm8941_wled_i_boost_limit_cfg,
293 },
294 {
295 "qcom,current-limit",
296 &cfg->i_limit,
297 .cfg = &pm8941_wled_i_limit_cfg,
298 },
299 {
300 "qcom,ovp",
301 &cfg->ovp,
302 .cfg = &pm8941_wled_ovp_cfg,
303 },
304 {
305 "qcom,switching-freq",
306 &cfg->switch_freq,
307 .cfg = &pm8941_wled_switch_freq_cfg,
308 },
309 {
310 "qcom,num-strings",
311 &cfg->num_strings,
312 .cfg = &pm8941_wled_num_strings_cfg,
313 },
314 };
315 const struct {
316 const char *name;
317 bool *val_ptr;
318 } bool_opts[] = {
319 { "qcom,cs-out", &cfg->cs_out_en, },
320 { "qcom,ext-gen", &cfg->ext_gen, },
321 { "qcom,cabc", &cfg->cabc_en, },
322 };
323
324 rc = of_property_read_u32(dev->of_node, "reg", &val);
325 if (rc || val > 0xffff) {
326 dev_err(dev, "invalid IO resources\n");
327 return rc ? rc : -EINVAL;
328 }
329 wled->addr = val;
330
331 rc = of_property_read_string(dev->of_node, "label", &wled->name);
332 if (rc)
333 wled->name = dev->of_node->name;
334
335 *cfg = pm8941_wled_config_defaults;
336 for (i = 0; i < ARRAY_SIZE(u32_opts); ++i) {
337 rc = of_property_read_u32(dev->of_node, u32_opts[i].name, &val);
338 if (rc == -EINVAL) {
339 continue;
340 } else if (rc) {
341 dev_err(dev, "error reading '%s'\n", u32_opts[i].name);
342 return rc;
343 }
344
345 c = UINT_MAX;
346 for (j = 0; c != val; j++) {
347 c = pm8941_wled_values(u32_opts[i].cfg, j);
348 if (c == UINT_MAX) {
349 dev_err(dev, "invalid value for '%s'\n",
350 u32_opts[i].name);
351 return -EINVAL;
352 }
353 }
354
355 dev_dbg(dev, "'%s' = %u\n", u32_opts[i].name, c);
356 *u32_opts[i].val_ptr = j;
357 }
358
359 for (i = 0; i < ARRAY_SIZE(bool_opts); ++i) {
360 if (of_property_read_bool(dev->of_node, bool_opts[i].name))
361 *bool_opts[i].val_ptr = true;
362 }
363
364 cfg->num_strings = cfg->num_strings + 1;
365
366 return 0;
367 }
368
369 static const struct backlight_ops pm8941_wled_ops = {
370 .update_status = pm8941_wled_update_status,
371 };
372
pm8941_wled_probe(struct platform_device * pdev)373 static int pm8941_wled_probe(struct platform_device *pdev)
374 {
375 struct backlight_properties props;
376 struct backlight_device *bl;
377 struct pm8941_wled *wled;
378 struct regmap *regmap;
379 u32 val;
380 int rc;
381
382 regmap = dev_get_regmap(pdev->dev.parent, NULL);
383 if (!regmap) {
384 dev_err(&pdev->dev, "Unable to get regmap\n");
385 return -EINVAL;
386 }
387
388 wled = devm_kzalloc(&pdev->dev, sizeof(*wled), GFP_KERNEL);
389 if (!wled)
390 return -ENOMEM;
391
392 wled->regmap = regmap;
393
394 rc = pm8941_wled_configure(wled, &pdev->dev);
395 if (rc)
396 return rc;
397
398 rc = pm8941_wled_setup(wled);
399 if (rc)
400 return rc;
401
402 val = PM8941_WLED_DEFAULT_BRIGHTNESS;
403 of_property_read_u32(pdev->dev.of_node, "default-brightness", &val);
404
405 memset(&props, 0, sizeof(struct backlight_properties));
406 props.type = BACKLIGHT_RAW;
407 props.brightness = val;
408 props.max_brightness = PM8941_WLED_REG_VAL_MAX;
409 bl = devm_backlight_device_register(&pdev->dev, wled->name,
410 &pdev->dev, wled,
411 &pm8941_wled_ops, &props);
412 return PTR_ERR_OR_ZERO(bl);
413 };
414
415 static const struct of_device_id pm8941_wled_match_table[] = {
416 { .compatible = "qcom,pm8941-wled" },
417 {}
418 };
419 MODULE_DEVICE_TABLE(of, pm8941_wled_match_table);
420
421 static struct platform_driver pm8941_wled_driver = {
422 .probe = pm8941_wled_probe,
423 .driver = {
424 .name = "pm8941-wled",
425 .of_match_table = pm8941_wled_match_table,
426 },
427 };
428
429 module_platform_driver(pm8941_wled_driver);
430
431 MODULE_DESCRIPTION("pm8941 wled driver");
432 MODULE_LICENSE("GPL v2");
433
