1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2015, Sony Mobile Communications, AB.
3 */
4
5 #include <linux/kernel.h>
6 #include <linux/backlight.h>
7 #include <linux/module.h>
8 #include <linux/of.h>
9 #include <linux/of_device.h>
10 #include <linux/regmap.h>
11
12 /* From DT binding */
13 #define PM8941_WLED_DEFAULT_BRIGHTNESS 2048
14
15 #define PM8941_WLED_REG_VAL_BASE 0x40
16 #define PM8941_WLED_REG_VAL_MAX 0xFFF
17
18 #define PM8941_WLED_REG_MOD_EN 0x46
19 #define PM8941_WLED_REG_MOD_EN_BIT BIT(7)
20 #define PM8941_WLED_REG_MOD_EN_MASK BIT(7)
21
22 #define PM8941_WLED_REG_SYNC 0x47
23 #define PM8941_WLED_REG_SYNC_MASK 0x07
24 #define PM8941_WLED_REG_SYNC_LED1 BIT(0)
25 #define PM8941_WLED_REG_SYNC_LED2 BIT(1)
26 #define PM8941_WLED_REG_SYNC_LED3 BIT(2)
27 #define PM8941_WLED_REG_SYNC_ALL 0x07
28 #define PM8941_WLED_REG_SYNC_CLEAR 0x00
29
30 #define PM8941_WLED_REG_FREQ 0x4c
31 #define PM8941_WLED_REG_FREQ_MASK 0x0f
32
33 #define PM8941_WLED_REG_OVP 0x4d
34 #define PM8941_WLED_REG_OVP_MASK 0x03
35
36 #define PM8941_WLED_REG_BOOST 0x4e
37 #define PM8941_WLED_REG_BOOST_MASK 0x07
38
39 #define PM8941_WLED_REG_SINK 0x4f
40 #define PM8941_WLED_REG_SINK_MASK 0xe0
41 #define PM8941_WLED_REG_SINK_SHFT 0x05
42
43 /* Per-'string' registers below */
44 #define PM8941_WLED_REG_STR_OFFSET 0x10
45
46 #define PM8941_WLED_REG_STR_MOD_EN_BASE 0x60
47 #define PM8941_WLED_REG_STR_MOD_MASK BIT(7)
48 #define PM8941_WLED_REG_STR_MOD_EN BIT(7)
49
50 #define PM8941_WLED_REG_STR_SCALE_BASE 0x62
51 #define PM8941_WLED_REG_STR_SCALE_MASK 0x1f
52
53 #define PM8941_WLED_REG_STR_MOD_SRC_BASE 0x63
54 #define PM8941_WLED_REG_STR_MOD_SRC_MASK 0x01
55 #define PM8941_WLED_REG_STR_MOD_SRC_INT 0x00
56 #define PM8941_WLED_REG_STR_MOD_SRC_EXT 0x01
57
58 #define PM8941_WLED_REG_STR_CABC_BASE 0x66
59 #define PM8941_WLED_REG_STR_CABC_MASK BIT(7)
60 #define PM8941_WLED_REG_STR_CABC_EN BIT(7)
61
62 struct pm8941_wled_config {
63 u32 i_boost_limit;
64 u32 ovp;
65 u32 switch_freq;
66 u32 num_strings;
67 u32 i_limit;
68 bool cs_out_en;
69 bool ext_gen;
70 bool cabc_en;
71 };
72
73 struct pm8941_wled {
74 const char *name;
75 struct regmap *regmap;
76 u16 addr;
77
78 struct pm8941_wled_config cfg;
79 };
80
pm8941_wled_update_status(struct backlight_device * bl)81 static int pm8941_wled_update_status(struct backlight_device *bl)
82 {
83 struct pm8941_wled *wled = bl_get_data(bl);
84 u16 val = bl->props.brightness;
85 u8 ctrl = 0;
86 int rc;
87 int i;
88
89 if (bl->props.power != FB_BLANK_UNBLANK ||
90 bl->props.fb_blank != FB_BLANK_UNBLANK ||
91 bl->props.state & BL_CORE_FBBLANK)
92 val = 0;
93
94 if (val != 0)
95 ctrl = PM8941_WLED_REG_MOD_EN_BIT;
96
97 rc = regmap_update_bits(wled->regmap,
98 wled->addr + PM8941_WLED_REG_MOD_EN,
99 PM8941_WLED_REG_MOD_EN_MASK, ctrl);
100 if (rc)
101 return rc;
102
103 for (i = 0; i < wled->cfg.num_strings; ++i) {
104 u8 v[2] = { val & 0xff, (val >> 8) & 0xf };
105
106 rc = regmap_bulk_write(wled->regmap,
107 wled->addr + PM8941_WLED_REG_VAL_BASE + 2 * i,
108 v, 2);
109 if (rc)
110 return rc;
111 }
112
113 rc = regmap_update_bits(wled->regmap,
114 wled->addr + PM8941_WLED_REG_SYNC,
115 PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_ALL);
116 if (rc)
117 return rc;
118
119 rc = regmap_update_bits(wled->regmap,
120 wled->addr + PM8941_WLED_REG_SYNC,
121 PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_CLEAR);
122 return rc;
123 }
124
pm8941_wled_setup(struct pm8941_wled * wled)125 static int pm8941_wled_setup(struct pm8941_wled *wled)
126 {
127 int rc;
128 int i;
129
130 rc = regmap_update_bits(wled->regmap,
131 wled->addr + PM8941_WLED_REG_OVP,
132 PM8941_WLED_REG_OVP_MASK, wled->cfg.ovp);
133 if (rc)
134 return rc;
135
136 rc = regmap_update_bits(wled->regmap,
137 wled->addr + PM8941_WLED_REG_BOOST,
138 PM8941_WLED_REG_BOOST_MASK, wled->cfg.i_boost_limit);
139 if (rc)
140 return rc;
141
142 rc = regmap_update_bits(wled->regmap,
143 wled->addr + PM8941_WLED_REG_FREQ,
144 PM8941_WLED_REG_FREQ_MASK, wled->cfg.switch_freq);
145 if (rc)
146 return rc;
147
148 if (wled->cfg.cs_out_en) {
149 u8 all = (BIT(wled->cfg.num_strings) - 1)
150 << PM8941_WLED_REG_SINK_SHFT;
151
152 rc = regmap_update_bits(wled->regmap,
153 wled->addr + PM8941_WLED_REG_SINK,
154 PM8941_WLED_REG_SINK_MASK, all);
155 if (rc)
156 return rc;
157 }
158
159 for (i = 0; i < wled->cfg.num_strings; ++i) {
160 u16 addr = wled->addr + PM8941_WLED_REG_STR_OFFSET * i;
161
162 rc = regmap_update_bits(wled->regmap,
163 addr + PM8941_WLED_REG_STR_MOD_EN_BASE,
164 PM8941_WLED_REG_STR_MOD_MASK,
165 PM8941_WLED_REG_STR_MOD_EN);
166 if (rc)
167 return rc;
168
169 if (wled->cfg.ext_gen) {
170 rc = regmap_update_bits(wled->regmap,
171 addr + PM8941_WLED_REG_STR_MOD_SRC_BASE,
172 PM8941_WLED_REG_STR_MOD_SRC_MASK,
173 PM8941_WLED_REG_STR_MOD_SRC_EXT);
174 if (rc)
175 return rc;
176 }
177
178 rc = regmap_update_bits(wled->regmap,
179 addr + PM8941_WLED_REG_STR_SCALE_BASE,
180 PM8941_WLED_REG_STR_SCALE_MASK,
181 wled->cfg.i_limit);
182 if (rc)
183 return rc;
184
185 rc = regmap_update_bits(wled->regmap,
186 addr + PM8941_WLED_REG_STR_CABC_BASE,
187 PM8941_WLED_REG_STR_CABC_MASK,
188 wled->cfg.cabc_en ?
189 PM8941_WLED_REG_STR_CABC_EN : 0);
190 if (rc)
191 return rc;
192 }
193
194 return 0;
195 }
196
197 static const struct pm8941_wled_config pm8941_wled_config_defaults = {
198 .i_boost_limit = 3,
199 .i_limit = 20,
200 .ovp = 2,
201 .switch_freq = 5,
202 .num_strings = 0,
203 .cs_out_en = false,
204 .ext_gen = false,
205 .cabc_en = false,
206 };
207
208 struct pm8941_wled_var_cfg {
209 const u32 *values;
210 u32 (*fn)(u32);
211 int size;
212 };
213
214 static const u32 pm8941_wled_i_boost_limit_values[] = {
215 105, 385, 525, 805, 980, 1260, 1400, 1680,
216 };
217
218 static const struct pm8941_wled_var_cfg pm8941_wled_i_boost_limit_cfg = {
219 .values = pm8941_wled_i_boost_limit_values,
220 .size = ARRAY_SIZE(pm8941_wled_i_boost_limit_values),
221 };
222
223 static const u32 pm8941_wled_ovp_values[] = {
224 35, 32, 29, 27,
225 };
226
227 static const struct pm8941_wled_var_cfg pm8941_wled_ovp_cfg = {
228 .values = pm8941_wled_ovp_values,
229 .size = ARRAY_SIZE(pm8941_wled_ovp_values),
230 };
231
pm8941_wled_num_strings_values_fn(u32 idx)232 static u32 pm8941_wled_num_strings_values_fn(u32 idx)
233 {
234 return idx + 1;
235 }
236
237 static const struct pm8941_wled_var_cfg pm8941_wled_num_strings_cfg = {
238 .fn = pm8941_wled_num_strings_values_fn,
239 .size = 3,
240 };
241
pm8941_wled_switch_freq_values_fn(u32 idx)242 static u32 pm8941_wled_switch_freq_values_fn(u32 idx)
243 {
244 return 19200 / (2 * (1 + idx));
245 }
246
247 static const struct pm8941_wled_var_cfg pm8941_wled_switch_freq_cfg = {
248 .fn = pm8941_wled_switch_freq_values_fn,
249 .size = 16,
250 };
251
252 static const struct pm8941_wled_var_cfg pm8941_wled_i_limit_cfg = {
253 .size = 26,
254 };
255
pm8941_wled_values(const struct pm8941_wled_var_cfg * cfg,u32 idx)256 static u32 pm8941_wled_values(const struct pm8941_wled_var_cfg *cfg, u32 idx)
257 {
258 if (idx >= cfg->size)
259 return UINT_MAX;
260 if (cfg->fn)
261 return cfg->fn(idx);
262 if (cfg->values)
263 return cfg->values[idx];
264 return idx;
265 }
266
pm8941_wled_configure(struct pm8941_wled * wled,struct device * dev)267 static int pm8941_wled_configure(struct pm8941_wled *wled, struct device *dev)
268 {
269 struct pm8941_wled_config *cfg = &wled->cfg;
270 u32 val;
271 int rc;
272 u32 c;
273 int i;
274 int j;
275
276 const struct {
277 const char *name;
278 u32 *val_ptr;
279 const struct pm8941_wled_var_cfg *cfg;
280 } u32_opts[] = {
281 {
282 "qcom,current-boost-limit",
283 &cfg->i_boost_limit,
284 .cfg = &pm8941_wled_i_boost_limit_cfg,
285 },
286 {
287 "qcom,current-limit",
288 &cfg->i_limit,
289 .cfg = &pm8941_wled_i_limit_cfg,
290 },
291 {
292 "qcom,ovp",
293 &cfg->ovp,
294 .cfg = &pm8941_wled_ovp_cfg,
295 },
296 {
297 "qcom,switching-freq",
298 &cfg->switch_freq,
299 .cfg = &pm8941_wled_switch_freq_cfg,
300 },
301 {
302 "qcom,num-strings",
303 &cfg->num_strings,
304 .cfg = &pm8941_wled_num_strings_cfg,
305 },
306 };
307 const struct {
308 const char *name;
309 bool *val_ptr;
310 } bool_opts[] = {
311 { "qcom,cs-out", &cfg->cs_out_en, },
312 { "qcom,ext-gen", &cfg->ext_gen, },
313 { "qcom,cabc", &cfg->cabc_en, },
314 };
315
316 rc = of_property_read_u32(dev->of_node, "reg", &val);
317 if (rc || val > 0xffff) {
318 dev_err(dev, "invalid IO resources\n");
319 return rc ? rc : -EINVAL;
320 }
321 wled->addr = val;
322
323 rc = of_property_read_string(dev->of_node, "label", &wled->name);
324 if (rc)
325 wled->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", dev->of_node);
326
327 *cfg = pm8941_wled_config_defaults;
328 for (i = 0; i < ARRAY_SIZE(u32_opts); ++i) {
329 rc = of_property_read_u32(dev->of_node, u32_opts[i].name, &val);
330 if (rc == -EINVAL) {
331 continue;
332 } else if (rc) {
333 dev_err(dev, "error reading '%s'\n", u32_opts[i].name);
334 return rc;
335 }
336
337 c = UINT_MAX;
338 for (j = 0; c != val; j++) {
339 c = pm8941_wled_values(u32_opts[i].cfg, j);
340 if (c == UINT_MAX) {
341 dev_err(dev, "invalid value for '%s'\n",
342 u32_opts[i].name);
343 return -EINVAL;
344 }
345 }
346
347 dev_dbg(dev, "'%s' = %u\n", u32_opts[i].name, c);
348 *u32_opts[i].val_ptr = j;
349 }
350
351 for (i = 0; i < ARRAY_SIZE(bool_opts); ++i) {
352 if (of_property_read_bool(dev->of_node, bool_opts[i].name))
353 *bool_opts[i].val_ptr = true;
354 }
355
356 cfg->num_strings = cfg->num_strings + 1;
357
358 return 0;
359 }
360
361 static const struct backlight_ops pm8941_wled_ops = {
362 .update_status = pm8941_wled_update_status,
363 };
364
pm8941_wled_probe(struct platform_device * pdev)365 static int pm8941_wled_probe(struct platform_device *pdev)
366 {
367 struct backlight_properties props;
368 struct backlight_device *bl;
369 struct pm8941_wled *wled;
370 struct regmap *regmap;
371 u32 val;
372 int rc;
373
374 regmap = dev_get_regmap(pdev->dev.parent, NULL);
375 if (!regmap) {
376 dev_err(&pdev->dev, "Unable to get regmap\n");
377 return -EINVAL;
378 }
379
380 wled = devm_kzalloc(&pdev->dev, sizeof(*wled), GFP_KERNEL);
381 if (!wled)
382 return -ENOMEM;
383
384 wled->regmap = regmap;
385
386 rc = pm8941_wled_configure(wled, &pdev->dev);
387 if (rc)
388 return rc;
389
390 rc = pm8941_wled_setup(wled);
391 if (rc)
392 return rc;
393
394 val = PM8941_WLED_DEFAULT_BRIGHTNESS;
395 of_property_read_u32(pdev->dev.of_node, "default-brightness", &val);
396
397 memset(&props, 0, sizeof(struct backlight_properties));
398 props.type = BACKLIGHT_RAW;
399 props.brightness = val;
400 props.max_brightness = PM8941_WLED_REG_VAL_MAX;
401 bl = devm_backlight_device_register(&pdev->dev, wled->name,
402 &pdev->dev, wled,
403 &pm8941_wled_ops, &props);
404 return PTR_ERR_OR_ZERO(bl);
405 };
406
407 static const struct of_device_id pm8941_wled_match_table[] = {
408 { .compatible = "qcom,pm8941-wled" },
409 {}
410 };
411 MODULE_DEVICE_TABLE(of, pm8941_wled_match_table);
412
413 static struct platform_driver pm8941_wled_driver = {
414 .probe = pm8941_wled_probe,
415 .driver = {
416 .name = "pm8941-wled",
417 .of_match_table = pm8941_wled_match_table,
418 },
419 };
420
421 module_platform_driver(pm8941_wled_driver);
422
423 MODULE_DESCRIPTION("pm8941 wled driver");
424 MODULE_LICENSE("GPL v2");
425
