1 /*
2 * AS3711 PMIC backlight driver, using DCDC Step Up Converters
3 *
4 * Copyright (C) 2012 Renesas Electronics Corporation
5 * Author: Guennadi Liakhovetski, <g.liakhovetski@gmx.de>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the version 2 of the GNU General Public License as
9 * published by the Free Software Foundation
10 */
11
12 #include <linux/backlight.h>
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/err.h>
16 #include <linux/fb.h>
17 #include <linux/kernel.h>
18 #include <linux/mfd/as3711.h>
19 #include <linux/module.h>
20 #include <linux/platform_device.h>
21 #include <linux/regmap.h>
22 #include <linux/slab.h>
23
24 enum as3711_bl_type {
25 AS3711_BL_SU1,
26 AS3711_BL_SU2,
27 };
28
29 struct as3711_bl_data {
30 bool powered;
31 const char *fb_name;
32 struct device *fb_dev;
33 enum as3711_bl_type type;
34 int brightness;
35 struct backlight_device *bl;
36 };
37
38 struct as3711_bl_supply {
39 struct as3711_bl_data su1;
40 struct as3711_bl_data su2;
41 const struct as3711_bl_pdata *pdata;
42 struct as3711 *as3711;
43 };
44
to_supply(struct as3711_bl_data * su)45 static struct as3711_bl_supply *to_supply(struct as3711_bl_data *su)
46 {
47 switch (su->type) {
48 case AS3711_BL_SU1:
49 return container_of(su, struct as3711_bl_supply, su1);
50 case AS3711_BL_SU2:
51 return container_of(su, struct as3711_bl_supply, su2);
52 }
53 return NULL;
54 }
55
as3711_set_brightness_auto_i(struct as3711_bl_data * data,unsigned int brightness)56 static int as3711_set_brightness_auto_i(struct as3711_bl_data *data,
57 unsigned int brightness)
58 {
59 struct as3711_bl_supply *supply = to_supply(data);
60 struct as3711 *as3711 = supply->as3711;
61 const struct as3711_bl_pdata *pdata = supply->pdata;
62 int ret = 0;
63
64 /* Only all equal current values are supported */
65 if (pdata->su2_auto_curr1)
66 ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
67 brightness);
68 if (!ret && pdata->su2_auto_curr2)
69 ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
70 brightness);
71 if (!ret && pdata->su2_auto_curr3)
72 ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
73 brightness);
74
75 return ret;
76 }
77
as3711_set_brightness_v(struct as3711 * as3711,unsigned int brightness,unsigned int reg)78 static int as3711_set_brightness_v(struct as3711 *as3711,
79 unsigned int brightness,
80 unsigned int reg)
81 {
82 if (brightness > 31)
83 return -EINVAL;
84
85 return regmap_update_bits(as3711->regmap, reg, 0xf0,
86 brightness << 4);
87 }
88
as3711_bl_su2_reset(struct as3711_bl_supply * supply)89 static int as3711_bl_su2_reset(struct as3711_bl_supply *supply)
90 {
91 struct as3711 *as3711 = supply->as3711;
92 int ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_5,
93 3, supply->pdata->su2_fbprot);
94 if (!ret)
95 ret = regmap_update_bits(as3711->regmap,
96 AS3711_STEPUP_CONTROL_2, 1, 0);
97 if (!ret)
98 ret = regmap_update_bits(as3711->regmap,
99 AS3711_STEPUP_CONTROL_2, 1, 1);
100 return ret;
101 }
102
103 /*
104 * Someone with less fragile or less expensive hardware could try to simplify
105 * the brightness adjustment procedure.
106 */
as3711_bl_update_status(struct backlight_device * bl)107 static int as3711_bl_update_status(struct backlight_device *bl)
108 {
109 struct as3711_bl_data *data = bl_get_data(bl);
110 struct as3711_bl_supply *supply = to_supply(data);
111 struct as3711 *as3711 = supply->as3711;
112 int brightness = bl->props.brightness;
113 int ret = 0;
114
115 dev_dbg(&bl->dev, "%s(): brightness %u, pwr %x, blank %x, state %x\n",
116 __func__, bl->props.brightness, bl->props.power,
117 bl->props.fb_blank, bl->props.state);
118
119 if (bl->props.power != FB_BLANK_UNBLANK ||
120 bl->props.fb_blank != FB_BLANK_UNBLANK ||
121 bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
122 brightness = 0;
123
124 if (data->type == AS3711_BL_SU1) {
125 ret = as3711_set_brightness_v(as3711, brightness,
126 AS3711_STEPUP_CONTROL_1);
127 } else {
128 const struct as3711_bl_pdata *pdata = supply->pdata;
129
130 switch (pdata->su2_feedback) {
131 case AS3711_SU2_VOLTAGE:
132 ret = as3711_set_brightness_v(as3711, brightness,
133 AS3711_STEPUP_CONTROL_2);
134 break;
135 case AS3711_SU2_CURR_AUTO:
136 ret = as3711_set_brightness_auto_i(data, brightness / 4);
137 if (ret < 0)
138 return ret;
139 if (brightness) {
140 ret = as3711_bl_su2_reset(supply);
141 if (ret < 0)
142 return ret;
143 udelay(500);
144 ret = as3711_set_brightness_auto_i(data, brightness);
145 } else {
146 ret = regmap_update_bits(as3711->regmap,
147 AS3711_STEPUP_CONTROL_2, 1, 0);
148 }
149 break;
150 /* Manual one current feedback pin below */
151 case AS3711_SU2_CURR1:
152 ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
153 brightness);
154 break;
155 case AS3711_SU2_CURR2:
156 ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
157 brightness);
158 break;
159 case AS3711_SU2_CURR3:
160 ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
161 brightness);
162 break;
163 default:
164 ret = -EINVAL;
165 }
166 }
167 if (!ret)
168 data->brightness = brightness;
169
170 return ret;
171 }
172
as3711_bl_get_brightness(struct backlight_device * bl)173 static int as3711_bl_get_brightness(struct backlight_device *bl)
174 {
175 struct as3711_bl_data *data = bl_get_data(bl);
176
177 return data->brightness;
178 }
179
180 static const struct backlight_ops as3711_bl_ops = {
181 .update_status = as3711_bl_update_status,
182 .get_brightness = as3711_bl_get_brightness,
183 };
184
as3711_bl_init_su2(struct as3711_bl_supply * supply)185 static int as3711_bl_init_su2(struct as3711_bl_supply *supply)
186 {
187 struct as3711 *as3711 = supply->as3711;
188 const struct as3711_bl_pdata *pdata = supply->pdata;
189 u8 ctl = 0;
190 int ret;
191
192 dev_dbg(as3711->dev, "%s(): use %u\n", __func__, pdata->su2_feedback);
193
194 /* Turn SU2 off */
195 ret = regmap_write(as3711->regmap, AS3711_STEPUP_CONTROL_2, 0);
196 if (ret < 0)
197 return ret;
198
199 switch (pdata->su2_feedback) {
200 case AS3711_SU2_VOLTAGE:
201 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 0);
202 break;
203 case AS3711_SU2_CURR1:
204 ctl = 1;
205 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 1);
206 break;
207 case AS3711_SU2_CURR2:
208 ctl = 4;
209 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 2);
210 break;
211 case AS3711_SU2_CURR3:
212 ctl = 0x10;
213 ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 3);
214 break;
215 case AS3711_SU2_CURR_AUTO:
216 if (pdata->su2_auto_curr1)
217 ctl = 2;
218 if (pdata->su2_auto_curr2)
219 ctl |= 8;
220 if (pdata->su2_auto_curr3)
221 ctl |= 0x20;
222 ret = 0;
223 break;
224 default:
225 return -EINVAL;
226 }
227
228 if (!ret)
229 ret = regmap_write(as3711->regmap, AS3711_CURR_CONTROL, ctl);
230
231 return ret;
232 }
233
as3711_bl_register(struct platform_device * pdev,unsigned int max_brightness,struct as3711_bl_data * su)234 static int as3711_bl_register(struct platform_device *pdev,
235 unsigned int max_brightness, struct as3711_bl_data *su)
236 {
237 struct backlight_properties props = {.type = BACKLIGHT_RAW,};
238 struct backlight_device *bl;
239
240 /* max tuning I = 31uA for voltage- and 38250uA for current-feedback */
241 props.max_brightness = max_brightness;
242
243 bl = devm_backlight_device_register(&pdev->dev,
244 su->type == AS3711_BL_SU1 ?
245 "as3711-su1" : "as3711-su2",
246 &pdev->dev, su,
247 &as3711_bl_ops, &props);
248 if (IS_ERR(bl)) {
249 dev_err(&pdev->dev, "failed to register backlight\n");
250 return PTR_ERR(bl);
251 }
252
253 bl->props.brightness = props.max_brightness;
254
255 backlight_update_status(bl);
256
257 su->bl = bl;
258
259 return 0;
260 }
261
as3711_backlight_parse_dt(struct device * dev)262 static int as3711_backlight_parse_dt(struct device *dev)
263 {
264 struct as3711_bl_pdata *pdata = dev_get_platdata(dev);
265 struct device_node *bl, *fb;
266 int ret;
267
268 bl = of_get_child_by_name(dev->parent->of_node, "backlight");
269 if (!bl) {
270 dev_dbg(dev, "backlight node not found\n");
271 return -ENODEV;
272 }
273
274 fb = of_parse_phandle(bl, "su1-dev", 0);
275 if (fb) {
276 pdata->su1_fb = fb->full_name;
277
278 ret = of_property_read_u32(bl, "su1-max-uA", &pdata->su1_max_uA);
279 if (pdata->su1_max_uA <= 0)
280 ret = -EINVAL;
281 if (ret < 0)
282 goto err_put_bl;
283 }
284
285 fb = of_parse_phandle(bl, "su2-dev", 0);
286 if (fb) {
287 int count = 0;
288
289 pdata->su2_fb = fb->full_name;
290
291 ret = of_property_read_u32(bl, "su2-max-uA", &pdata->su2_max_uA);
292 if (pdata->su2_max_uA <= 0)
293 ret = -EINVAL;
294 if (ret < 0)
295 goto err_put_bl;
296
297 if (of_find_property(bl, "su2-feedback-voltage", NULL)) {
298 pdata->su2_feedback = AS3711_SU2_VOLTAGE;
299 count++;
300 }
301 if (of_find_property(bl, "su2-feedback-curr1", NULL)) {
302 pdata->su2_feedback = AS3711_SU2_CURR1;
303 count++;
304 }
305 if (of_find_property(bl, "su2-feedback-curr2", NULL)) {
306 pdata->su2_feedback = AS3711_SU2_CURR2;
307 count++;
308 }
309 if (of_find_property(bl, "su2-feedback-curr3", NULL)) {
310 pdata->su2_feedback = AS3711_SU2_CURR3;
311 count++;
312 }
313 if (of_find_property(bl, "su2-feedback-curr-auto", NULL)) {
314 pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
315 count++;
316 }
317 if (count != 1) {
318 ret = -EINVAL;
319 goto err_put_bl;
320 }
321
322 count = 0;
323 if (of_find_property(bl, "su2-fbprot-lx-sd4", NULL)) {
324 pdata->su2_fbprot = AS3711_SU2_LX_SD4;
325 count++;
326 }
327 if (of_find_property(bl, "su2-fbprot-gpio2", NULL)) {
328 pdata->su2_fbprot = AS3711_SU2_GPIO2;
329 count++;
330 }
331 if (of_find_property(bl, "su2-fbprot-gpio3", NULL)) {
332 pdata->su2_fbprot = AS3711_SU2_GPIO3;
333 count++;
334 }
335 if (of_find_property(bl, "su2-fbprot-gpio4", NULL)) {
336 pdata->su2_fbprot = AS3711_SU2_GPIO4;
337 count++;
338 }
339 if (count != 1) {
340 ret = -EINVAL;
341 goto err_put_bl;
342 }
343
344 count = 0;
345 if (of_find_property(bl, "su2-auto-curr1", NULL)) {
346 pdata->su2_auto_curr1 = true;
347 count++;
348 }
349 if (of_find_property(bl, "su2-auto-curr2", NULL)) {
350 pdata->su2_auto_curr2 = true;
351 count++;
352 }
353 if (of_find_property(bl, "su2-auto-curr3", NULL)) {
354 pdata->su2_auto_curr3 = true;
355 count++;
356 }
357
358 /*
359 * At least one su2-auto-curr* must be specified iff
360 * AS3711_SU2_CURR_AUTO is used
361 */
362 if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO)) {
363 ret = -EINVAL;
364 goto err_put_bl;
365 }
366 }
367
368 of_node_put(bl);
369
370 return 0;
371
372 err_put_bl:
373 of_node_put(bl);
374
375 return ret;
376 }
377
as3711_backlight_probe(struct platform_device * pdev)378 static int as3711_backlight_probe(struct platform_device *pdev)
379 {
380 struct as3711_bl_pdata *pdata = dev_get_platdata(&pdev->dev);
381 struct as3711 *as3711 = dev_get_drvdata(pdev->dev.parent);
382 struct as3711_bl_supply *supply;
383 struct as3711_bl_data *su;
384 unsigned int max_brightness;
385 int ret;
386
387 if (!pdata) {
388 dev_err(&pdev->dev, "No platform data, exiting...\n");
389 return -ENODEV;
390 }
391
392 if (pdev->dev.parent->of_node) {
393 ret = as3711_backlight_parse_dt(&pdev->dev);
394 if (ret < 0) {
395 dev_err(&pdev->dev, "DT parsing failed: %d\n", ret);
396 return ret;
397 }
398 }
399
400 if (!pdata->su1_fb && !pdata->su2_fb) {
401 dev_err(&pdev->dev, "No framebuffer specified\n");
402 return -EINVAL;
403 }
404
405 /*
406 * Due to possible hardware damage I chose to block all modes,
407 * unsupported on my hardware. Anyone, wishing to use any of those modes
408 * will have to first review the code, then activate and test it.
409 */
410 if (pdata->su1_fb ||
411 pdata->su2_fbprot != AS3711_SU2_GPIO4 ||
412 pdata->su2_feedback != AS3711_SU2_CURR_AUTO) {
413 dev_warn(&pdev->dev,
414 "Attention! An untested mode has been chosen!\n"
415 "Please, review the code, enable, test, and report success:-)\n");
416 return -EINVAL;
417 }
418
419 supply = devm_kzalloc(&pdev->dev, sizeof(*supply), GFP_KERNEL);
420 if (!supply)
421 return -ENOMEM;
422
423 supply->as3711 = as3711;
424 supply->pdata = pdata;
425
426 if (pdata->su1_fb) {
427 su = &supply->su1;
428 su->fb_name = pdata->su1_fb;
429 su->type = AS3711_BL_SU1;
430
431 max_brightness = min(pdata->su1_max_uA, 31);
432 ret = as3711_bl_register(pdev, max_brightness, su);
433 if (ret < 0)
434 return ret;
435 }
436
437 if (pdata->su2_fb) {
438 su = &supply->su2;
439 su->fb_name = pdata->su2_fb;
440 su->type = AS3711_BL_SU2;
441
442 switch (pdata->su2_fbprot) {
443 case AS3711_SU2_GPIO2:
444 case AS3711_SU2_GPIO3:
445 case AS3711_SU2_GPIO4:
446 case AS3711_SU2_LX_SD4:
447 break;
448 default:
449 return -EINVAL;
450 }
451
452 switch (pdata->su2_feedback) {
453 case AS3711_SU2_VOLTAGE:
454 max_brightness = min(pdata->su2_max_uA, 31);
455 break;
456 case AS3711_SU2_CURR1:
457 case AS3711_SU2_CURR2:
458 case AS3711_SU2_CURR3:
459 case AS3711_SU2_CURR_AUTO:
460 max_brightness = min(pdata->su2_max_uA / 150, 255);
461 break;
462 default:
463 return -EINVAL;
464 }
465
466 ret = as3711_bl_init_su2(supply);
467 if (ret < 0)
468 return ret;
469
470 ret = as3711_bl_register(pdev, max_brightness, su);
471 if (ret < 0)
472 return ret;
473 }
474
475 platform_set_drvdata(pdev, supply);
476
477 return 0;
478 }
479
480 static struct platform_driver as3711_backlight_driver = {
481 .driver = {
482 .name = "as3711-backlight",
483 },
484 .probe = as3711_backlight_probe,
485 };
486
487 module_platform_driver(as3711_backlight_driver);
488
489 MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs");
490 MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de");
491 MODULE_LICENSE("GPL");
492 MODULE_ALIAS("platform:as3711-backlight");
493