summaryrefslogtreecommitdiff
path: root/drivers/video/backlight/as3711_bl.c
blob: 734a9158946b1f805a3738d9e9c31f25cf8b3314 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
/*
 * AS3711 PMIC backlight driver, using DCDC Step Up Converters
 *
 * Copyright (C) 2012 Renesas Electronics Corporation
 * Author: Guennadi Liakhovetski, <g.liakhovetski@gmx.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the version 2 of the GNU General Public License as
 * published by the Free Software Foundation
 */

#include <linux/backlight.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/fb.h>
#include <linux/kernel.h>
#include <linux/mfd/as3711.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>

enum as3711_bl_type {
	AS3711_BL_SU1,
	AS3711_BL_SU2,
};

struct as3711_bl_data {
	bool powered;
	const char *fb_name;
	struct device *fb_dev;
	enum as3711_bl_type type;
	int brightness;
	struct backlight_device *bl;
};

struct as3711_bl_supply {
	struct as3711_bl_data su1;
	struct as3711_bl_data su2;
	const struct as3711_bl_pdata *pdata;
	struct as3711 *as3711;
};

static struct as3711_bl_supply *to_supply(struct as3711_bl_data *su)
{
	switch (su->type) {
	case AS3711_BL_SU1:
		return container_of(su, struct as3711_bl_supply, su1);
	case AS3711_BL_SU2:
		return container_of(su, struct as3711_bl_supply, su2);
	}
	return NULL;
}

static int as3711_set_brightness_auto_i(struct as3711_bl_data *data,
					unsigned int brightness)
{
	struct as3711_bl_supply *supply = to_supply(data);
	struct as3711 *as3711 = supply->as3711;
	const struct as3711_bl_pdata *pdata = supply->pdata;
	int ret = 0;

	/* Only all equal current values are supported */
	if (pdata->su2_auto_curr1)
		ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
				   brightness);
	if (!ret && pdata->su2_auto_curr2)
		ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
				   brightness);
	if (!ret && pdata->su2_auto_curr3)
		ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
				   brightness);

	return ret;
}

static int as3711_set_brightness_v(struct as3711 *as3711,
				   unsigned int brightness,
				   unsigned int reg)
{
	if (brightness > 31)
		return -EINVAL;

	return regmap_update_bits(as3711->regmap, reg, 0xf0,
				  brightness << 4);
}

static int as3711_bl_su2_reset(struct as3711_bl_supply *supply)
{
	struct as3711 *as3711 = supply->as3711;
	int ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_5,
				     3, supply->pdata->su2_fbprot);
	if (!ret)
		ret = regmap_update_bits(as3711->regmap,
					 AS3711_STEPUP_CONTROL_2, 1, 0);
	if (!ret)
		ret = regmap_update_bits(as3711->regmap,
					 AS3711_STEPUP_CONTROL_2, 1, 1);
	return ret;
}

/*
 * Someone with less fragile or less expensive hardware could try to simplify
 * the brightness adjustment procedure.
 */
static int as3711_bl_update_status(struct backlight_device *bl)
{
	struct as3711_bl_data *data = bl_get_data(bl);
	struct as3711_bl_supply *supply = to_supply(data);
	struct as3711 *as3711 = supply->as3711;
	int brightness = bl->props.brightness;
	int ret = 0;

	dev_dbg(&bl->dev, "%s(): brightness %u, pwr %x, blank %x, state %x\n",
		__func__, bl->props.brightness, bl->props.power,
		bl->props.fb_blank, bl->props.state);

	if (bl->props.power != FB_BLANK_UNBLANK ||
	    bl->props.fb_blank != FB_BLANK_UNBLANK ||
	    bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
		brightness = 0;

	if (data->type == AS3711_BL_SU1) {
		ret = as3711_set_brightness_v(as3711, brightness,
					      AS3711_STEPUP_CONTROL_1);
	} else {
		const struct as3711_bl_pdata *pdata = supply->pdata;

		switch (pdata->su2_feedback) {
		case AS3711_SU2_VOLTAGE:
			ret = as3711_set_brightness_v(as3711, brightness,
						      AS3711_STEPUP_CONTROL_2);
			break;
		case AS3711_SU2_CURR_AUTO:
			ret = as3711_set_brightness_auto_i(data, brightness / 4);
			if (ret < 0)
				return ret;
			if (brightness) {
				ret = as3711_bl_su2_reset(supply);
				if (ret < 0)
					return ret;
				udelay(500);
				ret = as3711_set_brightness_auto_i(data, brightness);
			} else {
				ret = regmap_update_bits(as3711->regmap,
						AS3711_STEPUP_CONTROL_2, 1, 0);
			}
			break;
		/* Manual one current feedback pin below */
		case AS3711_SU2_CURR1:
			ret = regmap_write(as3711->regmap, AS3711_CURR1_VALUE,
					   brightness);
			break;
		case AS3711_SU2_CURR2:
			ret = regmap_write(as3711->regmap, AS3711_CURR2_VALUE,
					   brightness);
			break;
		case AS3711_SU2_CURR3:
			ret = regmap_write(as3711->regmap, AS3711_CURR3_VALUE,
					   brightness);
			break;
		default:
			ret = -EINVAL;
		}
	}
	if (!ret)
		data->brightness = brightness;

	return ret;
}

static int as3711_bl_get_brightness(struct backlight_device *bl)
{
	struct as3711_bl_data *data = bl_get_data(bl);

	return data->brightness;
}

static const struct backlight_ops as3711_bl_ops = {
	.update_status	= as3711_bl_update_status,
	.get_brightness	= as3711_bl_get_brightness,
};

static int as3711_bl_init_su2(struct as3711_bl_supply *supply)
{
	struct as3711 *as3711 = supply->as3711;
	const struct as3711_bl_pdata *pdata = supply->pdata;
	u8 ctl = 0;
	int ret;

	dev_dbg(as3711->dev, "%s(): use %u\n", __func__, pdata->su2_feedback);

	/* Turn SU2 off */
	ret = regmap_write(as3711->regmap, AS3711_STEPUP_CONTROL_2, 0);
	if (ret < 0)
		return ret;

	switch (pdata->su2_feedback) {
	case AS3711_SU2_VOLTAGE:
		ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 0);
		break;
	case AS3711_SU2_CURR1:
		ctl = 1;
		ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 1);
		break;
	case AS3711_SU2_CURR2:
		ctl = 4;
		ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 2);
		break;
	case AS3711_SU2_CURR3:
		ctl = 0x10;
		ret = regmap_update_bits(as3711->regmap, AS3711_STEPUP_CONTROL_4, 3, 3);
		break;
	case AS3711_SU2_CURR_AUTO:
		if (pdata->su2_auto_curr1)
			ctl = 2;
		if (pdata->su2_auto_curr2)
			ctl |= 8;
		if (pdata->su2_auto_curr3)
			ctl |= 0x20;
		ret = 0;
		break;
	default:
		return -EINVAL;
	}

	if (!ret)
		ret = regmap_write(as3711->regmap, AS3711_CURR_CONTROL, ctl);

	return ret;
}

static int as3711_bl_register(struct platform_device *pdev,
			      unsigned int max_brightness, struct as3711_bl_data *su)
{
	struct backlight_properties props = {.type = BACKLIGHT_RAW,};
	struct backlight_device *bl;

	/* max tuning I = 31uA for voltage- and 38250uA for current-feedback */
	props.max_brightness = max_brightness;

	bl = devm_backlight_device_register(&pdev->dev,
				       su->type == AS3711_BL_SU1 ?
				       "as3711-su1" : "as3711-su2",
				       &pdev->dev, su,
				       &as3711_bl_ops, &props);
	if (IS_ERR(bl)) {
		dev_err(&pdev->dev, "failed to register backlight\n");
		return PTR_ERR(bl);
	}

	bl->props.brightness = props.max_brightness;

	backlight_update_status(bl);

	su->bl = bl;

	return 0;
}

static int as3711_backlight_parse_dt(struct device *dev)
{
	struct as3711_bl_pdata *pdata = dev_get_platdata(dev);
	struct device_node *bl =
		of_find_node_by_name(dev->parent->of_node, "backlight"), *fb;
	int ret;

	if (!bl) {
		dev_dbg(dev, "backlight node not found\n");
		return -ENODEV;
	}

	fb = of_parse_phandle(bl, "su1-dev", 0);
	if (fb) {
		pdata->su1_fb = fb->full_name;

		ret = of_property_read_u32(bl, "su1-max-uA", &pdata->su1_max_uA);
		if (pdata->su1_max_uA <= 0)
			ret = -EINVAL;
		if (ret < 0)
			return ret;
	}

	fb = of_parse_phandle(bl, "su2-dev", 0);
	if (fb) {
		int count = 0;

		pdata->su2_fb = fb->full_name;

		ret = of_property_read_u32(bl, "su2-max-uA", &pdata->su2_max_uA);
		if (pdata->su2_max_uA <= 0)
			ret = -EINVAL;
		if (ret < 0)
			return ret;

		if (of_find_property(bl, "su2-feedback-voltage", NULL)) {
			pdata->su2_feedback = AS3711_SU2_VOLTAGE;
			count++;
		}
		if (of_find_property(bl, "su2-feedback-curr1", NULL)) {
			pdata->su2_feedback = AS3711_SU2_CURR1;
			count++;
		}
		if (of_find_property(bl, "su2-feedback-curr2", NULL)) {
			pdata->su2_feedback = AS3711_SU2_CURR2;
			count++;
		}
		if (of_find_property(bl, "su2-feedback-curr3", NULL)) {
			pdata->su2_feedback = AS3711_SU2_CURR3;
			count++;
		}
		if (of_find_property(bl, "su2-feedback-curr-auto", NULL)) {
			pdata->su2_feedback = AS3711_SU2_CURR_AUTO;
			count++;
		}
		if (count != 1)
			return -EINVAL;

		count = 0;
		if (of_find_property(bl, "su2-fbprot-lx-sd4", NULL)) {
			pdata->su2_fbprot = AS3711_SU2_LX_SD4;
			count++;
		}
		if (of_find_property(bl, "su2-fbprot-gpio2", NULL)) {
			pdata->su2_fbprot = AS3711_SU2_GPIO2;
			count++;
		}
		if (of_find_property(bl, "su2-fbprot-gpio3", NULL)) {
			pdata->su2_fbprot = AS3711_SU2_GPIO3;
			count++;
		}
		if (of_find_property(bl, "su2-fbprot-gpio4", NULL)) {
			pdata->su2_fbprot = AS3711_SU2_GPIO4;
			count++;
		}
		if (count != 1)
			return -EINVAL;

		count = 0;
		if (of_find_property(bl, "su2-auto-curr1", NULL)) {
			pdata->su2_auto_curr1 = true;
			count++;
		}
		if (of_find_property(bl, "su2-auto-curr2", NULL)) {
			pdata->su2_auto_curr2 = true;
			count++;
		}
		if (of_find_property(bl, "su2-auto-curr3", NULL)) {
			pdata->su2_auto_curr3 = true;
			count++;
		}

		/*
		 * At least one su2-auto-curr* must be specified iff
		 * AS3711_SU2_CURR_AUTO is used
		 */
		if (!count ^ (pdata->su2_feedback != AS3711_SU2_CURR_AUTO))
			return -EINVAL;
	}

	return 0;
}

static int as3711_backlight_probe(struct platform_device *pdev)
{
	struct as3711_bl_pdata *pdata = dev_get_platdata(&pdev->dev);
	struct as3711 *as3711 = dev_get_drvdata(pdev->dev.parent);
	struct as3711_bl_supply *supply;
	struct as3711_bl_data *su;
	unsigned int max_brightness;
	int ret;

	if (!pdata) {
		dev_err(&pdev->dev, "No platform data, exiting...\n");
		return -ENODEV;
	}

	if (pdev->dev.parent->of_node) {
		ret = as3711_backlight_parse_dt(&pdev->dev);
		if (ret < 0) {
			dev_err(&pdev->dev, "DT parsing failed: %d\n", ret);
			return ret;
		}
	}

	if (!pdata->su1_fb && !pdata->su2_fb) {
		dev_err(&pdev->dev, "No framebuffer specified\n");
		return -EINVAL;
	}

	/*
	 * Due to possible hardware damage I chose to block all modes,
	 * unsupported on my hardware. Anyone, wishing to use any of those modes
	 * will have to first review the code, then activate and test it.
	 */
	if (pdata->su1_fb ||
	    pdata->su2_fbprot != AS3711_SU2_GPIO4 ||
	    pdata->su2_feedback != AS3711_SU2_CURR_AUTO) {
		dev_warn(&pdev->dev,
			 "Attention! An untested mode has been chosen!\n"
			 "Please, review the code, enable, test, and report success:-)\n");
		return -EINVAL;
	}

	supply = devm_kzalloc(&pdev->dev, sizeof(*supply), GFP_KERNEL);
	if (!supply)
		return -ENOMEM;

	supply->as3711 = as3711;
	supply->pdata = pdata;

	if (pdata->su1_fb) {
		su = &supply->su1;
		su->fb_name = pdata->su1_fb;
		su->type = AS3711_BL_SU1;

		max_brightness = min(pdata->su1_max_uA, 31);
		ret = as3711_bl_register(pdev, max_brightness, su);
		if (ret < 0)
			return ret;
	}

	if (pdata->su2_fb) {
		su = &supply->su2;
		su->fb_name = pdata->su2_fb;
		su->type = AS3711_BL_SU2;

		switch (pdata->su2_fbprot) {
		case AS3711_SU2_GPIO2:
		case AS3711_SU2_GPIO3:
		case AS3711_SU2_GPIO4:
		case AS3711_SU2_LX_SD4:
			break;
		default:
			return -EINVAL;
		}

		switch (pdata->su2_feedback) {
		case AS3711_SU2_VOLTAGE:
			max_brightness = min(pdata->su2_max_uA, 31);
			break;
		case AS3711_SU2_CURR1:
		case AS3711_SU2_CURR2:
		case AS3711_SU2_CURR3:
		case AS3711_SU2_CURR_AUTO:
			max_brightness = min(pdata->su2_max_uA / 150, 255);
			break;
		default:
			return -EINVAL;
		}

		ret = as3711_bl_init_su2(supply);
		if (ret < 0)
			return ret;

		ret = as3711_bl_register(pdev, max_brightness, su);
		if (ret < 0)
			return ret;
	}

	platform_set_drvdata(pdev, supply);

	return 0;
}

static struct platform_driver as3711_backlight_driver = {
	.driver		= {
		.name	= "as3711-backlight",
	},
	.probe		= as3711_backlight_probe,
};

module_platform_driver(as3711_backlight_driver);

MODULE_DESCRIPTION("Backlight Driver for AS3711 PMICs");
MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:as3711-backlight");