1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * TI LP855x Backlight Driver
4 *
5 *			Copyright (C) 2011 Texas Instruments
6 */
7
8#include <linux/module.h>
9#include <linux/slab.h>
10#include <linux/i2c.h>
11#include <linux/backlight.h>
12#include <linux/delay.h>
13#include <linux/err.h>
14#include <linux/of.h>
15#include <linux/platform_data/lp855x.h>
16#include <linux/pwm.h>
17#include <linux/regulator/consumer.h>
18
19/* LP8550/1/2/3/6 Registers */
20#define LP855X_BRIGHTNESS_CTRL		0x00
21#define LP855X_DEVICE_CTRL		0x01
22#define LP855X_EEPROM_START		0xA0
23#define LP855X_EEPROM_END		0xA7
24#define LP8556_EPROM_START		0xA0
25#define LP8556_EPROM_END		0xAF
26
27/* LP8555/7 Registers */
28#define LP8557_BL_CMD			0x00
29#define LP8557_BL_MASK			0x01
30#define LP8557_BL_ON			0x01
31#define LP8557_BL_OFF			0x00
32#define LP8557_BRIGHTNESS_CTRL		0x04
33#define LP8557_CONFIG			0x10
34#define LP8555_EPROM_START		0x10
35#define LP8555_EPROM_END		0x7A
36#define LP8557_EPROM_START		0x10
37#define LP8557_EPROM_END		0x1E
38
39#define DEFAULT_BL_NAME		"lcd-backlight"
40#define MAX_BRIGHTNESS		255
41
42enum lp855x_brightness_ctrl_mode {
43	PWM_BASED = 1,
44	REGISTER_BASED,
45};
46
47struct lp855x;
48
49/*
50 * struct lp855x_device_config
51 * @pre_init_device: init device function call before updating the brightness
52 * @reg_brightness: register address for brigthenss control
53 * @reg_devicectrl: register address for device control
54 * @post_init_device: late init device function call
55 */
56struct lp855x_device_config {
57	int (*pre_init_device)(struct lp855x *);
58	u8 reg_brightness;
59	u8 reg_devicectrl;
60	int (*post_init_device)(struct lp855x *);
61};
62
63struct lp855x {
64	const char *chipname;
65	enum lp855x_chip_id chip_id;
66	enum lp855x_brightness_ctrl_mode mode;
67	struct lp855x_device_config *cfg;
68	struct i2c_client *client;
69	struct backlight_device *bl;
70	struct device *dev;
71	struct lp855x_platform_data *pdata;
72	struct pwm_device *pwm;
73	struct regulator *supply;	/* regulator for VDD input */
74	struct regulator *enable;	/* regulator for EN/VDDIO input */
75};
76
77static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
78{
79	return i2c_smbus_write_byte_data(lp->client, reg, data);
80}
81
82static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
83{
84	int ret;
85	u8 tmp;
86
87	ret = i2c_smbus_read_byte_data(lp->client, reg);
88	if (ret < 0) {
89		dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
90		return ret;
91	}
92
93	tmp = (u8)ret;
94	tmp &= ~mask;
95	tmp |= data & mask;
96
97	return lp855x_write_byte(lp, reg, tmp);
98}
99
100static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
101{
102	u8 start, end;
103
104	switch (lp->chip_id) {
105	case LP8550:
106	case LP8551:
107	case LP8552:
108	case LP8553:
109		start = LP855X_EEPROM_START;
110		end = LP855X_EEPROM_END;
111		break;
112	case LP8556:
113		start = LP8556_EPROM_START;
114		end = LP8556_EPROM_END;
115		break;
116	case LP8555:
117		start = LP8555_EPROM_START;
118		end = LP8555_EPROM_END;
119		break;
120	case LP8557:
121		start = LP8557_EPROM_START;
122		end = LP8557_EPROM_END;
123		break;
124	default:
125		return false;
126	}
127
128	return addr >= start && addr <= end;
129}
130
131static int lp8557_bl_off(struct lp855x *lp)
132{
133	/* BL_ON = 0 before updating EPROM settings */
134	return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
135				LP8557_BL_OFF);
136}
137
138static int lp8557_bl_on(struct lp855x *lp)
139{
140	/* BL_ON = 1 after updating EPROM settings */
141	return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
142				LP8557_BL_ON);
143}
144
145static struct lp855x_device_config lp855x_dev_cfg = {
146	.reg_brightness = LP855X_BRIGHTNESS_CTRL,
147	.reg_devicectrl = LP855X_DEVICE_CTRL,
148};
149
150static struct lp855x_device_config lp8557_dev_cfg = {
151	.reg_brightness = LP8557_BRIGHTNESS_CTRL,
152	.reg_devicectrl = LP8557_CONFIG,
153	.pre_init_device = lp8557_bl_off,
154	.post_init_device = lp8557_bl_on,
155};
156
157/*
158 * Device specific configuration flow
159 *
160 *    a) pre_init_device(optional)
161 *    b) update the brightness register
162 *    c) update device control register
163 *    d) update ROM area(optional)
164 *    e) post_init_device(optional)
165 *
166 */
167static int lp855x_configure(struct lp855x *lp)
168{
169	u8 val, addr;
170	int i, ret;
171	struct lp855x_platform_data *pd = lp->pdata;
172
173	switch (lp->chip_id) {
174	case LP8550:
175	case LP8551:
176	case LP8552:
177	case LP8553:
178	case LP8556:
179		lp->cfg = &lp855x_dev_cfg;
180		break;
181	case LP8555:
182	case LP8557:
183		lp->cfg = &lp8557_dev_cfg;
184		break;
185	default:
186		return -EINVAL;
187	}
188
189	if (lp->cfg->pre_init_device) {
190		ret = lp->cfg->pre_init_device(lp);
191		if (ret) {
192			dev_err(lp->dev, "pre init device err: %d\n", ret);
193			goto err;
194		}
195	}
196
197	val = pd->initial_brightness;
198	ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
199	if (ret)
200		goto err;
201
202	val = pd->device_control;
203	ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
204	if (ret)
205		goto err;
206
207	if (pd->size_program > 0) {
208		for (i = 0; i < pd->size_program; i++) {
209			addr = pd->rom_data[i].addr;
210			val = pd->rom_data[i].val;
211			if (!lp855x_is_valid_rom_area(lp, addr))
212				continue;
213
214			ret = lp855x_write_byte(lp, addr, val);
215			if (ret)
216				goto err;
217		}
218	}
219
220	if (lp->cfg->post_init_device) {
221		ret = lp->cfg->post_init_device(lp);
222		if (ret) {
223			dev_err(lp->dev, "post init device err: %d\n", ret);
224			goto err;
225		}
226	}
227
228	return 0;
229
230err:
231	return ret;
232}
233
234static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
235{
236	unsigned int period = lp->pdata->period_ns;
237	unsigned int duty = br * period / max_br;
238	struct pwm_device *pwm;
239
240	/* request pwm device with the consumer name */
241	if (!lp->pwm) {
242		pwm = devm_pwm_get(lp->dev, lp->chipname);
243		if (IS_ERR(pwm))
244			return;
245
246		lp->pwm = pwm;
247
248		/*
249		 * FIXME: pwm_apply_args() should be removed when switching to
250		 * the atomic PWM API.
251		 */
252		pwm_apply_args(pwm);
253	}
254
255	pwm_config(lp->pwm, duty, period);
256	if (duty)
257		pwm_enable(lp->pwm);
258	else
259		pwm_disable(lp->pwm);
260}
261
262static int lp855x_bl_update_status(struct backlight_device *bl)
263{
264	struct lp855x *lp = bl_get_data(bl);
265	int brightness = bl->props.brightness;
266
267	if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
268		brightness = 0;
269
270	if (lp->mode == PWM_BASED)
271		lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness);
272	else if (lp->mode == REGISTER_BASED)
273		lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness);
274
275	return 0;
276}
277
278static const struct backlight_ops lp855x_bl_ops = {
279	.options = BL_CORE_SUSPENDRESUME,
280	.update_status = lp855x_bl_update_status,
281};
282
283static int lp855x_backlight_register(struct lp855x *lp)
284{
285	struct backlight_device *bl;
286	struct backlight_properties props;
287	struct lp855x_platform_data *pdata = lp->pdata;
288	const char *name = pdata->name ? : DEFAULT_BL_NAME;
289
290	memset(&props, 0, sizeof(props));
291	props.type = BACKLIGHT_PLATFORM;
292	props.max_brightness = MAX_BRIGHTNESS;
293
294	if (pdata->initial_brightness > props.max_brightness)
295		pdata->initial_brightness = props.max_brightness;
296
297	props.brightness = pdata->initial_brightness;
298
299	bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
300				       &lp855x_bl_ops, &props);
301	if (IS_ERR(bl))
302		return PTR_ERR(bl);
303
304	lp->bl = bl;
305
306	return 0;
307}
308
309static ssize_t lp855x_get_chip_id(struct device *dev,
310				struct device_attribute *attr, char *buf)
311{
312	struct lp855x *lp = dev_get_drvdata(dev);
313
314	return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
315}
316
317static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
318				     struct device_attribute *attr, char *buf)
319{
320	struct lp855x *lp = dev_get_drvdata(dev);
321	char *strmode = NULL;
322
323	if (lp->mode == PWM_BASED)
324		strmode = "pwm based";
325	else if (lp->mode == REGISTER_BASED)
326		strmode = "register based";
327
328	return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
329}
330
331static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
332static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
333
334static struct attribute *lp855x_attributes[] = {
335	&dev_attr_chip_id.attr,
336	&dev_attr_bl_ctl_mode.attr,
337	NULL,
338};
339
340static const struct attribute_group lp855x_attr_group = {
341	.attrs = lp855x_attributes,
342};
343
344#ifdef CONFIG_OF
345static int lp855x_parse_dt(struct lp855x *lp)
346{
347	struct device *dev = lp->dev;
348	struct device_node *node = dev->of_node;
349	struct lp855x_platform_data *pdata;
350	int rom_length;
351
352	if (!node) {
353		dev_err(dev, "no platform data\n");
354		return -EINVAL;
355	}
356
357	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
358	if (!pdata)
359		return -ENOMEM;
360
361	of_property_read_string(node, "bl-name", &pdata->name);
362	of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
363	of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
364	of_property_read_u32(node, "pwm-period", &pdata->period_ns);
365
366	/* Fill ROM platform data if defined */
367	rom_length = of_get_child_count(node);
368	if (rom_length > 0) {
369		struct lp855x_rom_data *rom;
370		struct device_node *child;
371		int i = 0;
372
373		rom = devm_kcalloc(dev, rom_length, sizeof(*rom), GFP_KERNEL);
374		if (!rom)
375			return -ENOMEM;
376
377		for_each_child_of_node(node, child) {
378			of_property_read_u8(child, "rom-addr", &rom[i].addr);
379			of_property_read_u8(child, "rom-val", &rom[i].val);
380			i++;
381		}
382
383		pdata->size_program = rom_length;
384		pdata->rom_data = &rom[0];
385	}
386
387	lp->pdata = pdata;
388
389	return 0;
390}
391#else
392static int lp855x_parse_dt(struct lp855x *lp)
393{
394	return -EINVAL;
395}
396#endif
397
398static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
399{
400	struct lp855x *lp;
401	int ret;
402
403	if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
404		return -EIO;
405
406	lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
407	if (!lp)
408		return -ENOMEM;
409
410	lp->client = cl;
411	lp->dev = &cl->dev;
412	lp->chipname = id->name;
413	lp->chip_id = id->driver_data;
414	lp->pdata = dev_get_platdata(&cl->dev);
415
416	if (!lp->pdata) {
417		ret = lp855x_parse_dt(lp);
418		if (ret < 0)
419			return ret;
420	}
421
422	if (lp->pdata->period_ns > 0)
423		lp->mode = PWM_BASED;
424	else
425		lp->mode = REGISTER_BASED;
426
427	lp->supply = devm_regulator_get(lp->dev, "power");
428	if (IS_ERR(lp->supply)) {
429		if (PTR_ERR(lp->supply) == -EPROBE_DEFER)
430			return -EPROBE_DEFER;
431		lp->supply = NULL;
432	}
433
434	lp->enable = devm_regulator_get_optional(lp->dev, "enable");
435	if (IS_ERR(lp->enable)) {
436		ret = PTR_ERR(lp->enable);
437		if (ret == -ENODEV) {
438			lp->enable = NULL;
439		} else {
440			if (ret != -EPROBE_DEFER)
441				dev_err(lp->dev, "error getting enable regulator: %d\n",
442					ret);
443			return ret;
444		}
445	}
446
447	if (lp->supply) {
448		ret = regulator_enable(lp->supply);
449		if (ret < 0) {
450			dev_err(&cl->dev, "failed to enable supply: %d\n", ret);
451			return ret;
452		}
453	}
454
455	if (lp->enable) {
456		ret = regulator_enable(lp->enable);
457		if (ret < 0) {
458			dev_err(lp->dev, "failed to enable vddio: %d\n", ret);
459			goto disable_supply;
460		}
461
462		/*
463		 * LP8555 datasheet says t_RESPONSE (time between VDDIO and
464		 * I2C) is 1ms.
465		 */
466		usleep_range(1000, 2000);
467	}
468
469	i2c_set_clientdata(cl, lp);
470
471	ret = lp855x_configure(lp);
472	if (ret) {
473		dev_err(lp->dev, "device config err: %d", ret);
474		goto disable_vddio;
475	}
476
477	ret = lp855x_backlight_register(lp);
478	if (ret) {
479		dev_err(lp->dev,
480			"failed to register backlight. err: %d\n", ret);
481		goto disable_vddio;
482	}
483
484	ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
485	if (ret) {
486		dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
487		goto disable_vddio;
488	}
489
490	backlight_update_status(lp->bl);
491
492	return 0;
493
494disable_vddio:
495	if (lp->enable)
496		regulator_disable(lp->enable);
497disable_supply:
498	if (lp->supply)
499		regulator_disable(lp->supply);
500
501	return ret;
502}
503
504static int lp855x_remove(struct i2c_client *cl)
505{
506	struct lp855x *lp = i2c_get_clientdata(cl);
507
508	lp->bl->props.brightness = 0;
509	backlight_update_status(lp->bl);
510	if (lp->enable)
511		regulator_disable(lp->enable);
512	if (lp->supply)
513		regulator_disable(lp->supply);
514	sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
515
516	return 0;
517}
518
519static const struct of_device_id lp855x_dt_ids[] = {
520	{ .compatible = "ti,lp8550", },
521	{ .compatible = "ti,lp8551", },
522	{ .compatible = "ti,lp8552", },
523	{ .compatible = "ti,lp8553", },
524	{ .compatible = "ti,lp8555", },
525	{ .compatible = "ti,lp8556", },
526	{ .compatible = "ti,lp8557", },
527	{ }
528};
529MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
530
531static const struct i2c_device_id lp855x_ids[] = {
532	{"lp8550", LP8550},
533	{"lp8551", LP8551},
534	{"lp8552", LP8552},
535	{"lp8553", LP8553},
536	{"lp8555", LP8555},
537	{"lp8556", LP8556},
538	{"lp8557", LP8557},
539	{ }
540};
541MODULE_DEVICE_TABLE(i2c, lp855x_ids);
542
543static struct i2c_driver lp855x_driver = {
544	.driver = {
545		   .name = "lp855x",
546		   .of_match_table = of_match_ptr(lp855x_dt_ids),
547		   },
548	.probe = lp855x_probe,
549	.remove = lp855x_remove,
550	.id_table = lp855x_ids,
551};
552
553module_i2c_driver(lp855x_driver);
554
555MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
556MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
557MODULE_LICENSE("GPL");
558