1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2011 ST-Ericsson SA.
4 * Copyright (C) 2009 Motorola, Inc.
5 *
6 * Simple driver for National Semiconductor LM3530 Backlight driver chip
7 *
8 * Author: Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>
9 * based on leds-lm3530.c by Dan Murphy <D.Murphy@motorola.com>
10 */
11
12#include <linux/i2c.h>
13#include <linux/leds.h>
14#include <linux/slab.h>
15#include <linux/platform_device.h>
16#include <linux/input.h>
17#include <linux/led-lm3530.h>
18#include <linux/types.h>
19#include <linux/regulator/consumer.h>
20#include <linux/module.h>
21
22#define LM3530_LED_DEV "lcd-backlight"
23#define LM3530_NAME "lm3530-led"
24
25#define LM3530_GEN_CONFIG		0x10
26#define LM3530_ALS_CONFIG		0x20
27#define LM3530_BRT_RAMP_RATE		0x30
28#define LM3530_ALS_IMP_SELECT		0x41
29#define LM3530_BRT_CTRL_REG		0xA0
30#define LM3530_ALS_ZB0_REG		0x60
31#define LM3530_ALS_ZB1_REG		0x61
32#define LM3530_ALS_ZB2_REG		0x62
33#define LM3530_ALS_ZB3_REG		0x63
34#define LM3530_ALS_Z0T_REG		0x70
35#define LM3530_ALS_Z1T_REG		0x71
36#define LM3530_ALS_Z2T_REG		0x72
37#define LM3530_ALS_Z3T_REG		0x73
38#define LM3530_ALS_Z4T_REG		0x74
39#define LM3530_REG_MAX			14
40
41/* General Control Register */
42#define LM3530_EN_I2C_SHIFT		(0)
43#define LM3530_RAMP_LAW_SHIFT		(1)
44#define LM3530_MAX_CURR_SHIFT		(2)
45#define LM3530_EN_PWM_SHIFT		(5)
46#define LM3530_PWM_POL_SHIFT		(6)
47#define LM3530_EN_PWM_SIMPLE_SHIFT	(7)
48
49#define LM3530_ENABLE_I2C		(1 << LM3530_EN_I2C_SHIFT)
50#define LM3530_ENABLE_PWM		(1 << LM3530_EN_PWM_SHIFT)
51#define LM3530_POL_LOW			(1 << LM3530_PWM_POL_SHIFT)
52#define LM3530_ENABLE_PWM_SIMPLE	(1 << LM3530_EN_PWM_SIMPLE_SHIFT)
53
54/* ALS Config Register Options */
55#define LM3530_ALS_AVG_TIME_SHIFT	(0)
56#define LM3530_EN_ALS_SHIFT		(3)
57#define LM3530_ALS_SEL_SHIFT		(5)
58
59#define LM3530_ENABLE_ALS		(3 << LM3530_EN_ALS_SHIFT)
60
61/* Brightness Ramp Rate Register */
62#define LM3530_BRT_RAMP_FALL_SHIFT	(0)
63#define LM3530_BRT_RAMP_RISE_SHIFT	(3)
64
65/* ALS Resistor Select */
66#define LM3530_ALS1_IMP_SHIFT		(0)
67#define LM3530_ALS2_IMP_SHIFT		(4)
68
69/* Zone Boundary Register defaults */
70#define LM3530_ALS_ZB_MAX		(4)
71#define LM3530_ALS_WINDOW_mV		(1000)
72#define LM3530_ALS_OFFSET_mV		(4)
73
74/* Zone Target Register defaults */
75#define LM3530_DEF_ZT_0			(0x7F)
76#define LM3530_DEF_ZT_1			(0x66)
77#define LM3530_DEF_ZT_2			(0x4C)
78#define LM3530_DEF_ZT_3			(0x33)
79#define LM3530_DEF_ZT_4			(0x19)
80
81/* 7 bits are used for the brightness : LM3530_BRT_CTRL_REG */
82#define MAX_BRIGHTNESS			(127)
83
84struct lm3530_mode_map {
85	const char *mode;
86	enum lm3530_mode mode_val;
87};
88
89static struct lm3530_mode_map mode_map[] = {
90	{ "man", LM3530_BL_MODE_MANUAL },
91	{ "als", LM3530_BL_MODE_ALS },
92	{ "pwm", LM3530_BL_MODE_PWM },
93};
94
95/**
96 * struct lm3530_data
97 * @led_dev: led class device
98 * @client: i2c client
99 * @pdata: LM3530 platform data
100 * @mode: mode of operation - manual, ALS, PWM
101 * @regulator: regulator
102 * @brightness: previous brightness value
103 * @enable: regulator is enabled
104 */
105struct lm3530_data {
106	struct led_classdev led_dev;
107	struct i2c_client *client;
108	struct lm3530_platform_data *pdata;
109	enum lm3530_mode mode;
110	struct regulator *regulator;
111	enum led_brightness brightness;
112	bool enable;
113};
114
115/*
116 * struct lm3530_als_data
117 * @config  : value of ALS configuration register
118 * @imp_sel : value of ALS resistor select register
119 * @zone    : values of ALS ZB(Zone Boundary) registers
120 */
121struct lm3530_als_data {
122	u8 config;
123	u8 imp_sel;
124	u8 zones[LM3530_ALS_ZB_MAX];
125};
126
127static const u8 lm3530_reg[LM3530_REG_MAX] = {
128	LM3530_GEN_CONFIG,
129	LM3530_ALS_CONFIG,
130	LM3530_BRT_RAMP_RATE,
131	LM3530_ALS_IMP_SELECT,
132	LM3530_BRT_CTRL_REG,
133	LM3530_ALS_ZB0_REG,
134	LM3530_ALS_ZB1_REG,
135	LM3530_ALS_ZB2_REG,
136	LM3530_ALS_ZB3_REG,
137	LM3530_ALS_Z0T_REG,
138	LM3530_ALS_Z1T_REG,
139	LM3530_ALS_Z2T_REG,
140	LM3530_ALS_Z3T_REG,
141	LM3530_ALS_Z4T_REG,
142};
143
144static int lm3530_get_mode_from_str(const char *str)
145{
146	int i;
147
148	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
149		if (sysfs_streq(str, mode_map[i].mode))
150			return mode_map[i].mode_val;
151
152	return -EINVAL;
153}
154
155static void lm3530_als_configure(struct lm3530_platform_data *pdata,
156				struct lm3530_als_data *als)
157{
158	int i;
159	u32 als_vmin, als_vmax, als_vstep;
160
161	if (pdata->als_vmax == 0) {
162		pdata->als_vmin = 0;
163		pdata->als_vmax = LM3530_ALS_WINDOW_mV;
164	}
165
166	als_vmin = pdata->als_vmin;
167	als_vmax = pdata->als_vmax;
168
169	if ((als_vmax - als_vmin) > LM3530_ALS_WINDOW_mV)
170		pdata->als_vmax = als_vmax = als_vmin + LM3530_ALS_WINDOW_mV;
171
172	/* n zone boundary makes n+1 zones */
173	als_vstep = (als_vmax - als_vmin) / (LM3530_ALS_ZB_MAX + 1);
174
175	for (i = 0; i < LM3530_ALS_ZB_MAX; i++)
176		als->zones[i] = (((als_vmin + LM3530_ALS_OFFSET_mV) +
177			als_vstep + (i * als_vstep)) * LED_FULL) / 1000;
178
179	als->config =
180		(pdata->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) |
181		(LM3530_ENABLE_ALS) |
182		(pdata->als_input_mode << LM3530_ALS_SEL_SHIFT);
183
184	als->imp_sel =
185		(pdata->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) |
186		(pdata->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT);
187}
188
189static int lm3530_led_enable(struct lm3530_data *drvdata)
190{
191	int ret;
192
193	if (drvdata->enable)
194		return 0;
195
196	ret = regulator_enable(drvdata->regulator);
197	if (ret) {
198		dev_err(drvdata->led_dev.dev, "Failed to enable vin:%d\n", ret);
199		return ret;
200	}
201
202	drvdata->enable = true;
203	return 0;
204}
205
206static void lm3530_led_disable(struct lm3530_data *drvdata)
207{
208	int ret;
209
210	if (!drvdata->enable)
211		return;
212
213	ret = regulator_disable(drvdata->regulator);
214	if (ret) {
215		dev_err(drvdata->led_dev.dev, "Failed to disable vin:%d\n",
216			ret);
217		return;
218	}
219
220	drvdata->enable = false;
221}
222
223static int lm3530_init_registers(struct lm3530_data *drvdata)
224{
225	int ret = 0;
226	int i;
227	u8 gen_config;
228	u8 brt_ramp;
229	u8 brightness;
230	u8 reg_val[LM3530_REG_MAX];
231	struct lm3530_platform_data *pdata = drvdata->pdata;
232	struct i2c_client *client = drvdata->client;
233	struct lm3530_pwm_data *pwm = &pdata->pwm_data;
234	struct lm3530_als_data als;
235
236	memset(&als, 0, sizeof(struct lm3530_als_data));
237
238	gen_config = (pdata->brt_ramp_law << LM3530_RAMP_LAW_SHIFT) |
239			((pdata->max_current & 7) << LM3530_MAX_CURR_SHIFT);
240
241	switch (drvdata->mode) {
242	case LM3530_BL_MODE_MANUAL:
243		gen_config |= LM3530_ENABLE_I2C;
244		break;
245	case LM3530_BL_MODE_ALS:
246		gen_config |= LM3530_ENABLE_I2C;
247		lm3530_als_configure(pdata, &als);
248		break;
249	case LM3530_BL_MODE_PWM:
250		gen_config |= LM3530_ENABLE_PWM | LM3530_ENABLE_PWM_SIMPLE |
251			      (pdata->pwm_pol_hi << LM3530_PWM_POL_SHIFT);
252		break;
253	}
254
255	brt_ramp = (pdata->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) |
256			(pdata->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT);
257
258	if (drvdata->brightness)
259		brightness = drvdata->brightness;
260	else
261		brightness = drvdata->brightness = pdata->brt_val;
262
263	if (brightness > drvdata->led_dev.max_brightness)
264		brightness = drvdata->led_dev.max_brightness;
265
266	reg_val[0] = gen_config;	/* LM3530_GEN_CONFIG */
267	reg_val[1] = als.config;	/* LM3530_ALS_CONFIG */
268	reg_val[2] = brt_ramp;		/* LM3530_BRT_RAMP_RATE */
269	reg_val[3] = als.imp_sel;	/* LM3530_ALS_IMP_SELECT */
270	reg_val[4] = brightness;	/* LM3530_BRT_CTRL_REG */
271	reg_val[5] = als.zones[0];	/* LM3530_ALS_ZB0_REG */
272	reg_val[6] = als.zones[1];	/* LM3530_ALS_ZB1_REG */
273	reg_val[7] = als.zones[2];	/* LM3530_ALS_ZB2_REG */
274	reg_val[8] = als.zones[3];	/* LM3530_ALS_ZB3_REG */
275	reg_val[9] = LM3530_DEF_ZT_0;	/* LM3530_ALS_Z0T_REG */
276	reg_val[10] = LM3530_DEF_ZT_1;	/* LM3530_ALS_Z1T_REG */
277	reg_val[11] = LM3530_DEF_ZT_2;	/* LM3530_ALS_Z2T_REG */
278	reg_val[12] = LM3530_DEF_ZT_3;	/* LM3530_ALS_Z3T_REG */
279	reg_val[13] = LM3530_DEF_ZT_4;	/* LM3530_ALS_Z4T_REG */
280
281	ret = lm3530_led_enable(drvdata);
282	if (ret)
283		return ret;
284
285	for (i = 0; i < LM3530_REG_MAX; i++) {
286		/* do not update brightness register when pwm mode */
287		if (lm3530_reg[i] == LM3530_BRT_CTRL_REG &&
288		    drvdata->mode == LM3530_BL_MODE_PWM) {
289			if (pwm->pwm_set_intensity)
290				pwm->pwm_set_intensity(reg_val[i],
291					drvdata->led_dev.max_brightness);
292			continue;
293		}
294
295		ret = i2c_smbus_write_byte_data(client,
296				lm3530_reg[i], reg_val[i]);
297		if (ret)
298			break;
299	}
300
301	return ret;
302}
303
304static void lm3530_brightness_set(struct led_classdev *led_cdev,
305				     enum led_brightness brt_val)
306{
307	int err;
308	struct lm3530_data *drvdata =
309	    container_of(led_cdev, struct lm3530_data, led_dev);
310	struct lm3530_platform_data *pdata = drvdata->pdata;
311	struct lm3530_pwm_data *pwm = &pdata->pwm_data;
312	u8 max_brightness = led_cdev->max_brightness;
313
314	switch (drvdata->mode) {
315	case LM3530_BL_MODE_MANUAL:
316
317		if (!drvdata->enable) {
318			err = lm3530_init_registers(drvdata);
319			if (err) {
320				dev_err(&drvdata->client->dev,
321					"Register Init failed: %d\n", err);
322				break;
323			}
324		}
325
326		/* set the brightness in brightness control register*/
327		err = i2c_smbus_write_byte_data(drvdata->client,
328				LM3530_BRT_CTRL_REG, brt_val);
329		if (err)
330			dev_err(&drvdata->client->dev,
331				"Unable to set brightness: %d\n", err);
332		else
333			drvdata->brightness = brt_val;
334
335		if (brt_val == 0)
336			lm3530_led_disable(drvdata);
337		break;
338	case LM3530_BL_MODE_ALS:
339		break;
340	case LM3530_BL_MODE_PWM:
341		if (pwm->pwm_set_intensity)
342			pwm->pwm_set_intensity(brt_val, max_brightness);
343		break;
344	default:
345		break;
346	}
347}
348
349static ssize_t mode_show(struct device *dev,
350			 struct device_attribute *attr, char *buf)
351{
352	struct led_classdev *led_cdev = dev_get_drvdata(dev);
353	struct lm3530_data *drvdata;
354	int i, len = 0;
355
356	drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
357	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
358		if (drvdata->mode == mode_map[i].mode_val)
359			len += sprintf(buf + len, "[%s] ", mode_map[i].mode);
360		else
361			len += sprintf(buf + len, "%s ", mode_map[i].mode);
362
363	len += sprintf(buf + len, "\n");
364
365	return len;
366}
367
368static ssize_t mode_store(struct device *dev, struct device_attribute
369			  *attr, const char *buf, size_t size)
370{
371	struct led_classdev *led_cdev = dev_get_drvdata(dev);
372	struct lm3530_data *drvdata;
373	struct lm3530_pwm_data *pwm;
374	u8 max_brightness;
375	int mode, err;
376
377	drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
378	pwm = &drvdata->pdata->pwm_data;
379	max_brightness = led_cdev->max_brightness;
380	mode = lm3530_get_mode_from_str(buf);
381	if (mode < 0) {
382		dev_err(dev, "Invalid mode\n");
383		return mode;
384	}
385
386	drvdata->mode = mode;
387
388	/* set pwm to low if unnecessary */
389	if (mode != LM3530_BL_MODE_PWM && pwm->pwm_set_intensity)
390		pwm->pwm_set_intensity(0, max_brightness);
391
392	err = lm3530_init_registers(drvdata);
393	if (err) {
394		dev_err(dev, "Setting %s Mode failed :%d\n", buf, err);
395		return err;
396	}
397
398	return sizeof(drvdata->mode);
399}
400static DEVICE_ATTR_RW(mode);
401
402static struct attribute *lm3530_attrs[] = {
403	&dev_attr_mode.attr,
404	NULL
405};
406ATTRIBUTE_GROUPS(lm3530);
407
408static int lm3530_probe(struct i2c_client *client)
409{
410	struct lm3530_platform_data *pdata = dev_get_platdata(&client->dev);
411	struct lm3530_data *drvdata;
412	int err = 0;
413
414	if (pdata == NULL) {
415		dev_err(&client->dev, "platform data required\n");
416		return -ENODEV;
417	}
418
419	/* BL mode */
420	if (pdata->mode > LM3530_BL_MODE_PWM) {
421		dev_err(&client->dev, "Illegal Mode request\n");
422		return -EINVAL;
423	}
424
425	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
426		dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
427		return -EIO;
428	}
429
430	drvdata = devm_kzalloc(&client->dev, sizeof(struct lm3530_data),
431				GFP_KERNEL);
432	if (drvdata == NULL)
433		return -ENOMEM;
434
435	drvdata->mode = pdata->mode;
436	drvdata->client = client;
437	drvdata->pdata = pdata;
438	drvdata->brightness = LED_OFF;
439	drvdata->enable = false;
440	drvdata->led_dev.name = LM3530_LED_DEV;
441	drvdata->led_dev.brightness_set = lm3530_brightness_set;
442	drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
443	drvdata->led_dev.groups = lm3530_groups;
444
445	i2c_set_clientdata(client, drvdata);
446
447	drvdata->regulator = devm_regulator_get(&client->dev, "vin");
448	if (IS_ERR(drvdata->regulator)) {
449		dev_err(&client->dev, "regulator get failed\n");
450		err = PTR_ERR(drvdata->regulator);
451		drvdata->regulator = NULL;
452		return err;
453	}
454
455	if (drvdata->pdata->brt_val) {
456		err = lm3530_init_registers(drvdata);
457		if (err < 0) {
458			dev_err(&client->dev,
459				"Register Init failed: %d\n", err);
460			return err;
461		}
462	}
463	err = led_classdev_register(&client->dev, &drvdata->led_dev);
464	if (err < 0) {
465		dev_err(&client->dev, "Register led class failed: %d\n", err);
466		return err;
467	}
468
469	return 0;
470}
471
472static void lm3530_remove(struct i2c_client *client)
473{
474	struct lm3530_data *drvdata = i2c_get_clientdata(client);
475
476	lm3530_led_disable(drvdata);
477	led_classdev_unregister(&drvdata->led_dev);
478}
479
480static const struct i2c_device_id lm3530_id[] = {
481	{LM3530_NAME, 0},
482	{}
483};
484MODULE_DEVICE_TABLE(i2c, lm3530_id);
485
486static struct i2c_driver lm3530_i2c_driver = {
487	.probe = lm3530_probe,
488	.remove = lm3530_remove,
489	.id_table = lm3530_id,
490	.driver = {
491		.name = LM3530_NAME,
492	},
493};
494
495module_i2c_driver(lm3530_i2c_driver);
496
497MODULE_DESCRIPTION("Back Light driver for LM3530");
498MODULE_LICENSE("GPL v2");
499MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");
500