1/*
2 * Copyright (C) 2011 ST-Ericsson SA.
3 * Copyright (C) 2009 Motorola, Inc.
4 *
5 * License Terms: GNU General Public License v2
6 *
7 * Simple driver for National Semiconductor LM3530 Backlight driver chip
8 *
9 * Author: Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>
10 * based on leds-lm3530.c by Dan Murphy <D.Murphy@motorola.com>
11 */
12
13#include <linux/i2c.h>
14#include <linux/leds.h>
15#include <linux/slab.h>
16#include <linux/platform_device.h>
17#include <linux/input.h>
18#include <linux/led-lm3530.h>
19#include <linux/types.h>
20#include <linux/regulator/consumer.h>
21#include <linux/module.h>
22
23#define LM3530_LED_DEV "lcd-backlight"
24#define LM3530_NAME "lm3530-led"
25
26#define LM3530_GEN_CONFIG		0x10
27#define LM3530_ALS_CONFIG		0x20
28#define LM3530_BRT_RAMP_RATE		0x30
29#define LM3530_ALS_IMP_SELECT		0x41
30#define LM3530_BRT_CTRL_REG		0xA0
31#define LM3530_ALS_ZB0_REG		0x60
32#define LM3530_ALS_ZB1_REG		0x61
33#define LM3530_ALS_ZB2_REG		0x62
34#define LM3530_ALS_ZB3_REG		0x63
35#define LM3530_ALS_Z0T_REG		0x70
36#define LM3530_ALS_Z1T_REG		0x71
37#define LM3530_ALS_Z2T_REG		0x72
38#define LM3530_ALS_Z3T_REG		0x73
39#define LM3530_ALS_Z4T_REG		0x74
40#define LM3530_REG_MAX			14
41
42/* General Control Register */
43#define LM3530_EN_I2C_SHIFT		(0)
44#define LM3530_RAMP_LAW_SHIFT		(1)
45#define LM3530_MAX_CURR_SHIFT		(2)
46#define LM3530_EN_PWM_SHIFT		(5)
47#define LM3530_PWM_POL_SHIFT		(6)
48#define LM3530_EN_PWM_SIMPLE_SHIFT	(7)
49
50#define LM3530_ENABLE_I2C		(1 << LM3530_EN_I2C_SHIFT)
51#define LM3530_ENABLE_PWM		(1 << LM3530_EN_PWM_SHIFT)
52#define LM3530_POL_LOW			(1 << LM3530_PWM_POL_SHIFT)
53#define LM3530_ENABLE_PWM_SIMPLE	(1 << LM3530_EN_PWM_SIMPLE_SHIFT)
54
55/* ALS Config Register Options */
56#define LM3530_ALS_AVG_TIME_SHIFT	(0)
57#define LM3530_EN_ALS_SHIFT		(3)
58#define LM3530_ALS_SEL_SHIFT		(5)
59
60#define LM3530_ENABLE_ALS		(3 << LM3530_EN_ALS_SHIFT)
61
62/* Brightness Ramp Rate Register */
63#define LM3530_BRT_RAMP_FALL_SHIFT	(0)
64#define LM3530_BRT_RAMP_RISE_SHIFT	(3)
65
66/* ALS Resistor Select */
67#define LM3530_ALS1_IMP_SHIFT		(0)
68#define LM3530_ALS2_IMP_SHIFT		(4)
69
70/* Zone Boundary Register defaults */
71#define LM3530_ALS_ZB_MAX		(4)
72#define LM3530_ALS_WINDOW_mV		(1000)
73#define LM3530_ALS_OFFSET_mV		(4)
74
75/* Zone Target Register defaults */
76#define LM3530_DEF_ZT_0			(0x7F)
77#define LM3530_DEF_ZT_1			(0x66)
78#define LM3530_DEF_ZT_2			(0x4C)
79#define LM3530_DEF_ZT_3			(0x33)
80#define LM3530_DEF_ZT_4			(0x19)
81
82/* 7 bits are used for the brightness : LM3530_BRT_CTRL_REG */
83#define MAX_BRIGHTNESS			(127)
84
85struct lm3530_mode_map {
86	const char *mode;
87	enum lm3530_mode mode_val;
88};
89
90static struct lm3530_mode_map mode_map[] = {
91	{ "man", LM3530_BL_MODE_MANUAL },
92	{ "als", LM3530_BL_MODE_ALS },
93	{ "pwm", LM3530_BL_MODE_PWM },
94};
95
96/**
97 * struct lm3530_data
98 * @led_dev: led class device
99 * @client: i2c client
100 * @pdata: LM3530 platform data
101 * @mode: mode of operation - manual, ALS, PWM
102 * @regulator: regulator
103 * @brighness: previous brightness value
104 * @enable: regulator is enabled
105 */
106struct lm3530_data {
107	struct led_classdev led_dev;
108	struct i2c_client *client;
109	struct lm3530_platform_data *pdata;
110	enum lm3530_mode mode;
111	struct regulator *regulator;
112	enum led_brightness brightness;
113	bool enable;
114};
115
116/*
117 * struct lm3530_als_data
118 * @config  : value of ALS configuration register
119 * @imp_sel : value of ALS resistor select register
120 * @zone    : values of ALS ZB(Zone Boundary) registers
121 */
122struct lm3530_als_data {
123	u8 config;
124	u8 imp_sel;
125	u8 zones[LM3530_ALS_ZB_MAX];
126};
127
128static const u8 lm3530_reg[LM3530_REG_MAX] = {
129	LM3530_GEN_CONFIG,
130	LM3530_ALS_CONFIG,
131	LM3530_BRT_RAMP_RATE,
132	LM3530_ALS_IMP_SELECT,
133	LM3530_BRT_CTRL_REG,
134	LM3530_ALS_ZB0_REG,
135	LM3530_ALS_ZB1_REG,
136	LM3530_ALS_ZB2_REG,
137	LM3530_ALS_ZB3_REG,
138	LM3530_ALS_Z0T_REG,
139	LM3530_ALS_Z1T_REG,
140	LM3530_ALS_Z2T_REG,
141	LM3530_ALS_Z3T_REG,
142	LM3530_ALS_Z4T_REG,
143};
144
145static int lm3530_get_mode_from_str(const char *str)
146{
147	int i;
148
149	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
150		if (sysfs_streq(str, mode_map[i].mode))
151			return mode_map[i].mode_val;
152
153	return -EINVAL;
154}
155
156static void lm3530_als_configure(struct lm3530_platform_data *pdata,
157				struct lm3530_als_data *als)
158{
159	int i;
160	u32 als_vmin, als_vmax, als_vstep;
161
162	if (pdata->als_vmax == 0) {
163		pdata->als_vmin = 0;
164		pdata->als_vmax = LM3530_ALS_WINDOW_mV;
165	}
166
167	als_vmin = pdata->als_vmin;
168	als_vmax = pdata->als_vmax;
169
170	if ((als_vmax - als_vmin) > LM3530_ALS_WINDOW_mV)
171		pdata->als_vmax = als_vmax = als_vmin + LM3530_ALS_WINDOW_mV;
172
173	/* n zone boundary makes n+1 zones */
174	als_vstep = (als_vmax - als_vmin) / (LM3530_ALS_ZB_MAX + 1);
175
176	for (i = 0; i < LM3530_ALS_ZB_MAX; i++)
177		als->zones[i] = (((als_vmin + LM3530_ALS_OFFSET_mV) +
178			als_vstep + (i * als_vstep)) * LED_FULL) / 1000;
179
180	als->config =
181		(pdata->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) |
182		(LM3530_ENABLE_ALS) |
183		(pdata->als_input_mode << LM3530_ALS_SEL_SHIFT);
184
185	als->imp_sel =
186		(pdata->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) |
187		(pdata->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT);
188}
189
190static int lm3530_led_enable(struct lm3530_data *drvdata)
191{
192	int ret;
193
194	if (drvdata->enable)
195		return 0;
196
197	ret = regulator_enable(drvdata->regulator);
198	if (ret) {
199		dev_err(drvdata->led_dev.dev, "Failed to enable vin:%d\n", ret);
200		return ret;
201	}
202
203	drvdata->enable = true;
204	return 0;
205}
206
207static void lm3530_led_disable(struct lm3530_data *drvdata)
208{
209	int ret;
210
211	if (!drvdata->enable)
212		return;
213
214	ret = regulator_disable(drvdata->regulator);
215	if (ret) {
216		dev_err(drvdata->led_dev.dev, "Failed to disable vin:%d\n",
217			ret);
218		return;
219	}
220
221	drvdata->enable = false;
222}
223
224static int lm3530_init_registers(struct lm3530_data *drvdata)
225{
226	int ret = 0;
227	int i;
228	u8 gen_config;
229	u8 brt_ramp;
230	u8 brightness;
231	u8 reg_val[LM3530_REG_MAX];
232	struct lm3530_platform_data *pdata = drvdata->pdata;
233	struct i2c_client *client = drvdata->client;
234	struct lm3530_pwm_data *pwm = &pdata->pwm_data;
235	struct lm3530_als_data als;
236
237	memset(&als, 0, sizeof(struct lm3530_als_data));
238
239	gen_config = (pdata->brt_ramp_law << LM3530_RAMP_LAW_SHIFT) |
240			((pdata->max_current & 7) << LM3530_MAX_CURR_SHIFT);
241
242	switch (drvdata->mode) {
243	case LM3530_BL_MODE_MANUAL:
244		gen_config |= LM3530_ENABLE_I2C;
245		break;
246	case LM3530_BL_MODE_ALS:
247		gen_config |= LM3530_ENABLE_I2C;
248		lm3530_als_configure(pdata, &als);
249		break;
250	case LM3530_BL_MODE_PWM:
251		gen_config |= LM3530_ENABLE_PWM | LM3530_ENABLE_PWM_SIMPLE |
252			      (pdata->pwm_pol_hi << LM3530_PWM_POL_SHIFT);
253		break;
254	}
255
256	brt_ramp = (pdata->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) |
257			(pdata->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT);
258
259	if (drvdata->brightness)
260		brightness = drvdata->brightness;
261	else
262		brightness = drvdata->brightness = pdata->brt_val;
263
264	if (brightness > drvdata->led_dev.max_brightness)
265		brightness = drvdata->led_dev.max_brightness;
266
267	reg_val[0] = gen_config;	/* LM3530_GEN_CONFIG */
268	reg_val[1] = als.config;	/* LM3530_ALS_CONFIG */
269	reg_val[2] = brt_ramp;		/* LM3530_BRT_RAMP_RATE */
270	reg_val[3] = als.imp_sel;	/* LM3530_ALS_IMP_SELECT */
271	reg_val[4] = brightness;	/* LM3530_BRT_CTRL_REG */
272	reg_val[5] = als.zones[0];	/* LM3530_ALS_ZB0_REG */
273	reg_val[6] = als.zones[1];	/* LM3530_ALS_ZB1_REG */
274	reg_val[7] = als.zones[2];	/* LM3530_ALS_ZB2_REG */
275	reg_val[8] = als.zones[3];	/* LM3530_ALS_ZB3_REG */
276	reg_val[9] = LM3530_DEF_ZT_0;	/* LM3530_ALS_Z0T_REG */
277	reg_val[10] = LM3530_DEF_ZT_1;	/* LM3530_ALS_Z1T_REG */
278	reg_val[11] = LM3530_DEF_ZT_2;	/* LM3530_ALS_Z2T_REG */
279	reg_val[12] = LM3530_DEF_ZT_3;	/* LM3530_ALS_Z3T_REG */
280	reg_val[13] = LM3530_DEF_ZT_4;	/* LM3530_ALS_Z4T_REG */
281
282	ret = lm3530_led_enable(drvdata);
283	if (ret)
284		return ret;
285
286	for (i = 0; i < LM3530_REG_MAX; i++) {
287		/* do not update brightness register when pwm mode */
288		if (lm3530_reg[i] == LM3530_BRT_CTRL_REG &&
289		    drvdata->mode == LM3530_BL_MODE_PWM) {
290			if (pwm->pwm_set_intensity)
291				pwm->pwm_set_intensity(reg_val[i],
292					drvdata->led_dev.max_brightness);
293			continue;
294		}
295
296		ret = i2c_smbus_write_byte_data(client,
297				lm3530_reg[i], reg_val[i]);
298		if (ret)
299			break;
300	}
301
302	return ret;
303}
304
305static void lm3530_brightness_set(struct led_classdev *led_cdev,
306				     enum led_brightness brt_val)
307{
308	int err;
309	struct lm3530_data *drvdata =
310	    container_of(led_cdev, struct lm3530_data, led_dev);
311	struct lm3530_platform_data *pdata = drvdata->pdata;
312	struct lm3530_pwm_data *pwm = &pdata->pwm_data;
313	u8 max_brightness = led_cdev->max_brightness;
314
315	switch (drvdata->mode) {
316	case LM3530_BL_MODE_MANUAL:
317
318		if (!drvdata->enable) {
319			err = lm3530_init_registers(drvdata);
320			if (err) {
321				dev_err(&drvdata->client->dev,
322					"Register Init failed: %d\n", err);
323				break;
324			}
325		}
326
327		/* set the brightness in brightness control register*/
328		err = i2c_smbus_write_byte_data(drvdata->client,
329				LM3530_BRT_CTRL_REG, brt_val);
330		if (err)
331			dev_err(&drvdata->client->dev,
332				"Unable to set brightness: %d\n", err);
333		else
334			drvdata->brightness = brt_val;
335
336		if (brt_val == 0)
337			lm3530_led_disable(drvdata);
338		break;
339	case LM3530_BL_MODE_ALS:
340		break;
341	case LM3530_BL_MODE_PWM:
342		if (pwm->pwm_set_intensity)
343			pwm->pwm_set_intensity(brt_val, max_brightness);
344		break;
345	default:
346		break;
347	}
348}
349
350static ssize_t lm3530_mode_get(struct device *dev,
351		struct device_attribute *attr, char *buf)
352{
353	struct led_classdev *led_cdev = dev_get_drvdata(dev);
354	struct lm3530_data *drvdata;
355	int i, len = 0;
356
357	drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
358	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
359		if (drvdata->mode == mode_map[i].mode_val)
360			len += sprintf(buf + len, "[%s] ", mode_map[i].mode);
361		else
362			len += sprintf(buf + len, "%s ", mode_map[i].mode);
363
364	len += sprintf(buf + len, "\n");
365
366	return len;
367}
368
369static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
370				   *attr, const char *buf, size_t size)
371{
372	struct led_classdev *led_cdev = dev_get_drvdata(dev);
373	struct lm3530_data *drvdata;
374	struct lm3530_pwm_data *pwm;
375	u8 max_brightness;
376	int mode, err;
377
378	drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
379	pwm = &drvdata->pdata->pwm_data;
380	max_brightness = led_cdev->max_brightness;
381	mode = lm3530_get_mode_from_str(buf);
382	if (mode < 0) {
383		dev_err(dev, "Invalid mode\n");
384		return mode;
385	}
386
387	drvdata->mode = mode;
388
389	/* set pwm to low if unnecessary */
390	if (mode != LM3530_BL_MODE_PWM && pwm->pwm_set_intensity)
391		pwm->pwm_set_intensity(0, max_brightness);
392
393	err = lm3530_init_registers(drvdata);
394	if (err) {
395		dev_err(dev, "Setting %s Mode failed :%d\n", buf, err);
396		return err;
397	}
398
399	return sizeof(drvdata->mode);
400}
401static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set);
402
403static struct attribute *lm3530_attrs[] = {
404	&dev_attr_mode.attr,
405	NULL
406};
407ATTRIBUTE_GROUPS(lm3530);
408
409static int lm3530_probe(struct i2c_client *client,
410			   const struct i2c_device_id *id)
411{
412	struct lm3530_platform_data *pdata = dev_get_platdata(&client->dev);
413	struct lm3530_data *drvdata;
414	int err = 0;
415
416	if (pdata == NULL) {
417		dev_err(&client->dev, "platform data required\n");
418		return -ENODEV;
419	}
420
421	/* BL mode */
422	if (pdata->mode > LM3530_BL_MODE_PWM) {
423		dev_err(&client->dev, "Illegal Mode request\n");
424		return -EINVAL;
425	}
426
427	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
428		dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
429		return -EIO;
430	}
431
432	drvdata = devm_kzalloc(&client->dev, sizeof(struct lm3530_data),
433				GFP_KERNEL);
434	if (drvdata == NULL)
435		return -ENOMEM;
436
437	drvdata->mode = pdata->mode;
438	drvdata->client = client;
439	drvdata->pdata = pdata;
440	drvdata->brightness = LED_OFF;
441	drvdata->enable = false;
442	drvdata->led_dev.name = LM3530_LED_DEV;
443	drvdata->led_dev.brightness_set = lm3530_brightness_set;
444	drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
445	drvdata->led_dev.groups = lm3530_groups;
446
447	i2c_set_clientdata(client, drvdata);
448
449	drvdata->regulator = devm_regulator_get(&client->dev, "vin");
450	if (IS_ERR(drvdata->regulator)) {
451		dev_err(&client->dev, "regulator get failed\n");
452		err = PTR_ERR(drvdata->regulator);
453		drvdata->regulator = NULL;
454		return err;
455	}
456
457	if (drvdata->pdata->brt_val) {
458		err = lm3530_init_registers(drvdata);
459		if (err < 0) {
460			dev_err(&client->dev,
461				"Register Init failed: %d\n", err);
462			return err;
463		}
464	}
465	err = led_classdev_register(&client->dev, &drvdata->led_dev);
466	if (err < 0) {
467		dev_err(&client->dev, "Register led class failed: %d\n", err);
468		return err;
469	}
470
471	return 0;
472}
473
474static int lm3530_remove(struct i2c_client *client)
475{
476	struct lm3530_data *drvdata = i2c_get_clientdata(client);
477
478	lm3530_led_disable(drvdata);
479	led_classdev_unregister(&drvdata->led_dev);
480	return 0;
481}
482
483static const struct i2c_device_id lm3530_id[] = {
484	{LM3530_NAME, 0},
485	{}
486};
487MODULE_DEVICE_TABLE(i2c, lm3530_id);
488
489static struct i2c_driver lm3530_i2c_driver = {
490	.probe = lm3530_probe,
491	.remove = lm3530_remove,
492	.id_table = lm3530_id,
493	.driver = {
494		.name = LM3530_NAME,
495	},
496};
497
498module_i2c_driver(lm3530_i2c_driver);
499
500MODULE_DESCRIPTION("Back Light driver for LM3530");
501MODULE_LICENSE("GPL v2");
502MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");
503