leds-lm3530.c revision cea694ca3d0894ee97482be1f22b822dc948c66f 
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
116static const u8 lm3530_reg[LM3530_REG_MAX] = {
117	LM3530_GEN_CONFIG,
118	LM3530_ALS_CONFIG,
119	LM3530_BRT_RAMP_RATE,
120	LM3530_ALS_IMP_SELECT,
121	LM3530_BRT_CTRL_REG,
122	LM3530_ALS_ZB0_REG,
123	LM3530_ALS_ZB1_REG,
124	LM3530_ALS_ZB2_REG,
125	LM3530_ALS_ZB3_REG,
126	LM3530_ALS_Z0T_REG,
127	LM3530_ALS_Z1T_REG,
128	LM3530_ALS_Z2T_REG,
129	LM3530_ALS_Z3T_REG,
130	LM3530_ALS_Z4T_REG,
131};
132
133static int lm3530_get_mode_from_str(const char *str)
134{
135	int i;
136
137	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
138		if (sysfs_streq(str, mode_map[i].mode))
139			return mode_map[i].mode_val;
140
141	return -1;
142}
143
144static int lm3530_init_registers(struct lm3530_data *drvdata)
145{
146	int ret = 0;
147	int i;
148	u8 gen_config;
149	u8 als_config = 0;
150	u8 brt_ramp;
151	u8 als_imp_sel = 0;
152	u8 brightness;
153	u8 reg_val[LM3530_REG_MAX];
154	u8 zones[LM3530_ALS_ZB_MAX];
155	u32 als_vmin, als_vmax, als_vstep;
156	struct lm3530_platform_data *pdata = drvdata->pdata;
157	struct i2c_client *client = drvdata->client;
158	struct lm3530_pwm_data *pwm = &pdata->pwm_data;
159
160	gen_config = (pdata->brt_ramp_law << LM3530_RAMP_LAW_SHIFT) |
161			((pdata->max_current & 7) << LM3530_MAX_CURR_SHIFT);
162
163	switch (drvdata->mode) {
164	case LM3530_BL_MODE_MANUAL:
165	case LM3530_BL_MODE_ALS:
166		gen_config |= LM3530_ENABLE_I2C;
167		break;
168	case LM3530_BL_MODE_PWM:
169		gen_config |= LM3530_ENABLE_PWM | LM3530_ENABLE_PWM_SIMPLE |
170			      (pdata->pwm_pol_hi << LM3530_PWM_POL_SHIFT);
171		break;
172	}
173
174	if (drvdata->mode == LM3530_BL_MODE_ALS) {
175		if (pdata->als_vmax == 0) {
176			pdata->als_vmin = 0;
177			pdata->als_vmax = LM3530_ALS_WINDOW_mV;
178		}
179
180		als_vmin = pdata->als_vmin;
181		als_vmax = pdata->als_vmax;
182
183		if ((als_vmax - als_vmin) > LM3530_ALS_WINDOW_mV)
184			pdata->als_vmax = als_vmax =
185				als_vmin + LM3530_ALS_WINDOW_mV;
186
187		/* n zone boundary makes n+1 zones */
188		als_vstep = (als_vmax - als_vmin) / (LM3530_ALS_ZB_MAX + 1);
189
190		for (i = 0; i < LM3530_ALS_ZB_MAX; i++)
191			zones[i] = (((als_vmin + LM3530_ALS_OFFSET_mV) +
192					als_vstep + (i * als_vstep)) * LED_FULL)
193					/ 1000;
194
195		als_config =
196			(pdata->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) |
197			(LM3530_ENABLE_ALS) |
198			(pdata->als_input_mode << LM3530_ALS_SEL_SHIFT);
199
200		als_imp_sel =
201			(pdata->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) |
202			(pdata->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT);
203
204	}
205
206	brt_ramp = (pdata->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) |
207			(pdata->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT);
208
209	if (drvdata->brightness)
210		brightness = drvdata->brightness;
211	else
212		brightness = drvdata->brightness = pdata->brt_val;
213
214	if (brightness > drvdata->led_dev.max_brightness)
215		brightness = drvdata->led_dev.max_brightness;
216
217	reg_val[0] = gen_config;	/* LM3530_GEN_CONFIG */
218	reg_val[1] = als_config;	/* LM3530_ALS_CONFIG */
219	reg_val[2] = brt_ramp;		/* LM3530_BRT_RAMP_RATE */
220	reg_val[3] = als_imp_sel;	/* LM3530_ALS_IMP_SELECT */
221	reg_val[4] = brightness;	/* LM3530_BRT_CTRL_REG */
222	reg_val[5] = zones[0];		/* LM3530_ALS_ZB0_REG */
223	reg_val[6] = zones[1];		/* LM3530_ALS_ZB1_REG */
224	reg_val[7] = zones[2];		/* LM3530_ALS_ZB2_REG */
225	reg_val[8] = zones[3];		/* LM3530_ALS_ZB3_REG */
226	reg_val[9] = LM3530_DEF_ZT_0;	/* LM3530_ALS_Z0T_REG */
227	reg_val[10] = LM3530_DEF_ZT_1;	/* LM3530_ALS_Z1T_REG */
228	reg_val[11] = LM3530_DEF_ZT_2;	/* LM3530_ALS_Z2T_REG */
229	reg_val[12] = LM3530_DEF_ZT_3;	/* LM3530_ALS_Z3T_REG */
230	reg_val[13] = LM3530_DEF_ZT_4;	/* LM3530_ALS_Z4T_REG */
231
232	if (!drvdata->enable) {
233		ret = regulator_enable(drvdata->regulator);
234		if (ret) {
235			dev_err(&drvdata->client->dev,
236					"Enable regulator failed\n");
237			return ret;
238		}
239		drvdata->enable = true;
240	}
241
242	for (i = 0; i < LM3530_REG_MAX; i++) {
243		/* do not update brightness register when pwm mode */
244		if (lm3530_reg[i] == LM3530_BRT_CTRL_REG &&
245		    drvdata->mode == LM3530_BL_MODE_PWM) {
246			if (pwm->pwm_set_intensity)
247				pwm->pwm_set_intensity(reg_val[i],
248					drvdata->led_dev.max_brightness);
249			continue;
250		}
251
252		ret = i2c_smbus_write_byte_data(client,
253				lm3530_reg[i], reg_val[i]);
254		if (ret)
255			break;
256	}
257
258	return ret;
259}
260
261static void lm3530_brightness_set(struct led_classdev *led_cdev,
262				     enum led_brightness brt_val)
263{
264	int err;
265	struct lm3530_data *drvdata =
266	    container_of(led_cdev, struct lm3530_data, led_dev);
267	struct lm3530_platform_data *pdata = drvdata->pdata;
268	struct lm3530_pwm_data *pwm = &pdata->pwm_data;
269	u8 max_brightness = led_cdev->max_brightness;
270
271	switch (drvdata->mode) {
272	case LM3530_BL_MODE_MANUAL:
273
274		if (!drvdata->enable) {
275			err = lm3530_init_registers(drvdata);
276			if (err) {
277				dev_err(&drvdata->client->dev,
278					"Register Init failed: %d\n", err);
279				break;
280			}
281		}
282
283		/* set the brightness in brightness control register*/
284		err = i2c_smbus_write_byte_data(drvdata->client,
285				LM3530_BRT_CTRL_REG, brt_val);
286		if (err)
287			dev_err(&drvdata->client->dev,
288				"Unable to set brightness: %d\n", err);
289		else
290			drvdata->brightness = brt_val;
291
292		if (brt_val == 0) {
293			err = regulator_disable(drvdata->regulator);
294			if (err)
295				dev_err(&drvdata->client->dev,
296					"Disable regulator failed\n");
297			drvdata->enable = false;
298		}
299		break;
300	case LM3530_BL_MODE_ALS:
301		break;
302	case LM3530_BL_MODE_PWM:
303		if (pwm->pwm_set_intensity)
304			pwm->pwm_set_intensity(brt_val, max_brightness);
305		break;
306	default:
307		break;
308	}
309}
310
311static ssize_t lm3530_mode_get(struct device *dev,
312		struct device_attribute *attr, char *buf)
313{
314	struct led_classdev *led_cdev = dev_get_drvdata(dev);
315	struct lm3530_data *drvdata;
316	int i, len = 0;
317
318	drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
319	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
320		if (drvdata->mode == mode_map[i].mode_val)
321			len += sprintf(buf + len, "[%s] ", mode_map[i].mode);
322		else
323			len += sprintf(buf + len, "%s ", mode_map[i].mode);
324
325	len += sprintf(buf + len, "\n");
326
327	return len;
328}
329
330static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
331				   *attr, const char *buf, size_t size)
332{
333	struct led_classdev *led_cdev = dev_get_drvdata(dev);
334	struct lm3530_data *drvdata;
335	struct lm3530_pwm_data *pwm;
336	u8 max_brightness;
337	int mode, err;
338
339	drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
340	pwm = &drvdata->pdata->pwm_data;
341	max_brightness = led_cdev->max_brightness;
342	mode = lm3530_get_mode_from_str(buf);
343	if (mode < 0) {
344		dev_err(dev, "Invalid mode\n");
345		return -EINVAL;
346	}
347
348	drvdata->mode = mode;
349
350	/* set pwm to low if unnecessary */
351	if (mode != LM3530_BL_MODE_PWM && pwm->pwm_set_intensity)
352		pwm->pwm_set_intensity(0, max_brightness);
353
354	err = lm3530_init_registers(drvdata);
355	if (err) {
356		dev_err(dev, "Setting %s Mode failed :%d\n", buf, err);
357		return err;
358	}
359
360	return sizeof(drvdata->mode);
361}
362static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set);
363
364static int __devinit lm3530_probe(struct i2c_client *client,
365			   const struct i2c_device_id *id)
366{
367	struct lm3530_platform_data *pdata = client->dev.platform_data;
368	struct lm3530_data *drvdata;
369	int err = 0;
370
371	if (pdata == NULL) {
372		dev_err(&client->dev, "platform data required\n");
373		err = -ENODEV;
374		goto err_out;
375	}
376
377	/* BL mode */
378	if (pdata->mode > LM3530_BL_MODE_PWM) {
379		dev_err(&client->dev, "Illegal Mode request\n");
380		err = -EINVAL;
381		goto err_out;
382	}
383
384	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
385		dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
386		err = -EIO;
387		goto err_out;
388	}
389
390	drvdata = kzalloc(sizeof(struct lm3530_data), GFP_KERNEL);
391	if (drvdata == NULL) {
392		err = -ENOMEM;
393		goto err_out;
394	}
395
396	drvdata->mode = pdata->mode;
397	drvdata->client = client;
398	drvdata->pdata = pdata;
399	drvdata->brightness = LED_OFF;
400	drvdata->enable = false;
401	drvdata->led_dev.name = LM3530_LED_DEV;
402	drvdata->led_dev.brightness_set = lm3530_brightness_set;
403	drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
404
405	i2c_set_clientdata(client, drvdata);
406
407	drvdata->regulator = regulator_get(&client->dev, "vin");
408	if (IS_ERR(drvdata->regulator)) {
409		dev_err(&client->dev, "regulator get failed\n");
410		err = PTR_ERR(drvdata->regulator);
411		drvdata->regulator = NULL;
412		goto err_regulator_get;
413	}
414
415	if (drvdata->pdata->brt_val) {
416		err = lm3530_init_registers(drvdata);
417		if (err < 0) {
418			dev_err(&client->dev,
419				"Register Init failed: %d\n", err);
420			err = -ENODEV;
421			goto err_reg_init;
422		}
423	}
424	err = led_classdev_register(&client->dev, &drvdata->led_dev);
425	if (err < 0) {
426		dev_err(&client->dev, "Register led class failed: %d\n", err);
427		err = -ENODEV;
428		goto err_class_register;
429	}
430
431	err = device_create_file(drvdata->led_dev.dev, &dev_attr_mode);
432	if (err < 0) {
433		dev_err(&client->dev, "File device creation failed: %d\n", err);
434		err = -ENODEV;
435		goto err_create_file;
436	}
437
438	return 0;
439
440err_create_file:
441	led_classdev_unregister(&drvdata->led_dev);
442err_class_register:
443err_reg_init:
444	regulator_put(drvdata->regulator);
445err_regulator_get:
446	kfree(drvdata);
447err_out:
448	return err;
449}
450
451static int __devexit lm3530_remove(struct i2c_client *client)
452{
453	struct lm3530_data *drvdata = i2c_get_clientdata(client);
454
455	device_remove_file(drvdata->led_dev.dev, &dev_attr_mode);
456
457	if (drvdata->enable)
458		regulator_disable(drvdata->regulator);
459	regulator_put(drvdata->regulator);
460	led_classdev_unregister(&drvdata->led_dev);
461	kfree(drvdata);
462	return 0;
463}
464
465static const struct i2c_device_id lm3530_id[] = {
466	{LM3530_NAME, 0},
467	{}
468};
469MODULE_DEVICE_TABLE(i2c, lm3530_id);
470
471static struct i2c_driver lm3530_i2c_driver = {
472	.probe = lm3530_probe,
473	.remove = __devexit_p(lm3530_remove),
474	.id_table = lm3530_id,
475	.driver = {
476		.name = LM3530_NAME,
477		.owner = THIS_MODULE,
478	},
479};
480
481module_i2c_driver(lm3530_i2c_driver);
482
483MODULE_DESCRIPTION("Back Light driver for LM3530");
484MODULE_LICENSE("GPL v2");
485MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");
486