leds-lm3530.c revision 99ad98d25961487d83ac4afac0375fe1f3e5c883 
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	if (drvdata->mode == LM3530_BL_MODE_MANUAL ||
164	    drvdata->mode == LM3530_BL_MODE_ALS)
165		gen_config |= (LM3530_ENABLE_I2C);
166
167	if (drvdata->mode == LM3530_BL_MODE_ALS) {
168		if (pdata->als_vmax == 0) {
169			pdata->als_vmin = 0;
170			pdata->als_vmax = LM3530_ALS_WINDOW_mV;
171		}
172
173		als_vmin = pdata->als_vmin;
174		als_vmax = pdata->als_vmax;
175
176		if ((als_vmax - als_vmin) > LM3530_ALS_WINDOW_mV)
177			pdata->als_vmax = als_vmax =
178				als_vmin + LM3530_ALS_WINDOW_mV;
179
180		/* n zone boundary makes n+1 zones */
181		als_vstep = (als_vmax - als_vmin) / (LM3530_ALS_ZB_MAX + 1);
182
183		for (i = 0; i < LM3530_ALS_ZB_MAX; i++)
184			zones[i] = (((als_vmin + LM3530_ALS_OFFSET_mV) +
185					als_vstep + (i * als_vstep)) * LED_FULL)
186					/ 1000;
187
188		als_config =
189			(pdata->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) |
190			(LM3530_ENABLE_ALS) |
191			(pdata->als_input_mode << LM3530_ALS_SEL_SHIFT);
192
193		als_imp_sel =
194			(pdata->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) |
195			(pdata->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT);
196
197	}
198
199	if (drvdata->mode == LM3530_BL_MODE_PWM)
200		gen_config |= (LM3530_ENABLE_PWM) |
201				(pdata->pwm_pol_hi << LM3530_PWM_POL_SHIFT) |
202				(LM3530_ENABLE_PWM_SIMPLE);
203
204	brt_ramp = (pdata->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) |
205			(pdata->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT);
206
207	if (drvdata->brightness)
208		brightness = drvdata->brightness;
209	else
210		brightness = drvdata->brightness = pdata->brt_val;
211
212	if (brightness > drvdata->led_dev.max_brightness)
213		brightness = drvdata->led_dev.max_brightness;
214
215	reg_val[0] = gen_config;	/* LM3530_GEN_CONFIG */
216	reg_val[1] = als_config;	/* LM3530_ALS_CONFIG */
217	reg_val[2] = brt_ramp;		/* LM3530_BRT_RAMP_RATE */
218	reg_val[3] = als_imp_sel;	/* LM3530_ALS_IMP_SELECT */
219	reg_val[4] = brightness;	/* LM3530_BRT_CTRL_REG */
220	reg_val[5] = zones[0];		/* LM3530_ALS_ZB0_REG */
221	reg_val[6] = zones[1];		/* LM3530_ALS_ZB1_REG */
222	reg_val[7] = zones[2];		/* LM3530_ALS_ZB2_REG */
223	reg_val[8] = zones[3];		/* LM3530_ALS_ZB3_REG */
224	reg_val[9] = LM3530_DEF_ZT_0;	/* LM3530_ALS_Z0T_REG */
225	reg_val[10] = LM3530_DEF_ZT_1;	/* LM3530_ALS_Z1T_REG */
226	reg_val[11] = LM3530_DEF_ZT_2;	/* LM3530_ALS_Z2T_REG */
227	reg_val[12] = LM3530_DEF_ZT_3;	/* LM3530_ALS_Z3T_REG */
228	reg_val[13] = LM3530_DEF_ZT_4;	/* LM3530_ALS_Z4T_REG */
229
230	if (!drvdata->enable) {
231		ret = regulator_enable(drvdata->regulator);
232		if (ret) {
233			dev_err(&drvdata->client->dev,
234					"Enable regulator failed\n");
235			return ret;
236		}
237		drvdata->enable = true;
238	}
239
240	for (i = 0; i < LM3530_REG_MAX; i++) {
241		/* do not update brightness register when pwm mode */
242		if (lm3530_reg[i] == LM3530_BRT_CTRL_REG &&
243		    drvdata->mode == LM3530_BL_MODE_PWM) {
244			if (pwm->pwm_set_intensity)
245				pwm->pwm_set_intensity(reg_val[i],
246					drvdata->led_dev.max_brightness);
247			continue;
248		}
249
250		ret = i2c_smbus_write_byte_data(client,
251				lm3530_reg[i], reg_val[i]);
252		if (ret)
253			break;
254	}
255
256	return ret;
257}
258
259static void lm3530_brightness_set(struct led_classdev *led_cdev,
260				     enum led_brightness brt_val)
261{
262	int err;
263	struct lm3530_data *drvdata =
264	    container_of(led_cdev, struct lm3530_data, led_dev);
265	struct lm3530_platform_data *pdata = drvdata->pdata;
266	struct lm3530_pwm_data *pwm = &pdata->pwm_data;
267	u8 max_brightness = led_cdev->max_brightness;
268
269	switch (drvdata->mode) {
270	case LM3530_BL_MODE_MANUAL:
271
272		if (!drvdata->enable) {
273			err = lm3530_init_registers(drvdata);
274			if (err) {
275				dev_err(&drvdata->client->dev,
276					"Register Init failed: %d\n", err);
277				break;
278			}
279		}
280
281		/* set the brightness in brightness control register*/
282		err = i2c_smbus_write_byte_data(drvdata->client,
283				LM3530_BRT_CTRL_REG, brt_val);
284		if (err)
285			dev_err(&drvdata->client->dev,
286				"Unable to set brightness: %d\n", err);
287		else
288			drvdata->brightness = brt_val;
289
290		if (brt_val == 0) {
291			err = regulator_disable(drvdata->regulator);
292			if (err)
293				dev_err(&drvdata->client->dev,
294					"Disable regulator failed\n");
295			drvdata->enable = false;
296		}
297		break;
298	case LM3530_BL_MODE_ALS:
299		break;
300	case LM3530_BL_MODE_PWM:
301		if (pwm->pwm_set_intensity)
302			pwm->pwm_set_intensity(brt_val, max_brightness);
303		break;
304	default:
305		break;
306	}
307}
308
309static ssize_t lm3530_mode_get(struct device *dev,
310		struct device_attribute *attr, char *buf)
311{
312	struct led_classdev *led_cdev = dev_get_drvdata(dev);
313	struct lm3530_data *drvdata;
314	int i, len = 0;
315
316	drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
317	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
318		if (drvdata->mode == mode_map[i].mode_val)
319			len += sprintf(buf + len, "[%s] ", mode_map[i].mode);
320		else
321			len += sprintf(buf + len, "%s ", mode_map[i].mode);
322
323	len += sprintf(buf + len, "\n");
324
325	return len;
326}
327
328static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
329				   *attr, const char *buf, size_t size)
330{
331	struct led_classdev *led_cdev = dev_get_drvdata(dev);
332	struct lm3530_data *drvdata;
333	struct lm3530_pwm_data *pwm;
334	u8 max_brightness;
335	int mode, err;
336
337	drvdata = container_of(led_cdev, struct lm3530_data, led_dev);
338	pwm = &drvdata->pdata->pwm_data;
339	max_brightness = led_cdev->max_brightness;
340	mode = lm3530_get_mode_from_str(buf);
341	if (mode < 0) {
342		dev_err(dev, "Invalid mode\n");
343		return -EINVAL;
344	}
345
346	drvdata->mode = mode;
347
348	/* set pwm to low if unnecessary */
349	if (mode != LM3530_BL_MODE_PWM && pwm->pwm_set_intensity)
350		pwm->pwm_set_intensity(0, max_brightness);
351
352	err = lm3530_init_registers(drvdata);
353	if (err) {
354		dev_err(dev, "Setting %s Mode failed :%d\n", buf, err);
355		return err;
356	}
357
358	return sizeof(drvdata->mode);
359}
360static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set);
361
362static int __devinit lm3530_probe(struct i2c_client *client,
363			   const struct i2c_device_id *id)
364{
365	struct lm3530_platform_data *pdata = client->dev.platform_data;
366	struct lm3530_data *drvdata;
367	int err = 0;
368
369	if (pdata == NULL) {
370		dev_err(&client->dev, "platform data required\n");
371		err = -ENODEV;
372		goto err_out;
373	}
374
375	/* BL mode */
376	if (pdata->mode > LM3530_BL_MODE_PWM) {
377		dev_err(&client->dev, "Illegal Mode request\n");
378		err = -EINVAL;
379		goto err_out;
380	}
381
382	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
383		dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
384		err = -EIO;
385		goto err_out;
386	}
387
388	drvdata = kzalloc(sizeof(struct lm3530_data), GFP_KERNEL);
389	if (drvdata == NULL) {
390		err = -ENOMEM;
391		goto err_out;
392	}
393
394	drvdata->mode = pdata->mode;
395	drvdata->client = client;
396	drvdata->pdata = pdata;
397	drvdata->brightness = LED_OFF;
398	drvdata->enable = false;
399	drvdata->led_dev.name = LM3530_LED_DEV;
400	drvdata->led_dev.brightness_set = lm3530_brightness_set;
401	drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
402
403	i2c_set_clientdata(client, drvdata);
404
405	drvdata->regulator = regulator_get(&client->dev, "vin");
406	if (IS_ERR(drvdata->regulator)) {
407		dev_err(&client->dev, "regulator get failed\n");
408		err = PTR_ERR(drvdata->regulator);
409		drvdata->regulator = NULL;
410		goto err_regulator_get;
411	}
412
413	if (drvdata->pdata->brt_val) {
414		err = lm3530_init_registers(drvdata);
415		if (err < 0) {
416			dev_err(&client->dev,
417				"Register Init failed: %d\n", err);
418			err = -ENODEV;
419			goto err_reg_init;
420		}
421	}
422	err = led_classdev_register(&client->dev, &drvdata->led_dev);
423	if (err < 0) {
424		dev_err(&client->dev, "Register led class failed: %d\n", err);
425		err = -ENODEV;
426		goto err_class_register;
427	}
428
429	err = device_create_file(drvdata->led_dev.dev, &dev_attr_mode);
430	if (err < 0) {
431		dev_err(&client->dev, "File device creation failed: %d\n", err);
432		err = -ENODEV;
433		goto err_create_file;
434	}
435
436	return 0;
437
438err_create_file:
439	led_classdev_unregister(&drvdata->led_dev);
440err_class_register:
441err_reg_init:
442	regulator_put(drvdata->regulator);
443err_regulator_get:
444	kfree(drvdata);
445err_out:
446	return err;
447}
448
449static int __devexit lm3530_remove(struct i2c_client *client)
450{
451	struct lm3530_data *drvdata = i2c_get_clientdata(client);
452
453	device_remove_file(drvdata->led_dev.dev, &dev_attr_mode);
454
455	if (drvdata->enable)
456		regulator_disable(drvdata->regulator);
457	regulator_put(drvdata->regulator);
458	led_classdev_unregister(&drvdata->led_dev);
459	kfree(drvdata);
460	return 0;
461}
462
463static const struct i2c_device_id lm3530_id[] = {
464	{LM3530_NAME, 0},
465	{}
466};
467MODULE_DEVICE_TABLE(i2c, lm3530_id);
468
469static struct i2c_driver lm3530_i2c_driver = {
470	.probe = lm3530_probe,
471	.remove = __devexit_p(lm3530_remove),
472	.id_table = lm3530_id,
473	.driver = {
474		.name = LM3530_NAME,
475		.owner = THIS_MODULE,
476	},
477};
478
479module_i2c_driver(lm3530_i2c_driver);
480
481MODULE_DESCRIPTION("Back Light driver for LM3530");
482MODULE_LICENSE("GPL v2");
483MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");
484