leds-lm3530.c revision bbe6453204c568723679212f6d0653b92b3d6244 
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_ZONE_REG		0x40
30#define LM3530_ALS_IMP_SELECT		0x41
31#define LM3530_BRT_CTRL_REG		0xA0
32#define LM3530_ALS_ZB0_REG		0x60
33#define LM3530_ALS_ZB1_REG		0x61
34#define LM3530_ALS_ZB2_REG		0x62
35#define LM3530_ALS_ZB3_REG		0x63
36#define LM3530_ALS_Z0T_REG		0x70
37#define LM3530_ALS_Z1T_REG		0x71
38#define LM3530_ALS_Z2T_REG		0x72
39#define LM3530_ALS_Z3T_REG		0x73
40#define LM3530_ALS_Z4T_REG		0x74
41#define LM3530_REG_MAX			15
42
43/* General Control Register */
44#define LM3530_EN_I2C_SHIFT		(0)
45#define LM3530_RAMP_LAW_SHIFT		(1)
46#define LM3530_MAX_CURR_SHIFT		(2)
47#define LM3530_EN_PWM_SHIFT		(5)
48#define LM3530_PWM_POL_SHIFT		(6)
49#define LM3530_EN_PWM_SIMPLE_SHIFT	(7)
50
51#define LM3530_ENABLE_I2C		(1 << LM3530_EN_I2C_SHIFT)
52#define LM3530_ENABLE_PWM		(1 << LM3530_EN_PWM_SHIFT)
53#define LM3530_POL_LOW			(1 << LM3530_PWM_POL_SHIFT)
54#define LM3530_ENABLE_PWM_SIMPLE	(1 << LM3530_EN_PWM_SIMPLE_SHIFT)
55
56/* ALS Config Register Options */
57#define LM3530_ALS_AVG_TIME_SHIFT	(0)
58#define LM3530_EN_ALS_SHIFT		(3)
59#define LM3530_ALS_SEL_SHIFT		(5)
60
61#define LM3530_ENABLE_ALS		(3 << LM3530_EN_ALS_SHIFT)
62
63/* Brightness Ramp Rate Register */
64#define LM3530_BRT_RAMP_FALL_SHIFT	(0)
65#define LM3530_BRT_RAMP_RISE_SHIFT	(3)
66
67/* ALS Resistor Select */
68#define LM3530_ALS1_IMP_SHIFT		(0)
69#define LM3530_ALS2_IMP_SHIFT		(4)
70
71/* Zone Boundary Register defaults */
72#define LM3530_ALS_ZB_MAX		(4)
73#define LM3530_ALS_WINDOW_mV		(1000)
74#define LM3530_ALS_OFFSET_mV		(4)
75
76/* Zone Target Register defaults */
77#define LM3530_DEF_ZT_0			(0x7F)
78#define LM3530_DEF_ZT_1			(0x66)
79#define LM3530_DEF_ZT_2			(0x4C)
80#define LM3530_DEF_ZT_3			(0x33)
81#define LM3530_DEF_ZT_4			(0x19)
82
83/* 7 bits are used for the brightness : LM3530_BRT_CTRL_REG */
84#define MAX_BRIGHTNESS			(127)
85
86struct lm3530_mode_map {
87	const char *mode;
88	enum lm3530_mode mode_val;
89};
90
91static struct lm3530_mode_map mode_map[] = {
92	{ "man", LM3530_BL_MODE_MANUAL },
93	{ "als", LM3530_BL_MODE_ALS },
94	{ "pwm", LM3530_BL_MODE_PWM },
95};
96
97/**
98 * struct lm3530_data
99 * @led_dev: led class device
100 * @client: i2c client
101 * @pdata: LM3530 platform data
102 * @mode: mode of operation - manual, ALS, PWM
103 * @regulator: regulator
104 * @brighness: previous brightness value
105 * @enable: regulator is enabled
106 */
107struct lm3530_data {
108	struct led_classdev led_dev;
109	struct i2c_client *client;
110	struct lm3530_platform_data *pdata;
111	enum lm3530_mode mode;
112	struct regulator *regulator;
113	enum led_brightness brightness;
114	bool enable;
115};
116
117static const u8 lm3530_reg[LM3530_REG_MAX] = {
118	LM3530_GEN_CONFIG,
119	LM3530_ALS_CONFIG,
120	LM3530_BRT_RAMP_RATE,
121	LM3530_ALS_ZONE_REG,
122	LM3530_ALS_IMP_SELECT,
123	LM3530_BRT_CTRL_REG,
124	LM3530_ALS_ZB0_REG,
125	LM3530_ALS_ZB1_REG,
126	LM3530_ALS_ZB2_REG,
127	LM3530_ALS_ZB3_REG,
128	LM3530_ALS_Z0T_REG,
129	LM3530_ALS_Z1T_REG,
130	LM3530_ALS_Z2T_REG,
131	LM3530_ALS_Z3T_REG,
132	LM3530_ALS_Z4T_REG,
133};
134
135static int lm3530_get_mode_from_str(const char *str)
136{
137	int i;
138
139	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
140		if (sysfs_streq(str, mode_map[i].mode))
141			return mode_map[i].mode_val;
142
143	return -1;
144}
145
146static int lm3530_init_registers(struct lm3530_data *drvdata)
147{
148	int ret = 0;
149	int i;
150	u8 gen_config;
151	u8 als_config = 0;
152	u8 brt_ramp;
153	u8 als_imp_sel = 0;
154	u8 brightness;
155	u8 reg_val[LM3530_REG_MAX];
156	u8 zones[LM3530_ALS_ZB_MAX];
157	u32 als_vmin, als_vmax, als_vstep;
158	struct lm3530_platform_data *pltfm = drvdata->pdata;
159	struct i2c_client *client = drvdata->client;
160
161	gen_config = (pltfm->brt_ramp_law << LM3530_RAMP_LAW_SHIFT) |
162			((pltfm->max_current & 7) << LM3530_MAX_CURR_SHIFT);
163
164	if (drvdata->mode == LM3530_BL_MODE_MANUAL ||
165	    drvdata->mode == LM3530_BL_MODE_ALS)
166		gen_config |= (LM3530_ENABLE_I2C);
167
168	if (drvdata->mode == LM3530_BL_MODE_ALS) {
169		if (pltfm->als_vmax == 0) {
170			pltfm->als_vmin = 0;
171			pltfm->als_vmax = LM3530_ALS_WINDOW_mV;
172		}
173
174		als_vmin = pltfm->als_vmin;
175		als_vmax = pltfm->als_vmax;
176
177		if ((als_vmax - als_vmin) > LM3530_ALS_WINDOW_mV)
178			pltfm->als_vmax = als_vmax =
179				als_vmin + LM3530_ALS_WINDOW_mV;
180
181		/* n zone boundary makes n+1 zones */
182		als_vstep = (als_vmax - als_vmin) / (LM3530_ALS_ZB_MAX + 1);
183
184		for (i = 0; i < LM3530_ALS_ZB_MAX; i++)
185			zones[i] = (((als_vmin + LM3530_ALS_OFFSET_mV) +
186					als_vstep + (i * als_vstep)) * LED_FULL)
187					/ 1000;
188
189		als_config =
190			(pltfm->als_avrg_time << LM3530_ALS_AVG_TIME_SHIFT) |
191			(LM3530_ENABLE_ALS) |
192			(pltfm->als_input_mode << LM3530_ALS_SEL_SHIFT);
193
194		als_imp_sel =
195			(pltfm->als1_resistor_sel << LM3530_ALS1_IMP_SHIFT) |
196			(pltfm->als2_resistor_sel << LM3530_ALS2_IMP_SHIFT);
197
198	}
199
200	if (drvdata->mode == LM3530_BL_MODE_PWM)
201		gen_config |= (LM3530_ENABLE_PWM) |
202				(pltfm->pwm_pol_hi << LM3530_PWM_POL_SHIFT) |
203				(LM3530_ENABLE_PWM_SIMPLE);
204
205	brt_ramp = (pltfm->brt_ramp_fall << LM3530_BRT_RAMP_FALL_SHIFT) |
206			(pltfm->brt_ramp_rise << LM3530_BRT_RAMP_RISE_SHIFT);
207
208	if (drvdata->brightness)
209		brightness = drvdata->brightness;
210	else
211		brightness = drvdata->brightness = pltfm->brt_val;
212
213	if (brightness > drvdata->led_dev.max_brightness)
214		brightness = drvdata->led_dev.max_brightness;
215
216	reg_val[0] = gen_config;	/* LM3530_GEN_CONFIG */
217	reg_val[1] = als_config;	/* LM3530_ALS_CONFIG */
218	reg_val[2] = brt_ramp;		/* LM3530_BRT_RAMP_RATE */
219	reg_val[3] = 0x00;		/* LM3530_ALS_ZONE_REG */
220	reg_val[4] = als_imp_sel;	/* LM3530_ALS_IMP_SELECT */
221	reg_val[5] = brightness;	/* LM3530_BRT_CTRL_REG */
222	reg_val[6] = zones[0];		/* LM3530_ALS_ZB0_REG */
223	reg_val[7] = zones[1];		/* LM3530_ALS_ZB1_REG */
224	reg_val[8] = zones[2];		/* LM3530_ALS_ZB2_REG */
225	reg_val[9] = zones[3];		/* LM3530_ALS_ZB3_REG */
226	reg_val[10] = LM3530_DEF_ZT_0;	/* LM3530_ALS_Z0T_REG */
227	reg_val[11] = LM3530_DEF_ZT_1;	/* LM3530_ALS_Z1T_REG */
228	reg_val[12] = LM3530_DEF_ZT_2;	/* LM3530_ALS_Z2T_REG */
229	reg_val[13] = LM3530_DEF_ZT_3;	/* LM3530_ALS_Z3T_REG */
230	reg_val[14] = 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		ret = i2c_smbus_write_byte_data(client,
244				lm3530_reg[i], reg_val[i]);
245		if (ret)
246			break;
247	}
248
249	return ret;
250}
251
252static void lm3530_brightness_set(struct led_classdev *led_cdev,
253				     enum led_brightness brt_val)
254{
255	int err;
256	struct lm3530_data *drvdata =
257	    container_of(led_cdev, struct lm3530_data, led_dev);
258
259	switch (drvdata->mode) {
260	case LM3530_BL_MODE_MANUAL:
261
262		if (!drvdata->enable) {
263			err = lm3530_init_registers(drvdata);
264			if (err) {
265				dev_err(&drvdata->client->dev,
266					"Register Init failed: %d\n", err);
267				break;
268			}
269		}
270
271		/* set the brightness in brightness control register*/
272		err = i2c_smbus_write_byte_data(drvdata->client,
273				LM3530_BRT_CTRL_REG, brt_val);
274		if (err)
275			dev_err(&drvdata->client->dev,
276				"Unable to set brightness: %d\n", err);
277		else
278			drvdata->brightness = brt_val;
279
280		if (brt_val == 0) {
281			err = regulator_disable(drvdata->regulator);
282			if (err)
283				dev_err(&drvdata->client->dev,
284					"Disable regulator failed\n");
285			drvdata->enable = false;
286		}
287		break;
288	case LM3530_BL_MODE_ALS:
289		break;
290	case LM3530_BL_MODE_PWM:
291		break;
292	default:
293		break;
294	}
295}
296
297static ssize_t lm3530_mode_get(struct device *dev,
298		struct device_attribute *attr, char *buf)
299{
300	struct i2c_client *client = container_of(
301					dev->parent, struct i2c_client, dev);
302	struct lm3530_data *drvdata = i2c_get_clientdata(client);
303	int i, len = 0;
304
305	for (i = 0; i < ARRAY_SIZE(mode_map); i++)
306		if (drvdata->mode == mode_map[i].mode_val)
307			len += sprintf(buf + len, "[%s] ", mode_map[i].mode);
308		else
309			len += sprintf(buf + len, "%s ", mode_map[i].mode);
310
311	len += sprintf(buf + len, "\n");
312
313	return len;
314}
315
316static ssize_t lm3530_mode_set(struct device *dev, struct device_attribute
317				   *attr, const char *buf, size_t size)
318{
319	int err;
320	struct i2c_client *client = container_of(
321					dev->parent, struct i2c_client, dev);
322	struct lm3530_data *drvdata = i2c_get_clientdata(client);
323	int mode;
324
325	mode = lm3530_get_mode_from_str(buf);
326	if (mode < 0) {
327		dev_err(dev, "Invalid mode\n");
328		return -EINVAL;
329	}
330
331	if (mode == LM3530_BL_MODE_MANUAL)
332		drvdata->mode = LM3530_BL_MODE_MANUAL;
333	else if (mode == LM3530_BL_MODE_ALS)
334		drvdata->mode = LM3530_BL_MODE_ALS;
335	else if (mode == LM3530_BL_MODE_PWM) {
336		dev_err(dev, "PWM mode not supported\n");
337		return -EINVAL;
338	}
339
340	err = lm3530_init_registers(drvdata);
341	if (err) {
342		dev_err(dev, "Setting %s Mode failed :%d\n", buf, err);
343		return err;
344	}
345
346	return sizeof(drvdata->mode);
347}
348static DEVICE_ATTR(mode, 0644, lm3530_mode_get, lm3530_mode_set);
349
350static int __devinit lm3530_probe(struct i2c_client *client,
351			   const struct i2c_device_id *id)
352{
353	struct lm3530_platform_data *pdata = client->dev.platform_data;
354	struct lm3530_data *drvdata;
355	int err = 0;
356
357	if (pdata == NULL) {
358		dev_err(&client->dev, "platform data required\n");
359		err = -ENODEV;
360		goto err_out;
361	}
362
363	/* BL mode */
364	if (pdata->mode > LM3530_BL_MODE_PWM) {
365		dev_err(&client->dev, "Illegal Mode request\n");
366		err = -EINVAL;
367		goto err_out;
368	}
369
370	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
371		dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
372		err = -EIO;
373		goto err_out;
374	}
375
376	drvdata = kzalloc(sizeof(struct lm3530_data), GFP_KERNEL);
377	if (drvdata == NULL) {
378		err = -ENOMEM;
379		goto err_out;
380	}
381
382	drvdata->mode = pdata->mode;
383	drvdata->client = client;
384	drvdata->pdata = pdata;
385	drvdata->brightness = LED_OFF;
386	drvdata->enable = false;
387	drvdata->led_dev.name = LM3530_LED_DEV;
388	drvdata->led_dev.brightness_set = lm3530_brightness_set;
389	drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
390
391	i2c_set_clientdata(client, drvdata);
392
393	drvdata->regulator = regulator_get(&client->dev, "vin");
394	if (IS_ERR(drvdata->regulator)) {
395		dev_err(&client->dev, "regulator get failed\n");
396		err = PTR_ERR(drvdata->regulator);
397		drvdata->regulator = NULL;
398		goto err_regulator_get;
399	}
400
401	if (drvdata->pdata->brt_val) {
402		err = lm3530_init_registers(drvdata);
403		if (err < 0) {
404			dev_err(&client->dev,
405				"Register Init failed: %d\n", err);
406			err = -ENODEV;
407			goto err_reg_init;
408		}
409	}
410	err = led_classdev_register(&client->dev, &drvdata->led_dev);
411	if (err < 0) {
412		dev_err(&client->dev, "Register led class failed: %d\n", err);
413		err = -ENODEV;
414		goto err_class_register;
415	}
416
417	err = device_create_file(drvdata->led_dev.dev, &dev_attr_mode);
418	if (err < 0) {
419		dev_err(&client->dev, "File device creation failed: %d\n", err);
420		err = -ENODEV;
421		goto err_create_file;
422	}
423
424	return 0;
425
426err_create_file:
427	led_classdev_unregister(&drvdata->led_dev);
428err_class_register:
429err_reg_init:
430	regulator_put(drvdata->regulator);
431err_regulator_get:
432	kfree(drvdata);
433err_out:
434	return err;
435}
436
437static int __devexit lm3530_remove(struct i2c_client *client)
438{
439	struct lm3530_data *drvdata = i2c_get_clientdata(client);
440
441	device_remove_file(drvdata->led_dev.dev, &dev_attr_mode);
442
443	if (drvdata->enable)
444		regulator_disable(drvdata->regulator);
445	regulator_put(drvdata->regulator);
446	led_classdev_unregister(&drvdata->led_dev);
447	kfree(drvdata);
448	return 0;
449}
450
451static const struct i2c_device_id lm3530_id[] = {
452	{LM3530_NAME, 0},
453	{}
454};
455MODULE_DEVICE_TABLE(i2c, lm3530_id);
456
457static struct i2c_driver lm3530_i2c_driver = {
458	.probe = lm3530_probe,
459	.remove = __devexit_p(lm3530_remove),
460	.id_table = lm3530_id,
461	.driver = {
462		.name = LM3530_NAME,
463		.owner = THIS_MODULE,
464	},
465};
466
467module_i2c_driver(lm3530_i2c_driver);
468
469MODULE_DESCRIPTION("Back Light driver for LM3530");
470MODULE_LICENSE("GPL v2");
471MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");
472