Root/drivers/leds/leds-lm3530.c

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 int lm3530_probe(struct i2c_client *client,
404               const struct i2c_device_id *id)
405{
406    struct lm3530_platform_data *pdata = client->dev.platform_data;
407    struct lm3530_data *drvdata;
408    int err = 0;
409
410    if (pdata == NULL) {
411        dev_err(&client->dev, "platform data required\n");
412        return -ENODEV;
413    }
414
415    /* BL mode */
416    if (pdata->mode > LM3530_BL_MODE_PWM) {
417        dev_err(&client->dev, "Illegal Mode request\n");
418        return -EINVAL;
419    }
420
421    if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
422        dev_err(&client->dev, "I2C_FUNC_I2C not supported\n");
423        return -EIO;
424    }
425
426    drvdata = devm_kzalloc(&client->dev, sizeof(struct lm3530_data),
427                GFP_KERNEL);
428    if (drvdata == NULL)
429        return -ENOMEM;
430
431    drvdata->mode = pdata->mode;
432    drvdata->client = client;
433    drvdata->pdata = pdata;
434    drvdata->brightness = LED_OFF;
435    drvdata->enable = false;
436    drvdata->led_dev.name = LM3530_LED_DEV;
437    drvdata->led_dev.brightness_set = lm3530_brightness_set;
438    drvdata->led_dev.max_brightness = MAX_BRIGHTNESS;
439
440    i2c_set_clientdata(client, drvdata);
441
442    drvdata->regulator = devm_regulator_get(&client->dev, "vin");
443    if (IS_ERR(drvdata->regulator)) {
444        dev_err(&client->dev, "regulator get failed\n");
445        err = PTR_ERR(drvdata->regulator);
446        drvdata->regulator = NULL;
447        return err;
448    }
449
450    if (drvdata->pdata->brt_val) {
451        err = lm3530_init_registers(drvdata);
452        if (err < 0) {
453            dev_err(&client->dev,
454                "Register Init failed: %d\n", err);
455            return err;
456        }
457    }
458    err = led_classdev_register(&client->dev, &drvdata->led_dev);
459    if (err < 0) {
460        dev_err(&client->dev, "Register led class failed: %d\n", err);
461        return err;
462    }
463
464    err = device_create_file(drvdata->led_dev.dev, &dev_attr_mode);
465    if (err < 0) {
466        dev_err(&client->dev, "File device creation failed: %d\n", err);
467        err = -ENODEV;
468        goto err_create_file;
469    }
470
471    return 0;
472
473err_create_file:
474    led_classdev_unregister(&drvdata->led_dev);
475    return err;
476}
477
478static int lm3530_remove(struct i2c_client *client)
479{
480    struct lm3530_data *drvdata = i2c_get_clientdata(client);
481
482    device_remove_file(drvdata->led_dev.dev, &dev_attr_mode);
483
484    lm3530_led_disable(drvdata);
485    led_classdev_unregister(&drvdata->led_dev);
486    return 0;
487}
488
489static const struct i2c_device_id lm3530_id[] = {
490    {LM3530_NAME, 0},
491    {}
492};
493MODULE_DEVICE_TABLE(i2c, lm3530_id);
494
495static struct i2c_driver lm3530_i2c_driver = {
496    .probe = lm3530_probe,
497    .remove = lm3530_remove,
498    .id_table = lm3530_id,
499    .driver = {
500        .name = LM3530_NAME,
501        .owner = THIS_MODULE,
502    },
503};
504
505module_i2c_driver(lm3530_i2c_driver);
506
507MODULE_DESCRIPTION("Back Light driver for LM3530");
508MODULE_LICENSE("GPL v2");
509MODULE_AUTHOR("Shreshtha Kumar SAHU <shreshthakumar.sahu@stericsson.com>");
510

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