LP8758 - consolidated version
[mlp-open-source/kernel.git] / drivers / video / backlight / lp855x_bl.c
1 /*
2  * TI LP855x Backlight Driver
3  *
4  *                      Copyright (C) 2011 Texas Instruments
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  */
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/i2c.h>
15 #include <linux/backlight.h>
16 #include <linux/err.h>
17 #include <linux/of.h>
18 #include <linux/platform_data/lp855x.h>
19 #include <linux/pwm.h>
21 /* LP8550/1/2/3/6 Registers */
22 #define LP855X_BRIGHTNESS_CTRL          0x00
23 #define LP855X_DEVICE_CTRL              0x01
24 #define LP855X_EEPROM_START             0xA0
25 #define LP855X_EEPROM_END               0xA7
26 #define LP8556_EPROM_START              0xA0
27 #define LP8556_EPROM_END                0xAF
29 /* LP8555/7 Registers */
30 #define LP8557_BL_CMD                   0x00
31 #define LP8557_BL_MASK                  0x01
32 #define LP8557_BL_ON                    0x01
33 #define LP8557_BL_OFF                   0x00
34 #define LP8557_BRIGHTNESS_CTRL          0x04
35 #define LP8557_CONFIG                   0x10
36 #define LP8555_EPROM_START              0x10
37 #define LP8555_EPROM_END                0x7A
38 #define LP8557_EPROM_START              0x10
39 #define LP8557_EPROM_END                0x1E
41 #define DEFAULT_BL_NAME         "lcd-backlight"
42 #define MAX_BRIGHTNESS          255
44 enum lp855x_brightness_ctrl_mode {
45         PWM_BASED = 1,
46         REGISTER_BASED,
47 };
49 struct lp855x;
51 /*
52  * struct lp855x_device_config
53  * @pre_init_device: init device function call before updating the brightness
54  * @reg_brightness: register address for brigthenss control
55  * @reg_devicectrl: register address for device control
56  * @post_init_device: late init device function call
57  */
58 struct lp855x_device_config {
59         int (*pre_init_device)(struct lp855x *);
60         u8 reg_brightness;
61         u8 reg_devicectrl;
62         int (*post_init_device)(struct lp855x *);
63 };
65 struct lp855x {
66         const char *chipname;
67         enum lp855x_chip_id chip_id;
68         enum lp855x_brightness_ctrl_mode mode;
69         struct lp855x_device_config *cfg;
70         struct i2c_client *client;
71         struct backlight_device *bl;
72         struct device *dev;
73         struct lp855x_platform_data *pdata;
74         struct pwm_device *pwm;
75 };
77 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
78 {
79         return i2c_smbus_write_byte_data(lp->client, reg, data);
80 }
82 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
83 {
84         int ret;
85         u8 tmp;
87         ret = i2c_smbus_read_byte_data(lp->client, reg);
88         if (ret < 0) {
89                 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
90                 return ret;
91         }
93         tmp = (u8)ret;
94         tmp &= ~mask;
95         tmp |= data & mask;
97         return lp855x_write_byte(lp, reg, tmp);
98 }
100 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
102         u8 start, end;
104         switch (lp->chip_id) {
105         case LP8550:
106         case LP8551:
107         case LP8552:
108         case LP8553:
109                 start = LP855X_EEPROM_START;
110                 end = LP855X_EEPROM_END;
111                 break;
112         case LP8556:
113                 start = LP8556_EPROM_START;
114                 end = LP8556_EPROM_END;
115                 break;
116         case LP8555:
117                 start = LP8555_EPROM_START;
118                 end = LP8555_EPROM_END;
119                 break;
120         case LP8557:
121                 start = LP8557_EPROM_START;
122                 end = LP8557_EPROM_END;
123                 break;
124         default:
125                 return false;
126         }
128         return addr >= start && addr <= end;
131 static int lp8557_bl_off(struct lp855x *lp)
133         /* BL_ON = 0 before updating EPROM settings */
134         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
135                                 LP8557_BL_OFF);
138 static int lp8557_bl_on(struct lp855x *lp)
140         /* BL_ON = 1 after updating EPROM settings */
141         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
142                                 LP8557_BL_ON);
145 static struct lp855x_device_config lp855x_dev_cfg = {
146         .reg_brightness = LP855X_BRIGHTNESS_CTRL,
147         .reg_devicectrl = LP855X_DEVICE_CTRL,
148 };
150 static struct lp855x_device_config lp8557_dev_cfg = {
151         .reg_brightness = LP8557_BRIGHTNESS_CTRL,
152         .reg_devicectrl = LP8557_CONFIG,
153         .pre_init_device = lp8557_bl_off,
154         .post_init_device = lp8557_bl_on,
155 };
157 /*
158  * Device specific configuration flow
159  *
160  *    a) pre_init_device(optional)
161  *    b) update the brightness register
162  *    c) update device control register
163  *    d) update ROM area(optional)
164  *    e) post_init_device(optional)
165  *
166  */
167 static int lp855x_configure(struct lp855x *lp)
169         u8 val, addr;
170         int i, ret;
171         struct lp855x_platform_data *pd = lp->pdata;
173         switch (lp->chip_id) {
174         case LP8550:
175         case LP8551:
176         case LP8552:
177         case LP8553:
178         case LP8556:
179                 lp->cfg = &lp855x_dev_cfg;
180                 break;
181         case LP8555:
182         case LP8557:
183                 lp->cfg = &lp8557_dev_cfg;
184                 break;
185         default:
186                 return -EINVAL;
187         }
189         if (lp->cfg->pre_init_device) {
190                 ret = lp->cfg->pre_init_device(lp);
191                 if (ret) {
192                         dev_err(lp->dev, "pre init device err: %d\n", ret);
193                         goto err;
194                 }
195         }
197         val = pd->initial_brightness;
198         ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
199         if (ret)
200                 goto err;
202         val = pd->device_control;
203         ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
204         if (ret)
205                 goto err;
207         if (pd->size_program > 0) {
208                 for (i = 0; i < pd->size_program; i++) {
209                         addr = pd->rom_data[i].addr;
210                         val = pd->rom_data[i].val;
211                         if (!lp855x_is_valid_rom_area(lp, addr))
212                                 continue;
214                         ret = lp855x_write_byte(lp, addr, val);
215                         if (ret)
216                                 goto err;
217                 }
218         }
220         if (lp->cfg->post_init_device) {
221                 ret = lp->cfg->post_init_device(lp);
222                 if (ret) {
223                         dev_err(lp->dev, "post init device err: %d\n", ret);
224                         goto err;
225                 }
226         }
228         return 0;
230 err:
231         return ret;
234 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
236         unsigned int period = lp->pdata->period_ns;
237         unsigned int duty = br * period / max_br;
238         struct pwm_device *pwm;
240         /* request pwm device with the consumer name */
241         if (!lp->pwm) {
242                 pwm = devm_pwm_get(lp->dev, lp->chipname);
243                 if (IS_ERR(pwm))
244                         return;
246                 lp->pwm = pwm;
247         }
249         pwm_config(lp->pwm, duty, period);
250         if (duty)
251                 pwm_enable(lp->pwm);
252         else
253                 pwm_disable(lp->pwm);
256 static int lp855x_bl_update_status(struct backlight_device *bl)
258         struct lp855x *lp = bl_get_data(bl);
260         if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
261                 bl->props.brightness = 0;
263         if (lp->mode == PWM_BASED) {
264                 int br = bl->props.brightness;
265                 int max_br = bl->props.max_brightness;
267                 lp855x_pwm_ctrl(lp, br, max_br);
269         } else if (lp->mode == REGISTER_BASED) {
270                 u8 val = bl->props.brightness;
271                 lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
272         }
274         return 0;
277 static int lp855x_bl_get_brightness(struct backlight_device *bl)
279         return bl->props.brightness;
282 static const struct backlight_ops lp855x_bl_ops = {
283         .options = BL_CORE_SUSPENDRESUME,
284         .update_status = lp855x_bl_update_status,
285         .get_brightness = lp855x_bl_get_brightness,
286 };
288 static int lp855x_backlight_register(struct lp855x *lp)
290         struct backlight_device *bl;
291         struct backlight_properties props;
292         struct lp855x_platform_data *pdata = lp->pdata;
293         const char *name = pdata->name ? : DEFAULT_BL_NAME;
295         props.type = BACKLIGHT_PLATFORM;
296         props.max_brightness = MAX_BRIGHTNESS;
298         if (pdata->initial_brightness > props.max_brightness)
299                 pdata->initial_brightness = props.max_brightness;
301         props.brightness = pdata->initial_brightness;
303         bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp,
304                                        &lp855x_bl_ops, &props);
305         if (IS_ERR(bl))
306                 return PTR_ERR(bl);
308         lp->bl = bl;
310         return 0;
313 static ssize_t lp855x_get_chip_id(struct device *dev,
314                                 struct device_attribute *attr, char *buf)
316         struct lp855x *lp = dev_get_drvdata(dev);
317         return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname);
320 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
321                                      struct device_attribute *attr, char *buf)
323         struct lp855x *lp = dev_get_drvdata(dev);
324         char *strmode = NULL;
326         if (lp->mode == PWM_BASED)
327                 strmode = "pwm based";
328         else if (lp->mode == REGISTER_BASED)
329                 strmode = "register based";
331         return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
334 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
335 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
337 static struct attribute *lp855x_attributes[] = {
338         &dev_attr_chip_id.attr,
339         &dev_attr_bl_ctl_mode.attr,
340         NULL,
341 };
343 static const struct attribute_group lp855x_attr_group = {
344         .attrs = lp855x_attributes,
345 };
347 #ifdef CONFIG_OF
348 static int lp855x_parse_dt(struct device *dev, struct device_node *node)
350         struct lp855x_platform_data *pdata;
351         int rom_length;
353         if (!node) {
354                 dev_err(dev, "no platform data\n");
355                 return -EINVAL;
356         }
358         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
359         if (!pdata)
360                 return -ENOMEM;
362         of_property_read_string(node, "bl-name", &pdata->name);
363         of_property_read_u8(node, "dev-ctrl", &pdata->device_control);
364         of_property_read_u8(node, "init-brt", &pdata->initial_brightness);
365         of_property_read_u32(node, "pwm-period", &pdata->period_ns);
367         /* Fill ROM platform data if defined */
368         rom_length = of_get_child_count(node);
369         if (rom_length > 0) {
370                 struct lp855x_rom_data *rom;
371                 struct device_node *child;
372                 int i = 0;
374                 rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL);
375                 if (!rom)
376                         return -ENOMEM;
378                 for_each_child_of_node(node, child) {
379                         of_property_read_u8(child, "rom-addr", &rom[i].addr);
380                         of_property_read_u8(child, "rom-val", &rom[i].val);
381                         i++;
382                 }
384                 pdata->size_program = rom_length;
385                 pdata->rom_data = &rom[0];
386         }
388         dev->platform_data = pdata;
390         return 0;
392 #else
393 static int lp855x_parse_dt(struct device *dev, struct device_node *node)
395         return -EINVAL;
397 #endif
399 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
401         struct lp855x *lp;
402         struct lp855x_platform_data *pdata = dev_get_platdata(&cl->dev);
403         struct device_node *node = cl->dev.of_node;
404         int ret;
406         if (!pdata) {
407                 ret = lp855x_parse_dt(&cl->dev, node);
408                 if (ret < 0)
409                         return ret;
411                 pdata = dev_get_platdata(&cl->dev);
412         }
414         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
415                 return -EIO;
417         lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
418         if (!lp)
419                 return -ENOMEM;
421         if (pdata->period_ns > 0)
422                 lp->mode = PWM_BASED;
423         else
424                 lp->mode = REGISTER_BASED;
426         lp->client = cl;
427         lp->dev = &cl->dev;
428         lp->pdata = pdata;
429         lp->chipname = id->name;
430         lp->chip_id = id->driver_data;
431         i2c_set_clientdata(cl, lp);
433         ret = lp855x_configure(lp);
434         if (ret) {
435                 dev_err(lp->dev, "device config err: %d", ret);
436                 return ret;
437         }
439         ret = lp855x_backlight_register(lp);
440         if (ret) {
441                 dev_err(lp->dev,
442                         "failed to register backlight. err: %d\n", ret);
443                 return ret;
444         }
446         ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
447         if (ret) {
448                 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
449                 return ret;
450         }
452         backlight_update_status(lp->bl);
453         return 0;
456 static int lp855x_remove(struct i2c_client *cl)
458         struct lp855x *lp = i2c_get_clientdata(cl);
460         lp->bl->props.brightness = 0;
461         backlight_update_status(lp->bl);
462         sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
464         return 0;
467 static const struct of_device_id lp855x_dt_ids[] = {
468         { .compatible = "ti,lp8550", },
469         { .compatible = "ti,lp8551", },
470         { .compatible = "ti,lp8552", },
471         { .compatible = "ti,lp8553", },
472         { .compatible = "ti,lp8555", },
473         { .compatible = "ti,lp8556", },
474         { .compatible = "ti,lp8557", },
475         { }
476 };
477 MODULE_DEVICE_TABLE(of, lp855x_dt_ids);
479 static const struct i2c_device_id lp855x_ids[] = {
480         {"lp8550", LP8550},
481         {"lp8551", LP8551},
482         {"lp8552", LP8552},
483         {"lp8553", LP8553},
484         {"lp8555", LP8555},
485         {"lp8556", LP8556},
486         {"lp8557", LP8557},
487         { }
488 };
489 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
491 static struct i2c_driver lp855x_driver = {
492         .driver = {
493                    .name = "lp855x",
494                    .of_match_table = of_match_ptr(lp855x_dt_ids),
495                    },
496         .probe = lp855x_probe,
497         .remove = lp855x_remove,
498         .id_table = lp855x_ids,
499 };
501 module_i2c_driver(lp855x_driver);
503 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
504 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
505 MODULE_LICENSE("GPL");