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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 | */ | |
11 | ||
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/lp855x.h> | |
18 | ||
19 | /* Registers */ | |
20 | #define BRIGHTNESS_CTRL (0x00) | |
21 | #define DEVICE_CTRL (0x01) | |
22 | ||
23 | #define BUF_SIZE 20 | |
24 | #define DEFAULT_BL_NAME "lcd-backlight" | |
25 | #define MAX_BRIGHTNESS 255 | |
26 | ||
27 | struct lp855x { | |
28 | const char *chipname; | |
29 | enum lp855x_chip_id chip_id; | |
30 | struct i2c_client *client; | |
31 | struct backlight_device *bl; | |
32 | struct device *dev; | |
33 | struct mutex xfer_lock; | |
34 | struct lp855x_platform_data *pdata; | |
35 | }; | |
36 | ||
37 | static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data) | |
38 | { | |
39 | int ret; | |
40 | ||
41 | mutex_lock(&lp->xfer_lock); | |
42 | ret = i2c_smbus_read_byte_data(lp->client, reg); | |
43 | if (ret < 0) { | |
44 | mutex_unlock(&lp->xfer_lock); | |
45 | dev_err(lp->dev, "failed to read 0x%.2x\n", reg); | |
46 | return ret; | |
47 | } | |
48 | mutex_unlock(&lp->xfer_lock); | |
49 | ||
50 | *data = (u8)ret; | |
51 | return 0; | |
52 | } | |
53 | ||
54 | static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) | |
55 | { | |
56 | int ret; | |
57 | ||
58 | mutex_lock(&lp->xfer_lock); | |
59 | ret = i2c_smbus_write_byte_data(lp->client, reg, data); | |
60 | mutex_unlock(&lp->xfer_lock); | |
61 | ||
62 | return ret; | |
63 | } | |
64 | ||
65 | static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr) | |
66 | { | |
67 | u8 start, end; | |
68 | ||
69 | switch (lp->chip_id) { | |
70 | case LP8550: | |
71 | case LP8551: | |
72 | case LP8552: | |
73 | case LP8553: | |
74 | start = EEPROM_START; | |
75 | end = EEPROM_END; | |
76 | break; | |
77 | case LP8556: | |
78 | start = EPROM_START; | |
79 | end = EPROM_END; | |
80 | break; | |
81 | default: | |
82 | return false; | |
83 | } | |
84 | ||
85 | return (addr >= start && addr <= end); | |
86 | } | |
87 | ||
88 | static int lp855x_init_registers(struct lp855x *lp) | |
89 | { | |
90 | u8 val, addr; | |
91 | int i, ret; | |
92 | struct lp855x_platform_data *pd = lp->pdata; | |
93 | ||
94 | val = pd->initial_brightness; | |
95 | ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val); | |
96 | if (ret) | |
97 | return ret; | |
98 | ||
99 | val = pd->device_control; | |
100 | ret = lp855x_write_byte(lp, DEVICE_CTRL, val); | |
101 | if (ret) | |
102 | return ret; | |
103 | ||
104 | if (pd->load_new_rom_data && pd->size_program) { | |
105 | for (i = 0; i < pd->size_program; i++) { | |
106 | addr = pd->rom_data[i].addr; | |
107 | val = pd->rom_data[i].val; | |
108 | if (!lp855x_is_valid_rom_area(lp, addr)) | |
109 | continue; | |
110 | ||
111 | ret = lp855x_write_byte(lp, addr, val); | |
112 | if (ret) | |
113 | return ret; | |
114 | } | |
115 | } | |
116 | ||
117 | return ret; | |
118 | } | |
119 | ||
120 | static int lp855x_bl_update_status(struct backlight_device *bl) | |
121 | { | |
122 | struct lp855x *lp = bl_get_data(bl); | |
123 | enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; | |
124 | ||
125 | if (bl->props.state & BL_CORE_SUSPENDED) | |
126 | bl->props.brightness = 0; | |
127 | ||
128 | if (mode == PWM_BASED) { | |
129 | struct lp855x_pwm_data *pd = &lp->pdata->pwm_data; | |
130 | int br = bl->props.brightness; | |
131 | int max_br = bl->props.max_brightness; | |
132 | ||
133 | if (pd->pwm_set_intensity) | |
134 | pd->pwm_set_intensity(br, max_br); | |
135 | ||
136 | } else if (mode == REGISTER_BASED) { | |
137 | u8 val = bl->props.brightness; | |
138 | lp855x_write_byte(lp, BRIGHTNESS_CTRL, val); | |
139 | } | |
140 | ||
141 | return 0; | |
142 | } | |
143 | ||
144 | static int lp855x_bl_get_brightness(struct backlight_device *bl) | |
145 | { | |
146 | struct lp855x *lp = bl_get_data(bl); | |
147 | enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; | |
148 | ||
149 | if (mode == PWM_BASED) { | |
150 | struct lp855x_pwm_data *pd = &lp->pdata->pwm_data; | |
151 | int max_br = bl->props.max_brightness; | |
152 | ||
153 | if (pd->pwm_get_intensity) | |
154 | bl->props.brightness = pd->pwm_get_intensity(max_br); | |
155 | ||
156 | } else if (mode == REGISTER_BASED) { | |
157 | u8 val = 0; | |
158 | ||
159 | lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val); | |
160 | bl->props.brightness = val; | |
161 | } | |
162 | ||
163 | return bl->props.brightness; | |
164 | } | |
165 | ||
166 | static const struct backlight_ops lp855x_bl_ops = { | |
167 | .options = BL_CORE_SUSPENDRESUME, | |
168 | .update_status = lp855x_bl_update_status, | |
169 | .get_brightness = lp855x_bl_get_brightness, | |
170 | }; | |
171 | ||
172 | static int lp855x_backlight_register(struct lp855x *lp) | |
173 | { | |
174 | struct backlight_device *bl; | |
175 | struct backlight_properties props; | |
176 | struct lp855x_platform_data *pdata = lp->pdata; | |
177 | char *name = pdata->name ? : DEFAULT_BL_NAME; | |
178 | ||
179 | props.type = BACKLIGHT_PLATFORM; | |
180 | props.max_brightness = MAX_BRIGHTNESS; | |
181 | ||
182 | if (pdata->initial_brightness > props.max_brightness) | |
183 | pdata->initial_brightness = props.max_brightness; | |
184 | ||
185 | props.brightness = pdata->initial_brightness; | |
186 | ||
187 | bl = backlight_device_register(name, lp->dev, lp, | |
188 | &lp855x_bl_ops, &props); | |
189 | if (IS_ERR(bl)) | |
190 | return PTR_ERR(bl); | |
191 | ||
192 | lp->bl = bl; | |
193 | ||
194 | return 0; | |
195 | } | |
196 | ||
197 | static void lp855x_backlight_unregister(struct lp855x *lp) | |
198 | { | |
199 | if (lp->bl) | |
200 | backlight_device_unregister(lp->bl); | |
201 | } | |
202 | ||
203 | static ssize_t lp855x_get_chip_id(struct device *dev, | |
204 | struct device_attribute *attr, char *buf) | |
205 | { | |
206 | struct lp855x *lp = dev_get_drvdata(dev); | |
207 | return scnprintf(buf, BUF_SIZE, "%s\n", lp->chipname); | |
208 | } | |
209 | ||
210 | static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, | |
211 | struct device_attribute *attr, char *buf) | |
212 | { | |
213 | struct lp855x *lp = dev_get_drvdata(dev); | |
214 | enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; | |
215 | char *strmode = NULL; | |
216 | ||
217 | if (mode == PWM_BASED) | |
218 | strmode = "pwm based"; | |
219 | else if (mode == REGISTER_BASED) | |
220 | strmode = "register based"; | |
221 | ||
222 | return scnprintf(buf, BUF_SIZE, "%s\n", strmode); | |
223 | } | |
224 | ||
225 | static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); | |
226 | static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); | |
227 | ||
228 | static struct attribute *lp855x_attributes[] = { | |
229 | &dev_attr_chip_id.attr, | |
230 | &dev_attr_bl_ctl_mode.attr, | |
231 | NULL, | |
232 | }; | |
233 | ||
234 | static const struct attribute_group lp855x_attr_group = { | |
235 | .attrs = lp855x_attributes, | |
236 | }; | |
237 | ||
238 | static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) | |
239 | { | |
240 | struct lp855x *lp; | |
241 | struct lp855x_platform_data *pdata = cl->dev.platform_data; | |
242 | enum lp855x_brightness_ctrl_mode mode; | |
243 | int ret; | |
244 | ||
245 | if (!pdata) { | |
246 | dev_err(&cl->dev, "no platform data supplied\n"); | |
247 | return -EINVAL; | |
248 | } | |
249 | ||
250 | if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) | |
251 | return -EIO; | |
252 | ||
253 | lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); | |
254 | if (!lp) | |
255 | return -ENOMEM; | |
256 | ||
257 | mode = pdata->mode; | |
258 | lp->client = cl; | |
259 | lp->dev = &cl->dev; | |
260 | lp->pdata = pdata; | |
261 | lp->chipname = id->name; | |
262 | lp->chip_id = id->driver_data; | |
263 | i2c_set_clientdata(cl, lp); | |
264 | ||
265 | mutex_init(&lp->xfer_lock); | |
266 | ||
267 | ret = lp855x_init_registers(lp); | |
268 | if (ret) { | |
269 | dev_err(lp->dev, "i2c communication err: %d", ret); | |
270 | if (mode == REGISTER_BASED) | |
271 | goto err_dev; | |
272 | } | |
273 | ||
274 | ret = lp855x_backlight_register(lp); | |
275 | if (ret) { | |
276 | dev_err(lp->dev, | |
277 | "failed to register backlight. err: %d\n", ret); | |
278 | goto err_dev; | |
279 | } | |
280 | ||
281 | ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); | |
282 | if (ret) { | |
283 | dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); | |
284 | goto err_sysfs; | |
285 | } | |
286 | ||
287 | backlight_update_status(lp->bl); | |
288 | return 0; | |
289 | ||
290 | err_sysfs: | |
291 | lp855x_backlight_unregister(lp); | |
292 | err_dev: | |
293 | return ret; | |
294 | } | |
295 | ||
296 | static int __devexit lp855x_remove(struct i2c_client *cl) | |
297 | { | |
298 | struct lp855x *lp = i2c_get_clientdata(cl); | |
299 | ||
300 | lp->bl->props.brightness = 0; | |
301 | backlight_update_status(lp->bl); | |
302 | sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); | |
303 | lp855x_backlight_unregister(lp); | |
304 | ||
305 | return 0; | |
306 | } | |
307 | ||
308 | static const struct i2c_device_id lp855x_ids[] = { | |
309 | {"lp8550", LP8550}, | |
310 | {"lp8551", LP8551}, | |
311 | {"lp8552", LP8552}, | |
312 | {"lp8553", LP8553}, | |
313 | {"lp8556", LP8556}, | |
314 | { } | |
315 | }; | |
316 | MODULE_DEVICE_TABLE(i2c, lp855x_ids); | |
317 | ||
318 | static struct i2c_driver lp855x_driver = { | |
319 | .driver = { | |
320 | .name = "lp855x", | |
321 | }, | |
322 | .probe = lp855x_probe, | |
323 | .remove = __devexit_p(lp855x_remove), | |
324 | .id_table = lp855x_ids, | |
325 | }; | |
326 | ||
327 | module_i2c_driver(lp855x_driver); | |
328 | ||
329 | MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); | |
330 | MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); | |
331 | MODULE_LICENSE("GPL"); |