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7be865ab KM |
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> | |
f7f95056 | 17 | #include <linux/platform_data/lp855x.h> |
8cc9764c | 18 | #include <linux/pwm.h> |
7be865ab KM |
19 | |
20 | /* Registers */ | |
a1fcb2e3 KM |
21 | #define BRIGHTNESS_CTRL 0x00 |
22 | #define DEVICE_CTRL 0x01 | |
23 | #define EEPROM_START 0xA0 | |
24 | #define EEPROM_END 0xA7 | |
25 | #define EPROM_START 0xA0 | |
26 | #define EPROM_END 0xAF | |
7be865ab KM |
27 | |
28 | #define BUF_SIZE 20 | |
29 | #define DEFAULT_BL_NAME "lcd-backlight" | |
30 | #define MAX_BRIGHTNESS 255 | |
31 | ||
32 | struct lp855x { | |
33 | const char *chipname; | |
34 | enum lp855x_chip_id chip_id; | |
35 | struct i2c_client *client; | |
36 | struct backlight_device *bl; | |
37 | struct device *dev; | |
7be865ab | 38 | struct lp855x_platform_data *pdata; |
8cc9764c | 39 | struct pwm_device *pwm; |
7be865ab KM |
40 | }; |
41 | ||
42 | static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data) | |
43 | { | |
44 | int ret; | |
45 | ||
7be865ab KM |
46 | ret = i2c_smbus_read_byte_data(lp->client, reg); |
47 | if (ret < 0) { | |
7be865ab KM |
48 | dev_err(lp->dev, "failed to read 0x%.2x\n", reg); |
49 | return ret; | |
50 | } | |
7be865ab KM |
51 | |
52 | *data = (u8)ret; | |
53 | return 0; | |
54 | } | |
55 | ||
56 | static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) | |
57 | { | |
eaa4d02f | 58 | return i2c_smbus_write_byte_data(lp->client, reg, data); |
7be865ab KM |
59 | } |
60 | ||
61 | static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr) | |
62 | { | |
63 | u8 start, end; | |
64 | ||
65 | switch (lp->chip_id) { | |
66 | case LP8550: | |
67 | case LP8551: | |
68 | case LP8552: | |
69 | case LP8553: | |
70 | start = EEPROM_START; | |
71 | end = EEPROM_END; | |
72 | break; | |
73 | case LP8556: | |
74 | start = EPROM_START; | |
75 | end = EPROM_END; | |
76 | break; | |
77 | default: | |
78 | return false; | |
79 | } | |
80 | ||
81 | return (addr >= start && addr <= end); | |
82 | } | |
83 | ||
84 | static int lp855x_init_registers(struct lp855x *lp) | |
85 | { | |
86 | u8 val, addr; | |
87 | int i, ret; | |
88 | struct lp855x_platform_data *pd = lp->pdata; | |
89 | ||
90 | val = pd->initial_brightness; | |
91 | ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val); | |
92 | if (ret) | |
93 | return ret; | |
94 | ||
95 | val = pd->device_control; | |
96 | ret = lp855x_write_byte(lp, DEVICE_CTRL, val); | |
97 | if (ret) | |
98 | return ret; | |
99 | ||
100 | if (pd->load_new_rom_data && pd->size_program) { | |
101 | for (i = 0; i < pd->size_program; i++) { | |
102 | addr = pd->rom_data[i].addr; | |
103 | val = pd->rom_data[i].val; | |
104 | if (!lp855x_is_valid_rom_area(lp, addr)) | |
105 | continue; | |
106 | ||
107 | ret = lp855x_write_byte(lp, addr, val); | |
108 | if (ret) | |
109 | return ret; | |
110 | } | |
111 | } | |
112 | ||
113 | return ret; | |
114 | } | |
115 | ||
8cc9764c KM |
116 | static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br) |
117 | { | |
118 | unsigned int period = lp->pdata->period_ns; | |
119 | unsigned int duty = br * period / max_br; | |
120 | struct pwm_device *pwm; | |
121 | ||
122 | /* request pwm device with the consumer name */ | |
123 | if (!lp->pwm) { | |
124 | pwm = devm_pwm_get(lp->dev, lp->chipname); | |
125 | if (IS_ERR(pwm)) | |
126 | return; | |
127 | ||
128 | lp->pwm = pwm; | |
129 | } | |
130 | ||
131 | pwm_config(lp->pwm, duty, period); | |
132 | if (duty) | |
133 | pwm_enable(lp->pwm); | |
134 | else | |
135 | pwm_disable(lp->pwm); | |
136 | } | |
137 | ||
7be865ab KM |
138 | static int lp855x_bl_update_status(struct backlight_device *bl) |
139 | { | |
140 | struct lp855x *lp = bl_get_data(bl); | |
141 | enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; | |
142 | ||
143 | if (bl->props.state & BL_CORE_SUSPENDED) | |
144 | bl->props.brightness = 0; | |
145 | ||
146 | if (mode == PWM_BASED) { | |
7be865ab KM |
147 | int br = bl->props.brightness; |
148 | int max_br = bl->props.max_brightness; | |
149 | ||
8cc9764c | 150 | lp855x_pwm_ctrl(lp, br, max_br); |
7be865ab KM |
151 | |
152 | } else if (mode == REGISTER_BASED) { | |
153 | u8 val = bl->props.brightness; | |
154 | lp855x_write_byte(lp, BRIGHTNESS_CTRL, val); | |
155 | } | |
156 | ||
157 | return 0; | |
158 | } | |
159 | ||
160 | static int lp855x_bl_get_brightness(struct backlight_device *bl) | |
161 | { | |
162 | struct lp855x *lp = bl_get_data(bl); | |
163 | enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; | |
164 | ||
8cc9764c | 165 | if (mode == REGISTER_BASED) { |
7be865ab KM |
166 | u8 val = 0; |
167 | ||
168 | lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val); | |
169 | bl->props.brightness = val; | |
170 | } | |
171 | ||
172 | return bl->props.brightness; | |
173 | } | |
174 | ||
175 | static const struct backlight_ops lp855x_bl_ops = { | |
176 | .options = BL_CORE_SUSPENDRESUME, | |
177 | .update_status = lp855x_bl_update_status, | |
178 | .get_brightness = lp855x_bl_get_brightness, | |
179 | }; | |
180 | ||
181 | static int lp855x_backlight_register(struct lp855x *lp) | |
182 | { | |
183 | struct backlight_device *bl; | |
184 | struct backlight_properties props; | |
185 | struct lp855x_platform_data *pdata = lp->pdata; | |
186 | char *name = pdata->name ? : DEFAULT_BL_NAME; | |
187 | ||
188 | props.type = BACKLIGHT_PLATFORM; | |
189 | props.max_brightness = MAX_BRIGHTNESS; | |
190 | ||
191 | if (pdata->initial_brightness > props.max_brightness) | |
192 | pdata->initial_brightness = props.max_brightness; | |
193 | ||
194 | props.brightness = pdata->initial_brightness; | |
195 | ||
196 | bl = backlight_device_register(name, lp->dev, lp, | |
197 | &lp855x_bl_ops, &props); | |
198 | if (IS_ERR(bl)) | |
199 | return PTR_ERR(bl); | |
200 | ||
201 | lp->bl = bl; | |
202 | ||
203 | return 0; | |
204 | } | |
205 | ||
206 | static void lp855x_backlight_unregister(struct lp855x *lp) | |
207 | { | |
208 | if (lp->bl) | |
209 | backlight_device_unregister(lp->bl); | |
210 | } | |
211 | ||
212 | static ssize_t lp855x_get_chip_id(struct device *dev, | |
213 | struct device_attribute *attr, char *buf) | |
214 | { | |
215 | struct lp855x *lp = dev_get_drvdata(dev); | |
216 | return scnprintf(buf, BUF_SIZE, "%s\n", lp->chipname); | |
217 | } | |
218 | ||
219 | static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, | |
220 | struct device_attribute *attr, char *buf) | |
221 | { | |
222 | struct lp855x *lp = dev_get_drvdata(dev); | |
223 | enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; | |
224 | char *strmode = NULL; | |
225 | ||
226 | if (mode == PWM_BASED) | |
227 | strmode = "pwm based"; | |
228 | else if (mode == REGISTER_BASED) | |
229 | strmode = "register based"; | |
230 | ||
231 | return scnprintf(buf, BUF_SIZE, "%s\n", strmode); | |
232 | } | |
233 | ||
234 | static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); | |
235 | static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); | |
236 | ||
237 | static struct attribute *lp855x_attributes[] = { | |
238 | &dev_attr_chip_id.attr, | |
239 | &dev_attr_bl_ctl_mode.attr, | |
240 | NULL, | |
241 | }; | |
242 | ||
243 | static const struct attribute_group lp855x_attr_group = { | |
244 | .attrs = lp855x_attributes, | |
245 | }; | |
246 | ||
247 | static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) | |
248 | { | |
249 | struct lp855x *lp; | |
250 | struct lp855x_platform_data *pdata = cl->dev.platform_data; | |
251 | enum lp855x_brightness_ctrl_mode mode; | |
252 | int ret; | |
253 | ||
254 | if (!pdata) { | |
255 | dev_err(&cl->dev, "no platform data supplied\n"); | |
256 | return -EINVAL; | |
257 | } | |
258 | ||
259 | if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) | |
260 | return -EIO; | |
261 | ||
262 | lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); | |
263 | if (!lp) | |
264 | return -ENOMEM; | |
265 | ||
266 | mode = pdata->mode; | |
267 | lp->client = cl; | |
268 | lp->dev = &cl->dev; | |
269 | lp->pdata = pdata; | |
270 | lp->chipname = id->name; | |
271 | lp->chip_id = id->driver_data; | |
272 | i2c_set_clientdata(cl, lp); | |
273 | ||
7be865ab KM |
274 | ret = lp855x_init_registers(lp); |
275 | if (ret) { | |
276 | dev_err(lp->dev, "i2c communication err: %d", ret); | |
277 | if (mode == REGISTER_BASED) | |
278 | goto err_dev; | |
279 | } | |
280 | ||
281 | ret = lp855x_backlight_register(lp); | |
282 | if (ret) { | |
283 | dev_err(lp->dev, | |
284 | "failed to register backlight. err: %d\n", ret); | |
285 | goto err_dev; | |
286 | } | |
287 | ||
288 | ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); | |
289 | if (ret) { | |
290 | dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); | |
291 | goto err_sysfs; | |
292 | } | |
293 | ||
294 | backlight_update_status(lp->bl); | |
295 | return 0; | |
296 | ||
297 | err_sysfs: | |
298 | lp855x_backlight_unregister(lp); | |
299 | err_dev: | |
300 | return ret; | |
301 | } | |
302 | ||
7e4b9d0b | 303 | static int lp855x_remove(struct i2c_client *cl) |
7be865ab KM |
304 | { |
305 | struct lp855x *lp = i2c_get_clientdata(cl); | |
306 | ||
307 | lp->bl->props.brightness = 0; | |
308 | backlight_update_status(lp->bl); | |
309 | sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); | |
310 | lp855x_backlight_unregister(lp); | |
311 | ||
312 | return 0; | |
313 | } | |
314 | ||
315 | static const struct i2c_device_id lp855x_ids[] = { | |
316 | {"lp8550", LP8550}, | |
317 | {"lp8551", LP8551}, | |
318 | {"lp8552", LP8552}, | |
319 | {"lp8553", LP8553}, | |
320 | {"lp8556", LP8556}, | |
321 | { } | |
322 | }; | |
323 | MODULE_DEVICE_TABLE(i2c, lp855x_ids); | |
324 | ||
325 | static struct i2c_driver lp855x_driver = { | |
326 | .driver = { | |
327 | .name = "lp855x", | |
328 | }, | |
329 | .probe = lp855x_probe, | |
d1723fa2 | 330 | .remove = lp855x_remove, |
7be865ab KM |
331 | .id_table = lp855x_ids, |
332 | }; | |
333 | ||
334 | module_i2c_driver(lp855x_driver); | |
335 | ||
336 | MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); | |
337 | MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); | |
338 | MODULE_LICENSE("GPL"); |