backlight: add new lp8788 backlight driver
[linux-3.10.git] / drivers / video / backlight / lp8788_bl.c
1 /*
2  * TI LP8788 MFD - backlight driver
3  *
4  * Copyright 2012 Texas Instruments
5  *
6  * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11  *
12  */
13
14 #include <linux/backlight.h>
15 #include <linux/err.h>
16 #include <linux/mfd/lp8788.h>
17 #include <linux/module.h>
18 #include <linux/platform_device.h>
19 #include <linux/pwm.h>
20 #include <linux/slab.h>
21
22 /* Register address */
23 #define LP8788_BL_CONFIG                0x96
24 #define LP8788_BL_EN                    BIT(0)
25 #define LP8788_BL_PWM_INPUT_EN          BIT(5)
26 #define LP8788_BL_FULLSCALE_SHIFT       2
27 #define LP8788_BL_DIM_MODE_SHIFT        1
28 #define LP8788_BL_PWM_POLARITY_SHIFT    6
29
30 #define LP8788_BL_BRIGHTNESS            0x97
31
32 #define LP8788_BL_RAMP                  0x98
33 #define LP8788_BL_RAMP_RISE_SHIFT       4
34
35 #define MAX_BRIGHTNESS                  127
36 #define DEFAULT_BL_NAME                 "lcd-backlight"
37
38 struct lp8788_bl_config {
39         enum lp8788_bl_ctrl_mode bl_mode;
40         enum lp8788_bl_dim_mode dim_mode;
41         enum lp8788_bl_full_scale_current full_scale;
42         enum lp8788_bl_ramp_step rise_time;
43         enum lp8788_bl_ramp_step fall_time;
44         enum pwm_polarity pwm_pol;
45 };
46
47 struct lp8788_bl {
48         struct lp8788 *lp;
49         struct backlight_device *bl_dev;
50         struct lp8788_backlight_platform_data *pdata;
51         enum lp8788_bl_ctrl_mode mode;
52         struct pwm_device *pwm;
53 };
54
55 struct lp8788_bl_config default_bl_config = {
56         .bl_mode    = LP8788_BL_REGISTER_ONLY,
57         .dim_mode   = LP8788_DIM_EXPONENTIAL,
58         .full_scale = LP8788_FULLSCALE_1900uA,
59         .rise_time  = LP8788_RAMP_8192us,
60         .fall_time  = LP8788_RAMP_8192us,
61         .pwm_pol    = PWM_POLARITY_NORMAL,
62 };
63
64 static inline bool is_brightness_ctrl_by_pwm(enum lp8788_bl_ctrl_mode mode)
65 {
66         return (mode == LP8788_BL_COMB_PWM_BASED);
67 }
68
69 static inline bool is_brightness_ctrl_by_register(enum lp8788_bl_ctrl_mode mode)
70 {
71         return (mode == LP8788_BL_REGISTER_ONLY ||
72                 mode == LP8788_BL_COMB_REGISTER_BASED);
73 }
74
75 static int lp8788_backlight_configure(struct lp8788_bl *bl)
76 {
77         struct lp8788_backlight_platform_data *pdata = bl->pdata;
78         struct lp8788_bl_config *cfg = &default_bl_config;
79         int ret;
80         u8 val;
81
82         /*
83          * Update chip configuration if platform data exists,
84          * otherwise use the default settings.
85          */
86         if (pdata) {
87                 cfg->bl_mode    = pdata->bl_mode;
88                 cfg->dim_mode   = pdata->dim_mode;
89                 cfg->full_scale = pdata->full_scale;
90                 cfg->rise_time  = pdata->rise_time;
91                 cfg->fall_time  = pdata->fall_time;
92                 cfg->pwm_pol    = pdata->pwm_pol;
93         }
94
95         /* Brightness ramp up/down */
96         val = (cfg->rise_time << LP8788_BL_RAMP_RISE_SHIFT) | cfg->fall_time;
97         ret = lp8788_write_byte(bl->lp, LP8788_BL_RAMP, val);
98         if (ret)
99                 return ret;
100
101         /* Fullscale current setting */
102         val = (cfg->full_scale << LP8788_BL_FULLSCALE_SHIFT) |
103                 (cfg->dim_mode << LP8788_BL_DIM_MODE_SHIFT);
104
105         /* Brightness control mode */
106         switch (cfg->bl_mode) {
107         case LP8788_BL_REGISTER_ONLY:
108                 val |= LP8788_BL_EN;
109                 break;
110         case LP8788_BL_COMB_PWM_BASED:
111         case LP8788_BL_COMB_REGISTER_BASED:
112                 val |= LP8788_BL_EN | LP8788_BL_PWM_INPUT_EN |
113                         (cfg->pwm_pol << LP8788_BL_PWM_POLARITY_SHIFT);
114                 break;
115         default:
116                 dev_err(bl->lp->dev, "invalid mode: %d\n", cfg->bl_mode);
117                 return -EINVAL;
118         }
119
120         bl->mode = cfg->bl_mode;
121
122         return lp8788_write_byte(bl->lp, LP8788_BL_CONFIG, val);
123 }
124
125 static void lp8788_pwm_ctrl(struct lp8788_bl *bl, int br, int max_br)
126 {
127         unsigned int period;
128         unsigned int duty;
129         struct device *dev;
130         struct pwm_device *pwm;
131
132         if (!bl->pdata)
133                 return;
134
135         period = bl->pdata->period_ns;
136         duty = br * period / max_br;
137         dev = bl->lp->dev;
138
139         /* request PWM device with the consumer name */
140         if (!bl->pwm) {
141                 pwm = devm_pwm_get(dev, LP8788_DEV_BACKLIGHT);
142                 if (IS_ERR(pwm)) {
143                         dev_err(dev, "can not get PWM device\n");
144                         return;
145                 }
146
147                 bl->pwm = pwm;
148         }
149
150         pwm_config(bl->pwm, duty, period);
151         if (duty)
152                 pwm_enable(bl->pwm);
153         else
154                 pwm_disable(bl->pwm);
155 }
156
157 static int lp8788_bl_update_status(struct backlight_device *bl_dev)
158 {
159         struct lp8788_bl *bl = bl_get_data(bl_dev);
160         enum lp8788_bl_ctrl_mode mode = bl->mode;
161
162         if (bl_dev->props.state & BL_CORE_SUSPENDED)
163                 bl_dev->props.brightness = 0;
164
165         if (is_brightness_ctrl_by_pwm(mode)) {
166                 int brt = bl_dev->props.brightness;
167                 int max = bl_dev->props.max_brightness;
168
169                 lp8788_pwm_ctrl(bl, brt, max);
170         } else if (is_brightness_ctrl_by_register(mode)) {
171                 u8 brt = bl_dev->props.brightness;
172
173                 lp8788_write_byte(bl->lp, LP8788_BL_BRIGHTNESS, brt);
174         }
175
176         return 0;
177 }
178
179 static int lp8788_bl_get_brightness(struct backlight_device *bl_dev)
180 {
181         return bl_dev->props.brightness;
182 }
183
184 static const struct backlight_ops lp8788_bl_ops = {
185         .options = BL_CORE_SUSPENDRESUME,
186         .update_status = lp8788_bl_update_status,
187         .get_brightness = lp8788_bl_get_brightness,
188 };
189
190 static int lp8788_backlight_register(struct lp8788_bl *bl)
191 {
192         struct backlight_device *bl_dev;
193         struct backlight_properties props;
194         struct lp8788_backlight_platform_data *pdata = bl->pdata;
195         int init_brt;
196         char *name;
197
198         props.type = BACKLIGHT_PLATFORM;
199         props.max_brightness = MAX_BRIGHTNESS;
200
201         /* Initial brightness */
202         if (pdata)
203                 init_brt = min_t(int, pdata->initial_brightness,
204                                 props.max_brightness);
205         else
206                 init_brt = 0;
207
208         props.brightness = init_brt;
209
210         /* Backlight device name */
211         if (!pdata || !pdata->name)
212                 name = DEFAULT_BL_NAME;
213         else
214                 name = pdata->name;
215
216         bl_dev = backlight_device_register(name, bl->lp->dev, bl,
217                                        &lp8788_bl_ops, &props);
218         if (IS_ERR(bl_dev))
219                 return PTR_ERR(bl_dev);
220
221         bl->bl_dev = bl_dev;
222
223         return 0;
224 }
225
226 static void lp8788_backlight_unregister(struct lp8788_bl *bl)
227 {
228         struct backlight_device *bl_dev = bl->bl_dev;
229
230         if (bl_dev)
231                 backlight_device_unregister(bl_dev);
232 }
233
234 static ssize_t lp8788_get_bl_ctl_mode(struct device *dev,
235                                      struct device_attribute *attr, char *buf)
236 {
237         struct lp8788_bl *bl = dev_get_drvdata(dev);
238         enum lp8788_bl_ctrl_mode mode = bl->mode;
239         char *strmode;
240
241         if (is_brightness_ctrl_by_pwm(mode))
242                 strmode = "PWM based";
243         else if (is_brightness_ctrl_by_register(mode))
244                 strmode = "Register based";
245         else
246                 strmode = "Invalid mode";
247
248         return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
249 }
250
251 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp8788_get_bl_ctl_mode, NULL);
252
253 static struct attribute *lp8788_attributes[] = {
254         &dev_attr_bl_ctl_mode.attr,
255         NULL,
256 };
257
258 static const struct attribute_group lp8788_attr_group = {
259         .attrs = lp8788_attributes,
260 };
261
262 static int lp8788_backlight_probe(struct platform_device *pdev)
263 {
264         struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
265         struct lp8788_bl *bl;
266         int ret;
267
268         bl = devm_kzalloc(lp->dev, sizeof(struct lp8788_bl), GFP_KERNEL);
269         if (!bl)
270                 return -ENOMEM;
271
272         bl->lp = lp;
273         if (lp->pdata)
274                 bl->pdata = lp->pdata->bl_pdata;
275
276         platform_set_drvdata(pdev, bl);
277
278         ret = lp8788_backlight_configure(bl);
279         if (ret) {
280                 dev_err(lp->dev, "backlight config err: %d\n", ret);
281                 goto err_dev;
282         }
283
284         ret = lp8788_backlight_register(bl);
285         if (ret) {
286                 dev_err(lp->dev, "register backlight err: %d\n", ret);
287                 goto err_dev;
288         }
289
290         ret = sysfs_create_group(&pdev->dev.kobj, &lp8788_attr_group);
291         if (ret) {
292                 dev_err(lp->dev, "register sysfs err: %d\n", ret);
293                 goto err_sysfs;
294         }
295
296         backlight_update_status(bl->bl_dev);
297
298         return 0;
299
300 err_sysfs:
301         lp8788_backlight_unregister(bl);
302 err_dev:
303         return ret;
304 }
305
306 static int lp8788_backlight_remove(struct platform_device *pdev)
307 {
308         struct lp8788_bl *bl = platform_get_drvdata(pdev);
309         struct backlight_device *bl_dev = bl->bl_dev;
310
311         bl_dev->props.brightness = 0;
312         backlight_update_status(bl_dev);
313         sysfs_remove_group(&pdev->dev.kobj, &lp8788_attr_group);
314         lp8788_backlight_unregister(bl);
315         platform_set_drvdata(pdev, NULL);
316
317         return 0;
318 }
319
320 static struct platform_driver lp8788_bl_driver = {
321         .probe = lp8788_backlight_probe,
322         .remove = lp8788_backlight_remove,
323         .driver = {
324                 .name = LP8788_DEV_BACKLIGHT,
325                 .owner = THIS_MODULE,
326         },
327 };
328 module_platform_driver(lp8788_bl_driver);
329
330 MODULE_DESCRIPTION("Texas Instruments LP8788 Backlight Driver");
331 MODULE_AUTHOR("Milo Kim");
332 MODULE_LICENSE("GPL");
333 MODULE_ALIAS("platform:lp8788-backlight");