Linux-libre 5.3.12-gnu
[librecmc/linux-libre.git] / drivers / video / backlight / lp8788_bl.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * TI LP8788 MFD - backlight driver
4  *
5  * Copyright 2012 Texas Instruments
6  *
7  * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
8  */
9
10 #include <linux/backlight.h>
11 #include <linux/err.h>
12 #include <linux/mfd/lp8788.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/pwm.h>
16 #include <linux/slab.h>
17
18 /* Register address */
19 #define LP8788_BL_CONFIG                0x96
20 #define LP8788_BL_EN                    BIT(0)
21 #define LP8788_BL_PWM_INPUT_EN          BIT(5)
22 #define LP8788_BL_FULLSCALE_SHIFT       2
23 #define LP8788_BL_DIM_MODE_SHIFT        1
24 #define LP8788_BL_PWM_POLARITY_SHIFT    6
25
26 #define LP8788_BL_BRIGHTNESS            0x97
27
28 #define LP8788_BL_RAMP                  0x98
29 #define LP8788_BL_RAMP_RISE_SHIFT       4
30
31 #define MAX_BRIGHTNESS                  127
32 #define DEFAULT_BL_NAME                 "lcd-backlight"
33
34 struct lp8788_bl_config {
35         enum lp8788_bl_ctrl_mode bl_mode;
36         enum lp8788_bl_dim_mode dim_mode;
37         enum lp8788_bl_full_scale_current full_scale;
38         enum lp8788_bl_ramp_step rise_time;
39         enum lp8788_bl_ramp_step fall_time;
40         enum pwm_polarity pwm_pol;
41 };
42
43 struct lp8788_bl {
44         struct lp8788 *lp;
45         struct backlight_device *bl_dev;
46         struct lp8788_backlight_platform_data *pdata;
47         enum lp8788_bl_ctrl_mode mode;
48         struct pwm_device *pwm;
49 };
50
51 static struct lp8788_bl_config default_bl_config = {
52         .bl_mode    = LP8788_BL_REGISTER_ONLY,
53         .dim_mode   = LP8788_DIM_EXPONENTIAL,
54         .full_scale = LP8788_FULLSCALE_1900uA,
55         .rise_time  = LP8788_RAMP_8192us,
56         .fall_time  = LP8788_RAMP_8192us,
57         .pwm_pol    = PWM_POLARITY_NORMAL,
58 };
59
60 static inline bool is_brightness_ctrl_by_pwm(enum lp8788_bl_ctrl_mode mode)
61 {
62         return mode == LP8788_BL_COMB_PWM_BASED;
63 }
64
65 static inline bool is_brightness_ctrl_by_register(enum lp8788_bl_ctrl_mode mode)
66 {
67         return mode == LP8788_BL_REGISTER_ONLY ||
68                 mode == LP8788_BL_COMB_REGISTER_BASED;
69 }
70
71 static int lp8788_backlight_configure(struct lp8788_bl *bl)
72 {
73         struct lp8788_backlight_platform_data *pdata = bl->pdata;
74         struct lp8788_bl_config *cfg = &default_bl_config;
75         int ret;
76         u8 val;
77
78         /*
79          * Update chip configuration if platform data exists,
80          * otherwise use the default settings.
81          */
82         if (pdata) {
83                 cfg->bl_mode    = pdata->bl_mode;
84                 cfg->dim_mode   = pdata->dim_mode;
85                 cfg->full_scale = pdata->full_scale;
86                 cfg->rise_time  = pdata->rise_time;
87                 cfg->fall_time  = pdata->fall_time;
88                 cfg->pwm_pol    = pdata->pwm_pol;
89         }
90
91         /* Brightness ramp up/down */
92         val = (cfg->rise_time << LP8788_BL_RAMP_RISE_SHIFT) | cfg->fall_time;
93         ret = lp8788_write_byte(bl->lp, LP8788_BL_RAMP, val);
94         if (ret)
95                 return ret;
96
97         /* Fullscale current setting */
98         val = (cfg->full_scale << LP8788_BL_FULLSCALE_SHIFT) |
99                 (cfg->dim_mode << LP8788_BL_DIM_MODE_SHIFT);
100
101         /* Brightness control mode */
102         switch (cfg->bl_mode) {
103         case LP8788_BL_REGISTER_ONLY:
104                 val |= LP8788_BL_EN;
105                 break;
106         case LP8788_BL_COMB_PWM_BASED:
107         case LP8788_BL_COMB_REGISTER_BASED:
108                 val |= LP8788_BL_EN | LP8788_BL_PWM_INPUT_EN |
109                         (cfg->pwm_pol << LP8788_BL_PWM_POLARITY_SHIFT);
110                 break;
111         default:
112                 dev_err(bl->lp->dev, "invalid mode: %d\n", cfg->bl_mode);
113                 return -EINVAL;
114         }
115
116         bl->mode = cfg->bl_mode;
117
118         return lp8788_write_byte(bl->lp, LP8788_BL_CONFIG, val);
119 }
120
121 static void lp8788_pwm_ctrl(struct lp8788_bl *bl, int br, int max_br)
122 {
123         unsigned int period;
124         unsigned int duty;
125         struct device *dev;
126         struct pwm_device *pwm;
127
128         if (!bl->pdata)
129                 return;
130
131         period = bl->pdata->period_ns;
132         duty = br * period / max_br;
133         dev = bl->lp->dev;
134
135         /* request PWM device with the consumer name */
136         if (!bl->pwm) {
137                 pwm = devm_pwm_get(dev, LP8788_DEV_BACKLIGHT);
138                 if (IS_ERR(pwm)) {
139                         dev_err(dev, "can not get PWM device\n");
140                         return;
141                 }
142
143                 bl->pwm = pwm;
144
145                 /*
146                  * FIXME: pwm_apply_args() should be removed when switching to
147                  * the atomic PWM API.
148                  */
149                 pwm_apply_args(pwm);
150         }
151
152         pwm_config(bl->pwm, duty, period);
153         if (duty)
154                 pwm_enable(bl->pwm);
155         else
156                 pwm_disable(bl->pwm);
157 }
158
159 static int lp8788_bl_update_status(struct backlight_device *bl_dev)
160 {
161         struct lp8788_bl *bl = bl_get_data(bl_dev);
162         enum lp8788_bl_ctrl_mode mode = bl->mode;
163
164         if (bl_dev->props.state & BL_CORE_SUSPENDED)
165                 bl_dev->props.brightness = 0;
166
167         if (is_brightness_ctrl_by_pwm(mode)) {
168                 int brt = bl_dev->props.brightness;
169                 int max = bl_dev->props.max_brightness;
170
171                 lp8788_pwm_ctrl(bl, brt, max);
172         } else if (is_brightness_ctrl_by_register(mode)) {
173                 u8 brt = bl_dev->props.brightness;
174
175                 lp8788_write_byte(bl->lp, LP8788_BL_BRIGHTNESS, brt);
176         }
177
178         return 0;
179 }
180
181 static const struct backlight_ops lp8788_bl_ops = {
182         .options = BL_CORE_SUSPENDRESUME,
183         .update_status = lp8788_bl_update_status,
184 };
185
186 static int lp8788_backlight_register(struct lp8788_bl *bl)
187 {
188         struct backlight_device *bl_dev;
189         struct backlight_properties props;
190         struct lp8788_backlight_platform_data *pdata = bl->pdata;
191         int init_brt;
192         char *name;
193
194         props.type = BACKLIGHT_PLATFORM;
195         props.max_brightness = MAX_BRIGHTNESS;
196
197         /* Initial brightness */
198         if (pdata)
199                 init_brt = min_t(int, pdata->initial_brightness,
200                                 props.max_brightness);
201         else
202                 init_brt = 0;
203
204         props.brightness = init_brt;
205
206         /* Backlight device name */
207         if (!pdata || !pdata->name)
208                 name = DEFAULT_BL_NAME;
209         else
210                 name = pdata->name;
211
212         bl_dev = backlight_device_register(name, bl->lp->dev, bl,
213                                        &lp8788_bl_ops, &props);
214         if (IS_ERR(bl_dev))
215                 return PTR_ERR(bl_dev);
216
217         bl->bl_dev = bl_dev;
218
219         return 0;
220 }
221
222 static void lp8788_backlight_unregister(struct lp8788_bl *bl)
223 {
224         struct backlight_device *bl_dev = bl->bl_dev;
225
226         backlight_device_unregister(bl_dev);
227 }
228
229 static ssize_t lp8788_get_bl_ctl_mode(struct device *dev,
230                                      struct device_attribute *attr, char *buf)
231 {
232         struct lp8788_bl *bl = dev_get_drvdata(dev);
233         enum lp8788_bl_ctrl_mode mode = bl->mode;
234         char *strmode;
235
236         if (is_brightness_ctrl_by_pwm(mode))
237                 strmode = "PWM based";
238         else if (is_brightness_ctrl_by_register(mode))
239                 strmode = "Register based";
240         else
241                 strmode = "Invalid mode";
242
243         return scnprintf(buf, PAGE_SIZE, "%s\n", strmode);
244 }
245
246 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp8788_get_bl_ctl_mode, NULL);
247
248 static struct attribute *lp8788_attributes[] = {
249         &dev_attr_bl_ctl_mode.attr,
250         NULL,
251 };
252
253 static const struct attribute_group lp8788_attr_group = {
254         .attrs = lp8788_attributes,
255 };
256
257 static int lp8788_backlight_probe(struct platform_device *pdev)
258 {
259         struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
260         struct lp8788_bl *bl;
261         int ret;
262
263         bl = devm_kzalloc(lp->dev, sizeof(struct lp8788_bl), GFP_KERNEL);
264         if (!bl)
265                 return -ENOMEM;
266
267         bl->lp = lp;
268         if (lp->pdata)
269                 bl->pdata = lp->pdata->bl_pdata;
270
271         platform_set_drvdata(pdev, bl);
272
273         ret = lp8788_backlight_configure(bl);
274         if (ret) {
275                 dev_err(lp->dev, "backlight config err: %d\n", ret);
276                 goto err_dev;
277         }
278
279         ret = lp8788_backlight_register(bl);
280         if (ret) {
281                 dev_err(lp->dev, "register backlight err: %d\n", ret);
282                 goto err_dev;
283         }
284
285         ret = sysfs_create_group(&pdev->dev.kobj, &lp8788_attr_group);
286         if (ret) {
287                 dev_err(lp->dev, "register sysfs err: %d\n", ret);
288                 goto err_sysfs;
289         }
290
291         backlight_update_status(bl->bl_dev);
292
293         return 0;
294
295 err_sysfs:
296         lp8788_backlight_unregister(bl);
297 err_dev:
298         return ret;
299 }
300
301 static int lp8788_backlight_remove(struct platform_device *pdev)
302 {
303         struct lp8788_bl *bl = platform_get_drvdata(pdev);
304         struct backlight_device *bl_dev = bl->bl_dev;
305
306         bl_dev->props.brightness = 0;
307         backlight_update_status(bl_dev);
308         sysfs_remove_group(&pdev->dev.kobj, &lp8788_attr_group);
309         lp8788_backlight_unregister(bl);
310
311         return 0;
312 }
313
314 static struct platform_driver lp8788_bl_driver = {
315         .probe = lp8788_backlight_probe,
316         .remove = lp8788_backlight_remove,
317         .driver = {
318                 .name = LP8788_DEV_BACKLIGHT,
319         },
320 };
321 module_platform_driver(lp8788_bl_driver);
322
323 MODULE_DESCRIPTION("Texas Instruments LP8788 Backlight Driver");
324 MODULE_AUTHOR("Milo Kim");
325 MODULE_LICENSE("GPL");
326 MODULE_ALIAS("platform:lp8788-backlight");