]> git.openfabrics.org - ~shefty/rdma-dev.git/blob - drivers/video/backlight/pwm_bl.c
backlight: convert pwm_bl to dev_pm_ops
[~shefty/rdma-dev.git] / drivers / video / backlight / pwm_bl.c
1 /*
2  * linux/drivers/video/backlight/pwm_bl.c
3  *
4  * simple PWM based backlight control, board code has to setup
5  * 1) pin configuration so PWM waveforms can output
6  * 2) platform_data being correctly configured
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 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/init.h>
16 #include <linux/platform_device.h>
17 #include <linux/fb.h>
18 #include <linux/backlight.h>
19 #include <linux/err.h>
20 #include <linux/pwm.h>
21 #include <linux/pwm_backlight.h>
22 #include <linux/slab.h>
23
24 struct pwm_bl_data {
25         struct pwm_device       *pwm;
26         struct device           *dev;
27         unsigned int            period;
28         unsigned int            lth_brightness;
29         int                     (*notify)(struct device *,
30                                           int brightness);
31         void                    (*notify_after)(struct device *,
32                                         int brightness);
33         int                     (*check_fb)(struct device *, struct fb_info *);
34 };
35
36 static int pwm_backlight_update_status(struct backlight_device *bl)
37 {
38         struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
39         int brightness = bl->props.brightness;
40         int max = bl->props.max_brightness;
41
42         if (bl->props.power != FB_BLANK_UNBLANK)
43                 brightness = 0;
44
45         if (bl->props.fb_blank != FB_BLANK_UNBLANK)
46                 brightness = 0;
47
48         if (pb->notify)
49                 brightness = pb->notify(pb->dev, brightness);
50
51         if (brightness == 0) {
52                 pwm_config(pb->pwm, 0, pb->period);
53                 pwm_disable(pb->pwm);
54         } else {
55                 brightness = pb->lth_brightness +
56                         (brightness * (pb->period - pb->lth_brightness) / max);
57                 pwm_config(pb->pwm, brightness, pb->period);
58                 pwm_enable(pb->pwm);
59         }
60
61         if (pb->notify_after)
62                 pb->notify_after(pb->dev, brightness);
63
64         return 0;
65 }
66
67 static int pwm_backlight_get_brightness(struct backlight_device *bl)
68 {
69         return bl->props.brightness;
70 }
71
72 static int pwm_backlight_check_fb(struct backlight_device *bl,
73                                   struct fb_info *info)
74 {
75         struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
76
77         return !pb->check_fb || pb->check_fb(pb->dev, info);
78 }
79
80 static const struct backlight_ops pwm_backlight_ops = {
81         .update_status  = pwm_backlight_update_status,
82         .get_brightness = pwm_backlight_get_brightness,
83         .check_fb       = pwm_backlight_check_fb,
84 };
85
86 static int pwm_backlight_probe(struct platform_device *pdev)
87 {
88         struct backlight_properties props;
89         struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
90         struct backlight_device *bl;
91         struct pwm_bl_data *pb;
92         int ret;
93
94         if (!data) {
95                 dev_err(&pdev->dev, "failed to find platform data\n");
96                 return -EINVAL;
97         }
98
99         if (data->init) {
100                 ret = data->init(&pdev->dev);
101                 if (ret < 0)
102                         return ret;
103         }
104
105         pb = kzalloc(sizeof(*pb), GFP_KERNEL);
106         if (!pb) {
107                 dev_err(&pdev->dev, "no memory for state\n");
108                 ret = -ENOMEM;
109                 goto err_alloc;
110         }
111
112         pb->period = data->pwm_period_ns;
113         pb->notify = data->notify;
114         pb->notify_after = data->notify_after;
115         pb->check_fb = data->check_fb;
116         pb->lth_brightness = data->lth_brightness *
117                 (data->pwm_period_ns / data->max_brightness);
118         pb->dev = &pdev->dev;
119
120         pb->pwm = pwm_request(data->pwm_id, "backlight");
121         if (IS_ERR(pb->pwm)) {
122                 dev_err(&pdev->dev, "unable to request PWM for backlight\n");
123                 ret = PTR_ERR(pb->pwm);
124                 goto err_pwm;
125         } else
126                 dev_dbg(&pdev->dev, "got pwm for backlight\n");
127
128         memset(&props, 0, sizeof(struct backlight_properties));
129         props.type = BACKLIGHT_RAW;
130         props.max_brightness = data->max_brightness;
131         bl = backlight_device_register(dev_name(&pdev->dev), &pdev->dev, pb,
132                                        &pwm_backlight_ops, &props);
133         if (IS_ERR(bl)) {
134                 dev_err(&pdev->dev, "failed to register backlight\n");
135                 ret = PTR_ERR(bl);
136                 goto err_bl;
137         }
138
139         bl->props.brightness = data->dft_brightness;
140         backlight_update_status(bl);
141
142         platform_set_drvdata(pdev, bl);
143         return 0;
144
145 err_bl:
146         pwm_free(pb->pwm);
147 err_pwm:
148         kfree(pb);
149 err_alloc:
150         if (data->exit)
151                 data->exit(&pdev->dev);
152         return ret;
153 }
154
155 static int pwm_backlight_remove(struct platform_device *pdev)
156 {
157         struct platform_pwm_backlight_data *data = pdev->dev.platform_data;
158         struct backlight_device *bl = platform_get_drvdata(pdev);
159         struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
160
161         backlight_device_unregister(bl);
162         pwm_config(pb->pwm, 0, pb->period);
163         pwm_disable(pb->pwm);
164         pwm_free(pb->pwm);
165         kfree(pb);
166         if (data->exit)
167                 data->exit(&pdev->dev);
168         return 0;
169 }
170
171 #ifdef CONFIG_PM
172 static int pwm_backlight_suspend(struct device *dev)
173 {
174         struct backlight_device *bl = dev_get_drvdata(dev);
175         struct pwm_bl_data *pb = dev_get_drvdata(&bl->dev);
176
177         if (pb->notify)
178                 pb->notify(pb->dev, 0);
179         pwm_config(pb->pwm, 0, pb->period);
180         pwm_disable(pb->pwm);
181         if (pb->notify_after)
182                 pb->notify_after(pb->dev, 0);
183         return 0;
184 }
185
186 static int pwm_backlight_resume(struct device *dev)
187 {
188         struct backlight_device *bl = dev_get_drvdata(dev);
189
190         backlight_update_status(bl);
191         return 0;
192 }
193
194 static SIMPLE_DEV_PM_OPS(pwm_backlight_pm_ops, pwm_backlight_suspend,
195                          pwm_backlight_resume);
196
197 #endif
198
199 static struct platform_driver pwm_backlight_driver = {
200         .driver         = {
201                 .name   = "pwm-backlight",
202                 .owner  = THIS_MODULE,
203 #ifdef CONFIG_PM
204                 .pm     = &pwm_backlight_pm_ops,
205 #endif
206         },
207         .probe          = pwm_backlight_probe,
208         .remove         = pwm_backlight_remove,
209 };
210
211 module_platform_driver(pwm_backlight_driver);
212
213 MODULE_DESCRIPTION("PWM based Backlight Driver");
214 MODULE_LICENSE("GPL");
215 MODULE_ALIAS("platform:pwm-backlight");
216