1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
4 * PCF50633 backlight device driver
5 */
6
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/platform_device.h>
11
12 #include <linux/backlight.h>
13 #include <linux/fb.h>
14
15 #include <linux/mfd/pcf50633/core.h>
16 #include <linux/mfd/pcf50633/backlight.h>
17
18 struct pcf50633_bl {
19 struct pcf50633 *pcf;
20 struct backlight_device *bl;
21
22 unsigned int brightness;
23 unsigned int brightness_limit;
24 };
25
26 /*
27 * pcf50633_bl_set_brightness_limit
28 *
29 * Update the brightness limit for the pc50633 backlight. The actual brightness
30 * will not go above the limit. This is useful to limit power drain for example
31 * on low battery.
32 *
33 * @dev: Pointer to a pcf50633 device
34 * @limit: The brightness limit. Valid values are 0-63
35 */
pcf50633_bl_set_brightness_limit(struct pcf50633 * pcf,unsigned int limit)36 int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit)
37 {
38 struct pcf50633_bl *pcf_bl = platform_get_drvdata(pcf->bl_pdev);
39
40 if (!pcf_bl)
41 return -ENODEV;
42
43 pcf_bl->brightness_limit = limit & 0x3f;
44 backlight_update_status(pcf_bl->bl);
45
46 return 0;
47 }
48
pcf50633_bl_update_status(struct backlight_device * bl)49 static int pcf50633_bl_update_status(struct backlight_device *bl)
50 {
51 struct pcf50633_bl *pcf_bl = bl_get_data(bl);
52 unsigned int new_brightness;
53
54
55 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK) ||
56 bl->props.power != FB_BLANK_UNBLANK)
57 new_brightness = 0;
58 else if (bl->props.brightness < pcf_bl->brightness_limit)
59 new_brightness = bl->props.brightness;
60 else
61 new_brightness = pcf_bl->brightness_limit;
62
63
64 if (pcf_bl->brightness == new_brightness)
65 return 0;
66
67 if (new_brightness) {
68 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDOUT,
69 new_brightness);
70 if (!pcf_bl->brightness)
71 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 1);
72 } else {
73 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 0);
74 }
75
76 pcf_bl->brightness = new_brightness;
77
78 return 0;
79 }
80
pcf50633_bl_get_brightness(struct backlight_device * bl)81 static int pcf50633_bl_get_brightness(struct backlight_device *bl)
82 {
83 struct pcf50633_bl *pcf_bl = bl_get_data(bl);
84
85 return pcf_bl->brightness;
86 }
87
88 static const struct backlight_ops pcf50633_bl_ops = {
89 .get_brightness = pcf50633_bl_get_brightness,
90 .update_status = pcf50633_bl_update_status,
91 .options = BL_CORE_SUSPENDRESUME,
92 };
93
pcf50633_bl_probe(struct platform_device * pdev)94 static int pcf50633_bl_probe(struct platform_device *pdev)
95 {
96 struct pcf50633_bl *pcf_bl;
97 struct device *parent = pdev->dev.parent;
98 struct pcf50633_platform_data *pcf50633_data = dev_get_platdata(parent);
99 struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data;
100 struct backlight_properties bl_props;
101
102 pcf_bl = devm_kzalloc(&pdev->dev, sizeof(*pcf_bl), GFP_KERNEL);
103 if (!pcf_bl)
104 return -ENOMEM;
105
106 memset(&bl_props, 0, sizeof(bl_props));
107 bl_props.type = BACKLIGHT_RAW;
108 bl_props.max_brightness = 0x3f;
109 bl_props.power = FB_BLANK_UNBLANK;
110
111 if (pdata) {
112 bl_props.brightness = pdata->default_brightness;
113 pcf_bl->brightness_limit = pdata->default_brightness_limit;
114 } else {
115 bl_props.brightness = 0x3f;
116 pcf_bl->brightness_limit = 0x3f;
117 }
118
119 pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent);
120
121 pcf_bl->bl = devm_backlight_device_register(&pdev->dev, pdev->name,
122 &pdev->dev, pcf_bl,
123 &pcf50633_bl_ops, &bl_props);
124
125 if (IS_ERR(pcf_bl->bl))
126 return PTR_ERR(pcf_bl->bl);
127
128 platform_set_drvdata(pdev, pcf_bl);
129
130 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time);
131
132 /*
133 * Should be different from bl_props.brightness, so we do not exit
134 * update_status early the first time it's called
135 */
136 pcf_bl->brightness = pcf_bl->bl->props.brightness + 1;
137
138 backlight_update_status(pcf_bl->bl);
139
140 return 0;
141 }
142
143 static struct platform_driver pcf50633_bl_driver = {
144 .probe = pcf50633_bl_probe,
145 .driver = {
146 .name = "pcf50633-backlight",
147 },
148 };
149
150 module_platform_driver(pcf50633_bl_driver);
151
152 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
153 MODULE_DESCRIPTION("PCF50633 backlight driver");
154 MODULE_LICENSE("GPL");
155 MODULE_ALIAS("platform:pcf50633-backlight");
156
