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