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 | */ |
36 | int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit) |
37 | { |
38 | struct pcf50633_bl *pcf_bl = platform_get_drvdata(pdev: pcf->bl_pdev); |
39 | |
40 | if (!pcf_bl) |
41 | return -ENODEV; |
42 | |
43 | pcf_bl->brightness_limit = limit & 0x3f; |
44 | backlight_update_status(bd: pcf_bl->bl); |
45 | |
46 | return 0; |
47 | } |
48 | |
49 | static int pcf50633_bl_update_status(struct backlight_device *bl) |
50 | { |
51 | struct pcf50633_bl *pcf_bl = bl_get_data(bl_dev: 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: pcf_bl->pcf, PCF50633_REG_LEDOUT, |
69 | val: new_brightness); |
70 | if (!pcf_bl->brightness) |
71 | pcf50633_reg_write(pcf: pcf_bl->pcf, PCF50633_REG_LEDENA, val: 1); |
72 | } else { |
73 | pcf50633_reg_write(pcf: pcf_bl->pcf, PCF50633_REG_LEDENA, val: 0); |
74 | } |
75 | |
76 | pcf_bl->brightness = new_brightness; |
77 | |
78 | return 0; |
79 | } |
80 | |
81 | static int pcf50633_bl_get_brightness(struct backlight_device *bl) |
82 | { |
83 | struct pcf50633_bl *pcf_bl = bl_get_data(bl_dev: 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 | |
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(dev: parent); |
99 | struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data; |
100 | struct backlight_properties bl_props; |
101 | |
102 | pcf_bl = devm_kzalloc(dev: &pdev->dev, size: 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(dev: pdev->dev.parent); |
120 | |
121 | pcf_bl->bl = devm_backlight_device_register(dev: &pdev->dev, name: pdev->name, |
122 | parent: &pdev->dev, devdata: pcf_bl, |
123 | ops: &pcf50633_bl_ops, props: &bl_props); |
124 | |
125 | if (IS_ERR(ptr: pcf_bl->bl)) |
126 | return PTR_ERR(ptr: pcf_bl->bl); |
127 | |
128 | platform_set_drvdata(pdev, data: pcf_bl); |
129 | |
130 | pcf50633_reg_write(pcf: pcf_bl->pcf, PCF50633_REG_LEDDIM, val: 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(bd: 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 | |