2 * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
3 * PCF50633 backlight device driver
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
10 * You should have received a copy of the GNU General Public License along
11 * with this program; if not, write to the Free Software Foundation, Inc.,
12 * 675 Mass Ave, Cambridge, MA 02139, USA.
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/platform_device.h>
21 #include <linux/backlight.h>
24 #include <linux/mfd/pcf50633/core.h>
25 #include <linux/mfd/pcf50633/backlight.h>
29 struct backlight_device *bl;
31 unsigned int brightness;
32 unsigned int brightness_limit;
36 * pcf50633_bl_set_brightness_limit
38 * Update the brightness limit for the pc50633 backlight. The actual brightness
39 * will not go above the limit. This is useful to limit power drain for example
42 * @dev: Pointer to a pcf50633 device
43 * @limit: The brightness limit. Valid values are 0-63
45 int pcf50633_bl_set_brightness_limit(struct pcf50633 *pcf, unsigned int limit)
47 struct pcf50633_bl *pcf_bl = platform_get_drvdata(pcf->bl_pdev);
52 pcf_bl->brightness_limit = limit & 0x3f;
53 backlight_update_status(pcf_bl->bl);
58 static int pcf50633_bl_update_status(struct backlight_device *bl)
60 struct pcf50633_bl *pcf_bl = bl_get_data(bl);
61 unsigned int new_brightness;
64 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK) ||
65 bl->props.power != FB_BLANK_UNBLANK)
67 else if (bl->props.brightness < pcf_bl->brightness_limit)
68 new_brightness = bl->props.brightness;
70 new_brightness = pcf_bl->brightness_limit;
73 if (pcf_bl->brightness == new_brightness)
77 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDOUT,
79 if (!pcf_bl->brightness)
80 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 1);
82 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDENA, 0);
85 pcf_bl->brightness = new_brightness;
90 static int pcf50633_bl_get_brightness(struct backlight_device *bl)
92 struct pcf50633_bl *pcf_bl = bl_get_data(bl);
93 return pcf_bl->brightness;
96 static const struct backlight_ops pcf50633_bl_ops = {
97 .get_brightness = pcf50633_bl_get_brightness,
98 .update_status = pcf50633_bl_update_status,
99 .options = BL_CORE_SUSPENDRESUME,
102 static int pcf50633_bl_probe(struct platform_device *pdev)
104 struct pcf50633_bl *pcf_bl;
105 struct device *parent = pdev->dev.parent;
106 struct pcf50633_platform_data *pcf50633_data = parent->platform_data;
107 struct pcf50633_bl_platform_data *pdata = pcf50633_data->backlight_data;
108 struct backlight_properties bl_props;
110 pcf_bl = devm_kzalloc(&pdev->dev, sizeof(*pcf_bl), GFP_KERNEL);
114 memset(&bl_props, 0, sizeof(bl_props));
115 bl_props.type = BACKLIGHT_RAW;
116 bl_props.max_brightness = 0x3f;
117 bl_props.power = FB_BLANK_UNBLANK;
120 bl_props.brightness = pdata->default_brightness;
121 pcf_bl->brightness_limit = pdata->default_brightness_limit;
123 bl_props.brightness = 0x3f;
124 pcf_bl->brightness_limit = 0x3f;
127 pcf_bl->pcf = dev_to_pcf50633(pdev->dev.parent);
129 pcf_bl->bl = backlight_device_register(pdev->name, &pdev->dev, pcf_bl,
130 &pcf50633_bl_ops, &bl_props);
132 if (IS_ERR(pcf_bl->bl))
133 return PTR_ERR(pcf_bl->bl);
135 platform_set_drvdata(pdev, pcf_bl);
137 pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time);
140 * Should be different from bl_props.brightness, so we do not exit
141 * update_status early the first time it's called
143 pcf_bl->brightness = pcf_bl->bl->props.brightness + 1;
145 backlight_update_status(pcf_bl->bl);
150 static int pcf50633_bl_remove(struct platform_device *pdev)
152 struct pcf50633_bl *pcf_bl = platform_get_drvdata(pdev);
154 backlight_device_unregister(pcf_bl->bl);
156 platform_set_drvdata(pdev, NULL);
161 static struct platform_driver pcf50633_bl_driver = {
162 .probe = pcf50633_bl_probe,
163 .remove = pcf50633_bl_remove,
165 .name = "pcf50633-backlight",
169 module_platform_driver(pcf50633_bl_driver);
171 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
172 MODULE_DESCRIPTION("PCF50633 backlight driver");
173 MODULE_LICENSE("GPL");
174 MODULE_ALIAS("platform:pcf50633-backlight");