2 * Backlight driver for Maxim MAX8925
4 * Copyright (C) 2009 Marvell International Ltd.
5 * Haojian Zhuang <haojian.zhuang@marvell.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/platform_device.h>
16 #include <linux/i2c.h>
17 #include <linux/backlight.h>
18 #include <linux/mfd/max8925.h>
19 #include <linux/slab.h>
20 #include <linux/module.h>
22 #define MAX_BRIGHTNESS (0xff)
23 #define MIN_BRIGHTNESS (0)
25 #define LWX_FREQ(x) (((x - 601) / 100) & 0x7)
27 struct max8925_backlight_data {
28 struct max8925_chip *chip;
30 int current_brightness;
35 static int max8925_backlight_set(struct backlight_device *bl, int brightness)
37 struct max8925_backlight_data *data = bl_get_data(bl);
38 struct max8925_chip *chip = data->chip;
42 if (brightness > MAX_BRIGHTNESS)
43 value = MAX_BRIGHTNESS;
47 ret = max8925_reg_write(chip->i2c, data->reg_cntl, value);
51 if (!data->current_brightness && brightness)
52 /* enable WLED output */
53 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 1);
55 /* disable WLED output */
56 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 0);
59 dev_dbg(chip->dev, "set brightness %d\n", value);
60 data->current_brightness = value;
63 dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n",
68 static int max8925_backlight_update_status(struct backlight_device *bl)
70 int brightness = bl->props.brightness;
72 if (bl->props.power != FB_BLANK_UNBLANK)
75 if (bl->props.fb_blank != FB_BLANK_UNBLANK)
78 if (bl->props.state & BL_CORE_SUSPENDED)
81 return max8925_backlight_set(bl, brightness);
84 static int max8925_backlight_get_brightness(struct backlight_device *bl)
86 struct max8925_backlight_data *data = bl_get_data(bl);
87 struct max8925_chip *chip = data->chip;
90 ret = max8925_reg_read(chip->i2c, data->reg_cntl);
93 data->current_brightness = ret;
94 dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
98 static const struct backlight_ops max8925_backlight_ops = {
99 .options = BL_CORE_SUSPENDRESUME,
100 .update_status = max8925_backlight_update_status,
101 .get_brightness = max8925_backlight_get_brightness,
104 static int __devinit max8925_backlight_probe(struct platform_device *pdev)
106 struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
107 struct max8925_backlight_pdata *pdata = pdev->dev.platform_data;
108 struct max8925_backlight_data *data;
109 struct backlight_device *bl;
110 struct backlight_properties props;
111 struct resource *res;
115 data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data),
120 res = platform_get_resource(pdev, IORESOURCE_REG, 0);
122 dev_err(&pdev->dev, "No REG resource for mode control!\n");
126 data->reg_mode_cntl = res->start;
127 res = platform_get_resource(pdev, IORESOURCE_REG, 1);
129 dev_err(&pdev->dev, "No REG resource for control!\n");
133 data->reg_cntl = res->start;
136 data->current_brightness = 0;
138 memset(&props, 0, sizeof(struct backlight_properties));
139 props.type = BACKLIGHT_RAW;
140 props.max_brightness = MAX_BRIGHTNESS;
141 bl = backlight_device_register("max8925-backlight", &pdev->dev, data,
142 &max8925_backlight_ops, &props);
144 dev_err(&pdev->dev, "failed to register backlight\n");
148 bl->props.brightness = MAX_BRIGHTNESS;
150 platform_set_drvdata(pdev, bl);
157 value |= (LWX_FREQ(pdata->lxw_freq) << 4);
158 if (pdata->dual_string)
161 ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value);
165 backlight_update_status(bl);
168 backlight_device_unregister(bl);
170 devm_kfree(&pdev->dev, data);
174 static int __devexit max8925_backlight_remove(struct platform_device *pdev)
176 struct backlight_device *bl = platform_get_drvdata(pdev);
178 backlight_device_unregister(bl);
182 static struct platform_driver max8925_backlight_driver = {
184 .name = "max8925-backlight",
185 .owner = THIS_MODULE,
187 .probe = max8925_backlight_probe,
188 .remove = __devexit_p(max8925_backlight_remove),
191 module_platform_driver(max8925_backlight_driver);
193 MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
194 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
195 MODULE_LICENSE("GPL");
196 MODULE_ALIAS("platform:max8925-backlight");