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;
33 static int max8925_backlight_set(struct backlight_device *bl, int brightness)
35 struct max8925_backlight_data *data = bl_get_data(bl);
36 struct max8925_chip *chip = data->chip;
40 if (brightness > MAX_BRIGHTNESS)
41 value = MAX_BRIGHTNESS;
45 ret = max8925_reg_write(chip->i2c, MAX8925_WLED_CNTL, value);
49 if (!data->current_brightness && brightness)
50 /* enable WLED output */
51 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 1, 1);
53 /* disable WLED output */
54 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 1, 0);
57 dev_dbg(chip->dev, "set brightness %d\n", value);
58 data->current_brightness = value;
61 dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n",
66 static int max8925_backlight_update_status(struct backlight_device *bl)
68 int brightness = bl->props.brightness;
70 if (bl->props.power != FB_BLANK_UNBLANK)
73 if (bl->props.fb_blank != FB_BLANK_UNBLANK)
76 if (bl->props.state & BL_CORE_SUSPENDED)
79 return max8925_backlight_set(bl, brightness);
82 static int max8925_backlight_get_brightness(struct backlight_device *bl)
84 struct max8925_backlight_data *data = bl_get_data(bl);
85 struct max8925_chip *chip = data->chip;
88 ret = max8925_reg_read(chip->i2c, MAX8925_WLED_CNTL);
91 data->current_brightness = ret;
92 dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness);
96 static const struct backlight_ops max8925_backlight_ops = {
97 .options = BL_CORE_SUSPENDRESUME,
98 .update_status = max8925_backlight_update_status,
99 .get_brightness = max8925_backlight_get_brightness,
102 static int __devinit max8925_backlight_probe(struct platform_device *pdev)
104 struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent);
105 struct max8925_platform_data *max8925_pdata;
106 struct max8925_backlight_pdata *pdata = NULL;
107 struct max8925_backlight_data *data;
108 struct backlight_device *bl;
109 struct backlight_properties props;
110 struct resource *res;
111 char name[MAX8925_NAME_SIZE];
115 res = platform_get_resource(pdev, IORESOURCE_IO, 0);
117 dev_err(&pdev->dev, "No I/O resource!\n");
121 if (pdev->dev.parent->platform_data) {
122 max8925_pdata = pdev->dev.parent->platform_data;
123 pdata = max8925_pdata->backlight;
127 dev_err(&pdev->dev, "platform data isn't assigned to "
132 data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data),
136 strncpy(name, res->name, MAX8925_NAME_SIZE);
138 data->current_brightness = 0;
140 memset(&props, 0, sizeof(struct backlight_properties));
141 props.type = BACKLIGHT_RAW;
142 props.max_brightness = MAX_BRIGHTNESS;
143 bl = backlight_device_register(name, &pdev->dev, data,
144 &max8925_backlight_ops, &props);
146 dev_err(&pdev->dev, "failed to register backlight\n");
149 bl->props.brightness = MAX_BRIGHTNESS;
151 platform_set_drvdata(pdev, bl);
157 value |= (LWX_FREQ(pdata->lxw_freq) << 4);
158 if (pdata->dual_string)
160 ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 0xfe, value);
164 backlight_update_status(bl);
167 backlight_device_unregister(bl);
171 static int __devexit max8925_backlight_remove(struct platform_device *pdev)
173 struct backlight_device *bl = platform_get_drvdata(pdev);
175 backlight_device_unregister(bl);
179 static struct platform_driver max8925_backlight_driver = {
181 .name = "max8925-backlight",
182 .owner = THIS_MODULE,
184 .probe = max8925_backlight_probe,
185 .remove = __devexit_p(max8925_backlight_remove),
188 module_platform_driver(max8925_backlight_driver);
190 MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925");
191 MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
192 MODULE_LICENSE("GPL");
193 MODULE_ALIAS("platform:max8925-backlight");