/* * Backlight driver for Maxim MAX8925 * * Copyright (C) 2009 Marvell International Ltd. * Haojian Zhuang <haojian.zhuang@marvell.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/init.h> #include <linux/kernel.h> #include <linux/platform_device.h> #include <linux/fb.h> #include <linux/i2c.h> #include <linux/backlight.h> #include <linux/mfd/max8925.h> #include <linux/slab.h> #define MAX_BRIGHTNESS (0xff) #define MIN_BRIGHTNESS (0) #define LWX_FREQ(x) (((x - 601) / 100) & 0x7) struct max8925_backlight_data { struct max8925_chip *chip; int current_brightness; }; static int max8925_backlight_set(struct backlight_device *bl, int brightness) { struct max8925_backlight_data *data = bl_get_data(bl); struct max8925_chip *chip = data->chip; unsigned char value; int ret; if (brightness > MAX_BRIGHTNESS) value = MAX_BRIGHTNESS; else value = brightness; ret = max8925_reg_write(chip->i2c, MAX8925_WLED_CNTL, value); if (ret < 0) goto out; if (!data->current_brightness && brightness) /* enable WLED output */ ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 1, 1); else if (!brightness) /* disable WLED output */ ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 1, 0); if (ret < 0) goto out; dev_dbg(chip->dev, "set brightness %d\n", value); data->current_brightness = value; return 0; out: dev_dbg(chip->dev, "set brightness %d failure with return value:%d\n", value, ret); return ret; } static int max8925_backlight_update_status(struct backlight_device *bl) { int brightness = bl->props.brightness; if (bl->props.power != FB_BLANK_UNBLANK) brightness = 0; if (bl->props.fb_blank != FB_BLANK_UNBLANK) brightness = 0; if (bl->props.state & BL_CORE_SUSPENDED) brightness = 0; return max8925_backlight_set(bl, brightness); } static int max8925_backlight_get_brightness(struct backlight_device *bl) { struct max8925_backlight_data *data = bl_get_data(bl); struct max8925_chip *chip = data->chip; int ret; ret = max8925_reg_read(chip->i2c, MAX8925_WLED_CNTL); if (ret < 0) return -EINVAL; data->current_brightness = ret; dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness); return ret; } static struct backlight_ops max8925_backlight_ops = { .options = BL_CORE_SUSPENDRESUME, .update_status = max8925_backlight_update_status, .get_brightness = max8925_backlight_get_brightness, }; static int __devinit max8925_backlight_probe(struct platform_device *pdev) { struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent); struct max8925_platform_data *max8925_pdata; struct max8925_backlight_pdata *pdata = NULL; struct max8925_backlight_data *data; struct backlight_device *bl; struct backlight_properties props; struct resource *res; char name[MAX8925_NAME_SIZE]; unsigned char value; int ret; res = platform_get_resource(pdev, IORESOURCE_IO, 0); if (res == NULL) { dev_err(&pdev->dev, "No I/O resource!\n"); return -EINVAL; } if (pdev->dev.parent->platform_data) { max8925_pdata = pdev->dev.parent->platform_data; pdata = max8925_pdata->backlight; } if (!pdata) { dev_err(&pdev->dev, "platform data isn't assigned to " "backlight\n"); return -EINVAL; } data = kzalloc(sizeof(struct max8925_backlight_data), GFP_KERNEL); if (data == NULL) return -ENOMEM; strncpy(name, res->name, MAX8925_NAME_SIZE); data->chip = chip; data->current_brightness = 0; memset(&props, 0, sizeof(struct backlight_properties)); props.max_brightness = MAX_BRIGHTNESS; bl = backlight_device_register(name, &pdev->dev, data, &max8925_backlight_ops, &props); if (IS_ERR(bl)) { dev_err(&pdev->dev, "failed to register backlight\n"); kfree(data); return PTR_ERR(bl); } bl->props.brightness = MAX_BRIGHTNESS; platform_set_drvdata(pdev, bl); value = 0; if (pdata->lxw_scl) value |= (1 << 7); if (pdata->lxw_freq) value |= (LWX_FREQ(pdata->lxw_freq) << 4); if (pdata->dual_string) value |= (1 << 1); ret = max8925_set_bits(chip->i2c, MAX8925_WLED_MODE_CNTL, 0xfe, value); if (ret < 0) goto out; backlight_update_status(bl); return 0; out: backlight_device_unregister(bl); kfree(data); return ret; } static int __devexit max8925_backlight_remove(struct platform_device *pdev) { struct backlight_device *bl = platform_get_drvdata(pdev); struct max8925_backlight_data *data = bl_get_data(bl); backlight_device_unregister(bl); kfree(data); return 0; } static struct platform_driver max8925_backlight_driver = { .driver = { .name = "max8925-backlight", .owner = THIS_MODULE, }, .probe = max8925_backlight_probe, .remove = __devexit_p(max8925_backlight_remove), }; static int __init max8925_backlight_init(void) { return platform_driver_register(&max8925_backlight_driver); } module_init(max8925_backlight_init); static void __exit max8925_backlight_exit(void) { platform_driver_unregister(&max8925_backlight_driver); }; module_exit(max8925_backlight_exit); MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925"); MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:max8925-backlight");