diff options
Diffstat (limited to 'drivers/video/backlight/max8925_bl.c')
| -rw-r--r-- | drivers/video/backlight/max8925_bl.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c new file mode 100644 index 00000000000..c267069a52a --- /dev/null +++ b/drivers/video/backlight/max8925_bl.c @@ -0,0 +1,200 @@ +/* + * 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> + +#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 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; + + bl = backlight_device_register(name, &pdev->dev, data, + &max8925_backlight_ops); + if (IS_ERR(bl)) { + dev_err(&pdev->dev, "failed to register backlight\n"); + kfree(data); + return PTR_ERR(bl); + } + bl->props.max_brightness = MAX_BRIGHTNESS; + 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: + 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"); |