diff options
Diffstat (limited to 'drivers/video/backlight/max8925_bl.c')
| -rw-r--r-- | drivers/video/backlight/max8925_bl.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c new file mode 100644 index 000000000..f3aa6088f --- /dev/null +++ b/drivers/video/backlight/max8925_bl.c @@ -0,0 +1,211 @@ +/* + * 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> +#include <linux/module.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; + int reg_mode_cntl; + int reg_cntl; +}; + +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, data->reg_cntl, value); + if (ret < 0) + goto out; + + if (!data->current_brightness && brightness) + /* enable WLED output */ + ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 1, 1); + else if (!brightness) + /* disable WLED output */ + ret = max8925_set_bits(chip->i2c, data->reg_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, data->reg_cntl); + if (ret < 0) + return -EINVAL; + data->current_brightness = ret; + dev_dbg(chip->dev, "get brightness %d\n", data->current_brightness); + return ret; +} + +static const struct backlight_ops max8925_backlight_ops = { + .options = BL_CORE_SUSPENDRESUME, + .update_status = max8925_backlight_update_status, + .get_brightness = max8925_backlight_get_brightness, +}; + +static void max8925_backlight_dt_init(struct platform_device *pdev) +{ + struct device_node *nproot = pdev->dev.parent->of_node, *np; + struct max8925_backlight_pdata *pdata; + u32 val; + + if (!nproot || !IS_ENABLED(CONFIG_OF)) + return; + + pdata = devm_kzalloc(&pdev->dev, + sizeof(struct max8925_backlight_pdata), + GFP_KERNEL); + if (!pdata) + return; + + np = of_get_child_by_name(nproot, "backlight"); + if (!np) { + dev_err(&pdev->dev, "failed to find backlight node\n"); + return; + } + + if (!of_property_read_u32(np, "maxim,max8925-dual-string", &val)) + pdata->dual_string = val; + + of_node_put(np); + + pdev->dev.platform_data = pdata; +} + +static int max8925_backlight_probe(struct platform_device *pdev) +{ + struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent); + struct max8925_backlight_pdata *pdata; + struct max8925_backlight_data *data; + struct backlight_device *bl; + struct backlight_properties props; + struct resource *res; + unsigned char value; + int ret = 0; + + data = devm_kzalloc(&pdev->dev, sizeof(struct max8925_backlight_data), + GFP_KERNEL); + if (data == NULL) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_REG, 0); + if (!res) { + dev_err(&pdev->dev, "No REG resource for mode control!\n"); + return -ENXIO; + } + data->reg_mode_cntl = res->start; + res = platform_get_resource(pdev, IORESOURCE_REG, 1); + if (!res) { + dev_err(&pdev->dev, "No REG resource for control!\n"); + return -ENXIO; + } + data->reg_cntl = res->start; + + data->chip = chip; + data->current_brightness = 0; + + memset(&props, 0, sizeof(struct backlight_properties)); + props.type = BACKLIGHT_RAW; + props.max_brightness = MAX_BRIGHTNESS; + bl = devm_backlight_device_register(&pdev->dev, "max8925-backlight", + &pdev->dev, data, + &max8925_backlight_ops, &props); + if (IS_ERR(bl)) { + dev_err(&pdev->dev, "failed to register backlight\n"); + return PTR_ERR(bl); + } + bl->props.brightness = MAX_BRIGHTNESS; + + platform_set_drvdata(pdev, bl); + + value = 0; + if (!pdev->dev.platform_data) + max8925_backlight_dt_init(pdev); + + pdata = pdev->dev.platform_data; + if (pdata) { + 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, data->reg_mode_cntl, 0xfe, value); + if (ret < 0) + return ret; + backlight_update_status(bl); + return 0; +} + +static struct platform_driver max8925_backlight_driver = { + .driver = { + .name = "max8925-backlight", + }, + .probe = max8925_backlight_probe, +}; + +module_platform_driver(max8925_backlight_driver); + +MODULE_DESCRIPTION("Backlight Driver for Maxim MAX8925"); +MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:max8925-backlight"); |