drivers/video/backlight/omap1_bl.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Backlight driver for OMAP based boards.
 *
 * Copyright (c) 2006 Andrzej Zaborowski  <balrog@zabor.org>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/backlight.h>
#include <linux/slab.h>
#include <linux/platform_data/omap1_bl.h>

#include <linux/soc/ti/omap1-io.h>
#include <linux/soc/ti/omap1-mux.h>

#define OMAPBL_MAX_INTENSITY		0xff

struct omap_backlight {
	bool enabled;
	int current_intensity;

	struct device *dev;
	struct omap_backlight_config *pdata;
};

static inline void omapbl_send_intensity(int intensity)
{
	omap_writeb(intensity, OMAP_PWL_ENABLE);
}

static inline void omapbl_send_enable(int enable)
{
	omap_writeb(enable, OMAP_PWL_CLK_ENABLE);
}

static void omapbl_enable(struct omap_backlight *bl, bool enable)
{
	if (enable) {
		omapbl_send_intensity(bl->current_intensity);
		omapbl_send_enable(1);
	} else {
		omapbl_send_intensity(0);
		omapbl_send_enable(0);
	}
}

#ifdef CONFIG_PM_SLEEP
static int omapbl_suspend(struct device *dev)
{
	struct backlight_device *bl_dev = dev_get_drvdata(dev);
	struct omap_backlight *bl = bl_get_data(bl_dev);

	omapbl_enable(bl, false);
	return 0;
}

static int omapbl_resume(struct device *dev)
{
	struct backlight_device *bl_dev = dev_get_drvdata(dev);
	struct omap_backlight *bl = bl_get_data(bl_dev);

	omapbl_enable(bl, bl->enabled);
	return 0;
}
#endif

static void omapbl_set_enabled(struct backlight_device *dev, bool enable)
{
	struct omap_backlight *bl = bl_get_data(dev);

	omapbl_enable(bl, enable);
	bl->enabled = enable;
}

static int omapbl_update_status(struct backlight_device *dev)
{
	struct omap_backlight *bl = bl_get_data(dev);
	bool enable;

	if (bl->current_intensity != dev->props.brightness) {
		if (bl->enabled)
			omapbl_send_intensity(dev->props.brightness);
		bl->current_intensity = dev->props.brightness;
	}

	enable = !backlight_is_blank(dev);

	if (enable != bl->enabled)
		omapbl_set_enabled(dev, enable);

	return 0;
}

static int omapbl_get_intensity(struct backlight_device *dev)
{
	struct omap_backlight *bl = bl_get_data(dev);

	return bl->current_intensity;
}

static const struct backlight_ops omapbl_ops = {
	.get_brightness = omapbl_get_intensity,
	.update_status  = omapbl_update_status,
};

static int omapbl_probe(struct platform_device *pdev)
{
	struct backlight_properties props;
	struct backlight_device *dev;
	struct omap_backlight *bl;
	struct omap_backlight_config *pdata = dev_get_platdata(&pdev->dev);

	if (!pdata)
		return -ENXIO;

	bl = devm_kzalloc(&pdev->dev, sizeof(struct omap_backlight),
			  GFP_KERNEL);
	if (unlikely(!bl))
		return -ENOMEM;

	memset(&props, 0, sizeof(struct backlight_properties));
	props.type = BACKLIGHT_RAW;
	props.max_brightness = OMAPBL_MAX_INTENSITY;
	dev = devm_backlight_device_register(&pdev->dev, "omap-bl", &pdev->dev,
					bl, &omapbl_ops, &props);
	if (IS_ERR(dev))
		return PTR_ERR(dev);

	bl->enabled = false;
	bl->current_intensity = 0;

	bl->pdata = pdata;
	bl->dev = &pdev->dev;

	platform_set_drvdata(pdev, dev);

	omap_cfg_reg(PWL);	/* Conflicts with UART3 */

	dev->props.brightness = pdata->default_intensity;
	omapbl_update_status(dev);

	dev_info(&pdev->dev, "OMAP LCD backlight initialised\n");

	return 0;
}

static SIMPLE_DEV_PM_OPS(omapbl_pm_ops, omapbl_suspend, omapbl_resume);

static struct platform_driver omapbl_driver = {
	.probe		= omapbl_probe,
	.driver		= {
		.name	= "omap-bl",
		.pm	= &omapbl_pm_ops,
	},
};

module_platform_driver(omapbl_driver);

MODULE_AUTHOR("Andrzej Zaborowski <balrog@zabor.org>");
MODULE_DESCRIPTION("OMAP LCD Backlight driver");
MODULE_LICENSE("GPL");