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			172 lines
		
	
	
	
		
			5.1 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			172 lines
		
	
	
	
		
			5.1 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
| From bdb802666e76397d228fbfa0f31e6ed4bc800164 Mon Sep 17 00:00:00 2001
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| From: P33M <P33M@github.com>
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| Date: Wed, 21 Oct 2015 14:55:21 +0100
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| Subject: [PATCH] rpi_display: add backlight driver and overlay
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| 
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| Add a mailbox-driven backlight controller for the Raspberry Pi DSI
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| touchscreen display. Requires updated GPU firmware to recognise the
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| mailbox request.
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| 
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| Signed-off-by: Gordon Hollingworth <gordon@raspberrypi.org>
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| 
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| Add Raspberry Pi firmware driver to the dependencies of backlight driver
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| 
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| Otherwise the backlight driver fails to build if the firmware
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| loading driver is not in the kernel
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| 
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| Signed-off-by: Alex Riesen <alexander.riesen@cetitec.com>
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| ---
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|  drivers/video/backlight/Kconfig         |   7 ++
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|  drivers/video/backlight/Makefile        |   1 +
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|  drivers/video/backlight/rpi_backlight.c | 119 ++++++++++++++++++++++++
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|  3 files changed, 127 insertions(+)
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|  create mode 100644 drivers/video/backlight/rpi_backlight.c
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| 
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| --- a/drivers/video/backlight/Kconfig
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| +++ b/drivers/video/backlight/Kconfig
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| @@ -248,6 +248,13 @@ config BACKLIGHT_PWM
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|  	  If you have a LCD backlight adjustable by PWM, say Y to enable
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|  	  this driver.
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|  
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| +config BACKLIGHT_RPI
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| +	tristate "Raspberry Pi display firmware driven backlight"
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| +	depends on RASPBERRYPI_FIRMWARE
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| +	help
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| +	  If you have the Raspberry Pi DSI touchscreen display, say Y to
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| +	  enable the mailbox-controlled backlight driver.
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| +
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|  config BACKLIGHT_DA903X
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|  	tristate "Backlight Driver for DA9030/DA9034 using WLED"
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|  	depends on PMIC_DA903X
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| --- a/drivers/video/backlight/Makefile
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| +++ b/drivers/video/backlight/Makefile
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| @@ -50,6 +50,7 @@ obj-$(CONFIG_BACKLIGHT_PANDORA)		+= pand
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|  obj-$(CONFIG_BACKLIGHT_PCF50633)	+= pcf50633-backlight.o
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|  obj-$(CONFIG_BACKLIGHT_PWM)		+= pwm_bl.o
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|  obj-$(CONFIG_BACKLIGHT_QCOM_WLED)	+= qcom-wled.o
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| +obj-$(CONFIG_BACKLIGHT_RPI)			+= rpi_backlight.o
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|  obj-$(CONFIG_BACKLIGHT_RT4831)		+= rt4831-backlight.o
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|  obj-$(CONFIG_BACKLIGHT_SAHARA)		+= kb3886_bl.o
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|  obj-$(CONFIG_BACKLIGHT_SKY81452)	+= sky81452-backlight.o
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| --- /dev/null
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| +++ b/drivers/video/backlight/rpi_backlight.c
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| @@ -0,0 +1,119 @@
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| +/*
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| + * rpi_bl.c - Backlight controller through VPU
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| + *
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| + * This program is free software; you can redistribute it and/or modify
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| + * it under the terms of the GNU General Public License version 2 as
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| + * published by the Free Software Foundation.
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| + */
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| +
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| +#include <linux/backlight.h>
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| +#include <linux/err.h>
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| +#include <linux/fb.h>
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| +#include <linux/gpio.h>
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| +#include <linux/init.h>
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| +#include <linux/kernel.h>
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| +#include <linux/module.h>
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| +#include <linux/of.h>
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| +#include <linux/of_gpio.h>
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| +#include <linux/platform_device.h>
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| +#include <linux/slab.h>
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| +#include <soc/bcm2835/raspberrypi-firmware.h>
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| +
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| +struct rpi_backlight {
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| +	struct device *dev;
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| +	struct device *fbdev;
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| +	struct rpi_firmware *fw;
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| +};
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| +
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| +static int rpi_backlight_update_status(struct backlight_device *bl)
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| +{
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| +	struct rpi_backlight *gbl = bl_get_data(bl);
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| +	int brightness = bl->props.brightness;
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| +	int ret;
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| +
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| +	if (bl->props.power != FB_BLANK_UNBLANK ||
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| +	    bl->props.fb_blank != FB_BLANK_UNBLANK ||
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| +	    bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
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| +		brightness = 0;
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| +
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| +	ret = rpi_firmware_property(gbl->fw,
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| +			RPI_FIRMWARE_FRAMEBUFFER_SET_BACKLIGHT,
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| +			&brightness, sizeof(brightness));
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| +	if (ret) {
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| +		dev_err(gbl->dev, "Failed to set brightness\n");
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| +		return ret;
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| +	}
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| +
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| +	if (brightness < 0) {
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| +		dev_err(gbl->dev, "Backlight change failed\n");
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| +		return -EAGAIN;
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| +	}
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| +
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| +	return 0;
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| +}
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| +
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| +static const struct backlight_ops rpi_backlight_ops = {
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| +	.options	= BL_CORE_SUSPENDRESUME,
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| +	.update_status	= rpi_backlight_update_status,
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| +};
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| +
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| +static int rpi_backlight_probe(struct platform_device *pdev)
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| +{
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| +	struct backlight_properties props;
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| +	struct backlight_device *bl;
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| +	struct rpi_backlight *gbl;
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| +	struct device_node *fw_node;
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| +
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| +	gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
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| +	if (gbl == NULL)
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| +		return -ENOMEM;
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| +
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| +	gbl->dev = &pdev->dev;
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| +
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| +	fw_node = of_parse_phandle(pdev->dev.of_node, "firmware", 0);
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| +	if (!fw_node) {
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| +		dev_err(&pdev->dev, "Missing firmware node\n");
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| +		return -ENOENT;
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| +	}
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| +
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| +	gbl->fw = rpi_firmware_get(fw_node);
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| +	if (!gbl->fw)
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| +		return -EPROBE_DEFER;
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| +
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| +	memset(&props, 0, sizeof(props));
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| +	props.type = BACKLIGHT_RAW;
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| +	props.max_brightness = 255;
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| +	bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
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| +					&pdev->dev, gbl, &rpi_backlight_ops,
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| +					&props);
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| +	if (IS_ERR(bl)) {
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| +		dev_err(&pdev->dev, "failed to register backlight\n");
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| +		return PTR_ERR(bl);
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| +	}
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| +
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| +	bl->props.brightness = 255;
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| +	backlight_update_status(bl);
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| +
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| +	platform_set_drvdata(pdev, bl);
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| +	return 0;
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| +}
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| +
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| +static const struct of_device_id rpi_backlight_of_match[] = {
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| +	{ .compatible = "raspberrypi,rpi-backlight" },
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| +	{ /* sentinel */ }
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| +};
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| +MODULE_DEVICE_TABLE(of, rpi_backlight_of_match);
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| +
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| +static struct platform_driver rpi_backlight_driver = {
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| +	.driver		= {
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| +		.name		= "rpi-backlight",
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| +		.of_match_table = of_match_ptr(rpi_backlight_of_match),
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| +	},
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| +	.probe		= rpi_backlight_probe,
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| +};
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| +
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| +module_platform_driver(rpi_backlight_driver);
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| +
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| +MODULE_AUTHOR("Gordon Hollingworth <gordon@raspberrypi.org>");
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| +MODULE_DESCRIPTION("Raspberry Pi mailbox based Backlight Driver");
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| +MODULE_LICENSE("GPL");
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