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173 lines
5.1 KiB
Diff
173 lines
5.1 KiB
Diff
From 5dcbf6d1aa6e33987082e9c8ac64e74f7b6bad58 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 089/806] rpi_display: add backlight driver and overlay
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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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Signed-off-by: Gordon Hollingworth <gordon@raspberrypi.org>
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Add Raspberry Pi firmware driver to the dependencies of backlight driver
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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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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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--- a/drivers/video/backlight/Kconfig
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+++ b/drivers/video/backlight/Kconfig
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@@ -272,6 +272,13 @@ 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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+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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@@ -52,6 +52,7 @@ obj-$(CONFIG_BACKLIGHT_PANDORA) += pand
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obj-$(CONFIG_BACKLIGHT_PCF50633) += pcf50633-backlight.o
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obj-$(CONFIG_BACKLIGHT_PM8941_WLED) += pm8941-wled.o
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obj-$(CONFIG_BACKLIGHT_PWM) += pwm_bl.o
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+obj-$(CONFIG_BACKLIGHT_RPI) += rpi_backlight.o
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obj-$(CONFIG_BACKLIGHT_SAHARA) += kb3886_bl.o
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obj-$(CONFIG_BACKLIGHT_SKY81452) += sky81452-backlight.o
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obj-$(CONFIG_BACKLIGHT_TOSA) += tosa_bl.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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