openwrt/target/linux/bcm27xx/patches-4.19/950-0087-rpi_display-add-backlight-driver-and-overlay.patch
Adrian Schmutzler 7d7aa2fd92 brcm2708: rename target to bcm27xx
This change makes the names of Broadcom targets consistent by using
the common notation based on SoC/CPU ID (which is used internally
anyway), bcmXXXX instead of brcmXXXX.
This is even used for target TITLE in make menuconfig already,
only the short target name used brcm so far.

Despite, since subtargets range from bcm2708 to bcm2711, it seems
appropriate to use bcm27xx instead of bcm2708 (again, as already done
for BOARDNAME).

This also renames the packages brcm2708-userland and brcm2708-gpu-fw.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Acked-by: Álvaro Fernández Rojas <noltari@gmail.com>
2020-02-14 14:10:51 +01:00

173 lines
5.0 KiB
Diff

From 5dcbf6d1aa6e33987082e9c8ac64e74f7b6bad58 Mon Sep 17 00:00:00 2001
From: P33M <P33M@github.com>
Date: Wed, 21 Oct 2015 14:55:21 +0100
Subject: [PATCH] rpi_display: add backlight driver and overlay
Add a mailbox-driven backlight controller for the Raspberry Pi DSI
touchscreen display. Requires updated GPU firmware to recognise the
mailbox request.
Signed-off-by: Gordon Hollingworth <gordon@raspberrypi.org>
Add Raspberry Pi firmware driver to the dependencies of backlight driver
Otherwise the backlight driver fails to build if the firmware
loading driver is not in the kernel
Signed-off-by: Alex Riesen <alexander.riesen@cetitec.com>
---
drivers/video/backlight/Kconfig | 7 ++
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/rpi_backlight.c | 119 ++++++++++++++++++++++++
3 files changed, 127 insertions(+)
create mode 100644 drivers/video/backlight/rpi_backlight.c
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -272,6 +272,13 @@ config BACKLIGHT_PWM
If you have a LCD backlight adjustable by PWM, say Y to enable
this driver.
+config BACKLIGHT_RPI
+ tristate "Raspberry Pi display firmware driven backlight"
+ depends on RASPBERRYPI_FIRMWARE
+ help
+ If you have the Raspberry Pi DSI touchscreen display, say Y to
+ enable the mailbox-controlled backlight driver.
+
config BACKLIGHT_DA903X
tristate "Backlight Driver for DA9030/DA9034 using WLED"
depends on PMIC_DA903X
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -52,6 +52,7 @@ obj-$(CONFIG_BACKLIGHT_PANDORA) += pand
obj-$(CONFIG_BACKLIGHT_PCF50633) += pcf50633-backlight.o
obj-$(CONFIG_BACKLIGHT_PM8941_WLED) += pm8941-wled.o
obj-$(CONFIG_BACKLIGHT_PWM) += pwm_bl.o
+obj-$(CONFIG_BACKLIGHT_RPI) += rpi_backlight.o
obj-$(CONFIG_BACKLIGHT_SAHARA) += kb3886_bl.o
obj-$(CONFIG_BACKLIGHT_SKY81452) += sky81452-backlight.o
obj-$(CONFIG_BACKLIGHT_TOSA) += tosa_bl.o
--- /dev/null
+++ b/drivers/video/backlight/rpi_backlight.c
@@ -0,0 +1,119 @@
+/*
+ * rpi_bl.c - Backlight controller through VPU
+ *
+ * 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/backlight.h>
+#include <linux/err.h>
+#include <linux/fb.h>
+#include <linux/gpio.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+struct rpi_backlight {
+ struct device *dev;
+ struct device *fbdev;
+ struct rpi_firmware *fw;
+};
+
+static int rpi_backlight_update_status(struct backlight_device *bl)
+{
+ struct rpi_backlight *gbl = bl_get_data(bl);
+ int brightness = bl->props.brightness;
+ int ret;
+
+ if (bl->props.power != FB_BLANK_UNBLANK ||
+ bl->props.fb_blank != FB_BLANK_UNBLANK ||
+ bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
+ brightness = 0;
+
+ ret = rpi_firmware_property(gbl->fw,
+ RPI_FIRMWARE_FRAMEBUFFER_SET_BACKLIGHT,
+ &brightness, sizeof(brightness));
+ if (ret) {
+ dev_err(gbl->dev, "Failed to set brightness\n");
+ return ret;
+ }
+
+ if (brightness < 0) {
+ dev_err(gbl->dev, "Backlight change failed\n");
+ return -EAGAIN;
+ }
+
+ return 0;
+}
+
+static const struct backlight_ops rpi_backlight_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .update_status = rpi_backlight_update_status,
+};
+
+static int rpi_backlight_probe(struct platform_device *pdev)
+{
+ struct backlight_properties props;
+ struct backlight_device *bl;
+ struct rpi_backlight *gbl;
+ struct device_node *fw_node;
+
+ gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
+ if (gbl == NULL)
+ return -ENOMEM;
+
+ gbl->dev = &pdev->dev;
+
+ fw_node = of_parse_phandle(pdev->dev.of_node, "firmware", 0);
+ if (!fw_node) {
+ dev_err(&pdev->dev, "Missing firmware node\n");
+ return -ENOENT;
+ }
+
+ gbl->fw = rpi_firmware_get(fw_node);
+ if (!gbl->fw)
+ return -EPROBE_DEFER;
+
+ memset(&props, 0, sizeof(props));
+ props.type = BACKLIGHT_RAW;
+ props.max_brightness = 255;
+ bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
+ &pdev->dev, gbl, &rpi_backlight_ops,
+ &props);
+ if (IS_ERR(bl)) {
+ dev_err(&pdev->dev, "failed to register backlight\n");
+ return PTR_ERR(bl);
+ }
+
+ bl->props.brightness = 255;
+ backlight_update_status(bl);
+
+ platform_set_drvdata(pdev, bl);
+ return 0;
+}
+
+static const struct of_device_id rpi_backlight_of_match[] = {
+ { .compatible = "raspberrypi,rpi-backlight" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rpi_backlight_of_match);
+
+static struct platform_driver rpi_backlight_driver = {
+ .driver = {
+ .name = "rpi-backlight",
+ .of_match_table = of_match_ptr(rpi_backlight_of_match),
+ },
+ .probe = rpi_backlight_probe,
+};
+
+module_platform_driver(rpi_backlight_driver);
+
+MODULE_AUTHOR("Gordon Hollingworth <gordon@raspberrypi.org>");
+MODULE_DESCRIPTION("Raspberry Pi mailbox based Backlight Driver");
+MODULE_LICENSE("GPL");