target/linux/brcm2708/patches-4.9/950-0085-rpi_display-add-backlight-driver-and-overlay.patch

   1 From ae5ae9278768c3d096910705bfa9af85da20a8cf Mon Sep 17 00:00:00 2001
   2 From: P33M <P33M@github.com>
   3 Date: Wed, 21 Oct 2015 14:55:21 +0100
   4 Subject: [PATCH] rpi_display: add backlight driver and overlay
   5
   6 Add a mailbox-driven backlight controller for the Raspberry Pi DSI
   7 touchscreen display. Requires updated GPU firmware to recognise the
   8 mailbox request.
   9
  10 Signed-off-by: Gordon Hollingworth <gordon@raspberrypi.org>
  11 ---
  12  drivers/video/backlight/Kconfig         |   6 ++
  13  drivers/video/backlight/Makefile        |   1 +
  14  drivers/video/backlight/rpi_backlight.c | 119 ++++++++++++++++++++++++++++++++
  15  3 files changed, 126 insertions(+)
  16  create mode 100644 drivers/video/backlight/rpi_backlight.c
  17
  18 --- a/drivers/video/backlight/Kconfig
  19 +++ b/drivers/video/backlight/Kconfig
  20 @@ -265,6 +265,12 @@ config BACKLIGHT_PWM
  21           If you have a LCD backlight adjustable by PWM, say Y to enable
  22           this driver.
  23
  24 +config BACKLIGHT_RPI
  25 +       tristate "Raspberry Pi display firmware driven backlight"
  26 +       help
  27 +         If you have the Raspberry Pi DSI touchscreen display, say Y to
  28 +         enable the mailbox-controlled backlight driver.
  29 +
  30  config BACKLIGHT_DA903X
  31         tristate "Backlight Driver for DA9030/DA9034 using WLED"
  32         depends on PMIC_DA903X
  33 --- a/drivers/video/backlight/Makefile
  34 +++ b/drivers/video/backlight/Makefile
  35 @@ -50,6 +50,7 @@ obj-$(CONFIG_BACKLIGHT_PANDORA)               += pand
  36  obj-$(CONFIG_BACKLIGHT_PCF50633)       += pcf50633-backlight.o
  37  obj-$(CONFIG_BACKLIGHT_PM8941_WLED)    += pm8941-wled.o
  38  obj-$(CONFIG_BACKLIGHT_PWM)            += pwm_bl.o
  39 +obj-$(CONFIG_BACKLIGHT_RPI)                    += rpi_backlight.o
  40  obj-$(CONFIG_BACKLIGHT_SAHARA)         += kb3886_bl.o
  41  obj-$(CONFIG_BACKLIGHT_SKY81452)       += sky81452-backlight.o
  42  obj-$(CONFIG_BACKLIGHT_TOSA)           += tosa_bl.o
  43 --- /dev/null
  44 +++ b/drivers/video/backlight/rpi_backlight.c
  45 @@ -0,0 +1,119 @@
  46 +/*
  47 + * rpi_bl.c - Backlight controller through VPU
  48 + *
  49 + * This program is free software; you can redistribute it and/or modify
  50 + * it under the terms of the GNU General Public License version 2 as
  51 + * published by the Free Software Foundation.
  52 + */
  53 +
  54 +#include <linux/backlight.h>
  55 +#include <linux/err.h>
  56 +#include <linux/fb.h>
  57 +#include <linux/gpio.h>
  58 +#include <linux/init.h>
  59 +#include <linux/kernel.h>
  60 +#include <linux/module.h>
  61 +#include <linux/of.h>
  62 +#include <linux/of_gpio.h>
  63 +#include <linux/platform_device.h>
  64 +#include <linux/slab.h>
  65 +#include <soc/bcm2835/raspberrypi-firmware.h>
  66 +
  67 +struct rpi_backlight {
  68 +       struct device *dev;
  69 +       struct device *fbdev;
  70 +       struct rpi_firmware *fw;
  71 +};
  72 +
  73 +static int rpi_backlight_update_status(struct backlight_device *bl)
  74 +{
  75 +       struct rpi_backlight *gbl = bl_get_data(bl);
  76 +       int brightness = bl->props.brightness;
  77 +       int ret;
  78 +
  79 +       if (bl->props.power != FB_BLANK_UNBLANK ||
  80 +           bl->props.fb_blank != FB_BLANK_UNBLANK ||
  81 +           bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
  82 +               brightness = 0;
  83 +
  84 +       ret = rpi_firmware_property(gbl->fw,
  85 +                       RPI_FIRMWARE_FRAMEBUFFER_SET_BACKLIGHT,
  86 +                       &brightness, sizeof(brightness));
  87 +       if (ret) {
  88 +               dev_err(gbl->dev, "Failed to set brightness\n");
  89 +               return ret;
  90 +       }
  91 +
  92 +       if (brightness < 0) {
  93 +               dev_err(gbl->dev, "Backlight change failed\n");
  94 +               return -EAGAIN;
  95 +       }
  96 +
  97 +       return 0;
  98 +}
  99 +
 100 +static const struct backlight_ops rpi_backlight_ops = {
 101 +       .options        = BL_CORE_SUSPENDRESUME,
 102 +       .update_status  = rpi_backlight_update_status,
 103 +};
 104 +
 105 +static int rpi_backlight_probe(struct platform_device *pdev)
 106 +{
 107 +       struct backlight_properties props;
 108 +       struct backlight_device *bl;
 109 +       struct rpi_backlight *gbl;
 110 +       struct device_node *fw_node;
 111 +
 112 +       gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
 113 +       if (gbl == NULL)
 114 +               return -ENOMEM;
 115 +
 116 +       gbl->dev = &pdev->dev;
 117 +
 118 +       fw_node = of_parse_phandle(pdev->dev.of_node, "firmware", 0);
 119 +       if (!fw_node) {
 120 +               dev_err(&pdev->dev, "Missing firmware node\n");
 121 +               return -ENOENT;
 122 +       }
 123 +
 124 +       gbl->fw = rpi_firmware_get(fw_node);
 125 +       if (!gbl->fw)
 126 +               return -EPROBE_DEFER;
 127 +
 128 +       memset(&props, 0, sizeof(props));
 129 +       props.type = BACKLIGHT_RAW;
 130 +       props.max_brightness = 255;
 131 +       bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
 132 +                                       &pdev->dev, gbl, &rpi_backlight_ops,
 133 +                                       &props);
 134 +       if (IS_ERR(bl)) {
 135 +               dev_err(&pdev->dev, "failed to register backlight\n");
 136 +               return PTR_ERR(bl);
 137 +       }
 138 +
 139 +       bl->props.brightness = 255;
 140 +       backlight_update_status(bl);
 141 +
 142 +       platform_set_drvdata(pdev, bl);
 143 +       return 0;
 144 +}
 145 +
 146 +static const struct of_device_id rpi_backlight_of_match[] = {
 147 +       { .compatible = "raspberrypi,rpi-backlight" },
 148 +       { /* sentinel */ }
 149 +};
 150 +MODULE_DEVICE_TABLE(of, rpi_backlight_of_match);
 151 +
 152 +static struct platform_driver rpi_backlight_driver = {
 153 +       .driver         = {
 154 +               .name           = "rpi-backlight",
 155 +               .of_match_table = of_match_ptr(rpi_backlight_of_match),
 156 +       },
 157 +       .probe          = rpi_backlight_probe,
 158 +};
 159 +
 160 +module_platform_driver(rpi_backlight_driver);
 161 +
 162 +MODULE_AUTHOR("Gordon Hollingworth <gordon@raspberrypi.org>");
 163 +MODULE_DESCRIPTION("Raspberry Pi mailbox based Backlight Driver");
 164 +MODULE_LICENSE("GPL");