From e06bf63e08152f23fb70db7d9ac1abb9a9b39399 Mon Sep 17 00:00:00 2001
From: Ciro Santilli <ciro.santilli@gmail.com>
Date: Mon, 3 Jul 2017 08:58:14 +0100
Subject: [PATCH] DTC tools, correct SYSCON LEDs

---
 buildroot_config_fragment |  5 +++++
 kernel_config_fragment    | 31 +++++++++++++++++++------------
 rootfs_overlay/gpio.sh    |  1 +
 run                       |  2 +-
 4 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/buildroot_config_fragment b/buildroot_config_fragment
index 081a27d..9be8177 100644
--- a/buildroot_config_fragment
+++ b/buildroot_config_fragment
@@ -39,3 +39,8 @@ BR2_PACKAGE_TRACE_CMD=y
 # GPIO: lsgpio, gpio-event-mon, gpio-hammer
 BR2_PACKAGE_LINUX_TOOLS=y
 BR2_PACKAGE_LINUX_TOOLS_GPIO=y
+
+# DTC
+BR2_PACKAGE_DTC=y
+BR2_PACKAGE_DTC_PROGRAMS=y
+BR2_PACKAGE_HOST_DTC=y
diff --git a/kernel_config_fragment b/kernel_config_fragment
index d033a6c..53c5433 100644
--- a/kernel_config_fragment
+++ b/kernel_config_fragment
@@ -58,17 +58,11 @@ CONFIG_TRACER_SNAPSHOT=y
 # cat /sys/kernel/debug/kernel_page_tables
 CONFIG_X86_PTDUMP=y
 
-# LEDs.
+# LEDs. ARM only.
 #
-#     modprobe led-class
-#     modprobe leds-versatile
-#     ls /sys/class/leds
-#
-# TODO: the LEDs don't appear there. There are some entires under:
-#
-#     /sys/devices/platform/10000000.core-module/10000000.core-module:led@08.0/
-#
-# but they don't have brightness file.
+#     cd /sys/class/leds/versatile:0
+#     cat max_brightness
+#     echo 255 >brightness
 #
 # https://raspberrypi.stackexchange.com/questions/697/how-do-i-control-the-system-leds-using-my-software
 #
@@ -81,10 +75,24 @@ CONFIG_X86_PTDUMP=y
 #
 # - arch/arm/boot/dts/versatile-pb.dts
 # - drivers/leds/led-class.c
-# - drivers/leds/leds-versatile.c
+# - drivers/leds/leds-sysctl.c
 #
+# Try hacking QEMU's `hw/misc/arm_sysctl.c` with a printf:
+#
+#     static void arm_sysctl_write(void *opaque, hwaddr offset,
+#                                 uint64_t val, unsigned size)
+#     {
+#         arm_sysctl_state *s = (arm_sysctl_state *)opaque;
+#
+#         switch (offset) {
+#         case 0x08: /* LED */
+#             printf("LED val = %llx\n", (unsigned long long)val);
+#
+# to obeserve when the callback is made. But beware that one of the LEDs
+# has a heartbeat trigger by default (specified on dts), so it will produce a lot of output.
 CONFIG_LEDS_CLASS=y
 CONFIG_LEDS_CLASS_FLASH=y
+CONFIG_LEDS_SYSCON=y
 CONFIG_LEDS_TRIGGERS=y
 CONFIG_LEDS_TRIGGER_BACKLIGHT=y
 CONFIG_LEDS_TRIGGER_CPU=y
@@ -93,7 +101,6 @@ CONFIG_LEDS_TRIGGER_GPIO=y
 CONFIG_LEDS_TRIGGER_HEARTBEAT=y
 CONFIG_LEDS_TRIGGER_ONESHOT=y
 CONFIG_LEDS_TRIGGER_TIMER=y
-CONFIG_LEDS_VERSATILE=y
 CONFIG_NEW_LEDS=y
 
 # GPIO.
diff --git a/rootfs_overlay/gpio.sh b/rootfs_overlay/gpio.sh
index 512a903..a71a6e8 100755
--- a/rootfs_overlay/gpio.sh
+++ b/rootfs_overlay/gpio.sh
@@ -1,4 +1,5 @@
 #!/bin/sh
+# ARM only.
 # https://raspberrypi.stackexchange.com/questions/56373/is-it-possible-to-get-the-state-of-the-leds-and-gpios-in-a-qemu-emulation-like-t/69267#69267
 set -e
 cd /sys/class/gpio
diff --git a/run b/run
index a555297..feaaa73 100755
--- a/run
+++ b/run
@@ -41,8 +41,8 @@ env \
   O="$outdir" \
   BR2_JLEVEL="$(($(nproc) - 2))" \
   HOST_QEMU_OPTS="--enable-debug --enable-sdl --extra-cflags='-DDEBUG_PL061=1' --with-sdlabi=2.0" \
-  host-qemu-reconfigure \
   host-qemu-rebuild \
+  linux-rebuild \
   kernel_module-rebuild \
   all \
 ;