[PATCH 07/11] ARM: dts: Enable N900 keybaord sleep leds by default

Tony Lindgren tony at atomide.com
Wed Apr 23 14:07:50 PDT 2014

* Aaro Koskinen <aaro.koskinen at iki.fi> [140411 16:39]:
> Hi,
> On Thu, Apr 10, 2014 at 04:47:15PM -0700, Tony Lindgren wrote:
> > +        leds {
> > +                compatible = "gpio-leds";
> > +                heartbeat {
> > +                        label = "debug::sleep";
> > +                        gpios = <&gpio6 2 GPIO_ACTIVE_HIGH>;  /* gpio162 */
> > +                        linux,default-trigger = "default-on";
> Just some very minor nits, spaces should be converted to TABs here
> for indent, and patch title should say "keyboard" instead of "keybaord".
> Acked-by: Aaro Koskinen <aaro.koskinen at iki.fi>

Thanks and sorry for the delay, got sidetracked with some GPMC bugs.
Here's the updated version of this patch.


8< ------------------------
From: Tony Lindgren <tony at atomide.com>
Date: Wed, 23 Apr 2014 13:59:24 -0700
Subject: [PATCH] ARM: dts: Enable N900 keyboard sleep leds by default

On N900 there are nice LEDs that show the state of the
sys_clkreq and sys_off_mode pins.

These LEDs go low when the system enters deeper idle
states. The left LED shows the state of the sys_clkreq
pin, and goes off during retention idle. The right LED
shows the state of sys_off_mode pin and both go off
during off idle.

As N900 is a battery operated device, these LEDs should
be off most of the time. So let's enable them by default
so we can make sure the system is mostly idle.

This allows the maintainers to also immediately test
patches for PM regressions by looking at the LEDs,
which certainly makes my life easier.

The LED can naturally be disabled during runtime with:

# echo none > /sys/class/leds/debug::sleep/trigger

Note that we don't currently have support for omap3
errata 1.158 that remuxes GPIO pins to INPUT_PULLUP |
MUX_MODE7 for the duration of idle. This means that the
GPIO pins set high will go down during off idle. In this
case it does not matter as the sys_off_mode goes down
too, but there's still a slim chance of false off idle
LED signals. If in doubt, false LED signals can be
verified by the sys_off_mode or vdd_core values.

Also note that to allow the UARTs to autoidle, the
following needs to be run on N900 to enable off idle:

uarts=$(find /sys/class/tty/ttyO*/device/power/ -type d)
for uart in $uarts; do
	echo 3000 > $uart/autosuspend_delay_ms

uarts=$(find /sys/class/tty/ttyO*/power/ -type d)
for uart in $uarts; do
	echo enabled > $uart/wakeup
	echo auto > $uart/control

echo 1 > /sys/kernel/debug/pm_debug/enable_off_mode

For retention idle, change the above to set 0 to

Also note that without the twl4030 PM scripts the actual
voltage scaling won't happen for off idle so we only get
voltage scaling over I2C4 for retention idle. I'll do
some device tree patches for those also a bit later on.

Cc: Kevin Hilman <khilman at linaro.org>
Cc: Nishanth Menon <nm at ti.com>
Cc: Pali Rohár <pali.rohar at gmail.com>
Cc: Paul Walmsley <paul at pwsan.com>
Cc: Pavel Machek <pavel at ucw.cz>
Cc: Sebastian Reichel <sre at kernel.org>
Cc: Tero Kristo <t-kristo at ti.com>
Acked-by: Aaro Koskinen <aaro.koskinen at iki.fi>
Signed-off-by: Tony Lindgren <tony at atomide.com>

--- a/arch/arm/boot/dts/omap3-n900.dts
+++ b/arch/arm/boot/dts/omap3-n900.dts
@@ -21,6 +21,17 @@
+	leds {
+		compatible = "gpio-leds";
+		heartbeat {
+			label = "debug::sleep";
+			gpios = <&gpio6 2 GPIO_ACTIVE_HIGH>;  /* gpio162 */
+			linux,default-trigger = "default-on";
+			pinctrl-names = "default";
+			pinctrl-0 = <&debug_leds>;
+		};
+	};
 	memory {
 		device_type = "memory";
 		reg = <0x80000000 0x10000000>; /* 256 MB */
@@ -114,6 +125,12 @@
+	debug_leds: pinmux_debug_led_pins {
+		pinctrl-single,pins = <
+			OMAP3_CORE1_IOPAD(0x2198, PIN_OUTPUT | MUX_MODE4)	/* mcbsp1_clkx.gpio_162 */
+		>;
+	};
 	mmc1_pins: pinmux_mmc1_pins {
 		pinctrl-single,pins = <
 			0x114 (PIN_INPUT_PULLUP | MUX_MODE0)	/* sdmmc1_clk */

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