From mboxrd@z Thu Jan  1 00:00:00 1970
From: Michal Simek <monstr-pSz03upnqPeHXe+LvDLADg@public.gmane.org>
Subject: Gpio reset handling
Date: Tue, 15 Sep 2009 20:32:49 +0200
Message-ID: <4AAFDDD1.9070702@monstr.eu>
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Hi All,

I would like to find out proper way how to handle xilinx reset gpio.
We are using gpio for soft reset.

I read led.txt in Documentation and currently are used/supported some triggers
but reset is not there.

Led gpio is clear because example is in kernel (xpedite5301.dts for example)

Here is description for mixed reset/heartbeat/led gpio
1. line - soft reset
2. line - phy reset for example or any different one
3. line - heartbeat
4. line - led


Not sure if is first line from 1 or 0 - but doesn't matter right now.



		gpio_res: gpio@81400000 {
			compatible = "xlnx,xps-gpio-1.00.a";
			interrupt-parent = <&xps_intc_0>;
			interrupts = < 7 2 >;
			reg = < 0x81400000 0x10000 >;
...
			xlnx,gpio-width = <0x8>;
...
		} ;

gpio-leds {
	compatible = "gpio-leds";
	heartbeat {
		label = "Heartbeat";
		gpios = <&gpio_res 4 1>;
		linux,default-trigger = "heartbeat";
	}

	green {
		label = "Green"
		gpios = <&gpio_res 5 1>;
	}
}

Ok and here about description of reset port
I see two option to write new trigger
1. new reset trigger and add it to gpio-leds node - but this should be in gpio-leds node which make
no sense to me

	reset {
		label = "Heartbeat";
		gpios = <&gpio_res 3 1>;
		linux,default-trigger = "reset";
	}

2. create own reset node

reset {
	compatible = "gpio-reset";
	reset0 {
		label "Soft reset";
		gpios = <&gpio_res 1 1>;
	}

	reset1 {
		label "Phy reset";
		gpios = <&gpio_res 2 1>;
	}
}

For this node there should be better reset description not just label with different description.
I expect that it will be useful soft and hard reset and maybe you can find some others.


Thanks for you help,
Michal



-- 
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian