Re: [PATCH v6 1/8] binding-doc: power: pwrseq-generic: add binding doc for generic power sequence library

From: Peter Chen <hzpeterchen@gmail.com>
To: Vaibhav Hiremath <vaibhav.hiremath@linaro.org>
Cc: Peter Chen <peter.chen@nxp.com>,
	gregkh@linuxfoundation.org, stern@rowland.harvard.edu,
	ulf.hansson@linaro.org, broonie@kernel.org, sre@kernel.org,
	robh+dt@kernel.org, shawnguo@kernel.org, dbaryshkov@gmail.com,
	dwmw3@infradead.org, k.kozlowski@samsung.com,
	linux-arm-kernel@lists.infradead.org, p.zabel@pengutronix.de,
	devicetree@vger.kernel.org, pawel.moll@arm.com,
	mark.rutland@arm.com, linux-usb@vger.kernel.org, arnd@arndb.de,
	s.hauer@pengutronix.de, mail@maciej.szmigiero.name,
	troy.kisky@boundarydevices.com, festevam@gmail.com,
	oscar@naiandei.net, stephen.boyd@linaro.org,
	linux-pm@vger.kernel.org, stillcompiling@gmail.com,
	linux-kernel@vger.kernel.org, mka@chromium.org
Subject: Re: [PATCH v6 1/8] binding-doc: power: pwrseq-generic: add binding doc for generic power sequence library
Date: Fri, 2 Sep 2016 09:00:30 +0800	[thread overview]
Message-ID: <20160902010030.GA11262@shlinux2> (raw)
In-Reply-To: <6832cc55-831a-1188-4878-bbbf0b3c3be8@linaro.org>

On Thu, Sep 01, 2016 at 01:33:22PM +0530, Vaibhav Hiremath wrote:
> 
> 
> On Monday 15 August 2016 02:43 PM, Peter Chen wrote:
> >Add binding doc for generic power sequence library.
> >
> >Signed-off-by: Peter Chen <peter.chen@nxp.com>
> >Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
> >Acked-by: Rob Herring <robh@kernel.org>
> >---
> >  .../bindings/power/pwrseq/pwrseq-generic.txt       | 48 ++++++++++++++++++++++
> >  1 file changed, 48 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
> >
> >diff --git a/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
> >new file mode 100644
> >index 0000000..ebf0d47
> >--- /dev/null
> >+++ b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
> >@@ -0,0 +1,48 @@
> >+The generic power sequence library
> >+
> >+Some hard-wired devices (eg USB/MMC) need to do power sequence before
> >+the device can be enumerated on the bus, the typical power sequence
> >+like: enable USB PHY clock, toggle reset pin, etc. But current
> >+Linux device driver lacks of such code to do it, it may cause some
> >+hard-wired devices works abnormal or can't be recognized by
> >+controller at all. The power sequence will be done before this device
> >+can be found at the bus.
> >+
> >+The power sequence properties is under the device node.
> >+
> >+Optional properties:
> >+- clocks: the input clocks for device.
> >+- reset-gpios: Should specify the GPIO for reset.
> >+- reset-duration-us: the duration in microsecond for assert reset signal.
> >+
> >+Below is the example of USB power sequence properties on USB device
> >+nodes which have two level USB hubs.
> >+
> >+&usbotg1 {
> >+	vbus-supply = <&reg_usb_otg1_vbus>;
> >+	pinctrl-names = "default";
> >+	pinctrl-0 = <&pinctrl_usb_otg1_id>;
> >+	status = "okay";
> >+
> >+	#address-cells = <1>;
> >+	#size-cells = <0>;
> >+	genesys: hub@1 {
> >+		compatible = "usb5e3,608";
> >+		reg = <1>;
> >+
> >+		clocks = <&clks IMX6SX_CLK_CKO>;
> >+		reset-gpios = <&gpio4 5 GPIO_ACTIVE_LOW>; /* hub reset pin */
> >+		reset-duration-us = <10>;
> >+
> >+		#address-cells = <1>;
> >+		#size-cells = <0>;
> >+		asix: ethernet@1 {
> >+			compatible = "usbb95,1708";
> 
> So I assume, with our recent discussion and the change
> we are proposing, the library would have some knowledge
> about this compatible string, right?

Yes

> 
> what I was asking on other email was, how are you connecting
> multiple power sequence libraries to their respective consumers ?
> 

The consumers has its of_node, then it can find related power sequence
library according to compatible string.

-- 

Best Regards,
Peter Chen