From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Tissoires Subject: Re: [PATCH v2 2/2] devicetree: i2c-hid: Add reset property Date: Mon, 6 Nov 2017 10:06:30 +0100 Message-ID: <20171106090630.GF9728@mail.corp.redhat.com> References: <1509418996-25348-1-git-send-email-hl@rock-chips.com> <1509418996-25348-2-git-send-email-hl@rock-chips.com> <20171101220208.gixv6anohp5q4kh2@rob-hp-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <20171101220208.gixv6anohp5q4kh2@rob-hp-laptop> Sender: linux-kernel-owner@vger.kernel.org To: Rob Herring Cc: Lin Huang , dmitry.torokhov@gmail.com, jikos@kernel.org, jani.nikula@intel.com, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, briannorris@chromium.org, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org Hi Rob, On Nov 01 2017 or thereabouts, Rob Herring wrote: > On Tue, Oct 31, 2017 at 11:03:16AM +0800, Lin Huang wrote: > > Document a "reset" and "assert-reset-us", it can be used for > > driver control reset property. And reuse post-power-on-delay-ms > > for deassert reset delay. > > "dt-bindings: input: " for the subject please. > > > > > Signed-off-by: Lin Huang > > --- > > Documentation/devicetree/bindings/input/hid-over-i2c.txt | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/devicetree/bindings/input/hid-over-i2c.txt b/Documentation/devicetree/bindings/input/hid-over-i2c.txt > > index 28e8bd8..6ab0eed 100644 > > --- a/Documentation/devicetree/bindings/input/hid-over-i2c.txt > > +++ b/Documentation/devicetree/bindings/input/hid-over-i2c.txt > > @@ -31,7 +31,9 @@ device-specific compatible properties, which should be used in addition to the > > > > - vdd-supply: phandle of the regulator that provides the supply voltage. > > - post-power-on-delay-ms: time required by the device after enabling its regulators > > - before it is ready for communication. Must be used with 'vdd-supply'. > > + or deassert reset pin before it is ready for communication. > > +- reset: phandle of the gpio that provides for hid reset pin. > > The kernel api takes "reset", but the property is "reset-gpios". In the same way the generic regulator interface handles vdd-supply, is there any generic OF handling of reset lines? As far as I can tell, there are 97 references of reset-gpios in my tree, and I wonder if all the matching drivers need to rewrite the same code to set the reset line on power on/off. I am worried because here, 1/2 writes "arbitrary" 0 and 1 to the gpios, and nothing prevent a manufacturer to invert the required voltages on the reset lines, meaning there will be a need for a new OF property. Cheers, Benjamin > > And it's not just a phandle typically. > > > +- assert-reset-us: the device require reset assert time. > > > > Example: > > > > -- > > 2.7.4 > >