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SubjectRe: [PATCH v2 2/5] Documentation: Detail permitted DT properties for the imx6ul_tsc
On Fri, Aug 21, 2015 at 08:30:16AM +0000, Chen Bough wrote:
> Hi Markus,
>
> > -----Original Message-----
> > From: Markus Pargmann [mailto:mpa@pengutronix.de]
> > Sent: Wednesday, August 19, 2015 1:55 PM
> > To: Chen Haibo-B51421
> > Cc: robh+dt@kernel.org; pawel.moll@arm.com; mark.rutland@arm.com;
> > ijc+devicetree@hellion.org.uk; galak@codeaurora.org; shawnguo@kernel.org;
> > kernel@pengutronix.de; linux@arm.linux.org.uk; dmitry.torokhov@gmail.com;
> > devicetree@vger.kernel.org; sbranden@broadcom.com; arnd@arndb.de;
> > mchehab@osg.samsung.com; christian.gmeiner@gmail.com;
> > scott.liu@emc.com.tw; linux-kernel@vger.kernel.org; hdegoede@redhat.com;
> > jonathar@broadcom.com; benjamin.tissoires@redhat.com;
> > hans.verkuil@cisco.com; hadess@hadess.net; linux-input@vger.kernel.org;
> > geert@linux-m68k.org; sebastien.szymanski@armadeus.com;
> > mamlinav@gmail.com; linux-arm-kernel@lists.infradead.org
> > Subject: Re: [PATCH v2 2/5] Documentation: Detail permitted DT properties
> > for the imx6ul_tsc
> >
> > Hi,
> >
> > On Tue, Jul 28, 2015 at 05:58:38PM +0800, Haibo Chen wrote:
> > > Here we apply required documentation for the imx6ul touch screen
> > > controller driver which describe available properties and how to use
> > > them.
> > >
> > > Signed-off-by: Haibo Chen <haibo.chen@freescale.com>
> > > ---
> > > .../bindings/input/touchscreen/imx6ul_tsc.txt | 36
> > ++++++++++++++++++++++
> > > 1 file changed, 36 insertions(+)
> > > create mode 100644
> > > Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt
> > >
> > > diff --git
> > > a/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt
> > > b/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.txt
> > > new file mode 100644
> > > index 0000000..ac41c32
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/input/touchscreen/imx6ul_tsc.t
> > > +++ xt
> > > @@ -0,0 +1,36 @@
> > > +* Freescale i.MX6UL Touch Controller
> > > +
> > > +Required properties:
> > > +- compatible: must be "fsl,imx6ul-tsc".
> > > +- reg: this touch controller address and the ADC2 address.
> > This suggests that this driver is using a unit ADC2. Which also means
> > that there are more than one ADC which are probably identical?
> >
> > Shouldn't these ADCs be properly described by their own device nodes
> > instead of these two register ranges, two interrupts and two clocks?
> >
> > Is 'ADC2' usable without tsc? Then ADC1/ADC2 should perhaps get a proper
> > IIO driver.
>
> For i.MX6UL, there are two ADC. ADC1 is a normal ADC, and ADC2 can only works for
> TSC, the channels of ADC2 are connected to TSC directly. TSC and ADC2 should work
> together as a touch screen controller.

But as I understand these are two different units. Wouldn't it be better
to abstract it that way in the DT?

Best regards,

Markus

>
> For ADC1, it share the driver vf610_adc.c (drivers/iio/adc/vf610_adc.c).
>
> Best Regards
>
> Haibo
>
> >
> > Unfortunately I don't have the reference manual to have a look how this
> > all works.
> >
> > Best regards,
> >
> > Markus
> >
> > > +- interrupts: the interrupt of this touch controller and ADC2.
> > > +- clocks: the root clock of touch controller and ADC2.
> > > +- clock-names; must be "tsc" and "adc".
> > > +- xnur-gpio: the X- gpio this controller connect to.
> > > + This xnur-gpio returns to high once the finger leave the touch
> > > +screen (The
> > > + last touch event the touch controller capture).
> > > +
> > > +Optional properties:
> > > +- measure-delay-time: the value of measure delay time.
> > > + Before X-axis or Y-axis measurement, the screen need some time
> > > +before
> > > + even potential distribution ready.
> > > + This value depends on the touch screen.
> > > +- pre-charge-time: the touch screen need some time to precharge.
> > > + This value depends on the touch screen.
> > > +
> > > +Example:
> > > + tsc: tsc@02040000 {
> > > + compatible = "fsl,imx6ul-tsc";
> > > + reg = <0x02040000 0x4000>, <0x0219c000 0x4000>;
> > > + interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>,
> > > + <GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>;
> > > + clocks = <&clks IMX6UL_CLK_IPG>,
> > > + <&clks IMX6UL_CLK_ADC2>;
> > > + clock-names = "tsc", "adc";
> > > + pinctrl-names = "default";
> > > + pinctrl-0 = <&pinctrl_tsc>;
> > > + xnur-gpio = <&gpio1 3 GPIO_ACTIVE_HIGH>;
> > > + measure-delay-time = <0xfff>;
> > > + pre-charge-time = <0xffff>;
> > > + status = "okay";
> > > + };
> > > --
> > > 1.9.1
> > >
> > >
> > >
> >
> > --
> > Pengutronix e.K. |
> > |
> > Industrial Linux Solutions | http://www.pengutronix.de/
> > |
> > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0
> > |
> > Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555
> > |

--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |[unhandled content-type:application/pgp-signature]
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