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Date:   Mon, 26 Mar 2018 15:39:43 -0700
From:   Dmitry Torokhov <dmitry.torokhov@gmail.com>
To:     Rob Herring <robh@kernel.org>
Cc:     Mark Jonas <mark.jonas@de.bosch.com>,
        Mark Rutland <mark.rutland@arm.com>,
        linux-input@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, hs@denx.de,
        Zhu Yi <yi.zhu5@cn.bosch.com>
Subject: Re: [PATCH] Input: add bu21029 touch driver
Message-ID: <20180326223943.GC204225@dtor-ws>
References: <1521651874-15379-1-git-send-email-mark.jonas@de.bosch.com>
 <20180326222426.wbdjlyfy7yyan7fc@rob-hp-laptop>
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On Mon, Mar 26, 2018 at 05:24:26PM -0500, Rob Herring wrote:
> On Wed, Mar 21, 2018 at 06:04:34PM +0100, Mark Jonas wrote:
> > From: Zhu Yi <yi.zhu5@cn.bosch.com>
> > 
> > Add the ROHM BU21029 resistive touch panel controller
> > support with i2c interface.
> > 
> > Signed-off-by: Zhu Yi <yi.zhu5@cn.bosch.com>
> > Signed-off-by: Mark Jonas <mark.jonas@de.bosch.com>
> > Reviewed-by: Heiko Schocher <hs@denx.de>
> > ---
> >  .../bindings/input/touchscreen/bu21029.txt         |  30 ++
> >  drivers/input/touchscreen/Kconfig                  |  12 +
> >  drivers/input/touchscreen/Makefile                 |   1 +
> >  drivers/input/touchscreen/bu21029_ts.c             | 456 +++++++++++++++++++++
> >  4 files changed, 499 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/input/touchscreen/bu21029.txt
> >  create mode 100644 drivers/input/touchscreen/bu21029_ts.c
> > 
> > diff --git a/Documentation/devicetree/bindings/input/touchscreen/bu21029.txt b/Documentation/devicetree/bindings/input/touchscreen/bu21029.txt
> > new file mode 100644
> > index 0000000..7b61602
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/input/touchscreen/bu21029.txt
> > @@ -0,0 +1,30 @@
> > +* Rohm BU21029 Touch Screen Controller
> > +
> > +Required properties:
> > + - compatible              : must be "rohm,bu21029"
> > + - reg                     : i2c device address of the chip
> 
> What the valid value(s)?
> 
> > + - interrupt-parent        : the phandle for the gpio controller
> > + - interrupts              : (gpio) interrupt to which the chip is connected
> > + - reset-gpios             : gpio pin to reset the chip
> 
> Active high or low?
> 
> > + - rohm,x-plate-ohms       : x-plate resistance in ohms
> 
> IIRC, we have a standard touchscreen property for this?

I do not think so: it is specific for resistive touchscreens, whereas
"standard" touchscreen properties are technology-independent ones (size,
rotation, etc).

> 
> > +
> > +Optional properties:
> > + - touchscreen-max-pressure: maximum pressure value
> > +
> > +Example:
> > +
> > +	&i2c1 {
> > +		/* ... */
> > +
> > +		bu21029: bu21029@40 {
> > +			compatible = "rohm,bu21029";
> > +			reg = <0x40>;
> > +			interrupt-parent = <&gpio1>;
> > +			interrupts = <4 IRQ_TYPE_EDGE_FALLING>;
> > +			reset-gpios = <&gpio6 16 GPIO_ACTIVE_LOW>;
> > +			rohm,x-plate-ohms = <600>;
> > +			touchscreen-max-pressure = <4095>;
> > +		};
> > +
> > +		/* ... */
> > +	};

-- 
Dmitry