Re: [PATCHv4 2/5] Input: edt-ft5x06: Add DT support

From: "Lothar Waßmann" <LW@KARO-electronics.de>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Fugang Duan <B38611@freescale.com>,
	"grant.likely@linaro.org" <grant.likely@linaro.org>,
	Henrik Rydberg <rydberg@euromail.se>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Jingoo Han <jg1.han@samsung.com>,
	Kumar Gala <galak@codeaurora.org>,
	Pawel Moll <Pawel.Moll@arm.com>, Rob Herring <robh+dt@kernel.org>,
	Rob Landley <rob@landley.net>,
	Sachin Kamat <sachin.kamat@linaro.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
	"linux-input@vger.kernel.org" <linux-input@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Simon Budig <simon.budig@kernelconcepts.de>
Subject: Re: [PATCHv4 2/5] Input: edt-ft5x06: Add DT support
Date: Thu, 20 Mar 2014 12:40:55 +0100	[thread overview]
Message-ID: <20140320124055.53d469e7@ipc1.ka-ro> (raw)
In-Reply-To: <20140320093719.GB14420@e106331-lin.cambridge.arm.com>

Hi,

Mark Rutland wrote:
> On Wed, Mar 19, 2014 at 01:09:20PM +0000, Lothar Waßmann wrote:
> > 
> > Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
> > ---
> >  .../bindings/input/touchscreen/edt-ft5x06.txt      |   41 ++++++
> >  drivers/input/touchscreen/edt-ft5x06.c             |  144 +++++++++++++++-----
> >  2 files changed, 154 insertions(+), 31 deletions(-)
> >  create mode 100644 Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
> > new file mode 100644
> > index 0000000..e5adc76
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/input/touchscreen/edt-ft5x06.txt
> > @@ -0,0 +1,41 @@
> > +FocalTech EDT-FT5x06 Polytouch driver
> > +=====================================
> > +
> > +Required properties:
> > + - compatible:  "edt,edt-ft5x06"
> 
> Is the 'x' part of a particular product name, or is this a class of
> devices?
> 
The FT5x06 datasheet lists 3 variants for different panel sizes.
I'll add distinct compatible strings for those chips, though their SW
interface is (currently) identical:
|Required properties:
| - compatible:  "edt,edt-ft5206", "edt,edt-ft5x06"
|           or:  "edt,edt-ft5306", "edt,edt-ft5x06"
|           or:  "edt,edt-ft5406", "edt,edt-ft5x06"


> > + - reg:         I2C slave address of the chip (0x38)
> > + - interrupt-parent: a phandle pointing to the interrupt controller
> > +                     serving the interrupt for this chip
> > + - interrupts:       interrupt specification for this chip
> 
> How many? What are they for?
>
I'll change it to: 
| - interrupts:       interrupt specification for the touchdetect
|                     interrupt

> > + - report_rate: allows setting the report rate in the range from 3 to
> > +                14.
> 
> However, why can the kernel not decide the report rate? This doesn't
> sound like something that needs to vary per-board.
> 
> Also, s/_/-/ in property names, please.
> 
OK, I'll drop the property, which also simplyfies the code a bit.

> > +#define EDT_GET_PROP(name, reg) {					\
> > +	const u32 *prop = of_get_property(np, #name, NULL);		\
> > +	if (prop)							\
> > +		edt_ft5x06_register_write(tsdata, reg, be32_to_cpu(*prop)); \
> > +}
> 
> Use of_property_read_u32, it'll handle endianness conversion for you.
> 
> Use of of_get_property is almost always wrong.
> 
Sure.


Lothar Waßmann
-- 
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