touch screen ads7846/7843 devicetree support

touch screen ads7846/7843 devicetree support

[Thomas Chou]

Hi Mike,

We need devicetree support on ads7846/7843 touch screen driver. Do you 
have plan on it? We are moving to devicetree on nios2, so do arm/mips/x86.

Best regards,
Thomas

Re: touch screen ads7846/7843 devicetree support

[Mike Frysinger]

On Thu, Jan 27, 2011 at 01:10, Thomas Chou wrote:
> We need devicetree support on ads7846/7843 touch screen driver. Do you have
> plan on it? We are moving to devicetree on nios2, so do arm/mips/x86.

what part are you using exactly ?
-mike

Re: touch screen ads7846/7843 devicetree support

[Thomas Chou]

On 01/27/2011 02:18 PM, Mike Frysinger wrote:
> On Thu, Jan 27, 2011 at 01:10, Thomas Chou wrote:
>> We need devicetree support on ads7846/7843 touch screen driver. Do you have
>> plan on it? We are moving to devicetree on nios2, so do arm/mips/x86.
>
> what part are you using exactly ?
> -mike
>

ad7843 is used in a popular nios2 dev kit, NEEK.

- Thomas

Re: touch screen ads7846/7843 devicetree support

[Hennerich, Michael]

Thomas Chou wrote on 2011-01-27:
> On 01/27/2011 02:18 PM, Mike Frysinger wrote:
>> On Thu, Jan 27, 2011 at 01:10, Thomas Chou wrote:
>>> We need devicetree support on ads7846/7843 touch screen driver. Do
>>> you have plan on it? We are moving to devicetree on nios2, so do
> arm/mips/x86.
>>
>> what part are you using exactly ?
>> -mike
>>
>
> ad7843 is used in a popular nios2 dev kit, NEEK.

This driver is a SPI bus client driver. PPC is using devicetree for ages now,
and they don't have problems instantiating this or any other SPI bus driver.

What special needs do you have?

Greetings,
Michael

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Re: [uclinux-dist-devel] touch screen ads7846/7843 devicetree support

[Thomas Chou]

Dear Michael,

On 01/27/2011 08:24 PM, Hennerich, Michael wrote:
> This driver is a SPI bus client driver. PPC is using devicetree for ages now,
> and they don't have problems instantiating this or any other SPI bus driver..

Thanks for the pointer. I looked in powerpc dir and found one usage in

linux-2.6/arch/powerpc/platforms/512x/pdm360ng.c

I will try to follow it.

Best regards,
Thomas

Re: [uclinux-dist-devel] touch screen ads7846/7843 devicetree support

[Grant Likely]

On Thu, Jan 27, 2011 at 12:24:01PM +0000, Hennerich, Michael wrote:
> Thomas Chou wrote on 2011-01-27:
> > On 01/27/2011 02:18 PM, Mike Frysinger wrote:
> >> On Thu, Jan 27, 2011 at 01:10, Thomas Chou wrote:
> >>> We need devicetree support on ads7846/7843 touch screen driver. Do
> >>> you have plan on it? We are moving to devicetree on nios2, so do
> > arm/mips/x86.
> >>
> >> what part are you using exactly ?
> >> -mike
> >>
> >
> > ad7843 is used in a popular nios2 dev kit, NEEK.
> 
> This driver is a SPI bus client driver. PPC is using devicetree for ages now,
> and they don't have problems instantiating this or any other SPI bus driver.

However, the method used is by applying a heuristic (of_modalias_node)
which tries to name the device in a way that will match an existing
device driver.  It works for a lot of spi drivers, but it isn't
always reliable.

Alternatively, if of_match_table is populated in the spi_driver, then
the normal device tree match behaviour will always work.

g.

Re: [uclinux-dist-devel] touch screen ads7846/7843 devicetree support

[Thomas Chou]

On 02/03/2011 12:03 AM, Grant Likely wrote:
> On Thu, Jan 27, 2011 at 12:24:01PM +0000, Hennerich, Michael wrote:
>> Thomas Chou wrote on 2011-01-27:
>>> On 01/27/2011 02:18 PM, Mike Frysinger wrote:
>>>> On Thu, Jan 27, 2011 at 01:10, Thomas Chou wrote:
>>>>> We need devicetree support on ads7846/7843 touch screen driver. Do
>>>>> you have plan on it? We are moving to devicetree on nios2, so do
>>> arm/mips/x86.
>>>>
>>>> what part are you using exactly ?
>>>> -mike
>>>>
>>>
>>> ad7843 is used in a popular nios2 dev kit, NEEK.
>>
>> This driver is a SPI bus client driver. PPC is using devicetree for ages now,
>> and they don't have problems instantiating this or any other SPI bus driver.
>
> However, the method used is by applying a heuristic (of_modalias_node)
> which tries to name the device in a way that will match an existing
> device driver.  It works for a lot of spi drivers, but it isn't
> always reliable.
>
> Alternatively, if of_match_table is populated in the spi_driver, then
> the normal device tree match behaviour will always work.

Thanks. The driver did match with the heuristic. But it needs to 
determine pen state. I will try to bind a gpio node in dts.

linux/spi/ads7846.h

int	gpio_pendown;		/* the GPIO used to decide the pendown
				 * state if get_pendown_state == NULL
				 */

- Thomas

Re: [uclinux-dist-devel] touch screen ads7846/7843 devicetree support

[Barry Song]

2011/2/3 Grant Likely <grant.likely@secretlab.ca>:
> On Thu, Jan 27, 2011 at 12:24:01PM +0000, Hennerich, Michael wrote:
>> Thomas Chou wrote on 2011-01-27:
>> > On 01/27/2011 02:18 PM, Mike Frysinger wrote:
>> >> On Thu, Jan 27, 2011 at 01:10, Thomas Chou wrote:
>> >>> We need devicetree support on ads7846/7843 touch screen driver. Do
>> >>> you have plan on it? We are moving to devicetree on nios2, so do
>> > arm/mips/x86.
>> >>
>> >> what part are you using exactly ?
>> >> -mike
>> >>
>> >
>> > ad7843 is used in a popular nios2 dev kit, NEEK.
>>
>> This driver is a SPI bus client driver. PPC is using devicetree for ages now,
>> and they don't have problems instantiating this or any other SPI bus driver.
>
> However, the method used is by applying a heuristic (of_modalias_node)
> which tries to name the device in a way that will match an existing
> device driver.  It works for a lot of spi drivers, but it isn't
> always reliable.
>
> Alternatively, if of_match_table is populated in the spi_driver, then
> the normal device tree match behaviour will always work.

not like i2c_driver and platform_driver, it is really difficult to
find many spi client drivers using device tree fo the moment. most spi
boards still use spi_board_info to register spi client. these spi
client drivers do work well with spi host based on device tree at most
cases. the ideal spi client should be a child node of spi host in
device tree, then use of_match_table to get probed.
i am working on ads7846 as an example for our team to use device tree
in spi client drivers and will send a patch.

BTW, is ads7846 from TI? or am i wrong? why is this question posted in
ADI' maillist?

>
> g.
>
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Re: [uclinux-dist-devel] touch screen ads7846/7843 devicetree support

[Mike Frysinger]

On Thu, Jun 9, 2011 at 02:07, Barry Song wrote:
> BTW, is ads7846 from TI? or am i wrong? why is this question posted in
> ADI' maillist?

ads7846 is a TI part, but the driver supports more than just that part
-mike