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

On 02/03/2011 12:03 AM, Grant Likely wrote:

On Thu, Jan 27, 2011 at 12:24:01PM +0000, Hennerich, Michael wrote:

quoted

Thomas Chou wrote on 2011-01-27:

quoted

On 01/27/2011 02:18 PM, Mike Frysinger wrote:

quoted

On Thu, Jan 27, 2011 at 01:10, Thomas Chou wrote:

quoted

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.

quoted

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