On 10/11/2013 10:59 AM, Belisko Marek wrote: > Hi Tomi, > > On Fri, Oct 11, 2013 at 10:17 AM, Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote: >> On 11/10/13 10:42, Dr. H. Nikolaus Schaller wrote: >> >>> I am not sure if there is a SPI driver for a McBSP port [1]? And to make that >>> work (reliably) and tested it might need a lot of work for us. At least I think >>> such a change (e.g. setting up clock polarity etc.) is not done in some minutes. >>> And the only feedback we have from the panel is "does not work"/"works". I.e. >>> if we are not lucky that it works immediately we have no real means to debug. >>> >>> IMHO it also gives more flexibility to board designers to choose GPIOs instead >>> of enforcing some SPI interface by the driver (and encapsulate this arguable >>> protocol in the driver). Maybe some board has 3 spare GPIOs but neither >>> McBSPs nor McSPIs available. >> >> This has been an interesting thread, I've learnt a lot =). >> >> I still think the panel driver should not handle this, but there should >> be a separate spi bitbang driver for it. >> >> I understand you're not enthusiastic going that way, as the current >> version works for you. However, when using DT, we need to think how to >> represent the hardware in the device tree data, and it has to be right >> from the beginning. >> >> That's why I won't allow representing this panel as having 4 gpios in >> the DT data, because that is not correct. The panel has 3 pins. But >> then, the panel does allow reading, which could be implemented using 4 >> gpios as you have done. This data should be in the spi-bitbang data, and >> the panel should just use the standard SPI framework. > I disagree. There are different drivers which pass in platform data > gpios (encoder-tfp410.c or encoder-tpd12s015.c) > and those must be covered by DT then. I cannot see problem why to have > for td028 panel 3 or 4 gpios defined in DT. The problem is not representing it in the devicetree, but representing it correctly. This is a SPI slave device, hence it should be presented in the devicetree as a SPI slave device and not as a platform device with 4 GPIOs. - Lars -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
