From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel@caiaq.de (Daniel Mack) Date: Wed, 11 Aug 2010 12:02:10 +0200 Subject: colibri PXA320 and UCB1400 - touch screen troubles In-Reply-To: References: <201008111042.52631.marek.vasut@gmail.com> <201008111107.29839.marek.vasut@gmail.com> <20100811094543.GO17833@buzzloop.caiaq.de> Message-ID: <20100811100210.GP17833@buzzloop.caiaq.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org You dropped all recipients again and only replied to me. PLEASE DON'T DO THAT. Always keep all people in the loop, always. On Wed, Aug 11, 2010 at 01:50:43PM +0400, Yuri Ludkevich wrote: > 2010/8/11 Daniel Mack > > According to my reverse engineering, this should be GPIO4_2. > > > > Thanks a lot. > > BTW: does /sys/class/gpio/export support GPIOX_2 pins? Yes, they are aliases to the signals without the "_2" suffix. Quoting the PXA reference manual, chapter 5.3: GPIO<6_0>_2: General-Purpose IO Ports, second instantiation. The same signals as GPIO<6:0>, but they are given separate names because they are configured on separate multi-function pins. The recommended configuration is for both multi-function pin instantiations of these GPIOs not to be configured simultaneously for GPIO functionality. The preferred configuration for dual instantiation GPIO usage (that is, using both GPIO<6:0> and GPIO<6:0>_2 functions) is to configure one multi-function pin as a GPIO and the second multi-function pin instantiation for an alternate function other than a GPIO function. Configuring GPIO<6:0> to be present on two separate multi-function pins is not recommended. However, when GPIO<6:0> is configured as an output and both multi-function pin instantiations are programmed for GPIO function, the primary and secondary instantiation of the multi-function pins are both outputs from the common GGPIO<6:0> signal. However, when GPIO<6:0> is an input, the inputs from both multi-function pin instantiations are ORed together before the result is sent to the internal GPIO<6:0> input logic. HTH, Daniel