From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:50801 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752314Ab2G3Hjv (ORCPT ); Mon, 30 Jul 2012 03:39:51 -0400 Message-ID: <50163A3B.6080807@iki.fi> Date: Mon, 30 Jul 2012 10:39:39 +0300 From: Antti Palosaari MIME-Version: 1.0 To: poma CC: linux-media@vger.kernel.org Subject: Re: GPIO interface between DVB sub-drivers (bridge, demod, tuner) References: <4FFF327A.9080300@iki.fi> <5008B7B0.1020602@iki.fi> <5015A947.4040005@gmail.com> In-Reply-To: <5015A947.4040005@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-media-owner@vger.kernel.org List-ID: On 07/30/2012 12:21 AM, poma wrote: > On 07/20/2012 03:43 AM, Antti Palosaari wrote: >> On 07/13/2012 12:07 AM, Steven Toth wrote: >>> On Thu, Jul 12, 2012 at 4:49 PM, Steven Toth >>> wrote: >>>> Nobody understands the relationship between the bridge and the >>>> sub-component as well as the bridge driver. The current interfaces are >>>> limiting in many ways. We solve that today with rather ugly 'attach' >>>> structures that are inflexible, for example to set gpios to a default >>>> state. >>>> Then, once that interface is attached, the bridge effectively loses >>>> most of >>>> the control to the tuner and/or demod. The result is a large disconnect >>>> between the bridge and subcomponents. >>>> >>>> Why limit any interface extension to GPIOs? Why not make something a >>>> little more flexible so we can pass custom messages around? >> >>>> What did you ever decide about the enable/disable of the LNA? And, how >>>> would the bridge do that in your proposed solution? Via the proposed >>>> GPIO >>>> interface? >> >> GPIO / LNA is ready, see following patches: >> add LNA support for DVB API >> cxd2820r: use Kernel GPIO for GPIO access >> em28xx: implement FE set_lna() callback >> >> from: >> http://git.linuxtv.org/anttip/media_tree.git/shortlog/refs/heads/dvb_core >> >> Kernel GPIOs were quite easy to implement and use - when needed >> knowledge was gathered after all the testing and study. I wonder why >> none was done that earlier for DVB... >> >> It also offer nice debug/devel feature as you can mount those GPIOs via >> sysfs and use directly. >> > > Above mentioned GPIO functionality must be implemented in driver itself > to use /sys/class/gpio/… sysfs interface, right? > It is not enough to build kernel with CONFIG_GENERIC_GPIO=y, > CONFIG_GPIOLIB=y, CONFIG_GPIO_SYSFS, right? You will need to implement callbacks for gpiolib. sysfs interface is then get for free. regards Antti -- http://palosaari.fi/