From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754059AbbAGRSi (ORCPT ); Wed, 7 Jan 2015 12:18:38 -0500 Received: from fw-tnat.cambridge.arm.com ([217.140.96.140]:42833 "EHLO cam-smtp0.cambridge.arm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753180AbbAGRSg (ORCPT ); Wed, 7 Jan 2015 12:18:36 -0500 Message-ID: <54AD6A5C.60903@arm.com> Date: Wed, 07 Jan 2015 17:18:20 +0000 From: Andrew Jackson User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Jean-Francois Moine CC: Mark Brown , Russell King - ARM Linux , Dave Airlie , Jyri Sarha , "alsa-devel@alsa-project.org" , "devicetree@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v9 1/4] drm/i2c: tda998x: Add DT support for audio References: <0084acea5a3475a77531d6a77483f36d3469111a.1420628786.git.moinejf@free.fr> <54AD4511.30702@arm.com> <20150107180825.52334d4f@armhf> In-Reply-To: <20150107180825.52334d4f@armhf> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/07/15 17:08, Jean-Francois Moine wrote: > On Wed, 07 Jan 2015 14:39:13 +0000 > Andrew Jackson wrote: > >>> + - audio-ports: must contain one or two values selecting the source >>> + in the audio port. >>> + The source type is given by the corresponding entry in >>> + the audio-port-names property. >> >> I think that this entry might benefit from a little more explanation. >> The value specified here selects which pins on the chip provide the >> audio input doesn't it? In the outline datasheet that I have these are >> listed in table 17: >> >> Audio port Input configuration >> S/PDIF I2S-bus >> AP0 - WS (word select) >> AP1 S/PDIF input I2S-bus channel 0 >> AP2 S/PDIF input I2S-bus channel 1 >> AP3[1] I2S-bus channel 2 >> AP4[1] I2S-bus channel 3 >> ACLK - SCK (I2S-bus clock) >> >> [1] Depending on package. > > Your table is close to the one in the TDA9983B documentation I have, > but the pins are not exactly the same: > > AP0 WS (word select) > AP1 I2S-bus port 0 > AP2 I2S-bus port 1 > AP3 I2S-bus port 2 > AP4 I2S-bus port 3 > AP5 MCLK (master clock for S/PDIF) > AP6 S/PDIF input > AP7 AUX (internal test) > ACLK SCK (I2S-bus clock) > > That's why I did not know clearly why I had to set AP2 for S/PDIF input > and (AP0 + AP1) for I2S input in the Cubox. > > Then, the only more explanation I could give is "have a look at the > audio input format and at the register 0x1e page 0 in the documentation > of the TDA998x chip". > > BTW, the tda998x driver supports only the TDA9989, TDA19988 and > TDA19989 chips. If the TDA9983B would be supported, the audio port > definitions would be of no use. > > So, what would you see as an explanation? > I understand your difficulty! I was just wanting something to clarify the meaning of the value without reference to the driver source. You could add something like this to your existing explanation: "The value describes which audio input pins are selected; this varies depending on chip type so consult the section on audio port configuration in the relevant datasheet.". Andrew