Re: [PATCH v9 1/4] drm/i2c: tda998x: Add DT support for audio - Russell King

From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Philipp Zabel <p.zabel@pengutronix.de>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Andrew Jackson <Andrew.Jackson@arm.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Jyri Sarha <jsarha@ti.com>, Mark Brown <broonie@kernel.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH v9 1/4] drm/i2c: tda998x: Add DT support for audio
Date: Mon, 12 Jan 2015 14:04:56 +0000	[thread overview]
Message-ID: <20150112140456.GI12302@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1421071197.3081.44.camel@pengutronix.de>

On Mon, Jan 12, 2015 at 02:59:57PM +0100, Philipp Zabel wrote:
> Am Montag, den 12.01.2015, 12:25 +0000 schrieb Russell King - ARM Linux:
> > It's not quite that simple, because the SPDIF AP pins are multiplexed
> > with the I2S pins - and there is variation between chip models and
> > packages.
> >
> > So, it's probably best if port@0 is the video port, and then port@1..n
> > can describe the audio inputs, including a property which specifies
> > whether they are I2S or SPDIF, and the value to be programmed into
> > the AP enable register (which is a bit field of the AP pins which
> > should be unmasked.)  I guess we can re-use the reg= property for that
> > value, since video will always be zero.
> 
> Note that of_graph_parse_endpoint interprets the port node's reg
> property as port id. And the unit address part of the node name should
> match the first address in the reg property.

So that's not going to work very well... because the AP register is a
bitmask.

I guess we could specify a node unit and reg, which the code otherwise
ignores, and specify a philipps,ap-mask = property for the audio ports
instead.

-- 
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according to speedtest.net.
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