linux-kernel - [PATCH 0/2] ASoC: pcm3168a: Poor man's RST gpio handling

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Date:   Wed, 13 Nov 2019 14:47:32 +0200
From:   Peter Ujfalusi <peter.ujfalusi@...com>
To:     <broonie@...nel.org>, <lgirdwood@...il.com>
CC:     <alsa-devel@...a-project.org>, <kuninori.morimoto.gx@...esas.com>,
        <linus.walleij@...aro.org>, <robh+dt@...nel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH 0/2] ASoC: pcm3168a: Poor man's RST gpio handling

Hi,

when the codec RST input is connected to a GPIO it needs to be pulled high in
order to take the pcm3168a out from reset and to make it respond to register
accesses via i2c.

I have a board where one GPIO line is connected to two pcm3168a codec so runtime
handling of the RST gpio is not possible (one codec would place the other codec
to reset as well).

The only possible solution is to request the gpio with
GPIOD_FLAGS_BIT_NONEXCLUSIVE flag, ask it to be high initially and never touch
it again.

If the optinal GPIO is not described then issue the reset as the driver did.

Regards,
Peter
---
Peter Ujfalusi (2):
  bindings: sound: pcm3168a: Document optional RST gpio
  ASoC: pcm3168a: Add support for optional RST gpio handling

 .../devicetree/bindings/sound/ti,pcm3168a.txt |  7 ++++
 sound/soc/codecs/pcm3168a.c                   | 38 +++++++++++++++++--
 2 files changed, 41 insertions(+), 4 deletions(-)

-- 
Peter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki