linux-kernel - Re: [PATCH 4.4 16/37] i2c: rcar: rework hw init

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Message-ID: <1529347590.2289.271.camel@codethink.co.uk>
Date:   Mon, 18 Jun 2018 19:46:30 +0100
From:   Ben Hutchings <ben.hutchings@...ethink.co.uk>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Cc:     stable@...r.kernel.org,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Fabrizio Castro <fabrizio.castro@...renesas.com>,
        Chris Paterson <Chris.Paterson2@...esas.com>
Subject: Re: [PATCH 4.4 16/37] i2c: rcar: rework hw init

On Tue, 2018-06-05 at 19:01 +0200, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Wolfram Sang <wsa+renesas@...g-engineering.com>
> 
> commit 2c78cdc1c06308a59d6ed4145cdba73fdeff8c0d upstream.
> 
> We don't need to init HW before every transfer since we know the HW
> state then. HW init at probe time is enough.

This part got reverted upstream by:

commit ae481cc139658e89eb3ea671dd00b67bd87f01a3
Author: Wolfram Sang <wsa+renesas@...g-engineering.com>
Date:   Tue Apr 18 20:38:35 2017 +0200

    i2c: rcar: fix resume by always initializing registers before transfer

so maybe that should go into stable (4.4 and 4.9 branches) too?

Ben.

> While here, add setting the
> clock register which belongs to init HW. Also, set MDBS bit since not
> setting it is prohibited according to the manual.
[...]

-- 
Ben Hutchings, Software Developer                         Codethink Ltd
https://www.codethink.co.uk/                 Dale House, 35 Dale Street
                                     Manchester, M1 2HF, United Kingdom