linux-kernel - Re: [RESEND PATCH v1 6/6] i2c: i2c-stm32f7: Implement I2C recovery mechanism

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Message-ID: <2672947b-46b2-7bd7-ac13-501db8bde72b@st.com>
Date:   Mon, 19 Mar 2018 09:51:07 +0100
From:   Pierre Yves MORDRET <pierre-yves.mordret@...com>
To:     Wolfram Sang <wsa@...-dreams.de>
CC:     Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        <linux-i2c@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND PATCH v1 6/6] i2c: i2c-stm32f7: Implement I2C recovery
 mechanism

Yes. Recovery mechanism is triggered whenever a busy line is detected.
This busy state can be checked by sw when either SDA or SCL is low: a bit is set
by Hw for this purpose.
On busy state I2C is reconfigured and lines are released the time of recovery.

Regards
On 03/17/2018 09:47 PM, Wolfram Sang wrote:
> On Mon, Mar 12, 2018 at 11:53:43AM +0100, Pierre-Yves MORDRET wrote:
>> Feature prevents I2C lock-ups. Mechanism resets I2C state machine
>> and releases SCL/SDA signals but preserves I2C registers.
> 
> Does it release SDA when held down by the slave? Because that is what
> the recovery mechanism is for.
>