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From: Mike Looijmans <mike.looijmans@topic.nl>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, michal.simek@xilinx.com,
	linux-i2c@vger.kernel.org, Vladimir Zapolskiy <vz@mleia.com>,
	soren.brinkmann@xilinx.com
Subject: Re: [PATCH] i2c: i2c-cadence: Don't register the adapter until it's ready
Date: Fri, 13 Jan 2017 15:52:00 +0100	[thread overview]
Message-ID: <5d1b0fda-38e7-c4bd-46de-318507525c8b@topic.nl> (raw)
In-Reply-To: <20170113083727.GB1446@katana>

On 13-01-17 09:37, Wolfram Sang wrote:
>
>> I would argue that the "info" message means "the I2C adapter is ready for
>> transaction now, and we'll start initializing devices on the bus". That is
>> the case before it calls i2c_add_adapter().
>
> I know what you mean, but i2c_add_adapter does more, and it can fail
> because the adapter is *not* ready to transfer. Seeing the success
> message before is also confusing.
>
>> When i2c_add_adapter() runs, it will start probing devices on the bus. This
>> yields very confusing output, as it will output things in a reversed order:
>>
>> - device X on I2C bus
>> - device Y on I2C bus
>> - cdns-i2c ff030000.i2c: 100 kHz mmio ff030000 irq 197
>
> I agree. That being said, somewhen I started working on moving such
> messages into the core to save string space and have consistent output.
> Then, we can print at the proper time.
>
> So, until then, we should be consistent with the other driver, I'd say.

Makes sense.

I'll create a v2 patch to just move the i2c_add_adapter to after writing the 
configuration registers, and leave the dmesg output as is.

Thanks for reviewing,
Mike.


Kind regards,

Mike Looijmans
System Expert

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      reply	other threads:[~2017-01-13 14:52 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-05 10:47 [PATCH] i2c: i2c-cadence: Don't register the adapter until it's ready Mike Looijmans
2017-01-06 21:34 ` Vladimir Zapolskiy
2017-01-12 19:22   ` Wolfram Sang
2017-01-13  6:40   ` Mike Looijmans
2017-01-13  8:37     ` Wolfram Sang
2017-01-13 14:52       ` Mike Looijmans [this message]

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