Re: [PATCH v7 16/24] i2c: allow adapter drivers to override the adapter locking

From: Peter Rosin <peda@axentia.se>
To: Wolfram Sang <wsa@the-dreams.de>
Cc: <linux-kernel@vger.kernel.org>, Jonathan Corbet <corbet@lwn.net>,
	Peter Korsgaard <peter.korsgaard@barco.com>,
	Guenter Roeck <linux@roeck-us.net>,
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	Lars-Peter Clausen <lars@metafoo.de>,
	Peter Meerwald <pmeerw@pmeerw.net>,
	Antti Palosaari <crope@iki.fi>,
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	Grant Likely <grant.likely@linaro.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"David S. Miller" <davem@davemloft.net>,
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	Terry Heo <terryheo@google.com>, Arnd Bergmann <arnd@arndb.de>,
	Tommi Rantala <tt.rantala@gmail.com>,
	Crestez Dan Leonard <leonard.crestez@intel.com>,
	<linux-i2c@vger.kernel.org>, <linux-doc@vger.kernel.org>,
	<linux-iio@vger.kernel.org>, <linux-media@vger.kernel.org>,
	<devicetree@vger.kernel.org>, Peter Rosin <peda@lysator.liu.se>
Subject: Re: [PATCH v7 16/24] i2c: allow adapter drivers to override the adapter locking
Date: Thu, 28 Apr 2016 23:08:26 +0200	[thread overview]
Message-ID: <470abe38-ab5f-2d0a-305b-e1a3253ce5a9@axentia.se> (raw)
In-Reply-To: <20160428205018.GA3553@katana>

On 2016-04-28 22:50, Wolfram Sang wrote:
> On Wed, Apr 20, 2016 at 05:17:56PM +0200, Peter Rosin wrote:
>> Add i2c_lock_bus() and i2c_unlock_bus(), which call the new lock_bus and
>> unlock_bus ops in the adapter. These funcs/ops take an additional flags
>> argument that indicates for what purpose the adapter is locked.
>>
>> There are two flags, I2C_LOCK_ADAPTER and I2C_LOCK_SEGMENT, but they are
>> both implemented the same. For now. Locking the adapter means that the
>> whole bus is locked, locking the segment means that only the current bus
>> segment is locked (i.e. i2c traffic on the parent side of mux is still
>> allowed even if the child side of the mux is locked.
>>
>> Also support a trylock_bus op (but no function to call it, as it is not
>> expected to be needed outside of the i2c core).
>>
>> Implement i2c_lock_adapter/i2c_unlock_adapter in terms of the new locking
>> scheme (i.e. lock with the I2C_LOCK_ADAPTER flag).
>>
>> Annotate some of the locking with explicit I2C_LOCK_SEGMENT flags.
>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
> Letting you know that I start reviewing the 2nd part of your series. Did
> the first glimpse today. Will hopefully do the in-depth part this
> weekend. One thing already:
>
>> +static void i2c_adapter_lock_bus(struct i2c_adapter *adapter, int flags)
> Shouldn't flags be unsigned?
>

Yes, obviously... I'll make that change locally and wait for the rest.

Cheers,
Peter