From mboxrd@z Thu Jan  1 00:00:00 1970
From: Srinivas KANDAGATLA <srinivas.kandagatla@st.com>
Subject: Re: [RFC 3/8] mfd:syscon: Introduce claim/read/write/release APIs
Date: Wed, 08 May 2013 18:42:04 +0100
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To: Mark Brown <broonie@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>, dong.aisheng@linaro.org, sameo@linux.intel.com, Rob Landley <rob@landley.net>, Grant Likely <grant.likely@secretlab.ca>, Rob Herring <rob.herring@calxeda.com>, Russell King <linux@arm.linux.org.uk>, Linus Walleij <linus.walleij@linaro.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Jiri Slaby <jslaby@suse.cz>, Stuart Menefy <stuart.menefy@st.com>, Shawn Guo <shawn.guo@linaro.org>, Olof Johansson <olof@lixom.net>, Jason Cooper <jason@lakedaemon.net>, Stephen Warren <swarren@nvidia.com>, Maxime Ripard <maxime.ripard@free-electrons.com>, Nicolas Pitre <nico@linaro.org>, Will Deacon <will.deacon@arm.com>, Dave Martin <dave.martin@linaro.org>, Marc Zyngier <marc.zyngier@arm.com>, Viresh Kumar <viresh.kumar@linaro.org>, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree-discuss@lists.ozlabs.org, linux-arm-kernel@li
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Thankyou for the comments.
On 08/05/13 16:01, Mark Brown wrote:
> On Wed, May 08, 2013 at 04:50:22PM +0200, Arnd Bergmann wrote:
>
>>> In many cases a single syconf register contains bits related to multiple
>>> devices, and therefore it need to be shared across multiple drivers at
>>> bit level. The same IP block can have different syscon mappings on
>>> different SOCs.
>> My feeling is that syscon is the wrong place for this functionality,
>> since regmap already handles (some of?) these issues. If you need
>> additional synchronization, it's probably best to extend regmap
>> as needed so other code besides syscon can take advantage of that
>> as well.
> This sounds like regmap_update_bits() ought to be all that's needed.

Ultimately the syscon_write use the regmap_update_bits, however we really want is the flexibility in using/referring the syscon registers/bits in both device-trees and non-device tree cases.

The reason for these APIs, is the extent of syscon usage is very high in ST set-top-box parts.

Without these new APIs, its very difficult to pass this information to
the drivers.

Thanks,
srini