>> -----Original Message-----
>> From: Nori, Sekhar
>> Sent: Thursday, October 11, 2012 8:25 AM
>> To: Karicheri, Muralidharan
>> Cc: mturque...@linaro.org; a...@arndb.de; a...@linux-foundation.org;
>> shawn....@linaro.org; rob.herr...@calxeda.com; linus.wall...@linaro.org;
>> viresh.li...@gmail.com; linux-kernel@vger.kernel.org; Hilman, Kevin;
>> li...@arm.linux.org.uk; davinci-linux-open-sou...@linux.davincidsp.com;
>> linux-arm-
>> ker...@lists.infradead.org; linux-keyst...@list.ti.com - Linux developers
>> for Keystone
>> family of devices (May contain non-TIers); linux-c6x-...@linux-c6x.org;
>> Chemparathy,
>> Cyril
>> Subject: Re: [PATCH v2 09/13] ARM: davinci - update the dm644x soc code to
>> use
>> common clk drivers
>>
>> Murali,
>>
>> On 9/26/2012 11:40 PM, Murali Karicheri wrote:
>> > The clock tree for dm644x is defined using the new structure davinci_clk.
>> > The SoC specific code re-uses clk-fixed-rate, clk-divider and clk-mux
>> > drivers in addition to the davinci specific clk drivers,
>> > clk-davinci-pll and clk-davinci-psc. Macros are defined to define the
>> > various clocks in the SoC.
>> >
>> > Signed-off-by: Murali Karicheri <m-kariche...@ti.com>
>>
>> You have chosen to keep all clock related data in platform files while using
>> the common
>> clock framework to provide just the infrastructure. If you look at how mxs
>> and spear
>> have been migrated, they have migrated the soc specific clock data to
>> drivers/clk as well.
>> See "drivers/clk/spear/spear3xx_clock.c" or "drivers/clk/mxs/clk-imx23.c
I have to disagree on this one. I had investigated these code already and came
up with a way that we can re-use code across all of the davinci platforms as
well as other architectures that re-uses the clk hardware IPs. spear3xx_clock.c
has initialization code for each of the platforms and so is the case with
imx23.c. By using platform_data approach, we are able to define clks for each
of the SoC and then use davinci_common_clk_init() to do initialize the clk
drivers based on platform data. Later once we migrate to device tree,
davinci_common_clk_init() will go way and also the clk structures defined in
the SoC file. I have prototyped this on one of the device that I am working on.
davinci_common_clk_init() will be replaced with a of_davinci_clk_init() that
will use device tree to get all of the platform data for the clk providers and
do the initialization based on that. See highbank_clocks_init() in
clk-highbank.c. I have used this model for device
tree based clk initialization.
So it make sense to keep the design the way it is. Otherwise we will end up
writing dm644x_clk_init(), dm355_clk_init(), etc for each of the platforms and
these code will get thrown away once we migrate to
device tree.
>>". I feel the
>> latter way is better and I also think it will simplify some of the look-up
>> infrastructure you
>> had to build. This will also help some real code reduction from
>> arch/arm/mach-davinci/.
>>
The look-up infrastructure is pretty much re-use of the existing code base in
SoC specific file. About code reduction, I can't say I agree, as we need to add
platform_specific clock initialization code if we follow spear3xx_clock.c model
and end up probably adding more code. SoC specific file (for example dm644x.c)
has only data structures and all of SoC will re-use davinci_common_clk_init()
to do the initialization. So I am not sure how you conclude we will have code
reduction?
- Murali
>> Thanks,
>> Sekhar
N�����r��y����b�X��ǧv�^�){.n�+����{����zX����ܨ}���Ơz�&j:+v�������zZ+��+zf���h���~����i���z� �w���?�����&�)ߢf��^jǫy�m��@A�a���
0��h���i
