[PATCH] pinctrl: bcm2835: make use of of_property_read_u32_index()
linux at prisktech.co.nz
Thu Mar 28 02:18:36 EDT 2013
On Wed, 2013-03-27 at 23:09 -0600, Stephen Warren wrote:
> Use the new standard API of_property_read_u32_index() instead of open-
> coding it.
> Signed-off-by: Stephen Warren <swarren at wwwdotorg.org>
> Note: This depends on the proposed patch "of: Add support for reading
> a u32 from a multi-value property" by Tony Prisk.
> BTW, I realized why I didn't create that standard API, but wrote custom
> prop_u32() instead; the code has already looked up the properties, and
> validated their length, so prop_u32() can simply index into the property
> data, whereas of_property_read_u32_index() needs to go search for the
> property and re-validate it every time, so there's a bunch more overhead.
> It also means duplicating the property name, although I could use a
> define for that. I'm not entirely convinced that using this standard API
> is a win in this case. LinusW, Tony, what do you think?
When I was writing the function I had a similar thought about the fact
we need to work out the length first, which as you mentioned, requires
all the prior work on the property anyway.
I didn't bring it up, because I thought someone might say 'hey, you
should add a function to get the count as well' :)
In both the brcm and vt8500 use cases, we will have the issue of
multiple lookups on the same property using 'generic' functions. Price
we have to pay for generic code?
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