Re: [alsa-devel] [PATCH 1/2] regmap: cache: Fix regcache_sync_block for non-autoincrementing devices

[Jarkko Nikula]

On 08/26/2014 05:21 PM, Takashi Iwai wrote:
> At Tue, 26 Aug 2014 17:03:12 +0300,
> Jarkko Nikula wrote:
> > Commit 75a5f89f635c ("regmap: cache: Write consecutive registers in a single
> > block write") expected that autoincrementing writes are supported if
> > hardware has a register format which can support raw writes.
> >
> > This is not necessarily true and thus for instance rbtree sync can fail when
> > there is need to sync multiple consecutive registers but block write to
> > device fails due not supported autoincrementing writes.
> >
> > Fix this by spliting raw block sync to series of single register writes for
> > devices that don't support autoincrementing writes.
> Wouldn't it suffice to correct regmap_can_raw_write() to return false
> if map->use_single_rw is set?
I don't know. I was thinking that also but was unsure about it since 
regcache_sync_block_raw() and regcache_sync_block_single() code paths 
use different regmap write functions. regcache_sync_block_raw() ends up 
calling _regmap_raw_write() which takes care of page select operation 
when needed and regcache_sync_block_single() uses _regmap_write() which 
doesn't.

Which makes me thinking should the regcache_sync_block_single() also use 
_regmap_raw_write() in order to take care of page selects?

--
Jarkko
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