[alsa-devel] [PATCH 1/3] ASoC: alc5623: Convert codec->hw_read to regmap_read

[Axel Lin]

2011/10/14 Mark Brown <broonie at opensource.wolfsonmicro.com>:
> On Thu, Oct 13, 2011 at 03:22:55PM +0800, Axel Lin wrote:
>> codec->hw_read is broken now, let's covert to regmap_read.
>>
>> Signed-off-by: Axel Lin <axel.lin at gmail.com>
>
> I'd rather not fix these like this because when we convert these drivers
> to use regmap directly it won't be quite so obvious what's going on and
> we'll easily introduce bugs where we start using the cached values from
> a regmap level cache.
>
> Probably the best thing here is to convert all these drivers to use
> cache_bypass to read directly through the cache - the same thing will
> then work with direct regmap usage.
>
I don't complete understand "use cache_bypass to read directly through
the cache".
Can you illustrate it?
The purpose of original implementation is to read h/w then fill the cache.
The cache is zeroed before we call alc5623_fill_cache().

Or do you mean changes like below instead of calling regmap_read directly?

diff --git a/sound/soc/codecs/alc5623.c b/sound/soc/codecs/alc5623.c
index 557b3af..43006b3 100644
--- a/sound/soc/codecs/alc5623.c
+++ b/sound/soc/codecs/alc5623.c
@@ -51,10 +51,15 @@ static void alc5623_fill_cache(struct snd_soc_codec *codec)
 {
        int i, step = codec->driver->reg_cache_step;
        u16 *cache = codec->reg_cache;
+       unsigned int val;

        /* not really efficient ... */
-       for (i = 0 ; i < codec->driver->reg_cache_size ; i += step)
-               cache[i] = codec->hw_read(codec, i);
+       codec->cache_bypass = 1;
+       for (i = 0 ; i < codec->driver->reg_cache_size ; i += step) {
+               snd_soc_read(codec, i);
+               cache[i] = val;
+       }
+       codec->cache_bypass = 0;
 }

 static inline int alc5623_reset(struct snd_soc_codec *codec)

Thanks,
Axel