Re: [PATCH 6/6 v5] regmap: Incorporate the regcache core into regmap

Mark Brown
2011-09-19T16:14:04Z

On Mon, Sep 19, 2011 at 05:57:49PM +0200, Lars-Peter Clausen wrote:
> On 09/19/2011 03:34 PM, Dimitris Papastamos wrote:

> > + if (!map->cache_bypass) {
> > + ret = regcache_write(map, reg, val);
> > + if (!ret || map->cache_only)
> > + return 0;

> The hw write shouldn't be skipped if the cache write is successful. We should
> only exit here if cache_only is set.

There's a couple of other issues too. I've already got the following
patch for this one locally:

--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -304,7 +304,9 @@ static int _regmap_write(struct regmap *map,
unsigned int re

if (!map->cache_bypass) {
ret = regcache_write(map, reg, val);
- if (!ret || map->cache_only)
+ if (ret != 0)
+ return ret;
+ if (map->cache_only)
return 0;
}

> I also wonder if we should pass the return value of regcache_write on to the
> caller if cache_only is set.

Yup.

> Btw. what should happen if both cache_bypass and cache_only are set? Or is that
> an invalid configuration?

That's not sensible. Probably BUG_ON().

> > @@ -428,6 +446,14 @@ int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)

> > mutex_lock(&map->lock);

> > + if (!map->cache_bypass) {
> > + ret = regcache_read(map, reg, val);
> > + if (!ret) {
> > + mutex_unlock(&map->lock);
> > + return 0;
> > + }
> > + }

> This should go into _regmap_read. Otherwise regmap_update_bits will always use
> a hw read.

Yup, got that too.

> Also if cache_only is set I guess we shouldn't fallback to a hw read.

Probably. Cache only is *mostly* there for write side stuff, but it'd
be useful to add this. I've got a patch to do this.