On 11/16/2011 05:16 PM, Mark Brown wrote: > On Wed, Nov 16, 2011 at 04:28:20PM +0100, Lars-Peter Clausen wrote: > >> Currently regcache checks whether a register is readable when performing a >> cached read and returns an error if not. Change this check to test whether the >> register is writable. This makes more sense, since reading from the cache when >> the register is not readable allows the operation described above, but if the >> register is not writable there shouldn't be a value for it in the cache anyway. > > This logic doesn't entirely follow - one can have registers which are > volatile but could be read once at startup. Plus... Hm? The use case here is chips which do not support readback. So we never want to fallback to a hardware read but still want to be able to do a cached read. > >> @@ -206,7 +206,7 @@ int regcache_read(struct regmap *map, >> >> BUG_ON(!map->cache_ops); >> >> - if (!regmap_readable(map, reg)) >> + if (!regmap_writeable(map, reg)) >> return -EIO; > > ...the code winds up just looking like an obvious bug. Why? If a register is not writable we won't have anything in the cache for it. So reading from the cache for a register which is not writable doesn't make any sense. -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
