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

Lars-Peter Clausen
2011-09-19T15:58:29Z

On 09/19/2011 03:34 PM, Dimitris Papastamos wrote:
> This patch incorporates the regcache core code into regmap. All previous
> patches have been no-ops essentially up to this point.
>
> The bulk read operation is not supported by regcache at the moment. This
> will be implemented incrementally.
>
> Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
> Tested-by: Lars-Peter Clausen <lars@metafoo.de>

Hi

Two issues with this version.

> [...]
> @@ -290,6 +302,12 @@ static int _regmap_write(struct regmap *map, unsigned int reg,
> int ret;
> BUG_ON(!map->format.format_write && !map->format.format_val);
>
> + 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.

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

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

> + }
> +
> trace_regmap_reg_write(map->dev, reg, val);
>
> if (map->format.format_write) {
> @@ -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.

Also if cache_only is set I guess we shouldn't fallback to a hw read.
> +
> ret = _regmap_read(map, reg, val);
>
> mutex_unlock(&map->lock);