Re: [PATCH] power: supply: Use an rbtree rather than flat register cache

[Dmitry Osipenko <digetx@gmail.com>]

23.02.2022 00:43, Mark Brown пишет:
> The smb347 has a very sparse register map (the maximum register is 0x3f but
> less than 10% of the possible registers appear to be defined) and doesn't
> have any hardware defaults specified so the sparser data structure of an
> rbtree is a better fit for it's needs than a flat cache. Since it uses I2C
> for the control interface there is no performance concern with the slightly
> more involved code so let's convert it.
> 
> This will mean we avoid any issues created by assuming that any previously
> unaccessed registers hold a value that doesn't match what's in the hardware
> (eg, an _update_bits() suppressing a write).
> 
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>  drivers/power/supply/smb347-charger.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/power/supply/smb347-charger.c b/drivers/power/supply/smb347-charger.c
> index d56e469043bb..1511f71f937c 100644
> --- a/drivers/power/supply/smb347-charger.c
> +++ b/drivers/power/supply/smb347-charger.c
> @@ -1488,8 +1488,7 @@ static const struct regmap_config smb347_regmap = {
>  	.max_register	= SMB347_MAX_REGISTER,
>  	.volatile_reg	= smb347_volatile_reg,
>  	.readable_reg	= smb347_readable_reg,
> -	.cache_type	= REGCACHE_FLAT,
> -	.num_reg_defaults_raw = SMB347_MAX_REGISTER,
> +	.cache_type	= REGCACHE_RBTREE,

Why you removed the num_reg_defaults_raw? It was needed in order to
populate the default values on the regcache init, is it somehow
different for the REGCACHE_RBTREE? Otherwise this patch is incorrect.