linux-kernel - Re: [PATCH v5 1/8] regmap: Support atomic forced uncached reads

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Date:   Sun, 13 Jun 2021 00:23:54 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Sander Vanheule <sander@...nheule.net>
Cc:     Pavel Machek <pavel@....cz>, Rob Herring <robh+dt@...nel.org>,
        Lee Jones <lee.jones@...aro.org>,
        Mark Brown <broonie@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Michael Walle <michael@...le.cc>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Linux LED Subsystem <linux-leds@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Andrew Lunn <andrew@...n.ch>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 1/8] regmap: Support atomic forced uncached reads

On Sun, Jun 13, 2021 at 12:13 AM Sander Vanheule <sander@...nheule.net> wrote:
>
> When a user wants to read a single uncached register, cache bypassing
> can be enabled. However, this is not atomic unless an external lock is
> used for the regmap. When using regcache_cache_bypass, the original
> bypass state also cannot be restored.
>
> Add support to atomically read a single uncached value, bypassing any
> regmap cache.

> +int regmap_read_bypassed(struct regmap *map, unsigned int reg, unsigned int *val)

If this is acceptable in general, I will rather name the function like
regmap_nocache_read() to be aligned with the other API naming pattern
(see below).

>  int regmap_raw_write_async(struct regmap *map, unsigned int reg,
>                            const void *val, size_t val_len);
>  int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);
> +int regmap_read_bypassed(struct regmap *map, unsigned int reg, unsigned int *val);
>  int regmap_raw_read(struct regmap *map, unsigned int reg,
>                     void *val, size_t val_len);
>  int regmap_noinc_read(struct regmap *map, unsigned int reg,


-- 
With Best Regards,
Andy Shevchenko