From: Michael Walle <michael@walle.cc>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>,
Hans de Goede <hdegoede@redhat.com>,
Sander Vanheule <sander@svanheule.net>,
Andrew Lunn <andrew@lunn.ch>, Pavel Machek <pavel@ucw.cz>,
Rob Herring <robh+dt@kernel.org>,
Lee Jones <lee.jones@linaro.org>, Mark Brown <broonie@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Linux LED Subsystem <linux-leds@vger.kernel.org>,
devicetree <devicetree@vger.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 0/6] RTL8231 GPIO expander support
Date: Tue, 01 Jun 2021 13:41:57 +0200 [thread overview]
Message-ID: <401805ef27bb273d7aca4f3377b53b07@walle.cc> (raw)
In-Reply-To: <CACRpkdb4j6krXwdZGtth9b2W2bAdy9_StGbse_YbBY86-AWdLg@mail.gmail.com>
Am 2021-06-01 12:51, schrieb Linus Walleij:
> On Tue, Jun 1, 2021 at 12:18 PM Michael Walle <michael@walle.cc> wrote:
>> Am 2021-06-01 11:59, schrieb Linus Walleij:
>
>> > Just regarding all registers/memory cells in a register page
>> > as default volatile (which is what we do a lot of the time)
>> > has its upsides: bugs like this doesn't happen.
>>
>> I don't think this is the bug here. If it is really a write-only
>> register
>> the problem is the read in RMW. Because reading the register will
>> return
>> the input value instead of the (previously written) output value.
>
> True that. Write and read semantics differ on the register.
>
> Volatile is used for this and some other things,
> like for example interrupts being cleared when a register
> is read so it is strictly read-once.
Isn't that what precious is for?
> So the regmap config is really important to get right.
>
> IIUC one of the ambitions around Rust is to encode this
> in how memory is specified in the language. (I am still
> thinking about whether that is really a good idea or not.)
--
-michael
next prev parent reply other threads:[~2021-06-01 11:42 UTC|newest]
Thread overview: 114+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 12:25 [PATCH 0/5] RTL8231 GPIO expander support Sander Vanheule
2021-05-11 12:25 ` [PATCH 1/5] dt-bindings: leds: Binding for RTL8231 scan matrix Sander Vanheule
2021-05-17 22:31 ` Rob Herring
2021-05-19 16:39 ` Sander Vanheule
2021-05-11 12:25 ` [PATCH 2/5] dt-bindings: mfd: Binding for RTL8231 Sander Vanheule
2021-05-17 22:38 ` Rob Herring
2021-05-19 16:53 ` Sander Vanheule
2021-05-11 12:25 ` [PATCH 3/5] mfd: Add RTL8231 core device Sander Vanheule
2021-05-12 12:29 ` kernel test robot
2021-05-12 13:13 ` kernel test robot
2021-05-19 14:58 ` Lee Jones
2021-05-19 15:11 ` Sander Vanheule
2021-05-11 12:25 ` [PATCH 4/5] pinctrl: Add RTL8231 pin control and GPIO support Sander Vanheule
2021-05-11 12:25 ` [PATCH 5/5] leds: Add support for RTL8231 LED scan matrix Sander Vanheule
[not found] ` <CAHp75VffoKyyPJbdtKMLx575c9LT0S8+EHOk7Mw36j=aTL6Q4Q@mail.gmail.com>
2021-05-16 21:40 ` [PATCH 0/5] RTL8231 GPIO expander support Sander Vanheule
2021-05-17 8:13 ` Andy Shevchenko
2021-05-17 8:50 ` Sander Vanheule
2021-05-17 19:32 ` Sander Vanheule
2021-05-17 19:28 ` [PATCH v2 0/7] " Sander Vanheule
2021-05-17 19:28 ` [PATCH v2 1/7] regmap: Add MDIO bus support Sander Vanheule
2021-05-19 16:12 ` Mark Brown
2021-05-17 19:28 ` [PATCH v2 2/7] gpio: regmap: Add configurable dir/value order Sander Vanheule
2021-05-17 21:06 ` Andy Shevchenko
2021-05-18 1:40 ` Andrew Lunn
2021-05-18 11:39 ` Sander Vanheule
2021-05-23 22:21 ` Sander Vanheule
2021-05-18 8:39 ` Michael Walle
2021-05-18 10:39 ` Andy Shevchenko
2021-05-23 21:19 ` Sander Vanheule
2021-05-17 19:28 ` [PATCH v2 3/7] dt-bindings: leds: Binding for RTL8231 scan matrix Sander Vanheule
2021-05-17 19:28 ` [PATCH v2 4/7] dt-bindings: mfd: Binding for RTL8231 Sander Vanheule
2021-05-18 22:02 ` Linus Walleij
2021-05-17 19:28 ` [PATCH v2 5/7] mfd: Add RTL8231 core device Sander Vanheule
2021-05-17 21:18 ` Andy Shevchenko
2021-05-23 21:28 ` Sander Vanheule
2021-05-24 7:49 ` Andy Shevchenko
2021-05-24 7:50 ` Sander Vanheule
2021-05-24 7:55 ` Andy Shevchenko
2021-05-24 8:04 ` Sander Vanheule
2021-05-17 19:28 ` [PATCH v2 6/7] pinctrl: Add RTL8231 pin control and GPIO support Sander Vanheule
2021-05-17 21:42 ` Andy Shevchenko
2021-05-17 21:46 ` Andy Shevchenko
2021-05-23 21:42 ` Sander Vanheule
2021-05-17 19:28 ` [PATCH v2 7/7] leds: Add support for RTL8231 LED scan matrix Sander Vanheule
2021-05-17 22:00 ` Andy Shevchenko
2021-05-23 21:53 ` Sander Vanheule
2021-05-19 16:10 ` (subset) [PATCH v2 0/7] RTL8231 GPIO expander support Mark Brown
2021-05-23 22:33 ` [PATCH v3 0/6] " Sander Vanheule
2021-05-23 22:33 ` [PATCH v3 1/6] gpio: regmap: Add quirk for output data register Sander Vanheule
2021-05-28 6:40 ` Michael Walle
2021-06-03 10:03 ` Sander Vanheule
2021-05-31 7:25 ` Bartosz Golaszewski
2021-05-23 22:34 ` [PATCH v3 2/6] dt-bindings: leds: Binding for RTL8231 scan matrix Sander Vanheule
2021-06-02 18:58 ` Rob Herring
2021-05-23 22:34 ` [PATCH v3 3/6] dt-bindings: mfd: Binding for RTL8231 Sander Vanheule
2021-05-27 23:31 ` Linus Walleij
2021-06-02 19:02 ` Rob Herring
2021-05-23 22:34 ` [PATCH v3 4/6] mfd: Add RTL8231 core device Sander Vanheule
2021-05-24 8:02 ` Andy Shevchenko
2021-05-24 8:23 ` Sander Vanheule
2021-05-24 10:18 ` Andy Shevchenko
2021-05-24 11:41 ` Sander Vanheule
2021-05-23 22:34 ` [PATCH v3 5/6] pinctrl: Add RTL8231 pin control and GPIO support Sander Vanheule
2021-05-28 6:29 ` Michael Walle
2021-05-28 6:42 ` Sander Vanheule
2021-05-28 6:43 ` Michael Walle
2021-05-23 22:34 ` [PATCH v3 6/6] leds: Add support for RTL8231 LED scan matrix Sander Vanheule
2021-05-24 10:24 ` Andy Shevchenko
2021-05-24 12:04 ` Sander Vanheule
2021-05-24 12:47 ` Andy Shevchenko
2021-05-24 15:30 ` Sander Vanheule
2021-05-24 1:10 ` [PATCH v3 0/6] RTL8231 GPIO expander support Andrew Lunn
2021-05-24 7:53 ` Andy Shevchenko
2021-05-24 11:41 ` Sander Vanheule
2021-05-24 12:54 ` Andy Shevchenko
2021-05-24 15:03 ` Sander Vanheule
2021-05-24 16:30 ` Andy Shevchenko
2021-05-25 17:11 ` Andy Shevchenko
2021-05-25 18:00 ` Sander Vanheule
2021-05-26 21:02 ` Sander Vanheule
2021-05-27 10:38 ` Andy Shevchenko
2021-05-27 10:41 ` Hans de Goede
2021-05-24 15:20 ` Sander Vanheule
2021-05-28 6:37 ` Michael Walle
2021-05-30 16:19 ` Sander Vanheule
2021-05-30 16:51 ` Hans de Goede
2021-05-30 18:16 ` Andy Shevchenko
2021-05-30 21:22 ` Michael Walle
2021-05-31 8:36 ` Sander Vanheule
2021-05-31 10:02 ` Michael Walle
[not found] ` <CAHp75VfOrUBRQH1vrXEwHN4ZPojQfQju-_wp_3djZeozEaatug@mail.gmail.com>
2021-05-31 15:33 ` [PATCH 0/5] " Sander Vanheule
2021-05-31 15:48 ` Andy Shevchenko
2021-06-01 11:49 ` Michael Walle
2021-06-01 15:24 ` Andy Shevchenko
2021-06-02 20:20 ` Sander Vanheule
2021-06-01 9:59 ` [PATCH v3 0/6] " Linus Walleij
2021-06-01 10:18 ` Michael Walle
2021-06-01 10:51 ` Linus Walleij
2021-06-01 11:41 ` Michael Walle [this message]
2021-06-01 11:48 ` Linus Walleij
2021-06-03 10:00 ` [PATCH v4 0/5] " Sander Vanheule
2021-06-03 10:00 ` [PATCH v4 1/5] dt-bindings: leds: Binding for RTL8231 scan matrix Sander Vanheule
2021-06-03 10:00 ` [PATCH v4 2/5] dt-bindings: mfd: Binding for RTL8231 Sander Vanheule
2021-06-03 10:00 ` [PATCH v4 3/5] mfd: Add RTL8231 core device Sander Vanheule
2021-06-03 10:58 ` Andy Shevchenko
2021-06-03 11:28 ` Sander Vanheule
2021-06-03 14:03 ` Andrew Lunn
2021-06-03 15:20 ` Sander Vanheule
2021-06-05 11:07 ` Sander Vanheule
2021-06-03 10:00 ` [PATCH v4 4/5] pinctrl: Add RTL8231 pin control and GPIO support Sander Vanheule
2021-06-03 10:18 ` Andy Shevchenko
2021-06-04 22:10 ` Linus Walleij
2021-06-03 10:00 ` [PATCH v4 5/5] leds: Add support for RTL8231 LED scan matrix Sander Vanheule
2021-06-03 11:01 ` Andy Shevchenko
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