From: Michael Walle <michael@walle.cc>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Sungbo Eo <mans0n@gorani.run>,
Linus Walleij <linus.walleij@linaro.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>
Subject: Re: [PATCH] gpio: add GPO driver for PCA9570
Date: Sat, 27 Jun 2020 18:58:54 +0200 [thread overview]
Message-ID: <83f1fba7fb04780b84c5e96a184f61f9@walle.cc> (raw)
In-Reply-To: <CAHp75VciJmV1wTB0AWvbjyOZzzk1A1KC70+dtr0jNziAvQ2tHw@mail.gmail.com>
Hi,
Am 2020-06-24 16:52, schrieb Andy Shevchenko:
> On Wed, Jun 24, 2020 at 4:46 PM Michael Walle <michael@walle.cc> wrote:
[..]
>> So you just write one byte of data (or you might repeat it, but
>> that is just as if you start a new i2c transaction, just that
>> you save the i2c addressing).
>
> You can write the same value twice.
> It means that the first byte can represent the register address. But
> it's still too volatile.
In this case the output pin will hold the value of the "fake" address
register for a short period of time. No?
> Perhaps regmap can gain something like register-less communication.
I don't know if that is worth it (and if that is an intended use of
regmap).
-michael
next prev parent reply other threads:[~2020-06-27 16:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 6:05 [PATCH] gpio: add GPO driver for PCA9570 Sungbo Eo
2020-06-23 8:31 ` Michael Walle
2020-06-23 12:22 ` Sungbo Eo
2020-06-23 12:47 ` Michael Walle
2020-06-24 13:33 ` Andy Shevchenko
2020-06-24 13:46 ` Michael Walle
2020-06-24 14:52 ` Andy Shevchenko
2020-06-27 16:58 ` Michael Walle [this message]
2020-06-24 12:29 ` Bartosz Golaszewski
2020-06-24 13:01 ` Andy Shevchenko
2020-06-25 7:34 ` Sungbo Eo
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