From: "H. Nikolaus Schaller" <hns@goldelico.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Sven Van Asbroeck <thesven73@gmail.com>,
Lukas Wunner <lukas@wunner.de>, Mark Brown <broonie@kernel.org>,
kernel list <linux-kernel@vger.kernel.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Discussions about the Letux Kernel
<letux-kernel@openphoenux.org>,
Andreas Kemnade <andreas@kemnade.info>
Subject: Re: [BUG] SPI broken for SPI based panel drivers
Date: Wed, 9 Dec 2020 09:45:04 +0100 [thread overview]
Message-ID: <D1D5D5B7-72AB-42F7-A460-9B61932C869B@goldelico.com> (raw)
In-Reply-To: <CACRpkdYbGBT1gYZ06W7G-tjx9J4YG1bi1g2GOAUAH0tzH8YbNw@mail.gmail.com>
Hi Linus,
> Am 09.12.2020 um 09:38 schrieb Linus Walleij <linus.walleij@linaro.org>:
>
> On Sat, Dec 5, 2020 at 8:07 AM H. Nikolaus Schaller <hns@goldelico.com> wrote:
>
>> I find it interesting that so far nobody wants to take responsibility
>> for a decision
> (...)
>
>
>>> What I can do is to provide just a skeleton for the table that you or Linus
>>> can fix/fill in and make a patch out of it. Is attached and the ??? is
>>> something you should discuss and define.
>>
>> Please take the attached diff, comment it here and define the question marks
>> according to your intention and then make a patch for the YAML bindings out
>> of it. (I can't do because I don't know your intentions and what to write into
>> the commit message).
>
> I'll comment what I know, then you can send a proper patch to
> Mark. But you really need more people than me to look at this.
>
>> + device node | cs-gpio | CS pin state active | Note
>> + ================+===============+=====================+=====
>> + spi-cs-high | - | H |
>> + - | - | L |
>> + spi-cs-high | ACTIVE_HIGH | H |
>> + - | ACTIVE_HIGH | L (or H ???) | 1
>
> When using GPIO descriptors it will be enforced to ACTIVE_LOW (L) with an
> explicit warning in dmesg, see drivers/gpio/gpiolib-of.c
Ok, so in this line the L is ok.
>
> When using legacy GPIOs, will be enforced ACTIVE_LOW by the SPI
> core.
>
>> + spi-cs-high | ACTIVE_LOW | H (or L ???) | 2
>
> When using GPIO descriptors it will be enforced to ACTIVE_HIGH (H) with an
> explicit warning in dmesg, see drivers/gpio/gpiolib-of.c
Ok, so my assumption about H is right and not the part in parenthesis with ???.
>
>> + 3) Effectively this rule defines that the ACTIVE level of the
>> + gpio has to be ignored
>
> Nr 3 isn't tagged in the table.
Well, it was thought as a third but general note. Maybe should have been a *)
or omitted since the table stands for itself.
>
> Yours,
> Linus Walleij
So let me prepare a patch with fixes for this.
BR and thanks,
Nikolaus
next prev parent reply other threads:[~2020-12-09 8:48 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 19:03 [BUG] SPI broken for SPI based panel drivers H. Nikolaus Schaller
2020-11-30 20:13 ` Sven Van Asbroeck
2020-11-30 20:22 ` Sven Van Asbroeck
2020-12-01 8:59 ` H. Nikolaus Schaller
2020-12-01 12:16 ` Mark Brown
2020-12-01 14:05 ` H. Nikolaus Schaller
2020-12-01 14:20 ` Linus Walleij
2020-12-01 14:34 ` Sven Van Asbroeck
2020-12-01 14:35 ` H. Nikolaus Schaller
2020-12-01 15:52 ` Sven Van Asbroeck
2020-12-01 16:46 ` H. Nikolaus Schaller
2020-12-01 16:10 ` Sven Van Asbroeck
2020-12-01 16:39 ` H. Nikolaus Schaller
2020-12-01 16:53 ` Sven Van Asbroeck
2020-12-01 17:10 ` H. Nikolaus Schaller
2020-12-01 18:43 ` Sven Van Asbroeck
2020-12-02 12:19 ` Mark Brown
2020-12-04 10:08 ` H. Nikolaus Schaller
2020-12-04 13:46 ` Sven Van Asbroeck
2020-12-04 16:49 ` H. Nikolaus Schaller
2020-12-04 19:19 ` Sven Van Asbroeck
2020-12-04 21:31 ` H. Nikolaus Schaller
2020-12-05 0:25 ` Linus Walleij
2020-12-05 7:04 ` H. Nikolaus Schaller
2020-12-09 8:04 ` Andreas Kemnade
2020-12-09 8:40 ` H. Nikolaus Schaller
2020-12-09 8:38 ` Linus Walleij
2020-12-09 8:45 ` H. Nikolaus Schaller [this message]
2020-12-01 22:51 ` Linus Walleij
2020-12-01 16:44 ` [Letux-kernel] " Andreas Kemnade
2020-12-01 16:51 ` H. Nikolaus Schaller
2020-12-01 16:52 ` H. Nikolaus Schaller
2020-12-01 16:55 ` Sven Van Asbroeck
2020-12-01 16:20 ` Mark Brown
2020-12-01 16:41 ` H. Nikolaus Schaller
2020-12-01 17:11 ` Mark Brown
2020-12-01 12:41 ` Sven Van Asbroeck
2020-12-01 13:32 ` H. Nikolaus Schaller
2020-12-01 14:08 ` Sven Van Asbroeck
2020-12-01 15:33 ` Mark Brown
2020-12-05 20:57 ` Pavel Machek
2020-12-07 13:43 ` Mark Brown
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