From: Dmitry Osipenko <dmitry.osipenko@collabora.com>
To: Akhil R <akhilrajeev@nvidia.com>,
Dmitry Osipenko <digetx@gmail.com>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"christian.koenig@amd.com" <christian.koenig@amd.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Laxman Dewangan <ldewangan@nvidia.com>,
"linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
"sumit.semwal@linaro.org" <sumit.semwal@linaro.org>,
"thierry.reding@gmail.com" <thierry.reding@gmail.com>,
"wsa@kernel.org" <wsa@kernel.org>
Subject: Re: [PATCH RESEND 1/2] i2c: tegra: Add GPCDMA support
Date: Mon, 22 Aug 2022 12:45:38 +0300 [thread overview]
Message-ID: <ebb0764f-db92-d69d-49ac-151f4e3e0b8a@collabora.com> (raw)
In-Reply-To: <SJ1PR12MB6339FC1F82EB1BB7417E533BC0719@SJ1PR12MB6339.namprd12.prod.outlook.com>
On 8/22/22 09:56, Akhil R wrote:
>> 19.08.2022 18:15, Dmitry Osipenko пишет:
>>> 19.08.2022 15:23, Akhil R пишет:
>>>> if (of_device_is_compatible(np, "nvidia,tegra210-i2c-vi"))
>>>> i2c_dev->is_vi = true;
>>>> + else
>>>> + i2c_dev->dma_support = !!(of_find_property(np, "dmas",
>>>> + NULL));
>>>
>>> 1. You leak the np returned by of_find_property().
>>>
>>> 2. There is device_property_read_bool() for this kind of
>>> property-exists checks.
> Okay. I went by the implementation in of_dma_request_slave_channel() to
> check 'dmas'.
>
>>>
>>> 3. If "dmas" is missing in DT, then dma_request_chan() should return
>>> NULL and everything will work fine. I suppose you haven't tried to
>>> test this code.
>>
>> Although, no. It should return ERR_PTR(-ENODEV) and then you should check
>> the return code.
> Yes. Agree that it is more agnostic to check for ERR_PTR(-ENODEV). But since I
> call tegra_init_dma() for every large transfer until DMA is initialized, wouldn't
> it be better to have a flag inside the driver so that we do not have to go through
> so many functions for every attempted DMA transaction to find out that the DT
> properties don't exist?
>
> Shall I just put i2c_dev->dma_support = true here since DMA is supported by
> hardware? It would turn false if dma_request_chan() returns something other
> than -EPROBE_DEFER.
>
> if (of_device_is_compatible(np, "nvidia,tegra210-i2c-vi"))
> i2c_dev->is_vi = true;
> + else
> + i2c_dev->dma_support = true;
The code already has dma_mode for that. I don't see why another variable
is needed.
Either add new generic dma_request_chan_optional() that will return NULL
if channel is not available and make Tegra I2C driver to use it, or
handle the error code returned by dma_request_chan().
--
Best regards,
Dmitry
next prev parent reply other threads:[~2022-08-22 9:45 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-19 12:23 [PATCH RESEND 0/2] Add GPCDMA support to Tegra234 I2C Akhil R
2022-08-19 12:23 ` [PATCH RESEND 1/2] i2c: tegra: Add GPCDMA support Akhil R
2022-08-19 15:15 ` Dmitry Osipenko
2022-08-19 15:27 ` Dmitry Osipenko
2022-08-22 6:56 ` Akhil R
2022-08-22 9:45 ` Dmitry Osipenko [this message]
2022-08-22 10:29 ` Akhil R
2022-08-22 20:33 ` Dmitry Osipenko
2022-08-22 21:08 ` Dmitry Osipenko
2022-08-23 5:17 ` Akhil R
2022-08-23 8:39 ` Dmitry Osipenko
2022-08-23 8:45 ` Dmitry Osipenko
2022-08-23 12:55 ` Akhil R
2022-08-23 13:32 ` Dmitry Osipenko
2022-08-25 16:41 ` Akhil R
2022-09-01 14:40 ` Thierry Reding
2022-09-02 11:25 ` Dmitry Osipenko
2022-08-19 12:23 ` [PATCH RESEND 2/2] arm64: tegra: Add GPCDMA support for Tegra234 I2C Akhil R
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ebb0764f-db92-d69d-49ac-151f4e3e0b8a@collabora.com \
--to=dmitry.osipenko@collabora.com \
--cc=akhilrajeev@nvidia.com \
--cc=christian.koenig@amd.com \
--cc=devicetree@vger.kernel.org \
--cc=digetx@gmail.com \
--cc=jonathanh@nvidia.com \
--cc=ldewangan@nvidia.com \
--cc=linux-i2c@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=robh+dt@kernel.org \
--cc=sumit.semwal@linaro.org \
--cc=thierry.reding@gmail.com \
--cc=wsa@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).