From: Frank Zago <frank@zago.net>
To: Johan Hovold <johan@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-kernel@vger.kernel.org,
Jan-Niklas Burfeind <kernel@aiyionpri.me>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>,
Wolfram Sang <wsa@kernel.org>,
linux-usb@vger.kernel.org, gunar@schorcht.net
Subject: Re: [PATCH v2 1/2] Revert "USB: serial: ch341: add new Product ID for CH341A"
Date: Tue, 11 May 2021 20:07:31 -0500 [thread overview]
Message-ID: <8b3c348f-9e05-29f9-9197-8ddf1c8a9e8b@zago.net> (raw)
In-Reply-To: <YJjjfx49nCflzFbR@hovoldconsulting.com>
Hello,
On 5/10/21 2:40 AM, Johan Hovold wrote:
> On Thu, Apr 22, 2021 at 07:28:51PM -0500, Frank Zago wrote:
>> From: frank zago <frank@zago.net>
>>
>> The 0x5512 USB PID is for the I2C/GPIO/SPI interfaces. UART is
>> still present but only the TX and RX pins are available; DTS, DTR,
>> ... are used for other things. Remove the PID, and let a I2C
>> driver bind to it.
>>
>> Existing CH341 boards usually have physical jumpers to switch
>> between the 3 modes.
>>
>> This reverts commit 46ee4abb10a07bd8f8ce910ee6b4ae6a947d7f63.
>
> You can't just revert something which people clearly depend on and
> therefore added to the kernel in the first place.
That device in UART mode was already supported by the serial driver. The
original submitter just had to move a jumper on his board. There was no
need to patch the kernel.
That product ID also supports UART but in a limited way, as only the RX and TX
pins are available. However it is the only one that supports i2c/spi/gpio, and
that's why I have to revert the patch.
If that's desired, the new driver could add support for that as well, but I don't
think it's worth the effort.
>
> Can you reprogram the device with a newly allocated PID to be used
> for i2c-only instead?
It is possible if the device has an SPI flash connected to it, but none of
the cheap boards have that.
Frank.
next prev parent reply other threads:[~2021-05-12 1:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-23 0:28 [PATCH v2 1/2] Revert "USB: serial: ch341: add new Product ID for CH341A" Frank Zago
2021-04-23 0:28 ` [PATCH v2 2/2] USB: misc: Add driver for the WCH CH341 in I2C/GPIO mode Frank Zago
2021-05-10 7:53 ` Johan Hovold
2021-05-10 7:40 ` [PATCH v2 1/2] Revert "USB: serial: ch341: add new Product ID for CH341A" Johan Hovold
2021-05-12 1:07 ` Frank Zago [this message]
2021-05-12 9:55 ` Johan Hovold
2021-05-13 1:00 ` Frank Zago
2021-05-13 11:31 ` Johan Hovold
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