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From: Greg KH <gregkh@linuxfoundation.org>
To: Frank Zago <frank@zago.net>
Cc: linux-serial@vger.kernel.org
Subject: Re: [PATCH 1/1] [RFC] USB: serial: ch341: Add I2C support to CH341 driver
Date: Tue, 23 Mar 2021 10:32:03 +0100	[thread overview]
Message-ID: <YFm1kzrPJ00HhoHR@kroah.com> (raw)
In-Reply-To: <4286affb-bed1-0fc1-1d07-a5cb8d475fb1@zago.net>

On Mon, Mar 22, 2021 at 10:22:54PM -0500, Frank Zago wrote:
> The Winchiphead CH341 IC is more than a UART interface. Amongst other
> things, it can talk to an I2C bus.
> 
> Several people have contributed to an out of tree driver: Tse Lun
> Bien, Marco Gittler and Till Harbaum.
> 
>   https://github.com/allanbian1017/i2c-ch341-usb.git
> 
> This commit integrates the I2C portions into the CH341 serial driver
> and exposes the I2C device.
> 
> Tested with a CH341A, CH341B and CH341T.
> 
> Signed-off-by: Frank Zago <frank@zago.net>
> ---
> 
> I didn't find a way to say a USB device has several functions. I
> followed what the CP210x driver did with gpio, but I think it's a
> hack. The private data for the I2C part should be linked to the USB
> device, not the serial port. It works here and in the cp210x driver
> because there is only 1 serial port in the device. If it had 2 or more
> ports, I believe bad things would happen. So is there a better way to
> handle USB devices like that?
> 
> For info, the CH341A/B supports 3 different modes, each with a different
> USB PID, usually selected by jumpers. All of them support I2C, but
> only 2 support UART, one supports SPI and 2 support GPIOs.
> 
> 
>  drivers/usb/serial/Kconfig |   4 +-
>  drivers/usb/serial/ch341.c | 284 ++++++++++++++++++++++++++++++++++++-
>  2 files changed, 283 insertions(+), 5 deletions(-)

$ ./scripts/get_maintainer.pl --file drivers/usb/serial/ch341.c
Johan Hovold <johan@kernel.org> (maintainer:USB SERIAL SUBSYSTEM)
Greg Kroah-Hartman <gregkh@linuxfoundation.org> (supporter:USB SUBSYSTEM)
linux-usb@vger.kernel.org (open list:USB SERIAL SUBSYSTEM)
linux-kernel@vger.kernel.org (open list)

Please always send patches to the proper people and mailing lists,
otherwise it will be lost :(

thanks,

greg k-h

      reply	other threads:[~2021-03-23  9:32 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-23  3:22 [PATCH 1/1] [RFC] USB: serial: ch341: Add I2C support to CH341 driver Frank Zago
2021-03-23  9:32 ` Greg KH [this message]

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