Re: [PATCH v3 5/5] Input: exc3000 - add firmware update support

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Lucas,

On Mon, Jan 25, 2021 at 07:25:27PM +0100, Lucas Stach wrote:
> This change allows the device firmware to be updated by putting a firmware
> file in /lib/firmware and providing the name of the file via the update_fw
> sysfs property. The driver will then flash the firmware image into the
> controller internal storage and restart the controller to activate the new
> firmware.
> 
> The implementation was done by looking at the the messages passed between
> the controller and proprietary vendor update tool. Not every detail of the
> protocol is totally well understood, so the implementation still has some
> "monkey see, monkey do" parts, as far as they have been found to be required
> for the update to succeed.
> 
> Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
> ---
>  .../ABI/testing/sysfs-driver-input-exc3000    |  20 ++
>  drivers/input/touchscreen/exc3000.c           | 240 +++++++++++++++++-
>  2 files changed, 258 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/sysfs-driver-input-exc3000 b/Documentation/ABI/testing/sysfs-driver-input-exc3000
> index 704434b277b0..123a00ccee8b 100644
> --- a/Documentation/ABI/testing/sysfs-driver-input-exc3000
> +++ b/Documentation/ABI/testing/sysfs-driver-input-exc3000
> @@ -24,3 +24,23 @@ Description:	Reports the type identification provided by the touchscreen, for ex
>  		Access: Read
>  
>  		Valid values: Represented as string
> +
> +What:		/sys/bus/i2c/devices/xxx/update_fw
> +Date:		Jan 2021
> +Contact:	linux-input@vger.kernel.org
> +Description:	Allows to specify a firlename of a firmware file located in /lib/firmware/ that will be
> +		used to update the application firmware on the touchscreen controller. For example
> +		"eeti/eeti_27_0_EDipper_0735.fw"

I believe the current idiomatic way is to have statically defined
firmware name (it can still encode vid/pid/model info etc) and do not
re-implement variable firmware name in every driver.

I think if this really is required we need to add this feature of
overriding default firmware name to firmware loader maybe?

Thanks.

-- 
Dmitry