Re: [PATCH v7 0/7] i2c-atr and FPDLink
From: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Date: 2023-01-20 16:21:24
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linux-i2c, linux-media, lkml
On 20/01/2023 18:17, Luca Ceresoli wrote:
Hi Andy, On Fri, 20 Jan 2023 18:00:02 +0200 Andy Shevchenko [off-list ref] wrote:quoted
On Thu, Jan 19, 2023 at 09:43:58AM +0100, Luca Ceresoli wrote:quoted
On Wed, 18 Jan 2023 19:43:23 +0200 Andy Shevchenko [off-list ref] wrote:quoted
On Wed, Jan 18, 2023 at 07:28:20PM +0200, Tomi Valkeinen wrote:quoted
On 18/01/2023 18:01, Andy Shevchenko wrote:quoted
On Wed, Jan 18, 2023 at 02:40:24PM +0200, Tomi Valkeinen wrote:...quoted
quoted
quoted
Can you clarify what you mean here? The i2c_clients are not aware of the i2c-atr. They are normal i2c clients. The FPD-Link drivers are aware of the ATR, as the FPD-Link hardware contains the ATR support.Can't that hardware be represented as I2C adapter? In such case the ATR specifics can be hidden from the client (drivers). I'm worrying about code duplication and other things that leak into drivers as ATR callbacks.Which callbacks do you refer to? i2c_atr_ops? I don't think we can do without the attach/detach_client ones, it's where the driver-specific implementation is hooked for the generic ATR infra to call it. However now I noticed the select/deselect ops are still there. IIRC they are not used by any driver and in the past the plan was to just remove them. Tomi, do you think there is a good reason to keep them?quoted
It might be that I didn't get how hw exactly functioning on this level and why we need those callbacks.As far as "how hw exactly works", in case you haven't seen that, the best explanation I was able to give is in my ELCE 2019 talk, at minute ~22. It's a 2-3 minute watch. The slides have pointers to other talks and discussion.Probably I have missed the URL in the discussion, care to resend?I hadn't sent any URL :) Here's the shortcut to go straight to the ATR description: https://youtu.be/7hLv6fYAW-E?t=1350 Slides: https://elinux.org/images/f/fc/Ceresoli-elce2019-video-serdes-linux.pdf
A small note: the current implementation doesn't match the slides, as the adapter is now (at least kind of) in the serializer (the "ideal solution" in the slides. Tomi