linux-kernel - Re: [PATCH 1/4] drm/bridge: ti-sn65dsi86: Combine register accesses in ti_sn_aux

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Message-ID: <CAD=FV=UUdYR-R9r9BoHWSoQEejL3P0r+bG1m787tVkNQHhZDuw@mail.gmail.com>
Date:   Thu, 29 Oct 2020 09:10:29 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     Andrzej Hajda <a.hajda@...sung.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        LKML <linux-kernel@...r.kernel.org>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Sean Paul <seanpaul@...omium.org>,
        Sam Ravnborg <sam@...nborg.org>
Subject: Re: [PATCH 1/4] drm/bridge: ti-sn65dsi86: Combine register accesses
 in ti_sn_aux_transfer()

Hi,

On Wed, Oct 28, 2020 at 6:11 PM Stephen Boyd <swboyd@...omium.org> wrote:
>
> These register reads and writes are sometimes directly next to each
> other in the register address space. Let's use regmap bulk read/write
> APIs to get the data with one transfer instead of multiple i2c
> transfers. This helps cut down on the number of transfers in the case of
> something like reading an EDID where we read in blocks of 16 bytes at a
> time and the last for loop here is sending an i2c transfer for each of
> those 16 bytes, one at a time. Ouch!
>
> Cc: Douglas Anderson <dianders@...omium.org>
> Cc: Laurent Pinchart <Laurent.pinchart@...asonboard.com>
> Cc: Jonas Karlman <jonas@...boo.se>
> Cc: Jernej Skrabec <jernej.skrabec@...l.net>
> Cc: Sean Paul <seanpaul@...omium.org>

+Sam Ravnborg has helped land a few changes to this bridge drive in
the past, so maybe good to CC him if you have future spins?

> Signed-off-by: Stephen Boyd <swboyd@...omium.org>
> ---
>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 50 ++++++++++++---------------
>  1 file changed, 22 insertions(+), 28 deletions(-)

Since we already did some early reviews off-list, it's not a surprise
that I have no comments.  ;-)

Reviewed-by: Douglas Anderson <dianders@...omium.org>