From: Sean Paul <sean@poorly.run>
To: Douglas Anderson <dianders@chromium.org>
Cc: Sean Paul <seanpaul@chromium.org>,
Thierry Reding <thierry.reding@gmail.com>,
Sandeep Panda <spanda@codeaurora.org>,
linux-arm-msm@vger.kernel.org,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
jsanka@codeaurora.org, ryandcase@chromium.org,
David Airlie <airlied@linux.ie>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/6] drm/panel: simple: Support panels with HPD where HPD isn't connected
Date: Fri, 26 Oct 2018 10:41:11 -0400 [thread overview]
Message-ID: <20181026144111.GQ154160@art_vandelay> (raw)
In-Reply-To: <20181025222134.174583-2-dianders@chromium.org>
On Thu, Oct 25, 2018 at 03:21:30PM -0700, Douglas Anderson wrote:
> Some eDP panels that are designed to be always connected to a board
> use their HPD signal to signal that they've finished powering on and
> they're ready to be talked to.
>
> However, for various reasons it's possible that the HPD signal from
> the panel isn't actually hooked up. In the case where the HPD isn't
> hooked up you can look at the timing diagram on the panel datasheet
> and insert a delay for the maximum amount of time that the HPD might
> take to come up.
>
> Let's add support in simple-panel for this concept.
>
> At the moment we will co-opt the existing "prepare" delay to keep
> track of the delay and we'll use a boolean to specify that a given
> panel should only apply the delay if the "no-hpd" property was
> specified.
>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>
> ---
>
> Changes in v2:
> - Use "hpd_absent_delay" property instead of a bool + prepare delay
>
> drivers/gpu/drm/panel/panel-simple.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> index 97964f7f2ace..687fd087b9fc 100644
> --- a/drivers/gpu/drm/panel/panel-simple.c
> +++ b/drivers/gpu/drm/panel/panel-simple.c
> @@ -56,6 +56,8 @@ struct panel_desc {
> /**
> * @prepare: the time (in milliseconds) that it takes for the panel to
> * become ready and start receiving video data
> + * @hpd_absent_delay: Add this to the prepare delay if we know Hot
> + * Plug Detect isn't used.
> * @enable: the time (in milliseconds) that it takes for the panel to
> * display the first valid frame after starting to receive
> * video data
> @@ -66,6 +68,7 @@ struct panel_desc {
> */
> struct {
> unsigned int prepare;
> + unsigned int hpd_absent_delay;
> unsigned int enable;
> unsigned int disable;
> unsigned int unprepare;
> @@ -79,6 +82,7 @@ struct panel_simple {
> struct drm_panel base;
> bool prepared;
> bool enabled;
> + bool no_hpd;
>
> const struct panel_desc *desc;
>
> @@ -202,6 +206,7 @@ static int panel_simple_unprepare(struct drm_panel *panel)
> static int panel_simple_prepare(struct drm_panel *panel)
> {
> struct panel_simple *p = to_panel_simple(panel);
> + unsigned int delay;
> int err;
>
> if (p->prepared)
> @@ -215,8 +220,11 @@ static int panel_simple_prepare(struct drm_panel *panel)
>
> gpiod_set_value_cansleep(p->enable_gpio, 1);
>
> - if (p->desc->delay.prepare)
> - msleep(p->desc->delay.prepare);
> + delay = p->desc->delay.prepare;
> + if (p->no_hpd)
> + delay += p->desc->delay.hpd_absent_delay;
> + if (delay)
> + msleep(delay);
>
> p->prepared = true;
>
> @@ -305,6 +313,8 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
> panel->prepared = false;
> panel->desc = desc;
>
> + panel->no_hpd = of_property_read_bool(dev->of_node, "no-hpd");
> +
> panel->supply = devm_regulator_get(dev, "power");
> if (IS_ERR(panel->supply))
> return PTR_ERR(panel->supply);
> --
> 2.19.1.568.g152ad8e336-goog
>
--
Sean Paul, Software Engineer, Google / Chromium OS
next prev parent reply other threads:[~2018-10-26 14:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-25 22:21 [PATCH v2 1/6] dt-bindings: drm/panel: simple: Add no-hpd property Douglas Anderson
2018-10-25 22:21 ` [PATCH v2 2/6] drm/panel: simple: Support panels with HPD where HPD isn't connected Douglas Anderson
2018-10-26 14:41 ` Sean Paul [this message]
2018-10-25 22:21 ` [PATCH v2 3/6] drm/panel: simple: Add "no-hpd" delay for Innolux TV123WAM Douglas Anderson
2018-10-26 14:41 ` Sean Paul
2018-10-25 22:21 ` [PATCH v2 4/6] drm/bridge: ti-sn65dsi86: Remove the mystery delay Douglas Anderson
2018-10-29 9:03 ` Andrzej Hajda
2018-10-25 22:21 ` [PATCH v2 5/6] dt-bindings: drm/panel: simple: Innolux TV123WAM is actually P120ZDG-BF1 Douglas Anderson
2018-10-26 14:43 ` Sean Paul
2018-10-26 14:46 ` Sean Paul
2018-10-26 15:01 ` Doug Anderson
2018-10-29 9:10 ` Andrzej Hajda
2018-10-25 22:21 ` [PATCH v2 6/6] " Douglas Anderson
2018-10-26 14:44 ` Sean Paul
2018-10-29 16:16 ` [PATCH v2 1/6] dt-bindings: drm/panel: simple: Add no-hpd property Sean Paul
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181026144111.GQ154160@art_vandelay \
--to=sean@poorly.run \
--cc=airlied@linux.ie \
--cc=dianders@chromium.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=jsanka@codeaurora.org \
--cc=laurent.pinchart@ideasonboard.com \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ryandcase@chromium.org \
--cc=seanpaul@chromium.org \
--cc=spanda@codeaurora.org \
--cc=thierry.reding@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).