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Date: Wed, 9 Sep 2020 13:38:25 +0200
From: Linus Walleij <linus.walleij@...aro.org>
To: Paul Cercueil <paul@...pouillou.net>
Cc: Thierry Reding <thierry.reding@...il.com>,
Sam Ravnborg <sam@...nborg.org>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Rob Herring <robh+dt@...nel.org>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>,
Noralf Tronnes <noralf@...nnes.org>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
od@...c.me,
"open list:DRM PANEL DRIVERS" <dri-devel@...ts.freedesktop.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 6/6] drm/panel: Add Ilitek ILI9341 DBI panel driver
Hi Paul,
just a drive-by comment:
On Sat, Aug 22, 2020 at 6:33 PM Paul Cercueil <paul@...pouillou.net> wrote:
> + gpiod_set_value_cansleep(priv->reset_gpiod, 0);
> + usleep_range(20, 1000);
> + gpiod_set_value_cansleep(priv->reset_gpiod, 1);
This implies that the reset line is active low.
I would specify in the DT GPIO handle that it is active low
and invert the above.
So:
reset-gpios = <&gpio 4 GPIO_ACTIVE_LOW>;
gpiod_set_value_cansleep(priv->reset_gpiod, 1);
usleep_range(20, 1000);
gpiod_set_value_cansleep(priv->reset_gpiod, 0);
> + priv->reset_gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> + if (IS_ERR(priv->reset_gpiod)) {
> + dev_err(dev, "Couldn't get our reset GPIO\n");
> + return PTR_ERR(priv->reset_gpiod);
> + }
This would then fetch the GPIO as asserted (device in reset)
unless changed, but that may be the right thing to do actually.
> +static const struct ili9341_pdata yx240qv29_pdata = {
> + .mode = { DRM_SIMPLE_MODE(240, 320, 37, 49) },
> + .width_mm = 0, // TODO
> + .height_mm = 0, // TODO
When nothing else works and data sheets are incomplete I
just take out a ruler and measure on the actual device.
Yours,
Linus Walleij
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