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List:       linux-fbdev
Subject:    [PATCH v2 2/3] fbdev: omap2: panel-dpi: make (limited) use of a reset gpio
From:       Uwe Kleine-König  <u.kleine-koenig () pengutronix ! de>
Date:       2015-12-20 11:13:21
Message-ID: 1450610002-10531-3-git-send-email-u.kleine-koenig () pengutronix ! de
[Download RAW message or body]

Some displays have a reset input. To assert that the display is
functional the reset gpio must be deasserted.

Teach the driver to get and drive such a gpio accordingly.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
--
Changes since (implicit) v1, sent with
Message-Id: 1449753107-11410-4-git-send-email-uwe@kleine-koenig.org :

 - never assert reset because there are too many different panels with
   too many different needs for their reset.
 - split out dt binding changes
 - reword commit log
---
 drivers/video/fbdev/omap2/displays-new/panel-dpi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c \
b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c index e780fd4f8b46..201a1c1a6f42 \
                100644
--- a/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
+++ b/drivers/video/fbdev/omap2/displays-new/panel-dpi.c
@@ -213,6 +213,16 @@ static int panel_dpi_probe_of(struct platform_device *pdev)
 
 	ddata->enable_gpio = gpio;
 
+	/*
+	 * Many different panels are supported by this driver and there are
+	 * probably very different needs for their reset pins in regards to
+	 * timing and order relative to the enable gpio. So for now it's just
+	 * ensured that the reset line isn't active.
+	 */
+	gpio = devm_gpiod_get_optional(&pdev->dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(gpio))
+		return PTR_ERR(gpio);
+
 	ddata->backlight_gpio = -ENOENT;
 
 	r = of_get_display_timing(node, "panel-timing", &timing);
-- 
2.6.2

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