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From: "Michal Vokáč" <michal.vokac@ysoft.com>
To: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Shawn Guo <shawnguo@kernel.org>
Cc: "Fabio Estevam" <fabio.estevam@nxp.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-fbdev@vger.kernel.org,
	"Michal Vokáč" <michal.vokac@ysoft.com>
Subject: [PATCH 2/2] video: ssd1307fb: Do not hard code active-low reset sequence
Date: Wed, 19 Sep 2018 09:18:44 +0000	[thread overview]
Message-ID: <1537348724-22976-2-git-send-email-michal.vokac@ysoft.com> (raw)
In-Reply-To: <1537348724-22976-1-git-send-email-michal.vokac@ysoft.com>

The SSD130x OLED display reset signal is active low. Now the reset
sequence is implemented in such a way that users are forced to
define reset-gpios as GPIO_ACTIVE_HIGH in DT to make the reset work.

Do not hard code the active-low sequence into the driver but instead
allow the user to specify the gpio as GPIO_ACTIVE_LOW to reflect
the real world.

The only single in-tree user of the display is converted and builds
fine.

Signed-off-by: Michal Vokáč <michal.vokac@ysoft.com>
---
I am not really sure wheater this should be in one commit or the DT
changes should be done in separate commit. Just tell me and I will
split/merge the changes as you want. Thanks.

 arch/arm/boot/dts/imx28-cfa10036.dts | 3 ++-
 drivers/video/fbdev/ssd1307fb.c      | 4 ++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/arm/boot/dts/imx28-cfa10036.dts b/arch/arm/boot/dts/imx28-cfa10036.dts
index e54f5ab..be3406e 100644
--- a/arch/arm/boot/dts/imx28-cfa10036.dts
+++ b/arch/arm/boot/dts/imx28-cfa10036.dts
@@ -11,6 +11,7 @@
 
 /dts-v1/;
 #include "imx28.dtsi"
+#include <dt-bindings/gpio/gpio.h>
 
 / {
 	model = "Crystalfontz CFA-10036 Board";
@@ -95,7 +96,7 @@
 					pinctrl-names = "default";
 					pinctrl-0 = <&ssd1306_cfa10036>;
 					reg = <0x3c>;
-					reset-gpios = <&gpio2 7 0>;
+					reset-gpios = <&gpio2 7 GPIO_ACTIVE_LOW>;
 					solomon,height = <32>;
 					solomon,width = <128>;
 					solomon,page-offset = <0>;
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index e7ae135..7b5bc42 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -728,10 +728,10 @@ static int ssd1307fb_probe(struct i2c_client *client,
 
 	if (par->reset) {
 		/* Reset the screen */
-		gpiod_set_value_cansleep(par->reset, 0);
-		udelay(4);
 		gpiod_set_value_cansleep(par->reset, 1);
 		udelay(4);
+		gpiod_set_value_cansleep(par->reset, 0);
+		udelay(4);
 	}
 
 	if (par->vbat_reg) {
-- 
2.1.4

  reply	other threads:[~2018-09-19  9:18 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-19  9:18 [PATCH 1/2] video: ssd1307fb: Use gpiod_set_value_cansleep() for reset Michal Vokáč
2018-09-19  9:18 ` Michal Vokáč [this message]
2018-09-19 12:12   ` [PATCH 2/2] video: ssd1307fb: Do not hard code active-low reset sequence Fabio Estevam
2018-09-19 12:57     ` Michal Vokáč
2018-09-19 12:11 ` [PATCH 1/2] video: ssd1307fb: Use gpiod_set_value_cansleep() for reset Fabio Estevam

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