[PATCH 2/2] video: ssd1307fb: Do not hard code active-low reset sequence

From: Michal VokÃÄ
Date: Wed Sep 19 2018 - 05:19:12 EST


The SSD130x OLEDÂdisplay 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 VokÃÄ <michal.vokac@xxxxxxxxx>
---
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