[PATCH v2 1/3] video: ssd1307fb: Use gpiod_set_value_cansleep() for reset

The reset signal can be produced by GPIO expander that can sleep.
In that case the probe function fails. Allow using GPIO expanders for
the reset signal by using the non-atomic gpiod_set_value_cansleep()
function.

Signed-off-by: Michal Vokáč <redacted>
---
v2 changes: none

 drivers/video/fbdev/ssd1307fb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index ba66c02..e7ae135 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c

@@ -728,9 +728,9 @@ static int ssd1307fb_probe(struct i2c_client *client,
 
 	if (par->reset) {
 		/* Reset the screen */
-		gpiod_set_value(par->reset, 0);
+		gpiod_set_value_cansleep(par->reset, 0);
 		udelay(4);
-		gpiod_set_value(par->reset, 1);
+		gpiod_set_value_cansleep(par->reset, 1);
 		udelay(4);
 	}
 

-- 
2.1.4

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.

Signed-off-by: Michal Vokáč <redacted>
---
v2 changes: Split the DT changes into separate patch.

 drivers/video/fbdev/ssd1307fb.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

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

The reset signal of the SSD1306 OLED display is actually active-low.
Adapt the DT to reflect the real world.

Signed-off-by: Michal Vokáč <redacted>
---
v2 changes: New patch in the series

 arch/arm/boot/dts/imx28-cfa10036.dts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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>;

-- 
2.1.4

On 19.9.2018 15:17, Michal Vokáč wrote:

The reset signal can be produced by GPIO expander that can sleep.
In that case the probe function fails. Allow using GPIO expanders for
the reset signal by using the non-atomic gpiod_set_value_cansleep()
function.

Signed-off-by: Michal Vokáč <redacted>

I forgot to add R-by from Fabio from v1, sorry.
I made the respin in a hurry and skipped my pre-submission checklist..

Michal