linux-kernel - [PATCH v2 2/3] video: ssd1307fb: Do not hard code active-low reset sequence

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Date:   Wed, 19 Sep 2018 15:17:28 +0200
From:   Michal Vokáč <michal.vokac@...ft.com>
To:     Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Shawn Guo <shawnguo@...nel.org>
Cc:     Fabio Estevam <fabio.estevam@....com>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-fbdev@...r.kernel.org,
        Michal Vokáč <michal.vokac@...ft.com>
Subject: [PATCH v2 2/3] video: ssd1307fb: Do not hard code active-low reset sequence

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 <michal.vokac@...ft.com>
---
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