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From: Javier Martinez Canillas <javierm@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: "Sahaj Sarup" <sahaj.sarup@linaro.org>,
	"Javier Martinez Canillas" <javierm@redhat.com>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	"Geert Uytterhoeven" <geert@linux-m68k.org>,
	"Helge Deller" <deller@gmx.de>, "Sam Ravnborg" <sam@ravnborg.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org
Subject: [PATCH 2/3] fbdev: ssd1307fb: Change "solomon,page-offset" property default value
Date: Thu, 16 Nov 2023 19:07:38 +0100	[thread overview]
Message-ID: <20231116180743.2763021-2-javierm@redhat.com> (raw)
In-Reply-To: <20231116180743.2763021-1-javierm@redhat.com>

This is used to specify the page start address offset of the display RAM.

The value is used as offset when setting the page start address with the
SSD130X_SET_PAGE_RANGE command, and the driver currently sets its value to
1 if the property is not present in the Device Tree.

But the datasheet mentions that the value on reset for the page start is a
0, so it makes more sense to also have 0 as the default value for the page
offset if the property is not present.

In fact, using a default value of 1 leads to the display not working when
the fbdev is attached to the framebuffer console.

Reported-by: Sahaj Sarup <sahaj.sarup@linaro.org>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---

 drivers/video/fbdev/ssd1307fb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 5ae48e36fccb..34f014bf4994 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -637,7 +637,7 @@ static int ssd1307fb_probe(struct i2c_client *client)
 		par->height = 16;
 
 	if (device_property_read_u32(dev, "solomon,page-offset", &par->page_offset))
-		par->page_offset = 1;
+		par->page_offset = 0;
 
 	if (device_property_read_u32(dev, "solomon,col-offset", &par->col_offset))
 		par->col_offset = 0;
-- 
2.41.0


WARNING: multiple messages have this Message-ID (diff)
From: Javier Martinez Canillas <javierm@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: linux-fbdev@vger.kernel.org,
	"Sahaj Sarup" <sahaj.sarup@linaro.org>,
	"Helge Deller" <deller@gmx.de>,
	"Javier Martinez Canillas" <javierm@redhat.com>,
	dri-devel@lists.freedesktop.org,
	"Geert Uytterhoeven" <geert@linux-m68k.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
	"Sam Ravnborg" <sam@ravnborg.org>
Subject: [PATCH 2/3] fbdev: ssd1307fb: Change "solomon, page-offset" property default value
Date: Thu, 16 Nov 2023 19:07:38 +0100	[thread overview]
Message-ID: <20231116180743.2763021-2-javierm@redhat.com> (raw)
In-Reply-To: <20231116180743.2763021-1-javierm@redhat.com>

This is used to specify the page start address offset of the display RAM.

The value is used as offset when setting the page start address with the
SSD130X_SET_PAGE_RANGE command, and the driver currently sets its value to
1 if the property is not present in the Device Tree.

But the datasheet mentions that the value on reset for the page start is a
0, so it makes more sense to also have 0 as the default value for the page
offset if the property is not present.

In fact, using a default value of 1 leads to the display not working when
the fbdev is attached to the framebuffer console.

Reported-by: Sahaj Sarup <sahaj.sarup@linaro.org>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---

 drivers/video/fbdev/ssd1307fb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 5ae48e36fccb..34f014bf4994 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -637,7 +637,7 @@ static int ssd1307fb_probe(struct i2c_client *client)
 		par->height = 16;
 
 	if (device_property_read_u32(dev, "solomon,page-offset", &par->page_offset))
-		par->page_offset = 1;
+		par->page_offset = 0;
 
 	if (device_property_read_u32(dev, "solomon,col-offset", &par->col_offset))
 		par->col_offset = 0;
-- 
2.41.0


  reply	other threads:[~2023-11-16 18:08 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-16 18:07 [PATCH 1/3] dt-bindings: display: ssd1307fb: Change "solomon,page-offset" default value Javier Martinez Canillas
2023-11-16 18:07 ` [PATCH 1/3] dt-bindings: display: ssd1307fb: Change "solomon, page-offset" " Javier Martinez Canillas
2023-11-16 18:07 ` Javier Martinez Canillas [this message]
2023-11-16 18:07   ` [PATCH 2/3] fbdev: ssd1307fb: Change "solomon, page-offset" property " Javier Martinez Canillas
2023-11-17 21:15   ` [PATCH 2/3] fbdev: ssd1307fb: Change "solomon,page-offset" " Andy Shevchenko
2023-11-17 21:15     ` Andy Shevchenko
2023-11-17 22:18     ` Javier Martinez Canillas
2023-11-17 22:18       ` Javier Martinez Canillas
2023-11-16 18:07 ` [PATCH 3/3] drm/ssd130x: " Javier Martinez Canillas
2023-11-16 18:07   ` [PATCH 3/3] drm/ssd130x: Change "solomon, page-offset" " Javier Martinez Canillas
2023-11-17  8:38   ` [PATCH 3/3] drm/ssd130x: Change "solomon,page-offset" " Maxime Ripard
2023-11-17  8:38     ` Maxime Ripard
2023-11-17  8:59     ` Javier Martinez Canillas
2023-11-17  8:59       ` Javier Martinez Canillas
2023-11-20 15:50 ` [PATCH 1/3] dt-bindings: display: ssd1307fb: Change "solomon,page-offset" " Conor Dooley
2023-11-20 15:50   ` Conor Dooley
2023-11-20 19:37   ` Javier Martinez Canillas
2023-11-20 19:37     ` Javier Martinez Canillas

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