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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>,
        Daniel Vetter <daniel@ffwll.ch>,
        David Airlie <airlied@gmail.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        dri-devel@lists.freedesktop.org
Subject: [PATCH 3/3] drm/ssd130x: Change "solomon,page-offset" property default value
Date:   Thu, 16 Nov 2023 19:07:39 +0100
Message-ID: <20231116180743.2763021-3-javierm@redhat.com>
In-Reply-To: <20231116180743.2763021-1-javierm@redhat.com>
References: <20231116180743.2763021-1-javierm@redhat.com>
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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 emulated 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/gpu/drm/solomon/ssd130x.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c
index bef293922b98..8944129a8e0b 100644
--- a/drivers/gpu/drm/solomon/ssd130x.c
+++ b/drivers/gpu/drm/solomon/ssd130x.c
@@ -1453,7 +1453,7 @@ static void ssd130x_parse_properties(struct ssd130x_device *ssd130x)
 		ssd130x->height = ssd130x->device_info->default_height;
 
 	if (device_property_read_u32(dev, "solomon,page-offset", &ssd130x->page_offset))
-		ssd130x->page_offset = 1;
+		ssd130x->page_offset = 0;
 
 	if (device_property_read_u32(dev, "solomon,col-offset", &ssd130x->col_offset))
 		ssd130x->col_offset = 0;
-- 
2.41.0