[PATCH] drm/rockchip: rgb: don't count non-existent devices when determining subdrivers

From: Heiko Stuebner <heiko@sntech.de>
To: hjc@rock-chips.com
Cc: dri-devel@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	miquel.raynal@bootlin.com,
	christoph.muellner@theobroma-systems.com, heiko@sntech.de,
	Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Subject: [PATCH] drm/rockchip: rgb: don't count non-existent devices when determining subdrivers
Date: Tue, 21 Jan 2020 23:48:28 +0100	[thread overview]
Message-ID: <20200121224828.4070067-1-heiko@sntech.de> (raw)

From: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>

rockchip_drm_endpoint_is_subdriver() may also return error codes.
For example if the target-node is in the disabled state, so no
platform-device is getting created for it.

In that case current code would count that as external rgb device,
which in turn would make probing the rockchip-drm device fail.

So only count the target as rgb device if the function actually
returns 0.

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
---
 drivers/gpu/drm/rockchip/rockchip_rgb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_rgb.c b/drivers/gpu/drm/rockchip/rockchip_rgb.c
index ae730275a34f..79a7e60633e0 100644
--- a/drivers/gpu/drm/rockchip/rockchip_rgb.c
+++ b/drivers/gpu/drm/rockchip/rockchip_rgb.c
@@ -98,7 +98,8 @@ struct rockchip_rgb *rockchip_rgb_init(struct device *dev,
 		if (of_property_read_u32(endpoint, "reg", &endpoint_id))
 			endpoint_id = 0;
 
-		if (rockchip_drm_endpoint_is_subdriver(endpoint) > 0)
+		/* if subdriver (> 0) or error case (< 0), ignore entry */
+		if (rockchip_drm_endpoint_is_subdriver(endpoint) != 0)
 			continue;
 
 		child_count++;
-- 
2.24.1

