[PATCH v2 4/5] drm/etnaviv: Add a helper to get the first available GPU device node

[Sui Jingfeng]

This patch make the code in the etnaviv_pdev_probe() less twisted, and it
also make it easier to drop the reference to device node after finished.
Before apply this patch, there is no call to of_node_put() when done. We
should call of_node_put() when done.

Signed-off-by: Sui Jingfeng <suijingf...@loongson.cn>
---
 drivers/gpu/drm/etnaviv/etnaviv_drv.c | 28 ++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_drv.c 
b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
index 8fe39e31d22d..a9a1659840ec 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_drv.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_drv.c
@@ -29,6 +29,17 @@
  * DRM operations:
  */
 
+static struct device_node *etnaviv_of_first_available_node(void)
+{
+       struct device_node *np;
+
+       for_each_compatible_node(np, NULL, "vivante,gc") {
+               if (of_device_is_available(np))
+                       return np;
+       }
+
+       return NULL;
+}
 
 static void load_gpu(struct drm_device *dev)
 {
@@ -597,11 +608,10 @@ static int etnaviv_pdev_probe(struct platform_device 
*pdev)
                        if (!of_device_is_available(core_node))
                                continue;
 
-                       if (!first_node)
-                               first_node = core_node;
-
                        drm_of_component_match_add(&pdev->dev, &match,
                                                   component_compare_of, 
core_node);
+
+                       of_node_put(core_node);
                }
        } else {
                char **names = dev->platform_data;
@@ -634,8 +644,11 @@ static int etnaviv_pdev_probe(struct platform_device *pdev)
         * device as the GPU we found. This assumes that all Vivante
         * GPUs in the system share the same DMA constraints.
         */
-       if (first_node)
+       first_node = etnaviv_of_first_available_node();
+       if (first_node) {
                of_dma_configure(&pdev->dev, first_node, true);
+               of_node_put(first_node);
+       }
 
        return component_master_add_with_match(dev, &etnaviv_master_ops, match);
 }
@@ -709,16 +722,13 @@ static int __init etnaviv_init(void)
         * If the DT contains at least one available GPU device, instantiate
         * the DRM platform device.
         */
-       for_each_compatible_node(np, NULL, "vivante,gc") {
-               if (!of_device_is_available(np))
-                       continue;
+       np = etnaviv_of_first_available_node();
+       if (np) {
                of_node_put(np);
 
                ret = etnaviv_create_platform_device("etnaviv", &etnaviv_drm);
                if (ret)
                        goto unregister_platform_driver;
-
-               break;
        }
 
        return 0;
-- 
2.34.1