[PATCH] Revert "drm/imx: Remove of_node assignment from ipuv3-crtc driver probe"

[Fabio Estevam]

Commit 407c9eba789767 ("drm/imx: Remove of_node assignment from ipuv3-crtc
driver probe") causes the IPU to be non-functional, so better to 
revert it to avoid such regression.

This reverts commit 407c9eba789767feb68b42eb2d65db68584e06c0.

Cc: <stable at vger.kernel.org> # 4.4.x
Signed-off-by: Fabio Estevam <fabio.estevam at nxp.com>
---
 drivers/gpu/drm/imx/ipuv3-crtc.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/gpu/drm/imx/ipuv3-crtc.c b/drivers/gpu/drm/imx/ipuv3-crtc.c
index dee8e8b..006753d 100644
--- a/drivers/gpu/drm/imx/ipuv3-crtc.c
+++ b/drivers/gpu/drm/imx/ipuv3-crtc.c
@@ -520,6 +520,28 @@ err_put_resources:
        return ret;
 }

+static struct device_node *ipu_drm_get_port_by_id(struct device_node *parent,
+                                                 int port_id)
+{
+       struct device_node *port;
+       int id, ret;
+
+       port = of_get_child_by_name(parent, "port");
+       while (port) {
+               ret = of_property_read_u32(port, "reg", &id);
+               if (!ret && id == port_id)
+                       return port;
+
+               do {
+                       port = of_get_next_child(parent, port);
+                       if (!port)
+                               return NULL;
+               } while (of_node_cmp(port->name, "port"));
+       }
+
+       return NULL;
+}
+
 static int ipu_drm_bind(struct device *dev, struct device *master, void *data)
 {
        struct ipu_client_platformdata *pdata = dev->platform_data;
@@ -562,11 +584,23 @@ static const struct component_ops ipu_crtc_ops = {
 static int ipu_drm_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
+       struct ipu_client_platformdata *pdata = dev->platform_data;
        int ret;

        if (!dev->platform_data)
                return -EINVAL;

+       if (!dev->of_node) {
+               /* Associate crtc device with the corresponding DI port node */
+               dev->of_node = ipu_drm_get_port_by_id(dev->parent->of_node,
+                                                     pdata->di + 2);
+               if (!dev->of_node) {
+                       dev_err(dev, "missing port@%d node in %s\n",
+                               pdata->di + 2, dev->parent->of_node->full_name);
+                       return -ENODEV;
+               }
+       }
+
        ret = dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
        if (ret)
                return ret;
-- 
1.9.1