Hi, Matthias:

On Thu, 2017-11-23 at 09:30 +0100, Matthias Brugger wrote:

On 11/23/2017 06:48 AM, CK Hu wrote:

quoted

Hi, Matthias:

On Tue, 2017-11-14 at 22:41 +0100, Matthias Brugger wrote:

quoted

With the mtk-mmsys MFD device in place, we switch the probing for
mt2701 from device-tree to mfd.

Signed-off-by: Matthias Brugger <mbrugger@suse.com>
---
 drivers/gpu/drm/mediatek/mtk_drm_drv.c | 32 +++++++++++++++++++++++++-------
 1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index dd249cf5121e..5a263aa3ab6e 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c

@@ -21,6 +21,7 @@
 #include <drm/drm_of.h>
 #include <linux/component.h>
 #include <linux/iommu.h>
+#include <linux/mfd/mmsys.h>
 #include <linux/mfd/syscon.h>
 #include <linux/of_address.h>
 #include <linux/of_platform.h>

@@ -392,9 +393,10 @@ static const struct of_device_id mtk_ddp_comp_dt_ids[] = {
 
 static int mtk_drm_probe(struct platform_device *pdev)
 {
+	struct mmsys_dev *mmsys_private;
 	struct device *dev = &pdev->dev;
 	struct mtk_drm_private *private;
-	struct device_node *node;
+	struct device_node *node, *parent_node;
 	struct component_match *match = NULL;
 	int ret;
 	int i;

@@ -407,12 +409,23 @@ static int mtk_drm_probe(struct platform_device *pdev)
 	INIT_WORK(&private->commit.work, mtk_atomic_work);
 	private->data = of_device_get_match_data(dev);
 
-	private->config_regs = syscon_node_to_regmap(dev->of_node);
-	if (IS_ERR(private->config_regs))
-		return PTR_ERR(private->config_regs);
+	/* Check if called from mfd */
+	if (!dev->of_node) {
+		mmsys_private = dev_get_drvdata(pdev->dev.parent);

Why do you directly access parent's driver data? You just need the
device node of mmsys, maybe you could refer to [1].

[1]
https://elixir.free-electrons.com/linux/latest/source/drivers/reset/reset-berlin.c#L78

The difference is, that the driver you mentioned gets probed via device tree
matching, while we get invoked here through the id_table. So there is no device
node (the if actually checkes for pdev->dev.of_node to identify exactly this case).

Regards,
Matthias

Yes, you are right. So

Acked-by: CK Hu <redacted>

Regards,
CK

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