On Fri, 2017-05-12 at 17:05 +0200, Matthias Brugger wrote:
>
> On 12/05/17 05:22, Minghsiu Tsai wrote:
> > From: Daniel Kurtz <djkurtz@xxxxxxxxxxxx>
> >
> > If the mdp_* nodes are under an mdp sub-node, their corresponding
> > platform device does not automatically get its iommu assigned properly.
> >
> > Fix this by moving the mdp component nodes up a level such that they are
> > siblings of mdp and all other SoC subsystems. This also simplifies the
> > device tree.
> >
> > Although it fixes iommu assignment issue, it also break compatibility
> > with old device tree. So, the patch in driver is needed to iterate over
> > sibling mdp device nodes, not child ones, to keep driver work properly.
> >
>
> Couldn't we preserve backwards compatibility by doing something like this:
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> index 9e4eb7dcc424..277d8fe6eb76 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> @@ -103,7 +103,7 @@ static int mtk_mdp_probe(struct platform_device *pdev)
> {
> struct mtk_mdp_dev *mdp;
> struct device *dev = &pdev->dev;
> - struct device_node *node;
> + struct device_node *node, *parent;
> int i, ret = 0;
>
> mdp = devm_kzalloc(dev, sizeof(*mdp), GFP_KERNEL);
> @@ -117,8 +117,14 @@ static int mtk_mdp_probe(struct platform_device *pdev)
> mutex_init(&mdp->lock);
> mutex_init(&mdp->vpulock);
>
> + /* Old dts had the components as child nodes */
> + if (of_get_next_child(dev->of_node, NULL))
> + parent = dev->of_node;
> + else
> + parent = dev->of_node->parent;
> +
> /* Iterate over sibling MDP function blocks */
> - for_each_child_of_node(dev->of_node, node) {
> + for_each_child_of_node(parent, node) {
> const struct of_device_id *of_id;
> enum mtk_mdp_comp_type comp_type;
> int comp_id;
>
> Maybe even by putting a warning in the if branch to make sure, people
> are aware of their out-of-date device tree blobs.
>
> Regards,
> Matthias
>
Hi Matthias,
It is a good idea to do compatible in such a way and put a warning the
device tree is out of date. People can find out cause soon if device
tree is old.
I modify the code as below:
+ /* Old dts had the components as child nodes */
+ if (of_get_next_child(dev->of_node, NULL)) {
+ parent = dev->of_node;
+ dev_warn(dev, "device tree is out of date\n");
+ } else {
+ parent = dev->of_node->parent;
+ }
Will you upload it in a separate patch?
If not, I can merge it in my patch series and upload v4.
Best Regards,
Ming Hsiu
> > Signed-off-by: Daniel Kurtz <djkurtz@xxxxxxxxxxxx>
> > Signed-off-by: Minghsiu Tsai <minghsiu.tsai@xxxxxxxxxxxx>
> >
> > ---
> > drivers/media/platform/mtk-mdp/mtk_mdp_core.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> > index 9e4eb7d..a5ad586 100644
> > --- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> > +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> > @@ -118,7 +118,7 @@ static int mtk_mdp_probe(struct platform_device *pdev)
> > mutex_init(&mdp->vpulock);
> >
> > /* Iterate over sibling MDP function blocks */
> > - for_each_child_of_node(dev->of_node, node) {
> > + for_each_child_of_node(dev->of_node->parent, node) {
> > const struct of_device_id *of_id;
> > enum mtk_mdp_comp_type comp_type;
> > int comp_id;
> >
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