Hi Marc,

Marc Zyngier [off-list ref] wrote on Thu, 28 Jun 2018 13:45:09
+0100:

On 22/06/18 16:14, Miquel Raynal wrote:

quoted

The ICU can handle several type of interrupt, each of them being handled
differently on AP side. On CP side, the ICU should be able to make the
distinction between each interrupt group by pointing to the right parent.

This is done through the introduction of new bindings, presenting the ICU
node as the parent of multiple ICU sub-nodes, each of them being an
interrupt type with a different interrupt parent. ICU interrupt 'clients'
now directly point to the right sub-node, avoiding the need for the extra
ICU_GRP_* parameter.

ICU subnodes are probed automatically with devm_platform_populate(). If
the node as no child, the probe function for NSRs will still be called
'manually' in order to preserve backward compatibility with DT using the
old binding.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 drivers/irqchip/irq-mvebu-icu.c | 88 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 74 insertions(+), 14 deletions(-)

diff --git a/drivers/irqchip/irq-mvebu-icu.c b/drivers/irqchip/irq-mvebu-icu.c
index 24d45186eb6b..f7c2ede9c222 100644
--- a/drivers/irqchip/irq-mvebu-icu.c
+++ b/drivers/irqchip/irq-mvebu-icu.c

@@ -43,6 +43,7 @@ struct mvebu_icu {
 	struct regmap *regmap;
 	struct device *dev;
 	atomic_t initialized;
+	bool legacy_bindings;
 };
 
 struct mvebu_icu_irq_data {

@@ -51,6 +52,30 @@ struct mvebu_icu_irq_data {
 	unsigned int type;
 };
 
+static struct mvebu_icu *mvebu_icu_dev_get_drvdata(struct platform_device *pdev)
+{
+	struct mvebu_icu *icu;
+
+	/*
+	 * Device data being populated means we should be using legacy bindings.
+	 * Using the _parent_ device data means we should be using new bindings.
+	 */
+	icu = dev_get_drvdata(&pdev->dev);
+	if (icu) {
+		if (!icu->legacy_bindings)
+			return ERR_PTR(-EINVAL);
+	} else {
+		icu = dev_get_drvdata(pdev->dev.parent);
+		if (!icu)
+			return ERR_PTR(-ENODEV);
+
+		if (icu->legacy_bindings)
+			return ERR_PTR(-EINVAL);
+	}  

Doesn't this make legacy_bindings completely redundant? Either the
pointer is !NULL in the device, and this is using a legacy binging, or
it is stored in the parent, and this is a new binding. You could even
have a helper for that:

static bool is_legacy(struct platform_device *pdev)
{
	return !dev_get_drvdata(&pdev->dev);
}

The driver really doesn't need to be defending against itself, if
anything, and it would save you quite a bit of error handling in the
callers of this function.

I simplified the sanity checks but I had to keep an icu->is_legacy
boolean because the above function would not have worked, for instance,
in the *_translate() hook. As this hook does not receive a struct
device * (or platform_device) as parameter, I tried to use icu->dev
instead. This cannot work as it always points to the device having the
driver data attached.

Please tell me if the next version fits what you expect.

Thanks,
Miqu?l