Re: [PATCH v4 3/4] drivers/amba: create devices from device tree

On Fri, Jun 10, 2011 at 05:37:37PM -0500, Rob Herring wrote:

On 06/10/2011 05:22 PM, Grant Likely wrote:

quoted

On Fri, Jun 10, 2011 at 03:48:42PM -0500, Rob Herring wrote:

quoted

From: Rob Herring<rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>

Add a function to create amba bus devices (i.e. primecell peripherals) from
device tree nodes. The device tree scanning is done by
of_platform_probe/populate functions which can call of_amba_device_create
based on a match table entry.

Nodes with a "arm,amba-deviceid" property can override the h/w peripheral id
value.

Based on the original work by Jeremy Kerr.

Cc: Jeremy Kerr<redacted>
Cc: Grant Likely<grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>
Cc: linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org
Cc: arnd-r2nGTMty4D4@public.gmane.org
Acked-by: Linus Walleij<redacted>
Signed-off-by: Rob Herring<rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>
---
 Documentation/devicetree/bindings/arm/amba.txt |   21 ++++++++++
 drivers/amba/bus.c                             |   51 ++++++++++++++++++++++++
 include/linux/amba/bus.h                       |   18 ++++++++
 3 files changed, 90 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/arm/amba.txt

diff --git a/Documentation/devicetree/bindings/arm/amba.txt b/Documentation/devicetree/bindings/arm/amba.txt
new file mode 100644
index 0000000..23fde7f
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/amba.txt

@@ -0,0 +1,21 @@
+* ARM Primecell Peripherals
+
+ARM, Ltd. Primecell peripherals have a standard id register that can be used to
+identify the peripheral type, vendor, and revision. This value can be used for
+driver matching.
+
+Required properties:
+
+- compatible : should be a specific value for peripheral and "arm,amba-device"

After recent conversations, I'd like to change this to
"arm,primecell" to better reflect the kind of devices it models.

That did cross my mind as I was writing the doc...

quoted

quoted

+
+Optional properties:
+
+- arm,amba-deviceid : Value to override the h/w value with

Similarly, based on the primecell device documents, this should
probabaly be arm,primecell-periphid.

quoted

+
+Example:
+
+serial@fff36000 {
+	compatible = "arm,pl011", "arm,amba-device";
+	arm,amba-deviceid =<0x00341011>;
+};
+

diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index d74926e..19f712b 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c

@@ -13,6 +13,11 @@
 #include<linux/string.h>
 #include<linux/slab.h>
 #include<linux/io.h>
+#include<linux/of.h>
+#include<linux/of_irq.h>
+#include<linux/of_address.h>
+#include<linux/of_device.h>
+#include<linux/of_platform.h>
 #include<linux/pm.h>
 #include<linux/pm_runtime.h>
 #include<linux/amba/bus.h>

@@ -785,3 +790,49 @@ EXPORT_SYMBOL(amba_device_unregister);
 EXPORT_SYMBOL(amba_find_device);
 EXPORT_SYMBOL(amba_request_regions);
 EXPORT_SYMBOL(amba_release_regions);
+
+#ifdef CONFIG_OF
+int of_amba_device_create(struct device_node *node, struct device *parent)
+{
+	struct amba_device *dev;
+	const void *prop;
+	int i, ret;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	/* setup generic device info */
+	dev->dev.coherent_dma_mask = ~0;
+	dev->dev.of_node = node;
+	dev->dev.parent = parent;
+	of_device_make_bus_id(&dev->dev);
+
+	/* setup amba-specific device info */
+	dev->dma_mask = ~0;
+
+	/* Allow the arm,amba-deviceid value to override the h/w value */
+	prop = of_get_property(node, "arm,amba-deviceid", NULL);
+	if (prop)
+		dev->periphid = of_read_ulong(prop, 1);
+
+	/* Decode the IRQs and address ranges */
+	for (i = 0; i<  AMBA_NR_IRQS; i++)
+		dev->irq[i] = irq_of_parse_and_map(node, i);
+
+	ret = of_address_to_resource(node, 0,&dev->res);
+	if (ret)
+		goto err_free;
+
+	ret = amba_device_register(dev,&iomem_resource);
+	if (ret)
+		goto err_free;
+
+	return 0;
+
+err_free:
+	kfree(dev);
+	return ret;
+}
+

Yeah, I think this looks like the right thing to do.  I'll pick it up
into devicetree/test and probably move it to devicetree/arm in the
near future after testing a bit.

Okay, I'll respin with your and Arnd's comments.

Actually, hold off.  I'm working on it right now so I can get it into
my tree.  I'll take care of the respin.

g.