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

[Rob Herring]

On 06/10/2011 05:22 PM, Grant Likely wrote:
> On Fri, Jun 10, 2011 at 03:48:42PM -0500, Rob Herring wrote:
>> From: Rob Herring<rob.herring at calxeda.com>
>>
>> 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<jeremy.kerr at canonical.com>
>> Cc: Grant Likely<grant.likely at secretlab.ca>
>> Cc: linux at arm.linux.org.uk
>> Cc: arnd at arndb.de
>> Acked-by: Linus Walleij<linus.walleij at linaro.org>
>> Signed-off-by: Rob Herring<rob.herring at calxeda.com>
>> ---
>>   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...

>
>> +
>> +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.
>
>> +
>> +Example:
>> +
>> +serial at 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.

Rob

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