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

[Grant Likely]

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.

> +
> +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.

> +#endif /* CONFIG_OF */
> diff --git a/include/linux/amba/bus.h b/include/linux/amba/bus.h
> index fcbbe71..0177274 100644
> --- a/include/linux/amba/bus.h
> +++ b/include/linux/amba/bus.h
> @@ -24,6 +24,7 @@
>  #define AMBA_CID	0xb105f00d
>  
>  struct clk;
> +struct device_node;
>  
>  struct amba_device {
>  	struct device		dev;
> @@ -63,6 +64,7 @@ extern struct bus_type amba_bustype;
>  #define amba_get_drvdata(d)	dev_get_drvdata(&d->dev)
>  #define amba_set_drvdata(d,p)	dev_set_drvdata(&d->dev, p)
>  
> +#ifdef CONFIG_ARM_AMBA
>  int amba_driver_register(struct amba_driver *);
>  void amba_driver_unregister(struct amba_driver *);
>  int amba_device_register(struct amba_device *, struct resource *);
> @@ -94,4 +96,20 @@ void amba_release_regions(struct amba_device *);
>  #define amba_manf(d)	AMBA_MANF_BITS((d)->periphid)
>  #define amba_part(d)	AMBA_PART_BITS((d)->periphid)
>  
> +#ifdef CONFIG_OF
> +int of_amba_device_create(struct device_node *node, struct device *parent);
> +#endif
> +
> +#else
> +
> +#ifdef CONFIG_OF
> +static inline int of_amba_device_create(struct device_node *node, 
> +					struct device *parent)
> +{
> +	return 0;
> +}
> +#endif
> +
> +#endif /* CONFIG_ARM_AMBA */
> +
>  #endif
> -- 
> 1.7.4.1
>