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Commit 5de1540b authored by Grant Likely's avatar Grant Likely
Browse files

drivers/amba: create devices from device tree 



Add a function to create amba_devices (i.e. primecell peripherals)
from device tree nodes. The device tree scanning is done by the
of_platform_populate() function which can call of_amba_device_create
based on a match table entry.

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

Based on the original work by Jeremy Kerr.

Signed-off-by: default avatarJeremy Kerr <jeremy.kerr@canonical.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarRob Herring <rob.herring@calxeda.com>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
[grant.likely: add Jeremy's original s-o-b line, changes from review
               comments, and moved all code to drivers/of/platform.c]
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent 29d4f8a4

Documentation/devicetree/bindings/arm/primecell.txt

0 → 100644
+21 −0
Original line number Diff line number Diff line 
* 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,primecell"



Optional properties:



- arm,primecell-periphid : Value to override the h/w value with



Example:



serial@fff36000 {

	compatible = "arm,pl011", "arm,primecell";

	arm,primecell-periphid = <0x00341011>;

};

drivers/of/platform.c

+71 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
 */

#include <linux/errno.h>

#include <linux/module.h>

#include <linux/amba/bus.h>

#include <linux/device.h>

#include <linux/dma-mapping.h>

#include <linux/slab.h>
@@ -217,6 +218,71 @@ struct platform_device *of_platform_device_create(struct device_node *np, 
}

EXPORT_SYMBOL(of_platform_device_create);



#ifdef CONFIG_ARM_AMBA

static struct amba_device *of_amba_device_create(struct device_node *node,

						 const char *bus_id,

						 void *platform_data,

						 struct device *parent)

{

	struct amba_device *dev;

	const void *prop;

	int i, ret;



	pr_debug("Creating amba device %s\n", node->full_name);



	if (!of_device_is_available(node))

		return NULL;



	dev = kzalloc(sizeof(*dev), GFP_KERNEL);

	if (!dev)

		return NULL;



	/* setup generic device info */

	dev->dev.coherent_dma_mask = ~0;

	dev->dev.of_node = of_node_get(node);

	dev->dev.parent = parent;

	dev->dev.platform_data = platform_data;

	if (bus_id)

		dev_set_name(&dev->dev, "%s", bus_id);

	else

		of_device_make_bus_id(&dev->dev);



	/* setup amba-specific device info */

	dev->dma_mask = ~0;



	/* Allow the HW Peripheral ID to be overridden */

	prop = of_get_property(node, "arm,primecell-periphid", 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 dev;



err_free:

	kfree(dev);

	return NULL;

}

#else /* CONFIG_ARM_AMBA */

static struct amba_device *of_amba_device_create(struct device_node *node,

						 const char *bus_id,

						 void *platform_data,

						 struct device *parent)

{

	return NULL;

}

#endif /* CONFIG_ARM_AMBA */



/**

 * of_platform_bus_create() - Create a device for a node and its children.

 * @bus: device node of the bus to instantiate
@@ -242,6 +308,11 @@ static int of_platform_bus_create(struct device_node *bus, 
		return 0;

	}



	if (of_device_is_compatible(bus, "arm,primecell")) {

		of_amba_device_create(bus, NULL, NULL, parent);

		return 0;

	}



	dev = of_platform_device_create(bus, NULL, parent);

	if (!dev || !of_match_node(matches, bus))

		return 0;