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dt/platform: allow device name to be overridden
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Some platform code has specific requirements on the naming of devices.
This patch allows callers of of_platform_populate() to provide a
device name lookup table.

Signed-off-by: Grant Likely <[email protected]>
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@glikely
glikely committed Jun 21, 2011
1 parent 5de1540 commit 15c3597
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Showing 2 changed files with 98 additions and 10 deletions.
73 changes: 63 additions & 10 deletions drivers/of/platform.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -177,17 +177,20 @@ struct platform_device *of_device_alloc(struct device_node *np,
EXPORT_SYMBOL(of_device_alloc);

/**
* of_platform_device_create - Alloc, initialize and register an of_device
* of_platform_device_create_pdata - Alloc, initialize and register an of_device
* @np: pointer to node to create device for
* @bus_id: name to assign device
* @platform_data: pointer to populate platform_data pointer with
* @parent: Linux device model parent device.
*
* Returns pointer to created platform device, or NULL if a device was not
* registered. Unavailable devices will not get registered.
*/
struct platform_device *of_platform_device_create(struct device_node *np,
const char *bus_id,
struct device *parent)
struct platform_device *of_platform_device_create_pdata(
struct device_node *np,
const char *bus_id,
void *platform_data,
struct device *parent)
{
struct platform_device *dev;

Expand All @@ -203,6 +206,7 @@ struct platform_device *of_platform_device_create(struct device_node *np,
#endif
dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
dev->dev.bus = &platform_bus_type;
dev->dev.platform_data = platform_data;

/* We do not fill the DMA ops for platform devices by default.
* This is currently the responsibility of the platform code
Expand All @@ -216,6 +220,22 @@ struct platform_device *of_platform_device_create(struct device_node *np,

return dev;
}

/**
* of_platform_device_create - Alloc, initialize and register an of_device
* @np: pointer to node to create device for
* @bus_id: name to assign device
* @parent: Linux device model parent device.
*
* Returns pointer to created platform device, or NULL if a device was not
* registered. Unavailable devices will not get registered.
*/
struct platform_device *of_platform_device_create(struct device_node *np,
const char *bus_id,
struct device *parent)
{
return of_platform_device_create_pdata(np, bus_id, NULL, parent);
}
EXPORT_SYMBOL(of_platform_device_create);

#ifdef CONFIG_ARM_AMBA
Expand Down Expand Up @@ -283,6 +303,28 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
}
#endif /* CONFIG_ARM_AMBA */

/**
* of_devname_lookup() - Given a device node, lookup the preferred Linux name
*/
static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *lookup,
struct device_node *np)
{
struct resource res;
if (lookup) {
for(; lookup->name != NULL; lookup++) {
if (!of_device_is_compatible(np, lookup->compatible))
continue;
if (of_address_to_resource(np, 0, &res))
continue;
if (res.start != lookup->phys_addr)
continue;
pr_debug("%s: devname=%s\n", np->full_name, lookup->name);
return lookup;
}
}
return NULL;
}

/**
* of_platform_bus_create() - Create a device for a node and its children.
* @bus: device node of the bus to instantiate
Expand All @@ -295,10 +337,14 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
*/
static int of_platform_bus_create(struct device_node *bus,
const struct of_device_id *matches,
const struct of_dev_auxdata *lookup,
struct device *parent, bool strict)
{
const struct of_dev_auxdata *auxdata;
struct device_node *child;
struct platform_device *dev;
const char *bus_id = NULL;
void *platform_data = NULL;
int rc = 0;

/* Make sure it has a compatible property */
Expand All @@ -308,18 +354,24 @@ static int of_platform_bus_create(struct device_node *bus,
return 0;
}

auxdata = of_dev_lookup(lookup, bus);
if (auxdata) {
bus_id = auxdata->name;
platform_data = auxdata->platform_data;
}

if (of_device_is_compatible(bus, "arm,primecell")) {
of_amba_device_create(bus, NULL, NULL, parent);
of_amba_device_create(bus, bus_id, platform_data, parent);
return 0;
}

dev = of_platform_device_create(bus, NULL, parent);
dev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
if (!dev || !of_match_node(matches, bus))
return 0;

for_each_child_of_node(bus, child) {
pr_debug(" create child: %s\n", child->full_name);
rc = of_platform_bus_create(child, matches, &dev->dev, strict);
rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
if (rc) {
of_node_put(child);
break;
Expand Down Expand Up @@ -353,11 +405,11 @@ int of_platform_bus_probe(struct device_node *root,

/* Do a self check of bus type, if there's a match, create children */
if (of_match_node(matches, root)) {
rc = of_platform_bus_create(root, matches, parent, false);
rc = of_platform_bus_create(root, matches, NULL, parent, false);
} else for_each_child_of_node(root, child) {
if (!of_match_node(matches, child))
continue;
rc = of_platform_bus_create(child, matches, parent, false);
rc = of_platform_bus_create(child, matches, NULL, parent, false);
if (rc)
break;
}
Expand Down Expand Up @@ -387,6 +439,7 @@ EXPORT_SYMBOL(of_platform_bus_probe);
*/
int of_platform_populate(struct device_node *root,
const struct of_device_id *matches,
const struct of_dev_auxdata *lookup,
struct device *parent)
{
struct device_node *child;
Expand All @@ -397,7 +450,7 @@ int of_platform_populate(struct device_node *root,
return -EINVAL;

for_each_child_of_node(root, child) {
rc = of_platform_bus_create(child, matches, parent, true);
rc = of_platform_bus_create(child, matches, lookup, parent, true);
if (rc)
break;
}
Expand Down
35 changes: 35 additions & 0 deletions include/linux/of_platform.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,40 @@
#include <linux/of_device.h>
#include <linux/platform_device.h>

/**
* struct of_dev_auxdata - lookup table entry for device names & platform_data
* @compatible: compatible value of node to match against node
* @phys_addr: Start address of registers to match against node
* @name: Name to assign for matching nodes
* @platform_data: platform_data to assign for matching nodes
*
* This lookup table allows the caller of of_platform_populate() to override
* the names of devices when creating devices from the device tree. The table
* should be terminated with an empty entry. It also allows the platform_data
* pointer to be set.
*
* The reason for this functionality is that some Linux infrastructure uses
* the device name to look up a specific device, but the Linux-specific names
* are not encoded into the device tree, so the kernel needs to provide specific
* values.
*
* Note: Using an auxdata lookup table should be considered a last resort when
* converting a platform to use the DT. Normally the automatically generated
* device name will not matter, and drivers should obtain data from the device
* node instead of from an anonymouns platform_data pointer.
*/
struct of_dev_auxdata {
char *compatible;
resource_size_t phys_addr;
char *name;
void *platform_data;
};

/* Macro to simplify populating a lookup table */
#define OF_DEV_AUXDATA(_compat,_phys,_name,_pdata) \
{ .compatible = _compat, .phys_addr = _phys, .name = _name, \
.platform_data = _pdata }

/**
* of_platform_driver - Legacy of-aware driver for platform devices.
*
Expand Down Expand Up @@ -59,6 +93,7 @@ extern int of_platform_bus_probe(struct device_node *root,
struct device *parent);
extern int of_platform_populate(struct device_node *root,
const struct of_device_id *matches,
const struct of_dev_auxdata *lookup,
struct device *parent);
#endif /* !CONFIG_SPARC */

Expand Down

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