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Subject[RFC PATCH 07/11] dt/platform: allow device name to be overridden
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Date
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 <grant.likely@secretlab.ca>
---
drivers/of/platform.c | 73 +++++++++++++++++++++++++++++++++++++------
include/linux/of_platform.h | 35 ++++++++++++++++++++
2 files changed, 98 insertions(+), 10 deletions(-)
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 4192ddc..e75af39 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -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;

@@ -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
@@ -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
@@ -284,6 +304,28 @@ 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
* @matches: match table for bus nodes
@@ -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 */
@@ -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;
@@ -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;
}
@@ -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;
@@ -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;
}
diff --git a/include/linux/of_platform.h b/include/linux/of_platform.h
index 8390233..5a6f458 100644
--- a/include/linux/of_platform.h
+++ b/include/linux/of_platform.h
@@ -20,6 +20,40 @@
#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.
*
* An of_platform_driver driver is attached to a basic platform_device on
@@ -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 */



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