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    Subject[RFC PATCH 07/11] dt/platform: allow device name to be overridden
    From
    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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