platform: introduce module id table for platform devices

Now platform_device is being widely used on SoC processors where the
peripherals are attached to the system bus, which is simple enough.

However, silicon IPs for these SoCs are usually shared heavily across
a family of processors, even products from different companies.  This
makes the original simple driver name based matching insufficient, or
simply not straight-forward.

Introduce a module id table for platform devices, and makes it clear
that a platform driver is able to support some shared IP and handle
slight differences across different platforms (by 'driver_data').
Module alias is handled automatically when a MODULE_DEVICE_TABLE()
is defined.

To not disturb the current platform drivers too much, the matched id
entry is recorded and can be retrieved by platform_get_device_id().

Signed-off-by: Eric Miao <eric.miao@marvell.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 22 insertions, 1 deletions

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 62a8768d96b..ec993aa6a2c 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -584,10 +584,25 @@ static int platform_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
         struct platform_device  *pdev = to_platform_device(dev);
 
-        add_uevent_var(env, "MODALIAS=platform:%s", pdev->name);
+        add_uevent_var(env, "MODALIAS=%s%s", PLATFORM_MODULE_PREFIX,
+                (pdev->id_entry) ? pdev->id_entry->name : pdev->name);
         return 0;
 }
 
+static const struct platform_device_id *platform_match_id(
+                        struct platform_device_id *id,
+                        struct platform_device *pdev)
+{
+        while (id->name[0]) {
+                if (strcmp(pdev->name, id->name) == 0) {
+                        pdev->id_entry = id;
+                        return id;
+                }
+                id++;
+        }
+        return NULL;
+}
+
 /**
  * platform_match - bind platform device to platform driver.
  * @dev: device.
@@ -604,7 +619,13 @@ static int platform_uevent(struct device *dev, struct kobj_uevent_env *env)
 static int platform_match(struct device *dev, struct device_driver *drv)
 {
         struct platform_device *pdev = to_platform_device(dev);
+        struct platform_driver *pdrv = to_platform_driver(drv);
+
+        /* match against the id table first */
+        if (pdrv->id_table)
+                return platform_match_id(pdrv->id_table, pdev) != NULL;
 
+        /* fall-back to driver name match */
         return (strcmp(pdev->name, drv->name) == 0);
 }