Re: [PATCH v2] driver core: platform_bus: allow runtime override of dev_pm_ops
From: Grant Likely <hidden>
Date: 2010-08-25 07:30:32
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On Mon, Aug 23, 2010 at 11:18 AM, Kevin Hilman [off-list ref] wrote:
Currently, the platform_bus allows customization of several of the busses dev_pm_ops methods by using weak symbols so that platform code can override them. The weak-symbol approach is not scalable when wanting to support multiple platforms in a single kernel binary. Instead, provide __init methods for platform code to customize the dev_pm_ops methods at runtime. NOTE: after these dynamic methods are merged, the weak symbols should be removed from drivers/base/platform.c. AFAIK, this will only affect SH and sh-mobile which should be converted to use this runtime approach instead of the weak symbols. After SH & sh-mobile are converted, the weak symobols could be removed. Tested on OMAP3. Cc: Grant Likely <redacted> Cc: Magnus Damm <magnus.damm@gmail.com> Signed-off-by: Kevin Hilman <redacted>
Looks good to me. A handful of nitpicks below, I don't know if Greg will want you to respin for these or not. Feel free to add my acked-by line though: Acked-by: Grant Likely <redacted>
quoted hunk ↗ jump to hunk
--- drivers/base/platform.c | 35 +++++++++++++++++++++++++++++++++++ include/linux/platform_device.h | 3 +++ 2 files changed, 38 insertions(+), 0 deletions(-)diff --git a/drivers/base/platform.c b/drivers/base/platform.c index c6c933f..e40a773 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c@@ -976,6 +976,41 @@ struct bus_type platform_bus_type = {}; EXPORT_SYMBOL_GPL(platform_bus_type); +/** + * platform_bus_get_pm_ops: return pointer to busses dev_pm_ops
Nit: first line of kerneldoc format should look like this: /** * platform_bus_get_pm_ops() - return pointer to busses dev_pm_ops
+ *
+ * This function can be used by platform code to get the current
+ * set of dev_pm_ops functions used by the platform_bus_type.
+ */
+const struct dev_pm_ops * __init platform_bus_get_pm_ops(void)
+{
+ return platform_bus_type.pm;
+}
+
+/**
+ * platform_bus_set_pm_ops: update dev_pm_ops for the platform_bus_type
+ *
+ * @pm: pointer to new dev_pm_ops struct to be used for platform_bus_type
+ *
+ * Platform code can override the dev_pm_ops methods of
+ * platform_bus_type by using this function. It is expected that
+ * platform code will first do a platform_bus_get_pm_ops(), then
+ * kmemdup it, then customize selected methods and pass a pointer to
+ * the new struct dev_pm_ops to this function.
+ *
+ * Since platform-specific code is customizing methods for *all*
+ * devices (not just platform-specific devices) it is expected that
+ * any custom overrides of these functions will keep existing behavior
+ * and simply extend it. For example, any customization of the
+ * runtime PM methods should continue to call the pm_generic_*
+ * functions as the default ones do in addition to the
+ * platform-specific behavior.
+ */
+void __init platform_bus_set_pm_ops(struct dev_pm_ops *pm)nit: const struct dev_pm_ops would be appropriate
quoted hunk ↗ jump to hunk
+{ + platform_bus_type.pm = pm; +} + int __init platform_bus_init(void) { int error;diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h index d7ecad0..cd55d39 100644 --- a/include/linux/platform_device.h +++ b/include/linux/platform_device.h@@ -138,6 +138,9 @@ extern struct platform_device *platform_create_bundle(struct platform_driver *drstruct resource *res, unsigned int n_res, const void *data, size_t size); +extern const struct dev_pm_ops * __init platform_bus_get_pm_ops(void); +extern void __init platform_bus_set_pm_ops(struct dev_pm_ops *pm);
The __init annotations should only appear in the .c file, not the header. Cheers, g.