Mis-typed omap's list; sorry for the resend On 08/03/2010 04:35 PM, Patrick Pannuto wrote: > Inspiration for this comes from: > http://www.mail-archive.com/linux-omap@xxxxxxxxxxxxxxx/msg31161.html > > INTRO > > As SOCs become more popular, the desire to quickly define a simple, > but functional, bus type with only a few unique properties becomes > desirable. As they become more complicated, the ability to nest these > simple busses and otherwise orchestrate them to match the actual > topology also becomes desirable. > > EXAMPLE USAGE > > /arch/ARCH/MY_ARCH/my_bus.c: > > #include <linux/device.h> > #include <linux/platform_device.h> > > struct bus_type my_bus_type = { > .name = "mybus", > }; > EXPORT_SYMBOL_GPL(my_bus_type); > > struct platform_device sub_bus1 = { > .name = "sub_bus1", > .id = -1, > .dev.bus = &my_bus_type, > } > EXPORT_SYMBOL_GPL(sub_bus1); > > struct platform_device sub_bus2 = { > .name = "sub_bus2", > .id = -1, > .dev.bus = &my_bus_type, > } > EXPORT_SYMBOL_GPL(sub_bus2); > > static int __init my_bus_init(void) > { > int error; > platform_bus_type_init(&my_bus_type); > > error = bus_register(&my_bus_type); > if (error) > return error; > > error = platform_device_register(&sub_bus1); > if (error) > goto fail_sub_bus1; > > error = platform_device_register(&sub_bus2); > if (error) > goto fail_sub_bus2; > > return error; > > fail_sub_bus2: > platform_device_unregister(&sub_bus1); > fail_sub_bus2: > bus_unregister(&my_bus_type); > > return error; > } > postcore_initcall(my_bus_init); > EXPORT_SYMBOL_CPY(my_bus_init); > > /drivers/my_driver.c > static struct platform_driver my_driver = { > .driver = { > .name = "my-driver", > .owner = THIS_MODULE, > .bus = &my_bus_type, > }, > }; > > /somewhere/my_device.c > static struct platform_device my_device = { > .name = "my-device", > .id = -1, > .dev.bus = &my_bus_type, > .dev.parent = &sub_bus_1.dev, > }; > > Notice that for a device / driver, only 3 lines were added to > switch from the platform bus to the new my_bus. This is > especially valuable if we consider supporting a legacy SOCs > and new SOCs where the same driver is used, but may need to > be on either the platform bus or the new my_bus. The above > code then becomes: > > (possibly in a header) > #ifdef CONFIG_MY_BUS > #define MY_BUS_TYPE &my_bus_type > #else > #define MY_BUS_TYPE NULL > #endif > > /drivers/my_driver.c > static struct platform_driver my_driver = { > .driver = { > .name = "my-driver", > .owner = THIS_MODULE, > .bus = MY_BUS_TYPE, > }, > }; > > Which will allow the same driver to easily to used on either > the platform bus or the newly defined bus type. > > This will build a device tree that mirrors the actual configuration: > /sys/bus > |-- my_bus > | |-- devices > | | |-- sub_bus1 -> ../../../devices/platform/sub_bus1 > | | |-- sub_bus2 -> ../../../devices/platform/sub_bus2 > | | |-- my-device -> ../../../devices/platform/sub_bus1/my-device > | |-- drivers > | | |-- my-driver > > I believe this to be a fairly elegant and simple solution to the > problem, but humbly RFC > > -Pat > > Signed-off-by: Patrick Pannuto <ppannuto@xxxxxxxxxxxxxx> > --- > drivers/base/platform.c | 30 ++++++++++++++++++++++++++---- > include/linux/platform_device.h | 2 ++ > 2 files changed, 28 insertions(+), 4 deletions(-) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index 4d99c8b..c86be03 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -241,7 +241,8 @@ int platform_device_add(struct platform_device *pdev) > if (!pdev->dev.parent) > pdev->dev.parent = &platform_bus; > > - pdev->dev.bus = &platform_bus_type; > + if (!pdev->dev.bus) > + pdev->dev.bus = &platform_bus_type; > > if (pdev->id != -1) > dev_set_name(&pdev->dev, "%s.%d", pdev->name, pdev->id); > @@ -482,7 +483,8 @@ static void platform_drv_shutdown(struct device *_dev) > */ > int platform_driver_register(struct platform_driver *drv) > { > - drv->driver.bus = &platform_bus_type; > + if (!drv->driver.bus) > + drv->driver.bus = &platform_bus_type; > if (drv->probe) > drv->driver.probe = platform_drv_probe; > if (drv->remove) > @@ -539,12 +541,12 @@ int __init_or_module platform_driver_probe(struct platform_driver *drv, > * if the probe was successful, and make sure any forced probes of > * new devices fail. > */ > - spin_lock(&platform_bus_type.p->klist_drivers.k_lock); > + spin_lock(&drv->driver.bus->p->klist_drivers.k_lock); > drv->probe = NULL; > if (code == 0 && list_empty(&drv->driver.p->klist_devices.k_list)) > retval = -ENODEV; > drv->driver.probe = platform_drv_probe_fail; > - spin_unlock(&platform_bus_type.p->klist_drivers.k_lock); > + spin_unlock(&drv->driver.bus->p->klist_drivers.k_lock); > > if (code != retval) > platform_driver_unregister(drv); > @@ -1017,6 +1019,26 @@ struct bus_type platform_bus_type = { > }; > EXPORT_SYMBOL_GPL(platform_bus_type); > > +/** platform_bus_type_init - fill in a pseudo-platform-bus > + * @bus: foriegn bus type > + * > + * This init is basically a selective memcpy that > + * won't overwrite any user-defined attributes and > + * only copies things that platform bus defines anyway > + */ > +void platform_bus_type_init(struct bus_type *bus) > +{ > + if (!bus->dev_attrs) > + bus->dev_attrs = platform_bus_type.dev_attrs; > + if (!bus->match) > + bus->match = platform_bus_type.match; > + if (!bus->uevent) > + bus->uevent = platform_bus_type.uevent; > + if (!bus->pm) > + bus->pm = platform_bus_type.pm; > +} > +EXPORT_SYMBOL_GPL(platform_bus_type_init); > + > int __init platform_bus_init(void) > { > int error; > diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h > index 5417944..fa8c35a 100644 > --- a/include/linux/platform_device.h > +++ b/include/linux/platform_device.h > @@ -79,6 +79,8 @@ extern int platform_driver_probe(struct platform_driver *driver, > #define platform_get_drvdata(_dev) dev_get_drvdata(&(_dev)->dev) > #define platform_set_drvdata(_dev,data) dev_set_drvdata(&(_dev)->dev, (data)) > > +extern void platform_bus_type_init(struct bus_type *); > + > extern struct platform_device *platform_create_bundle(struct platform_driver *driver, > int (*probe)(struct platform_device *), > struct resource *res, unsigned int n_res, -- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
