On Thu, Sep 24, 2015 at 7:02 PM, Thierry Reding <thierry.reding@xxxxxxxxx> wrote: > From: Thierry Reding <treding@xxxxxxxxxx> > > Some modules register several sub-drivers. Provide a helper that makes > it easy to register and unregister a list of sub-drivers, as well as > unwind properly on error. > > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > Signed-off-by: Thierry Reding <treding@xxxxxxxxxx> I raised this already on irc but let's do it here too for the record: Eric Anholt has a very similar thing (but in drm only) with the addition of also integrating with the component framework: http://lists.freedesktop.org/archives/dri-devel/2015-September/090449.html Having something that works for everyone (so includes msm and can be used for vc4 too) would be great. Adding Eric. -Daniel > --- > Documentation/driver-model/platform.txt | 11 ++++++ > drivers/base/platform.c | 60 +++++++++++++++++++++++++++++++++ > include/linux/platform_device.h | 5 +++ > 3 files changed, 76 insertions(+) > > diff --git a/Documentation/driver-model/platform.txt b/Documentation/driver-model/platform.txt > index 07795ec51cde..e80468738ba9 100644 > --- a/Documentation/driver-model/platform.txt > +++ b/Documentation/driver-model/platform.txt > @@ -63,6 +63,17 @@ runtime memory footprint: > int platform_driver_probe(struct platform_driver *drv, > int (*probe)(struct platform_device *)) > > +Kernel modules can be composed of several platform drivers. The platform core > +provides helpers to register and unregister an array of drivers: > + > + int platform_register_drivers(struct platform_driver * const *drivers, > + unsigned int count); > + void platform_unregister_drivers(struct platform_driver * const *drivers, > + unsigned int count); > + > +If one of the drivers fails to register, all drivers registered up to that > +point will be unregistered in reverse order. > + > > Device Enumeration > ~~~~~~~~~~~~~~~~~~ > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index f80aaaf9f610..b7d7987fda97 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -711,6 +711,66 @@ err_out: > } > EXPORT_SYMBOL_GPL(__platform_create_bundle); > > +/** > + * platform_register_drivers - register an array of platform drivers > + * @drivers: an array of drivers to register > + * @count: the number of drivers to register > + * > + * Registers platform drivers specified by an array. On failure to register a > + * driver, all previously registered drivers will be unregistered. Callers of > + * this API should use platform_unregister_drivers() to unregister drivers in > + * the reverse order. > + * > + * Returns: 0 on success or a negative error code on failure. > + */ > +int platform_register_drivers(struct platform_driver * const *drivers, > + unsigned int count) > +{ > + unsigned int i; > + int err; > + > + for (i = 0; i < count; i++) { > + pr_debug("registering platform driver %ps\n", drivers[i]); > + > + err = platform_driver_register(drivers[i]); > + if (err < 0) { > + pr_err("failed to register platform driver %ps: %d\n", > + drivers[i], err); > + goto error; > + } > + } > + > + return 0; > + > +error: > + while (i--) { > + pr_debug("unregistering platform driver %ps\n", drivers[i]); > + platform_driver_unregister(drivers[i]); > + } > + > + return err; > +} > +EXPORT_SYMBOL_GPL(platform_register_drivers); > + > +/** > + * platform_unregister_drivers - unregister an array of platform drivers > + * @drivers: an array of drivers to unregister > + * @count: the number of drivers to unregister > + * > + * Unegisters platform drivers specified by an array. This is typically used > + * to complement an earlier call to platform_register_drivers(). Drivers are > + * unregistered in the reverse order in which they were registered. > + */ > +void platform_unregister_drivers(struct platform_driver * const *drivers, > + unsigned int count) > +{ > + while (count--) { > + pr_debug("unregistering platform driver %ps\n", drivers[count]); > + platform_driver_unregister(drivers[count]); > + } > +} > +EXPORT_SYMBOL_GPL(platform_unregister_drivers); > + > /* modalias support enables more hands-off userspace setup: > * (a) environment variable lets new-style hotplug events work once system is > * fully running: "modprobe $MODALIAS" > diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h > index bba08f44cc97..0c9f16bfdd99 100644 > --- a/include/linux/platform_device.h > +++ b/include/linux/platform_device.h > @@ -270,6 +270,11 @@ extern struct platform_device *__platform_create_bundle( > struct resource *res, unsigned int n_res, > const void *data, size_t size, struct module *module); > > +int platform_register_drivers(struct platform_driver * const *drivers, > + unsigned int count); > +void platform_unregister_drivers(struct platform_driver * const *drivers, > + unsigned int count); > + > /* early platform driver interface */ > struct early_platform_driver { > const char *class_str; > -- > 2.5.0 > > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
