Messages in this thread Patch in this message | | | Date | Thu, 25 Jul 2019 21:04:43 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH 01/12 v2] Platform: add a dev_groups pointer to struct platform_driver |
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On Thu, Jul 25, 2019 at 02:02:03PM -0500, Richard Gong wrote: > Hi Greg, > > On 7/25/19 8:44 AM, Greg Kroah-Hartman wrote: > > On Sat, Jul 20, 2019 at 07:38:57AM +0300, Dmitry Torokhov wrote: > > > On Fri, Jul 19, 2019 at 08:52:20PM +0900, Greg Kroah-Hartman wrote: > > > > On Sat, Jul 06, 2019 at 10:39:38AM -0700, Dmitry Torokhov wrote: > > > > > On Sat, Jul 6, 2019 at 10:19 AM Greg Kroah-Hartman > > > > > <gregkh@linuxfoundation.org> wrote: > > > > > > > > > > > > On Sat, Jul 06, 2019 at 10:04:39AM -0700, Dmitry Torokhov wrote: > > > > > > > Hi Greg, > > > > > > > > > > > > > > On Sat, Jul 6, 2019 at 1:32 AM Greg Kroah-Hartman > > > > > > > <gregkh@linuxfoundation.org> wrote: > > > > > > > > > > > > > > > > On Thu, Jul 04, 2019 at 02:17:22PM -0700, Dmitry Torokhov wrote: > > > > > > > > > Hi Greg, > > > > > > > > > > > > > > > > > > On Thu, Jul 4, 2019 at 5:15 AM Greg Kroah-Hartman > > > > > > > > > <gregkh@linuxfoundation.org> wrote: > > > > > > > > > > > > > > > > > > > > Platform drivers like to add sysfs groups to their device, but right now > > > > > > > > > > they have to do it "by hand". The driver core should handle this for > > > > > > > > > > them, but there is no way to get to the bus-default attribute groups as > > > > > > > > > > all platform devices are "special and unique" one-off drivers/devices. > > > > > > > > > > > > > > > > > > > > To combat this, add a dev_groups pointer to platform_driver which allows > > > > > > > > > > a platform driver to set up a list of default attributes that will be > > > > > > > > > > properly created and removed by the platform driver core when a probe() > > > > > > > > > > function is successful and removed right before the device is unbound. > > > > > > > > > > > > > > > > > > Why is this limited to platform bus? Drivers for other buses also > > > > > > > > > often want to augment list of their attributes during probe(). I'd > > > > > > > > > move it to generic probe handling. > > > > > > > > > > > > > > > > This is not limited to the platform at all, the driver core supports > > > > > > > > this for any bus type today, but it's then up to the bus-specific code > > > > > > > > to pass that on to the driver core. That's usually set for the > > > > > > > > bus-specific attributes that they want exposed for all devices of that > > > > > > > > bus type (see the bus_groups, dev_groups, and drv_groups pointers in > > > > > > > > struct bus_type). > > > > > > > > > > > > > > > > For the platform devices, the problem is that this is something that the > > > > > > > > individual drivers want after they bind to the device. And as all > > > > > > > > platform devices are "different" they can't be a "common" set of > > > > > > > > attributes, so they need to be created after the device is bound to the > > > > > > > > driver. > > > > > > > > > > > > > > I believe that your assertion that only platform devices want to > > > > > > > install custom attributes is incorrect. > > > > > > > > > > > > Sorry, I didn't mean to imply that only platform drivers want to do > > > > > > this, as you say, many other drivers do as well. > > > > > > > > > > > > > Drivers for devices attached > > > > > > > to serio, i2c, USB, spi, etc, etc, all have additional attributes: > > > > > > > > > > > > > > dtor@dtor-ws:~/kernel/work (master *)$ grep -l '\(i2c\|usb\|spi\)' > > > > > > > `git grep -l '\(device_add_group\|sysfs_create_group\)' -- drivers` | > > > > > > > wc -l > > > > > > > 170 > > > > > > > > > > > > > > I am pretty sure some of this count is false positives, but majority > > > > > > > is actually proper hits. > > > > > > > > > > > > Yeah, I know, we need to add this type of functionality to those busses > > > > > > as well. I don't see a way of doing it other than this bus-by-bus > > > > > > conversion, do you? > > > > > > > > > > Can't you push the **dev_groups from platform driver down to the > > > > > generic driver structure and handle them in driver_sysfs_add()? > > > > > > > > Sorry for the delay, got busy with the merge window... > > > > > > > > Anyway, no, we can't call this then, because driver_sysfs_add() is > > > > called before probe() is called. So if probe() fails, we don't bind the > > > > device to the driver. We also should not be creating sysfs files for a > > > > driver that has not had probe() called yet, as internal structures will > > > > not be set up at that time. > > > > > > Ah, yes, I got confused by the fact that driver_sysfs_remove is called > > > early. Anyway, I think you want something like this: > > > > Ah, nice, this looks good. Let me try this and see how it goes... > > > > I tried Dmitry's patch on Intel Stratix10 platform and it works. > > I added one minor change on the top of Dmitry's patch, since I think we need > add one additional check prior to device_add_groups(). To align with > Dmitry's patch, I also change my code to use the new dev_groups pointer in > the struct of device_driver.
Thanks for testing!
> My changes are below,
<snip>
> --- a/drivers/firmware/stratix10-rsu.c > +++ b/drivers/firmware/stratix10-rsu.c > @@ -391,9 +391,9 @@ static int stratix10_rsu_remove(struct platform_device > *pdev) > static struct platform_driver stratix10_rsu_driver = { > .probe = stratix10_rsu_probe, > .remove = stratix10_rsu_remove, > .driver = { > .name = "stratix10-rsu", > + .dev_groups = rsu_groups,
I'd prefer to leave the dev_groups in the platform driver code, as no one should have to do this crazy "sub structure definition" that platform drivers seem to love to do.
Here's the patch that I currently have on top of Dmitry's that is getting run through 0-day right now.
I'll resend the whole patch series once it passes (hopefully tomorrow).
thanks,
greg k-h
From 6ad595541f81407f401d992b89ae1269e88cb3be Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Date: Thu, 25 Jul 2019 15:54:24 +0200 Subject: [PATCH 02/13] platform: add a dev_groups pointer to struct platform_driver
As the driver core now provides the ability to directly add/remove device groups when a driver is bound/unbound to a device, just pass that pointer along to the driver core.
This allows us to fix up platform drivers to not need to create/remove groups "by hand" anymore.
Cc: Richard Gong <richard.gong@linux.intel.com> Cc: Romain Izard <romain.izard.pro@gmail.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Mans Rullgard <mans@mansr.com> Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: linux-kernel@vger.kernel.org Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/base/platform.c | 1 + include/linux/platform_device.h | 1 + 2 files changed, 2 insertions(+)
diff --git a/drivers/base/platform.c b/drivers/base/platform.c index 506a0175a5a7..21b3817569cd 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -667,6 +667,7 @@ int __platform_driver_register(struct platform_driver *drv, drv->driver.probe = platform_drv_probe; drv->driver.remove = platform_drv_remove; drv->driver.shutdown = platform_drv_shutdown; + drv->driver.dev_groups = drv->dev_groups; return driver_register(&drv->driver); } diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h index 9bc36b589827..9945a08b872a 100644 --- a/include/linux/platform_device.h +++ b/include/linux/platform_device.h @@ -189,6 +189,7 @@ struct platform_driver { int (*resume)(struct platform_device *); struct device_driver driver; const struct platform_device_id *id_table; + const struct attribute_group **dev_groups; bool prevent_deferred_probe; }; -- 2.22.0
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