Messages in this thread Patches in this message | | | Subject | Re: [PATCH 01/12 v2] Platform: add a dev_groups pointer to struct platform_driver | From | Richard Gong <> | Date | Thu, 25 Jul 2019 14:02:03 -0500 |
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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.
My changes are below,
diff --git a/include/linux/device.h b/include/linux/device.h index 6717ade..9207aea3 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -296,6 +296,7 @@ struct device_driver { int (*suspend) (struct device *dev, pm_message_t state); int (*resume) (struct device *dev); const struct attribute_group **groups; + const struct attribute_group **dev_groups;
const struct dev_pm_ops *pm;
diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 994a907..a91e69f 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -554,9 +554,19 @@ static int really_probe(struct device *dev, struct device_driver *drv) goto probe_failed; }
+ if (drv->dev_groups) { + if (device_add_groups(dev, drv->dev_groups)) { + dev_err(dev, "device_add_groups(%s) failed\n", + dev_name(dev)); + goto dev_groups_failed; + } + } + if (test_remove) { test_remove = false;
+ device_remove_groups(dev, drv->dev_groups); + if (dev->bus->remove) dev->bus->remove(dev); else if (drv->remove) @@ -584,6 +594,12 @@ static int really_probe(struct device *dev, struct device_driver *drv) drv->bus->name, __func__, dev_name(dev), drv->name); goto done;
+dev_groups_failed: + if (dev->bus->remove) + dev->bus->remove(dev); + else if (drv->remove) + drv->remove(dev); + probe_failed: if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, @@ -1114,6 +1130,8 @@ static void __device_release_driver(struct device *dev, struct device *parent)
pm_runtime_put_sync(dev);
+ device_remove_groups(dev, drv->dev_groups); + if (dev->bus && dev->bus->remove) dev->bus->remove(dev); else if (drv->remove)
diff --git a/drivers/firmware/stratix10-rsu.c b/drivers/firmware/stratix10-rsu.c index 98d8030..93b44e9 100644 --- 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, }, };
Regards, Richard
>> diff --git a/drivers/base/dd.c b/drivers/base/dd.c >> index 0df9b4461766..61d9d650d890 100644 >> --- a/drivers/base/dd.c >> +++ b/drivers/base/dd.c >> @@ -515,9 +515,17 @@ static int really_probe(struct device *dev, struct device_driver *drv) >> goto probe_failed; >> } >> >> + if (device_add_groups(dev, drv->dev_groups)) { >> + printk(KERN_ERR "%s: device_add_groups(%s) failed\n", >> + __func__, dev_name(dev)); > > dev_err() of course :) > > thanks for the review, much appreciated. > > greg k-h >
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