Messages in this thread | | | Date | Mon, 02 Sep 2013 12:25:35 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH v2 0/9] Introduce hwmon_device_register_with_groups and |
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On 08/31/2013 07:48 PM, Guenter Roeck wrote: > This patch series introduces new hwmon API functions > hwmon_device_register_with_groups() and devm_hwmon_device_register_with_groups(). > > hwmon_device_register_with_groups() lets callers register hwmon devices > as well as associated sysfs attributes with a single call. This simplifies > hwmon device registration and avoids potential race conditions seen > if sysfs attributes are created after the initial hwmon device was > registered. > > devm_hwmon_device_register_with_groups() is the managed version of the same > function. > Jean, any comments on this patch series ?
If you are ok with it, I would like to push the new API (patches 1 and 7 of the series) into 3.12, and keep the rest for 3.13.
Thanks, Guenter
> The rationale for the new API is that sysfs attributes should be created > synchronously with device creation to avoid race conditions, as outlined in > http://www.linuxfoundation.org/news-media/blogs/browse/2013/06/how-create-sysfs-file-correctly. > > The first patch of the series introduces hwmon_device_register_with_groups(). > > Patches 2 to 6 convert some hwmon drivers to use the new API to show and > test its use. Only the ds1621 and nct6775 patches have been tested at this time; > the others are informational to show the potential of the new functions. > > Patch 7 introduces devm_hwmon_device_register_with_groups() and > the matching function devm_hwmon_device_unregister(). Patch 8 and 9 > convert the nct6775 and ds1621 drivers drivers to use this function. > > hwmon attributes > > The old hwmon API attaches hwmon attributes to the parent device, not to the > hwmon device itself. With the new API, hwmon attributes are attached to the > hwmon device itself. > > Handling the 'name' attribute for hwmon drivers > > Since sysfs attributes are no longer attached to the parent device, the > mandatory 'name' attribute has to be created explicitly. For some drivers, > this was already the case. I2c drivers, however, create the 'name' attribute > in the i2c core, and it was used by the hwmon driver. > > To simplify name attribute handling, the value of the 'name' attribute is > passed as parameter to hwmon_device_register_with_groups(). The hwmon core > creates and manages the attribute. If a NULL pointer is passed instead of > a name, the attribute is not created. > > Unfortunately, since we need a variable to store the pointer to 'name', > it was necessary to create an internal 'struct hwmon_device'. For this > reason, device_create(), or rather device_create_with_groups() can no > longer be used to create the actual device. device_register() is used > instead, and the device data structures are managed locally. > [ If there is a better solution for this problem, I am listening. ] > > The series is based on my hwmon-next branch and should apply to the top of > linux-next. > > --------- > > v2: Rename API functions > device_create_groups -> device_create_with_groups > hwmon_device_register_groups -> hwmon_device_register_with_groups > Additional parameter 'void *drvdata' for hwmon_device_register_groups. > Additional parameter 'name' for hwmon_device_register_groups. > Introduce devm_hwmon_device_register_with_groups(). > Various fixes in hwmon driver conversions. > >
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