On 5/26/20 1:33 AM, Greg Kroah-Hartman wrote:
On Mon, May 25, 2020 at 06:26:01PM +0000, Krzysztof Wilczyński wrote:
Add driver_to_pm() helper allowing for accessing the Power Management callbacs for a particular device. Access to the callbacs (struct dev_pm_ops) is normally done through using the pm pointer that is embedded within the device_driver struct.
Helper allows for the code required to reference the pm pointer and access Power Management callbas to be simplified. Changing the following:
struct device_driver *drv = dev->driver; if (dev->driver && dev->driver->pm && dev->driver->pm->prepare) { int ret = dev->driver->pm->prepare(dev);
To:
const struct dev_pm_ops *pm = driver_to_pm(dev->driver); if (pm && pm->prepare) { int ret = pm->prepare(dev);
Or, changing the following:
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;To: const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
Signed-off-by: Krzysztof Wilczyński kw@linux.com
include/linux/device/driver.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/include/linux/device/driver.h b/include/linux/device/driver.h index ee7ba5b5417e..ccd0b315fd93 100644 --- a/include/linux/device/driver.h +++ b/include/linux/device/driver.h @@ -236,6 +236,21 @@ driver_find_device_by_acpi_dev(struct device_driver *drv, const void *adev) } #endif +/**
- driver_to_pm - Return Power Management callbacs (struct dev_pm_ops) for
a particular device.
- @drv: Pointer to a device (struct device_driver) for which you want to access
the Power Management callbacks.
- Returns a pointer to the struct dev_pm_ops embedded within the device (struct
- device_driver), or returns NULL if Power Management is not present and the
- pointer is not valid.
- */
+static inline const struct dev_pm_ops *driver_to_pm(struct device_driver *drv) +{
- return drv && drv->pm ? drv->pm : NULL;
This could just be:
if (drv) return drv->pm;
return NULL;
Or if you want to evoke passion in Greg:
return drv ? drv->pm : NULL;
-Alex
I hate ? : lines with a passion, as they break normal pattern mattching in my brain. Please just spell this all out: if (drv && drv->pm) return drv->pm; return NULL;
Much easier to read, and the compiler will do the exact same thing.
Only place ? : are ok to use in my opinion, are as function arguments.
thanks,
greg k-h _______________________________________________ greybus-dev mailing list greybus-dev@lists.linaro.org https://lists.linaro.org/mailman/listinfo/greybus-dev