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@xxxxxxxxx> --- 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@xxxxxxxxxxxxxxxx https://lists.linaro.org/mailman/listinfo/greybus-dev
