From: Alex Elder <elder@linaro.org>
To: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Krzysztof Wilczyński" <kw@linux.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
linux-pci@vger.kernel.org,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Pavel Machek <pavel@ucw.cz>,
linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org,
Kevin Hilman <khilman@kernel.org>,
Julian Wiedmann <jwi@linux.ibm.com>,
linux-acpi@vger.kernel.org, Jakub Kicinski <kuba@kernel.org>,
Dan Carpenter <dan.carpenter@oracle.com>,
Len Brown <lenb@kernel.org>,
linux-pm@vger.kernel.org,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
Ursula Braun <ubraun@linux.ibm.com>,
Johan Hovold <johan@kernel.org>,
greybus-dev@lists.linaro.org,
John Stultz <john.stultz@linaro.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Felipe Balbi <balbi@kernel.org>, Alex Elder <elder@kernel.org>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
netdev@vger.kernel.org, linux-usb@vger.kernel.org,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Karsten Graul <kgraul@linux.ibm.com>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [greybus-dev] [PATCH 1/8] driver core: Add helper for accessing Power Management callbacs
Date: Tue, 26 May 2020 06:53:22 -0500 [thread overview]
Message-ID: <41c42552-0f4f-df6a-d587-5c62333aa6a8@linaro.org> (raw)
In-Reply-To: <20200526063334.GB2578492@kroah.com>
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
>
next prev parent reply other threads:[~2020-05-26 11:53 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-25 18:26 [PATCH 0/8] Add helper for accessing Power Management callbacs Krzysztof Wilczyński
2020-05-25 18:26 ` [PATCH 1/8] driver core: " Krzysztof Wilczyński
2020-05-26 6:33 ` Greg Kroah-Hartman
2020-05-26 11:53 ` Alex Elder [this message]
2020-05-26 15:01 ` [greybus-dev] " Krzysztof Wilczyński
2020-05-25 18:26 ` [PATCH 2/8] ACPI: PM: Use the new device_to_pm() helper to access struct dev_pm_ops Krzysztof Wilczyński
2020-05-26 8:37 ` Rafael J. Wysocki
2020-05-26 9:45 ` Pavel Machek
2020-05-26 10:35 ` Rafael J. Wysocki
2020-05-25 18:26 ` [PATCH 3/8] greybus: " Krzysztof Wilczyński
2020-05-26 11:53 ` [greybus-dev] " Alex Elder
2020-05-25 18:26 ` [PATCH 4/8] scsi: pm: " Krzysztof Wilczyński
2020-05-25 18:26 ` [PATCH 5/8] usb: phy: fsl: " Krzysztof Wilczyński
2020-05-26 8:38 ` Rafael J. Wysocki
2020-05-25 18:26 ` [PATCH 6/8] PCI/PM: " Krzysztof Wilczyński
2020-05-25 18:26 ` [PATCH 7/8] PM: " Krzysztof Wilczyński
2020-05-26 8:33 ` Rafael J. Wysocki
2020-05-25 18:26 ` [PATCH 8/8] net/iucv: " Krzysztof Wilczyński
2020-05-26 6:35 ` Greg Kroah-Hartman
2020-05-26 15:07 ` Krzysztof Wilczyński
2020-05-26 15:19 ` Rafael J. Wysocki
2020-05-26 15:28 ` Alan Stern
2020-05-26 16:06 ` Rafael J. Wysocki
2020-05-26 16:48 ` [greybus-dev] " Alex Elder
2020-05-26 7:07 ` Ursula Braun
2020-05-26 14:57 ` Krzysztof Wilczyński
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