From: gregkh@linuxfoundation•org (Greg Kroah-Hartman)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] driver core / PM: Add callbacks for PM domain initialization/cleanup
Date: Thu, 19 Mar 2015 14:29:07 +0100 [thread overview]
Message-ID: <20150319132907.GA3707@kroah.com> (raw)
In-Reply-To: <2317791.ICLpdqLgyu@vostro.rjw.lan>
On Wed, Mar 18, 2015 at 04:02:11PM +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel•com>
>
> If PM domains are in use, it may be necessary to prepare the code
> handling a PM domain for driver probing. For example, in some
> cases device drivers rely on the ability to power on the devices
> with the help of the IO runtime PM framework and the PM domain
> code needs to be ready for that. Also, if that code has not been
> fully initialized yet, the driver probing should be deferred.
>
> Moreover, after the probing is complete, it may be necessary to
> put the PM domain in question into the state reflecting the current
> needs of the devices in it, for example, to prevent power from being
> drawn in vain.
>
> For these reasons, introduce new PM domain callbacks, ->activate
> and ->sync, called, respectively, before probing for a device
> driver and after the probing has been completed.
>
> That is not sufficient, however, because the device's PM domain
> pointer has to be populated for the ->activate callback to be
> executed, so setting it in bus type ->probe callback routines
> would be too late. Also, there are bus types where PM domains
> are not used at all and the core should not attempt to set the
> pm_domain pointer for the devices on those buses.
>
> To overcome that difficulty, introduce two new bus type
> callbacks, ->init and ->release, called by bus_add_device() and
> bus_remove_device(), respectively. That will allow ->init to
> be used to populate the pm_domain pointer for the bus types
> that want to do that and ->release will be useful for any
> cleanup that may be necessary after removing a device that
> was part of a PM domain.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel•com>
> ---
>
> It occured to me that we might want to ->sync regardless of whether or
> not the probing had been succenssful, so I changed the code in
> really_probe() along these lines. Please let me know if that's
> not OK.
>
> ---
> drivers/base/bus.c | 12 +++++++++++-
> drivers/base/dd.c | 20 ++++++++++++++------
> include/linux/device.h | 5 +++++
> include/linux/pm.h | 6 ++++++
> 4 files changed, 36 insertions(+), 7 deletions(-)
>
> Index: linux-pm/drivers/base/bus.c
> ===================================================================
> --- linux-pm.orig/drivers/base/bus.c
> +++ linux-pm/drivers/base/bus.c
> @@ -509,10 +509,15 @@ int bus_add_device(struct device *dev)
> int error = 0;
>
> if (bus) {
> + if (bus->init) {
> + error = bus->init(dev);
> + if (error)
> + goto out_put;
> + }
This doesn't make sense to me. A bus just called bus_add_device, it can
do whatever it wanted to right before calling this function, no need for
another callback.
> pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
> error = device_add_attrs(bus, dev);
> if (error)
> - goto out_put;
> + goto out_release;
> error = device_add_groups(dev, bus->dev_groups);
> if (error)
> goto out_groups;
> @@ -534,6 +539,9 @@ out_groups:
> device_remove_groups(dev, bus->dev_groups);
> out_id:
> device_remove_attrs(bus, dev);
> +out_release:
> + if (bus->release)
> + bus->release(dev);
> out_put:
> bus_put(dev->bus);
> return error;
> @@ -597,6 +605,8 @@ void bus_remove_device(struct device *de
> device_remove_groups(dev, dev->bus->dev_groups);
> if (klist_node_attached(&dev->p->knode_bus))
> klist_del(&dev->p->knode_bus);
> + if (bus->release)
> + bus->release(dev);
Same with release(), this happens when a bus wants to remove a device,
it controls this, why have a callback right away? These both shouldn't
be needed.
sorry if I missed this before, I hadn't noticed these callbacks in
previous patches but I wasn't paying much attention.
thanks,
greg k-h
next prev parent reply other threads:[~2015-03-19 13:29 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-13 15:43 [PATCH 0/9] PM / Domains: Don't leave unused PM domains powered after ->probe() Ulf Hansson
2015-03-13 15:43 ` [PATCH 1/9] PM / Domains: Add dev_pm_domain_get|put() APIs Ulf Hansson
2015-03-14 1:31 ` Rafael J. Wysocki
2015-03-16 9:26 ` Ulf Hansson
2015-03-17 3:01 ` Rafael J. Wysocki
2015-03-17 9:27 ` Ulf Hansson
2015-03-17 14:45 ` Rafael J. Wysocki
2015-03-17 14:25 ` Russell King - ARM Linux
2015-03-18 1:16 ` Rafael J. Wysocki
2015-03-17 14:40 ` Ulf Hansson
2015-03-18 1:09 ` Rafael J. Wysocki
2015-03-18 13:41 ` Ulf Hansson
2015-03-18 15:02 ` [PATCH] driver core / PM: Add callbacks for PM domain initialization/cleanup Rafael J. Wysocki
2015-03-19 8:49 ` Ulf Hansson
2015-03-19 11:45 ` Rafael J. Wysocki
2015-03-19 13:16 ` Ulf Hansson
2015-03-19 13:29 ` Greg Kroah-Hartman [this message]
2015-03-19 14:21 ` Rafael J. Wysocki
2015-03-19 14:12 ` Greg Kroah-Hartman
2015-03-19 15:24 ` Rafael J. Wysocki
2015-03-19 14:20 ` Alan Stern
2015-03-19 14:45 ` Ulf Hansson
2015-03-19 15:44 ` Rafael J. Wysocki
2015-03-19 15:37 ` Ulf Hansson
2015-03-19 16:04 ` Rafael J. Wysocki
2015-03-19 15:48 ` Ulf Hansson
2015-03-19 16:18 ` Rafael J. Wysocki
2015-03-19 16:58 ` [PATCH] driver core / PM: Add PM domain callbacks for device setup/cleanup Rafael J. Wysocki
2015-03-19 21:51 ` [PATCH v2] " Rafael J. Wysocki
2015-03-19 22:42 ` Dmitry Torokhov
2015-03-20 0:43 ` Rafael J. Wysocki
2015-03-20 0:43 ` Dmitry Torokhov
2015-03-20 7:45 ` Ulf Hansson
2015-03-20 11:37 ` Ulf Hansson
2015-03-20 12:31 ` Rafael J. Wysocki
2015-03-20 12:57 ` [PATCH v3] " Rafael J. Wysocki
2015-03-20 12:59 ` Rafael J. Wysocki
2015-03-20 13:44 ` Ulf Hansson
2015-03-21 0:09 ` Kevin Hilman
2015-03-21 1:00 ` Rafael J. Wysocki
2015-03-22 11:46 ` Greg Kroah-Hartman
2015-03-19 14:46 ` [PATCH] driver core / PM: Add callbacks for PM domain initialization/cleanup Geert Uytterhoeven
2015-03-18 15:09 ` [PATCH 1/9] PM / Domains: Add dev_pm_domain_get|put() APIs Rafael J. Wysocki
2015-03-13 15:43 ` [PATCH 2/9] PM / Domains: Enable genpd to support ->get|put() callbacks Ulf Hansson
2015-03-16 2:11 ` Chao
2015-03-13 15:43 ` [PATCH 3/9] amba: Keep PM domain powered during ->probe() Ulf Hansson
2015-03-13 16:03 ` Russell King - ARM Linux
2015-03-16 8:37 ` Ulf Hansson
2015-03-13 15:43 ` [PATCH 4/9] drivercore / platform: " Ulf Hansson
2015-03-13 15:43 ` [PATCH 5/9] i2c: core: " Ulf Hansson
2015-03-13 15:43 ` [PATCH 6/9] spi: " Ulf Hansson
2015-03-13 15:43 ` [PATCH 7/9] mmc: core: Attach PM domain prior probing of SDIO func driver Ulf Hansson
2015-03-17 5:04 ` Aaron Lu
2015-03-13 15:43 ` [PATCH 8/9] mmmc: core: Keep PM domain powered during ->probe() " Ulf Hansson
2015-03-13 16:10 ` Russell King - ARM Linux
2015-03-16 8:24 ` Ulf Hansson
2015-03-13 15:43 ` [PATCH 9/9] Revert "PM / Domains: Power on the PM domain right after attach completes" Ulf Hansson
2015-03-16 9:07 ` Geert Uytterhoeven
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