From: Jon Hunter <jonathanh@nvidia.com>
To: Ulf Hansson <ulf.hansson@linaro.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
<linux-pm@vger.kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Todor Tomov <todor.tomov@linaro.org>,
"Rajendra Nayak" <rnayak@codeaurora.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Kevin Hilman <khilman@kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
<linux-tegra@vger.kernel.org>
Subject: Re: [PATCH 9/9] PM / Domains: Add dev_pm_domain_attach_by_id() to manage multi PM domains
Date: Thu, 24 May 2018 16:48:53 +0100 [thread overview]
Message-ID: <1c21d18e-954a-f3a8-9817-0117b7cb7e4f@nvidia.com> (raw)
In-Reply-To: <1526639490-12167-10-git-send-email-ulf.hansson@linaro.org>
On 18/05/18 11:31, Ulf Hansson wrote:
> The existing dev_pm_domain_attach() function, allows a single PM domain to
> be attached per device. To be able to support devices that are partitioned
> across multiple PM domains, let's introduce a new interface,
> dev_pm_domain_attach_by_id().
>
> The dev_pm_domain_attach_by_id() returns a new allocated struct device with
> the corresponding attached PM domain. This enables for example a driver to
> operate on the new device from a power management point of view. The driver
> may then also benefit from using the received device, to set up so called
> device-links towards its original device. Depending on the situation, these
> links may then be dynamically changed.
>
> The new interface is typically called by drivers during their probe phase,
> in case they manages devices which uses multiple PM domains. If that is the
> case, the driver also becomes responsible of managing the detaching of the
> PM domains, which typically should be done at the remove phase. Detaching
> is done by calling the existing dev_pm_domain_detach() function and for
> each of the received devices from dev_pm_domain_attach_by_id().
>
> Note, currently its only genpd that supports multiple PM domains per
> device, but dev_pm_domain_attach_by_id() can easily by extended to cover
> other PM domain types, if/when needed.
>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
> drivers/base/power/common.c | 33 ++++++++++++++++++++++++++++++++-
> include/linux/pm_domain.h | 7 +++++++
> 2 files changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
> index 7ae62b6..d3db974 100644
> --- a/drivers/base/power/common.c
> +++ b/drivers/base/power/common.c
> @@ -117,13 +117,44 @@ int dev_pm_domain_attach(struct device *dev, bool power_on)
> EXPORT_SYMBOL_GPL(dev_pm_domain_attach);
>
> /**
> + * dev_pm_domain_attach_by_id - Attach a device to one of its PM domains.
Isn't this more of a 'get'?
> + * @index: The index of the PM domain.
> + * @dev: Device to attach.
Isn't this just the device associated with the PM domain we are getting?
> + *
> + * As @dev may only be attached to a single PM domain, the backend PM domain
> + * provider should create a virtual device to attach instead. As attachment
> + * succeeds, the ->detach() callback in the struct dev_pm_domain should be
> + * assigned by the corresponding backend attach function.
> + *
> + * This function should typically be invoked from drivers during probe phase.
> + * Especially for those that manages devices which requires power management
> + * through more than one PM domain.
> + *
> + * Callers must ensure proper synchronization of this function with power
> + * management callbacks.
> + *
> + * Returns the virtual attached device in case successfully attached PM domain,
> + * NULL in case @dev don't need a PM domain, else a PTR_ERR().
Should this be 'NULL in the case where the @dev already has a power-domain'?
> + */
> +struct device *dev_pm_domain_attach_by_id(struct device *dev,
> + unsigned int index)
> +{
> + if (dev->pm_domain)
I wonder if this is worthy of a ...
if (WARN_ON(dev->pm_domain))
> + return NULL;
Don't we consider this an error case? I wonder why not return PTR_ERR
here as well? This would be consistent with dev_pm_domain_attach().
Cheers
Jon
--
nvpublic
next prev parent reply other threads:[~2018-05-24 15:49 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-18 10:31 [PATCH 0/9] PM / Domains: Add support for multi PM domains per device Ulf Hansson
2018-05-18 10:31 ` [PATCH 1/9] PM / Domains: Drop extern declarations of functions in pm_domain.h Ulf Hansson
2018-05-18 10:31 ` [PATCH 2/9] PM / Domains: Drop __pm_genpd_add_device() Ulf Hansson
2018-05-18 10:31 ` [PATCH 3/9] PM / Domains: Drop genpd as in-param for pm_genpd_remove_device() Ulf Hansson
2018-05-18 10:31 ` [PATCH 4/9] PM / Domains: Drop unused parameter in genpd_allocate_dev_data() Ulf Hansson
2018-05-18 10:31 ` [PATCH 5/9] PM / Domains: dt: Allow power-domain property to be a list of phandles Ulf Hansson
2018-05-18 10:46 ` Geert Uytterhoeven
2018-05-18 10:31 ` [PATCH 6/9] PM / Domains: Don't attach devices in genpd with multi PM domains Ulf Hansson
2018-05-18 10:31 ` [PATCH 7/9] PM / Domains: Split genpd_dev_pm_attach() Ulf Hansson
2018-05-18 10:31 ` [PATCH 8/9] PM / Domains: Add support for multi PM domains per device to genpd Ulf Hansson
2018-05-22 14:31 ` Jon Hunter
2018-05-22 14:47 ` Ulf Hansson
2018-05-22 20:55 ` Jon Hunter
2018-05-23 4:51 ` Rajendra Nayak
2018-05-23 6:12 ` Ulf Hansson
2018-05-23 9:07 ` Jon Hunter
2018-05-23 9:27 ` Rajendra Nayak
2018-05-23 9:33 ` Ulf Hansson
2018-05-23 9:45 ` Jon Hunter
2018-05-23 9:47 ` Ulf Hansson
2018-05-23 10:22 ` Jon Hunter
2018-05-24 7:04 ` Ulf Hansson
2018-05-24 9:36 ` Jon Hunter
2018-05-24 12:17 ` Ulf Hansson
2018-05-24 14:34 ` Jon Hunter
2018-05-24 21:21 ` Ulf Hansson
2018-05-25 8:22 ` Jon Hunter
2018-05-18 10:31 ` [PATCH 9/9] PM / Domains: Add dev_pm_domain_attach_by_id() to manage multi PM domains Ulf Hansson
2018-05-24 15:48 ` Jon Hunter [this message]
2018-05-24 21:11 ` Ulf Hansson
2018-05-25 8:31 ` Jon Hunter
2018-05-25 10:45 ` Ulf Hansson
2018-05-25 11:07 ` Jon Hunter
2018-05-25 12:34 ` Ulf Hansson
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