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[158.174.22.67]) by smtp.gmail.com with ESMTPSA id f10sm3869505lff.56.2017.12.20.06.09.31 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 20 Dec 2017 06:09:31 -0800 (PST) From: Ulf Hansson To: Kishon Vijay Abraham I , linux-kernel@vger.kernel.org Cc: "Rafael J . Wysocki" , linux-pm@vger.kernel.org, Yoshihiro Shimoda , Geert Uytterhoeven , linux-renesas-soc@vger.kernel.org, Ulf Hansson , Jonathan Corbet , linux-doc@vger.kernel.org Subject: [PATCH v2 3/3] phy: core: Update the runtime PM section in the docs to reflect changes Date: Wed, 20 Dec 2017 15:09:20 +0100 Message-Id: <1513778960-10073-4-git-send-email-ulf.hansson@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1513778960-10073-1-git-send-email-ulf.hansson@linaro.org> References: <1513778960-10073-1-git-send-email-ulf.hansson@linaro.org> Let's update and clarify he phy documentation, to reflect the latest changes around the runtime PM deployment in the phy core. Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Signed-off-by: Ulf Hansson --- Documentation/phy.txt | 29 ++++++++++++++++------------- 1 file changed, 16 insertions(+), 13 deletions(-) -- 2.7.4 diff --git a/Documentation/phy.txt b/Documentation/phy.txt index 457c3e0..1c2c761 100644 --- a/Documentation/phy.txt +++ b/Documentation/phy.txt @@ -160,19 +160,22 @@ associated with this PHY. PM Runtime ========== -This subsystem is pm runtime enabled. So while creating the PHY, -pm_runtime_enable of the phy device created by this subsystem is called and -while destroying the PHY, pm_runtime_disable is called. Note that the phy -device created by this subsystem will be a child of the device that calls -phy_create (PHY provider device). - -So pm_runtime_get_sync of the phy_device created by this subsystem will invoke -pm_runtime_get_sync of PHY provider device because of parent-child relationship. -It should also be noted that phy_power_on and phy_power_off performs -phy_pm_runtime_get_sync and phy_pm_runtime_put respectively. -There are exported APIs like phy_pm_runtime_get, phy_pm_runtime_get_sync, -phy_pm_runtime_put, phy_pm_runtime_put_sync, phy_pm_runtime_allow and -phy_pm_runtime_forbid for performing PM operations. +This subsystem deploys runtime PM support. More precisely, calls to +pm_runtime_get_sync() and to pm_runtime_put() surrounds calls to the phy +provider callbacks, ->init|exit(), in phy_init|exit(). At phy_power_on(), the +runtime PM usage count is raised again, via pm_runtime_get_sync(). The usage +count remain raised, until the internal phy power on count reaches zero in +phy_power_off(), at which point pm_runtime_put() is called to restore the +runtime PM usage count. In this way, the device is guranteed to stay runtime +resumed as long as the phy is powered on. + +In regards to the runtime PM deployment in the phy core, it should also be +noted that it's deployed for the phy provider device, which is the parent of +the phy child device. In other words, the phy device created by the phy core +remains runtime PM disabled. Of course, whether runtime PM is really used or +not, depends on whether the phy provider driver has enabled runtime PM for its +provider device. More exactly, pm_runtime_enable() needs to be called prior +calling phy_create() or devm_phy_create(). PHY Mappings ============