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From:   Vaibhav Gupta <vaibhavgupta40@gmail.com>
To:     Bjorn Helgaas <helgaas@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Bjorn Helgaas <bjorn@helgaas.com>,
        Vaibhav Gupta <vaibhav.varodek@gmail.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Paul Mackerras <paulus@samba.org>,
        Russell King <linux@armlinux.org.uk>,
        Andres Salomon <dilinger@queued.net>,
        Antonino Daplas <adaplas@gmail.com>,
        Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc:     Vaibhav Gupta <vaibhavgupta40@gmail.com>,
        dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-geode@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-kernel-mentees@lists.linuxfoundation.org,
        Shuah Khan <skhan@linuxfoundation.org>
Subject: [PATCH v1 03/12] fbdev: via-core: use generic power management
Date:   Wed,  5 Aug 2020 23:37:13 +0530
Message-Id: <20200805180722.244008-4-vaibhavgupta40@gmail.com>
In-Reply-To: <20200805180722.244008-1-vaibhavgupta40@gmail.com>
References: <20200805180722.244008-1-vaibhavgupta40@gmail.com>
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Drivers using legacy power management .suspen()/.resume() callbacks
have to manage PCI states and device's PM states themselves. They also
need to take care of standard configuration registers.

Switch to generic power management framework using a single
"struct dev_pm_ops" variable to take the unnecessary load from the driver.
This also avoids the need for the driver to directly call most of the PCI
helper functions and device power state control functions, as through
the generic framework PCI Core takes care of the necessary operations,
and drivers are required to do only device-specific jobs.

Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
---
 drivers/video/fbdev/via/via-core.c | 39 ++++++++++++------------------
 include/linux/via-core.h           |  2 --
 2 files changed, 16 insertions(+), 25 deletions(-)

diff --git a/drivers/video/fbdev/via/via-core.c b/drivers/video/fbdev/via/via-core.c
index 703ddee9a244..89d75079b730 100644
--- a/drivers/video/fbdev/via/via-core.c
+++ b/drivers/video/fbdev/via/via-core.c
@@ -558,9 +558,8 @@ static void via_teardown_subdevs(void)
 /*
  * Power management functions
  */
-#ifdef CONFIG_PM
-static LIST_HEAD(viafb_pm_hooks);
-static DEFINE_MUTEX(viafb_pm_hooks_lock);
+static __maybe_unused LIST_HEAD(viafb_pm_hooks);
+static __maybe_unused DEFINE_MUTEX(viafb_pm_hooks_lock);
 
 void viafb_pm_register(struct viafb_pm_hooks *hooks)
 {
@@ -580,12 +579,10 @@ void viafb_pm_unregister(struct viafb_pm_hooks *hooks)
 }
 EXPORT_SYMBOL_GPL(viafb_pm_unregister);
 
-static int via_suspend(struct pci_dev *pdev, pm_message_t state)
+static int __maybe_unused via_suspend(struct device *dev)
 {
 	struct viafb_pm_hooks *hooks;
 
-	if (state.event != PM_EVENT_SUSPEND)
-		return 0;
 	/*
 	 * "I've occasionally hit a few drivers that caused suspend
 	 * failures, and each and every time it was a driver bug, and
@@ -600,24 +597,13 @@ static int via_suspend(struct pci_dev *pdev, pm_message_t state)
 		hooks->suspend(hooks->private);
 	mutex_unlock(&viafb_pm_hooks_lock);
 
-	pci_save_state(pdev);
-	pci_disable_device(pdev);
-	pci_set_power_state(pdev, pci_choose_state(pdev, state));
 	return 0;
 }
 
-static int via_resume(struct pci_dev *pdev)
+static int __maybe_unused via_resume(struct device *dev)
 {
 	struct viafb_pm_hooks *hooks;
 
-	/* Get the bus side powered up */
-	pci_set_power_state(pdev, PCI_D0);
-	pci_restore_state(pdev);
-	if (pci_enable_device(pdev))
-		return 0;
-
-	pci_set_master(pdev);
-
 	/* Now bring back any subdevs */
 	mutex_lock(&viafb_pm_hooks_lock);
 	list_for_each_entry(hooks, &viafb_pm_hooks, list)
@@ -626,7 +612,6 @@ static int via_resume(struct pci_dev *pdev)
 
 	return 0;
 }
-#endif /* CONFIG_PM */
 
 static int via_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
@@ -712,15 +697,23 @@ static const struct pci_device_id via_pci_table[] = {
 };
 MODULE_DEVICE_TABLE(pci, via_pci_table);
 
+static const struct dev_pm_ops via_pm_ops = {
+#ifdef CONFIG_PM_SLEEP
+	.suspend	= via_suspend,
+	.resume		= via_resume,
+	.freeze		= NULL,
+	.thaw		= via_resume,
+	.poweroff	= NULL,
+	.restore	= via_resume,
+#endif
+};
+
 static struct pci_driver via_driver = {
 	.name		= "viafb",
 	.id_table	= via_pci_table,
 	.probe		= via_pci_probe,
 	.remove		= via_pci_remove,
-#ifdef CONFIG_PM
-	.suspend	= via_suspend,
-	.resume		= via_resume,
-#endif
+	.driver.pm	= &via_pm_ops,
 };
 
 static int __init via_core_init(void)
diff --git a/include/linux/via-core.h b/include/linux/via-core.h
index 9e802deedb2d..8737599b9148 100644
--- a/include/linux/via-core.h
+++ b/include/linux/via-core.h
@@ -47,7 +47,6 @@ struct via_port_cfg {
 /*
  * Allow subdevs to register suspend/resume hooks.
  */
-#ifdef CONFIG_PM
 struct viafb_pm_hooks {
 	struct list_head list;
 	int (*suspend)(void *private);
@@ -57,7 +56,6 @@ struct viafb_pm_hooks {
 
 void viafb_pm_register(struct viafb_pm_hooks *hooks);
 void viafb_pm_unregister(struct viafb_pm_hooks *hooks);
-#endif /* CONFIG_PM */
 
 /*
  * This is the global viafb "device" containing stuff needed by
-- 
2.27.0