fbdev: nvidia: use generic power management

Drivers should do only device-specific jobs. But in general, drivers using
legacy PCI PM framework for .suspend()/.resume() have to manage many PCI
PM-related tasks themselves which can be done by PCI Core itself. This
brings extra load on the driver and it directly calls PCI helper functions
to handle them.

Switch to the new generic framework by updating function signatures and
define a "struct dev_pm_ops" variable to bind PM callbacks. Also, remove
unnecessary calls to the PCI Helper functions along with the legacy
.suspend & .resume bindings.

Now,
- nvidiafb_suspend() had a "pm_message_t" type parameter as per legacy
  PCI PM framework that got deprecated in generic.
- Rename the callback as nvidiafb_suspend_late() and preserve the
  parameter.
- Define 3 new callbacks as:
        * nvidiafb_suspend()
        * nvidiafb_freeze()
        * nvidiafb_hibernate()
  which in turn call nvidiafb_suspend_late() by passing appropriate value
  for "pm_message_t" type parameter.
- Bind the callbacks in "struct dev_pm_ops" type variable
  "nvidiafb_pm_ops".
Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Bjorn Helgaas <bjorn@helgaas.com>
Cc: Vaibhav Gupta <vaibhav.varodek@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Andres Salomon <dilinger@queued.net>
CC: Antonino Daplas <adaplas@gmail.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200819185654.151170-7-vaibhavgupta40@gmail.com

drivers/video/fbdev/nvidia/nvidia.c

@@ -1037,10 +1037,9 @@ static struct fb_ops nvidia_fb_ops = {
 	.fb_sync        = nvidiafb_sync,
 };
 
-#ifdef CONFIG_PM
-static int nvidiafb_suspend(struct pci_dev *dev, pm_message_t mesg)
+static int nvidiafb_suspend_late(struct device *dev, pm_message_t mesg)
 {
-	struct fb_info *info = pci_get_drvdata(dev);
+	struct fb_info *info = dev_get_drvdata(dev);
 	struct nvidia_par *par = info->par;
 
 	if (mesg.event == PM_EVENT_PRETHAW)
@@ -1052,46 +1051,54 @@ static int nvidiafb_suspend(struct pci_dev *dev, pm_message_t mesg)
 		fb_set_suspend(info, 1);
 		nvidiafb_blank(FB_BLANK_POWERDOWN, info);
 		nvidia_write_regs(par, &par->SavedReg);
-		pci_save_state(dev);
-		pci_disable_device(dev);
-		pci_set_power_state(dev, pci_choose_state(dev, mesg));
 	}
-	dev->dev.power.power_state = mesg;
+	dev->power.power_state = mesg;
 
 	console_unlock();
 	return 0;
 }
 
-static int nvidiafb_resume(struct pci_dev *dev)
+static int __maybe_unused nvidiafb_suspend(struct device *dev)
 {
-	struct fb_info *info = pci_get_drvdata(dev);
-	struct nvidia_par *par = info->par;
+	return nvidiafb_suspend_late(dev, PMSG_SUSPEND);
+}
 
-	console_lock();
-	pci_set_power_state(dev, PCI_D0);
+static int __maybe_unused nvidiafb_hibernate(struct device *dev)
+{
+	return nvidiafb_suspend_late(dev, PMSG_HIBERNATE);
+}
 
-	if (par->pm_state != PM_EVENT_FREEZE) {
-		pci_restore_state(dev);
+static int __maybe_unused nvidiafb_freeze(struct device *dev)
+{
+	return nvidiafb_suspend_late(dev, PMSG_FREEZE);
+}
 
-		if (pci_enable_device(dev))
-			goto fail;
+static int __maybe_unused nvidiafb_resume(struct device *dev)
+{
+	struct fb_info *info = dev_get_drvdata(dev);
+	struct nvidia_par *par = info->par;
 
-		pci_set_master(dev);
-	}
+	console_lock();
 
 	par->pm_state = PM_EVENT_ON;
 	nvidiafb_set_par(info);
 	fb_set_suspend (info, 0);
 	nvidiafb_blank(FB_BLANK_UNBLANK, info);
 
-fail:
 	console_unlock();
 	return 0;
 }
-#else
-#define nvidiafb_suspend NULL
-#define nvidiafb_resume NULL
-#endif
+
+static const struct dev_pm_ops nvidiafb_pm_ops = {
+#ifdef CONFIG_PM_SLEEP
+	.suspend	= nvidiafb_suspend,
+	.resume		= nvidiafb_resume,
+	.freeze		= nvidiafb_freeze,
+	.thaw		= nvidiafb_resume,
+	.poweroff	= nvidiafb_hibernate,
+	.restore	= nvidiafb_resume,
+#endif /* CONFIG_PM_SLEEP */
+};
 
 static int nvidia_set_fbinfo(struct fb_info *info)
 {
@@ -1492,12 +1499,11 @@ static int nvidiafb_setup(char *options)
 #endif				/* !MODULE */
 
 static struct pci_driver nvidiafb_driver = {
-	.name = "nvidiafb",
-	.id_table = nvidiafb_pci_tbl,
-	.probe    = nvidiafb_probe,
-	.suspend  = nvidiafb_suspend,
-	.resume   = nvidiafb_resume,
-	.remove   = nvidiafb_remove,
+	.name      = "nvidiafb",
+	.id_table  = nvidiafb_pci_tbl,
+	.probe     = nvidiafb_probe,
+	.driver.pm = &nvidiafb_pm_ops,
+	.remove    = nvidiafb_remove,
 };
 
 /* ------------------------------------------------------------------------- *