[Linux-kernel-mentees] [PATCH v1 07/12] fbdev: savagefb: use generic power management

[Vaibhav Gupta <vaibhavgupta40@gmail.com>]

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/savage/savagefb_driver.c | 52 ++++++++++++--------
 1 file changed, 32 insertions(+), 20 deletions(-)

diff --git a/drivers/video/fbdev/savage/savagefb_driver.c b/drivers/video/fbdev/savage/savagefb_driver.c
index 3c8ae87f0ea7..d6aae759e90f 100644
--- a/drivers/video/fbdev/savage/savagefb_driver.c
+++ b/drivers/video/fbdev/savage/savagefb_driver.c
@@ -2346,9 +2346,9 @@ static void savagefb_remove(struct pci_dev *dev)
 	}
 }
 
-static int savagefb_suspend(struct pci_dev *dev, pm_message_t mesg)
+static int savagefb_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 savagefb_par *par = info->par;
 
 	DBG("savagefb_suspend");
@@ -2356,7 +2356,7 @@ static int savagefb_suspend(struct pci_dev *dev, pm_message_t mesg)
 	if (mesg.event == PM_EVENT_PRETHAW)
 		mesg.event = PM_EVENT_FREEZE;
 	par->pm_state = mesg.event;
-	dev->dev.power.power_state = mesg;
+	dev->power.power_state = mesg;
 
 	/*
 	 * For PM_EVENT_FREEZE, do not power down so the console
@@ -2374,17 +2374,29 @@ static int savagefb_suspend(struct pci_dev *dev, pm_message_t mesg)
 	savagefb_blank(FB_BLANK_POWERDOWN, info);
 	savage_set_default_par(par, &par->save);
 	savage_disable_mmio(par);
-	pci_save_state(dev);
-	pci_disable_device(dev);
-	pci_set_power_state(dev, pci_choose_state(dev, mesg));
 	console_unlock();
 
 	return 0;
 }
 
-static int savagefb_resume(struct pci_dev* dev)
+static int __maybe_unused savagefb_suspend(struct device *dev)
 {
-	struct fb_info *info = pci_get_drvdata(dev);
+	return savagefb_suspend_late(dev, PMSG_SUSPEND);
+}
+
+static int __maybe_unused savagefb_hibernate(struct device *dev)
+{
+	return savagefb_suspend_late(dev, PMSG_HIBERNATE);
+}
+
+static int __maybe_unused savagefb_freeze(struct device *dev)
+{
+	return savagefb_suspend_late(dev, PMSG_FREEZE);
+}
+
+static int __maybe_unused savagefb_resume(struct device *dev)
+{
+	struct fb_info *info = dev_get_drvdata(dev);
 	struct savagefb_par *par = info->par;
 	int cur_state = par->pm_state;
 
@@ -2396,20 +2408,11 @@ static int savagefb_resume(struct pci_dev* dev)
 	 * The adapter was not powered down coming back from a
 	 * PM_EVENT_FREEZE.
 	 */
-	if (cur_state == PM_EVENT_FREEZE) {
-		pci_set_power_state(dev, PCI_D0);
+	if (cur_state == PM_EVENT_FREEZE)
 		return 0;
-	}
 
 	console_lock();
 
-	pci_set_power_state(dev, PCI_D0);
-	pci_restore_state(dev);
-
-	if (pci_enable_device(dev))
-		DBG("err");
-
-	pci_set_master(dev);
 	savage_enable_mmio(par);
 	savage_init_hw(par);
 	savagefb_set_par(info);
@@ -2420,6 +2423,16 @@ static int savagefb_resume(struct pci_dev* dev)
 	return 0;
 }
 
+static const struct dev_pm_ops savagefb_pm_ops = {
+#ifdef CONFIG_PM_SLEEP
+	.suspend	= savagefb_suspend,
+	.resume		= savagefb_resume,
+	.freeze		= savagefb_freeze,
+	.thaw		= savagefb_resume,
+	.poweroff	= savagefb_hibernate,
+	.restore	= savagefb_resume,
+#endif
+};
 
 static const struct pci_device_id savagefb_devices[] = {
 	{PCI_VENDOR_ID_S3, PCI_CHIP_SUPSAV_MX128,
@@ -2500,8 +2513,7 @@ static struct pci_driver savagefb_driver = {
 	.name =     "savagefb",
 	.id_table = savagefb_devices,
 	.probe =    savagefb_probe,
-	.suspend =  savagefb_suspend,
-	.resume =   savagefb_resume,
+	.driver.pm = &savagefb_pm_ops,
 	.remove =   savagefb_remove,
 };
 
-- 
2.27.0

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