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

[Vaibhav Gupta]

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 at gmail.com>
---
 drivers/video/fbdev/arkfb.c | 41 +++++++++++++++----------------------
 1 file changed, 17 insertions(+), 24 deletions(-)

diff --git a/drivers/video/fbdev/arkfb.c b/drivers/video/fbdev/arkfb.c
index 11ab9a153860..6a4114db0dfd 100644
--- a/drivers/video/fbdev/arkfb.c
+++ b/drivers/video/fbdev/arkfb.c
@@ -1085,12 +1085,11 @@ static void ark_pci_remove(struct pci_dev *dev)
 }
 
 
-#ifdef CONFIG_PM
 /* PCI suspend */
 
-static int ark_pci_suspend (struct pci_dev* dev, pm_message_t state)
+static int __maybe_unused ark_pci_suspend(struct device *dev)
 {
-	struct fb_info *info = pci_get_drvdata(dev);
+	struct fb_info *info = dev_get_drvdata(dev);
 	struct arkfb_info *par = info->par;
 
 	dev_info(info->device, "suspend\n");
@@ -1098,7 +1097,7 @@ static int ark_pci_suspend (struct pci_dev* dev, pm_message_t state)
 	console_lock();
 	mutex_lock(&(par->open_lock));
 
-	if ((state.event == PM_EVENT_FREEZE) || (par->ref_count == 0)) {
+	if (par->ref_count == 0) {
 		mutex_unlock(&(par->open_lock));
 		console_unlock();
 		return 0;
@@ -1106,10 +1105,6 @@ static int ark_pci_suspend (struct pci_dev* dev, pm_message_t state)
 
 	fb_set_suspend(info, 1);
 
-	pci_save_state(dev);
-	pci_disable_device(dev);
-	pci_set_power_state(dev, pci_choose_state(dev, state));
-
 	mutex_unlock(&(par->open_lock));
 	console_unlock();
 
@@ -1119,9 +1114,9 @@ static int ark_pci_suspend (struct pci_dev* dev, pm_message_t state)
 
 /* PCI resume */
 
-static int ark_pci_resume (struct pci_dev* dev)
+static int __maybe_unused ark_pci_resume(struct device *dev)
 {
-	struct fb_info *info = pci_get_drvdata(dev);
+	struct fb_info *info = dev_get_drvdata(dev);
 	struct arkfb_info *par = info->par;
 
 	dev_info(info->device, "resume\n");
@@ -1132,14 +1127,6 @@ static int ark_pci_resume (struct pci_dev* dev)
 	if (par->ref_count == 0)
 		goto fail;
 
-	pci_set_power_state(dev, PCI_D0);
-	pci_restore_state(dev);
-
-	if (pci_enable_device(dev))
-		goto fail;
-
-	pci_set_master(dev);
-
 	arkfb_set_par(info);
 	fb_set_suspend(info, 0);
 
@@ -1148,10 +1135,17 @@ static int ark_pci_resume (struct pci_dev* dev)
 	console_unlock();
 	return 0;
 }
-#else
-#define ark_pci_suspend NULL
-#define ark_pci_resume NULL
-#endif /* CONFIG_PM */
+
+static const struct dev_pm_ops ark_pci_pm_ops = {
+#ifdef CONFIG_PM_SLEEP
+	.suspend	= ark_pci_suspend,
+	.resume		= ark_pci_resume,
+	.freeze		= ark_pci_suspend,
+	.thaw		= ark_pci_resume,
+	.poweroff	= ark_pci_suspend,
+	.restore	= ark_pci_resume,
+#endif
+};
 
 /* List of boards that we are trying to support */
 
@@ -1168,8 +1162,7 @@ static struct pci_driver arkfb_pci_driver = {
 	.id_table	= ark_devices,
 	.probe		= ark_pci_probe,
 	.remove		= ark_pci_remove,
-	.suspend	= ark_pci_suspend,
-	.resume		= ark_pci_resume,
+	.driver.pm	= &ark_pci_pm_ops,
 };
 
 /* Cleanup */
-- 
2.27.0