[Linux-kernel-mentees] [PATCH v2] scsi: stex: 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/scsi/stex.c | 37 +++++++++++++++++++++++++++++++------
 1 file changed, 31 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/stex.c b/drivers/scsi/stex.c
index d4f10c0d813c..5ef6f3cbac11 100644
--- a/drivers/scsi/stex.c
+++ b/drivers/scsi/stex.c
@@ -1972,9 +1972,9 @@ static int stex_choice_sleep_mic(struct st_hba *hba, pm_message_t state)
 	}
 }
 
-static int stex_suspend(struct pci_dev *pdev, pm_message_t state)
+static int stex_suspend_late(struct device *dev, pm_message_t state)
 {
-	struct st_hba *hba = pci_get_drvdata(pdev);
+	struct st_hba *hba = dev_get_drvdata(dev);
 
 	if ((hba->cardtype == st_yel || hba->cardtype == st_P3)
 		&& hba->supports_pm == 1)
@@ -1984,9 +1984,24 @@ static int stex_suspend(struct pci_dev *pdev, pm_message_t state)
 	return 0;
 }
 
-static int stex_resume(struct pci_dev *pdev)
+static int __maybe_unused stex_suspend(struct device *dev)
 {
-	struct st_hba *hba = pci_get_drvdata(pdev);
+	return stex_suspend_late(dev, PMSG_SUSPEND);
+}
+
+static int __maybe_unused stex_hibernate(struct device *dev)
+{
+	return stex_suspend_late(dev, PMSG_HIBERNATE);
+}
+
+static int __maybe_unused stex_freeze(struct device *dev)
+{
+	return stex_suspend_late(dev, PMSG_FREEZE);
+}
+
+static int __maybe_unused stex_resume(struct device *dev)
+{
+	struct st_hba *hba = dev_get_drvdata(dev);
 
 	hba->mu_status = MU_STATE_STARTING;
 	stex_handshake(hba);
@@ -2000,14 +2015,24 @@ static int stex_halt(struct notifier_block *nb, unsigned long event, void *buf)
 }
 MODULE_DEVICE_TABLE(pci, stex_pci_tbl);
 
+static const struct dev_pm_ops stex_pm_ops = {
+#ifdef CONFIG_PM_SLEEP
+	.suspend	= stex_suspend,
+	.resume		= stex_resume,
+	.freeze		= stex_freeze,
+	.thaw		= stex_resume,
+	.poweroff	= stex_hibernate,
+	.restore	= stex_resume,
+#endif
+};
+
 static struct pci_driver stex_pci_driver = {
 	.name		= DRV_NAME,
 	.id_table	= stex_pci_tbl,
 	.probe		= stex_probe,
 	.remove		= stex_remove,
 	.shutdown	= stex_shutdown,
-	.suspend	= stex_suspend,
-	.resume		= stex_resume,
+	.driver.pm	= &stex_pm_ops,
 };
 
 static int __init stex_init(void)
-- 
2.27.0