sis-agp: convert to generic power management

Convert sis-agp from legacy PCI power management to the generic power
management framework.

Previously, sis-agp used legacy PCI power management, and agp_sis_suspend()
and agp_sis_resume() were responsible for both device-specific things and
generic PCI things:

  agp_sis_suspend
    pci_save_state(pdev)                <-- generic PCI
    pci_set_power_state(pdev, pci_choose_state(pdev, state)) <-- generic PCI

  agp_sis_resume
    pci_set_power_state(pdev, PCI_D0)   <-- generic PCI
    pci_restore_state(pdev)             <-- generic PCI
    sis_driver.configure()              <-- device-specific

With generic power management, the PCI bus PM methods do the generic PCI
things, and the driver needs only the device-specific part, i.e.,

  suspend_devices_and_enter
    dpm_suspend_start(PMSG_SUSPEND)
      pci_pm_suspend                    # PCI bus .suspend() method
        agp_sis_suspend                 <-- not needed at all; removed
    suspend_enter
      dpm_suspend_noirq(PMSG_SUSPEND)
        pci_pm_suspend_noirq            # PCI bus .suspend_noirq() method
          pci_save_state                <-- generic PCI
          pci_prepare_to_sleep          <-- generic PCI
            pci_set_power_state
    ...
    dpm_resume_end(PMSG_RESUME)
      pci_pm_resume                     # PCI bus .resume() method
        pci_restore_standard_config
          pci_set_power_state(PCI_D0)   <-- generic PCI
          pci_restore_state             <-- generic PCI
        agp_sis_resume                  # dev->driver->pm->resume
          sis_driver.configure()        <-- device-specific

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20211208193305.147072-3-helgaas@kernel.org
Signed-off-by: Vaibhav Gupta <vaibhavgupta40@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/char/agp/sis-agp.c b/drivers/char/agp/sis-agp.c
index 14909fc5d767f42d6039a2c58398e38ad58c680e..f8a02f4bef1bf3b97c700136f0c8a58e927cdd5d 100644 (file)
--- a/drivers/char/agp/sis-agp.c
+++ b/drivers/char/agp/sis-agp.c
@@ -217,26 +217,14 @@ static void agp_sis_remove(struct pci_dev *pdev)
        agp_put_bridge(bridge);
 }
 
-#ifdef CONFIG_PM
+#define agp_sis_suspend NULL
 
-static int agp_sis_suspend(struct pci_dev *pdev, pm_message_t state)
+static int __maybe_unused agp_sis_resume(
+       __attribute__((unused)) struct device *dev)
 {
-       pci_save_state(pdev);
-       pci_set_power_state(pdev, pci_choose_state(pdev, state));
-
-       return 0;
-}
-
-static int agp_sis_resume(struct pci_dev *pdev)
-{
-       pci_set_power_state(pdev, PCI_D0);
-       pci_restore_state(pdev);
-
        return sis_driver.configure();
 }
 
-#endif /* CONFIG_PM */
-
 static const struct pci_device_id agp_sis_pci_table[] = {
        {
                .class          = (PCI_CLASS_BRIDGE_HOST << 8),
@@ -419,15 +407,14 @@ static const struct pci_device_id agp_sis_pci_table[] = {
 
 MODULE_DEVICE_TABLE(pci, agp_sis_pci_table);
 
+static SIMPLE_DEV_PM_OPS(agp_sis_pm_ops, agp_sis_suspend, agp_sis_resume);
+
 static struct pci_driver agp_sis_pci_driver = {
        .name           = "agpgart-sis",
        .id_table       = agp_sis_pci_table,
        .probe          = agp_sis_probe,
        .remove         = agp_sis_remove,
-#ifdef CONFIG_PM
-       .suspend        = agp_sis_suspend,
-       .resume         = agp_sis_resume,
-#endif
+       .driver.pm      = &agp_sis_pm_ops,
 };
 
 static int __init agp_sis_init(void)