[Linux-kernel-mentees] [PATCH v3 4/6] cx88: use generic power management

Vaibhav Gupta vaibhavgupta40 at gmail.com
Fri Jul 17 07:34:34 UTC 2020


With legacy PM, drivers themselves were responsible for managing the
device's power states and takes care of register states.

After upgrading to the generic structure, PCI core will take care of
required tasks and drivers should do only device-specific operations.

The driver was invoking PCI helper functions like pci_save/restore_state(),
pci_enable/disable_device() and pci_set_power_state(), which is not
recommended.

Compile-tested only.

Signed-off-by: Vaibhav Gupta <vaibhavgupta40 at gmail.com>
---
 drivers/media/pci/cx88/cx88-video.c | 58 ++++++++---------------------
 1 file changed, 15 insertions(+), 43 deletions(-)

diff --git a/drivers/media/pci/cx88/cx88-video.c b/drivers/media/pci/cx88/cx88-video.c
index ba0e9660a047..ab55e3fafe00 100644
--- a/drivers/media/pci/cx88/cx88-video.c
+++ b/drivers/media/pci/cx88/cx88-video.c
@@ -385,8 +385,7 @@ static int start_video_dma(struct cx8800_dev    *dev,
 	return 0;
 }
 
-#ifdef CONFIG_PM
-static int stop_video_dma(struct cx8800_dev    *dev)
+static int __maybe_unused stop_video_dma(struct cx8800_dev    *dev)
 {
 	struct cx88_core *core = dev->core;
 
@@ -402,7 +401,7 @@ static int stop_video_dma(struct cx8800_dev    *dev)
 	return 0;
 }
 
-static int restart_video_queue(struct cx8800_dev    *dev,
+static int __maybe_unused restart_video_queue(struct cx8800_dev    *dev,
 			       struct cx88_dmaqueue *q)
 {
 	struct cx88_buffer *buf;
@@ -415,7 +414,6 @@ static int restart_video_queue(struct cx8800_dev    *dev,
 	}
 	return 0;
 }
-#endif
 
 /* ------------------------------------------------------------------ */
 
@@ -1551,10 +1549,9 @@ static void cx8800_finidev(struct pci_dev *pci_dev)
 	kfree(dev);
 }
 
-#ifdef CONFIG_PM
-static int cx8800_suspend(struct pci_dev *pci_dev, pm_message_t state)
+static int __maybe_unused cx8800_suspend(struct device *dev_d)
 {
-	struct cx8800_dev *dev = pci_get_drvdata(pci_dev);
+	struct cx8800_dev *dev = dev_get_drvdata(dev_d);
 	struct cx88_core *core = dev->core;
 	unsigned long flags;
 
@@ -1575,40 +1572,17 @@ static int cx8800_suspend(struct pci_dev *pci_dev, pm_message_t state)
 	/* FIXME -- shutdown device */
 	cx88_shutdown(core);
 
-	pci_save_state(pci_dev);
-	if (pci_set_power_state(pci_dev,
-				pci_choose_state(pci_dev, state)) != 0) {
-		pci_disable_device(pci_dev);
-		dev->state.disabled = 1;
-	}
+	dev->state.disabled = 1;
 	return 0;
 }
 
-static int cx8800_resume(struct pci_dev *pci_dev)
+static int __maybe_unused cx8800_resume(struct device *dev_d)
 {
-	struct cx8800_dev *dev = pci_get_drvdata(pci_dev);
+	struct cx8800_dev *dev = dev_get_drvdata(dev_d);
 	struct cx88_core *core = dev->core;
 	unsigned long flags;
-	int err;
 
-	if (dev->state.disabled) {
-		err = pci_enable_device(pci_dev);
-		if (err) {
-			pr_err("can't enable device\n");
-			return err;
-		}
-
-		dev->state.disabled = 0;
-	}
-	err = pci_set_power_state(pci_dev, PCI_D0);
-	if (err) {
-		pr_err("can't set power state\n");
-		pci_disable_device(pci_dev);
-		dev->state.disabled = 1;
-
-		return err;
-	}
-	pci_restore_state(pci_dev);
+	dev->state.disabled = 0;
 
 	/* FIXME: re-initialize hardware */
 	cx88_reset(core);
@@ -1631,7 +1605,6 @@ static int cx8800_resume(struct pci_dev *pci_dev)
 
 	return 0;
 }
-#endif
 
 /* ----------------------------------------------------------- */
 
@@ -1647,15 +1620,14 @@ static const struct pci_device_id cx8800_pci_tbl[] = {
 };
 MODULE_DEVICE_TABLE(pci, cx8800_pci_tbl);
 
+static SIMPLE_DEV_PM_OPS(cx8800_pm_ops, cx8800_suspend, cx8800_resume);
+
 static struct pci_driver cx8800_pci_driver = {
-	.name     = "cx8800",
-	.id_table = cx8800_pci_tbl,
-	.probe    = cx8800_initdev,
-	.remove   = cx8800_finidev,
-#ifdef CONFIG_PM
-	.suspend  = cx8800_suspend,
-	.resume   = cx8800_resume,
-#endif
+	.name      = "cx8800",
+	.id_table  = cx8800_pci_tbl,
+	.probe     = cx8800_initdev,
+	.remove    = cx8800_finidev,
+	.driver.pm = &cx8800_pm_ops,
 };
 
 module_pci_driver(cx8800_pci_driver);
-- 
2.27.0



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