[PATCH 1/4] i2c: nvidia-gpu: add runtime pm support

[Ajay Gupta <ajaykuee@gmail.com>]

From: Ajay Gupta <ajayg@nvidia.com>

Enable runtime pm support with autosuspend delay of three second.
This is to make sure I2C client device Cypress CCGx has completed
all transaction.

Signed-off-by: Ajay Gupta <ajayg@nvidia.com>
---
 drivers/i2c/busses/i2c-nvidia-gpu.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/busses/i2c-nvidia-gpu.c b/drivers/i2c/busses/i2c-nvidia-gpu.c
index 1c8f708f212b..9d347583f8dc 100644
--- a/drivers/i2c/busses/i2c-nvidia-gpu.c
+++ b/drivers/i2c/busses/i2c-nvidia-gpu.c
@@ -175,6 +175,7 @@ static int gpu_i2c_master_xfer(struct i2c_adapter *adap,
 	 * The controller supports maximum 4 byte read due to known
 	 * limitation of sending STOP after every read.
 	 */
+	pm_runtime_get_sync(i2cd->dev);
 	for (i = 0; i < num; i++) {
 		if (msgs[i].flags & I2C_M_RD) {
 			/* program client address before starting read */
@@ -189,7 +190,7 @@ static int gpu_i2c_master_xfer(struct i2c_adapter *adap,
 			status = gpu_i2c_start(i2cd);
 			if (status < 0) {
 				if (i == 0)
-					return status;
+					goto exit;
 				goto stop;
 			}
 
@@ -206,13 +207,18 @@ static int gpu_i2c_master_xfer(struct i2c_adapter *adap,
 	}
 	status = gpu_i2c_stop(i2cd);
 	if (status < 0)
-		return status;
+		goto exit;
 
+	pm_runtime_mark_last_busy(i2cd->dev);
+	pm_runtime_put_autosuspend(i2cd->dev);
 	return i;
 stop:
 	status2 = gpu_i2c_stop(i2cd);
 	if (status2 < 0)
 		dev_err(i2cd->dev, "i2c stop failed %d\n", status2);
+exit:
+	pm_runtime_mark_last_busy(i2cd->dev);
+	pm_runtime_put_autosuspend(i2cd->dev);
 	return status;
 }
 
@@ -332,6 +338,11 @@ static int gpu_i2c_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		goto del_adapter;
 	}
 
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 3000);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_put_autosuspend(&pdev->dev);
+	pm_runtime_allow(&pdev->dev);
+
 	return 0;
 
 del_adapter:
@@ -345,10 +356,16 @@ static void gpu_i2c_remove(struct pci_dev *pdev)
 {
 	struct gpu_i2c_dev *i2cd = dev_get_drvdata(&pdev->dev);
 
+	pm_runtime_get_noresume(i2cd->dev);
 	i2c_del_adapter(&i2cd->adapter);
 	pci_free_irq_vectors(pdev);
 }
 
+static int gpu_i2c_suspend(struct device *dev)
+{
+	return 0;
+}
+
 static __maybe_unused int gpu_i2c_resume(struct device *dev)
 {
 	struct gpu_i2c_dev *i2cd = dev_get_drvdata(dev);
@@ -357,7 +374,8 @@ static __maybe_unused int gpu_i2c_resume(struct device *dev)
 	return 0;
 }
 
-static UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, NULL, gpu_i2c_resume, NULL);
+static UNIVERSAL_DEV_PM_OPS(gpu_i2c_driver_pm, gpu_i2c_suspend, gpu_i2c_resume,
+			    NULL);
 
 static struct pci_driver gpu_i2c_driver = {
 	.name		= "nvidia-gpu",
-- 
2.17.1