Re: [PATCH v3 1/2] i2c: davinci: Add PM Runtime Support

On 09/11/2017 06:29 AM, Sekhar Nori wrote:

On Friday 08 September 2017 11:24 PM, Franklin S Cooper Jr wrote:

quoted

66AK2G has I2C instances that are not apart of the ALWAYS_ON power domain
like other Keystone 2 SoCs and OMAPL138. Therefore, pm_runtime

unlike ?

quoted

is required to insure the power domain used by the specific I2C instance is
properly turned on along with its functional clock.

Signed-off-by: Franklin S Cooper Jr <redacted>
---
Version 3 changes:
Remove several statements that set clk to NULL
Fix error path

 drivers/i2c/busses/i2c-davinci.c | 64 +++++++++++++++++++++++++++++++++-------
 1 file changed, 53 insertions(+), 11 deletions(-)

quoted

@@ -802,12 +821,22 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 	dev->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(dev->clk))
 		return PTR_ERR(dev->clk);
-	clk_prepare_enable(dev->clk);
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	dev->base = devm_ioremap_resource(&pdev->dev, mem);
 	if (IS_ERR(dev->base)) {
-		r = PTR_ERR(dev->base);
+		return PTR_ERR(dev->base);
+	}
+
+	pm_runtime_set_autosuspend_delay(dev->dev,
+					 DAVINCI_I2C_PM_TIMEOUT);
+	pm_runtime_use_autosuspend(dev->dev);
+
+	pm_runtime_enable(dev->dev);
+
+	r = pm_runtime_get_sync(dev->dev);
+	if (r < 0) {
+		dev_err(dev->dev, "failed to runtime_get device: %d\n", r);
 		goto err_unuse_clocks;

You end up doing a pm_runtime_put_sync() on failure here, instead of
pm_runtime_put_noidle() like rest of the patch.

May be handle this failure here instead of relying on the goto path.

Ok

quoted

 	}
 

@@ -849,27 +878,40 @@ static int davinci_i2c_probe(struct platform_device *pdev)
 	if (r)
 		goto err_unuse_clocks;
 
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+
 	return 0;
 
 err_unuse_clocks:
-	clk_disable_unprepare(dev->clk);
-	dev->clk = NULL;
+	pm_runtime_dont_use_autosuspend(dev->dev);
+	pm_runtime_put_sync(dev->dev);
+	pm_runtime_disable(dev->dev);
+
 	return r;
 }

Thanks,
Sekhar