Thread (34 messages) 34 messages, 4 authors, 2018-12-07

Re: [PATCH 0/4] Update am437x and am335x dts to probe with ti-sysc

From: Grygorii Strashko <grygorii.strashko@ti.com>
Date: 2018-09-27 19:11:44
Also in: linux-arm-kernel, linux-omap


On 09/26/2018 06:31 PM, Tony Lindgren wrote:
* Grygorii Strashko [off-list ref] [180926 21:41]:
quoted
On 09/26/2018 11:23 AM, Tony Lindgren wrote:
quoted
+static int __maybe_unused omap_i2c_suspend(struct device *dev)
+{
+	struct omap_i2c_dev *ddata = dev_get_drvdata(dev);
+	int error;
+
+	/* Is device still enabled because of autosuspend? */
+	if (ddata->is_suspended)
+		return 0;
Sry, but you can't do this. There is no sync between suspend and PM runtime.

quoted
+
+	/* Paired with call in omap_i2c_resume() */
+	error = pm_runtime_put_sync_suspend(dev);
This is nop!!! More over, in general you can't predict how many times pm_runtime_get was called and
what's the current value of usage_count.
Hmm yeah that's a good point.
quoted
To make things work the pm_runtime_force_xx() have to be used, or
like with omap_device, platform/bus code have to handle device state
at suspend_no_irq stage.
OK. So looks like the other i2c bus drivers have already solved it
with simply SET_NOIRQ_SYSTEM_SLEEP_PM_OPS which is along the lines
you're suggesting.

The following works for me, does it look OK to you?
it looks good, just curious if it will work both ti-sysc legacy/nonlegacy modes.
quoted hunk ↗ jump to hunk
8< ---------------------
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -1498,8 +1498,7 @@ static int omap_i2c_remove(struct platform_device *pdev)
  	return 0;
  }
  
-#ifdef CONFIG_PM
-static int omap_i2c_runtime_suspend(struct device *dev)
+static int __maybe_unused omap_i2c_runtime_suspend(struct device *dev)
  {
  	struct omap_i2c_dev *omap = dev_get_drvdata(dev);
  
@@ -1525,7 +1524,7 @@ static int omap_i2c_runtime_suspend(struct device *dev)
  	return 0;
  }
  
-static int omap_i2c_runtime_resume(struct device *dev)
+static int __maybe_unused omap_i2c_runtime_resume(struct device *dev)
  {
  	struct omap_i2c_dev *omap = dev_get_drvdata(dev);
  
@@ -1540,20 +1539,18 @@ static int omap_i2c_runtime_resume(struct device *dev)
  }
  
  static const struct dev_pm_ops omap_i2c_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				      pm_runtime_force_resume)
  	SET_RUNTIME_PM_OPS(omap_i2c_runtime_suspend,
  			   omap_i2c_runtime_resume, NULL)
  };
-#define OMAP_I2C_PM_OPS (&omap_i2c_pm_ops)
-#else
-#define OMAP_I2C_PM_OPS NULL
-#endif /* CONFIG_PM */
  
  static struct platform_driver omap_i2c_driver = {
  	.probe		= omap_i2c_probe,
  	.remove		= omap_i2c_remove,
  	.driver		= {
  		.name	= "omap_i2c",
-		.pm	= OMAP_I2C_PM_OPS,
+		.pm	= &omap_i2c_pm_ops,
  		.of_match_table = of_match_ptr(omap_i2c_of_match),
  	},
  };
-- 
regards,
-grygorii
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