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

From: [email-masked] (Tony Lindgren)
Date: Wed, 26 Sep 2018 16:31:11 -0700

* Grygorii Strashko <[email-masked]> [180926 21:41]:
> On 09/26/2018 11:23 AM, Tony Lindgren wrote:
> > +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.
> 
> 
> > +
> > +	/* 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.

> 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?

Regards,

Tony

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),
 	},
 };
-- 
2.19.0