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

Keerthy j-keerthy at ti.com
Wed Sep 26 21:55:52 PDT 2018



On Thursday 27 September 2018 05:01 AM, Tony Lindgren wrote:
> * Grygorii Strashko <grygorii.strashko at ti.com> [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?

This works pretty well with DS0 on am437x-gp-evm. Tested rtc wakeup,
wakeup using uart and touch. All of the work well.

https://pastebin.ubuntu.com/p/RJhJJKhJHX/

Also tested on beaglebone black DS0 works fine. Although there seems to
be an additional warning which was not seen before:

"l4-wkup-clkctrl:0008:0: failed to disable"

log: https://pastebin.ubuntu.com/p/Ns2WRdVkXS/

Also the above warning is present without/with this patch on [0].
No such warnings on am4 though.

[0]
https://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git/log/?h=omap-for-v4.20/dt-ti-sysc-tmp-testing

Regards,
Keerthy

> 
> 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),
>  	},
>  };
> 



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