Re: [PATCH] of/irq: introduce of_has_named_irqs helper

[Vignesh R]

Hi Dmitry,

On 07/25/2015 01:46 AM, Dmitry Torokhov wrote:
> On Fri, Jul 24, 2015 at 12:26:19PM -0700, Dmitry Torokhov wrote:
>> On Fri, Jul 24, 2015 at 02:14:57PM -0500, Rob Herring wrote:
>>> On Fri, Jul 24, 2015 at 1:26 PM, Dmitry Torokhov
>>> <dmitry.torokhov@xxxxxxxxx> wrote:
>>>> Sometimes drivers might wish to transition from index-based to named
>>>> interrupt descriptions. To aid in decision-making when parsing device
>>>> tree data let's provide a helper that will indicate the scheme that is
>>>> being used.
>>>
>>> Generally, IRQs are retrieved by platform_get_irq or
>>> platform_get_irq_byname. Drivers should not call the of_irq_*
>>> functions directly in most cases.
>>
>> That would be true for platform drivers, but not all devices are
>> platform devices.
>>
>>>
>>>>
>>>> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
>>>> ---
>>>>
>>>> The intent is to it like this:
>>>>
>>>>         if (of_has_named_irqs(np) {
>>>>                 /* Wake IRQ is optional */
>>>>                 dev->wakeirq = of_irq_get_byname(np, "wakeup");
>>>>                 if (dev->wakeirq < 0 && dev->wakeirq != -ENODATA)
>>>>                         return dev->wakeirq;
>>>>         }
>>>
>>> of_irq_get_byname will already return an error if the property is not
>>> present. Use that.
>>
>> I do not like that it returns -EINVAL when property is missing, can we
>> change it to return -ENODATA (so it is the same as when the property is
>> defined but such name is missing)?
> 
> So here is what I had in mind.. It is based on recent patch by Vignesh
> for pixcir touchscreen, but I think it should be made available to all
> I2C devices. Completely untested at the moment.
> 

Thanks for the patch! I tested this on am437x-gp-evm and the
suspend/resume worked fine (below patch + $subject patch). I was able to
wake the system from low power state using touchscreen. Also verified
module insertion and removal. One comment though, please see below.

> ---
>  drivers/i2c/i2c-core.c |   43 +++++++++++++++++++++++++++++++++++++------
>  1 file changed, 37 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index e6d4935..3971461 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -47,6 +47,7 @@
>  #include <linux/rwsem.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/pm_domain.h>
> +#include <linux/pm_wakeirq.h>
>  #include <linux/acpi.h>
>  #include <linux/jump_label.h>
>  #include <asm/uaccess.h>
> @@ -631,6 +632,7 @@ static int i2c_device_probe(struct device *dev)
>  {
>  	struct i2c_client	*client = i2c_verify_client(dev);
>  	struct i2c_driver	*driver;
> +	int wakeirq = 0;
>  	int status;
>  
>  	if (!client)
> @@ -639,11 +641,13 @@ static int i2c_device_probe(struct device *dev)
>  	if (!client->irq) {
>  		int irq = -ENOENT;
>  
> -		if (dev->of_node)
> -			irq = of_irq_get(dev->of_node, 0);
> -		else if (ACPI_COMPANION(dev))
> +		if (dev->of_node) {
> +			irq = of_has_named_irqs(dev->of_node) ?
> +				of_irq_get_byname(dev->of_node, "irq") :
> +				of_irq_get(dev->of_node, 0);
> +		} else if (ACPI_COMPANION(dev)) {
>  			irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
> -
> +		}
>  		if (irq == -EPROBE_DEFER)
>  			return irq;
>  		if (irq < 0)
> @@ -652,6 +656,15 @@ static int i2c_device_probe(struct device *dev)
>  		client->irq = irq;
>  	}
>  
> +	if (dev->of_node && of_has_named_irqs(dev->of_node)) {
> +		wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
> +		if (wakeirq < 0) {
> +			if (wakeirq != -ENODATA)
> +				return wakeirq;
> +			wakeirq = 0;
> +		}
> +	}
> +
>  	driver = to_i2c_driver(dev->driver);
>  	if (!driver->probe || !driver->id_table)
>  		return -ENODEV;
> @@ -659,20 +672,34 @@ static int i2c_device_probe(struct device *dev)
>  	if (!device_can_wakeup(&client->dev))
>  		device_init_wakeup(&client->dev,
>  					client->flags & I2C_CLIENT_WAKE);
> +
> +	status = wakeirq > 0 ?
> +			dev_pm_set_dedicated_wake_irq(dev, wakeirq) :
> +			(client->irq > 0 ?
> +				dev_pm_set_wake_irq(dev, client->irq) : 0);

Above code tries to register wakeirq irrespective of whether the device
is specified as wakeup-source in the dt or not. Hence, I see warn
messages from every i2c device that has irq line but hasn't declared
itself as wakeup-source:
For example tps is on i2c:
[    1.961613] tps65218 0-0024: forgot to call call device_init_wakeup?
[    1.968340] tps65218 0-0024: failed to set up wakeup irq

May be you can register wakeup-source only if I2C_CLIENT_WAKE flag is
set in client->flags?

-- 
Regards
Vignesh
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