[PATCH] i2c: imx: add irqf_no_suspend

[PATCH] i2c: imx: add irqf_no_suspend

[Alifer Moraes]

From: gaopan <b54642@freescale.com>

The i2c irq is masked when pcie starts a i2c transfer process
during noirq suspend stage. As a result, i2c transfer fails.
To solve the problem, IRQF_NO_SUSPEND is added to i2c bus.

Signed-off-by: Gao Pan <b54642@freescale.com>
Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>
---
 drivers/i2c/busses/i2c-imx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 27f969b3dc07..fcc09a1e7f44 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -1478,7 +1478,8 @@ static int i2c_imx_probe(struct platform_device *pdev)
 		goto rpm_disable;
 
 	/* Request IRQ */
-	ret = request_threaded_irq(irq, i2c_imx_isr, NULL, IRQF_SHARED,
+	ret = request_threaded_irq(irq, i2c_imx_isr, NULL,
+				   IRQF_SHARED | IRQF_NO_SUSPEND,
 				   pdev->name, i2c_imx);
 	if (ret) {
 		dev_err(&pdev->dev, "can't claim irq %d\n", irq);
-- 
2.25.1

Re: [PATCH] i2c: imx: add irqf_no_suspend

[Oleksij Rempel]

On Mon, Mar 07, 2022 at 11:36:30AM -0300, Alifer Moraes wrote:
> From: gaopan <b54642@freescale.com>
> 
> The i2c irq is masked when pcie starts a i2c transfer process
> during noirq suspend stage. As a result, i2c transfer fails.
> To solve the problem, IRQF_NO_SUSPEND is added to i2c bus.
> 
> Signed-off-by: Gao Pan <b54642@freescale.com>
> Signed-off-by: Fugang Duan <B38611@freescale.com>
> Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>

Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Thank you!

> ---
>  drivers/i2c/busses/i2c-imx.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 27f969b3dc07..fcc09a1e7f44 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -1478,7 +1478,8 @@ static int i2c_imx_probe(struct platform_device *pdev)
>  		goto rpm_disable;
>  
>  	/* Request IRQ */
> -	ret = request_threaded_irq(irq, i2c_imx_isr, NULL, IRQF_SHARED,
> +	ret = request_threaded_irq(irq, i2c_imx_isr, NULL,
> +				   IRQF_SHARED | IRQF_NO_SUSPEND,
>  				   pdev->name, i2c_imx);
>  	if (ret) {
>  		dev_err(&pdev->dev, "can't claim irq %d\n", irq);
> -- 
> 2.25.1
> 
> 
> 

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Re: (EXT) [PATCH] i2c: imx: add irqf_no_suspend

[Alexander Stein]

Hallo,

Am Montag, 7. März 2022, 15:36:30 CET schrieb Alifer Moraes:
> From: gaopan <b54642@freescale.com>
> 
> The i2c irq is masked when pcie starts a i2c transfer process
> during noirq suspend stage. As a result, i2c transfer fails.
> To solve the problem, IRQF_NO_SUSPEND is added to i2c bus.
> 
> Signed-off-by: Gao Pan <b54642@freescale.com>
> Signed-off-by: Fugang Duan <B38611@freescale.com>
> Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>
> ---
>  drivers/i2c/busses/i2c-imx.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
> index 27f969b3dc07..fcc09a1e7f44 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -1478,7 +1478,8 @@ static int i2c_imx_probe(struct platform_device *pdev)
> goto rpm_disable;
> 
>  	/* Request IRQ */
> -	ret = request_threaded_irq(irq, i2c_imx_isr, NULL, IRQF_SHARED,
> +	ret = request_threaded_irq(irq, i2c_imx_isr, NULL,
> +				   IRQF_SHARED | IRQF_NO_SUSPEND,
>  				   pdev->name, i2c_imx);
>  	if (ret) {
>  		dev_err(&pdev->dev, "can't claim irq %d\n", irq);


I stumbled across Documentation/power/suspend-and-interrupts.rst which states:
> For this reason, using IRQF_NO_SUSPEND and IRQF_SHARED at the
> same time should be avoided.
Given this IMHO at least a comment should be inserted why this is fine. I dont 
have a full picture about the situation, but to me it seems there is a 
reference missing, or why/how does some PCIe start some I2C transfer when the
controller is suspended already? Do I miss something?

Best regards,
Alexander

Re: (EXT) [PATCH] i2c: imx: add irqf_no_suspend

[Wolfram Sang]

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Hi everyone,

> > The i2c irq is masked when pcie starts a i2c transfer process
> > during noirq suspend stage. As a result, i2c transfer fails.
> > To solve the problem, IRQF_NO_SUSPEND is added to i2c bus.
> > 
> > Signed-off-by: Gao Pan <b54642@freescale.com>
> > Signed-off-by: Fugang Duan <B38611@freescale.com>
> > Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>

The SoB from Alifer Moraes is missing, too.

> > goto rpm_disable;
> > 
> >  	/* Request IRQ */
> > -	ret = request_threaded_irq(irq, i2c_imx_isr, NULL, IRQF_SHARED,
> > +	ret = request_threaded_irq(irq, i2c_imx_isr, NULL,
> > +				   IRQF_SHARED | IRQF_NO_SUSPEND,
> >  				   pdev->name, i2c_imx);
> >  	if (ret) {
> >  		dev_err(&pdev->dev, "can't claim irq %d\n", irq);
> 
> 
> I stumbled across Documentation/power/suspend-and-interrupts.rst which states:
> > For this reason, using IRQF_NO_SUSPEND and IRQF_SHARED at the
> > same time should be avoided.
> Given this IMHO at least a comment should be inserted why this is fine. I dont 
> have a full picture about the situation, but to me it seems there is a 
> reference missing, or why/how does some PCIe start some I2C transfer when the
> controller is suspended already? Do I miss something?

Thank you for this comment, Alexander. I second you, this needs
explanation.

Happy hacking,

   Wolfram


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Re: [PATCH] i2c: imx: add irqf_no_suspend

[Pierluigi Passaro]

Hi All,

> Hi everyone,

> > > The i2c irq is masked when pcie starts a i2c transfer process
> > > during noirq suspend stage. As a result, i2c transfer fails.
> > > To solve the problem, IRQF_NO_SUSPEND is added to i2c bus.
> > > 
> > > Signed-off-by: Gao Pan <b54642@freescale.com>
> > > Signed-off-by: Fugang Duan <B38611@freescale.com>
> > > Signed-off-by: Vipul Kumar <vipul_kumar@mentor.com>

> The SoB from Alifer Moraes is missing, too.

> > > goto rpm_disable;
> > > 
> > >      /* Request IRQ */
> > > -   ret = request_threaded_irq(irq, i2c_imx_isr, NULL, IRQF_SHARED,
> > > +   ret = request_threaded_irq(irq, i2c_imx_isr, NULL,
> > > +                              IRQF_SHARED | IRQF_NO_SUSPEND,
> > >                                 pdev->name, i2c_imx);
> > >      if (ret) {
> > >              dev_err(&pdev->dev, "can't claim irq %d\n", irq);
> > 
> > 
> > I stumbled across Documentation/power/suspend-and-interrupts.rst which states:
> > > For this reason, using IRQF_NO_SUSPEND and IRQF_SHARED at the
> > > same time should be avoided.
> > Given this IMHO at least a comment should be inserted why this is fine. I dont 
> > have a full picture about the situation, but to me it seems there is a 
> > reference missing, or why/how does some PCIe start some I2C transfer when the
> > controller is suspended already? Do I miss something?

This patch has been introduced to fix the following behavior.
HW conditions
- Variscite DART-MX8M on DT8MCustomBoard v2.x or higher.
- The PCIe connector uses a reset pin coming from a GPIO expander connected to the I2C bus.
SW behavior
- Upon wake-up, the PCIe try toggling the reset pins, but the GPIO expander / I2C bus are still suspended, leading to a PCIe wake-up failure.
From our investigation, we can't identify a way to postpone PCIe wake-up after I2C wake-up.
This patch is still present in latest NXP kernel 5.15, but please let me know if you think this should be approached / fixed in a different way.

Thanks
Regards
Pier


> Thank you for this comment, Alexander. I second you, this needs
> explanation.

> Happy hacking,
>   Wolfram