Re: [PATCH v6 2/2] can: m_can: Add hrtimer to generate software interrupt

[Judith Mendez]

Hello Marc,

On 5/19/23 2:16 AM, Marc Kleine-Budde wrote:
> On 18.05.2023 14:36:13, Judith Mendez wrote:
> > Add an hrtimer to MCAN class device. Each MCAN will have its own
> > hrtimer instantiated if there is no hardware interrupt found and
> > poll-interval property is defined in device tree M_CAN node.
> >
> > The hrtimer will generate a software interrupt every 1 ms. In
> > hrtimer callback, we check if there is a transaction pending by
> > reading a register, then process by calling the isr if there is.
> >
> > Signed-off-by: Judith Mendez <jm@xxxxxx>
>
> [...]

Missed this poll-interval, thanks.

> > diff --git a/drivers/net/can/m_can/m_can_platform.c b/drivers/net/can/m_can/m_can_platform.c
> > index 94dc82644113..3e60cebd9d12 100644
> > --- a/drivers/net/can/m_can/m_can_platform.c
> > +++ b/drivers/net/can/m_can/m_can_platform.c
> > @@ -5,6 +5,7 @@
> >   //
> >   // Copyright (C) 2018-19 Texas Instruments Incorporated - http://www.ti.com/
> >   
> > +#include <linux/hrtimer.h>
> >   #include <linux/phy/phy.h>
> >   #include <linux/platform_device.h>
> >   
> > @@ -96,12 +97,40 @@ static int m_can_plat_probe(struct platform_device *pdev)
> >   		goto probe_fail;
> >   
> >   	addr = devm_platform_ioremap_resource_byname(pdev, "m_can");
> > -	irq = platform_get_irq_byname(pdev, "int0");
> > -	if (IS_ERR(addr) || irq < 0) {
> > -		ret = -EINVAL;
> > +	if (IS_ERR(addr)) {
> > +		ret = PTR_ERR(addr);
> >   		goto probe_fail;
> >   	}
> >   
>
> As we don't use an explicit "poll-interval" anymore, this needs some
> cleanup. The flow should be (pseudo code, error handling omitted):
>
> if (device_property_present("interrupts") {
>          platform_get_irq_byname();
>          polling = false;
> } else {
>          hrtimer_init();
>          polling = true;
> }

Ok.

> > +	irq = platform_get_irq_byname_optional(pdev, "int0");
>
> Remove the "_optional" and....

On V2, you asked to add the _optional?.....

>  	irq = platform_get_irq_byname(pdev, "int0");

use platform_get_irq_byname_optional(), it doesn't print an error
message.

> > +	if (irq == -EPROBE_DEFER) {
> > +		ret = -EPROBE_DEFER;
> > +		goto probe_fail;
> > +	}
> > +
> > +	if (device_property_present(mcan_class->dev, "interrupts") ||
> > +	    device_property_present(mcan_class->dev, "interrupt-names"))
> > +		mcan_class->polling = false;
>
> ...move the platform_get_irq_byname() here

ok,

> > +	else
> > +		mcan_class->polling = true;
> > +
> > +	if (!mcan_class->polling && irq < 0) {
> > +		ret = -ENXIO;
> > +		dev_err_probe(mcan_class->dev, ret, "IRQ int0 not found, polling not activated\n");
> > +		goto probe_fail;
> > +	}
>
> Remove this check.

Should we not go to 'probe fail' if polling is not activated and irq is 
not found?

> > +
> > +	if (mcan_class->polling) {
> > +		if (irq > 0) {
> > +			mcan_class->polling = false;
> > +			dev_info(mcan_class->dev, "Polling enabled, using hardware IRQ\n");
>
> Remove this.

Remove the dev_info?

> > +		} else {
> > +			dev_dbg(mcan_class->dev, "Polling enabled, initialize hrtimer");
> > +			hrtimer_init(&mcan_class->hrtimer, CLOCK_MONOTONIC,
> > +				     HRTIMER_MODE_REL_PINNED);
>
> move this backwards, where you set "polling = true"

ok,
> > +		}
> > +	}
> > +
> >   	/* message ram could be shared */
> >   	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "message_ram");
> >   	if (!res) {
> > --
> > 2.17.1

- judith