linux-kernel - Re: [PATCH v5 1/3] PCI: rockchip: Add support for pcie wake irq

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Date:   Fri, 13 Oct 2017 15:21:41 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Bjorn Helgaas <helgaas@...nel.org>
Cc:     Jeffy Chen <jeffy.chen@...k-chips.com>,
        linux-kernel@...r.kernel.org, bhelgaas@...gle.com,
        Heiko Stuebner <heiko@...ech.de>, linux-pci@...r.kernel.org,
        shawn.lin@...k-chips.com, briannorris@...omium.org,
        dianders@...omium.org, linux-rockchip@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org,
        Tony Lindgren <tony@...mide.com>
Subject: Re: [PATCH v5 1/3] PCI: rockchip: Add support for pcie wake irq

[+cc Tony]

On Friday, October 13, 2017 5:04:41 AM CEST Bjorn Helgaas wrote:
> [+cc Rafael, linux-pm]
> 
> On Mon, Sep 11, 2017 at 11:10:27PM +0800, Jeffy Chen wrote:
> > Add support for PCIE_WAKE pin in rockchip pcie driver.
> > 
> > Signed-off-by: Jeffy Chen <jeffy.chen@...k-chips.com>
> > ---
> > 
> > Changes in v5:
> > Rebase
> > 
> > Changes in v3:
> > Fix error handling
> > 
> > Changes in v2:
> > Use dev_pm_set_dedicated_wake_irq
> >         -- Suggested by Brian Norris <briannorris@...omium.com>
> > 
> >  drivers/pci/host/pcie-rockchip.c | 19 +++++++++++++++++--
> >  1 file changed, 17 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/pci/host/pcie-rockchip.c b/drivers/pci/host/pcie-rockchip.c
> > index 9051c6c8fea4..a8b7272597a7 100644
> > --- a/drivers/pci/host/pcie-rockchip.c
> > +++ b/drivers/pci/host/pcie-rockchip.c
> > @@ -37,6 +37,7 @@
> >  #include <linux/pci_ids.h>
> >  #include <linux/phy/phy.h>
> >  #include <linux/platform_device.h>
> > +#include <linux/pm_wakeirq.h>
> >  #include <linux/reset.h>
> >  #include <linux/regmap.h>
> >  
> > @@ -995,6 +996,15 @@ static int rockchip_pcie_setup_irq(struct rockchip_pcie *rockchip)
> >  		return err;
> >  	}
> >  
> > +	/* Must init wakeup before setting dedicated wakeup irq. */
> > +	device_init_wakeup(dev, true);
> > +	irq = platform_get_irq_byname(pdev, "wakeup");
> > +	if (irq >= 0) {
> > +		err = dev_pm_set_dedicated_wake_irq(dev, irq);
> 
> I'm a little skeptical about dev_pm_set_dedicated_wake_irq(), not
> because I know anything at all about it, but because there are only
> five callers in the whole tree, three of which are in UART code, and
> none in anything resembling PCI code.
> 
> Is Rockchip really that special, or are we going about this the wrong
> way?
> 
> > +		if (err)
> > +			dev_err(dev, "failed to setup PCIe wakeup IRQ\n");
> > +	}
> > +
> >  	return 0;
> 
> The above could be structured as:
> 
>   irq = platform_get_irq_byname(pdev, "wakeup");
>   if (irq < 0)
>     return 0;
> 
>   device_init_wakeup(dev, true);
>   err = dev_pm_set_dedicated_wake_irq(dev, irq);
>   if (err) {
>     dev_pm_clear_wake_irq(dev);
>     device_init_wakeup(dev, false);
>   }
> 
>   return 0;
> 
> to unindent the mainline non-error code.
> 
> >  }
> >  
> > @@ -1542,11 +1552,11 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
> >  
> >  	err = rockchip_pcie_parse_dt(rockchip);
> >  	if (err)
> > -		return err;
> > +		goto err_disable_wake;
> >  
> >  	err = rockchip_pcie_enable_clocks(rockchip);
> >  	if (err)
> > -		return err;
> > +		goto err_disable_wake;
> >  
> >  	err = rockchip_pcie_set_vpcie(rockchip);
> >  	if (err) {
> > @@ -1656,6 +1666,9 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
> >  		regulator_disable(rockchip->vpcie0v9);
> >  err_set_vpcie:
> >  	rockchip_pcie_disable_clocks(rockchip);
> > +err_disable_wake:
> > +	dev_pm_clear_wake_irq(dev);
> > +	device_init_wakeup(dev, false);
> 
> I think this error cleanup should be done in rockchip_pcie_setup_irq()
> as shown above.  There's no real connection between
> rockchip_pcie_probe() and the wake setup.
> 
> >  	return err;
> >  }
> >  
> > @@ -1682,6 +1695,8 @@ static int rockchip_pcie_remove(struct platform_device *pdev)
> >  	if (!IS_ERR(rockchip->vpcie0v9))
> >  		regulator_disable(rockchip->vpcie0v9);
> >  
> > +	dev_pm_clear_wake_irq(dev);
> > +	device_init_wakeup(dev, false);
> >  	return 0;
> >  }
> >  
>