linux-kernel - Re: [PATCH 06/20] usb: host: ehci-sead3: Support probing using device tree

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Date:	Tue, 9 Aug 2016 16:08:48 +0200
From:	Jonas Gorski <jonas.gorski@...il.com>
To:	Paul Burton <paul.burton@...tec.com>
Cc:	MIPS Mailing List <linux-mips@...ux-mips.org>,
	Ralf Baechle <ralf@...ux-mips.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Alan Stern <stern@...land.harvard.edu>,
	linux-usb@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 06/20] usb: host: ehci-sead3: Support probing using device tree

Hi,

On 9 August 2016 at 14:35, Paul Burton <paul.burton@...tec.com> wrote:
> Introduce support for probing the SEAD3 EHCI driver using device tree.
>
> Signed-off-by: Paul Burton <paul.burton@...tec.com>
> ---
>
>  drivers/usb/host/ehci-sead3.c | 29 +++++++++++++++++++++++------
>  1 file changed, 23 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/usb/host/ehci-sead3.c b/drivers/usb/host/ehci-sead3.c
> index 3d86cc2..05db1ae 100644
> --- a/drivers/usb/host/ehci-sead3.c
> +++ b/drivers/usb/host/ehci-sead3.c
> @@ -20,6 +20,7 @@
>   */
>
>  #include <linux/err.h>
> +#include <linux/of_irq.h>
>  #include <linux/platform_device.h>
>
>  static int ehci_sead3_setup(struct usb_hcd *hcd)
> @@ -96,15 +97,25 @@ static int ehci_hcd_sead3_drv_probe(struct platform_device *pdev)
>  {
>         struct usb_hcd *hcd;
>         struct resource *res;
> -       int ret;
> +       int ret, irq;
>
>         if (usb_disabled())
>                 return -ENODEV;
>
> -       if (pdev->resource[1].flags != IORESOURCE_IRQ) {
> -               pr_debug("resource[1] is not IORESOURCE_IRQ");
> -               return -ENOMEM;
> +       if (pdev->dev.of_node) {
> +               irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
> +               if (!irq) {
> +                       dev_err(&pdev->dev, "failed to map IRQ\n");
> +                       return -ENODEV;
> +               }
> +       } else {
> +               if (pdev->resource[1].flags != IORESOURCE_IRQ) {
> +                       pr_debug("resource[1] is not IORESOURCE_IRQ");
> +                       return -ENOMEM;
> +               }
> +               irq = pdev->resource[1].start;
>         }
> +

Why not just use platform_get_irq(pdev, 0) instead of this whole
block? Then you wouldn't need to care anymore whether resource 1 is
the IRQ resource (and avoid a potential overrun when the device has
only one resource), or if it is probed through of.

>         hcd = usb_create_hcd(&ehci_sead3_hc_driver, &pdev->dev, "SEAD-3");
>         if (!hcd)
>                 return -ENOMEM;
> @@ -121,8 +132,7 @@ static int ehci_hcd_sead3_drv_probe(struct platform_device *pdev)
>         /* Root hub has integrated TT. */
>         hcd->has_tt = 1;
>
> -       ret = usb_add_hcd(hcd, pdev->resource[1].start,
> -                         IRQF_SHARED);
> +       ret = usb_add_hcd(hcd, irq, IRQF_SHARED);
>         if (ret == 0) {
>                 platform_set_drvdata(pdev, hcd);
>                 device_wakeup_enable(hcd->self.controller);
> @@ -172,12 +182,19 @@ static const struct dev_pm_ops sead3_ehci_pmops = {
>  #define SEAD3_EHCI_PMOPS NULL
>  #endif
>
> +static const struct of_device_id sead3_ehci_of_match[] = {
> +       { .compatible = "mti,sead3-ehci" },

I don't see this compatible documented anywhere, please add binding
documentation for it first (and CC devicetree@...r ).

> +       {},
> +};
> +MODULE_DEVICE_TABLE(of, sead3_ehci_of_match);
> +
>  static struct platform_driver ehci_hcd_sead3_driver = {
>         .probe          = ehci_hcd_sead3_drv_probe,
>         .remove         = ehci_hcd_sead3_drv_remove,
>         .shutdown       = usb_hcd_platform_shutdown,
>         .driver = {
>                 .name   = "sead3-ehci",
> +               .of_match_table = sead3_ehci_of_match,
>                 .pm     = SEAD3_EHCI_PMOPS,
>         }
>  };

Regards
Jonas