From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ezequiel Garcia Subject: Re: [PATCH v2 05/15] watchdog: orion: Make RSTOUT register a separate resource Date: Wed, 22 Jan 2014 15:01:01 -0300 Message-ID: <20140122180100.GE27273@localhost> References: <1390295561-3466-1-git-send-email-ezequiel.garcia@free-electrons.com> <1390295561-3466-6-git-send-email-ezequiel.garcia@free-electrons.com> <20140121233321.GR18269@obsidianresearch.com> <3176358.2QFcJHj0fv@wuerfel> <20140122162136.GA27273@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <20140122162136.GA27273@localhost> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Arnd Bergmann , Jason Gunthorpe Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Lior Amsalem , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-watchdog-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tawfik Bayouk , Andrew Lunn , Wim Van Sebroeck , Gregory Clement , Sebastian Hesselbarth , Thomas Petazzoni , Jason Cooper List-Id: devicetree@vger.kernel.org On Wed, Jan 22, 2014 at 01:21:36PM -0300, Ezequiel Garcia wrote: > > I don't see a good way out that would preserve backwards compatibil= ity, > > other than hardcoding the physical address in the driver, which see= ms > > just as bad as breaking compatibility. That said, it is always the > > same constant (0xf1000000 + 0x20000 + 0x0108) on Dove, Kirkwood and > > Orion5x (not on mv78xx0, but that doesn't use the wdt), so hardcodi= ng > > a fallback would technically work, but we should print a fat warnin= g at > > boot time if we actually fall back to that. > >=20 >=20 > Yes, I was thinking just about this. Namely: >=20 [..] How about something like this? diff --git a/drivers/watchdog/orion_wdt.c b/drivers/watchdog/orion_wdt.= c index a861b88..0014d23 100644 --- a/drivers/watchdog/orion_wdt.c +++ b/drivers/watchdog/orion_wdt.c @@ -26,6 +26,9 @@ #include #include =20 +/* RSTOUT mask register physical address for Orion5x, Kirkwood and Dov= e */ +#define ORION_RSTOUT_MASK 0xf1020108 + /* * Watchdog timer block registers. */ @@ -119,6 +122,30 @@ static irqreturn_t orion_wdt_irq(int irq, void *de= vid) return IRQ_HANDLED; } =20 +/* + * The original devicetree binding for this driver specified only + * one memory resource, so in order to keep DT backwards compatibility + * we try to fallback to a hardcoded register address, if the resource + * is missing from the devicetree. + */ +static void __iomem * try_compat_rstout_ioremap(struct platform_device= *pdev) +{ + struct resource *res; + + res =3D platform_get_resource(pdev, IORESOURCE_MEM, 1); + if (res) + return devm_ioremap(&pdev->dev, res->start, + resource_size(res)); + + /* This workaround works only for "orion-wdt", DT-enabled */ + if (!of_device_is_compatible(pdev->dev.of_node, "marvell,orion-wdt")) + return NULL; + + dev_warn(&pdev->dev, "falling back to harcoded RSTOUT reg 0x%x\n", + ORION_RSTOUT_MASK); + return devm_ioremap(&pdev->dev, ORION_RSTOUT_MASK, 0x4); +} + static int orion_wdt_probe(struct platform_device *pdev) { struct resource *res; @@ -139,10 +166,7 @@ static int orion_wdt_probe(struct platform_device = *pdev) if (!wdt_reg) return -ENOMEM; =20 - res =3D platform_get_resource(pdev, IORESOURCE_MEM, 1); - if (!res) - return -ENODEV; - wdt_rstout =3D devm_ioremap(&pdev->dev, res->start, resource_size(res= )); + wdt_rstout =3D try_compat_rstout_ioremap(pdev); if (!wdt_rstout) return -ENOMEM; =20 --=20 Ezequiel Garc=C3=ADa, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html