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 compatibility, > > other than hardcoding the physical address in the driver, which seems > > 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 hardcoding > > a fallback would technically work, but we should print a fat warning at > > boot time if we actually fall back to that. > > > > Yes, I was thinking just about this. Namely: > [..] 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 <linux/of.h> #include <mach/bridge-regs.h> +/* RSTOUT mask register physical address for Orion5x, Kirkwood and Dove */ +#define ORION_RSTOUT_MASK 0xf1020108 + /* * Watchdog timer block registers. */ @@ -119,6 +122,30 @@ static irqreturn_t orion_wdt_irq(int irq, void *devid) return IRQ_HANDLED; } +/* + * 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 = 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; - res = platform_get_resource(pdev, IORESOURCE_MEM, 1); - if (!res) - return -ENODEV; - wdt_rstout = devm_ioremap(&pdev->dev, res->start, resource_size(res)); + wdt_rstout = try_compat_rstout_ioremap(pdev); if (!wdt_rstout) return -ENOMEM; -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html