[PATCH v2 05/15] watchdog: orion: Make RSTOUT register a separate resource
From: Ezequiel Garcia <hidden>
Date: 2014-01-22 18:01:01
Also in:
linux-devicetree, linux-watchdog
Subsystem:
the rest, watchdog device drivers · Maintainers:
Linus Torvalds, Wim Van Sebroeck, Guenter Roeck
Possibly related (same subject, not in this thread)
- 2014-01-22 · Re: [PATCH v2 05/15] watchdog: orion: Make RSTOUT register a separate resource · Ezequiel Garcia <hidden>
- 2014-01-21 · [PATCH v2 05/15] watchdog: orion: Make RSTOUT register a separate resource · Ezequiel Garcia <hidden>
On Wed, Jan 22, 2014 at 01:21:36PM -0300, Ezequiel Garcia wrote:
quoted
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 Garc?a, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com