[PATCHv3] watchdog: add support for the Synopsys DesignWare WDT

On Fri, Jan 7, 2011 at 10:38 PM, Jamie Iles [off-list ref] wrote:

quoted

quoted

+static int dw_wdt_open(struct inode *inode, struct file *filp)
+{
+ ? ? ? /* Make sure we don't get unloaded. */
+ ? ? ? __module_get(THIS_MODULE);
+
+ ? ? ? spin_lock(&dw_wdt.lock);
+ ? ? ? if (!dw_wdt_is_enabled()) {
+ ? ? ? ? ? ? ? /*
+ ? ? ? ? ? ? ? ?* The watchdog is not currently enabled. Set the timeout to
+ ? ? ? ? ? ? ? ?* the maximum and then start it.
+ ? ? ? ? ? ? ? ?*/
+ ? ? ? ? ? ? ? dw_wdt_set_top(DW_WDT_MAX_TOP);

shouldn't we check return value here??

No, dw_wdt_set_top() can't fail, it just returns the timeout period that
it set in seconds. ?We use this when the user changes the timeout period
as we may not be able to select the exact timeout period they chose, but
here we just select the maximum timeout.

Sorry, I missed that.

quoted

quoted

+static int __devinit dw_wdt_drv_probe(struct platform_device *pdev)
+{
+ ? ? ? int ret;
+ ? ? ? struct resource *mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+ ? ? ? if (!mem)
+ ? ? ? ? ? ? ? return -EINVAL;
+
+ ? ? ? if (!devm_request_mem_region(&pdev->dev, mem->start, resource_size(mem),
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?"iomem"))
+ ? ? ? ? ? ? ? return -ENOMEM;
+
+ ? ? ? dw_wdt.regs = devm_ioremap(&pdev->dev, mem->start,
+ ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?resource_size(mem));
+ ? ? ? if (!dw_wdt.regs)
+ ? ? ? ? ? ? ? return -ENOMEM;

should release mem_region in case of error.

quoted

+
+ ? ? ? dw_wdt.clk = clk_get(&pdev->dev, NULL);
+ ? ? ? if (IS_ERR_OR_NULL(dw_wdt.clk))
+ ? ? ? ? ? ? ? return -ENODEV;

should release mem_region and free ioremaped space.

We're using devres for the ioremap and region request so that takes care
of the cleanup for us. ?This also means we don't need to iounmap and
release in the release method.

ok

quoted

Also, may be we can continue here in case of error too.
Some platforms might nor support clock framework. You can enable and
disable clk's if dw_wdt.clk is !NULL

The DesignWare watchdog has 16 timeout periods and these are derived
from the clock frequency input to the WDT. ?If we don't have a clk then
we don't know how long the timeout periods. ?The only alternative would
be to have a 'struct dw_wdt_platform_data' that includes the input clock
frequency which we use if we can't get a clk and get the rate.

That will be fine.

--
viresh