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

[Jamie Iles]

On Fri, Jan 07, 2011 at 04:52:50PM +0000, Russell King - ARM Linux wrote:
> On Fri, Jan 07, 2011 at 10:13:50PM +0530, viresh kumar wrote:
> > > +
> > > +       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.
> > 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
> 
> And some platforms have been known to return NULL for clk_get() as they
> don't support more than one clock.
> 
> arch/arm/mach-aaec2000/core.c:struct clk *clk_get(struct device *dev, const char *id)
> arch/arm/mach-aaec2000/core.c-{
> arch/arm/mach-aaec2000/core.c-  return dev && strcmp(dev_name(dev), "mb:16") ==
> 0 ? NULL : ERR_PTR(-ENOENT);
> --
> arch/arm/mach-at91/at91x40.c:struct clk *clk_get(struct device *dev, const char
> *id)
> arch/arm/mach-at91/at91x40.c-{
> arch/arm/mach-at91/at91x40.c-   return NULL;
> --
> arch/arm/mach-netx/fb.c:struct clk *clk_get(struct device *dev, const char *id)
> arch/arm/mach-netx/fb.c-{
> arch/arm/mach-netx/fb.c-        return dev && strcmp(dev_name(dev), "fb") == 0 ? NULL : ERR_PTR(-ENOENT);
> 
> Please stick to the conventions of the API in the driver.  IS_ERR() values
> mean we failed.  Anything else must be considered success.  Don't assume
> NULL means we failed.

Ok, so I'll change the driver to get the clock rate of the watchdog 
through platform data for those that don't provide a struct clk and 
clk_get_rate() returns 0.

Looking at mach-aaec2000 and mach-netx they don't provide a 
clk_get_rate() which from linux/clk.h doesn't look like it's optional.  
Should these platforms have some kind of stub clk_get_rate()?

Jamie