| Message ID | 44e4e733055cfa2ed79091542c7bb17aa24afca9.1494595189.git-series.s.trumtrar@pengutronix.de |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On 05/12/2017 06:34 AM, Steffen Trumtrar wrote: > The dw_wdt has an external reset line, that can keep the device in reset > and therefore rendering it useless and also is the only way of stopping > the watchdog once it was started. > > Get the reset lines for this core from the devicetree. > If resets are not specified just warn but don't fail probing to be compatible > with all users. > > Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de> > Cc: Wim Van Sebroeck <wim@iguana.be> > Cc: Guenter Roeck <linux@roeck-us.net> > Cc: linux-watchdog@vger.kernel.org > --- > drivers/watchdog/dw_wdt.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c > index 914da3a4d334..3accddf1f381 100644 > --- a/drivers/watchdog/dw_wdt.c > +++ b/drivers/watchdog/dw_wdt.c > @@ -29,6 +29,7 @@ > #include <linux/of.h> > #include <linux/pm.h> > #include <linux/platform_device.h> > +#include <linux/reset.h> > #include <linux/watchdog.h> > > #define WDOG_CONTROL_REG_OFFSET 0x00 > @@ -54,6 +55,7 @@ struct dw_wdt { > struct clk *clk; > unsigned long rate; > struct watchdog_device wdd; > + struct reset_control *rst; > }; > > #define to_dw_wdt(wdd) container_of(wdd, struct dw_wdt, wdd) > @@ -234,6 +236,8 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) > goto out_disable_clk; > } > > + dw_wdt->rst = devm_reset_control_get(&pdev->dev, NULL); > + devm_reset_control_get() does not return NULL, it returns ERR_PTR on error. > wdd = &dw_wdt->wdd; > wdd->info = &dw_wdt_ident; > wdd->ops = &dw_wdt_ops; > @@ -267,6 +271,9 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) > if (ret) > goto out_disable_clk; > > + if (dw_wdt->rst) > + reset_control_deassert(dw_wdt->rst); Granted, this doesn't cause a crash here, but a warning with traceback. Either case, the if() statement misses the point. > + > return 0; > > out_disable_clk: > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, May 12, 2017 at 03:34:35PM +0200, Steffen Trumtrar wrote: > Document the reset lines holding the watchdog core in reset. > > Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de> > Cc: Wim Van Sebroeck <wim@iguana.be> > Cc: Rob Herring <robh+dt@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: linux-watchdog@vger.kernel.org > Cc: devicetree@vger.kernel.org > --- > Documentation/devicetree/bindings/watchdog/dw_wdt.txt | 3 +++ > 1 file changed, 3 insertions(+) Acked-by: Rob Herring <robh@kernel.org> -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Steffen, On Fri, 2017-05-12 at 15:34 +0200, Steffen Trumtrar wrote: > The dw_wdt has an external reset line, that can keep the device in reset > and therefore rendering it useless and also is the only way of stopping > the watchdog once it was started. > > Get the reset lines for this core from the devicetree. > If resets are not specified just warn but don't fail probing to be compatible > with all users. > > Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de> > Cc: Wim Van Sebroeck <wim@iguana.be> > Cc: Guenter Roeck <linux@roeck-us.net> > Cc: linux-watchdog@vger.kernel.org > --- > drivers/watchdog/dw_wdt.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c > index 914da3a4d334..3accddf1f381 100644 > --- a/drivers/watchdog/dw_wdt.c > +++ b/drivers/watchdog/dw_wdt.c > @@ -29,6 +29,7 @@ > #include <linux/of.h> > #include <linux/pm.h> > #include <linux/platform_device.h> > +#include <linux/reset.h> > #include <linux/watchdog.h> > > #define WDOG_CONTROL_REG_OFFSET 0x00 > @@ -54,6 +55,7 @@ struct dw_wdt { > struct clk *clk; > unsigned long rate; > struct watchdog_device wdd; > + struct reset_control *rst; > }; > > #define to_dw_wdt(wdd) container_of(wdd, struct dw_wdt, wdd) > @@ -234,6 +236,8 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) > goto out_disable_clk; > } > > + dw_wdt->rst = devm_reset_control_get(&pdev->dev, NULL); > + This should be dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL); if (IS_ERR(dw_wdt->rst)) return PTR_ERR(dw_wdt->rst); The optional variants return NULL if the reset is not specified in the DT. > wdd = &dw_wdt->wdd; > wdd->info = &dw_wdt_ident; > wdd->ops = &dw_wdt_ops; > @@ -267,6 +271,9 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) > if (ret) > goto out_disable_clk; > > + if (dw_wdt->rst) > + reset_control_deassert(dw_wdt->rst); > + This can be changed to reset_control_deassert(dw_wdt->rst); > return 0; > > out_disable_clk: Consider adding a call to reset_control_assert() in dw_wdt_drv_remove. regards Philipp -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/devicetree/bindings/watchdog/dw_wdt.txt b/Documentation/devicetree/bindings/watchdog/dw_wdt.txt index 08e16f684f2d..eb0914420c7c 100644 --- a/Documentation/devicetree/bindings/watchdog/dw_wdt.txt +++ b/Documentation/devicetree/bindings/watchdog/dw_wdt.txt @@ -10,6 +10,8 @@ Required Properties: Optional Properties: - interrupts : The interrupt used for the watchdog timeout warning. +- resets : phandle pointing to the system reset controller with + line index for the watchdog. Example: @@ -18,4 +20,5 @@ Example: reg = <0xffd02000 0x1000>; interrupts = <0 171 4>; clocks = <&per_base_clk>; + resets = <&rst WDT0_RESET>; };
Document the reset lines holding the watchdog core in reset. Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de> Cc: Wim Van Sebroeck <wim@iguana.be> Cc: Rob Herring <robh+dt@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: linux-watchdog@vger.kernel.org Cc: devicetree@vger.kernel.org --- Documentation/devicetree/bindings/watchdog/dw_wdt.txt | 3 +++ 1 file changed, 3 insertions(+)