| Message ID | 8b116c77d30013b067676fb2f61744840ef51c32.1495096910.git-series.s.trumtrar@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, 2017-05-18 at 10:42 +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. As these lines are > optional, use devm_reset_control_get_optional_shared. If the reset line > is not specified in the devicetree, the reset framework will just skip > deasserting and continue. > This way all users of the driver will continue to function without > any harm, even if the reset line is not specified in the devicetree. > > 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 | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c > index 914da3a4d334..61cbae3a9331 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 +236,12 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) > goto out_disable_clk; Sorry, I didn't notice this before. > } > > + dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL); > + if (IS_ERR(dw_wdt->rst)) > + return PTR_ERR(dw_wdt->rst); This should either goto out_disable_clk, or the reset_control could be acquired a bit earlier before enabling the clock. > + > + reset_control_deassert(dw_wdt->rst); > + > wdd = &dw_wdt->wdd; > wdd->info = &dw_wdt_ident; > wdd->ops = &dw_wdt_ops; > @@ -278,6 +286,7 @@ static int dw_wdt_drv_remove(struct platform_device *pdev) > { > struct dw_wdt *dw_wdt = platform_get_drvdata(pdev); > > + reset_control_assert(dw_wdt->rst); And I'd move this ... > watchdog_unregister_device(&dw_wdt->wdd); ... here for symmetry. > clk_disable_unprepare(dw_wdt->clk); > Otherwise, Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> regards Philipp
diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c index 914da3a4d334..61cbae3a9331 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 +236,12 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) goto out_disable_clk; } + dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL); + if (IS_ERR(dw_wdt->rst)) + return PTR_ERR(dw_wdt->rst); + + reset_control_deassert(dw_wdt->rst); + wdd = &dw_wdt->wdd; wdd->info = &dw_wdt_ident; wdd->ops = &dw_wdt_ops; @@ -278,6 +286,7 @@ static int dw_wdt_drv_remove(struct platform_device *pdev) { struct dw_wdt *dw_wdt = platform_get_drvdata(pdev); + reset_control_assert(dw_wdt->rst); watchdog_unregister_device(&dw_wdt->wdd); clk_disable_unprepare(dw_wdt->clk);
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. As these lines are optional, use devm_reset_control_get_optional_shared. If the reset line is not specified in the devicetree, the reset framework will just skip deasserting and continue. This way all users of the driver will continue to function without any harm, even if the reset line is not specified in the devicetree. 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 | 9 +++++++++ 1 file changed, 9 insertions(+)