| Message ID | 20200526154123.24402-6-Sergey.Semin@baikalelectronics.ru (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | watchdog: dw_wdt: Take Baikal-T1 DW WDT peculiarities into account | expand |
On Tue, May 26, 2020 at 06:41:21PM +0300, Serge Semin wrote: > DW Watchdog IP core can be synthesised with asynchronous timer/APB > clocks support (WDT_ASYNC_CLK_MODE_ENABLE == 1). In this case > separate clock signals are supposed to be used to feed watchdog timer > and APB interface of the device. Currently the driver supports > the synchronous mode only. Since there is no way to determine which > mode was actually activated for device from its registers, we have to > rely on the platform device configuration data. If optional "pclk" > clock source is supplied, we consider the device working in asynchronous > mode, otherwise the driver falls back to the synchronous configuration. > > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> > Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> > Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Rob Herring <robh+dt@kernel.org> > Cc: linux-mips@vger.kernel.org > Cc: devicetree@vger.kernel.org Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > > Changelog v2: > - Rearrange SoBs. > --- > drivers/watchdog/dw_wdt.c | 48 +++++++++++++++++++++++++++++++++++---- > 1 file changed, 43 insertions(+), 5 deletions(-) > > diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c > index 693c0d1fd796..efbc36872670 100644 > --- a/drivers/watchdog/dw_wdt.c > +++ b/drivers/watchdog/dw_wdt.c > @@ -68,6 +68,7 @@ struct dw_wdt_timeout { > struct dw_wdt { > void __iomem *regs; > struct clk *clk; > + struct clk *pclk; > unsigned long rate; > struct dw_wdt_timeout timeouts[DW_WDT_NUM_TOPS]; > struct watchdog_device wdd; > @@ -274,6 +275,7 @@ static int dw_wdt_suspend(struct device *dev) > dw_wdt->control = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); > dw_wdt->timeout = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); > > + clk_disable_unprepare(dw_wdt->pclk); > clk_disable_unprepare(dw_wdt->clk); > > return 0; > @@ -287,6 +289,12 @@ static int dw_wdt_resume(struct device *dev) > if (err) > return err; > > + err = clk_prepare_enable(dw_wdt->pclk); > + if (err) { > + clk_disable_unprepare(dw_wdt->clk); > + return err; > + } > + > writel(dw_wdt->timeout, dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); > writel(dw_wdt->control, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); > > @@ -393,9 +401,18 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) > if (IS_ERR(dw_wdt->regs)) > return PTR_ERR(dw_wdt->regs); > > - dw_wdt->clk = devm_clk_get(dev, NULL); > - if (IS_ERR(dw_wdt->clk)) > - return PTR_ERR(dw_wdt->clk); > + /* > + * Try to request the watchdog dedicated timer clock source. It must > + * be supplied if asynchronous mode is enabled. Otherwise fallback > + * to the common timer/bus clocks configuration, in which the very > + * first found clock supply both timer and APB signals. > + */ > + dw_wdt->clk = devm_clk_get(dev, "tclk"); > + if (IS_ERR(dw_wdt->clk)) { > + dw_wdt->clk = devm_clk_get(dev, NULL); > + if (IS_ERR(dw_wdt->clk)) > + return PTR_ERR(dw_wdt->clk); > + } > > ret = clk_prepare_enable(dw_wdt->clk); > if (ret) > @@ -407,10 +424,27 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) > goto out_disable_clk; > } > > + /* > + * Request APB clock if device is configured with async clocks mode. > + * In this case both tclk and pclk clocks are supposed to be specified. > + * Alas we can't know for sure whether async mode was really activated, > + * so the pclk phandle reference is left optional. If it couldn't be > + * found we consider the device configured in synchronous clocks mode. > + */ > + dw_wdt->pclk = devm_clk_get_optional(dev, "pclk"); > + if (IS_ERR(dw_wdt->pclk)) { > + ret = PTR_ERR(dw_wdt->pclk); > + goto out_disable_clk; > + } > + > + ret = clk_prepare_enable(dw_wdt->pclk); > + if (ret) > + goto out_disable_clk; > + > dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL); > if (IS_ERR(dw_wdt->rst)) { > ret = PTR_ERR(dw_wdt->rst); > - goto out_disable_clk; > + goto out_disable_pclk; > } > > reset_control_deassert(dw_wdt->rst); > @@ -449,10 +483,13 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) > > ret = watchdog_register_device(wdd); > if (ret) > - goto out_disable_clk; > + goto out_disable_pclk; > > return 0; > > +out_disable_pclk: > + clk_disable_unprepare(dw_wdt->pclk); > + > out_disable_clk: > clk_disable_unprepare(dw_wdt->clk); > return ret; > @@ -464,6 +501,7 @@ static int dw_wdt_drv_remove(struct platform_device *pdev) > > watchdog_unregister_device(&dw_wdt->wdd); > reset_control_assert(dw_wdt->rst); > + clk_disable_unprepare(dw_wdt->pclk); > clk_disable_unprepare(dw_wdt->clk); > > return 0;
diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c index 693c0d1fd796..efbc36872670 100644 --- a/drivers/watchdog/dw_wdt.c +++ b/drivers/watchdog/dw_wdt.c @@ -68,6 +68,7 @@ struct dw_wdt_timeout { struct dw_wdt { void __iomem *regs; struct clk *clk; + struct clk *pclk; unsigned long rate; struct dw_wdt_timeout timeouts[DW_WDT_NUM_TOPS]; struct watchdog_device wdd; @@ -274,6 +275,7 @@ static int dw_wdt_suspend(struct device *dev) dw_wdt->control = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); dw_wdt->timeout = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); + clk_disable_unprepare(dw_wdt->pclk); clk_disable_unprepare(dw_wdt->clk); return 0; @@ -287,6 +289,12 @@ static int dw_wdt_resume(struct device *dev) if (err) return err; + err = clk_prepare_enable(dw_wdt->pclk); + if (err) { + clk_disable_unprepare(dw_wdt->clk); + return err; + } + writel(dw_wdt->timeout, dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET); writel(dw_wdt->control, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); @@ -393,9 +401,18 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) if (IS_ERR(dw_wdt->regs)) return PTR_ERR(dw_wdt->regs); - dw_wdt->clk = devm_clk_get(dev, NULL); - if (IS_ERR(dw_wdt->clk)) - return PTR_ERR(dw_wdt->clk); + /* + * Try to request the watchdog dedicated timer clock source. It must + * be supplied if asynchronous mode is enabled. Otherwise fallback + * to the common timer/bus clocks configuration, in which the very + * first found clock supply both timer and APB signals. + */ + dw_wdt->clk = devm_clk_get(dev, "tclk"); + if (IS_ERR(dw_wdt->clk)) { + dw_wdt->clk = devm_clk_get(dev, NULL); + if (IS_ERR(dw_wdt->clk)) + return PTR_ERR(dw_wdt->clk); + } ret = clk_prepare_enable(dw_wdt->clk); if (ret) @@ -407,10 +424,27 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) goto out_disable_clk; } + /* + * Request APB clock if device is configured with async clocks mode. + * In this case both tclk and pclk clocks are supposed to be specified. + * Alas we can't know for sure whether async mode was really activated, + * so the pclk phandle reference is left optional. If it couldn't be + * found we consider the device configured in synchronous clocks mode. + */ + dw_wdt->pclk = devm_clk_get_optional(dev, "pclk"); + if (IS_ERR(dw_wdt->pclk)) { + ret = PTR_ERR(dw_wdt->pclk); + goto out_disable_clk; + } + + ret = clk_prepare_enable(dw_wdt->pclk); + if (ret) + goto out_disable_clk; + dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL); if (IS_ERR(dw_wdt->rst)) { ret = PTR_ERR(dw_wdt->rst); - goto out_disable_clk; + goto out_disable_pclk; } reset_control_deassert(dw_wdt->rst); @@ -449,10 +483,13 @@ static int dw_wdt_drv_probe(struct platform_device *pdev) ret = watchdog_register_device(wdd); if (ret) - goto out_disable_clk; + goto out_disable_pclk; return 0; +out_disable_pclk: + clk_disable_unprepare(dw_wdt->pclk); + out_disable_clk: clk_disable_unprepare(dw_wdt->clk); return ret; @@ -464,6 +501,7 @@ static int dw_wdt_drv_remove(struct platform_device *pdev) watchdog_unregister_device(&dw_wdt->wdd); reset_control_assert(dw_wdt->rst); + clk_disable_unprepare(dw_wdt->pclk); clk_disable_unprepare(dw_wdt->clk); return 0;
DW Watchdog IP core can be synthesised with asynchronous timer/APB clocks support (WDT_ASYNC_CLK_MODE_ENABLE == 1). In this case separate clock signals are supposed to be used to feed watchdog timer and APB interface of the device. Currently the driver supports the synchronous mode only. Since there is no way to determine which mode was actually activated for device from its registers, we have to rely on the platform device configuration data. If optional "pclk" clock source is supplied, we consider the device working in asynchronous mode, otherwise the driver falls back to the synchronous configuration. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org --- Changelog v2: - Rearrange SoBs. --- drivers/watchdog/dw_wdt.c | 48 +++++++++++++++++++++++++++++++++++---- 1 file changed, 43 insertions(+), 5 deletions(-)