From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751194AbdAXQMk (ORCPT ); Tue, 24 Jan 2017 11:12:40 -0500 Received: from mail-it0-f43.google.com ([209.85.214.43]:37585 "EHLO mail-it0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751142AbdAXQMi (ORCPT ); Tue, 24 Jan 2017 11:12:38 -0500 Date: Tue, 24 Jan 2017 09:12:27 -0700 From: Mathieu Poirier To: Baoyou Xie Cc: jun.nie@linaro.org, wim@iguana.be, linux@roeck-us.net, robh+dt@kernel.org, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, shawnguo@kernel.org, xie.baoyou@zte.com.cn, chen.chaokai@zte.com.cn, wang.qiang01@zte.com.cn Subject: Re: [PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family Message-ID: <20170124161227.GA14385@linaro.org> References: <1485248322-24299-1-git-send-email-baoyou.xie@linaro.org> <1485248322-24299-3-git-send-email-baoyou.xie@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1485248322-24299-3-git-send-email-baoyou.xie@linaro.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 24, 2017 at 04:58:42PM +0800, Baoyou Xie wrote: > This patch adds watchdog controller driver for ZTE's zx2967 family. > > Signed-off-by: Baoyou Xie > --- > drivers/watchdog/Kconfig | 10 ++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/zx2967_wdt.c | 274 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 285 insertions(+) > create mode 100644 drivers/watchdog/zx2967_wdt.c > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index acb00b5..05093a2 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -714,6 +714,16 @@ config ASPEED_WATCHDOG > To compile this driver as a module, choose M here: the > module will be called aspeed_wdt. > > +config ZX2967_WATCHDOG > + tristate "ZTE zx2967 SoCs watchdog support" > + depends on ARCH_ZX > + select WATCHDOG_CORE > + help > + Say Y here to include support for the watchdog timer > + in ZTE zx2967 SoCs. > + To compile this driver as a module, choose M here: the > + module will be called zx2967_wdt. > + > # AVR32 Architecture > > config AT32AP700X_WDT > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index 0c3d35e..bf2d296 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -82,6 +82,7 @@ obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o > obj-$(CONFIG_ATLAS7_WATCHDOG) += atlas7_wdt.o > obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o > obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o > +obj-$(CONFIG_ZX2967_WATCHDOG) += zx2967_wdt.o > > # AVR32 Architecture > obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o > diff --git a/drivers/watchdog/zx2967_wdt.c b/drivers/watchdog/zx2967_wdt.c > new file mode 100644 > index 0000000..89a7018 > --- /dev/null > +++ b/drivers/watchdog/zx2967_wdt.c > @@ -0,0 +1,274 @@ > +/* > + * watchdog driver for ZTE's zx2967 family > + * > + * Copyright (C) 2017 ZTE Ltd. > + * > + * Author: Baoyou Xie > + * > + * License terms: GNU General Public License (GPL) version 2 > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define ZX2967_WDT_CFG_REG 0x4 > +#define ZX2967_WDT_LOAD_REG 0x8 > +#define ZX2967_WDT_REFRESH_REG 0x18 > +#define ZX2967_WDT_START_REG 0x1c > + > +#define ZX2967_WDT_REFRESH_MASK 0x3f > + > +#define ZX2967_WDT_CFG_DIV(n) ((((n) & 0xff) - 1) << 8) > +#define ZX2967_WDT_START_EN 0x1 > + > +#define ZX2967_WDT_WRITEKEY 0x12340000 > + > +#define ZX2967_WDT_DIV_DEFAULT 16 > +#define ZX2967_WDT_DEFAULT_TIMEOUT 32 > +#define ZX2967_WDT_MIN_TIMEOUT 1 > +#define ZX2967_WDT_MAX_TIMEOUT 500 > +#define ZX2967_WDT_MAX_COUNT 0xffff > + > +#define ZX2967_WDT_CLK_FREQ 0x8000 > + > +#define ZX2967_WDT_FLAG_REBOOT_MON BIT(0) > + > +struct zx2967_wdt { > + struct watchdog_device wdt_device; > + void __iomem *reg_base; > + struct clk *clock; > +}; > + > +static inline u32 zx2967_wdt_readl(struct zx2967_wdt *wdt, u16 reg) > +{ > + return readl_relaxed(wdt->reg_base + reg); > +} > + > +static inline void zx2967_wdt_writel(struct zx2967_wdt *wdt, u16 reg, u32 val) > +{ > + writel_relaxed(val | ZX2967_WDT_WRITEKEY, wdt->reg_base + reg); > +} > + > +static void zx2967_wdt_refresh(struct zx2967_wdt *wdt) > +{ > + u32 val; > + > + val = zx2967_wdt_readl(wdt, ZX2967_WDT_REFRESH_REG); > + val ^= ZX2967_WDT_REFRESH_MASK; > + zx2967_wdt_writel(wdt, ZX2967_WDT_REFRESH_REG, val); > +} > + > +static int > +zx2967_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout) > +{ > + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); > + unsigned int divisor = ZX2967_WDT_DIV_DEFAULT; > + unsigned int count; > + > + count = timeout * ZX2967_WDT_CLK_FREQ; > + if (count > divisor * ZX2967_WDT_MAX_COUNT) > + divisor = DIV_ROUND_UP(count, ZX2967_WDT_MAX_COUNT); > + count = DIV_ROUND_UP(count, divisor); > + zx2967_wdt_writel(wdt, ZX2967_WDT_CFG_REG, ZX2967_WDT_CFG_DIV(divisor)); > + zx2967_wdt_writel(wdt, ZX2967_WDT_LOAD_REG, count); > + zx2967_wdt_refresh(wdt); > + wdd->timeout = (count * divisor) / ZX2967_WDT_CLK_FREQ; > + > + return 0; > +} > + > +static void __zx2967_wdt_start(struct zx2967_wdt *wdt) > +{ > + u32 val; > + > + val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG); > + val |= ZX2967_WDT_START_EN; > + zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG, val); > +} > + > +static void __zx2967_wdt_stop(struct zx2967_wdt *wdt) > +{ > + u32 val; > + > + val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG); > + val &= ~ZX2967_WDT_START_EN; > + zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG, val); > +} > + > +static int zx2967_wdt_start(struct watchdog_device *wdd) > +{ > + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); > + > + zx2967_wdt_set_timeout(wdd, wdd->timeout); > + __zx2967_wdt_start(wdt); > + > + return 0; > +} > + > +static int zx2967_wdt_stop(struct watchdog_device *wdd) > +{ > + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); > + > + __zx2967_wdt_stop(wdt); > + > + return 0; > +} > + > +static int zx2967_wdt_keepalive(struct watchdog_device *wdd) > +{ > + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); > + > + zx2967_wdt_refresh(wdt); > + > + return 0; > +} > + > +#define ZX2967_WDT_OPTIONS \ > + (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE) > +static const struct watchdog_info zx2967_wdt_ident = { > + .options = ZX2967_WDT_OPTIONS, > + .firmware_version = 0, > + .identity = "zx2967 watchdog", > +}; > + > +static struct watchdog_ops zx2967_wdt_ops = { > + .owner = THIS_MODULE, > + .start = zx2967_wdt_start, > + .stop = zx2967_wdt_stop, > + .ping = zx2967_wdt_keepalive, > + .set_timeout = zx2967_wdt_set_timeout, > +}; > + > +static void zx2967_wdt_reset_sysctrl(struct device *dev) > +{ > + int ret; > + void __iomem *regmap; > + unsigned int offset, mask, config; > + struct of_phandle_args out_args; > + > + ret = of_parse_phandle_with_fixed_args(dev->of_node, > + "zte,wdt-reset-sysctrl", 3, 0, &out_args); Go read the comment I made on your V4 post. > + if (ret) > + return; > + > + offset = out_args.args[0]; > + config = out_args.args[1]; > + mask = out_args.args[2]; > + > + regmap = syscon_node_to_regmap(out_args.np); > + if (IS_ERR(regmap)) > + return; > + > + regmap_update_bits(regmap, offset, mask, config); > +} > + > +static int zx2967_wdt_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct zx2967_wdt *wdt; > + struct resource *base; > + int ret; > + struct reset_control *rstc; > + > + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); > + if (!wdt) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, wdt); > + > + wdt->wdt_device.info = &zx2967_wdt_ident; > + wdt->wdt_device.ops = &zx2967_wdt_ops; > + wdt->wdt_device.timeout = ZX2967_WDT_DEFAULT_TIMEOUT; > + wdt->wdt_device.max_timeout = ZX2967_WDT_MAX_TIMEOUT; > + wdt->wdt_device.min_timeout = ZX2967_WDT_MIN_TIMEOUT; > + wdt->wdt_device.parent = &pdev->dev; > + > + base = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + wdt->reg_base = devm_ioremap_resource(dev, base); > + if (IS_ERR(wdt->reg_base)) { > + dev_err(dev, "ioremap failed\n"); > + return PTR_ERR(wdt->reg_base); > + } > + > + zx2967_wdt_reset_sysctrl(dev); > + > + wdt->clock = devm_clk_get(dev, NULL); > + if (IS_ERR(wdt->clock)) { > + dev_err(dev, "failed to find watchdog clock source\n"); > + return PTR_ERR(wdt->clock); > + } > + > + ret = clk_prepare_enable(wdt->clock); > + if (ret < 0) { > + dev_err(dev, "failed to enable clock\n"); > + return ret; > + } > + clk_set_rate(wdt->clock, ZX2967_WDT_CLK_FREQ); > + > + rstc = devm_reset_control_get(dev, NULL); > + if (IS_ERR(rstc)) { > + dev_err(dev, "failed to get rstc"); > + ret = PTR_ERR(rstc); > + goto fail_get_reset_control; > + } > + > + reset_control_assert(rstc); > + mdelay(10); > + reset_control_deassert(rstc); Still no explanation as to why we need to have a busy loop here. I suggest you take a look at: https://www.kernel.org/doc/Documentation/timers/timers-howto.txt > + > + watchdog_set_drvdata(&wdt->wdt_device, wdt); > + watchdog_set_nowayout(&wdt->wdt_device, WATCHDOG_NOWAYOUT); > + > + ret = watchdog_register_device(&wdt->wdt_device); > + if (ret) > + goto fail_register; > + > + dev_info(dev, "watchdog enabled (timeout=%d sec, nowayout=%d)", > + wdt->wdt_device.timeout, WATCHDOG_NOWAYOUT); > + > + return 0; > + > +fail_register: > + watchdog_unregister_device(&wdt->wdt_device); > +fail_get_reset_control: > + clk_disable_unprepare(wdt->clock); > + return ret; > +} > + > +static int zx2967_wdt_remove(struct platform_device *pdev) > +{ > + struct zx2967_wdt *wdt = platform_get_drvdata(pdev); > + > + watchdog_unregister_device(&wdt->wdt_device); > + clk_disable_unprepare(wdt->clock); > + > + return 0; > +} > + > +static const struct of_device_id zx2967_wdt_match[] = { > + { .compatible = "zte,zx296718-wdt", }, > + {} > +}; > +MODULE_DEVICE_TABLE(of, zx2967_wdt_match); > + > +static struct platform_driver zx2967_wdt_driver = { > + .probe = zx2967_wdt_probe, > + .remove = zx2967_wdt_remove, > + .driver = { > + .name = "zx2967-wdt", > + .of_match_table = of_match_ptr(zx2967_wdt_match), > + }, > +}; > +module_platform_driver(zx2967_wdt_driver); > + > +MODULE_AUTHOR("Baoyou Xie "); > +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver"); > +MODULE_LICENSE("GPL v2"); > -- > 2.7.4 > From mboxrd@z Thu Jan 1 00:00:00 1970 From: mathieu.poirier@linaro.org (Mathieu Poirier) Date: Tue, 24 Jan 2017 09:12:27 -0700 Subject: [PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family In-Reply-To: <1485248322-24299-3-git-send-email-baoyou.xie@linaro.org> References: <1485248322-24299-1-git-send-email-baoyou.xie@linaro.org> <1485248322-24299-3-git-send-email-baoyou.xie@linaro.org> Message-ID: <20170124161227.GA14385@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Jan 24, 2017 at 04:58:42PM +0800, Baoyou Xie wrote: > This patch adds watchdog controller driver for ZTE's zx2967 family. > > Signed-off-by: Baoyou Xie > --- > drivers/watchdog/Kconfig | 10 ++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/zx2967_wdt.c | 274 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 285 insertions(+) > create mode 100644 drivers/watchdog/zx2967_wdt.c > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index acb00b5..05093a2 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -714,6 +714,16 @@ config ASPEED_WATCHDOG > To compile this driver as a module, choose M here: the > module will be called aspeed_wdt. > > +config ZX2967_WATCHDOG > + tristate "ZTE zx2967 SoCs watchdog support" > + depends on ARCH_ZX > + select WATCHDOG_CORE > + help > + Say Y here to include support for the watchdog timer > + in ZTE zx2967 SoCs. > + To compile this driver as a module, choose M here: the > + module will be called zx2967_wdt. > + > # AVR32 Architecture > > config AT32AP700X_WDT > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index 0c3d35e..bf2d296 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -82,6 +82,7 @@ obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o > obj-$(CONFIG_ATLAS7_WATCHDOG) += atlas7_wdt.o > obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o > obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o > +obj-$(CONFIG_ZX2967_WATCHDOG) += zx2967_wdt.o > > # AVR32 Architecture > obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o > diff --git a/drivers/watchdog/zx2967_wdt.c b/drivers/watchdog/zx2967_wdt.c > new file mode 100644 > index 0000000..89a7018 > --- /dev/null > +++ b/drivers/watchdog/zx2967_wdt.c > @@ -0,0 +1,274 @@ > +/* > + * watchdog driver for ZTE's zx2967 family > + * > + * Copyright (C) 2017 ZTE Ltd. > + * > + * Author: Baoyou Xie > + * > + * License terms: GNU General Public License (GPL) version 2 > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define ZX2967_WDT_CFG_REG 0x4 > +#define ZX2967_WDT_LOAD_REG 0x8 > +#define ZX2967_WDT_REFRESH_REG 0x18 > +#define ZX2967_WDT_START_REG 0x1c > + > +#define ZX2967_WDT_REFRESH_MASK 0x3f > + > +#define ZX2967_WDT_CFG_DIV(n) ((((n) & 0xff) - 1) << 8) > +#define ZX2967_WDT_START_EN 0x1 > + > +#define ZX2967_WDT_WRITEKEY 0x12340000 > + > +#define ZX2967_WDT_DIV_DEFAULT 16 > +#define ZX2967_WDT_DEFAULT_TIMEOUT 32 > +#define ZX2967_WDT_MIN_TIMEOUT 1 > +#define ZX2967_WDT_MAX_TIMEOUT 500 > +#define ZX2967_WDT_MAX_COUNT 0xffff > + > +#define ZX2967_WDT_CLK_FREQ 0x8000 > + > +#define ZX2967_WDT_FLAG_REBOOT_MON BIT(0) > + > +struct zx2967_wdt { > + struct watchdog_device wdt_device; > + void __iomem *reg_base; > + struct clk *clock; > +}; > + > +static inline u32 zx2967_wdt_readl(struct zx2967_wdt *wdt, u16 reg) > +{ > + return readl_relaxed(wdt->reg_base + reg); > +} > + > +static inline void zx2967_wdt_writel(struct zx2967_wdt *wdt, u16 reg, u32 val) > +{ > + writel_relaxed(val | ZX2967_WDT_WRITEKEY, wdt->reg_base + reg); > +} > + > +static void zx2967_wdt_refresh(struct zx2967_wdt *wdt) > +{ > + u32 val; > + > + val = zx2967_wdt_readl(wdt, ZX2967_WDT_REFRESH_REG); > + val ^= ZX2967_WDT_REFRESH_MASK; > + zx2967_wdt_writel(wdt, ZX2967_WDT_REFRESH_REG, val); > +} > + > +static int > +zx2967_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout) > +{ > + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); > + unsigned int divisor = ZX2967_WDT_DIV_DEFAULT; > + unsigned int count; > + > + count = timeout * ZX2967_WDT_CLK_FREQ; > + if (count > divisor * ZX2967_WDT_MAX_COUNT) > + divisor = DIV_ROUND_UP(count, ZX2967_WDT_MAX_COUNT); > + count = DIV_ROUND_UP(count, divisor); > + zx2967_wdt_writel(wdt, ZX2967_WDT_CFG_REG, ZX2967_WDT_CFG_DIV(divisor)); > + zx2967_wdt_writel(wdt, ZX2967_WDT_LOAD_REG, count); > + zx2967_wdt_refresh(wdt); > + wdd->timeout = (count * divisor) / ZX2967_WDT_CLK_FREQ; > + > + return 0; > +} > + > +static void __zx2967_wdt_start(struct zx2967_wdt *wdt) > +{ > + u32 val; > + > + val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG); > + val |= ZX2967_WDT_START_EN; > + zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG, val); > +} > + > +static void __zx2967_wdt_stop(struct zx2967_wdt *wdt) > +{ > + u32 val; > + > + val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG); > + val &= ~ZX2967_WDT_START_EN; > + zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG, val); > +} > + > +static int zx2967_wdt_start(struct watchdog_device *wdd) > +{ > + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); > + > + zx2967_wdt_set_timeout(wdd, wdd->timeout); > + __zx2967_wdt_start(wdt); > + > + return 0; > +} > + > +static int zx2967_wdt_stop(struct watchdog_device *wdd) > +{ > + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); > + > + __zx2967_wdt_stop(wdt); > + > + return 0; > +} > + > +static int zx2967_wdt_keepalive(struct watchdog_device *wdd) > +{ > + struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd); > + > + zx2967_wdt_refresh(wdt); > + > + return 0; > +} > + > +#define ZX2967_WDT_OPTIONS \ > + (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE) > +static const struct watchdog_info zx2967_wdt_ident = { > + .options = ZX2967_WDT_OPTIONS, > + .firmware_version = 0, > + .identity = "zx2967 watchdog", > +}; > + > +static struct watchdog_ops zx2967_wdt_ops = { > + .owner = THIS_MODULE, > + .start = zx2967_wdt_start, > + .stop = zx2967_wdt_stop, > + .ping = zx2967_wdt_keepalive, > + .set_timeout = zx2967_wdt_set_timeout, > +}; > + > +static void zx2967_wdt_reset_sysctrl(struct device *dev) > +{ > + int ret; > + void __iomem *regmap; > + unsigned int offset, mask, config; > + struct of_phandle_args out_args; > + > + ret = of_parse_phandle_with_fixed_args(dev->of_node, > + "zte,wdt-reset-sysctrl", 3, 0, &out_args); Go read the comment I made on your V4 post. > + if (ret) > + return; > + > + offset = out_args.args[0]; > + config = out_args.args[1]; > + mask = out_args.args[2]; > + > + regmap = syscon_node_to_regmap(out_args.np); > + if (IS_ERR(regmap)) > + return; > + > + regmap_update_bits(regmap, offset, mask, config); > +} > + > +static int zx2967_wdt_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct zx2967_wdt *wdt; > + struct resource *base; > + int ret; > + struct reset_control *rstc; > + > + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); > + if (!wdt) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, wdt); > + > + wdt->wdt_device.info = &zx2967_wdt_ident; > + wdt->wdt_device.ops = &zx2967_wdt_ops; > + wdt->wdt_device.timeout = ZX2967_WDT_DEFAULT_TIMEOUT; > + wdt->wdt_device.max_timeout = ZX2967_WDT_MAX_TIMEOUT; > + wdt->wdt_device.min_timeout = ZX2967_WDT_MIN_TIMEOUT; > + wdt->wdt_device.parent = &pdev->dev; > + > + base = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + wdt->reg_base = devm_ioremap_resource(dev, base); > + if (IS_ERR(wdt->reg_base)) { > + dev_err(dev, "ioremap failed\n"); > + return PTR_ERR(wdt->reg_base); > + } > + > + zx2967_wdt_reset_sysctrl(dev); > + > + wdt->clock = devm_clk_get(dev, NULL); > + if (IS_ERR(wdt->clock)) { > + dev_err(dev, "failed to find watchdog clock source\n"); > + return PTR_ERR(wdt->clock); > + } > + > + ret = clk_prepare_enable(wdt->clock); > + if (ret < 0) { > + dev_err(dev, "failed to enable clock\n"); > + return ret; > + } > + clk_set_rate(wdt->clock, ZX2967_WDT_CLK_FREQ); > + > + rstc = devm_reset_control_get(dev, NULL); > + if (IS_ERR(rstc)) { > + dev_err(dev, "failed to get rstc"); > + ret = PTR_ERR(rstc); > + goto fail_get_reset_control; > + } > + > + reset_control_assert(rstc); > + mdelay(10); > + reset_control_deassert(rstc); Still no explanation as to why we need to have a busy loop here. I suggest you take a look at: https://www.kernel.org/doc/Documentation/timers/timers-howto.txt > + > + watchdog_set_drvdata(&wdt->wdt_device, wdt); > + watchdog_set_nowayout(&wdt->wdt_device, WATCHDOG_NOWAYOUT); > + > + ret = watchdog_register_device(&wdt->wdt_device); > + if (ret) > + goto fail_register; > + > + dev_info(dev, "watchdog enabled (timeout=%d sec, nowayout=%d)", > + wdt->wdt_device.timeout, WATCHDOG_NOWAYOUT); > + > + return 0; > + > +fail_register: > + watchdog_unregister_device(&wdt->wdt_device); > +fail_get_reset_control: > + clk_disable_unprepare(wdt->clock); > + return ret; > +} > + > +static int zx2967_wdt_remove(struct platform_device *pdev) > +{ > + struct zx2967_wdt *wdt = platform_get_drvdata(pdev); > + > + watchdog_unregister_device(&wdt->wdt_device); > + clk_disable_unprepare(wdt->clock); > + > + return 0; > +} > + > +static const struct of_device_id zx2967_wdt_match[] = { > + { .compatible = "zte,zx296718-wdt", }, > + {} > +}; > +MODULE_DEVICE_TABLE(of, zx2967_wdt_match); > + > +static struct platform_driver zx2967_wdt_driver = { > + .probe = zx2967_wdt_probe, > + .remove = zx2967_wdt_remove, > + .driver = { > + .name = "zx2967-wdt", > + .of_match_table = of_match_ptr(zx2967_wdt_match), > + }, > +}; > +module_platform_driver(zx2967_wdt_driver); > + > +MODULE_AUTHOR("Baoyou Xie "); > +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver"); > +MODULE_LICENSE("GPL v2"); > -- > 2.7.4 >