[PATCH v4 0/2] Add watchdog driver for Sunplus SP7021 SoC

[PATCH v4 0/2] Add watchdog driver for Sunplus SP7021 SoC

[Xiantao Hu]

This is a patch series for watchdog driver for Sunplus SP7021 SoC.

Sunplus SP7021 is an ARM Cortex A7 (4 cores) based SoC. It integrates
many peripherals (ex: UART, I2C, SPI, SDIO, eMMC, USB, SD card and
etc.) into a single chip. It is designed for industrial control.

Refer to:
https://sunplus-tibbo.atlassian.net/wiki/spaces/doc/overview
https://tibbo.com/store/plus1.html

Xiantao Hu (2):
  watchdog: Add Sunplus SP7021 WDT devicetree bindings documentation
  watchdog: Add watchdog driver for Sunplus SP7021

 .../bindings/watchdog/sunplus,sp7021-wdt.yaml |  47 +++
 MAINTAINERS                                   |   7 +
 drivers/watchdog/Kconfig                      |  11 +
 drivers/watchdog/Makefile                     |   1 +
 drivers/watchdog/sunplus_wdt.c                | 278 ++++++++++++++++++
 5 files changed, 344 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
 create mode 100644 drivers/watchdog/sunplus_wdt.c

-- 
2.33.1

[PATCH v4 1/2] watchdog: Add Sunplus SP7021 WDT devicetree bindings documentation

[Xiantao Hu]

This adds the documentation for the devicetree bindings of the Sunplus
SP7021 watchdog driver, found from SP7021 SoCs and newer.

Signed-off-by: Xiantao Hu <xt.hu@cqplus1.com>
---
Changes in v4
 - Fix comments from Mr. Rob Herring

 .../bindings/watchdog/sunplus,sp7021-wdt.yaml | 47 +++++++++++++++++++
 MAINTAINERS                                   |  6 +++
 2 files changed, 53 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml

diff --git a/Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml b/Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
new file mode 100644
index 000000000..9a9bfe150
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
@@ -0,0 +1,47 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) Sunplus Co., Ltd. 2021
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/watchdog/sunplus,sp7021-wdt.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sunplus SoCs Watchdog Device Tree Bindings
+
+maintainers:
+  - XianTao Hu <xt.hu@cqplus1.com>
+
+allOf:
+  - $ref: watchdog.yaml#
+
+properties:
+  compatible:
+    const: sunplus,sp7021-wdt
+
+  reg:
+    items:
+      - description: watchdog registers regions
+      - description: miscellaneous control registers regions
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    watchdog: watchdog@9c000630 {
+        compatible = "sunplus,sp7021-wdt";
+        reg = <0x9c000630 0x08>, <0x9C000274 0x04>;
+        clocks = <&clkc 0x24>;
+        resets = <&rstc 0x14>;
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index fb18ce716..fe6cc971c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18242,6 +18242,12 @@ L:	netdev@vger.kernel.org
 S:	Maintained
 F:	drivers/net/ethernet/dlink/sundance.c
 
+SUNPLUS WATCHDOG DRIVER
+M:	Xiantao Hu <xt.hu@cqplus1.com>
+L:	linux-watchdog@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
+
 SUPERH
 M:	Yoshinori Sato <ysato@users.sourceforge.jp>
 M:	Rich Felker <dalias@libc.org>
-- 
2.33.1

[PATCH v4 2/2] watchdog: Add watchdog driver for Sunplus SP7021

[Xiantao Hu]

Sunplus SP7021 requires watchdog timer support.
Add watchdog driver to enable this.

Signed-off-by: Xiantao Hu <xt.hu@cqplus1.com>
---
Changes in v4
 - Drop the unused varible struct resource *wdt_res.
 - Drop the operations related to address 0x9c000274.
   Put it in bootloader before entry kernel boot in v3.

 MAINTAINERS                    |   1 +
 drivers/watchdog/Kconfig       |  11 ++
 drivers/watchdog/Makefile      |   1 +
 drivers/watchdog/sunplus_wdt.c | 278 +++++++++++++++++++++++++++++++++
 4 files changed, 291 insertions(+)
 create mode 100644 drivers/watchdog/sunplus_wdt.c

diff --git a/MAINTAINERS b/MAINTAINERS
index fe6cc971c..a1b3d76e2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -18247,6 +18247,7 @@ M:	Xiantao Hu <xt.hu@cqplus1.com>
 L:	linux-watchdog@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
+F:	drivers/watchdog/sunplus_wdt.c
 
 SUPERH
 M:	Yoshinori Sato <ysato@users.sourceforge.jp>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 9d222ba17..d3dbe8695 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -976,6 +976,17 @@ config MSC313E_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called msc313e_wdt.
 
+config SUNPLUS_WATCHDOG
+	tristate "Sunplus watchdog support"
+	depends on ARCH_SUNPLUS || COMPILE_TEST
+	select WATCHDOG_CORE
+	help
+	  Say Y here to include support for the watchdog timer
+	  in Sunplus SoCs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called sunplus_wdt.
+
 # X86 (i386 + ia64 + x86_64) Architecture
 
 config ACQUIRE_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 2ee970641..0fa548ee6 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -93,6 +93,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o
 obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o
 obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o
 obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o
+obj-$(CONFIG_SUNPLUS_WATCHDOG) += sunplus_wdt.o
 
 # X86 (i386 + ia64 + x86_64) Architecture
 obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
diff --git a/drivers/watchdog/sunplus_wdt.c b/drivers/watchdog/sunplus_wdt.c
new file mode 100644
index 000000000..9fae7a14b
--- /dev/null
+++ b/drivers/watchdog/sunplus_wdt.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sunplus Watchdog Driver
+ *
+ * Copyright (C) 2021 Sunplus Technology Co., Ltd.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/watchdog.h>
+
+#define WDT_CTRL                0x00
+#define WDT_CNT                 0x04
+
+#define WDT_STOP				0x3877
+#define WDT_RESUME				0x4A4B
+#define WDT_CLRIRQ				0x7482
+#define WDT_UNLOCK				0xAB00
+#define WDT_LOCK				0xAB01
+#define WDT_CONMAX				0xDEAF
+
+#define SP_WDT_MAX_TIMEOUT		11U
+#define SP_WDT_DEFAULT_TIMEOUT	10
+
+#define STC_CLK				90000
+
+#define DEVICE_NAME		"sunplus-wdt"
+
+static unsigned int timeout;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+			__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+struct sp_wdt_priv {
+	struct watchdog_device wdev;
+	void __iomem *base;
+	struct clk *clk;
+	struct reset_control *rstc;
+};
+
+static int sp_wdt_restart(struct watchdog_device *wdev,
+			  unsigned long action, void *data)
+{
+	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+	void __iomem *base = priv->base;
+
+	writel(WDT_STOP, base + WDT_CTRL);
+	writel(WDT_UNLOCK, base + WDT_CTRL);
+	writel(0x0001, base + WDT_CNT);
+	writel(WDT_LOCK, base + WDT_CTRL);
+	writel(WDT_RESUME, base + WDT_CTRL);
+
+	return 0;
+}
+
+/* TIMEOUT_MAX = ffff0/90kHz =11.65,so longer than 11 seconds will time out */
+static int sp_wdt_ping(struct watchdog_device *wdev)
+{
+	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+	void __iomem *base = priv->base;
+	u32 count;
+	u32 actual;
+
+	actual = min(wdev->timeout, SP_WDT_MAX_TIMEOUT);
+
+	if (actual > SP_WDT_MAX_TIMEOUT) {
+		writel(WDT_CONMAX, base + WDT_CTRL);
+	} else {
+		writel(WDT_UNLOCK, base + WDT_CTRL);
+		/* tiemrw_cnt[3:0]can't be write,only [19:4] can be write. */
+		count = (actual * STC_CLK) >> 4;
+		writel(count, base + WDT_CNT);
+		writel(WDT_LOCK, base + WDT_CTRL);
+	}
+
+	return 0;
+}
+
+static int sp_wdt_set_timeout(struct watchdog_device *wdev,
+			      unsigned int timeout)
+{
+	wdev->timeout = timeout;
+	sp_wdt_ping(wdev);
+
+	return 0;
+}
+
+static int sp_wdt_stop(struct watchdog_device *wdev)
+{
+	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+	void __iomem *base = priv->base;
+
+	writel(WDT_STOP, base + WDT_CTRL);
+
+	return 0;
+}
+
+static int sp_wdt_start(struct watchdog_device *wdev)
+{
+	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+	void __iomem *base = priv->base;
+
+	writel(WDT_RESUME, base + WDT_CTRL);
+
+	return 0;
+}
+
+static unsigned int sp_wdt_get_timeleft(struct watchdog_device *wdev)
+{
+	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+	void __iomem *base = priv->base;
+	u32 val;
+
+	val = readl(base + WDT_CNT);
+	val &= 0xffff;
+	val = val << 4;
+
+	return val;
+}
+
+static const struct watchdog_info sp_wdt_info = {
+	.identity	= DEVICE_NAME,
+	.options	= WDIOF_SETTIMEOUT |
+			  WDIOF_MAGICCLOSE |
+			  WDIOF_KEEPALIVEPING,
+};
+
+static const struct watchdog_ops sp_wdt_ops = {
+	.owner		= THIS_MODULE,
+	.start		= sp_wdt_start,
+	.stop		= sp_wdt_stop,
+	.ping		= sp_wdt_ping,
+	.set_timeout	= sp_wdt_set_timeout,
+	.get_timeleft	= sp_wdt_get_timeleft,
+	.restart	= sp_wdt_restart,
+};
+
+static void sp_clk_disable_unprepare(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
+static void sp_reset_control_assert(void *data)
+{
+	reset_control_assert(data);
+}
+
+static int sp_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct sp_wdt_priv *priv;
+	int err;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk)) {
+		dev_err(dev, "Can't find clock source\n");
+		return PTR_ERR(priv->clk);
+	}
+
+	err = clk_prepare_enable(priv->clk);
+	if (err) {
+		dev_err(dev, "Clock can't be enabled correctly\n");
+		return err;
+	}
+
+	/* The timer and watchdog shared the STC reset */
+	priv->rstc = devm_reset_control_get_shared(dev, NULL);
+	if (!IS_ERR(priv->rstc))
+		reset_control_deassert(priv->rstc);
+
+	err = devm_add_action_or_reset(dev, sp_reset_control_assert,
+				       priv->rstc);
+	if (err)
+		return err;
+
+	err = devm_add_action_or_reset(dev, sp_clk_disable_unprepare,
+				       priv->clk);
+	if (err)
+		return err;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->wdev.info = &sp_wdt_info;
+	priv->wdev.ops = &sp_wdt_ops;
+	priv->wdev.timeout = SP_WDT_DEFAULT_TIMEOUT;
+	priv->wdev.max_hw_heartbeat_ms = SP_WDT_MAX_TIMEOUT * 1000;
+	priv->wdev.min_timeout = 1;
+	priv->wdev.parent = dev;
+
+	watchdog_init_timeout(&priv->wdev, timeout, dev);
+	watchdog_set_nowayout(&priv->wdev, nowayout);
+	watchdog_set_restart_priority(&priv->wdev, 128);
+
+	watchdog_set_drvdata(&priv->wdev, priv);
+
+	watchdog_stop_on_reboot(&priv->wdev);
+	err = devm_watchdog_register_device(dev, &priv->wdev);
+	if (err)
+		return err;
+
+	platform_set_drvdata(pdev, priv);
+
+	dev_info(dev, "Watchdog enabled (timeout=%d sec%s.)\n",
+		 priv->wdev.timeout, nowayout ? ", nowayout" : "");
+
+	return 0;
+}
+
+static const struct of_device_id sp_wdt_of_match[] = {
+	{.compatible = "sunplus,sp7021-wdt", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sp_wdt_of_match);
+
+static int __maybe_unused sp_wdt_suspend(struct device *dev)
+{
+	struct sp_wdt_priv *priv = dev_get_drvdata(dev);
+
+	if (watchdog_active(&priv->wdev))
+		sp_wdt_stop(&priv->wdev);
+
+	reset_control_assert(priv->rstc);
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static int __maybe_unused sp_wdt_resume(struct device *dev)
+{
+	int err;
+
+	struct sp_wdt_priv *priv = dev_get_drvdata(dev);
+
+	err = clk_prepare_enable(priv->clk);
+	if (err) {
+		dev_err(dev, "Clock can't be enabled correctly\n");
+		return err;
+	}
+
+	reset_control_deassert(priv->rstc);
+
+	if (watchdog_active(&priv->wdev))
+		sp_wdt_start(&priv->wdev);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(sp_wdt_pm_ops, sp_wdt_suspend, sp_wdt_resume);
+
+static struct platform_driver sp_wdt_driver = {
+	.probe = sp_wdt_probe,
+	.driver = {
+		   .name = DEVICE_NAME,
+		   .of_match_table = sp_wdt_of_match,
+		   .pm = &sp_wdt_pm_ops,
+	},
+};
+
+module_platform_driver(sp_wdt_driver);
+
+MODULE_AUTHOR("Xiantao Hu <xt.hu@cqplus1.com>");
+MODULE_DESCRIPTION("Sunplus Watchdog Timer Driver");
+MODULE_LICENSE("GPL v2");
-- 
2.33.1

Re: [PATCH v4 2/2] watchdog: Add watchdog driver for Sunplus SP7021

[Christophe JAILLET]

Hi,

I spotted some tiny things below while looking for something else in the ML.
So here are my 2c.

CJ

Le 29/12/2021 à 06:43, Xiantao Hu a écrit :
> Sunplus SP7021 requires watchdog timer support.
> Add watchdog driver to enable this.
> 
> Signed-off-by: Xiantao Hu <xt.hu@cqplus1.com>
> ---
> Changes in v4
>   - Drop the unused varible struct resource *wdt_res.
>   - Drop the operations related to address 0x9c000274.
>     Put it in bootloader before entry kernel boot in v3.
> 
>   MAINTAINERS                    |   1 +
>   drivers/watchdog/Kconfig       |  11 ++
>   drivers/watchdog/Makefile      |   1 +
>   drivers/watchdog/sunplus_wdt.c | 278 +++++++++++++++++++++++++++++++++
>   4 files changed, 291 insertions(+)
>   create mode 100644 drivers/watchdog/sunplus_wdt.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fe6cc971c..a1b3d76e2 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -18247,6 +18247,7 @@ M:	Xiantao Hu <xt.hu@cqplus1.com>
>   L:	linux-watchdog@vger.kernel.org
>   S:	Maintained
>   F:	Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
> +F:	drivers/watchdog/sunplus_wdt.c
>   
>   SUPERH
>   M:	Yoshinori Sato <ysato@users.sourceforge.jp>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 9d222ba17..d3dbe8695 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -976,6 +976,17 @@ config MSC313E_WATCHDOG
>   	  To compile this driver as a module, choose M here: the
>   	  module will be called msc313e_wdt.
>   
> +config SUNPLUS_WATCHDOG
> +	tristate "Sunplus watchdog support"
> +	depends on ARCH_SUNPLUS || COMPILE_TEST
> +	select WATCHDOG_CORE
> +	help
> +	  Say Y here to include support for the watchdog timer
> +	  in Sunplus SoCs.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called sunplus_wdt.
> +
>   # X86 (i386 + ia64 + x86_64) Architecture
>   
>   config ACQUIRE_WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 2ee970641..0fa548ee6 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -93,6 +93,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o
>   obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o
>   obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o
>   obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o
> +obj-$(CONFIG_SUNPLUS_WATCHDOG) += sunplus_wdt.o
>   
>   # X86 (i386 + ia64 + x86_64) Architecture
>   obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
> diff --git a/drivers/watchdog/sunplus_wdt.c b/drivers/watchdog/sunplus_wdt.c
> new file mode 100644
> index 000000000..9fae7a14b
> --- /dev/null
> +++ b/drivers/watchdog/sunplus_wdt.c
> @@ -0,0 +1,278 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * sunplus Watchdog Driver
> + *
> + * Copyright (C) 2021 Sunplus Technology Co., Ltd.
> + *
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +#include <linux/watchdog.h>
> +
> +#define WDT_CTRL                0x00
> +#define WDT_CNT                 0x04
> +
> +#define WDT_STOP				0x3877
> +#define WDT_RESUME				0x4A4B
> +#define WDT_CLRIRQ				0x7482
> +#define WDT_UNLOCK				0xAB00
> +#define WDT_LOCK				0xAB01
> +#define WDT_CONMAX				0xDEAF
> +
> +#define SP_WDT_MAX_TIMEOUT		11U
> +#define SP_WDT_DEFAULT_TIMEOUT	10
> +
> +#define STC_CLK				90000
> +
> +#define DEVICE_NAME		"sunplus-wdt"
> +
> +static unsigned int timeout;
> +module_param(timeout, int, 0);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> +			__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +struct sp_wdt_priv {
> +	struct watchdog_device wdev;
> +	void __iomem *base;
> +	struct clk *clk;
> +	struct reset_control *rstc;
> +};
> +
> +static int sp_wdt_restart(struct watchdog_device *wdev,
> +			  unsigned long action, void *data)
> +{
> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	void __iomem *base = priv->base;
> +
> +	writel(WDT_STOP, base + WDT_CTRL);
> +	writel(WDT_UNLOCK, base + WDT_CTRL);
> +	writel(0x0001, base + WDT_CNT);
> +	writel(WDT_LOCK, base + WDT_CTRL);
> +	writel(WDT_RESUME, base + WDT_CTRL);
> +
> +	return 0;
> +}
> +
> +/* TIMEOUT_MAX = ffff0/90kHz =11.65,so longer than 11 seconds will time out */
> +static int sp_wdt_ping(struct watchdog_device *wdev)
> +{
> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	void __iomem *base = priv->base;
> +	u32 count;
> +	u32 actual;
> +
> +	actual = min(wdev->timeout, SP_WDT_MAX_TIMEOUT);
> +
> +	if (actual > SP_WDT_MAX_TIMEOUT) {
> +		writel(WDT_CONMAX, base + WDT_CTRL);
> +	} else {
> +		writel(WDT_UNLOCK, base + WDT_CTRL);
> +		/* tiemrw_cnt[3:0]can't be write,only [19:4] can be write. */
> +		count = (actual * STC_CLK) >> 4;
> +		writel(count, base + WDT_CNT);
> +		writel(WDT_LOCK, base + WDT_CTRL);
> +	}
> +
> +	return 0;
> +}
> +
> +static int sp_wdt_set_timeout(struct watchdog_device *wdev,
> +			      unsigned int timeout)
> +{
> +	wdev->timeout = timeout;
> +	sp_wdt_ping(wdev);
> +
> +	return 0;
> +}
> +
> +static int sp_wdt_stop(struct watchdog_device *wdev)
> +{
> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	void __iomem *base = priv->base;
> +
> +	writel(WDT_STOP, base + WDT_CTRL);
> +
> +	return 0;
> +}
> +
> +static int sp_wdt_start(struct watchdog_device *wdev)
> +{
> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	void __iomem *base = priv->base;
> +
> +	writel(WDT_RESUME, base + WDT_CTRL);
> +
> +	return 0;
> +}
> +
> +static unsigned int sp_wdt_get_timeleft(struct watchdog_device *wdev)
> +{
> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	void __iomem *base = priv->base;
> +	u32 val;
> +
> +	val = readl(base + WDT_CNT);
> +	val &= 0xffff;
> +	val = val << 4;
> +
> +	return val;
> +}
> +
> +static const struct watchdog_info sp_wdt_info = {
> +	.identity	= DEVICE_NAME,
> +	.options	= WDIOF_SETTIMEOUT |
> +			  WDIOF_MAGICCLOSE |
> +			  WDIOF_KEEPALIVEPING,
> +};
> +
> +static const struct watchdog_ops sp_wdt_ops = {
> +	.owner		= THIS_MODULE,
> +	.start		= sp_wdt_start,
> +	.stop		= sp_wdt_stop,
> +	.ping		= sp_wdt_ping,
> +	.set_timeout	= sp_wdt_set_timeout,
> +	.get_timeleft	= sp_wdt_get_timeleft,
> +	.restart	= sp_wdt_restart,
> +};
> +
> +static void sp_clk_disable_unprepare(void *data)
> +{
> +	clk_disable_unprepare(data);
> +}
> +
> +static void sp_reset_control_assert(void *data)
> +{
> +	reset_control_assert(data);
> +}
> +
> +static int sp_wdt_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct sp_wdt_priv *priv;
> +	int err;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(priv->clk)) {
> +		dev_err(dev, "Can't find clock source\n");
> +		return PTR_ERR(priv->clk);
> +	}
> +
> +	err = clk_prepare_enable(priv->clk);
> +	if (err) {
> +		dev_err(dev, "Clock can't be enabled correctly\n");
> +		return err;
> +	}
> +
> +	/* The timer and watchdog shared the STC reset */
> +	priv->rstc = devm_reset_control_get_shared(dev, NULL);
> +	if (!IS_ERR(priv->rstc))
> +		reset_control_deassert(priv->rstc);
> +
> +	err = devm_add_action_or_reset(dev, sp_reset_control_assert,
> +				       priv->rstc);
> +	if (err)
> +		return err;
This looks odd.
We could undo something that was not done. (if IS_ERR(priv->rstc))
This is also not really consistent with what is done in suspedn/resume. 
In these functions, we don't check for IS_ERR(priv->rstc).

> +
> +	err = devm_add_action_or_reset(dev, sp_clk_disable_unprepare,
> +				       priv->clk);
> +	if (err)
> +		return err;
Shouldn't this be just after clk_prepare_enable()?

> +
> +	priv->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(priv->base))
> +		return PTR_ERR(priv->base);
> +
> +	priv->wdev.info = &sp_wdt_info;
> +	priv->wdev.ops = &sp_wdt_ops;
> +	priv->wdev.timeout = SP_WDT_DEFAULT_TIMEOUT;
> +	priv->wdev.max_hw_heartbeat_ms = SP_WDT_MAX_TIMEOUT * 1000;
> +	priv->wdev.min_timeout = 1;
> +	priv->wdev.parent = dev;
> +
> +	watchdog_init_timeout(&priv->wdev, timeout, dev);
> +	watchdog_set_nowayout(&priv->wdev, nowayout);
> +	watchdog_set_restart_priority(&priv->wdev, 128);
> +
> +	watchdog_set_drvdata(&priv->wdev, priv);
> +
> +	watchdog_stop_on_reboot(&priv->wdev);
> +	err = devm_watchdog_register_device(dev, &priv->wdev);
> +	if (err)
> +		return err;
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	dev_info(dev, "Watchdog enabled (timeout=%d sec%s.)\n",
> +		 priv->wdev.timeout, nowayout ? ", nowayout" : "");
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id sp_wdt_of_match[] = {
> +	{.compatible = "sunplus,sp7021-wdt", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, sp_wdt_of_match);
> +
> +static int __maybe_unused sp_wdt_suspend(struct device *dev)
> +{
> +	struct sp_wdt_priv *priv = dev_get_drvdata(dev);
> +
> +	if (watchdog_active(&priv->wdev))
> +		sp_wdt_stop(&priv->wdev);
> +
> +	reset_control_assert(priv->rstc);
> +	clk_disable_unprepare(priv->clk);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused sp_wdt_resume(struct device *dev)
> +{
> +	int err;
> +
> +	struct sp_wdt_priv *priv = dev_get_drvdata(dev);
> +
> +	err = clk_prepare_enable(priv->clk);
> +	if (err) {
> +		dev_err(dev, "Clock can't be enabled correctly\n");
> +		return err;
> +	}
> +
> +	reset_control_deassert(priv->rstc);
> +
> +	if (watchdog_active(&priv->wdev))
> +		sp_wdt_start(&priv->wdev);
> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(sp_wdt_pm_ops, sp_wdt_suspend, sp_wdt_resume);
> +
> +static struct platform_driver sp_wdt_driver = {
> +	.probe = sp_wdt_probe,
> +	.driver = {
> +		   .name = DEVICE_NAME,
> +		   .of_match_table = sp_wdt_of_match,
> +		   .pm = &sp_wdt_pm_ops,
> +	},
> +};
> +
> +module_platform_driver(sp_wdt_driver);
> +
> +MODULE_AUTHOR("Xiantao Hu <xt.hu@cqplus1.com>");
> +MODULE_DESCRIPTION("Sunplus Watchdog Timer Driver");
> +MODULE_LICENSE("GPL v2");
> 

Re: [PATCH v4 2/2] watchdog: Add watchdog driver for Sunplus SP7021

[Guenter Roeck]

On Wed, Dec 29, 2021 at 01:43:08PM +0800, Xiantao Hu wrote:
> Sunplus SP7021 requires watchdog timer support.
> Add watchdog driver to enable this.
> 
> Signed-off-by: Xiantao Hu <xt.hu@cqplus1.com>
> ---
> Changes in v4
>  - Drop the unused varible struct resource *wdt_res.
>  - Drop the operations related to address 0x9c000274.
>    Put it in bootloader before entry kernel boot in v3.
> 
>  MAINTAINERS                    |   1 +
>  drivers/watchdog/Kconfig       |  11 ++
>  drivers/watchdog/Makefile      |   1 +
>  drivers/watchdog/sunplus_wdt.c | 278 +++++++++++++++++++++++++++++++++
>  4 files changed, 291 insertions(+)
>  create mode 100644 drivers/watchdog/sunplus_wdt.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fe6cc971c..a1b3d76e2 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -18247,6 +18247,7 @@ M:	Xiantao Hu <xt.hu@cqplus1.com>
>  L:	linux-watchdog@vger.kernel.org
>  S:	Maintained
>  F:	Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
> +F:	drivers/watchdog/sunplus_wdt.c
>  
>  SUPERH
>  M:	Yoshinori Sato <ysato@users.sourceforge.jp>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 9d222ba17..d3dbe8695 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -976,6 +976,17 @@ config MSC313E_WATCHDOG
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called msc313e_wdt.
>  
> +config SUNPLUS_WATCHDOG
> +	tristate "Sunplus watchdog support"
> +	depends on ARCH_SUNPLUS || COMPILE_TEST
> +	select WATCHDOG_CORE
> +	help
> +	  Say Y here to include support for the watchdog timer
> +	  in Sunplus SoCs.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called sunplus_wdt.
> +
>  # X86 (i386 + ia64 + x86_64) Architecture
>  
>  config ACQUIRE_WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 2ee970641..0fa548ee6 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -93,6 +93,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o
>  obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o
>  obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o
>  obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o
> +obj-$(CONFIG_SUNPLUS_WATCHDOG) += sunplus_wdt.o
>  
>  # X86 (i386 + ia64 + x86_64) Architecture
>  obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
> diff --git a/drivers/watchdog/sunplus_wdt.c b/drivers/watchdog/sunplus_wdt.c
> new file mode 100644
> index 000000000..9fae7a14b
> --- /dev/null
> +++ b/drivers/watchdog/sunplus_wdt.c
> @@ -0,0 +1,278 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * sunplus Watchdog Driver
> + *
> + * Copyright (C) 2021 Sunplus Technology Co., Ltd.
> + *
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +#include <linux/watchdog.h>
> +
> +#define WDT_CTRL                0x00
> +#define WDT_CNT                 0x04
> +
> +#define WDT_STOP				0x3877
> +#define WDT_RESUME				0x4A4B
> +#define WDT_CLRIRQ				0x7482
> +#define WDT_UNLOCK				0xAB00
> +#define WDT_LOCK				0xAB01
> +#define WDT_CONMAX				0xDEAF
> +
> +#define SP_WDT_MAX_TIMEOUT		11U
> +#define SP_WDT_DEFAULT_TIMEOUT	10
> +
> +#define STC_CLK				90000
> +
> +#define DEVICE_NAME		"sunplus-wdt"
> +
> +static unsigned int timeout;
> +module_param(timeout, int, 0);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> +			__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +struct sp_wdt_priv {
> +	struct watchdog_device wdev;
> +	void __iomem *base;
> +	struct clk *clk;
> +	struct reset_control *rstc;
> +};
> +
> +static int sp_wdt_restart(struct watchdog_device *wdev,
> +			  unsigned long action, void *data)
> +{
> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	void __iomem *base = priv->base;
> +
> +	writel(WDT_STOP, base + WDT_CTRL);
> +	writel(WDT_UNLOCK, base + WDT_CTRL);
> +	writel(0x0001, base + WDT_CNT);
> +	writel(WDT_LOCK, base + WDT_CTRL);
> +	writel(WDT_RESUME, base + WDT_CTRL);
> +
> +	return 0;
> +}
> +
> +/* TIMEOUT_MAX = ffff0/90kHz =11.65,so longer than 11 seconds will time out */
> +static int sp_wdt_ping(struct watchdog_device *wdev)
> +{
> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	void __iomem *base = priv->base;
> +	u32 count;
> +	u32 actual;
> +
> +	actual = min(wdev->timeout, SP_WDT_MAX_TIMEOUT);
> +
> +	if (actual > SP_WDT_MAX_TIMEOUT) {
> +		writel(WDT_CONMAX, base + WDT_CTRL);
> +	} else {
> +		writel(WDT_UNLOCK, base + WDT_CTRL);
> +		/* tiemrw_cnt[3:0]can't be write,only [19:4] can be write. */
> +		count = (actual * STC_CLK) >> 4;
> +		writel(count, base + WDT_CNT);
> +		writel(WDT_LOCK, base + WDT_CTRL);
> +	}
> +
> +	return 0;
> +}
> +
> +static int sp_wdt_set_timeout(struct watchdog_device *wdev,
> +			      unsigned int timeout)
> +{
> +	wdev->timeout = timeout;
> +	sp_wdt_ping(wdev);

This is exactly what the calling code does if there is no set_timeout
function, so you can just drop this function,

> +
> +	return 0;
> +}
> +
> +static int sp_wdt_stop(struct watchdog_device *wdev)
> +{
> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	void __iomem *base = priv->base;
> +
> +	writel(WDT_STOP, base + WDT_CTRL);
> +
> +	return 0;
> +}
> +
> +static int sp_wdt_start(struct watchdog_device *wdev)
> +{
> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	void __iomem *base = priv->base;
> +
> +	writel(WDT_RESUME, base + WDT_CTRL);
> +
> +	return 0;
> +}
> +
> +static unsigned int sp_wdt_get_timeleft(struct watchdog_device *wdev)
> +{
> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
> +	void __iomem *base = priv->base;
> +	u32 val;
> +
> +	val = readl(base + WDT_CNT);
> +	val &= 0xffff;
> +	val = val << 4;
> +
> +	return val;
> +}
> +
> +static const struct watchdog_info sp_wdt_info = {
> +	.identity	= DEVICE_NAME,
> +	.options	= WDIOF_SETTIMEOUT |
> +			  WDIOF_MAGICCLOSE |
> +			  WDIOF_KEEPALIVEPING,
> +};
> +
> +static const struct watchdog_ops sp_wdt_ops = {
> +	.owner		= THIS_MODULE,
> +	.start		= sp_wdt_start,
> +	.stop		= sp_wdt_stop,
> +	.ping		= sp_wdt_ping,
> +	.set_timeout	= sp_wdt_set_timeout,
> +	.get_timeleft	= sp_wdt_get_timeleft,
> +	.restart	= sp_wdt_restart,
> +};
> +
> +static void sp_clk_disable_unprepare(void *data)
> +{
> +	clk_disable_unprepare(data);
> +}
> +
> +static void sp_reset_control_assert(void *data)
> +{
> +	reset_control_assert(data);
> +}
> +
> +static int sp_wdt_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct sp_wdt_priv *priv;
> +	int err;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(priv->clk)) {
> +		dev_err(dev, "Can't find clock source\n");
> +		return PTR_ERR(priv->clk);
> +	}
> +
> +	err = clk_prepare_enable(priv->clk);
> +	if (err) {
> +		dev_err(dev, "Clock can't be enabled correctly\n");
> +		return err;
> +	}
> +
> +	/* The timer and watchdog shared the STC reset */
> +	priv->rstc = devm_reset_control_get_shared(dev, NULL);
> +	if (!IS_ERR(priv->rstc))
> +		reset_control_deassert(priv->rstc);
> +
> +	err = devm_add_action_or_reset(dev, sp_reset_control_assert,
> +				       priv->rstc);
> +	if (err)
> +		return err;
> +

devm_add_action_or_reset() above should only be called if 
devm_reset_control_get_shared succeeds.

> +	err = devm_add_action_or_reset(dev, sp_clk_disable_unprepare,
> +				       priv->clk);

This should be called immediately after clk_prepare_enable().

> +	if (err)
> +		return err;
> +
> +	priv->base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(priv->base))
> +		return PTR_ERR(priv->base);
> +
> +	priv->wdev.info = &sp_wdt_info;
> +	priv->wdev.ops = &sp_wdt_ops;
> +	priv->wdev.timeout = SP_WDT_DEFAULT_TIMEOUT;
> +	priv->wdev.max_hw_heartbeat_ms = SP_WDT_MAX_TIMEOUT * 1000;
> +	priv->wdev.min_timeout = 1;
> +	priv->wdev.parent = dev;
> +
> +	watchdog_init_timeout(&priv->wdev, timeout, dev);
> +	watchdog_set_nowayout(&priv->wdev, nowayout);
> +	watchdog_set_restart_priority(&priv->wdev, 128);
> +
> +	watchdog_set_drvdata(&priv->wdev, priv);
> +
> +	watchdog_stop_on_reboot(&priv->wdev);
> +	err = devm_watchdog_register_device(dev, &priv->wdev);
> +	if (err)
> +		return err;
> +
> +	platform_set_drvdata(pdev, priv);
> +
> +	dev_info(dev, "Watchdog enabled (timeout=%d sec%s.)\n",
> +		 priv->wdev.timeout, nowayout ? ", nowayout" : "");
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id sp_wdt_of_match[] = {
> +	{.compatible = "sunplus,sp7021-wdt", },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, sp_wdt_of_match);
> +
> +static int __maybe_unused sp_wdt_suspend(struct device *dev)
> +{
> +	struct sp_wdt_priv *priv = dev_get_drvdata(dev);
> +
> +	if (watchdog_active(&priv->wdev))
> +		sp_wdt_stop(&priv->wdev);
> +
> +	reset_control_assert(priv->rstc);
> +	clk_disable_unprepare(priv->clk);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused sp_wdt_resume(struct device *dev)
> +{
> +	int err;
> +
> +	struct sp_wdt_priv *priv = dev_get_drvdata(dev);
> +
> +	err = clk_prepare_enable(priv->clk);
> +	if (err) {
> +		dev_err(dev, "Clock can't be enabled correctly\n");
> +		return err;
> +	}
> +
> +	reset_control_deassert(priv->rstc);
> +
> +	if (watchdog_active(&priv->wdev))
> +		sp_wdt_start(&priv->wdev);
> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(sp_wdt_pm_ops, sp_wdt_suspend, sp_wdt_resume);
> +
> +static struct platform_driver sp_wdt_driver = {
> +	.probe = sp_wdt_probe,
> +	.driver = {
> +		   .name = DEVICE_NAME,
> +		   .of_match_table = sp_wdt_of_match,
> +		   .pm = &sp_wdt_pm_ops,
> +	},
> +};
> +
> +module_platform_driver(sp_wdt_driver);
> +
> +MODULE_AUTHOR("Xiantao Hu <xt.hu@cqplus1.com>");
> +MODULE_DESCRIPTION("Sunplus Watchdog Timer Driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.33.1
> 

Re: [PATCH v4 2/2] watchdog: Add watchdog driver for Sunplus SP7021

[Christophe JAILLET]

Le 02/01/2022 à 16:00, Guenter Roeck a écrit :
> On Wed, Dec 29, 2021 at 01:43:08PM +0800, Xiantao Hu wrote:
>> Sunplus SP7021 requires watchdog timer support.
>> Add watchdog driver to enable this.
>>
>> Signed-off-by: Xiantao Hu <xt.hu@cqplus1.com>
>> ---
>> Changes in v4
>>   - Drop the unused varible struct resource *wdt_res.
>>   - Drop the operations related to address 0x9c000274.
>>     Put it in bootloader before entry kernel boot in v3.
>>
>>   MAINTAINERS                    |   1 +
>>   drivers/watchdog/Kconfig       |  11 ++
>>   drivers/watchdog/Makefile      |   1 +
>>   drivers/watchdog/sunplus_wdt.c | 278 +++++++++++++++++++++++++++++++++
>>   4 files changed, 291 insertions(+)
>>   create mode 100644 drivers/watchdog/sunplus_wdt.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index fe6cc971c..a1b3d76e2 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -18247,6 +18247,7 @@ M:	Xiantao Hu <xt.hu@cqplus1.com>
>>   L:	linux-watchdog@vger.kernel.org
>>   S:	Maintained
>>   F:	Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
>> +F:	drivers/watchdog/sunplus_wdt.c
>>   
>>   SUPERH
>>   M:	Yoshinori Sato <ysato@users.sourceforge.jp>
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index 9d222ba17..d3dbe8695 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -976,6 +976,17 @@ config MSC313E_WATCHDOG
>>   	  To compile this driver as a module, choose M here: the
>>   	  module will be called msc313e_wdt.
>>   
>> +config SUNPLUS_WATCHDOG
>> +	tristate "Sunplus watchdog support"
>> +	depends on ARCH_SUNPLUS || COMPILE_TEST
>> +	select WATCHDOG_CORE
>> +	help
>> +	  Say Y here to include support for the watchdog timer
>> +	  in Sunplus SoCs.
>> +
>> +	  To compile this driver as a module, choose M here: the
>> +	  module will be called sunplus_wdt.
>> +
>>   # X86 (i386 + ia64 + x86_64) Architecture
>>   
>>   config ACQUIRE_WDT
>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>> index 2ee970641..0fa548ee6 100644
>> --- a/drivers/watchdog/Makefile
>> +++ b/drivers/watchdog/Makefile
>> @@ -93,6 +93,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o
>>   obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o
>>   obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o
>>   obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o
>> +obj-$(CONFIG_SUNPLUS_WATCHDOG) += sunplus_wdt.o
>>   
>>   # X86 (i386 + ia64 + x86_64) Architecture
>>   obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
>> diff --git a/drivers/watchdog/sunplus_wdt.c b/drivers/watchdog/sunplus_wdt.c
>> new file mode 100644
>> index 000000000..9fae7a14b
>> --- /dev/null
>> +++ b/drivers/watchdog/sunplus_wdt.c
>> @@ -0,0 +1,278 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * sunplus Watchdog Driver
>> + *
>> + * Copyright (C) 2021 Sunplus Technology Co., Ltd.
>> + *
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/io.h>
>> +#include <linux/module.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/reset.h>
>> +#include <linux/watchdog.h>
>> +
>> +#define WDT_CTRL                0x00
>> +#define WDT_CNT                 0x04
>> +
>> +#define WDT_STOP				0x3877
>> +#define WDT_RESUME				0x4A4B
>> +#define WDT_CLRIRQ				0x7482
>> +#define WDT_UNLOCK				0xAB00
>> +#define WDT_LOCK				0xAB01
>> +#define WDT_CONMAX				0xDEAF
>> +
>> +#define SP_WDT_MAX_TIMEOUT		11U
>> +#define SP_WDT_DEFAULT_TIMEOUT	10
>> +
>> +#define STC_CLK				90000
>> +
>> +#define DEVICE_NAME		"sunplus-wdt"
>> +
>> +static unsigned int timeout;
>> +module_param(timeout, int, 0);
>> +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
>> +
>> +static bool nowayout = WATCHDOG_NOWAYOUT;
>> +module_param(nowayout, bool, 0);
>> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
>> +			__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
>> +
>> +struct sp_wdt_priv {
>> +	struct watchdog_device wdev;
>> +	void __iomem *base;
>> +	struct clk *clk;
>> +	struct reset_control *rstc;
>> +};
>> +
>> +static int sp_wdt_restart(struct watchdog_device *wdev,
>> +			  unsigned long action, void *data)
>> +{
>> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
>> +	void __iomem *base = priv->base;
>> +
>> +	writel(WDT_STOP, base + WDT_CTRL);
>> +	writel(WDT_UNLOCK, base + WDT_CTRL);
>> +	writel(0x0001, base + WDT_CNT);
>> +	writel(WDT_LOCK, base + WDT_CTRL);
>> +	writel(WDT_RESUME, base + WDT_CTRL);
>> +
>> +	return 0;
>> +}
>> +
>> +/* TIMEOUT_MAX = ffff0/90kHz =11.65,so longer than 11 seconds will time out */
>> +static int sp_wdt_ping(struct watchdog_device *wdev)
>> +{
>> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
>> +	void __iomem *base = priv->base;
>> +	u32 count;
>> +	u32 actual;
>> +
>> +	actual = min(wdev->timeout, SP_WDT_MAX_TIMEOUT);
>> +
>> +	if (actual > SP_WDT_MAX_TIMEOUT) {
>> +		writel(WDT_CONMAX, base + WDT_CTRL);
>> +	} else {
>> +		writel(WDT_UNLOCK, base + WDT_CTRL);
>> +		/* tiemrw_cnt[3:0]can't be write,only [19:4] can be write. */
>> +		count = (actual * STC_CLK) >> 4;
>> +		writel(count, base + WDT_CNT);
>> +		writel(WDT_LOCK, base + WDT_CTRL);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int sp_wdt_set_timeout(struct watchdog_device *wdev,
>> +			      unsigned int timeout)
>> +{
>> +	wdev->timeout = timeout;
>> +	sp_wdt_ping(wdev);
> 
> This is exactly what the calling code does if there is no set_timeout
> function, so you can just drop this function,
> 
>> +
>> +	return 0;
>> +}
>> +
>> +static int sp_wdt_stop(struct watchdog_device *wdev)
>> +{
>> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
>> +	void __iomem *base = priv->base;
>> +
>> +	writel(WDT_STOP, base + WDT_CTRL);
>> +
>> +	return 0;
>> +}
>> +
>> +static int sp_wdt_start(struct watchdog_device *wdev)
>> +{
>> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
>> +	void __iomem *base = priv->base;
>> +
>> +	writel(WDT_RESUME, base + WDT_CTRL);
>> +
>> +	return 0;
>> +}
>> +
>> +static unsigned int sp_wdt_get_timeleft(struct watchdog_device *wdev)
>> +{
>> +	struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
>> +	void __iomem *base = priv->base;
>> +	u32 val;
>> +
>> +	val = readl(base + WDT_CNT);
>> +	val &= 0xffff;
>> +	val = val << 4;
>> +
>> +	return val;
>> +}
>> +
>> +static const struct watchdog_info sp_wdt_info = {
>> +	.identity	= DEVICE_NAME,
>> +	.options	= WDIOF_SETTIMEOUT |
>> +			  WDIOF_MAGICCLOSE |
>> +			  WDIOF_KEEPALIVEPING,
>> +};
>> +
>> +static const struct watchdog_ops sp_wdt_ops = {
>> +	.owner		= THIS_MODULE,
>> +	.start		= sp_wdt_start,
>> +	.stop		= sp_wdt_stop,
>> +	.ping		= sp_wdt_ping,
>> +	.set_timeout	= sp_wdt_set_timeout,
>> +	.get_timeleft	= sp_wdt_get_timeleft,
>> +	.restart	= sp_wdt_restart,
>> +};
>> +
>> +static void sp_clk_disable_unprepare(void *data)
>> +{
>> +	clk_disable_unprepare(data);
>> +}
>> +
>> +static void sp_reset_control_assert(void *data)
>> +{
>> +	reset_control_assert(data);
>> +}
>> +
>> +static int sp_wdt_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct sp_wdt_priv *priv;
>> +	int err;
>> +
>> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>> +	if (!priv)
>> +		return -ENOMEM;
>> +
>> +	priv->clk = devm_clk_get(dev, NULL);
>> +	if (IS_ERR(priv->clk)) {
>> +		dev_err(dev, "Can't find clock source\n");
>> +		return PTR_ERR(priv->clk);
>> +	}
>> +
>> +	err = clk_prepare_enable(priv->clk);
>> +	if (err) {
>> +		dev_err(dev, "Clock can't be enabled correctly\n");
>> +		return err;
>> +	}
>> +
>> +	/* The timer and watchdog shared the STC reset */
>> +	priv->rstc = devm_reset_control_get_shared(dev, NULL);
>> +	if (!IS_ERR(priv->rstc))
>> +		reset_control_deassert(priv->rstc);
>> +
>> +	err = devm_add_action_or_reset(dev, sp_reset_control_assert,
>> +				       priv->rstc);
>> +	if (err)
>> +		return err;
>> +
> 
> devm_add_action_or_reset() above should only be called if
> devm_reset_control_get_shared succeeds.

I also think that the same "if (!IS_ERR(priv->rstc))" should be done in 
the suspend/resume function before calling reset_control_[de]assert()
Otherwise it will WARN.

CJ

> 
>> +	err = devm_add_action_or_reset(dev, sp_clk_disable_unprepare,
>> +				       priv->clk);
> 
> This should be called immediately after clk_prepare_enable().
> 
>> +	if (err)
>> +		return err;
>> +
>> +	priv->base = devm_platform_ioremap_resource(pdev, 0);
>> +	if (IS_ERR(priv->base))
>> +		return PTR_ERR(priv->base);
>> +
>> +	priv->wdev.info = &sp_wdt_info;
>> +	priv->wdev.ops = &sp_wdt_ops;
>> +	priv->wdev.timeout = SP_WDT_DEFAULT_TIMEOUT;
>> +	priv->wdev.max_hw_heartbeat_ms = SP_WDT_MAX_TIMEOUT * 1000;
>> +	priv->wdev.min_timeout = 1;
>> +	priv->wdev.parent = dev;
>> +
>> +	watchdog_init_timeout(&priv->wdev, timeout, dev);
>> +	watchdog_set_nowayout(&priv->wdev, nowayout);
>> +	watchdog_set_restart_priority(&priv->wdev, 128);
>> +
>> +	watchdog_set_drvdata(&priv->wdev, priv);
>> +
>> +	watchdog_stop_on_reboot(&priv->wdev);
>> +	err = devm_watchdog_register_device(dev, &priv->wdev);
>> +	if (err)
>> +		return err;
>> +
>> +	platform_set_drvdata(pdev, priv);
>> +
>> +	dev_info(dev, "Watchdog enabled (timeout=%d sec%s.)\n",
>> +		 priv->wdev.timeout, nowayout ? ", nowayout" : "");
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id sp_wdt_of_match[] = {
>> +	{.compatible = "sunplus,sp7021-wdt", },
>> +	{ /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, sp_wdt_of_match);
>> +
>> +static int __maybe_unused sp_wdt_suspend(struct device *dev)
>> +{
>> +	struct sp_wdt_priv *priv = dev_get_drvdata(dev);
>> +
>> +	if (watchdog_active(&priv->wdev))
>> +		sp_wdt_stop(&priv->wdev);
>> +
>> +	reset_control_assert(priv->rstc);
>> +	clk_disable_unprepare(priv->clk);
>> +
>> +	return 0;
>> +}
>> +
>> +static int __maybe_unused sp_wdt_resume(struct device *dev)
>> +{
>> +	int err;
>> +
>> +	struct sp_wdt_priv *priv = dev_get_drvdata(dev);
>> +
>> +	err = clk_prepare_enable(priv->clk);
>> +	if (err) {
>> +		dev_err(dev, "Clock can't be enabled correctly\n");
>> +		return err;
>> +	}
>> +
>> +	reset_control_deassert(priv->rstc);
>> +
>> +	if (watchdog_active(&priv->wdev))
>> +		sp_wdt_start(&priv->wdev);
>> +
>> +	return 0;
>> +}
>> +
>> +static SIMPLE_DEV_PM_OPS(sp_wdt_pm_ops, sp_wdt_suspend, sp_wdt_resume);
>> +
>> +static struct platform_driver sp_wdt_driver = {
>> +	.probe = sp_wdt_probe,
>> +	.driver = {
>> +		   .name = DEVICE_NAME,
>> +		   .of_match_table = sp_wdt_of_match,
>> +		   .pm = &sp_wdt_pm_ops,
>> +	},
>> +};
>> +
>> +module_platform_driver(sp_wdt_driver);
>> +
>> +MODULE_AUTHOR("Xiantao Hu <xt.hu@cqplus1.com>");
>> +MODULE_DESCRIPTION("Sunplus Watchdog Timer Driver");
>> +MODULE_LICENSE("GPL v2");
>> -- 
>> 2.33.1
>>
> 

RE: [PATCH v4 2/2] watchdog: Add watchdog driver for Sunplus SP7021

[xt.hu[胡先韬]]

> -----Original Message-----
> From: Guenter Roeck [mailto:groeck7@gmail.com] On Behalf Of Guenter Roeck
> Sent: Sunday, January 2, 2022 11:00 PM
> To: xt.hu[胡先韬] <xt.hu@cqplus1.com>
> Cc: wim@linux-watchdog.org; p.zabel@pengutronix.de; linux-kernel@vger.kernel.org;
> linux-watchdog@vger.kernel.org; robh+dt@kernel.org; devicetree@vger.kernel.org; Wells Lu 呂芳騰
> <wells.lu@sunplus.com>; qinjian[覃健] <qinjian@cqplus1.com>
> Subject: Re: [PATCH v4 2/2] watchdog: Add watchdog driver for Sunplus SP7021
> 
> On Wed, Dec 29, 2021 at 01:43:08PM +0800, Xiantao Hu wrote:
> > Sunplus SP7021 requires watchdog timer support.
> > Add watchdog driver to enable this.
> >
> > Signed-off-by: Xiantao Hu <xt.hu@cqplus1.com>
> > ---
> > Changes in v4
> >  - Drop the unused varible struct resource *wdt_res.
> >  - Drop the operations related to address 0x9c000274.
> >    Put it in bootloader before entry kernel boot in v3.
> >
> >...
> > +{
> > +	wdev->timeout = timeout;
> > +	sp_wdt_ping(wdev);
> 
> This is exactly what the calling code does if there is no set_timeout
> function, so you can just drop this function,
> 

OK. I will drop it.

> > ...
> > +
> > +	err = clk_prepare_enable(priv->clk);
> > +	if (err) {
> > +		dev_err(dev, "Clock can't be enabled correctly\n");
> > +		return err;
> > +	}
> > +
> > +	/* The timer and watchdog shared the STC reset */
> > +	priv->rstc = devm_reset_control_get_shared(dev, NULL);
> > +	if (!IS_ERR(priv->rstc))
> > +		reset_control_deassert(priv->rstc);
> > +
> > +	err = devm_add_action_or_reset(dev, sp_reset_control_assert,
> > +				       priv->rstc);
> > +	if (err)
> > +		return err;
> > +
> 
> devm_add_action_or_reset() above should only be called if
> devm_reset_control_get_shared succeeds.
> 

OK. I will modify it.

> > +	err = devm_add_action_or_reset(dev, sp_clk_disable_unprepare,
> > +				       priv->clk);
> 
> This should be called immediately after clk_prepare_enable().
> 

OK. I will modify it.

> > +	if (err)
> > +		return err;
> > ...

Re: [PATCH v4 1/2] watchdog: Add Sunplus SP7021 WDT devicetree bindings documentation

[Rob Herring]

On Wed, 29 Dec 2021 13:43:07 +0800, Xiantao Hu wrote:
> This adds the documentation for the devicetree bindings of the Sunplus
> SP7021 watchdog driver, found from SP7021 SoCs and newer.
> 
> Signed-off-by: Xiantao Hu <xt.hu@cqplus1.com>
> ---
> Changes in v4
>  - Fix comments from Mr. Rob Herring
> 
>  .../bindings/watchdog/sunplus,sp7021-wdt.yaml | 47 +++++++++++++++++++
>  MAINTAINERS                                   |  6 +++
>  2 files changed, 53 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/sunplus,sp7021-wdt.yaml
> 

Reviewed-by: Rob Herring <robh@kernel.org>