[PATCH v1 1/3] dt: bindings: add documentation for zx2967 family watchdog controller

[PATCH v1 1/3] dt: bindings: add documentation for zx2967 family watchdog controller

[Baoyou Xie]

This patch adds dt-binding documentation for zx2967 family
watchdog controller.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
---
 .../bindings/watchdog/zte,zx2967-wdt.txt           | 29 ++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt

diff --git a/Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt b/Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt
new file mode 100644
index 0000000..0fe0d40
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt
@@ -0,0 +1,29 @@
+ZTE zx2967 Watchdog timer
+
+Required properties:
+
+- compatible : should be one of the following.
+       * zte,zx296718-wdt
+- reg : Specifies base physical address and size of the registers.
+- clocks : Pairs of phandle and specifier referencing the controller's clocks.
+- clock-names: "wdtclk" for the watchdog clock.
+- resets : Reference to the reset controller controlling the watchdog
+           controller.
+- reset-names : Must include the following entries:
+       * wdtrst
+
+Optional properties:
+
+- reset-mask-config : Mask and configuare value that be wrote to aon-sysctrl.
+
+Example:
+
+wdt_ares: watchdog@1465000 {
+	compatible = "zte,zx296718-wdt";
+	reg = <0x1465000 0x1000>;
+	clocks = <&topcrm WDT_WCLK>;
+	clock-names = "wdtclk";
+	resets = <&toprst 35>;
+	reset-names = "wdtrst";
+	reset-mask-config = <1 0x115>;
+};
-- 
2.7.4

[PATCH v1 2/3] MAINTAINERS: add zx2967 watchdog controller driver to ARM ZTE architecture

[Baoyou Xie]

Add the zx2967 watchdog controller driver as maintained by ARM ZTE
architecture maintainers, as they're parts of the core IP.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
---
 MAINTAINERS | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 08f8155..77f0290 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1983,11 +1983,13 @@ F:	drivers/clk/zte/
 F:	drivers/reset/reset-zx2967.c
 F:	drivers/soc/zte/
 F:	drivers/thermal/zx*
+F:	drivers/watchdog/zx2967_wdt.c
 F:	Documentation/devicetree/bindings/arm/zte.txt
 F:	Documentation/devicetree/bindings/clock/zx296702-clk.txt
 F:	Documentation/devicetree/bindings/reset/zte,zx2967-reset.txt
 F:	Documentation/devicetree/bindings/soc/zte/
 F:	Documentation/devicetree/bindings/thermal/zx*
+F:	Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt
 F:	include/dt-bindings/soc/zx*.h
 
 ARM/ZYNQ ARCHITECTURE
-- 
2.7.4

[PATCH v1 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Baoyou Xie]

This patch adds watchdog controller driver for ZTE's zx2967 family.

Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
---
 drivers/watchdog/Kconfig      |  10 ++
 drivers/watchdog/Makefile     |   1 +
 drivers/watchdog/zx2967_wdt.c | 405 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 416 insertions(+)
 create mode 100644 drivers/watchdog/zx2967_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 3eb58cb..79027da 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 caa9f4a..ea08925 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..8791dd2
--- /dev/null
+++ b/drivers/watchdog/zx2967_wdt.c
@@ -0,0 +1,405 @@
+/*
+ * watchdog driver for ZTE's zx2967 family
+ *
+ * Copyright (C) 2017 ZTE Ltd.
+ *
+ * Author: Baoyou Xie <baoyou.xie@linaro.org>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/reset.h>
+#include <linux/watchdog.h>
+
+#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_FLAG_REBOOT_MON		(1 << 0)
+
+#define ZX2967_RESET_MASK_REG			0xb0
+
+#define zx2967_wdt_write_reg(v, r) \
+			writel((v) | ZX2967_WDT_WRITEKEY, r)
+#define zx2967_wdt_read_reg(r)			readl(r)
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+static unsigned int timeout = ZX2967_WDT_DEFAULT_TIMEOUT;
+
+struct zx2967_wdt {
+	struct device		*dev;
+	struct clk		*clock;
+	void __iomem		*reg_base;
+	unsigned int		conf;
+	unsigned int		load;
+	unsigned int		flags;
+	spinlock_t		lock;
+	struct watchdog_device	wdt_device;
+	struct notifier_block	restart_handler;
+	struct notifier_block	reboot_handler;
+};
+
+static void zx2967_wdt_refresh(struct zx2967_wdt *wdt)
+{
+	unsigned int val;
+
+	spin_lock(&wdt->lock);
+
+	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_REFRESH_REG);
+	val ^= ZX2967_WDT_REFRESH_MASK;
+	zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_REFRESH_REG);
+
+	spin_unlock(&wdt->lock);
+}
+
+static void __zx2967_wdt_stop(struct zx2967_wdt *wdt)
+{
+	unsigned int val;
+
+	spin_lock(&wdt->lock);
+
+	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
+	val &= ~(ZX2967_WDT_START_EN);
+	zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_START_REG);
+
+	spin_unlock(&wdt->lock);
+}
+
+static void __zx2967_wdt_start(struct zx2967_wdt *wdt)
+{
+	unsigned int val;
+
+	spin_lock(&wdt->lock);
+
+	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
+	val |= ZX2967_WDT_START_EN;
+	zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_START_REG);
+
+	spin_unlock(&wdt->lock);
+}
+
+static unsigned int
+__zx2967_wdt_set_timeout(struct zx2967_wdt *wdt, unsigned int timeout)
+{
+	unsigned int freq = clk_get_rate(wdt->clock);
+	unsigned int divisor = ZX2967_WDT_DIV_DEFAULT, count;
+
+	count = timeout * 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_write_reg(ZX2967_WDT_CFG_DIV(divisor),
+			     wdt->reg_base + ZX2967_WDT_CFG_REG);
+	zx2967_wdt_write_reg(count, wdt->reg_base + ZX2967_WDT_LOAD_REG);
+	zx2967_wdt_refresh(wdt);
+
+	wdt->load = count;
+	dev_info(wdt->dev, "count=%d, timeout=%d, divisor=%d\n",
+		 count, timeout, divisor);
+
+	return (count * divisor) / freq;
+}
+
+static int zx2967_wdt_set_timeout(struct watchdog_device *wdd,
+				  unsigned int timeout)
+{
+	struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
+
+	if (watchdog_timeout_invalid(&wdt->wdt_device, timeout)) {
+		dev_err(wdt->dev, "timeout %d is invalid\n", timeout);
+
+		return -EINVAL;
+	}
+
+	wdd->timeout = __zx2967_wdt_set_timeout(wdt, timeout);
+
+	return 0;
+}
+
+static int zx2967_wdt_start(struct watchdog_device *wdd)
+{
+	struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
+
+	__zx2967_wdt_stop(wdt);
+	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_fix_sysdown(struct zx2967_wdt *wdt)
+{
+	__zx2967_wdt_stop(wdt);
+	__zx2967_wdt_set_timeout(wdt, 15);
+	__zx2967_wdt_start(wdt);
+}
+
+static int zx2967_wdt_notify_sys(struct notifier_block *this,
+			     unsigned long code, void *unused)
+{
+	struct zx2967_wdt *wdt = container_of(this, struct zx2967_wdt,
+					      reboot_handler);
+
+	wdt->flags |= ZX2967_WDT_FLAG_REBOOT_MON;
+	switch (code) {
+	case SYS_HALT:
+	case SYS_POWER_OFF:
+	case SYS_RESTART:
+		zx2967_wdt_fix_sysdown(wdt);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int zx2967_wdt_restart(struct notifier_block *this,
+			      unsigned long mode, void *cmd)
+{
+	struct zx2967_wdt *wdt;
+
+	wdt = container_of(this, struct zx2967_wdt, restart_handler);
+
+	zx2967_wdt_stop(&wdt->wdt_device);
+
+	zx2967_wdt_write_reg(0x80, wdt->reg_base + ZX2967_WDT_LOAD_REG);
+	zx2967_wdt_refresh(wdt);
+	zx2967_wdt_write_reg(ZX2967_WDT_START_EN,
+			     wdt->reg_base + ZX2967_WDT_START_REG);
+
+	zx2967_wdt_start(&wdt->wdt_device);
+	/* wait for reset*/
+	mdelay(500);
+
+	return NOTIFY_DONE;
+}
+
+static void zx2967_reset_mask_config(struct device *dev)
+{
+	struct device_node *np = NULL;
+	void __iomem *reg;
+	unsigned int  val, mask, config, size;
+	const unsigned int *prop;
+
+	prop = of_get_property(dev->of_node, "reset-mask-config", &size);
+	if (size < (sizeof(*prop) * 2)) {
+		dev_err(dev, "bad data for reset-mask-config");
+		return;
+	}
+	config = be32_to_cpup(prop++);
+	mask = be32_to_cpup(prop);
+	np = of_find_compatible_node(NULL, NULL, "zte,aon-sysctrl");
+	if (!np) {
+		dev_err(dev, "Cannot found pcu device node\n");
+		return;
+	}
+	reg = of_iomap(np, 0) + ZX2967_RESET_MASK_REG;
+	of_node_put(np);
+
+	val = readl(reg);
+	val &= ~mask;
+	val |= config;
+	writel(val, reg);
+}
+
+static int zx2967_wdt_probe(struct platform_device *pdev)
+{
+	struct device *dev;
+	struct zx2967_wdt *wdt;
+	struct resource *base;
+	int err, ret = 0;
+	unsigned int rate, val;
+
+	struct reset_control *rstc;
+
+	dev = &pdev->dev;
+
+	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	platform_set_drvdata(pdev, wdt);
+
+	wdt->dev = dev;
+	spin_lock_init(&wdt->lock);
+
+	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 (of_find_property(dev->of_node, "reset-mask-config", NULL))
+		zx2967_reset_mask_config(dev);
+
+	wdt->reboot_handler.notifier_call = zx2967_wdt_notify_sys;
+	ret = register_reboot_notifier(&wdt->reboot_handler);
+	wdt->clock = devm_clk_get(dev, "wdtclk");
+	if (IS_ERR(wdt->clock)) {
+		dev_err(dev, "failed to find watchdog clock source\n");
+		ret = PTR_ERR(wdt->clock);
+		goto out;
+	}
+	ret = clk_prepare_enable(wdt->clock);
+	if (ret < 0) {
+		dev_err(dev, "failed to enable clock\n");
+		goto out;
+	}
+
+	rate = clk_get_rate(wdt->clock);
+	if (rate == 24000000)
+		ret = clk_set_rate(wdt->clock, 32768);
+	rate = clk_get_rate(wdt->clock);
+
+	rstc = devm_reset_control_get(dev, "wdtrst");
+	if (!rstc) {
+		dev_info(dev, "rstc get failed");
+	} else {
+		reset_control_assert(rstc);
+		mdelay(10);
+		reset_control_deassert(rstc);
+	}
+
+	watchdog_set_drvdata(&wdt->wdt_device, wdt);
+
+	watchdog_init_timeout(&wdt->wdt_device, timeout, &pdev->dev);
+	watchdog_set_nowayout(&wdt->wdt_device, nowayout);
+
+	zx2967_wdt_stop(&wdt->wdt_device);
+
+	err = watchdog_register_device(&wdt->wdt_device);
+	if (unlikely(err)) {
+		ret = err;
+		goto fail_register;
+	}
+
+	wdt->restart_handler.notifier_call = zx2967_wdt_restart;
+	wdt->restart_handler.priority = 128;
+	ret = register_restart_handler(&wdt->restart_handler);
+	if (ret) {
+		pr_err("cannot register restart handler, %d\n", ret);
+		goto fail_restart;
+	}
+
+	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
+	dev_info(&pdev->dev, "watchdog enabled (timeout=%d sec, nowayout=%d)",
+		 wdt->wdt_device.timeout, nowayout);
+
+	return 0;
+
+fail_restart:
+	watchdog_unregister_device(&wdt->wdt_device);
+fail_register:
+	clk_disable_unprepare(wdt->clock);
+out:
+	return ret;
+}
+
+static int zx2967_wdt_remove(struct platform_device *pdev)
+{
+	struct zx2967_wdt *wdt = platform_get_drvdata(pdev);
+
+	unregister_restart_handler(&wdt->restart_handler);
+	watchdog_unregister_device(&wdt->wdt_device);
+	clk_disable_unprepare(wdt->clock);
+
+	return 0;
+}
+
+static void zx2967_wdt_shutdown(struct platform_device *pdev)
+{
+	struct zx2967_wdt *wdt = platform_get_drvdata(pdev);
+
+	if (!(wdt->flags & ZX2967_WDT_FLAG_REBOOT_MON))
+		zx2967_wdt_stop(&wdt->wdt_device);
+}
+
+static const struct of_device_id zx2967_wdt_match[] = {
+	{ .compatible = "zte,zx296718-wdt", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, zx2967_wdt_match);
+
+static const struct platform_device_id zx2967_wdt_ids[] = {
+	{ .name = "zx2967-wdt", },
+	{}
+};
+MODULE_DEVICE_TABLE(platform, zx2967_wdt_ids);
+
+static struct platform_driver zx2967_wdt_driver = {
+	.probe		= zx2967_wdt_probe,
+	.remove		= zx2967_wdt_remove,
+	.shutdown	= zx2967_wdt_shutdown,
+	.id_table	= zx2967_wdt_ids,
+	.driver		= {
+		.name	= "zx2967-wdt",
+		.of_match_table	= of_match_ptr(zx2967_wdt_match),
+	},
+};
+module_platform_driver(zx2967_wdt_driver);
+
+MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
+MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
+MODULE_LICENSE("GPL");
-- 
2.7.4

Re: [PATCH v1 1/3] dt: bindings: add documentation for zx2967 family watchdog controller

[Shawn Guo]

On Mon, Jan 16, 2017 at 12:19:53PM +0800, Baoyou Xie wrote:
> This patch adds dt-binding documentation for zx2967 family
> watchdog controller.
> 
> Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
> ---
>  .../bindings/watchdog/zte,zx2967-wdt.txt           | 29 ++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt b/Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt
> new file mode 100644
> index 0000000..0fe0d40
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt
> @@ -0,0 +1,29 @@
> +ZTE zx2967 Watchdog timer
> +
> +Required properties:
> +
> +- compatible : should be one of the following.
> +       * zte,zx296718-wdt
> +- reg : Specifies base physical address and size of the registers.
> +- clocks : Pairs of phandle and specifier referencing the controller's clocks.
> +- clock-names: "wdtclk" for the watchdog clock.

clock-names only makes sense when there are multiple clock phandles in
'clocks' property.  When clock-names is not present, the driver code
calls devm_clk_get() with the second parameter being NULL.

> +- resets : Reference to the reset controller controlling the watchdog
> +           controller.
> +- reset-names : Must include the following entries:
> +       * wdtrst

Same as clock-names.

> +
> +Optional properties:
> +
> +- reset-mask-config : Mask and configuare value that be wrote to aon-sysctrl.

First of all, for vendor specific properties, we should have a vendor
prefix, something like "zte,reset-mask-config".

Secondly, we should really have more comments to explain why this
property is optional, i.e. in which cases it should be present, and in
which cases it can be missing.  Also, the relationship between this
reset and 'resets = <&toprst 35>' should be explained a bit as well.

Shawn

> +
> +Example:
> +
> +wdt_ares: watchdog@1465000 {
> +	compatible = "zte,zx296718-wdt";
> +	reg = <0x1465000 0x1000>;
> +	clocks = <&topcrm WDT_WCLK>;
> +	clock-names = "wdtclk";
> +	resets = <&toprst 35>;
> +	reset-names = "wdtrst";
> +	reset-mask-config = <1 0x115>;
> +};
> -- 
> 2.7.4
> 

Re: [PATCH v1 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Jun Nie]

On 2017年01月16日 12:19, Baoyou Xie wrote:
> This patch adds watchdog controller driver for ZTE's zx2967 family.
>
> Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
> ---
>  drivers/watchdog/Kconfig      |  10 ++
>  drivers/watchdog/Makefile     |   1 +
>  drivers/watchdog/zx2967_wdt.c | 405 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 416 insertions(+)
>  create mode 100644 drivers/watchdog/zx2967_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 3eb58cb..79027da 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 caa9f4a..ea08925 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..8791dd2
> --- /dev/null
> +++ b/drivers/watchdog/zx2967_wdt.c
> @@ -0,0 +1,405 @@
> +/*
> + * watchdog driver for ZTE's zx2967 family
> + *
> + * Copyright (C) 2017 ZTE Ltd.
> + *
> + * Author: Baoyou Xie <baoyou.xie@linaro.org>
> + *
> + * License terms: GNU General Public License (GPL) version 2
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/reboot.h>
> +#include <linux/reset.h>
> +#include <linux/watchdog.h>
> +
> +#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_FLAG_REBOOT_MON		(1 << 0)
> +
> +#define ZX2967_RESET_MASK_REG			0xb0
> +
> +#define zx2967_wdt_write_reg(v, r) \
> +			writel((v) | ZX2967_WDT_WRITEKEY, r)
> +#define zx2967_wdt_read_reg(r)			readl(r)

For writel and readl, *_relaxed is recommended.

> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +static unsigned int timeout = ZX2967_WDT_DEFAULT_TIMEOUT;
> +
> +struct zx2967_wdt {
> +	struct device		*dev;
> +	struct clk		*clock;
> +	void __iomem		*reg_base;
> +	unsigned int		conf;
> +	unsigned int		load;
> +	unsigned int		flags;
> +	spinlock_t		lock;
> +	struct watchdog_device	wdt_device;
> +	struct notifier_block	restart_handler;
> +	struct notifier_block	reboot_handler;
> +};
> +
> +static void zx2967_wdt_refresh(struct zx2967_wdt *wdt)
> +{
> +	unsigned int val;
> +
> +	spin_lock(&wdt->lock);
> +
> +	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_REFRESH_REG);
> +	val ^= ZX2967_WDT_REFRESH_MASK;
> +	zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_REFRESH_REG);
> +
> +	spin_unlock(&wdt->lock);
> +}
> +
> +static void __zx2967_wdt_stop(struct zx2967_wdt *wdt)
> +{
> +	unsigned int val;
> +
> +	spin_lock(&wdt->lock);
> +
> +	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
> +	val &= ~(ZX2967_WDT_START_EN);
> +	zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_START_REG);
> +
> +	spin_unlock(&wdt->lock);
> +}
> +
> +static void __zx2967_wdt_start(struct zx2967_wdt *wdt)
> +{
> +	unsigned int val;
> +
> +	spin_lock(&wdt->lock);
> +
> +	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
> +	val |= ZX2967_WDT_START_EN;
> +	zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_START_REG);
> +
> +	spin_unlock(&wdt->lock);
> +}
> +
> +static unsigned int
> +__zx2967_wdt_set_timeout(struct zx2967_wdt *wdt, unsigned int timeout)
> +{
> +	unsigned int freq = clk_get_rate(wdt->clock);
> +	unsigned int divisor = ZX2967_WDT_DIV_DEFAULT, count;
> +
> +	count = timeout * 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_write_reg(ZX2967_WDT_CFG_DIV(divisor),
> +			     wdt->reg_base + ZX2967_WDT_CFG_REG);
> +	zx2967_wdt_write_reg(count, wdt->reg_base + ZX2967_WDT_LOAD_REG);

No spin lock here. Do we really need the spin lock?

> +	zx2967_wdt_refresh(wdt);
> +
> +	wdt->load = count;
> +	dev_info(wdt->dev, "count=%d, timeout=%d, divisor=%d\n",
> +		 count, timeout, divisor);
> +
> +	return (count * divisor) / freq;
> +}
> +
> +static int zx2967_wdt_set_timeout(struct watchdog_device *wdd,
> +				  unsigned int timeout)
> +{
> +	struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> +	if (watchdog_timeout_invalid(&wdt->wdt_device, timeout)) {
> +		dev_err(wdt->dev, "timeout %d is invalid\n", timeout);
> +
> +		return -EINVAL;
> +	}
> +
> +	wdd->timeout = __zx2967_wdt_set_timeout(wdt, timeout);
> +
> +	return 0;
> +}
> +
> +static int zx2967_wdt_start(struct watchdog_device *wdd)
> +{
> +	struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> +	__zx2967_wdt_stop(wdt);
> +	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_fix_sysdown(struct zx2967_wdt *wdt)
> +{
> +	__zx2967_wdt_stop(wdt);
> +	__zx2967_wdt_set_timeout(wdt, 15);
> +	__zx2967_wdt_start(wdt);
> +}
> +
> +static int zx2967_wdt_notify_sys(struct notifier_block *this,
> +			     unsigned long code, void *unused)
> +{
> +	struct zx2967_wdt *wdt = container_of(this, struct zx2967_wdt,
> +					      reboot_handler);
> +
> +	wdt->flags |= ZX2967_WDT_FLAG_REBOOT_MON;
> +	switch (code) {
> +	case SYS_HALT:
> +	case SYS_POWER_OFF:
> +	case SYS_RESTART:
> +		zx2967_wdt_fix_sysdown(wdt);
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
> +static int zx2967_wdt_restart(struct notifier_block *this,
> +			      unsigned long mode, void *cmd)
> +{
> +	struct zx2967_wdt *wdt;
> +
> +	wdt = container_of(this, struct zx2967_wdt, restart_handler);
> +
> +	zx2967_wdt_stop(&wdt->wdt_device);
> +
> +	zx2967_wdt_write_reg(0x80, wdt->reg_base + ZX2967_WDT_LOAD_REG);
> +	zx2967_wdt_refresh(wdt);
> +	zx2967_wdt_write_reg(ZX2967_WDT_START_EN,
> +			     wdt->reg_base + ZX2967_WDT_START_REG);
> +
> +	zx2967_wdt_start(&wdt->wdt_device);
> +	/* wait for reset*/
> +	mdelay(500);
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static void zx2967_reset_mask_config(struct device *dev)
> +{
> +	struct device_node *np = NULL;
> +	void __iomem *reg;
> +	unsigned int  val, mask, config, size;
> +	const unsigned int *prop;
> +
> +	prop = of_get_property(dev->of_node, "reset-mask-config", &size);
> +	if (size < (sizeof(*prop) * 2)) {
> +		dev_err(dev, "bad data for reset-mask-config");
> +		return;
> +	}
> +	config = be32_to_cpup(prop++);
> +	mask = be32_to_cpup(prop);
> +	np = of_find_compatible_node(NULL, NULL, "zte,aon-sysctrl");
> +	if (!np) {
> +		dev_err(dev, "Cannot found pcu device node\n");
> +		return;
> +	}
> +	reg = of_iomap(np, 0) + ZX2967_RESET_MASK_REG;
> +	of_node_put(np);
> +
> +	val = readl(reg);
> +	val &= ~mask;
> +	val |= config;
> +	writel(val, reg);
> +}
> +
> +static int zx2967_wdt_probe(struct platform_device *pdev)
> +{
> +	struct device *dev;
> +	struct zx2967_wdt *wdt;
> +	struct resource *base;
> +	int err, ret = 0;
> +	unsigned int rate, val;
> +
> +	struct reset_control *rstc;
> +
> +	dev = &pdev->dev;
> +
> +	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> +	if (!wdt) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +
> +	platform_set_drvdata(pdev, wdt);
> +
> +	wdt->dev = dev;
> +	spin_lock_init(&wdt->lock);
> +
> +	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 (of_find_property(dev->of_node, "reset-mask-config", NULL))
> +		zx2967_reset_mask_config(dev);
> +
> +	wdt->reboot_handler.notifier_call = zx2967_wdt_notify_sys;
> +	ret = register_reboot_notifier(&wdt->reboot_handler);
> +	wdt->clock = devm_clk_get(dev, "wdtclk");
> +	if (IS_ERR(wdt->clock)) {
> +		dev_err(dev, "failed to find watchdog clock source\n");
> +		ret = PTR_ERR(wdt->clock);
> +		goto out;
> +	}
> +	ret = clk_prepare_enable(wdt->clock);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to enable clock\n");
> +		goto out;
> +	}
> +
> +	rate = clk_get_rate(wdt->clock);
> +	if (rate == 24000000)
> +		ret = clk_set_rate(wdt->clock, 32768);
> +	rate = clk_get_rate(wdt->clock);

Do you want to check rate again? Or you want to just check set_rate 
return value?

> +
> +	rstc = devm_reset_control_get(dev, "wdtrst");
> +	if (!rstc) {
> +		dev_info(dev, "rstc get failed");

dev_err() may be more feasible.

> +	} else {
> +		reset_control_assert(rstc);
> +		mdelay(10);
> +		reset_control_deassert(rstc);
> +	}
> +
> +	watchdog_set_drvdata(&wdt->wdt_device, wdt);
> +
> +	watchdog_init_timeout(&wdt->wdt_device, timeout, &pdev->dev);
> +	watchdog_set_nowayout(&wdt->wdt_device, nowayout);
> +
> +	zx2967_wdt_stop(&wdt->wdt_device);
> +
> +	err = watchdog_register_device(&wdt->wdt_device);
> +	if (unlikely(err)) {
> +		ret = err;
> +		goto fail_register;
> +	}
> +
> +	wdt->restart_handler.notifier_call = zx2967_wdt_restart;
> +	wdt->restart_handler.priority = 128;
> +	ret = register_restart_handler(&wdt->restart_handler);
> +	if (ret) {
> +		pr_err("cannot register restart handler, %d\n", ret);
> +		goto fail_restart;
> +	}
> +
> +	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
> +	dev_info(&pdev->dev, "watchdog enabled (timeout=%d sec, nowayout=%d)",
> +		 wdt->wdt_device.timeout, nowayout);
> +
> +	return 0;
> +
> +fail_restart:
> +	watchdog_unregister_device(&wdt->wdt_device);
> +fail_register:
> +	clk_disable_unprepare(wdt->clock);
> +out:
> +	return ret;
> +}
> +
> +static int zx2967_wdt_remove(struct platform_device *pdev)
> +{
> +	struct zx2967_wdt *wdt = platform_get_drvdata(pdev);
> +
> +	unregister_restart_handler(&wdt->restart_handler);
> +	watchdog_unregister_device(&wdt->wdt_device);
> +	clk_disable_unprepare(wdt->clock);
> +
> +	return 0;
> +}
> +
> +static void zx2967_wdt_shutdown(struct platform_device *pdev)
> +{
> +	struct zx2967_wdt *wdt = platform_get_drvdata(pdev);
> +
> +	if (!(wdt->flags & ZX2967_WDT_FLAG_REBOOT_MON))
> +		zx2967_wdt_stop(&wdt->wdt_device);
> +}
> +
> +static const struct of_device_id zx2967_wdt_match[] = {
> +	{ .compatible = "zte,zx296718-wdt", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, zx2967_wdt_match);
> +
> +static const struct platform_device_id zx2967_wdt_ids[] = {
> +	{ .name = "zx2967-wdt", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(platform, zx2967_wdt_ids);
> +
> +static struct platform_driver zx2967_wdt_driver = {
> +	.probe		= zx2967_wdt_probe,
> +	.remove		= zx2967_wdt_remove,
> +	.shutdown	= zx2967_wdt_shutdown,
> +	.id_table	= zx2967_wdt_ids,
> +	.driver		= {
> +		.name	= "zx2967-wdt",
> +		.of_match_table	= of_match_ptr(zx2967_wdt_match),
> +	},
> +};
> +module_platform_driver(zx2967_wdt_driver);
> +
> +MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
> +MODULE_LICENSE("GPL");
>

Re: [PATCH v1 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Shawn Guo]

On Mon, Jan 16, 2017 at 12:19:55PM +0800, Baoyou Xie wrote:
> This patch adds watchdog controller driver for ZTE's zx2967 family.
> 
> Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
> ---
>  drivers/watchdog/Kconfig      |  10 ++
>  drivers/watchdog/Makefile     |   1 +
>  drivers/watchdog/zx2967_wdt.c | 405 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 416 insertions(+)
>  create mode 100644 drivers/watchdog/zx2967_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 3eb58cb..79027da 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 caa9f4a..ea08925 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..8791dd2
> --- /dev/null
> +++ b/drivers/watchdog/zx2967_wdt.c
> @@ -0,0 +1,405 @@
> +/*
> + * watchdog driver for ZTE's zx2967 family
> + *
> + * Copyright (C) 2017 ZTE Ltd.
> + *
> + * Author: Baoyou Xie <baoyou.xie@linaro.org>
> + *
> + * License terms: GNU General Public License (GPL) version 2
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/reboot.h>
> +#include <linux/reset.h>
> +#include <linux/watchdog.h>
> +
> +#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)

Please have a space before and after '&' operator.

> +#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_FLAG_REBOOT_MON		(1 << 0)
> +
> +#define ZX2967_RESET_MASK_REG			0xb0
> +
> +#define zx2967_wdt_write_reg(v, r) \
> +			writel((v) | ZX2967_WDT_WRITEKEY, r)
> +#define zx2967_wdt_read_reg(r)			readl(r)

I think inline functions are better than macros in this case.

> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +static unsigned int timeout = ZX2967_WDT_DEFAULT_TIMEOUT;

The variable name is too generic.  For example, the same name is used in
functions like __zx2967_wdt_set_timeout().

> +
> +struct zx2967_wdt {
> +	struct device		*dev;
> +	struct clk		*clock;
> +	void __iomem		*reg_base;
> +	unsigned int		conf;
> +	unsigned int		load;
> +	unsigned int		flags;
> +	spinlock_t		lock;
> +	struct watchdog_device	wdt_device;
> +	struct notifier_block	restart_handler;
> +	struct notifier_block	reboot_handler;
> +};
> +
> +static void zx2967_wdt_refresh(struct zx2967_wdt *wdt)
> +{
> +	unsigned int val;

u32 for 32-bit register access is more readable.

> +
> +	spin_lock(&wdt->lock);
> +
> +	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_REFRESH_REG);
> +	val ^= ZX2967_WDT_REFRESH_MASK;
> +	zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_REFRESH_REG);
> +
> +	spin_unlock(&wdt->lock);
> +}
> +
> +static void __zx2967_wdt_stop(struct zx2967_wdt *wdt)
> +{
> +	unsigned int val;
> +
> +	spin_lock(&wdt->lock);
> +
> +	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
> +	val &= ~(ZX2967_WDT_START_EN);

The parentheses is not needed.

> +	zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_START_REG);
> +
> +	spin_unlock(&wdt->lock);
> +}
> +
> +static void __zx2967_wdt_start(struct zx2967_wdt *wdt)
> +{
> +	unsigned int val;
> +
> +	spin_lock(&wdt->lock);
> +
> +	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
> +	val |= ZX2967_WDT_START_EN;
> +	zx2967_wdt_write_reg(val, wdt->reg_base + ZX2967_WDT_START_REG);
> +
> +	spin_unlock(&wdt->lock);
> +}
> +
> +static unsigned int
> +__zx2967_wdt_set_timeout(struct zx2967_wdt *wdt, unsigned int timeout)
> +{
> +	unsigned int freq = clk_get_rate(wdt->clock);
> +	unsigned int divisor = ZX2967_WDT_DIV_DEFAULT, count;

Unless the variables are closely related, it's more conventional to have
each variable on a new line.

> +
> +	count = timeout * 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_write_reg(ZX2967_WDT_CFG_DIV(divisor),
> +			     wdt->reg_base + ZX2967_WDT_CFG_REG);
> +	zx2967_wdt_write_reg(count, wdt->reg_base + ZX2967_WDT_LOAD_REG);
> +	zx2967_wdt_refresh(wdt);
> +
> +	wdt->load = count;
> +	dev_info(wdt->dev, "count=%d, timeout=%d, divisor=%d\n",
> +		 count, timeout, divisor);

Noisy.  Maybe dev_dbg().

> +
> +	return (count * divisor) / freq;
> +}
> +
> +static int zx2967_wdt_set_timeout(struct watchdog_device *wdd,
> +				  unsigned int timeout)
> +{
> +	struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> +	if (watchdog_timeout_invalid(&wdt->wdt_device, timeout)) {
> +		dev_err(wdt->dev, "timeout %d is invalid\n", timeout);
> +

Drop the newline.

> +		return -EINVAL;
> +	}
> +
> +	wdd->timeout = __zx2967_wdt_set_timeout(wdt, timeout);
> +
> +	return 0;
> +}
> +
> +static int zx2967_wdt_start(struct watchdog_device *wdd)
> +{
> +	struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> +	__zx2967_wdt_stop(wdt);
> +	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_fix_sysdown(struct zx2967_wdt *wdt)
> +{
> +	__zx2967_wdt_stop(wdt);
> +	__zx2967_wdt_set_timeout(wdt, 15);
> +	__zx2967_wdt_start(wdt);
> +}
> +
> +static int zx2967_wdt_notify_sys(struct notifier_block *this,
> +			     unsigned long code, void *unused)
> +{
> +	struct zx2967_wdt *wdt = container_of(this, struct zx2967_wdt,
> +					      reboot_handler);
> +
> +	wdt->flags |= ZX2967_WDT_FLAG_REBOOT_MON;
> +	switch (code) {
> +	case SYS_HALT:
> +	case SYS_POWER_OFF:
> +	case SYS_RESTART:
> +		zx2967_wdt_fix_sysdown(wdt);
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
> +static int zx2967_wdt_restart(struct notifier_block *this,
> +			      unsigned long mode, void *cmd)
> +{
> +	struct zx2967_wdt *wdt;
> +
> +	wdt = container_of(this, struct zx2967_wdt, restart_handler);
> +
> +	zx2967_wdt_stop(&wdt->wdt_device);
> +
> +	zx2967_wdt_write_reg(0x80, wdt->reg_base + ZX2967_WDT_LOAD_REG);
> +	zx2967_wdt_refresh(wdt);
> +	zx2967_wdt_write_reg(ZX2967_WDT_START_EN,
> +			     wdt->reg_base + ZX2967_WDT_START_REG);
> +
> +	zx2967_wdt_start(&wdt->wdt_device);
> +	/* wait for reset*/
> +	mdelay(500);
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static void zx2967_reset_mask_config(struct device *dev)
> +{
> +	struct device_node *np = NULL;
> +	void __iomem *reg;
> +	unsigned int  val, mask, config, size;
> +	const unsigned int *prop;
> +
> +	prop = of_get_property(dev->of_node, "reset-mask-config", &size);
> +	if (size < (sizeof(*prop) * 2)) {
> +		dev_err(dev, "bad data for reset-mask-config");
> +		return;
> +	}
> +	config = be32_to_cpup(prop++);
> +	mask = be32_to_cpup(prop);
> +	np = of_find_compatible_node(NULL, NULL, "zte,aon-sysctrl");
> +	if (!np) {
> +		dev_err(dev, "Cannot found pcu device node\n");
> +		return;
> +	}
> +	reg = of_iomap(np, 0) + ZX2967_RESET_MASK_REG;
> +	of_node_put(np);

We should use syscon interface to access sysctrl block.

> +
> +	val = readl(reg);
> +	val &= ~mask;
> +	val |= config;
> +	writel(val, reg);
> +}
> +
> +static int zx2967_wdt_probe(struct platform_device *pdev)
> +{
> +	struct device *dev;
> +	struct zx2967_wdt *wdt;
> +	struct resource *base;
> +	int err, ret = 0;
> +	unsigned int rate, val;
> +
> +	struct reset_control *rstc;
> +
> +	dev = &pdev->dev;
> +
> +	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
> +	if (!wdt) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}

return -ENOMEM;

> +
> +	platform_set_drvdata(pdev, wdt);
> +
> +	wdt->dev = dev;
> +	spin_lock_init(&wdt->lock);
> +
> +	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);

It should be error checked.

> +
> +	if (of_find_property(dev->of_node, "reset-mask-config", NULL))
> +		zx2967_reset_mask_config(dev);
> +
> +	wdt->reboot_handler.notifier_call = zx2967_wdt_notify_sys;
> +	ret = register_reboot_notifier(&wdt->reboot_handler);
> +	wdt->clock = devm_clk_get(dev, "wdtclk");
> +	if (IS_ERR(wdt->clock)) {
> +		dev_err(dev, "failed to find watchdog clock source\n");
> +		ret = PTR_ERR(wdt->clock);
> +		goto out;
> +	}
> +	ret = clk_prepare_enable(wdt->clock);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to enable clock\n");
> +		goto out;
> +	}
> +
> +	rate = clk_get_rate(wdt->clock);
> +	if (rate == 24000000)
> +		ret = clk_set_rate(wdt->clock, 32768);
> +	rate = clk_get_rate(wdt->clock);
> +
> +	rstc = devm_reset_control_get(dev, "wdtrst");
> +	if (!rstc) {
> +		dev_info(dev, "rstc get failed");
> +	} else {
> +		reset_control_assert(rstc);
> +		mdelay(10);
> +		reset_control_deassert(rstc);
> +	}
> +
> +	watchdog_set_drvdata(&wdt->wdt_device, wdt);
> +
> +	watchdog_init_timeout(&wdt->wdt_device, timeout, &pdev->dev);
> +	watchdog_set_nowayout(&wdt->wdt_device, nowayout);
> +
> +	zx2967_wdt_stop(&wdt->wdt_device);
> +
> +	err = watchdog_register_device(&wdt->wdt_device);
> +	if (unlikely(err)) {
> +		ret = err;
> +		goto fail_register;
> +	}
> +
> +	wdt->restart_handler.notifier_call = zx2967_wdt_restart;
> +	wdt->restart_handler.priority = 128;
> +	ret = register_restart_handler(&wdt->restart_handler);
> +	if (ret) {
> +		pr_err("cannot register restart handler, %d\n", ret);

dev_err()

> +		goto fail_restart;
> +	}
> +
> +	val = zx2967_wdt_read_reg(wdt->reg_base + ZX2967_WDT_START_REG);
> +	dev_info(&pdev->dev, "watchdog enabled (timeout=%d sec, nowayout=%d)",
> +		 wdt->wdt_device.timeout, nowayout);
> +
> +	return 0;
> +
> +fail_restart:
> +	watchdog_unregister_device(&wdt->wdt_device);
> +fail_register:
> +	clk_disable_unprepare(wdt->clock);
> +out:
> +	return ret;
> +}
> +
> +static int zx2967_wdt_remove(struct platform_device *pdev)
> +{
> +	struct zx2967_wdt *wdt = platform_get_drvdata(pdev);
> +
> +	unregister_restart_handler(&wdt->restart_handler);
> +	watchdog_unregister_device(&wdt->wdt_device);
> +	clk_disable_unprepare(wdt->clock);
> +
> +	return 0;
> +}
> +
> +static void zx2967_wdt_shutdown(struct platform_device *pdev)
> +{
> +	struct zx2967_wdt *wdt = platform_get_drvdata(pdev);
> +
> +	if (!(wdt->flags & ZX2967_WDT_FLAG_REBOOT_MON))
> +		zx2967_wdt_stop(&wdt->wdt_device);
> +}
> +
> +static const struct of_device_id zx2967_wdt_match[] = {
> +	{ .compatible = "zte,zx296718-wdt", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, zx2967_wdt_match);
> +
> +static const struct platform_device_id zx2967_wdt_ids[] = {
> +	{ .name = "zx2967-wdt", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(platform, zx2967_wdt_ids);

This is not needed, as we do not support platform probe but only DT on
ZTE platforms.

Shawn

> +
> +static struct platform_driver zx2967_wdt_driver = {
> +	.probe		= zx2967_wdt_probe,
> +	.remove		= zx2967_wdt_remove,
> +	.shutdown	= zx2967_wdt_shutdown,
> +	.id_table	= zx2967_wdt_ids,
> +	.driver		= {
> +		.name	= "zx2967-wdt",
> +		.of_match_table	= of_match_ptr(zx2967_wdt_match),
> +	},
> +};
> +module_platform_driver(zx2967_wdt_driver);
> +
> +MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
> +MODULE_LICENSE("GPL");
> -- 
> 2.7.4
>