[PATCH v5 1/3] dt: bindings: add documentation for zx2967 family watchdog controller

[PATCH v5 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>
Acked-by: Rob Herring <robh@kernel.org>
---
 .../bindings/watchdog/zte,zx2967-wdt.txt           | 31 ++++++++++++++++++++++
 1 file changed, 31 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..772403a
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt
@@ -0,0 +1,31 @@
+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.
+- resets : Reference to the reset controller controlling the watchdog
+           controller.
+
+Optional properties:
+
+- zte,wdt-reset-sysctrl : Directs how to reset system by the watchdog.
+	if we don't want to restart system when watchdog been triggered,
+	it's not required, vice versa.
+	It should include following fields.
+	  * phandle of aon-sysctrl.
+	  * offset of register that be written, should be 0xb0.
+	  * configure value that be written to aon-sysctrl.
+	  * bit mask, corresponding bits will be affected.
+
+Example:
+
+wdt: watchdog@1465000 {
+	compatible = "zte,zx296718-wdt";
+	reg = <0x1465000 0x1000>;
+	clocks = <&topcrm WDT_WCLK>;
+	resets = <&toprst 35>;
+	zte,wdt-reset-sysctrl = <&aon_sysctrl 0xb0 1 0x115>;
+};
-- 
2.7.4

[PATCH v5 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-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
---
 .../bindings/watchdog/zte,zx2967-wdt.txt           | 31 ++++++++++++++++++++++
 1 file changed, 31 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..772403a
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt
@@ -0,0 +1,31 @@
+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.
+- resets : Reference to the reset controller controlling the watchdog
+           controller.
+
+Optional properties:
+
+- zte,wdt-reset-sysctrl : Directs how to reset system by the watchdog.
+	if we don't want to restart system when watchdog been triggered,
+	it's not required, vice versa.
+	It should include following fields.
+	  * phandle of aon-sysctrl.
+	  * offset of register that be written, should be 0xb0.
+	  * configure value that be written to aon-sysctrl.
+	  * bit mask, corresponding bits will be affected.
+
+Example:
+
+wdt: watchdog@1465000 {
+	compatible = "zte,zx296718-wdt";
+	reg = <0x1465000 0x1000>;
+	clocks = <&topcrm WDT_WCLK>;
+	resets = <&toprst 35>;
+	zte,wdt-reset-sysctrl = <&aon_sysctrl 0xb0 1 0x115>;
+};
-- 
2.7.4

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[PATCH v5 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>
Acked-by: Rob Herring <robh@kernel.org>
---
 .../bindings/watchdog/zte,zx2967-wdt.txt           | 31 ++++++++++++++++++++++
 1 file changed, 31 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..772403a
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/zte,zx2967-wdt.txt
@@ -0,0 +1,31 @@
+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.
+- resets : Reference to the reset controller controlling the watchdog
+           controller.
+
+Optional properties:
+
+- zte,wdt-reset-sysctrl : Directs how to reset system by the watchdog.
+	if we don't want to restart system when watchdog been triggered,
+	it's not required, vice versa.
+	It should include following fields.
+	  * phandle of aon-sysctrl.
+	  * offset of register that be written, should be 0xb0.
+	  * configure value that be written to aon-sysctrl.
+	  * bit mask, corresponding bits will be affected.
+
+Example:
+
+wdt: watchdog at 1465000 {
+	compatible = "zte,zx296718-wdt";
+	reg = <0x1465000 0x1000>;
+	clocks = <&topcrm WDT_WCLK>;
+	resets = <&toprst 35>;
+	zte,wdt-reset-sysctrl = <&aon_sysctrl 0xb0 1 0x115>;
+};
-- 
2.7.4

[PATCH v5 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 edfdea3..275c434 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1990,11 +1990,13 @@ 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 v5 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 edfdea3..275c434 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1990,11 +1990,13 @@ 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 v5 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 | 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 <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/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.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_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);
+	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);
+
+	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 <baoyou.xie@linaro.org>");
+MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

[PATCH v5 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 | 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 <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/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.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_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);
+	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);
+
+	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 <baoyou.xie@linaro.org>");
+MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

Re: [PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Guenter Roeck]

On 01/24/2017 12:58 AM, 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 | 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 <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/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.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

Why not use the real maximum ? Just wondering.

> +#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,

Does that make the code easier to read ? I presonally like being able to grep for
"options" in the driver to get a glimpse.

> +	.firmware_version =	0,

Initializing a static field to 0 is unnecessary.

> +	.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);
> +	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);

Another comment suggested adding
	of_node_put(out_args.np);
here.

> +}
> +
> +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);
> +
> +	watchdog_set_drvdata(&wdt->wdt_device, wdt);
> +	watchdog_set_nowayout(&wdt->wdt_device, WATCHDOG_NOWAYOUT);

A call to watchdog_init_timeout() may be valuable here to catch
timeout values from devicetree. Otherwise, displaying the selected timeout
below (which is a constant) doesn't really add much value.

> +
> +	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);

As asked before - why try to unregister if the registration failed ?

> +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 <baoyou.xie@linaro.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
> +MODULE_LICENSE("GPL v2");
>

Re: [PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Guenter Roeck]

On 01/24/2017 12:58 AM, Baoyou Xie wrote:
> This patch adds watchdog controller driver for ZTE's zx2967 family.
>
> Signed-off-by: Baoyou Xie <baoyou.xie-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> ---
>  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 <baoyou.xie-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
> + *
> + * License terms: GNU General Public License (GPL) version 2
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.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

Why not use the real maximum ? Just wondering.

> +#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,

Does that make the code easier to read ? I presonally like being able to grep for
"options" in the driver to get a glimpse.

> +	.firmware_version =	0,

Initializing a static field to 0 is unnecessary.

> +	.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);
> +	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);

Another comment suggested adding
	of_node_put(out_args.np);
here.

> +}
> +
> +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);
> +
> +	watchdog_set_drvdata(&wdt->wdt_device, wdt);
> +	watchdog_set_nowayout(&wdt->wdt_device, WATCHDOG_NOWAYOUT);

A call to watchdog_init_timeout() may be valuable here to catch
timeout values from devicetree. Otherwise, displaying the selected timeout
below (which is a constant) doesn't really add much value.

> +
> +	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);

As asked before - why try to unregister if the registration failed ?

> +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 <baoyou.xie-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
> +MODULE_LICENSE("GPL v2");
>

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[PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Guenter Roeck]

On 01/24/2017 12:58 AM, 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 | 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 <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/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.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

Why not use the real maximum ? Just wondering.

> +#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,

Does that make the code easier to read ? I presonally like being able to grep for
"options" in the driver to get a glimpse.

> +	.firmware_version =	0,

Initializing a static field to 0 is unnecessary.

> +	.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);
> +	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);

Another comment suggested adding
	of_node_put(out_args.np);
here.

> +}
> +
> +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);
> +
> +	watchdog_set_drvdata(&wdt->wdt_device, wdt);
> +	watchdog_set_nowayout(&wdt->wdt_device, WATCHDOG_NOWAYOUT);

A call to watchdog_init_timeout() may be valuable here to catch
timeout values from devicetree. Otherwise, displaying the selected timeout
below (which is a constant) doesn't really add much value.

> +
> +	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);

As asked before - why try to unregister if the registration failed ?

> +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 <baoyou.xie@linaro.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
> +MODULE_LICENSE("GPL v2");
>

Re: [PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Mathieu Poirier]

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 <baoyou.xie@linaro.org>
> ---
>  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 <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/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.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_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 <baoyou.xie@linaro.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.7.4
> 

[PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Mathieu Poirier]

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 <baoyou.xie@linaro.org>
> ---
>  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 <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/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.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_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 <baoyou.xie@linaro.org>");
> +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.7.4
> 

Re: [PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Baoyou Xie]

[-- Attachment #1: Type: text/plain, Size: 11998 bytes --]

On 24 January 2017 at 22:50, Guenter Roeck <linux@roeck-us.net> wrote:

> On 01/24/2017 12:58 AM, 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 | 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 <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/mfd/syscon.h>
>> +#include <linux/module.h>
>> +#include <linux/of_address.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.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
>>
>
> Why not use the real maximum ? Just wondering.
>
> Obviously, 524 is the accruate value, but we believe 500 is long enough.
For accuracy, I will modify this value to 524 in next version.

>
> +#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,
>>
>
> Does that make the code easier to read ? I presonally like being able to
> grep for
> "options" in the driver to get a glimpse.
>
> +       .firmware_version =     0,
>>
>
> Initializing a static field to 0 is unnecessary.
>
> ok.

>
> +       .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);
>> +       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);
>>
>
> Another comment suggested adding
>         of_node_put(out_args.np);
> here.
>
>
> is it really? most of the driver that call this function don't call
of_node_put. but it seems harmless to call of_node_put.


> +}
>> +
>> +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);
>> +
>> +       watchdog_set_drvdata(&wdt->wdt_device, wdt);
>> +       watchdog_set_nowayout(&wdt->wdt_device, WATCHDOG_NOWAYOUT);
>>
>
> A call to watchdog_init_timeout() may be valuable here to catch
> timeout values from devicetree. Otherwise, displaying the selected timeout
> below (which is a constant) doesn't really add much value.
>
> ok. I will modify the code and zte,zx2967-wdt.txt.


> +
>> +       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);
>>
>
> As asked before - why try to unregister if the registration failed ?
>
>
ok, fixed it.

> +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 <baoyou.xie@linaro.org>");
>> +MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
>> +MODULE_LICENSE("GPL v2");
>>
>>
>

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Re: [PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Guenter Roeck]

On 01/24/2017 06:16 PM, Baoyou Xie wrote:
>
[ ... ]
>         +
>         +       ret = of_parse_phandle_with_fixed_args(dev->of_node,
>         +                       "zte,wdt-reset-sysctrl", 3, 0, &out_args);
>         +       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 <http://out_args.np>);
>         +       if (IS_ERR(regmap))
>         +               return;
>         +
>         +       regmap_update_bits(regmap, offset, mask, config);
>
>
>     Another comment suggested adding
>             of_node_put(out_args.np <http://out_args.np>);
>     here.
>
>
> is it really? most of the driver that call this function don't call of_node_put. but it seems harmless to call of_node_put.
>
>
Even if everyone else is doing things wrong, that doesn't mean
that you should do the same, nor is it a good idea to use it
as argument.

Guenter

[PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Guenter Roeck]

On 01/24/2017 06:16 PM, Baoyou Xie wrote:
>
[ ... ]
>         +
>         +       ret = of_parse_phandle_with_fixed_args(dev->of_node,
>         +                       "zte,wdt-reset-sysctrl", 3, 0, &out_args);
>         +       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 <http://out_args.np>);
>         +       if (IS_ERR(regmap))
>         +               return;
>         +
>         +       regmap_update_bits(regmap, offset, mask, config);
>
>
>     Another comment suggested adding
>             of_node_put(out_args.np <http://out_args.np>);
>     here.
>
>
> is it really? most of the driver that call this function don't call of_node_put. but it seems harmless to call of_node_put.
>
>
Even if everyone else is doing things wrong, that doesn't mean
that you should do the same, nor is it a good idea to use it
as argument.

Guenter

Re: [PATCH v5 3/3] watchdog: zx2967: add watchdog controller driver for ZTE's zx2967 family

[Baoyou Xie]

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On 25 January 2017 at 10:43, Guenter Roeck <linux@roeck-us.net> wrote:

> On 01/24/2017 06:16 PM, Baoyou Xie wrote:
>
>>
>> [ ... ]
>
>>         +
>>         +       ret = of_parse_phandle_with_fixed_args(dev->of_node,
>>         +                       "zte,wdt-reset-sysctrl", 3, 0, &out_args);
>>         +       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 <
>> http://out_args.np>);
>>         +       if (IS_ERR(regmap))
>>         +               return;
>>         +
>>         +       regmap_update_bits(regmap, offset, mask, config);
>>
>>
>>     Another comment suggested adding
>>             of_node_put(out_args.np <http://out_args.np>);
>>     here.
>>
>>
>> is it really? most of the driver that call this function don't call
>> of_node_put. but it seems harmless to call of_node_put.
>>
>>
>> Even if everyone else is doing things wrong, that doesn't mean
> that you should do the same, nor is it a good idea to use it
> as argument.
>
> en, yes.
I have read the comment of of_parse_phandle_with_fixed_args. in v6 version,
I have fixed it.
thanks.


> Guenter
>
>

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