[PATCH v1 0/5] STM32 Independant watchdog

[PATCH v1 0/5] STM32 Independant watchdog

[Yannick Fertre]

Version 1:
- Initial commit

The purpose of this set of patches is to add a new watchdog driver for
stm32f429.
This driver was developed and tested on evaluation board stm32429i.

Yannick Fertre (5):
  dt-bindings: Document STM32 IWDG bindings
  drivers: watchdog: Add STM32 IWDG driver
  ARM: dts: stm32ap: Add watchdog support for STM32F429 SoC
  ARM: dts: stm32ap: Add watchdog support for STM32F429 eval board
  ARM: configs: Add watchdog support in STM32 defconfig

 .../devicetree/bindings/watchdog/st,stm32-iwdg.txt |  15 ++
 arch/arm/boot/dts/stm32429i-eval.dts               |   4 +
 arch/arm/boot/dts/stm32f429.dtsi                   |   9 +-
 arch/arm/configs/stm32_defconfig                   |   1 +
 drivers/watchdog/Kconfig                           |  11 +
 drivers/watchdog/Makefile                          |   1 +
 drivers/watchdog/stm32_iwdg.c                      | 289 +++++++++++++++++++++
 7 files changed, 329 insertions(+), 1 deletion(-)
 create mode 100644 Documentation/devicetree/bindings/watchdog/st,stm32-iwdg.txt
 create mode 100644 drivers/watchdog/stm32_iwdg.c

-- 
1.9.1

[PATCH v1 1/5] dt-bindings: Document STM32 IWDG bindings

[Yannick Fertre]

From: Yannick Fertre <yfertre.stm32@gmail.com>

This adds documentation of device tree bindings for the STM32 IWDG
(Independent WatchDoG).

Change-Id: Idadacc806d00205fe9af2e8606af229b4b760558
Signed-off-by: Yannick Fertre <yfertre.stm32@gmail.com>
Reviewed-on: https://gerrit.st.com/45217
Reviewed-by: Yannick FERTRE <yannick.fertre@st.com>
Tested-by: Yannick FERTRE <yannick.fertre@st.com>
Reviewed-by: Ludovic BARRE <ludovic.barre@st.com>
---
 .../devicetree/bindings/watchdog/st,stm32-iwdg.txt        | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/st,stm32-iwdg.txt

diff --git a/Documentation/devicetree/bindings/watchdog/st,stm32-iwdg.txt b/Documentation/devicetree/bindings/watchdog/st,stm32-iwdg.txt
new file mode 100644
index 0000000..9c6936b
--- /dev/null
+++ b/Documentation/devicetree/bindings/watchdog/st,stm32-iwdg.txt
@@ -0,0 +1,15 @@
+STM32 Independent WatchDoG (IWDG)
+---------------------------------
+
+Required properties:
+- compatible: "st,stm32-iwdg".
+- reg: physical base address and length of the registers set for the device;
+- clocks: Must contain a single entry describing the clock input
+
+Example:
+
+iwdg@40003000 {
+	compatible = "st,stm32-iwdg";
+	reg = <0x40003000 0x400>;
+	clocks = <&clk_lsi>;
+};
-- 
1.9.1

[PATCH v1 2/5] drivers: watchdog: Add STM32 IWDG driver

[Yannick Fertre]

This patch adds IWDG (Independent WatchDoG) support for STM32 platform.

Change-Id: Iab218745fc25566f12558fae7f52e2f8c21db74e
Signed-off-by: Yannick FERTRE <yannick.fertre-qxv4g6HH51o@public.gmane.org>
Tested-by: Yannick FERTRE <yannick.fertre-qxv4g6HH51o@public.gmane.org>
Reviewed-by: Ludovic BARRE <ludovic.barre-qxv4g6HH51o@public.gmane.org>
---
 drivers/watchdog/Kconfig      |  11 ++
 drivers/watchdog/Makefile     |   1 +
 drivers/watchdog/stm32_iwdg.c | 289 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 301 insertions(+)
 create mode 100644 drivers/watchdog/stm32_iwdg.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 52a70ee..d9745a5 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -744,6 +744,17 @@ config ZX2967_WATCHDOG
 	  To compile this driver as a module, choose M here: the
 	  module will be called zx2967_wdt.
 
+config STM32_WATCHDOG
+	tristate "STM32 Independent WatchDoG (IWDG) support"
+	depends on ARCH_STM32
+	select WATCHDOG_CORE
+	default y
+	help
+	  Say Y here to include Watchdog timer support.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called stm32_iwdg.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index a2126e2..a35e423 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -84,6 +84,7 @@ 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
+obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c
new file mode 100644
index 0000000..507dfc4
--- /dev/null
+++ b/drivers/watchdog/stm32_iwdg.c
@@ -0,0 +1,289 @@
+/*
+ * Driver for STM32 Independent Watchdog
+ *
+ * Copyright (C) Yannick Fertre 2017
+ * Author: Yannick Fertre <yannick.fertre-qxv4g6HH51o@public.gmane.org>
+ *
+ * This driver is based on tegra_wdt.c
+ *
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+/* minimum watchdog trigger timeout, in seconds */
+#define MIN_WDT_TIMEOUT	1
+
+/* IWDG registers */
+#define IWDG_KR		0x00 /* Key register */
+#define IWDG_PR		0x04 /* Prescaler Register */
+#define IWDG_RLR	0x08 /* ReLoad Register */
+#define IWDG_SR		0x0C /* Status Register */
+#define IWDG_WINR	0x10 /* Windows Register */
+
+/* IWDG_KR register bit mask */
+#define KR_KEY_RELOAD	0xAAAA /* reload counter enable */
+#define KR_KEY_ENABLE	0xCCCC /* peripheral enable */
+#define KR_KEY_EWA	0x5555 /* write access enable */
+#define KR_KEY_DWA	0x0000 /* write access disable */
+
+/* IWDG_PR register bit values */
+#define PR_4    0x00 /* prescaler set to 4 */
+#define PR_8    0x01 /* prescaler set to 8 */
+#define PR_16   0x02 /* prescaler set to 16 */
+#define PR_32   0x03 /* prescaler set to 32 */
+#define PR_64   0x04 /* prescaler set to 64 */
+#define PR_128  0x05 /* prescaler set to 128 */
+#define PR_256	0x06 /* prescaler set to 256 */
+
+/* IWDG_RLR register values */
+#define RLR_MAX		0xFFF /* max value supported by reload register */
+
+/* IWDG_SR register bit mask */
+#define FLAG_PVU	BIT(0) /* Watchdog prescaler value update */
+#define FLAG_RVU	BIT(1) /* Watchdog counter reload value update */
+
+/* set timeout to 100000 us */
+#define TIMEOUT_US	100000
+#define SLEEP_US	1000
+
+struct stm32_iwdg {
+	struct watchdog_device	wdd;
+	struct device		*dev;
+	void __iomem		*regs;
+	struct clk		*clk;
+	unsigned int		rate;
+};
+
+static int heartbeat = MIN_WDT_TIMEOUT;
+module_param(heartbeat, int, 0x0);
+MODULE_PARM_DESC(heartbeat,
+		 "Watchdog heartbeats in seconds. (default = "
+		 __MODULE_STRING(WDT_HEARTBEAT) ")");
+
+static inline u32 reg_read(void __iomem *base, u32 reg)
+{
+	return readl_relaxed(base + reg);
+}
+
+static inline void reg_write(void __iomem *base, u32 reg, u32 val)
+{
+	writel_relaxed(val, base + reg);
+}
+
+static int stm32_iwdg_start(struct watchdog_device *wdd)
+{
+	struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
+	u32 val = FLAG_PVU | FLAG_RVU;
+	u32 reload;
+	int ret;
+
+	dev_dbg(wdt->dev, "%s\n", __func__);
+
+	/* prescaler fixed to 256 */
+	reload = (wdd->timeout * wdt->rate) / 256;
+	if (reload > RLR_MAX + 1) {
+		dev_err(wdt->dev,
+			"Watchdog doesn't support reload value: %d\n", reload);
+		return -EINVAL;
+	}
+
+	/* enable watchdog */
+	reg_write(wdt->regs, IWDG_KR, KR_KEY_ENABLE);
+
+	/* set prescaler & reload registers */
+	reg_write(wdt->regs, IWDG_KR, KR_KEY_EWA);
+	reg_write(wdt->regs, IWDG_PR, PR_256); /* prescaler fix to 256 */
+	reg_write(wdt->regs, IWDG_RLR, reload - 1);
+
+	/* wait for the registers to be updated (max 100ms) */
+	ret = readl_relaxed_poll_timeout(wdt->regs + IWDG_SR, val,
+					 !(val & (FLAG_PVU | FLAG_RVU)),
+					 SLEEP_US, TIMEOUT_US);
+	if (ret) {
+		dev_err(wdt->dev,
+			"Fail to set prescaler or reload registers\n");
+		return -EINVAL;
+	}
+
+	/* reload watchdog */
+	reg_write(wdt->regs, IWDG_KR, KR_KEY_RELOAD);
+
+	return 0;
+}
+
+static int stm32_iwdg_stop(struct watchdog_device *wdd)
+{
+	struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
+
+	if (watchdog_active(wdd)) {
+		dev_err(wdt->dev,
+			"Watchdog can't be stopped once started(no way out)\n");
+		return -EPERM;
+	}
+
+	return 0;
+}
+
+static int stm32_iwdg_ping(struct watchdog_device *wdd)
+{
+	struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
+
+	dev_dbg(wdt->dev, "%s\n", __func__);
+
+	reg_write(wdt->regs, IWDG_KR, KR_KEY_RELOAD);
+
+	return 0;
+}
+
+static int stm32_iwdg_set_timeout(struct watchdog_device *wdd,
+				  unsigned int timeout)
+{
+	struct stm32_iwdg *wdt = watchdog_get_drvdata(wdd);
+
+	dev_dbg(wdt->dev, "%s timeout: %d sec\n", __func__, timeout);
+
+	wdd->timeout = timeout;
+
+	if (watchdog_active(wdd))
+		return stm32_iwdg_start(wdd);
+
+	return 0;
+}
+
+static const struct watchdog_info stm32_iwdg_info = {
+	.options	= WDIOF_SETTIMEOUT |
+			  WDIOF_MAGICCLOSE |
+			  WDIOF_KEEPALIVEPING,
+	.identity	= "STM32 Independent Watchdog",
+};
+
+static struct watchdog_ops stm32_iwdg_ops = {
+	.owner		= THIS_MODULE,
+	.start		= stm32_iwdg_start,
+	.stop		= stm32_iwdg_stop,
+	.ping		= stm32_iwdg_ping,
+	.set_timeout	= stm32_iwdg_set_timeout,
+};
+
+static int stm32_iwdg_probe(struct platform_device *pdev)
+{
+	struct watchdog_device *wdd;
+	struct stm32_iwdg *wdt;
+	struct resource *res;
+	void __iomem *regs;
+	struct clk *clk;
+	int max_wdt_timeout;
+	int ret;
+
+	/* This is the timer base. */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(regs)) {
+		dev_err(&pdev->dev, "Could not get resource\n");
+		return PTR_ERR(regs);
+	}
+
+	clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "Unable to get clock\n");
+		return PTR_ERR(clk);
+	}
+
+	ret = clk_prepare_enable(clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to prepare clock %p\n", clk);
+		return ret;
+	}
+
+	/*
+	 * Allocate our watchdog driver data, which has the
+	 * struct watchdog_device nested within it.
+	 */
+	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	/* Initialize struct stm32_iwdg. */
+	wdt->regs = regs;
+	wdt->dev = &pdev->dev;
+	wdt->clk = clk;
+	/*
+	 * iwdg is clocked by its own dedicated low-speed clock (LSI)
+	 * at 32khz.
+	 */
+	wdt->rate = 32 * 1024;
+
+	/* get max timeout & set heartbeat */
+	max_wdt_timeout = ((RLR_MAX + 1) * 256) / wdt->rate;
+	heartbeat = max_wdt_timeout;
+
+	/* Initialize struct watchdog_device. */
+	wdd = &wdt->wdd;
+	wdd->timeout = heartbeat;
+	wdd->info = &stm32_iwdg_info;
+	wdd->ops = &stm32_iwdg_ops;
+	wdd->min_timeout = MIN_WDT_TIMEOUT;
+	wdd->max_timeout = max_wdt_timeout;
+	watchdog_set_drvdata(wdd, wdt);
+	watchdog_set_nowayout(wdd, true);
+
+	ret = watchdog_register_device(wdd);
+	if (ret) {
+		dev_err(&pdev->dev,
+			"failed to register watchdog device\n");
+		goto err;
+	}
+
+	platform_set_drvdata(pdev, wdt);
+
+	dev_info(&pdev->dev,
+		 "initialized (heartbeat = %d sec)\n", heartbeat);
+	return 0;
+
+err:
+	clk_disable_unprepare(clk);
+	return ret;
+}
+
+static int stm32_iwdg_remove(struct platform_device *pdev)
+{
+	struct stm32_iwdg *wdt = platform_get_drvdata(pdev);
+
+	watchdog_unregister_device(&wdt->wdd);
+	clk_disable_unprepare(wdt->clk);
+
+	dev_info(&pdev->dev, "removed watchdog device\n");
+	return 0;
+}
+
+static const struct of_device_id stm32_iwdg_of_match[] = {
+	{ .compatible = "st,stm32-iwdg" },
+	{ /* end node */ }
+};
+MODULE_DEVICE_TABLE(of, stm32_iwdg_of_match);
+
+static struct platform_driver stm32_iwdg_driver = {
+	.probe		= stm32_iwdg_probe,
+	.remove		= stm32_iwdg_remove,
+	.driver = {
+		.name	= "iwdg",
+		.of_match_table = stm32_iwdg_of_match,
+	},
+};
+module_platform_driver(stm32_iwdg_driver);
+
+MODULE_AUTHOR("Yannick Fertre <yannick.fertre-qxv4g6HH51o@public.gmane.org>");
+MODULE_DESCRIPTION("STMicroelectronics STM32 Independent Watchdog Driver");
+MODULE_LICENSE("GPL v2");
-- 
1.9.1

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[PATCH v1 3/5] ARM: dts: stm32ap: Add watchdog support for STM32F429 SoC

[Yannick Fertre]

Signed-off-by: Yannick FERTRE <yannick.fertre@st.com>
---
 arch/arm/boot/dts/stm32f429.dtsi | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/stm32f429.dtsi b/arch/arm/boot/dts/stm32f429.dtsi
index ee0da97..148273b 100644
--- a/arch/arm/boot/dts/stm32f429.dtsi
+++ b/arch/arm/boot/dts/stm32f429.dtsi
@@ -65,7 +65,7 @@
 			clock-frequency = <32768>;
 		};
 
-		clk-lsi {
+		clk_lsi: clk-lsi {
 			#clock-cells = <0>;
 			compatible = "fixed-clock";
 			clock-frequency = <32000>;
@@ -812,6 +812,13 @@
 			clocks = <&rcc 0 STM32F4_AHB2_CLOCK(RNG)>;
 
 		};
+
+		iwdg: iwdg@40003000 {
+			compatible = "st,stm32-iwdg";
+			reg = <0x40003000 0x400>;
+			clocks = <&clk_lsi>;
+			status = "disabled";
+		};
 	};
 };
 
-- 
1.9.1

Re: [PATCH v1 3/5] ARM: dts: stm32ap: Add watchdog support for STM32F429 SoC

[Alexandre Torgue]

Hi

On 03/22/2017 02:36 PM, Yannick Fertre wrote:
> Signed-off-by: Yannick FERTRE <yannick.fertre@st.com>
> ---

Please add a commit message, and change commit header as following:

ARM: dts: stm32: ...

>  arch/arm/boot/dts/stm32f429.dtsi | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/stm32f429.dtsi b/arch/arm/boot/dts/stm32f429.dtsi
> index ee0da97..148273b 100644
> --- a/arch/arm/boot/dts/stm32f429.dtsi
> +++ b/arch/arm/boot/dts/stm32f429.dtsi
> @@ -65,7 +65,7 @@
>  			clock-frequency = <32768>;
>  		};
>
> -		clk-lsi {
> +		clk_lsi: clk-lsi {
>  			#clock-cells = <0>;
>  			compatible = "fixed-clock";
>  			clock-frequency = <32000>;
> @@ -812,6 +812,13 @@
>  			clocks = <&rcc 0 STM32F4_AHB2_CLOCK(RNG)>;
>
>  		};
> +
> +		iwdg: iwdg@40003000 {
Please try to keep nodes ordered.

> +			compatible = "st,stm32-iwdg";
> +			reg = <0x40003000 0x400>;
> +			clocks = <&clk_lsi>;
> +			status = "disabled";
> +		};
>  	};
>  };
>
>

[PATCH v1 4/5] ARM: dts: stm32ap: Add watchdog support for STM32F429 eval board

[Yannick Fertre]

Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
---
 arch/arm/boot/dts/stm32429i-eval.dts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/boot/dts/stm32429i-eval.dts b/arch/arm/boot/dts/stm32429i-eval.dts
index 3c99466..aab81ed 100644
--- a/arch/arm/boot/dts/stm32429i-eval.dts
+++ b/arch/arm/boot/dts/stm32429i-eval.dts
@@ -181,3 +181,7 @@
 	pinctrl-names = "default";
 	status = "okay";
 };
+
+&iwdg {
+	status = "okay";
+};
-- 
1.9.1

Re: [PATCH v1 4/5] ARM: dts: stm32ap: Add watchdog support for STM32F429 eval board

[Alexandre Torgue]

Hi

On 03/22/2017 02:36 PM, Yannick Fertre wrote:
> Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
> ---

Please add a commit message and change commit header as following:

ARM: dts: stm32: .....


>  arch/arm/boot/dts/stm32429i-eval.dts | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/arch/arm/boot/dts/stm32429i-eval.dts b/arch/arm/boot/dts/stm32429i-eval.dts
> index 3c99466..aab81ed 100644
> --- a/arch/arm/boot/dts/stm32429i-eval.dts
> +++ b/arch/arm/boot/dts/stm32429i-eval.dts
> @@ -181,3 +181,7 @@
>  	pinctrl-names = "default";
>  	status = "okay";
>  };
> +
> +&iwdg {
> +	status = "okay";
> +};
>

[PATCH v1 5/5] ARM: configs: Add watchdog support in STM32 defconfig

[Yannick Fertre]

Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
---
 arch/arm/configs/stm32_defconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/configs/stm32_defconfig b/arch/arm/configs/stm32_defconfig
index a9d8e3c..83afa73 100644
--- a/arch/arm/configs/stm32_defconfig
+++ b/arch/arm/configs/stm32_defconfig
@@ -48,6 +48,7 @@ CONFIG_SERIAL_STM32=y
 CONFIG_SERIAL_STM32_CONSOLE=y
 # CONFIG_HW_RANDOM is not set
 # CONFIG_HWMON is not set
+CONFIG_WATCHDOG=y
 CONFIG_REGULATOR=y
 CONFIG_REGULATOR_FIXED_VOLTAGE=y
 # CONFIG_USB_SUPPORT is not set
-- 
1.9.1