Re: [PATCH V2 8/8] watchdog: stpmic1: add stpmic1 watchdog driver
From: Guenter Roeck
Date: Fri Sep 07 2018 - 09:48:07 EST
On 09/07/2018 05:59 AM, Pascal PAILLET-LME wrote:
From: pascal paillet <p.paillet@xxxxxx>
The stpmic1 PMIC embeds a watchdog which is disabled by default. As soon
as the watchdog is started, it must be refreshed periodically otherwise
the PMIC goes off.
Signed-off-by: pascal paillet <p.paillet@xxxxxx>
---
changes in v2:
* the hardware component has been renamed from stpmu1 to stpmic1 !
* change headers
* handle remarks from Guenter
Hmm ... as if I would remember what those were.
* fix set timeout
drivers/watchdog/Kconfig | 12 ++++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/stpmic1_wdt.c | 130 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 143 insertions(+)
create mode 100644 drivers/watchdog/stpmic1_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 9af07fd..11c5937 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -796,6 +796,18 @@ config STM32_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called stm32_iwdg.
+config STPMIC1_WATCHDOG
+ tristate "STPMIC1 PMIC watchdog support"
+ depends on MFD_STPMIC1
+ select WATCHDOG_CORE
+ help
+ Say Y here to include watchdog support embedded into STPMIC1 PMIC.
+ If the watchdog timer expires, stpmic1 shut-down all its power
+ supplies.
+
+ To compile this driver as a module, choose M here: the
+ module will be called spmic1_wdt.
+
config UNIPHIER_WATCHDOG
tristate "UniPhier watchdog support"
depends on ARCH_UNIPHIER || COMPILE_TEST
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 1d3c6b0..a898d8f 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -216,3 +216,4 @@ obj-$(CONFIG_ZIIRAVE_WATCHDOG) += ziirave_wdt.o
obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o
obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o
+obj-$(CONFIG_STPMIC1_WATCHDOG) += stpmic1_wdt.o
diff --git a/drivers/watchdog/stpmic1_wdt.c b/drivers/watchdog/stpmic1_wdt.c
new file mode 100644
index 0000000..391e544
--- /dev/null
+++ b/drivers/watchdog/stpmic1_wdt.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) STMicroelectronics 2018
+// Author: Pascal Paillet <p.paillet@xxxxxx> for STMicroelectronics.
+ > +#include <linux/kernel.h>
+#include <linux/mfd/stpmic1.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/reboot.h>
+#include <linux/slab.h>
+#include <linux/watchdog.h>
+
+/* WATCHDOG CONTROL REGISTER bit */
+#define WDT_START BIT(0)
+#define WDT_PING BIT(1)
+#define WDT_START_MASK BIT(0)
+#define WDT_PING_MASK BIT(1)
+
+#define PMIC_WDT_MIN_TIMEOUT 1
+#define PMIC_WDT_MAX_TIMEOUT 256
+
+struct stpmic1_wdt {
+ struct stpmic1_dev *pmic;
+ struct watchdog_device wdtdev;
+};
+
+static int pmic_wdt_start(struct watchdog_device *wdd)
+{
+ struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ return regmap_update_bits(wdt->pmic->regmap,
+ WCHDG_CR, WDT_START_MASK, WDT_START);
+}
+
+static int pmic_wdt_stop(struct watchdog_device *wdd)
+{
+ struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ return regmap_update_bits(wdt->pmic->regmap,
+ WCHDG_CR, WDT_START_MASK, ~WDT_START);
+}
+
+static int pmic_wdt_ping(struct watchdog_device *wdd)
+{
+ struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ return regmap_update_bits(wdt->pmic->regmap,
+ WCHDG_CR, WDT_PING_MASK, WDT_PING);
+}
+
+static int pmic_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ return regmap_write(wdt->pmic->regmap, WCHDG_TIMER_CR, timeout - 1);
What happens if the configured timeout is 1 ? Does that translate to a 1-second
timeout ?
This function also has to set wdd->timeout.
+}
+
+static const struct watchdog_info pmic_watchdog_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
No WDIOF_MAGICCLOSE ?
+ .identity = "STPMIC1 PMIC Watchdog",
+};
+
+static const struct watchdog_ops pmic_watchdog_ops = {
+ .owner = THIS_MODULE,
+ .start = pmic_wdt_start,
+ .stop = pmic_wdt_stop,
+ .ping = pmic_wdt_ping,
+ .set_timeout = pmic_wdt_set_timeout,
+};
+
+static int pmic_wdt_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct stpmic1_dev *pmic;
+ struct stpmic1_wdt *wdt;
+
+ if (!pdev->dev.parent)
+ return -EINVAL;
+
+ pmic = dev_get_drvdata(pdev->dev.parent);
+ if (!pmic)
+ return -EINVAL;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(struct stpmic1_wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ wdt->pmic = pmic;
+
+ wdt->wdtdev.info = &pmic_watchdog_info;
+ wdt->wdtdev.ops = &pmic_watchdog_ops;
+ wdt->wdtdev.min_timeout = PMIC_WDT_MIN_TIMEOUT;
+ wdt->wdtdev.max_timeout = PMIC_WDT_MAX_TIMEOUT;
+ wdt->wdtdev.timeout = PMIC_WDT_MIN_TIMEOUT;
Are you sure about that ? A timeout of 1 second may be a cause for unexpected
reboots if user space is busy. Personally I find it better to set a larger
default and let userspace configure a tighter value if so desired.
Also,
watchdog_init_timeout(&wdt->wdtdev, 0, &pdev->dev);
might be desirable if you want to be able to specify the timeout in the
devicetree file.
+
+ wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
+
+ watchdog_set_drvdata(&wdt->wdtdev, wdt);
+ dev_set_drvdata(&pdev->dev, wdt);
Unless I am missing something this should not be needed.
+
+ ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdtdev);
+ if (ret)
+ return ret;
+
+ dev_dbg(wdt->pmic->dev, "PMIC Watchdog driver probed\n");
+ return 0;
+}
+
+static const struct of_device_id of_pmic_wdt_match[] = {
+ { .compatible = "st,stpmic1-wdt" },
+ { },
+};
+
+MODULE_DEVICE_TABLE(of, of_pmic_wdt_match);
+
+static struct platform_driver stpmic1_wdt_driver = {
+ .probe = pmic_wdt_probe,
+ .driver = {
+ .name = "stpmic1-wdt",
+ .of_match_table = of_pmic_wdt_match,
+ },
+};
+module_platform_driver(stpmic1_wdt_driver);
+
+MODULE_DESCRIPTION("Watchdog driver for STPMIC1 device");
+MODULE_AUTHOR("Pascal Paillet");
+MODULE_LICENSE("GPL v2");