The PM816 module is a versatile PMIC with many diverse functions
integrated, including, a watchdog.
This watchdog is subcomponent of the PON (Power On) peripheral,
in the same way as pwrkey/resin buttons.
It works with two timers (2-stages), the first one generates an
IRQ to the main SoC (APQ8016/MSM8916), the second one performs
the reset.
This driver expects the following device hierachy:
[pm8916]->[pm8916-pon]->[pm8916-wdt]
It uses the pm8916 regmap to access PM8916 registers.
Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxx>
---
drivers/watchdog/Kconfig | 8 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/pm8916_wdt.c | 177 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 186 insertions(+)
create mode 100644 drivers/watchdog/pm8916_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 2d64333..66bab61 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -847,6 +847,14 @@ config SPRD_WATCHDOG
Say Y here to include watchdog timer supported
by Spreadtrum system.
+config PM8916_WATCHDOG
+ tristate "QCOM pm8916 pmic watchdog"
+ depends on OF && MFD_SPMI_PMIC
+ select WATCHDOG_CORE
+ help
+ Say Y here to include support watchdog timer embedded into the
+ pm8916 module.
+
# X86 (i386 + ia64 + x86_64) Architecture
config ACQUIRE_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index f69cdff..cc90e72 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -92,6 +92,7 @@ obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o
obj-$(CONFIG_RTD119X_WATCHDOG) += rtd119x_wdt.o
obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o
+obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o
# X86 (i386 + ia64 + x86_64) Architecture
obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
diff --git a/drivers/watchdog/pm8916_wdt.c b/drivers/watchdog/pm8916_wdt.c
new file mode 100644
index 0000000..36f9763
--- /dev/null
+++ b/drivers/watchdog/pm8916_wdt.c
@@ -0,0 +1,177 @@
+/*
+ * Watchdog driver for QCOM PM8916
+ *
+ * Copyright (C) 2018 Loic Poulain, Linaro <loic.poulain@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <linux/regmap.h>
+
+#define PM8916_WDT_DEFAULT_TIMEOUT 32
+
+#define PON_PMIC_WD_RESET_S1_TIMER 0x54
+#define PON_PMIC_WD_RESET_S2_TIMER 0x55
+#define PON_PMIC_WD_RESET_S2_CTL 0x56
+#define PON_PMIC_WD_RESET_S2_CTL2 0x57
+#define PON_PMIC_WD_RESET_PET 0x58
+
+#define S2_RESET_EN_MASK BIT(7)
+#define S2_RESET_EN (1 << 7)
+
+#define WATCHDOG_PET_MASK BIT(0)
+
+struct pm8916_wdt {
+ struct device *dev;
+ struct regmap *regmap;
+ struct watchdog_device wdev;
+ u32 baseaddr;
+};
+
+static int pm8916_wdt_start(struct watchdog_device *wdev)
+{
+ struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
+
+ return regmap_update_bits(wdt->regmap,
+ wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
+ S2_RESET_EN_MASK, S2_RESET_EN);
+}
+
+static int pm8916_wdt_stop(struct watchdog_device *wdev)
+{
+ struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
+
+ return regmap_update_bits(wdt->regmap,
+ wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
+ S2_RESET_EN_MASK, 0);
+}
+
+static int pm8916_wdt_ping(struct watchdog_device *wdev)
+{
+ struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
+
+ return regmap_update_bits(wdt->regmap,
+ wdt->baseaddr + PON_PMIC_WD_RESET_PET,
+ WATCHDOG_PET_MASK, 1);
+}
+
+static int pm8916_wdt_set_timeout(struct watchdog_device *wdev,
+ unsigned int timeout)
+{
+ struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
+ int err;
+
+ wdev->timeout = timeout;
+
+ /* This is a two stages watchdog, set stage-1 timer generate an irq and
+ * stage-2 trigger the reset. In order to respect expected timeout, set
+ * stage-1 timer to timeout and stage-2 to 0.
+ */
+ err = regmap_write(wdt->regmap,
+ wdt->baseaddr + PON_PMIC_WD_RESET_S1_TIMER,
+ timeout);
+ if (err)
+ return err;
+
+ return regmap_write(wdt->regmap,
+ wdt->baseaddr + PON_PMIC_WD_RESET_S2_TIMER,
+ 0);
+}
+
+static const struct watchdog_info pm8916_wdt_ident = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+ .identity = "QCOM PM8916 PON WDT",
+};
+
+static const struct watchdog_ops pm8916_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = pm8916_wdt_start,
+ .stop = pm8916_wdt_stop,
+ .ping = pm8916_wdt_ping,
+ .set_timeout = pm8916_wdt_set_timeout,
+};
+
+static int pm8916_wdt_probe(struct platform_device *pdev)
+{
+ struct pm8916_wdt *wdt;
+ struct device *parent;
+ int err;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ wdt->dev = &pdev->dev;
+ parent = pdev->dev.parent;
+
+ /*
+ * The pm8916-pon-wdt is a child of the pon device, which is a child
+ * of the pm8916 mfd device. We want access to the pm8916 registers.
+ * Retrieve regmap from pm8916 (parent->parent) and base address
+ * from pm8916-pon (pon).
+ */
+ wdt->regmap = dev_get_regmap(parent->parent, NULL);
+ if (!wdt->regmap) {
+ dev_err(&pdev->dev, "failed to locate regmap\n");
+ return -ENODEV;
+ }
+
+ err = device_property_read_u32(parent, "reg", &wdt->baseaddr);
+ if (err) {
+ dev_err(&pdev->dev, "failed to get address\n");
+ return err;
+ }
+
+ /* Configure watchdog to hard-reset mode */
+ err = regmap_write(wdt->regmap,
+ wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL, 0x07);
+ if (err) {
+ dev_err(&pdev->dev, "failed configure watchdog\n");
+ return err;
+ }
+
+ wdt->wdev.info = &pm8916_wdt_ident,
+ wdt->wdev.ops = &pm8916_wdt_ops,
+ wdt->wdev.parent = &pdev->dev;
+ wdt->wdev.min_timeout = 1;
+ wdt->wdev.max_timeout = 127;
+ wdt->wdev.timeout = PM8916_WDT_DEFAULT_TIMEOUT;
+ watchdog_set_drvdata(&wdt->wdev, wdt);
+
+ pm8916_wdt_set_timeout(&wdt->wdev, wdt->wdev.timeout);
+
+ return watchdog_register_device(&wdt->wdev);
+}
+
+static const struct of_device_id pm8916_wdt_id_table[] = {
+ { .compatible = "qcom,pm8916-wdt" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, pm8916_wdt_id_table);
+
+static struct platform_driver pm8916_wdt_driver = {
+ .probe = pm8916_wdt_probe,
+ .driver = {
+ .name = "pm8916-wdt",
+ .of_match_table = of_match_ptr(pm8916_wdt_id_table),
+ },
+};
+module_platform_driver(pm8916_wdt_driver);
+
+MODULE_AUTHOR("Loic Poulain <loic.poulain@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Qualcomm pm8916 watchdog driver");
+MODULE_LICENSE("GPL v2");
--
2.7.4
