watchdog: Add pm8916 watchdog driver

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 hierarchy:
[pm8916]->[pm8916-pon]->[pm8916-wdt]

It uses the pm8916 regmap to access PM8916 registers.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 746759ec8960d5dd9ad064b28c3a75ae45606bd5..6dcd5603a3e48546e379b27477129710ee8552c4 100644 (file)
--- 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 f69cdff5ad7fbaf0d666a2d4e057553f603c11d5..cc90e723135eae8fc1fc7305710a92d3a0f57059 100644 (file)
--- 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 (file)
index 0000000..7f10041
--- /dev/null
+++ b/drivers/watchdog/pm8916_wdt.c
@@ -0,0 +1,211 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/property.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/watchdog.h>
+
+#define PON_INT_RT_STS                 0x10
+#define PMIC_WD_BARK_STS_BIT           BIT(6)
+
+#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 RESET_TYPE_WARM                        0x01
+#define RESET_TYPE_SHUTDOWN            0x04
+#define RESET_TYPE_HARD                        0x07
+
+#define PON_PMIC_WD_RESET_S2_CTL2      0x57
+#define S2_RESET_EN_BIT                        BIT(7)
+
+#define PON_PMIC_WD_RESET_PET          0x58
+#define WATCHDOG_PET_BIT               BIT(0)
+
+#define PM8916_WDT_DEFAULT_TIMEOUT     32
+#define PM8916_WDT_MIN_TIMEOUT         1
+#define PM8916_WDT_MAX_TIMEOUT         127
+
+struct pm8916_wdt {
+       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_BIT, S2_RESET_EN_BIT);
+}
+
+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_BIT, 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_BIT, WATCHDOG_PET_BIT);
+}
+
+static int pm8916_wdt_configure_timers(struct watchdog_device *wdev)
+{
+       struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
+       int err;
+
+       err = regmap_write(wdt->regmap,
+                          wdt->baseaddr + PON_PMIC_WD_RESET_S1_TIMER,
+                          wdev->timeout - wdev->pretimeout);
+       if (err)
+               return err;
+
+       return regmap_write(wdt->regmap,
+                           wdt->baseaddr + PON_PMIC_WD_RESET_S2_TIMER,
+                           wdev->pretimeout);
+}
+
+static int pm8916_wdt_set_timeout(struct watchdog_device *wdev,
+                                 unsigned int timeout)
+{
+       wdev->timeout = timeout;
+
+       return pm8916_wdt_configure_timers(wdev);
+}
+
+static int pm8916_wdt_set_pretimeout(struct watchdog_device *wdev,
+                                    unsigned int pretimeout)
+{
+       wdev->pretimeout = pretimeout;
+
+       return pm8916_wdt_configure_timers(wdev);
+}
+
+static irqreturn_t pm8916_wdt_isr(int irq, void *arg)
+{
+       struct pm8916_wdt *wdt = arg;
+       int err, sts;
+
+       err = regmap_read(wdt->regmap, wdt->baseaddr + PON_INT_RT_STS, &sts);
+       if (err)
+               return IRQ_HANDLED;
+
+       if (sts & PMIC_WD_BARK_STS_BIT)
+               watchdog_notify_pretimeout(&wdt->wdev);
+
+       return IRQ_HANDLED;
+}
+
+static const struct watchdog_info pm8916_wdt_ident = {
+       .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+       .identity = "QCOM PM8916 PON WDT",
+};
+
+static const struct watchdog_info pm8916_wdt_pt_ident = {
+       .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE |
+                  WDIOF_PRETIMEOUT,
+       .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,
+       .set_pretimeout = pm8916_wdt_set_pretimeout,
+};
+
+static int pm8916_wdt_probe(struct platform_device *pdev)
+{
+       struct pm8916_wdt *wdt;
+       struct device *parent;
+       int err, irq;
+
+       wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+       if (!wdt)
+               return -ENOMEM;
+
+       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 pm8916-pon address\n");
+               return err;
+       }
+
+       irq = platform_get_irq(pdev, 0);
+       if (irq > 0) {
+               if (devm_request_irq(&pdev->dev, irq, pm8916_wdt_isr, 0,
+                                    "pm8916_wdt", wdt))
+                       irq = 0;
+       }
+
+       /* Configure watchdog to hard-reset mode */
+       err = regmap_write(wdt->regmap,
+                          wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL,
+                          RESET_TYPE_HARD);
+       if (err) {
+               dev_err(&pdev->dev, "failed configure watchdog\n");
+               return err;
+       }
+
+       wdt->wdev.info = (irq > 0) ? &pm8916_wdt_pt_ident : &pm8916_wdt_ident,
+       wdt->wdev.ops = &pm8916_wdt_ops,
+       wdt->wdev.parent = &pdev->dev;
+       wdt->wdev.min_timeout = PM8916_WDT_MIN_TIMEOUT;
+       wdt->wdev.max_timeout = PM8916_WDT_MAX_TIMEOUT;
+       wdt->wdev.timeout = PM8916_WDT_DEFAULT_TIMEOUT;
+       wdt->wdev.pretimeout = 0;
+       watchdog_set_drvdata(&wdt->wdev, wdt);
+
+       watchdog_init_timeout(&wdt->wdev, 0, &pdev->dev);
+       pm8916_wdt_configure_timers(&wdt->wdev);
+
+       return devm_watchdog_register_device(&pdev->dev, &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@linaro.org>");
+MODULE_DESCRIPTION("Qualcomm pm8916 watchdog driver");
+MODULE_LICENSE("GPL v2");