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Subject[PATCH v13 8/8] watchdog: bd70528: Initial support for ROHM BD70528 watchdog block
Initial support for watchdog block included in ROHM BD70528
power management IC.

Configurations for low power states are still to be checked.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
---
Changelog v13
- Moved WDT enable/disable code from MFD to WDT as was (strongly) suggested
by Lee Jones

Changelog v12
- No functional changes
- Small styling fixes

drivers/watchdog/Kconfig | 12 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/bd70528_wdt.c | 290 +++++++++++++++++++++++++++++++++
3 files changed, 303 insertions(+)
create mode 100644 drivers/watchdog/bd70528_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 242eea859637..a00bf649d7f0 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -90,6 +90,18 @@ config SOFT_WATCHDOG_PRETIMEOUT
watchdog. Be aware that governors might affect the watchdog because it
is purely software, e.g. the panic governor will stall it!

+config BD70528_WATCHDOG
+ tristate "ROHM BD70528 PMIC Watchdog"
+ depends on MFD_ROHM_BD70528
+ select WATCHDOG_CORE
+ help
+ Support for the watchdog in the ROHM BD70528 PMIC. Watchdog trigger
+ cause system reset.
+
+ Say Y here to include support for the ROHM BD70528 watchdog.
+ Alternatively say M to compile the driver as a module,
+ which will be called bd70528_wdt.
+
config DA9052_WATCHDOG
tristate "Dialog DA9052 Watchdog"
depends on PMIC_DA9052 || COMPILE_TEST
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index ba930e464657..3985922c440a 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -205,6 +205,7 @@ obj-$(CONFIG_WATCHDOG_SUN4V) += sun4v_wdt.o
obj-$(CONFIG_XEN_WDT) += xen_wdt.o

# Architecture Independent
+obj-$(CONFIG_BD70528_WATCHDOG) += bd70528_wdt.o
obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o
obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o
obj-$(CONFIG_DA9062_WATCHDOG) += da9062_wdt.o
diff --git a/drivers/watchdog/bd70528_wdt.c b/drivers/watchdog/bd70528_wdt.c
new file mode 100644
index 000000000000..b0152fef4fc7
--- /dev/null
+++ b/drivers/watchdog/bd70528_wdt.c
@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 ROHM Semiconductors
+// ROHM BD70528MWV watchdog driver
+
+#include <linux/bcd.h>
+#include <linux/kernel.h>
+#include <linux/mfd/rohm-bd70528.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/watchdog.h>
+
+/*
+ * Max time we can set is 1 hour, 59 minutes and 59 seconds
+ * and Minimum time is 1 second
+ */
+#define WDT_MAX_MS ((2 * 60 * 60 - 1) * 1000)
+#define WDT_MIN_MS 1000
+#define DEFAULT_TIMEOUT 60
+
+#define WD_CTRL_MAGIC1 0x55
+#define WD_CTRL_MAGIC2 0xAA
+
+struct wdtbd70528 {
+ struct device *dev;
+ struct regmap *regmap;
+ struct rohm_regmap_dev *mfd;
+ struct watchdog_device wdt;
+};
+
+/**
+ * bd70528_wdt_set - arm or disarm watchdog timer
+ *
+ * @data: device data for the PMIC instance we want to operate on
+ * @enable: new state of WDT. zero to disable, non zero to enable
+ * @old_state: previous state of WDT will be filled here
+ *
+ * Arm or disarm WDT on BD70528 PMIC. Expected to be called only by
+ * BD70528 RTC and BD70528 WDT drivers. The rtc_timer_lock must be taken
+ * by calling bd70528_wdt_lock before calling bd70528_wdt_set.
+ */
+int bd70528_wdt_set(struct rohm_regmap_dev *data, int enable, int *old_state)
+{
+ int ret, i;
+ unsigned int tmp;
+ struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
+ chip);
+ u8 wd_ctrl_arr[3] = { WD_CTRL_MAGIC1, WD_CTRL_MAGIC2, 0 };
+ u8 *wd_ctrl = &wd_ctrl_arr[2];
+
+ ret = regmap_read(bd70528->chip.regmap, BD70528_REG_WDT_CTRL, &tmp);
+ if (ret)
+ return ret;
+
+ *wd_ctrl = (u8)tmp;
+
+ if (old_state) {
+ if (*wd_ctrl & BD70528_MASK_WDT_EN)
+ *old_state |= BD70528_WDT_STATE_BIT;
+ else
+ *old_state &= ~BD70528_WDT_STATE_BIT;
+ if ((!enable) == (!(*old_state & BD70528_WDT_STATE_BIT)))
+ return 0;
+ }
+
+ if (enable) {
+ if (*wd_ctrl & BD70528_MASK_WDT_EN)
+ return 0;
+ *wd_ctrl |= BD70528_MASK_WDT_EN;
+ } else {
+ if (*wd_ctrl & BD70528_MASK_WDT_EN)
+ *wd_ctrl &= ~BD70528_MASK_WDT_EN;
+ else
+ return 0;
+ }
+
+ for (i = 0; i < 3; i++) {
+ ret = regmap_write(bd70528->chip.regmap, BD70528_REG_WDT_CTRL,
+ wd_ctrl_arr[i]);
+ if (ret)
+ return ret;
+ }
+
+ ret = regmap_read(bd70528->chip.regmap, BD70528_REG_WDT_CTRL, &tmp);
+ if ((tmp & BD70528_MASK_WDT_EN) != (*wd_ctrl & BD70528_MASK_WDT_EN)) {
+ dev_err(bd70528->chip.dev,
+ "Watchdog ctrl mismatch (hw) 0x%x (set) 0x%x\n",
+ tmp, *wd_ctrl);
+ ret = -EIO;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(bd70528_wdt_set);
+
+/**
+ * bd70528_wdt_lock - take WDT lock
+ *
+ * @bd70528: device data for the PMIC instance we want to operate on
+ *
+ * Lock WDT for arming/disarming in order to avoid race condition caused
+ * by WDT state changes initiated by WDT and RTC drivers.
+ */
+void bd70528_wdt_lock(struct rohm_regmap_dev *data)
+{
+ struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
+ chip);
+
+ mutex_lock(&bd70528->rtc_timer_lock);
+}
+EXPORT_SYMBOL(bd70528_wdt_lock);
+
+/**
+ * bd70528_wdt_unlock - unlock WDT lock
+ *
+ * @bd70528: device data for the PMIC instance we want to operate on
+ *
+ * Unlock WDT lock which has previously been taken by call to
+ * bd70528_wdt_lock.
+ */
+void bd70528_wdt_unlock(struct rohm_regmap_dev *data)
+{
+ struct bd70528_data *bd70528 = container_of(data, struct bd70528_data,
+ chip);
+
+ mutex_unlock(&bd70528->rtc_timer_lock);
+}
+EXPORT_SYMBOL(bd70528_wdt_unlock);
+
+static int bd70528_wdt_set_locked(struct wdtbd70528 *w, int enable)
+{
+ return bd70528_wdt_set(w->mfd, enable, NULL);
+}
+
+static int bd70528_wdt_change(struct wdtbd70528 *w, int enable)
+{
+ int ret;
+
+ bd70528_wdt_lock(w->mfd);
+ ret = bd70528_wdt_set_locked(w, enable);
+ bd70528_wdt_unlock(w->mfd);
+
+ return ret;
+}
+
+static int bd70528_wdt_start(struct watchdog_device *wdt)
+{
+ struct wdtbd70528 *w = watchdog_get_drvdata(wdt);
+
+ dev_dbg(w->dev, "WDT ping...\n");
+ return bd70528_wdt_change(w, 1);
+}
+
+static int bd70528_wdt_stop(struct watchdog_device *wdt)
+{
+ struct wdtbd70528 *w = watchdog_get_drvdata(wdt);
+
+ dev_dbg(w->dev, "WDT stopping...\n");
+ return bd70528_wdt_change(w, 0);
+}
+
+static int bd70528_wdt_set_timeout(struct watchdog_device *wdt,
+ unsigned int timeout)
+{
+ unsigned int hours;
+ unsigned int minutes;
+ unsigned int seconds;
+ int ret;
+ struct wdtbd70528 *w = watchdog_get_drvdata(wdt);
+
+ seconds = timeout;
+ hours = timeout / (60 * 60);
+ /* Maximum timeout is 1h 59m 59s => hours is 1 or 0 */
+ if (hours)
+ seconds -= (60 * 60);
+ minutes = seconds / 60;
+ seconds = seconds % 60;
+
+ bd70528_wdt_lock(w->mfd);
+
+ ret = bd70528_wdt_set_locked(w, 0);
+ if (ret)
+ goto out_unlock;
+
+ ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_HOUR,
+ BD70528_MASK_WDT_HOUR, hours);
+ if (ret) {
+ dev_err(w->dev, "Failed to set WDT hours\n");
+ goto out_en_unlock;
+ }
+ ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_MINUTE,
+ BD70528_MASK_WDT_MINUTE, bin2bcd(minutes));
+ if (ret) {
+ dev_err(w->dev, "Failed to set WDT minutes\n");
+ goto out_en_unlock;
+ }
+ ret = regmap_update_bits(w->regmap, BD70528_REG_WDT_SEC,
+ BD70528_MASK_WDT_SEC, bin2bcd(seconds));
+ if (ret)
+ dev_err(w->dev, "Failed to set WDT seconds\n");
+ else
+ dev_dbg(w->dev, "WDT tmo set to %u\n", timeout);
+
+out_en_unlock:
+ ret = bd70528_wdt_set_locked(w, 1);
+out_unlock:
+ bd70528_wdt_unlock(w->mfd);
+
+ return ret;
+}
+
+static const struct watchdog_info bd70528_wdt_info = {
+ .identity = "bd70528-wdt",
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops bd70528_wdt_ops = {
+ .start = bd70528_wdt_start,
+ .stop = bd70528_wdt_stop,
+ .set_timeout = bd70528_wdt_set_timeout,
+};
+
+static int bd70528_wdt_probe(struct platform_device *pdev)
+{
+ struct rohm_regmap_dev *bd70528;
+ struct wdtbd70528 *w;
+ int ret;
+ unsigned int reg;
+
+ bd70528 = dev_get_drvdata(pdev->dev.parent);
+ if (!bd70528) {
+ dev_err(&pdev->dev, "No MFD driver data\n");
+ return -EINVAL;
+ }
+ w = devm_kzalloc(&pdev->dev, sizeof(*w), GFP_KERNEL);
+ if (!w)
+ return -ENOMEM;
+
+ w->regmap = bd70528->regmap;
+ w->mfd = bd70528;
+ w->dev = &pdev->dev;
+
+ w->wdt.info = &bd70528_wdt_info;
+ w->wdt.ops = &bd70528_wdt_ops;
+ w->wdt.min_hw_heartbeat_ms = WDT_MIN_MS;
+ w->wdt.max_hw_heartbeat_ms = WDT_MAX_MS;
+ w->wdt.parent = pdev->dev.parent;
+ w->wdt.timeout = DEFAULT_TIMEOUT;
+ watchdog_set_drvdata(&w->wdt, w);
+ watchdog_init_timeout(&w->wdt, 0, pdev->dev.parent);
+
+ ret = bd70528_wdt_set_timeout(&w->wdt, w->wdt.timeout);
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to set the watchdog timeout\n");
+ return ret;
+ }
+
+ bd70528_wdt_lock(w->mfd);
+ ret = regmap_read(w->regmap, BD70528_REG_WDT_CTRL, &reg);
+ bd70528_wdt_unlock(w->mfd);
+
+ if (ret) {
+ dev_err(&pdev->dev, "Failed to get the watchdog state\n");
+ return ret;
+ }
+ if (reg & BD70528_MASK_WDT_EN) {
+ dev_dbg(&pdev->dev, "watchdog was running during probe\n");
+ set_bit(WDOG_HW_RUNNING, &w->wdt.status);
+ }
+
+ ret = devm_watchdog_register_device(&pdev->dev, &w->wdt);
+ if (ret < 0)
+ dev_err(&pdev->dev, "watchdog registration failed: %d\n", ret);
+
+ return ret;
+}
+
+static struct platform_driver bd70528_wdt = {
+ .driver = {
+ .name = "bd70528-wdt"
+ },
+ .probe = bd70528_wdt_probe,
+};
+
+module_platform_driver(bd70528_wdt);
+
+MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
+MODULE_DESCRIPTION("BD70528 watchdog driver");
+MODULE_LICENSE("GPL");
--
2.17.2

--
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~

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