[PATCH V2 3/4] watchdog: da9062: DA9062 watchdog driver

S Twiss
2015-05-14T16:54:11Z

From: S Twiss <stwiss.opensource@diasemi.com>

Add watchdog driver support for DA9062

Signed-off-by: Steve Twiss <stwiss.opensource@diasemi.com>

---

Changes in V2:
- Removed informational dev_info() 'installed watchdog' message
- Copyright headers GPL v2 (and later) match correct 'GPL' in MODULE_LICENSE
- Removed the explicit 300 msecs delay from the reset_watchdog_timer()
function and replaced it with a variable delay (depending on the
difference since the last ping). A debug message is used to catch the
multiple pings trying to break the 300 msecs protection barrier.
- Fix error paths for the functions da9062_wdt_update_timeout_register()
and da9062_wdt_stop()
- Add error paths in the probe() and correctly clean-up the registered
device if there is a problem after registration.

This patch applies against linux-next and v4.1-rc3

drivers/watchdog/Kconfig | 9 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/da9062_wdt.c | 288 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 298 insertions(+)
create mode 100644 drivers/watchdog/da9062_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index e5e7c55..dfdb6c6 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -96,6 +96,15 @@ config DA9063_WATCHDOG

This driver can be built as a module. The module name is da9063_wdt.

+config DA9062_WATCHDOG
+ tristate "Dialog DA9062 Watchdog"
+ depends on MFD_DA9062
+ select WATCHDOG_CORE
+ help
+ Support for the watchdog in the DA9062 PMIC.
+
+ This driver can be built as a module. The module name is da9062_wdt.
+
config GPIO_WATCHDOG
tristate "Watchdog device controlled through GPIO-line"
depends on OF_GPIO
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 5c19294..57ba815 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -179,6 +179,7 @@ obj-$(CONFIG_XEN_WDT) += xen_wdt.o
# Architecture Independent
obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o
obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o
+obj-$(CONFIG_DA9062_WATCHDOG) += da9062_wdt.o
obj-$(CONFIG_DA9063_WATCHDOG) += da9063_wdt.o
obj-$(CONFIG_GPIO_WATCHDOG) += gpio_wdt.o
obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
new file mode 100644
index 0000000..9e6c93b
--- /dev/null
+++ b/drivers/watchdog/da9062_wdt.c
@@ -0,0 +1,288 @@
+/*
+ * da9062_wdt.c - WDT device driver for DA9062
+ * Copyright (C) 2015 Dialog Semiconductor Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/jiffies.h>
+#include <linux/mfd/da9062/registers.h>
+#include <linux/mfd/da9062/core.h>
+#include <linux/regmap.h>
+#include <linux/of.h>
+
+static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
+#define DA9062_TWDSCALE_DISABLE 0
+#define DA9062_TWDSCALE_MIN 1
+#define DA9062_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)
+#define DA9062_WDT_MIN_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MIN]
+#define DA9062_WDT_MAX_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MAX]
+#define DA9062_WDG_DEFAULT_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MAX-1]
+#define DA9062_RESET_PROTECTION_MS 300
+
+struct da9062_watchdog {
+ struct da9062 *hw;
+ struct watchdog_device wdtdev;
+ unsigned long j_time_stamp;
+};
+
+static void da9062_set_window_start(struct da9062_watchdog *wdt)
+{
+ wdt->j_time_stamp = jiffies;
+}
+
+static void da9062_apply_window_protection(struct da9062_watchdog *wdt)
+{
+ unsigned long delay = msecs_to_jiffies(DA9062_RESET_PROTECTION_MS);
+ unsigned long timeout = wdt->j_time_stamp + delay;
+ unsigned long now = jiffies;
+ unsigned int diff_ms;
+
+ /* if time-limit has not elapsed then wait for remainder */
+ if (time_before(now, timeout)) {
+ diff_ms = jiffies_to_msecs(timeout-now);
+ dev_dbg(wdt->hw->dev,
+ "Kicked too quickly. Delaying %u msecs\n", diff_ms);
+ msleep(diff_ms);
+ }
+
+ return;
+}
+
+static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
+{
+ unsigned int i;
+
+ for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
+ if (wdt_timeout[i] >= secs)
+ return i;
+ }
+
+ return DA9062_TWDSCALE_MAX;
+}
+
+static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
+{
+ int ret;
+
+ da9062_apply_window_protection(wdt);
+
+ ret = regmap_update_bits(wdt->hw->regmap,
+ DA9062AA_CONTROL_F,
+ DA9062AA_WATCHDOG_MASK,
+ DA9062AA_WATCHDOG_MASK);
+
+ da9062_set_window_start(wdt);
+
+ return ret;
+}
+
+static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
+ unsigned int regval)
+{
+ struct da9062 *chip = wdt->hw;
+ int ret;
+
+ ret = da9062_reset_watchdog_timer(wdt);
+ if (ret) {
+ dev_err(chip->dev, "Failed to ping the watchdog (err = %d)\n",
+ ret);
+ return ret;
+ }
+
+ return regmap_update_bits(chip->regmap,
+ DA9062AA_CONTROL_D,
+ DA9062AA_TWDSCALE_MASK,
+ regval);
+}
+
+static int da9062_wdt_start(struct watchdog_device *wdd)
+{
+ struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+ unsigned int selector;
+ int ret;
+
+ selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
+ ret = da9062_wdt_update_timeout_register(wdt, selector);
+ if (ret)
+ dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
+ ret);
+
+ return ret;
+}
+
+static int da9062_wdt_stop(struct watchdog_device *wdd)
+{
+ struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+ int ret;
+
+ ret = da9062_reset_watchdog_timer(wdt);
+ if (ret) {
+ dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
+ ret);
+ return ret;
+ }
+
+ ret = regmap_update_bits(wdt->hw->regmap,
+ DA9062AA_CONTROL_D,
+ DA9062AA_TWDSCALE_MASK,
+ DA9062_TWDSCALE_DISABLE);
+ if (ret)
+ dev_alert(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
+ ret);
+
+ return ret;
+}
+
+static int da9062_wdt_ping(struct watchdog_device *wdd)
+{
+ struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+ int ret;
+
+ dev_dbg(wdt->hw->dev, "watchdog ping\n");
+
+ ret = da9062_reset_watchdog_timer(wdt);
+ if (ret)
+ dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
+ ret);
+
+ return ret;
+}
+
+static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+ unsigned int selector;
+ int ret;
+
+ selector = da9062_wdt_timeout_to_sel(timeout);
+ ret = da9062_wdt_update_timeout_register(wdt, selector);
+ if (ret)
+ dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
+ ret);
+ else
+ wdd->timeout = wdt_timeout[selector];
+
+ return ret;
+}
+
+/* E_WDG_WARN interrupt handler */
+static irqreturn_t da9062_wdt_wdg_warn_irq_handler(int irq, void *data)
+{
+ struct da9062_watchdog *wdt = data;
+
+ dev_notice(wdt->hw->dev, "Watchdog timeout warning trigger.\n");
+ return IRQ_HANDLED;
+}
+
+static const struct watchdog_info da9062_watchdog_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+ .identity = "DA9062 WDT",
+};
+
+static const struct watchdog_ops da9062_watchdog_ops = {
+ .owner = THIS_MODULE,
+ .start = da9062_wdt_start,
+ .stop = da9062_wdt_stop,
+ .ping = da9062_wdt_ping,
+ .set_timeout = da9062_wdt_set_timeout,
+};
+
+static int da9062_wdt_probe(struct platform_device *pdev)
+{
+ int ret;
+ struct da9062 *chip;
+ struct da9062_watchdog *wdt;
+ int irq;
+
+ chip = dev_get_drvdata(pdev->dev.parent);
+ if (!chip)
+ return -EINVAL;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ wdt->hw = chip;
+
+ wdt->wdtdev.info = &da9062_watchdog_info;
+ wdt->wdtdev.ops = &da9062_watchdog_ops;
+ wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
+ wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
+ wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
+ wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
+
+ watchdog_set_drvdata(&wdt->wdtdev, wdt);
+ dev_set_drvdata(&pdev->dev, wdt);
+
+ irq = platform_get_irq_byname(pdev, "WDG_WARN");
+ if (irq < 0) {
+ dev_err(wdt->hw->dev, "Failed to get IRQ.\n");
+ ret = irq;
+ goto error;
+ }
+
+ ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+ da9062_wdt_wdg_warn_irq_handler,
+ IRQF_TRIGGER_LOW | IRQF_ONESHOT | IRQF_SHARED,
+ "WDG_WARN", wdt);
+ if (ret) {
+ dev_err(wdt->hw->dev,
+ "Failed to request watchdog device IRQ.\n");
+ goto error;
+ }
+
+ ret = watchdog_register_device(&wdt->wdtdev);
+ if (ret < 0) {
+ dev_err(wdt->hw->dev,
+ "watchdog registration incomplete (%d)\n", ret);
+ goto error;
+ }
+
+ da9062_set_window_start(wdt);
+
+ ret = da9062_wdt_ping(&wdt->wdtdev);
+ if (ret < 0)
+ watchdog_unregister_device(&wdt->wdtdev);
+
+error:
+ return ret;
+}
+
+static int da9062_wdt_remove(struct platform_device *pdev)
+{
+ struct da9062_watchdog *wdt = dev_get_drvdata(&pdev->dev);
+
+ watchdog_unregister_device(&wdt->wdtdev);
+ return 0;
+}
+
+static struct platform_driver da9062_wdt_driver = {
+ .probe = da9062_wdt_probe,
+ .remove = da9062_wdt_remove,
+ .driver = {
+ .name = "da9062-watchdog",
+ },
+};
+module_platform_driver(da9062_wdt_driver);
+
+MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
+MODULE_DESCRIPTION("WDT device driver for Dialog DA9062");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform: da9062-watchdog");
--
end-of-patch for PATCH V2