watchdog: stpmic1: Add STPMIC1 watchdog driver
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@st.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
diff --git a/drivers/watchdog/stpmic1_wdt.c b/drivers/watchdog/stpmic1_wdt.c
new file mode 100644
index 0000000..ad431d8
--- /dev/null
+++ b/drivers/watchdog/stpmic1_wdt.c
@@ -0,0 +1,139 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) STMicroelectronics 2018
+// Author: Pascal Paillet <p.paillet@st.com> 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/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 WDT_STOP 0
+
+#define PMIC_WDT_MIN_TIMEOUT 1
+#define PMIC_WDT_MAX_TIMEOUT 256
+#define PMIC_WDT_DEFAULT_TIMEOUT 30
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+struct stpmic1_wdt {
+ struct stpmic1 *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_STOP);
+}
+
+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);
+
+ wdd->timeout = timeout;
+ /* timeout is equal to register value + 1 */
+ return regmap_write(wdt->pmic->regmap, WCHDG_TIMER_CR, timeout - 1);
+}
+
+static const struct watchdog_info pmic_watchdog_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | 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 *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.parent = &pdev->dev;
+
+ wdt->wdtdev.timeout = PMIC_WDT_DEFAULT_TIMEOUT;
+ watchdog_init_timeout(&wdt->wdtdev, 0, &pdev->dev);
+
+ watchdog_set_nowayout(&wdt->wdtdev, nowayout);
+ watchdog_set_drvdata(&wdt->wdtdev, wdt);
+
+ 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 <p.paillet@st.com>");
+MODULE_LICENSE("GPL v2");
