@@ -181,6 +181,19 @@ config BD957XMUF_WATCHDOG
watchdog. Alternatively say M to compile the driver as a module,
which will be called bd9576_wdt.
+config BD96801_WATCHDOG
+ tristate "ROHM BD96801 PMIC Watchdog"
+ depends on MFD_ROHM_BD96801
+ select WATCHDOG_CORE
+ help
+ Support for the watchdog in the ROHM BD96801 PMIC. Watchdog can be
+ configured to only generate IRQ or to trigger system reset via reset
+ pin.
+
+ Say Y here to include support for the ROHM BD96801 watchdog.
+ Alternatively say M to compile the driver as a module,
+ which will be called bd96801_wdt.
+
config CROS_EC_WATCHDOG
tristate "ChromeOS EC-based watchdog"
select WATCHDOG_CORE
@@ -218,6 +218,7 @@ obj-$(CONFIG_XEN_WDT) += xen_wdt.o
# Architecture Independent
obj-$(CONFIG_BD957XMUF_WATCHDOG) += bd9576_wdt.o
+obj-$(CONFIG_BD96801_WATCHDOG) += bd96801_wdt.o
obj-$(CONFIG_CROS_EC_WATCHDOG) += cros_ec_wdt.o
obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o
obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o
new file mode 100644
@@ -0,0 +1,416 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024 ROHM Semiconductors
+ *
+ * ROHM BD96801 watchdog driver
+ */
+
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/rohm-bd96801.h>
+#include <linux/mfd/rohm-generic.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/regmap.h>
+#include <linux/watchdog.h>
+
+static bool nowayout;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+ "Watchdog cannot be stopped once started (default=\"false\")");
+
+#define BD96801_WD_TMO_SHORT_MASK 0x70
+#define BD96801_WD_RATIO_MASK 0x3
+#define BD96801_WD_TYPE_MASK 0x4
+#define BD96801_WD_TYPE_SLOW 0x4
+#define BD96801_WD_TYPE_WIN 0x0
+
+#define BD96801_WD_EN_MASK 0x3
+#define BD96801_WD_IF_EN 0x1
+#define BD96801_WD_QA_EN 0x2
+#define BD96801_WD_DISABLE 0x0
+
+#define BD96801_WD_ASSERT_MASK 0x8
+#define BD96801_WD_ASSERT_RST 0x8
+#define BD96801_WD_ASSERT_IRQ 0x0
+
+#define BD96801_WD_FEED_MASK 0x1
+#define BD96801_WD_FEED 0x1
+
+/* 1.1 mS */
+#define FASTNG_MIN 11
+#define FASTNG_MAX_US (100 * FASTNG_MIN << 7)
+#define SLOWNG_MAX_US (16 * FASTNG_MAX_US)
+
+#define BD96801_WDT_DEFAULT_MARGIN_MS 1843
+/* Unit is seconds */
+#define DEFAULT_TIMEOUT 30
+
+/*
+ * BD96801 WDG supports window mode so the TMO consists of SHORT and LONG
+ * timeout values. SHORT time is meaningful only in window mode where feeding
+ * period shorter than SHORT would be an error. LONG time is used to detect if
+ * feeding is not occurring within given time limit (SoC SW hangs). The LONG
+ * timeout time is a multiple of (2, 4, 8 or 16 times) the SHORT timeout.
+ */
+
+struct wdtbd96801 {
+ struct device *dev;
+ struct regmap *regmap;
+ struct watchdog_device wdt;
+};
+
+static int bd96801_wdt_ping(struct watchdog_device *wdt)
+{
+ struct wdtbd96801 *w = watchdog_get_drvdata(wdt);
+
+ return regmap_update_bits(w->regmap, BD96801_REG_WD_FEED,
+ BD96801_WD_FEED_MASK, BD96801_WD_FEED);
+}
+
+static int bd96801_wdt_start(struct watchdog_device *wdt)
+{
+ struct wdtbd96801 *w = watchdog_get_drvdata(wdt);
+
+ return regmap_update_bits(w->regmap, BD96801_REG_WD_CONF,
+ BD96801_WD_EN_MASK, BD96801_WD_IF_EN);
+}
+
+static int bd96801_wdt_stop(struct watchdog_device *wdt)
+{
+ struct wdtbd96801 *w = watchdog_get_drvdata(wdt);
+
+ return regmap_update_bits(w->regmap, BD96801_REG_WD_CONF,
+ BD96801_WD_EN_MASK, BD96801_WD_DISABLE);
+}
+
+static const struct watchdog_info bd96801_wdt_info = {
+ .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
+ WDIOF_SETTIMEOUT,
+ .identity = "BD96801 Watchdog",
+};
+
+static const struct watchdog_ops bd96801_wdt_ops = {
+ .start = bd96801_wdt_start,
+ .stop = bd96801_wdt_stop,
+ .ping = bd96801_wdt_ping,
+};
+
+static int find_closest_fast(unsigned int target, int *sel, unsigned int *val)
+{
+ unsigned int window = FASTNG_MIN;
+ int i;
+
+ for (i = 0; i < 8 && window < target; i++)
+ window <<= 1;
+
+ if (i == 8)
+ return -EINVAL;
+
+ *val = window;
+ *sel = i;
+
+ return 0;
+}
+
+static int find_closest_slow_by_fast(unsigned int fast_val, unsigned int *target,
+ int *slowsel)
+{
+ static const int multipliers[] = {2, 4, 8, 16};
+ int sel;
+
+ for (sel = 0; sel < ARRAY_SIZE(multipliers) &&
+ multipliers[sel] * fast_val < *target; sel++)
+ ;
+
+ if (sel == ARRAY_SIZE(multipliers))
+ return -EINVAL;
+
+ *slowsel = sel;
+ *target = multipliers[sel] * fast_val;
+
+ return 0;
+}
+
+static int find_closest_slow(unsigned int *target, int *slow_sel, int *fast_sel)
+{
+ static const int multipliers[] = {2, 4, 8, 16};
+ unsigned int window = FASTNG_MIN;
+ unsigned int val = 0;
+ int i, j;
+
+ for (i = 0; i < 8; i++) {
+ for (j = 0; j < ARRAY_SIZE(multipliers); j++) {
+ unsigned int slow;
+
+ slow = window * multipliers[j];
+ if (slow >= *target && (!val || slow < val)) {
+ val = slow;
+ *fast_sel = i;
+ *slow_sel = j;
+ }
+ }
+ window <<= 1;
+ }
+ if (!val)
+ return -EINVAL;
+
+ *target = val;
+
+ return 0;
+}
+
+static int bd96801_set_wdt_mode(struct wdtbd96801 *w, unsigned int hw_margin,
+ unsigned int hw_margin_min)
+{
+ int fastng, slowng, type, ret, reg, mask;
+ struct device *dev = w->dev;
+
+
+ if (hw_margin_min * 1000 > FASTNG_MAX_US) {
+ dev_err(dev, "Unsupported fast timeout %u uS [max %u]\n",
+ hw_margin_min * 1000, FASTNG_MAX_US);
+
+ return -EINVAL;
+ }
+
+ if (hw_margin * 1000 > SLOWNG_MAX_US) {
+ dev_err(dev, "Unsupported slow timeout %u uS [max %u]\n",
+ hw_margin * 1000, SLOWNG_MAX_US);
+
+ return -EINVAL;
+ }
+
+ /*
+ * Convert to 100uS to guarantee reasonable timeouts fit in
+ * 32bit maintaining also a decent accuracy.
+ */
+ hw_margin *= 10;
+ hw_margin_min *= 10;
+
+ if (hw_margin_min) {
+ unsigned int min;
+
+ type = BD96801_WD_TYPE_WIN;
+ dev_dbg(dev, "Setting type WINDOW 0x%x\n", type);
+ ret = find_closest_fast(hw_margin_min, &fastng, &min);
+ if (ret)
+ return ret;
+
+ ret = find_closest_slow_by_fast(min, &hw_margin, &slowng);
+ if (ret) {
+ dev_err(dev,
+ "can't support slow timeout %u uS using fast %u uS. [max slow %u uS]\n",
+ hw_margin * 100, min * 100, min * 100 * 16);
+
+ return ret;
+ }
+ w->wdt.min_hw_heartbeat_ms = min / 10;
+ } else {
+ type = BD96801_WD_TYPE_SLOW;
+ dev_dbg(dev, "Setting type SLOW 0x%x\n", type);
+ ret = find_closest_slow(&hw_margin, &slowng, &fastng);
+ if (ret)
+ return ret;
+ }
+
+ w->wdt.max_hw_heartbeat_ms = hw_margin / 10;
+
+ fastng = FIELD_PREP(BD96801_WD_TMO_SHORT_MASK, fastng);
+
+ reg = slowng | fastng;
+ mask = BD96801_WD_RATIO_MASK | BD96801_WD_TMO_SHORT_MASK;
+ ret = regmap_update_bits(w->regmap, BD96801_REG_WD_TMO,
+ mask, reg);
+ if (ret)
+ return ret;
+
+ ret = regmap_update_bits(w->regmap, BD96801_REG_WD_CONF,
+ BD96801_WD_TYPE_MASK, type);
+
+ return ret;
+}
+
+static int bd96801_set_heartbeat_from_hw(struct wdtbd96801 *w,
+ unsigned int conf_reg)
+{
+ int ret;
+ unsigned int val, sel, fast;
+
+ /*
+ * The BD96801 supports a somewhat peculiar QA-mode, which we do not
+ * support in this driver. If the QA-mode is enabled then we just
+ * warn and bail-out.
+ */
+ if ((conf_reg & BD96801_WD_EN_MASK) != BD96801_WD_IF_EN) {
+ dev_err(w->dev, "watchdog set to Q&A mode - exiting\n");
+ return -EINVAL;
+ }
+
+ ret = regmap_read(w->regmap, BD96801_REG_WD_TMO, &val);
+ if (ret)
+ return ret;
+
+ sel = FIELD_GET(BD96801_WD_TMO_SHORT_MASK, val);
+ fast = FASTNG_MIN << sel;
+
+ sel = (val & BD96801_WD_RATIO_MASK) + 1;
+ w->wdt.max_hw_heartbeat_ms = (fast << sel) / USEC_PER_MSEC;
+
+ if ((conf_reg & BD96801_WD_TYPE_MASK) == BD96801_WD_TYPE_WIN)
+ w->wdt.min_hw_heartbeat_ms = fast / USEC_PER_MSEC;
+
+ return 0;
+}
+
+static int init_wdg_hw(struct wdtbd96801 *w)
+{
+ u32 hw_margin[2];
+ int count, ret;
+ u32 hw_margin_max = BD96801_WDT_DEFAULT_MARGIN_MS, hw_margin_min = 0;
+
+ count = device_property_count_u32(w->dev->parent, "rohm,hw-timeout-ms");
+ if (count < 0 && count != -EINVAL)
+ return count;
+
+ if (count > 0) {
+ if (count > ARRAY_SIZE(hw_margin))
+ return -EINVAL;
+
+ ret = device_property_read_u32_array(w->dev->parent,
+ "rohm,hw-timeout-ms",
+ &hw_margin[0], count);
+ if (ret < 0)
+ return ret;
+
+ if (count == 1)
+ hw_margin_max = hw_margin[0];
+
+ if (count == 2) {
+ if (hw_margin[1] > hw_margin[0]) {
+ hw_margin_max = hw_margin[1];
+ hw_margin_min = hw_margin[0];
+ } else {
+ hw_margin_max = hw_margin[0];
+ hw_margin_min = hw_margin[1];
+ }
+ }
+ }
+
+ ret = bd96801_set_wdt_mode(w, hw_margin_max, hw_margin_min);
+ if (ret)
+ return ret;
+
+ ret = device_property_match_string(w->dev->parent, "rohm,wdg-action",
+ "prstb");
+ if (ret >= 0) {
+ ret = regmap_update_bits(w->regmap, BD96801_REG_WD_CONF,
+ BD96801_WD_ASSERT_MASK,
+ BD96801_WD_ASSERT_RST);
+ return ret;
+ }
+
+ ret = device_property_match_string(w->dev->parent, "rohm,wdg-action",
+ "intb-only");
+ if (ret >= 0) {
+ ret = regmap_update_bits(w->regmap, BD96801_REG_WD_CONF,
+ BD96801_WD_ASSERT_MASK,
+ BD96801_WD_ASSERT_IRQ);
+ return ret;
+ }
+
+ return 0;
+}
+
+static irqreturn_t bd96801_irq_hnd(int irq, void *data)
+{
+ emergency_restart();
+
+ return IRQ_NONE;
+}
+
+static int bd96801_wdt_probe(struct platform_device *pdev)
+{
+ struct wdtbd96801 *w;
+ int ret, irq;
+ unsigned int val;
+
+ w = devm_kzalloc(&pdev->dev, sizeof(*w), GFP_KERNEL);
+ if (!w)
+ return -ENOMEM;
+
+ w->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ w->dev = &pdev->dev;
+
+ w->wdt.info = &bd96801_wdt_info;
+ w->wdt.ops = &bd96801_wdt_ops;
+ w->wdt.parent = pdev->dev.parent;
+ w->wdt.timeout = DEFAULT_TIMEOUT;
+ watchdog_set_drvdata(&w->wdt, w);
+
+ ret = regmap_read(w->regmap, BD96801_REG_WD_CONF, &val);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "Failed to get the watchdog state\n");
+
+ /*
+ * If the WDG is already enabled we assume it is configured by boot.
+ * In this case we just update the hw-timeout based on values set to
+ * the timeout / mode registers and leave the hardware configs
+ * untouched.
+ */
+ if ((val & BD96801_WD_EN_MASK) != BD96801_WD_DISABLE) {
+ dev_dbg(&pdev->dev, "watchdog was running during probe\n");
+ ret = bd96801_set_heartbeat_from_hw(w, val);
+ if (ret)
+ return ret;
+
+ set_bit(WDOG_HW_RUNNING, &w->wdt.status);
+ } else {
+ /* If WDG is not running so we will initializate it */
+ ret = init_wdg_hw(w);
+ if (ret)
+ return ret;
+ }
+
+ dev_dbg(w->dev, "heartbeat set to %u - %u\n",
+ w->wdt.min_hw_heartbeat_ms, w->wdt.max_hw_heartbeat_ms);
+
+ watchdog_init_timeout(&w->wdt, 0, pdev->dev.parent);
+ watchdog_set_nowayout(&w->wdt, nowayout);
+ watchdog_stop_on_reboot(&w->wdt);
+
+ irq = platform_get_irq_byname(pdev, "bd96801-wdg");
+ if (irq > 0) {
+ ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+ bd96801_irq_hnd,
+ IRQF_ONESHOT, "bd96801-wdg",
+ NULL);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "Failed to register IRQ\n");
+ }
+
+ return devm_watchdog_register_device(&pdev->dev, &w->wdt);
+}
+
+static const struct platform_device_id bd96801_wdt_id[] = {
+ { "bd96801-wdt", },
+ { }
+};
+MODULE_DEVICE_TABLE(platform, bd96801_wdt_id);
+
+static struct platform_driver bd96801_wdt = {
+ .driver = {
+ .name = "bd96801-wdt"
+ },
+ .probe = bd96801_wdt_probe,
+ .id_table = bd96801_wdt_id,
+};
+module_platform_driver(bd96801_wdt);
+
+MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
+MODULE_DESCRIPTION("BD96801 watchdog driver");
+MODULE_LICENSE("GPL");