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This driver only supports watchdog with I2C feeding and delayed response detection. Whether the watchdog toggles PRSTB pin or just causes an interrupt can be configured via device-tree. The BD96801 PMIC HW supports also window watchdog (too early feeding detection) and Q&A mode. These are not supported by this driver. Signed-off-by: Matti Vaittinen --- drivers/watchdog/Kconfig | 13 ++ drivers/watchdog/Makefile | 1 + drivers/watchdog/bd96801_wdt.c | 375 +++++++++++++++++++++++++++++++++ 3 files changed, 389 insertions(+) create mode 100644 drivers/watchdog/bd96801_wdt.c diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 6bee137cfbe0..d97e735e1faa 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -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 diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index 3710c218f05e..31bc94436c81 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -217,6 +217,7 @@ 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 diff --git a/drivers/watchdog/bd96801_wdt.c b/drivers/watchdog/bd96801_wdt.c new file mode 100644 index 000000000000..cb2b526ecc21 --- /dev/null +++ b/drivers/watchdog/bd96801_wdt.c @@ -0,0 +1,375 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2022 ROHM Semiconductors + * + * ROHM BD96801 watchdog driver + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +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 + +/* units in uS */ +#define FASTNG_MIN 3370 +#define BD96801_WDT_DEFAULT_MARGIN 6905120 +/* 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 meaningfull 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 0r 16 times) the SHORT timeout. + */ + +struct wdtbd96801 { + struct device *dev; + struct regmap *regmap; + bool always_running; + 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); + int ret; + + ret = regmap_update_bits(w->regmap, BD96801_REG_WD_CONF, + BD96801_WD_EN_MASK, BD96801_WD_IF_EN); + + return ret; +} + +static int bd96801_wdt_stop(struct watchdog_device *wdt) +{ + struct wdtbd96801 *w = watchdog_get_drvdata(wdt); + + if (!w->always_running) + return regmap_update_bits(w->regmap, BD96801_REG_WD_CONF, + BD96801_WD_EN_MASK, BD96801_WD_DISABLE); + set_bit(WDOG_HW_RUNNING, &wdt->status); + + return 0; +} + +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(int target, int *sel, int *val) +{ + int i; + int window = FASTNG_MIN; + + for (i = 0; i < 8 && window < target; i++) + window <<= 1; + + *val = window; + *sel = i; + + if (i == 8) + return -EINVAL; + + return 0; +} + +static int find_closest_slow_by_fast(int fast_val, int *target, int *slowsel) +{ + int sel; + static const int multipliers[] = {2, 4, 8, 16}; + + 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(int *target, int *slow_sel, int *fast_sel) +{ + static const int multipliers[] = {2, 4, 8, 16}; + int i, j; + int val = 0; + int window = FASTNG_MIN; + + for (i = 0; i < 8; i++) { + for (j = 0; j < ARRAY_SIZE(multipliers); j++) { + 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, int hw_margin, + int hw_margin_min) +{ + int ret, fastng, slowng, type, reg, mask; + struct device *dev = w->dev; + + /* convert to uS */ + hw_margin *= 1000; + hw_margin_min *= 1000; + if (hw_margin_min) { + 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) { + dev_err(dev, "bad WDT window for fast timeout\n"); + return ret; + } + + ret = find_closest_slow_by_fast(min, &hw_margin, &slowng); + if (ret) { + dev_err(dev, "bad WDT window\n"); + return ret; + } + w->wdt.min_hw_heartbeat_ms = min / 1000; + } 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) { + dev_err(dev, "bad WDT window\n"); + return ret; + } + } + + w->wdt.max_hw_heartbeat_ms = hw_margin / 1000; + + fastng <<= ffs(BD96801_WD_TMO_SHORT_MASK) - 1; + + 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_warn(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 = val & BD96801_WD_TMO_SHORT_MASK; + sel >>= ffs(BD96801_WD_TMO_SHORT_MASK) - 1; + 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, 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) { + hw_margin_max = hw_margin[1]; + hw_margin_min = hw_margin[0]; + } + } + + 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 int bd96801_wdt_probe(struct platform_device *pdev) +{ + struct wdtbd96801 *w; + int ret; + 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); + + w->always_running = device_property_read_bool(pdev->dev.parent, + "always-running"); + + 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; + } + + watchdog_init_timeout(&w->wdt, 0, pdev->dev.parent); + watchdog_set_nowayout(&w->wdt, nowayout); + watchdog_stop_on_reboot(&w->wdt); + + if (w->always_running) + bd96801_wdt_start(&w->wdt); + + return devm_watchdog_register_device(&pdev->dev, &w->wdt); +} + +static struct platform_driver bd96801_wdt = { + .driver = { + .name = "bd96801-wdt" + }, + .probe = bd96801_wdt_probe, +}; +module_platform_driver(bd96801_wdt); + +MODULE_AUTHOR("Matti Vaittinen "); +MODULE_DESCRIPTION("BD96801 watchdog driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:bd96801-wdt");