diff options
Diffstat (limited to 'drivers/watchdog/bd9576_wdt.c')
| -rw-r--r-- | drivers/watchdog/bd9576_wdt.c | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/drivers/watchdog/bd9576_wdt.c b/drivers/watchdog/bd9576_wdt.c new file mode 100644 index 000000000..4a20e07fb --- /dev/null +++ b/drivers/watchdog/bd9576_wdt.c @@ -0,0 +1,302 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2020 ROHM Semiconductors + * + * ROHM BD9576MUF and BD9573MUF Watchdog driver + */ + +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/mfd/rohm-bd957x.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/property.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 HW_MARGIN_MIN 2 +#define HW_MARGIN_MAX 4416 +#define BD957X_WDT_DEFAULT_MARGIN 4416 +#define WATCHDOG_TIMEOUT 30 + +struct bd9576_wdt_priv { + struct gpio_desc *gpiod_ping; + struct gpio_desc *gpiod_en; + struct device *dev; + struct regmap *regmap; + bool always_running; + struct watchdog_device wdd; +}; + +static void bd9576_wdt_disable(struct bd9576_wdt_priv *priv) +{ + gpiod_set_value_cansleep(priv->gpiod_en, 0); +} + +static int bd9576_wdt_ping(struct watchdog_device *wdd) +{ + struct bd9576_wdt_priv *priv = watchdog_get_drvdata(wdd); + + /* Pulse */ + gpiod_set_value_cansleep(priv->gpiod_ping, 1); + gpiod_set_value_cansleep(priv->gpiod_ping, 0); + + return 0; +} + +static int bd9576_wdt_start(struct watchdog_device *wdd) +{ + struct bd9576_wdt_priv *priv = watchdog_get_drvdata(wdd); + + gpiod_set_value_cansleep(priv->gpiod_en, 1); + + return bd9576_wdt_ping(wdd); +} + +static int bd9576_wdt_stop(struct watchdog_device *wdd) +{ + struct bd9576_wdt_priv *priv = watchdog_get_drvdata(wdd); + + if (!priv->always_running) + bd9576_wdt_disable(priv); + else + set_bit(WDOG_HW_RUNNING, &wdd->status); + + return 0; +} + +static const struct watchdog_info bd957x_wdt_ident = { + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | + WDIOF_SETTIMEOUT, + .identity = "BD957x Watchdog", +}; + +static const struct watchdog_ops bd957x_wdt_ops = { + .owner = THIS_MODULE, + .start = bd9576_wdt_start, + .stop = bd9576_wdt_stop, + .ping = bd9576_wdt_ping, +}; + +/* Unit is hundreds of uS */ +#define FASTNG_MIN 23 + +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, 3, 7, 15}; + + for (sel = 0; sel < ARRAY_SIZE(multipliers) && + multipliers[sel] * fast_val < target; sel++) + ; + + if (sel == ARRAY_SIZE(multipliers)) + return -EINVAL; + + *slowsel = sel; + + return 0; +} + +static int find_closest_slow(int target, int *slow_sel, int *fast_sel) +{ + static const int multipliers[] = {2, 3, 7, 15}; + 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; + + return 0; +} + +#define BD957X_WDG_TYPE_WINDOW BIT(5) +#define BD957X_WDG_TYPE_SLOW 0 +#define BD957X_WDG_TYPE_MASK BIT(5) +#define BD957X_WDG_NG_RATIO_MASK 0x18 +#define BD957X_WDG_FASTNG_MASK 0x7 + +static int bd957x_set_wdt_mode(struct bd9576_wdt_priv *priv, int hw_margin, + int hw_margin_min) +{ + int ret, fastng, slowng, type, reg, mask; + struct device *dev = priv->dev; + + /* convert to 100uS */ + hw_margin *= 10; + hw_margin_min *= 10; + if (hw_margin_min) { + int min; + + type = BD957X_WDG_TYPE_WINDOW; + 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; + } + + } else { + type = BD957X_WDG_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; + } + } + + slowng <<= ffs(BD957X_WDG_NG_RATIO_MASK) - 1; + reg = type | slowng | fastng; + mask = BD957X_WDG_TYPE_MASK | BD957X_WDG_NG_RATIO_MASK | + BD957X_WDG_FASTNG_MASK; + ret = regmap_update_bits(priv->regmap, BD957X_REG_WDT_CONF, + mask, reg); + + return ret; +} + +static int bd9576_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct bd9576_wdt_priv *priv; + u32 hw_margin[2]; + u32 hw_margin_max = BD957X_WDT_DEFAULT_MARGIN, hw_margin_min = 0; + int count; + int ret; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + platform_set_drvdata(pdev, priv); + + priv->dev = dev; + priv->regmap = dev_get_regmap(dev->parent, NULL); + if (!priv->regmap) { + dev_err(dev, "No regmap found\n"); + return -ENODEV; + } + + priv->gpiod_en = devm_fwnode_gpiod_get(dev, dev_fwnode(dev->parent), + "rohm,watchdog-enable", + GPIOD_OUT_LOW, + "watchdog-enable"); + if (IS_ERR(priv->gpiod_en)) + return dev_err_probe(dev, PTR_ERR(priv->gpiod_en), + "getting watchdog-enable GPIO failed\n"); + + priv->gpiod_ping = devm_fwnode_gpiod_get(dev, dev_fwnode(dev->parent), + "rohm,watchdog-ping", + GPIOD_OUT_LOW, + "watchdog-ping"); + if (IS_ERR(priv->gpiod_ping)) + return dev_err_probe(dev, PTR_ERR(priv->gpiod_ping), + "getting watchdog-ping GPIO failed\n"); + + count = device_property_count_u32(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(dev->parent, + "rohm,hw-timeout-ms", + hw_margin, 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 = bd957x_set_wdt_mode(priv, hw_margin_max, hw_margin_min); + if (ret) + return ret; + + priv->always_running = device_property_read_bool(dev->parent, + "always-running"); + + watchdog_set_drvdata(&priv->wdd, priv); + + priv->wdd.info = &bd957x_wdt_ident; + priv->wdd.ops = &bd957x_wdt_ops; + priv->wdd.min_hw_heartbeat_ms = hw_margin_min; + priv->wdd.max_hw_heartbeat_ms = hw_margin_max; + priv->wdd.parent = dev; + priv->wdd.timeout = WATCHDOG_TIMEOUT; + + watchdog_init_timeout(&priv->wdd, 0, dev); + watchdog_set_nowayout(&priv->wdd, nowayout); + + watchdog_stop_on_reboot(&priv->wdd); + + if (priv->always_running) + bd9576_wdt_start(&priv->wdd); + + return devm_watchdog_register_device(dev, &priv->wdd); +} + +static struct platform_driver bd9576_wdt_driver = { + .driver = { + .name = "bd9576-wdt", + }, + .probe = bd9576_wdt_probe, +}; + +module_platform_driver(bd9576_wdt_driver); + +MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>"); +MODULE_DESCRIPTION("ROHM BD9576/BD9573 Watchdog driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:bd9576-wdt"); |