diff options
Diffstat (limited to 'drivers/watchdog/menz69_wdt.c')
| -rw-r--r-- | drivers/watchdog/menz69_wdt.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/drivers/watchdog/menz69_wdt.c b/drivers/watchdog/menz69_wdt.c new file mode 100644 index 000000000..ed18238c5 --- /dev/null +++ b/drivers/watchdog/menz69_wdt.c @@ -0,0 +1,170 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Watchdog driver for the MEN z069 IP-Core + * + * Copyright (C) 2018 Johannes Thumshirn <jth@kernel.org> + */ +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/mcb.h> +#include <linux/module.h> +#include <linux/watchdog.h> + +struct men_z069_drv { + struct watchdog_device wdt; + void __iomem *base; + struct resource *mem; +}; + +#define MEN_Z069_WTR 0x10 +#define MEN_Z069_WTR_WDEN BIT(15) +#define MEN_Z069_WTR_WDET_MASK 0x7fff +#define MEN_Z069_WVR 0x14 + +#define MEN_Z069_TIMER_FREQ 500 /* 500 Hz */ +#define MEN_Z069_WDT_COUNTER_MIN 1 +#define MEN_Z069_WDT_COUNTER_MAX 0x7fff +#define MEN_Z069_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) ")"); + +static int men_z069_wdt_start(struct watchdog_device *wdt) +{ + struct men_z069_drv *drv = watchdog_get_drvdata(wdt); + u16 val; + + val = readw(drv->base + MEN_Z069_WTR); + val |= MEN_Z069_WTR_WDEN; + writew(val, drv->base + MEN_Z069_WTR); + + return 0; +} + +static int men_z069_wdt_stop(struct watchdog_device *wdt) +{ + struct men_z069_drv *drv = watchdog_get_drvdata(wdt); + u16 val; + + val = readw(drv->base + MEN_Z069_WTR); + val &= ~MEN_Z069_WTR_WDEN; + writew(val, drv->base + MEN_Z069_WTR); + + return 0; +} + +static int men_z069_wdt_ping(struct watchdog_device *wdt) +{ + struct men_z069_drv *drv = watchdog_get_drvdata(wdt); + u16 val; + + /* The watchdog trigger value toggles between 0x5555 and 0xaaaa */ + val = readw(drv->base + MEN_Z069_WVR); + val ^= 0xffff; + writew(val, drv->base + MEN_Z069_WVR); + + return 0; +} + +static int men_z069_wdt_set_timeout(struct watchdog_device *wdt, + unsigned int timeout) +{ + struct men_z069_drv *drv = watchdog_get_drvdata(wdt); + u16 reg, val, ena; + + wdt->timeout = timeout; + val = timeout * MEN_Z069_TIMER_FREQ; + + reg = readw(drv->base + MEN_Z069_WVR); + ena = reg & MEN_Z069_WTR_WDEN; + reg = ena | val; + writew(reg, drv->base + MEN_Z069_WTR); + + return 0; +} + +static const struct watchdog_info men_z069_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, + .identity = "MEN z069 Watchdog", +}; + +static const struct watchdog_ops men_z069_ops = { + .owner = THIS_MODULE, + .start = men_z069_wdt_start, + .stop = men_z069_wdt_stop, + .ping = men_z069_wdt_ping, + .set_timeout = men_z069_wdt_set_timeout, +}; + +static struct watchdog_device men_z069_wdt = { + .info = &men_z069_info, + .ops = &men_z069_ops, + .timeout = MEN_Z069_DEFAULT_TIMEOUT, + .min_timeout = 1, + .max_timeout = MEN_Z069_WDT_COUNTER_MAX / MEN_Z069_TIMER_FREQ, +}; + +static int men_z069_probe(struct mcb_device *dev, + const struct mcb_device_id *id) +{ + struct men_z069_drv *drv; + struct resource *mem; + + drv = devm_kzalloc(&dev->dev, sizeof(struct men_z069_drv), GFP_KERNEL); + if (!drv) + return -ENOMEM; + + mem = mcb_request_mem(dev, "z069-wdt"); + if (IS_ERR(mem)) + return PTR_ERR(mem); + + drv->base = devm_ioremap(&dev->dev, mem->start, resource_size(mem)); + if (drv->base == NULL) + goto release_mem; + + drv->mem = mem; + + drv->wdt = men_z069_wdt; + watchdog_init_timeout(&drv->wdt, 0, &dev->dev); + watchdog_set_nowayout(&drv->wdt, nowayout); + watchdog_set_drvdata(&drv->wdt, drv); + drv->wdt.parent = &dev->dev; + mcb_set_drvdata(dev, drv); + + return watchdog_register_device(&men_z069_wdt); + +release_mem: + mcb_release_mem(mem); + return -ENOMEM; +} + +static void men_z069_remove(struct mcb_device *dev) +{ + struct men_z069_drv *drv = mcb_get_drvdata(dev); + + watchdog_unregister_device(&drv->wdt); + mcb_release_mem(drv->mem); +} + +static const struct mcb_device_id men_z069_ids[] = { + { .device = 0x45 }, + { } +}; +MODULE_DEVICE_TABLE(mcb, men_z069_ids); + +static struct mcb_driver men_z069_driver = { + .driver = { + .name = "z069-wdt", + .owner = THIS_MODULE, + }, + .probe = men_z069_probe, + .remove = men_z069_remove, + .id_table = men_z069_ids, +}; +module_mcb_driver(men_z069_driver); + +MODULE_AUTHOR("Johannes Thumshirn <jth@kernel.org>"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("mcb:16z069"); |