diff options
Diffstat (limited to 'drivers/watchdog/st_lpc_wdt.c')
| -rw-r--r-- | drivers/watchdog/st_lpc_wdt.c | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/drivers/watchdog/st_lpc_wdt.c b/drivers/watchdog/st_lpc_wdt.c new file mode 100644 index 000000000..14ab6559c --- /dev/null +++ b/drivers/watchdog/st_lpc_wdt.c @@ -0,0 +1,307 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * ST's LPC Watchdog + * + * Copyright (C) 2014 STMicroelectronics -- All Rights Reserved + * + * Author: David Paris <david.paris@st.com> for STMicroelectronics + * Lee Jones <lee.jones@linaro.org> for STMicroelectronics + */ + +#include <linux/clk.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/watchdog.h> + +#include <dt-bindings/mfd/st-lpc.h> + +/* Low Power Alarm */ +#define LPC_LPA_LSB_OFF 0x410 +#define LPC_LPA_START_OFF 0x418 + +/* LPC as WDT */ +#define LPC_WDT_OFF 0x510 + +static struct watchdog_device st_wdog_dev; + +struct st_wdog_syscfg { + unsigned int reset_type_reg; + unsigned int reset_type_mask; + unsigned int enable_reg; + unsigned int enable_mask; +}; + +struct st_wdog { + void __iomem *base; + struct device *dev; + struct regmap *regmap; + struct st_wdog_syscfg *syscfg; + struct clk *clk; + unsigned long clkrate; + bool warm_reset; +}; + +static struct st_wdog_syscfg stih407_syscfg = { + .enable_reg = 0x204, + .enable_mask = BIT(19), +}; + +static const struct of_device_id st_wdog_match[] = { + { + .compatible = "st,stih407-lpc", + .data = &stih407_syscfg, + }, + {}, +}; +MODULE_DEVICE_TABLE(of, st_wdog_match); + +static void st_wdog_setup(struct st_wdog *st_wdog, bool enable) +{ + /* Type of watchdog reset - 0: Cold 1: Warm */ + if (st_wdog->syscfg->reset_type_reg) + regmap_update_bits(st_wdog->regmap, + st_wdog->syscfg->reset_type_reg, + st_wdog->syscfg->reset_type_mask, + st_wdog->warm_reset); + + /* Mask/unmask watchdog reset */ + regmap_update_bits(st_wdog->regmap, + st_wdog->syscfg->enable_reg, + st_wdog->syscfg->enable_mask, + enable ? 0 : st_wdog->syscfg->enable_mask); +} + +static void st_wdog_load_timer(struct st_wdog *st_wdog, unsigned int timeout) +{ + unsigned long clkrate = st_wdog->clkrate; + + writel_relaxed(timeout * clkrate, st_wdog->base + LPC_LPA_LSB_OFF); + writel_relaxed(1, st_wdog->base + LPC_LPA_START_OFF); +} + +static int st_wdog_start(struct watchdog_device *wdd) +{ + struct st_wdog *st_wdog = watchdog_get_drvdata(wdd); + + writel_relaxed(1, st_wdog->base + LPC_WDT_OFF); + + return 0; +} + +static int st_wdog_stop(struct watchdog_device *wdd) +{ + struct st_wdog *st_wdog = watchdog_get_drvdata(wdd); + + writel_relaxed(0, st_wdog->base + LPC_WDT_OFF); + + return 0; +} + +static int st_wdog_set_timeout(struct watchdog_device *wdd, + unsigned int timeout) +{ + struct st_wdog *st_wdog = watchdog_get_drvdata(wdd); + + wdd->timeout = timeout; + st_wdog_load_timer(st_wdog, timeout); + + return 0; +} + +static int st_wdog_keepalive(struct watchdog_device *wdd) +{ + struct st_wdog *st_wdog = watchdog_get_drvdata(wdd); + + st_wdog_load_timer(st_wdog, wdd->timeout); + + return 0; +} + +static const struct watchdog_info st_wdog_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, + .identity = "ST LPC WDT", +}; + +static const struct watchdog_ops st_wdog_ops = { + .owner = THIS_MODULE, + .start = st_wdog_start, + .stop = st_wdog_stop, + .ping = st_wdog_keepalive, + .set_timeout = st_wdog_set_timeout, +}; + +static struct watchdog_device st_wdog_dev = { + .info = &st_wdog_info, + .ops = &st_wdog_ops, +}; + +static void st_clk_disable_unprepare(void *data) +{ + clk_disable_unprepare(data); +} + +static int st_wdog_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + const struct of_device_id *match; + struct device_node *np = dev->of_node; + struct st_wdog *st_wdog; + struct regmap *regmap; + struct clk *clk; + void __iomem *base; + uint32_t mode; + int ret; + + ret = of_property_read_u32(np, "st,lpc-mode", &mode); + if (ret) { + dev_err(dev, "An LPC mode must be provided\n"); + return -EINVAL; + } + + /* LPC can either run as a Clocksource or in RTC or WDT mode */ + if (mode != ST_LPC_MODE_WDT) + return -ENODEV; + + st_wdog = devm_kzalloc(dev, sizeof(*st_wdog), GFP_KERNEL); + if (!st_wdog) + return -ENOMEM; + + match = of_match_device(st_wdog_match, dev); + if (!match) { + dev_err(dev, "Couldn't match device\n"); + return -ENODEV; + } + st_wdog->syscfg = (struct st_wdog_syscfg *)match->data; + + base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(base)) + return PTR_ERR(base); + + regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg"); + if (IS_ERR(regmap)) { + dev_err(dev, "No syscfg phandle specified\n"); + return PTR_ERR(regmap); + } + + clk = devm_clk_get(dev, NULL); + if (IS_ERR(clk)) { + dev_err(dev, "Unable to request clock\n"); + return PTR_ERR(clk); + } + + st_wdog->dev = dev; + st_wdog->base = base; + st_wdog->clk = clk; + st_wdog->regmap = regmap; + st_wdog->warm_reset = of_property_read_bool(np, "st,warm_reset"); + st_wdog->clkrate = clk_get_rate(st_wdog->clk); + + if (!st_wdog->clkrate) { + dev_err(dev, "Unable to fetch clock rate\n"); + return -EINVAL; + } + st_wdog_dev.max_timeout = 0xFFFFFFFF / st_wdog->clkrate; + st_wdog_dev.parent = dev; + + ret = clk_prepare_enable(clk); + if (ret) { + dev_err(dev, "Unable to enable clock\n"); + return ret; + } + ret = devm_add_action_or_reset(dev, st_clk_disable_unprepare, clk); + if (ret) + return ret; + + watchdog_set_drvdata(&st_wdog_dev, st_wdog); + watchdog_set_nowayout(&st_wdog_dev, WATCHDOG_NOWAYOUT); + + /* Init Watchdog timeout with value in DT */ + ret = watchdog_init_timeout(&st_wdog_dev, 0, dev); + if (ret) + return ret; + + ret = devm_watchdog_register_device(dev, &st_wdog_dev); + if (ret) + return ret; + + st_wdog_setup(st_wdog, true); + + dev_info(dev, "LPC Watchdog driver registered, reset type is %s", + st_wdog->warm_reset ? "warm" : "cold"); + + return ret; +} + +static int st_wdog_remove(struct platform_device *pdev) +{ + struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev); + + st_wdog_setup(st_wdog, false); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int st_wdog_suspend(struct device *dev) +{ + struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev); + + if (watchdog_active(&st_wdog_dev)) + st_wdog_stop(&st_wdog_dev); + + st_wdog_setup(st_wdog, false); + + clk_disable(st_wdog->clk); + + return 0; +} + +static int st_wdog_resume(struct device *dev) +{ + struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev); + int ret; + + ret = clk_enable(st_wdog->clk); + if (ret) { + dev_err(dev, "Unable to re-enable clock\n"); + watchdog_unregister_device(&st_wdog_dev); + clk_unprepare(st_wdog->clk); + return ret; + } + + st_wdog_setup(st_wdog, true); + + if (watchdog_active(&st_wdog_dev)) { + st_wdog_load_timer(st_wdog, st_wdog_dev.timeout); + st_wdog_start(&st_wdog_dev); + } + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(st_wdog_pm_ops, + st_wdog_suspend, + st_wdog_resume); + +static struct platform_driver st_wdog_driver = { + .driver = { + .name = "st-lpc-wdt", + .pm = &st_wdog_pm_ops, + .of_match_table = st_wdog_match, + }, + .probe = st_wdog_probe, + .remove = st_wdog_remove, +}; +module_platform_driver(st_wdog_driver); + +MODULE_AUTHOR("David Paris <david.paris@st.com>"); +MODULE_DESCRIPTION("ST LPC Watchdog Driver"); +MODULE_LICENSE("GPL"); |