diff options
Diffstat (limited to 'drivers/watchdog/msc313e_wdt.c')
| -rw-r--r-- | drivers/watchdog/msc313e_wdt.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/drivers/watchdog/msc313e_wdt.c b/drivers/watchdog/msc313e_wdt.c new file mode 100644 index 000000000..90171431f --- /dev/null +++ b/drivers/watchdog/msc313e_wdt.c @@ -0,0 +1,170 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * MStar WDT driver + * + * Copyright (C) 2019 - 2021 Daniel Palmer + * Copyright (C) 2021 Romain Perier + * + */ + +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> + +#define REG_WDT_CLR 0x0 +#define REG_WDT_MAX_PRD_L 0x10 +#define REG_WDT_MAX_PRD_H 0x14 + +#define MSC313E_WDT_MIN_TIMEOUT 1 +#define MSC313E_WDT_DEFAULT_TIMEOUT 30 + +static unsigned int timeout; + +module_param(timeout, int, 0); +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); + +struct msc313e_wdt_priv { + void __iomem *base; + struct watchdog_device wdev; + struct clk *clk; +}; + +static int msc313e_wdt_start(struct watchdog_device *wdev) +{ + struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev); + u32 timeout; + int err; + + err = clk_prepare_enable(priv->clk); + if (err) + return err; + + timeout = wdev->timeout * clk_get_rate(priv->clk); + writew(timeout & 0xffff, priv->base + REG_WDT_MAX_PRD_L); + writew((timeout >> 16) & 0xffff, priv->base + REG_WDT_MAX_PRD_H); + writew(1, priv->base + REG_WDT_CLR); + return 0; +} + +static int msc313e_wdt_ping(struct watchdog_device *wdev) +{ + struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev); + + writew(1, priv->base + REG_WDT_CLR); + return 0; +} + +static int msc313e_wdt_stop(struct watchdog_device *wdev) +{ + struct msc313e_wdt_priv *priv = watchdog_get_drvdata(wdev); + + writew(0, priv->base + REG_WDT_MAX_PRD_L); + writew(0, priv->base + REG_WDT_MAX_PRD_H); + writew(0, priv->base + REG_WDT_CLR); + clk_disable_unprepare(priv->clk); + return 0; +} + +static int msc313e_wdt_settimeout(struct watchdog_device *wdev, unsigned int new_time) +{ + wdev->timeout = new_time; + + return msc313e_wdt_start(wdev); +} + +static const struct watchdog_info msc313e_wdt_ident = { + .identity = "MSC313e watchdog", + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, +}; + +static const struct watchdog_ops msc313e_wdt_ops = { + .owner = THIS_MODULE, + .start = msc313e_wdt_start, + .stop = msc313e_wdt_stop, + .ping = msc313e_wdt_ping, + .set_timeout = msc313e_wdt_settimeout, +}; + +static const struct of_device_id msc313e_wdt_of_match[] = { + { .compatible = "mstar,msc313e-wdt", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, msc313e_wdt_of_match); + +static int msc313e_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct msc313e_wdt_priv *priv; + + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + priv->clk = devm_clk_get(dev, NULL); + if (IS_ERR(priv->clk)) { + dev_err(dev, "No input clock\n"); + return PTR_ERR(priv->clk); + } + + priv->wdev.info = &msc313e_wdt_ident, + priv->wdev.ops = &msc313e_wdt_ops, + priv->wdev.parent = dev; + priv->wdev.min_timeout = MSC313E_WDT_MIN_TIMEOUT; + priv->wdev.max_timeout = U32_MAX / clk_get_rate(priv->clk); + priv->wdev.timeout = MSC313E_WDT_DEFAULT_TIMEOUT; + + /* If the period is non-zero the WDT is running */ + if (readw(priv->base + REG_WDT_MAX_PRD_L) | (readw(priv->base + REG_WDT_MAX_PRD_H) << 16)) + set_bit(WDOG_HW_RUNNING, &priv->wdev.status); + + watchdog_set_drvdata(&priv->wdev, priv); + + watchdog_init_timeout(&priv->wdev, timeout, dev); + watchdog_stop_on_reboot(&priv->wdev); + watchdog_stop_on_unregister(&priv->wdev); + + return devm_watchdog_register_device(dev, &priv->wdev); +} + +static int __maybe_unused msc313e_wdt_suspend(struct device *dev) +{ + struct msc313e_wdt_priv *priv = dev_get_drvdata(dev); + + if (watchdog_active(&priv->wdev)) + msc313e_wdt_stop(&priv->wdev); + + return 0; +} + +static int __maybe_unused msc313e_wdt_resume(struct device *dev) +{ + struct msc313e_wdt_priv *priv = dev_get_drvdata(dev); + + if (watchdog_active(&priv->wdev)) + msc313e_wdt_start(&priv->wdev); + + return 0; +} + +static SIMPLE_DEV_PM_OPS(msc313e_wdt_pm_ops, msc313e_wdt_suspend, msc313e_wdt_resume); + +static struct platform_driver msc313e_wdt_driver = { + .driver = { + .name = "msc313e-wdt", + .of_match_table = msc313e_wdt_of_match, + .pm = &msc313e_wdt_pm_ops, + }, + .probe = msc313e_wdt_probe, +}; +module_platform_driver(msc313e_wdt_driver); + +MODULE_AUTHOR("Daniel Palmer <daniel@thingy.jp>"); +MODULE_DESCRIPTION("Watchdog driver for MStar MSC313e"); +MODULE_LICENSE("GPL v2"); |