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Diffstat (limited to '')
| -rw-r--r-- | drivers/watchdog/npcm_wdt.c | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/drivers/watchdog/npcm_wdt.c b/drivers/watchdog/npcm_wdt.c new file mode 100644 index 000000000..a5dd1c230 --- /dev/null +++ b/drivers/watchdog/npcm_wdt.c @@ -0,0 +1,266 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018 Nuvoton Technology corporation. +// Copyright (c) 2018 IBM Corp. + +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_irq.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/watchdog.h> + +#define NPCM_WTCR 0x1C + +#define NPCM_WTCLK (BIT(10) | BIT(11)) /* Clock divider */ +#define NPCM_WTE BIT(7) /* Enable */ +#define NPCM_WTIE BIT(6) /* Enable irq */ +#define NPCM_WTIS (BIT(4) | BIT(5)) /* Interval selection */ +#define NPCM_WTIF BIT(3) /* Interrupt flag*/ +#define NPCM_WTRF BIT(2) /* Reset flag */ +#define NPCM_WTRE BIT(1) /* Reset enable */ +#define NPCM_WTR BIT(0) /* Reset counter */ + +/* + * Watchdog timeouts + * + * 170 msec: WTCLK=01 WTIS=00 VAL= 0x400 + * 670 msec: WTCLK=01 WTIS=01 VAL= 0x410 + * 1360 msec: WTCLK=10 WTIS=00 VAL= 0x800 + * 2700 msec: WTCLK=01 WTIS=10 VAL= 0x420 + * 5360 msec: WTCLK=10 WTIS=01 VAL= 0x810 + * 10700 msec: WTCLK=01 WTIS=11 VAL= 0x430 + * 21600 msec: WTCLK=10 WTIS=10 VAL= 0x820 + * 43000 msec: WTCLK=11 WTIS=00 VAL= 0xC00 + * 85600 msec: WTCLK=10 WTIS=11 VAL= 0x830 + * 172000 msec: WTCLK=11 WTIS=01 VAL= 0xC10 + * 687000 msec: WTCLK=11 WTIS=10 VAL= 0xC20 + * 2750000 msec: WTCLK=11 WTIS=11 VAL= 0xC30 + */ + +struct npcm_wdt { + struct watchdog_device wdd; + void __iomem *reg; + struct clk *clk; +}; + +static inline struct npcm_wdt *to_npcm_wdt(struct watchdog_device *wdd) +{ + return container_of(wdd, struct npcm_wdt, wdd); +} + +static int npcm_wdt_ping(struct watchdog_device *wdd) +{ + struct npcm_wdt *wdt = to_npcm_wdt(wdd); + u32 val; + + val = readl(wdt->reg); + writel(val | NPCM_WTR, wdt->reg); + + return 0; +} + +static int npcm_wdt_start(struct watchdog_device *wdd) +{ + struct npcm_wdt *wdt = to_npcm_wdt(wdd); + u32 val; + + if (wdt->clk) + clk_prepare_enable(wdt->clk); + + if (wdd->timeout < 2) + val = 0x800; + else if (wdd->timeout < 3) + val = 0x420; + else if (wdd->timeout < 6) + val = 0x810; + else if (wdd->timeout < 11) + val = 0x430; + else if (wdd->timeout < 22) + val = 0x820; + else if (wdd->timeout < 44) + val = 0xC00; + else if (wdd->timeout < 87) + val = 0x830; + else if (wdd->timeout < 173) + val = 0xC10; + else if (wdd->timeout < 688) + val = 0xC20; + else + val = 0xC30; + + val |= NPCM_WTRE | NPCM_WTE | NPCM_WTR | NPCM_WTIE; + + writel(val, wdt->reg); + + return 0; +} + +static int npcm_wdt_stop(struct watchdog_device *wdd) +{ + struct npcm_wdt *wdt = to_npcm_wdt(wdd); + + writel(0, wdt->reg); + + if (wdt->clk) + clk_disable_unprepare(wdt->clk); + + return 0; +} + +static int npcm_wdt_set_timeout(struct watchdog_device *wdd, + unsigned int timeout) +{ + if (timeout < 2) + wdd->timeout = 1; + else if (timeout < 3) + wdd->timeout = 2; + else if (timeout < 6) + wdd->timeout = 5; + else if (timeout < 11) + wdd->timeout = 10; + else if (timeout < 22) + wdd->timeout = 21; + else if (timeout < 44) + wdd->timeout = 43; + else if (timeout < 87) + wdd->timeout = 86; + else if (timeout < 173) + wdd->timeout = 172; + else if (timeout < 688) + wdd->timeout = 687; + else + wdd->timeout = 2750; + + if (watchdog_active(wdd)) + npcm_wdt_start(wdd); + + return 0; +} + +static irqreturn_t npcm_wdt_interrupt(int irq, void *data) +{ + struct npcm_wdt *wdt = data; + + watchdog_notify_pretimeout(&wdt->wdd); + + return IRQ_HANDLED; +} + +static int npcm_wdt_restart(struct watchdog_device *wdd, + unsigned long action, void *data) +{ + struct npcm_wdt *wdt = to_npcm_wdt(wdd); + + /* For reset, we start the WDT clock and leave it running. */ + if (wdt->clk) + clk_prepare_enable(wdt->clk); + + writel(NPCM_WTR | NPCM_WTRE | NPCM_WTE, wdt->reg); + udelay(1000); + + return 0; +} + +static bool npcm_is_running(struct watchdog_device *wdd) +{ + struct npcm_wdt *wdt = to_npcm_wdt(wdd); + + return readl(wdt->reg) & NPCM_WTE; +} + +static const struct watchdog_info npcm_wdt_info = { + .identity = KBUILD_MODNAME, + .options = WDIOF_SETTIMEOUT + | WDIOF_KEEPALIVEPING + | WDIOF_MAGICCLOSE, +}; + +static const struct watchdog_ops npcm_wdt_ops = { + .owner = THIS_MODULE, + .start = npcm_wdt_start, + .stop = npcm_wdt_stop, + .ping = npcm_wdt_ping, + .set_timeout = npcm_wdt_set_timeout, + .restart = npcm_wdt_restart, +}; + +static int npcm_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct npcm_wdt *wdt; + int irq; + int ret; + + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + wdt->reg = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(wdt->reg)) + return PTR_ERR(wdt->reg); + + wdt->clk = devm_clk_get_optional(&pdev->dev, NULL); + if (IS_ERR(wdt->clk)) + return PTR_ERR(wdt->clk); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + wdt->wdd.info = &npcm_wdt_info; + wdt->wdd.ops = &npcm_wdt_ops; + wdt->wdd.min_timeout = 1; + wdt->wdd.max_timeout = 2750; + wdt->wdd.parent = dev; + + wdt->wdd.timeout = 86; + watchdog_init_timeout(&wdt->wdd, 0, dev); + + /* Ensure timeout is able to be represented by the hardware */ + npcm_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout); + + if (npcm_is_running(&wdt->wdd)) { + /* Restart with the default or device-tree specified timeout */ + npcm_wdt_start(&wdt->wdd); + set_bit(WDOG_HW_RUNNING, &wdt->wdd.status); + } + + ret = devm_request_irq(dev, irq, npcm_wdt_interrupt, 0, "watchdog", + wdt); + if (ret) + return ret; + + ret = devm_watchdog_register_device(dev, &wdt->wdd); + if (ret) + return ret; + + dev_info(dev, "NPCM watchdog driver enabled\n"); + + return 0; +} + +#ifdef CONFIG_OF +static const struct of_device_id npcm_wdt_match[] = { + {.compatible = "nuvoton,wpcm450-wdt"}, + {.compatible = "nuvoton,npcm750-wdt"}, + {}, +}; +MODULE_DEVICE_TABLE(of, npcm_wdt_match); +#endif + +static struct platform_driver npcm_wdt_driver = { + .probe = npcm_wdt_probe, + .driver = { + .name = "npcm-wdt", + .of_match_table = of_match_ptr(npcm_wdt_match), + }, +}; +module_platform_driver(npcm_wdt_driver); + +MODULE_AUTHOR("Joel Stanley"); +MODULE_DESCRIPTION("Watchdog driver for NPCM"); +MODULE_LICENSE("GPL v2"); |