--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2018 Nuvoton Technology corporation.
+// Copyright (c) 2018 IBM Corp.
+
+#include <linux/bitops.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;
+};
+
+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 (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);
+
+ 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);
+
+ 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;
+ struct resource *res;
+ int irq;
+ int ret;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ wdt->reg = devm_ioremap_resource(dev, res);
+ if (IS_ERR(wdt->reg))
+ return PTR_ERR(wdt->reg);
+
+ 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) {
+ dev_err(dev, "failed to register watchdog\n");
+ 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,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");
projects / platform / kernel / linux-rpi.git / commitdiff