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linux/drivers/watchdog/npcm_wdt.c
Jonathan Neuschäfer af084fdccf watchdog: npcm: Enable clock if provided
On the Nuvoton WPCM450 SoC, with its upcoming clock driver, peripheral
clocks are individually gated and ungated. Therefore, the watchdog
driver must be able to ungate the watchdog clock.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220610072141.347795-3-j.neuschaefer@gmx.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2022-10-02 12:55:41 +02:00

267 lines
5.9 KiB
C

// 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");