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watchdog: uniphier: add UniPhier watchdog driver
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Add a watchdog driver for Socionext UniPhier series SoC.
Note that the timeout value for this device must be a power
of 2 because of the specification.

Signed-off-by: Keiji Hayashibara <hayashibara.keiji@socionext.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
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KHayashibara authored and Wim Van Sebroeck committed Jul 3, 2017
1 parent e75bf0e commit e7bf028
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6 changes: 6 additions & 0 deletions Documentation/watchdog/watchdog-parameters.txt
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Expand Up @@ -369,6 +369,12 @@ timeout: Watchdog timeout in seconds. (0<timeout<N, default=60)
nowayout: Watchdog cannot be stopped once started
(default=kernel config parameter)
-------------------------------------------------
uniphier_wdt:
timeout: Watchdog timeout in power of two seconds.
(1 <= timeout <= 128, default=64)
nowayout: Watchdog cannot be stopped once started
(default=kernel config parameter)
-------------------------------------------------
w83627hf_wdt:
wdt_io: w83627hf/thf WDT io port (default 0x2E)
timeout: Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.
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12 changes: 12 additions & 0 deletions drivers/watchdog/Kconfig
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Expand Up @@ -775,6 +775,18 @@ config STM32_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called stm32_iwdg.

config UNIPHIER_WATCHDOG
tristate "UniPhier watchdog support"
depends on ARCH_UNIPHIER || COMPILE_TEST
depends on OF && MFD_SYSCON
select WATCHDOG_CORE
help
Say Y here to include support watchdog timer embedded
into the UniPhier system.

To compile this driver as a module, choose M here: the
module will be called uniphier_wdt.

# AVR32 Architecture

config AT32AP700X_WDT
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1 change: 1 addition & 0 deletions drivers/watchdog/Makefile
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Expand Up @@ -86,6 +86,7 @@ obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o
obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
obj-$(CONFIG_ZX2967_WATCHDOG) += zx2967_wdt.o
obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o

# AVR32 Architecture
obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
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268 changes: 268 additions & 0 deletions drivers/watchdog/uniphier_wdt.c
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@@ -0,0 +1,268 @@
/*
* Watchdog driver for the UniPhier watchdog timer
*
* (c) Copyright 2014 Panasonic Corporation
* (c) Copyright 2016 Socionext Inc.
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/

#include <linux/bitops.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>

/* WDT timer setting register */
#define WDTTIMSET 0x3004
#define WDTTIMSET_PERIOD_MASK (0xf << 0)
#define WDTTIMSET_PERIOD_1_SEC (0x3 << 0)

/* WDT reset selection register */
#define WDTRSTSEL 0x3008
#define WDTRSTSEL_RSTSEL_MASK (0x3 << 0)
#define WDTRSTSEL_RSTSEL_BOTH (0x0 << 0)
#define WDTRSTSEL_RSTSEL_IRQ_ONLY (0x2 << 0)

/* WDT control register */
#define WDTCTRL 0x300c
#define WDTCTRL_STATUS BIT(8)
#define WDTCTRL_CLEAR BIT(1)
#define WDTCTRL_ENABLE BIT(0)

#define SEC_TO_WDTTIMSET_PRD(sec) \
(ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)

#define WDTST_TIMEOUT 1000 /* usec */

#define WDT_DEFAULT_TIMEOUT 64 /* Default is 64 seconds */
#define WDT_PERIOD_MIN 1
#define WDT_PERIOD_MAX 128

static unsigned int timeout = 0;
static bool nowayout = WATCHDOG_NOWAYOUT;

struct uniphier_wdt_dev {
struct watchdog_device wdt_dev;
struct regmap *regmap;
};

/*
* UniPhier Watchdog operations
*/
static int uniphier_watchdog_ping(struct watchdog_device *w)
{
struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
unsigned int val;
int ret;

/* Clear counter */
ret = regmap_write_bits(wdev->regmap, WDTCTRL,
WDTCTRL_CLEAR, WDTCTRL_CLEAR);
if (!ret)
/*
* As SoC specification, after clear counter,
* it needs to wait until counter status is 1.
*/
ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
(val & WDTCTRL_STATUS),
0, WDTST_TIMEOUT);

return ret;
}

static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
{
unsigned int val;
int ret;

ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
!(val & WDTCTRL_STATUS),
0, WDTST_TIMEOUT);
if (ret)
return ret;

/* Setup period */
ret = regmap_write(regmap, WDTTIMSET,
SEC_TO_WDTTIMSET_PRD(sec));
if (ret)
return ret;

/* Enable and clear watchdog */
ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR);
if (!ret)
/*
* As SoC specification, after clear counter,
* it needs to wait until counter status is 1.
*/
ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
(val & WDTCTRL_STATUS),
0, WDTST_TIMEOUT);

return ret;
}

static int __uniphier_watchdog_stop(struct regmap *regmap)
{
/* Disable and stop watchdog */
return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
}

static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
{
int ret;

ret = __uniphier_watchdog_stop(regmap);
if (ret)
return ret;

return __uniphier_watchdog_start(regmap, sec);
}

static int uniphier_watchdog_start(struct watchdog_device *w)
{
struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
unsigned int tmp_timeout;

tmp_timeout = roundup_pow_of_two(w->timeout);

return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
}

static int uniphier_watchdog_stop(struct watchdog_device *w)
{
struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);

return __uniphier_watchdog_stop(wdev->regmap);
}

static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
unsigned int t)
{
struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
unsigned int tmp_timeout;
int ret;

tmp_timeout = roundup_pow_of_two(t);
if (tmp_timeout == w->timeout)
return 0;

if (watchdog_active(w)) {
ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
if (ret)
return ret;
}

w->timeout = tmp_timeout;

return 0;
}

/*
* Kernel Interfaces
*/
static const struct watchdog_info uniphier_wdt_info = {
.identity = "uniphier-wdt",
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE |
WDIOF_OVERHEAT,
};

static const struct watchdog_ops uniphier_wdt_ops = {
.owner = THIS_MODULE,
.start = uniphier_watchdog_start,
.stop = uniphier_watchdog_stop,
.ping = uniphier_watchdog_ping,
.set_timeout = uniphier_watchdog_set_timeout,
};

static int uniphier_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct uniphier_wdt_dev *wdev;
struct regmap *regmap;
struct device_node *parent;
int ret;

wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL);
if (!wdev)
return -ENOMEM;

platform_set_drvdata(pdev, wdev);

parent = of_get_parent(dev->of_node); /* parent should be syscon node */
regmap = syscon_node_to_regmap(parent);
of_node_put(parent);
if (IS_ERR(regmap))
return PTR_ERR(regmap);

wdev->regmap = regmap;
wdev->wdt_dev.info = &uniphier_wdt_info;
wdev->wdt_dev.ops = &uniphier_wdt_ops;
wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
wdev->wdt_dev.parent = dev;

if (watchdog_init_timeout(&wdev->wdt_dev, timeout, dev) < 0) {
wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
}
watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
watchdog_stop_on_reboot(&wdev->wdt_dev);

watchdog_set_drvdata(&wdev->wdt_dev, wdev);

uniphier_watchdog_stop(&wdev->wdt_dev);
ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
if (ret)
return ret;

ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
if (ret)
return ret;

dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
wdev->wdt_dev.timeout, nowayout);

return 0;
}

static const struct of_device_id uniphier_wdt_dt_ids[] = {
{ .compatible = "socionext,uniphier-wdt" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);

static struct platform_driver uniphier_wdt_driver = {
.probe = uniphier_wdt_probe,
.driver = {
.name = "uniphier-wdt",
.of_match_table = uniphier_wdt_dt_ids,
},
};

module_platform_driver(uniphier_wdt_driver);

module_param(timeout, uint, 0000);
MODULE_PARM_DESC(timeout,
"Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");

module_param(nowayout, bool, 0000);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
MODULE_LICENSE("GPL v2");

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