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kernel-ark/drivers/watchdog/zx2967_wdt.c
Philipp Zabel 39055bbb44 watchdog: zx2967: explicitly request exclusive reset control 
Commit a53e35db70 ("reset: Ensure drivers are explicit when requesting
reset lines") started to transition the reset control request API calls
to explicitly state whether the driver needs exclusive or shared reset
control behavior. Convert all drivers requesting exclusive resets to the
explicit API call so the temporary transition helpers can be removed.

No functional changes.

Cc: linux-watchdog@vger.kernel.org
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
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>
2017-09-09 20:18:43 +02:00

290 lines
7.0 KiB
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/*
* watchdog driver for ZTE's zx2967 family
*
* Copyright (C) 2017 ZTE Ltd.
*
* Author: Baoyou Xie <baoyou.xie@linaro.org>
*
* License terms: GNU General Public License (GPL) version 2
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <linux/watchdog.h>
#define ZX2967_WDT_CFG_REG 0x4
#define ZX2967_WDT_LOAD_REG 0x8
#define ZX2967_WDT_REFRESH_REG 0x18
#define ZX2967_WDT_START_REG 0x1c
#define ZX2967_WDT_REFRESH_MASK GENMASK(5, 0)
#define ZX2967_WDT_CFG_DIV(n) ((((n) & 0xff) - 1) << 8)
#define ZX2967_WDT_START_EN 0x1
/*
* Hardware magic number.
* When watchdog reg is written, the lowest 16 bits are valid, but
* the highest 16 bits should be always this number.
*/
#define ZX2967_WDT_WRITEKEY (0x1234 << 16)
#define ZX2967_WDT_VAL_MASK GENMASK(15, 0)
#define ZX2967_WDT_DIV_DEFAULT 16
#define ZX2967_WDT_DEFAULT_TIMEOUT 32
#define ZX2967_WDT_MIN_TIMEOUT 1
#define ZX2967_WDT_MAX_TIMEOUT 524
#define ZX2967_WDT_MAX_COUNT 0xffff
#define ZX2967_WDT_CLK_FREQ 0x8000
#define ZX2967_WDT_FLAG_REBOOT_MON BIT(0)
struct zx2967_wdt {
struct watchdog_device wdt_device;
void __iomem *reg_base;
struct clk *clock;
};
static inline u32 zx2967_wdt_readl(struct zx2967_wdt *wdt, u16 reg)
{
return readl_relaxed(wdt->reg_base + reg);
}
static inline void zx2967_wdt_writel(struct zx2967_wdt *wdt, u16 reg, u32 val)
{
writel_relaxed(val | ZX2967_WDT_WRITEKEY, wdt->reg_base + reg);
}
static void zx2967_wdt_refresh(struct zx2967_wdt *wdt)
{
u32 val;
val = zx2967_wdt_readl(wdt, ZX2967_WDT_REFRESH_REG);
/*
* Bit 4-5, 1 and 2: refresh config info
* Bit 2-3, 1 and 2: refresh counter
* Bit 0-1, 1 and 2: refresh int-value
* we shift each group value between 1 and 2 to refresh all data.
*/
val ^= ZX2967_WDT_REFRESH_MASK;
zx2967_wdt_writel(wdt, ZX2967_WDT_REFRESH_REG,
val & ZX2967_WDT_VAL_MASK);
}
static int
zx2967_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout)
{
struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
unsigned int divisor = ZX2967_WDT_DIV_DEFAULT;
u32 count;
count = timeout * ZX2967_WDT_CLK_FREQ;
if (count > divisor * ZX2967_WDT_MAX_COUNT)
divisor = DIV_ROUND_UP(count, ZX2967_WDT_MAX_COUNT);
count = DIV_ROUND_UP(count, divisor);
zx2967_wdt_writel(wdt, ZX2967_WDT_CFG_REG,
ZX2967_WDT_CFG_DIV(divisor) & ZX2967_WDT_VAL_MASK);
zx2967_wdt_writel(wdt, ZX2967_WDT_LOAD_REG,
count & ZX2967_WDT_VAL_MASK);
zx2967_wdt_refresh(wdt);
wdd->timeout = (count * divisor) / ZX2967_WDT_CLK_FREQ;
return 0;
}
static void __zx2967_wdt_start(struct zx2967_wdt *wdt)
{
u32 val;
val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG);
val |= ZX2967_WDT_START_EN;
zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG,
val & ZX2967_WDT_VAL_MASK);
}
static void __zx2967_wdt_stop(struct zx2967_wdt *wdt)
{
u32 val;
val = zx2967_wdt_readl(wdt, ZX2967_WDT_START_REG);
val &= ~ZX2967_WDT_START_EN;
zx2967_wdt_writel(wdt, ZX2967_WDT_START_REG,
val & ZX2967_WDT_VAL_MASK);
}
static int zx2967_wdt_start(struct watchdog_device *wdd)
{
struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
zx2967_wdt_set_timeout(wdd, wdd->timeout);
__zx2967_wdt_start(wdt);
return 0;
}
static int zx2967_wdt_stop(struct watchdog_device *wdd)
{
struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
__zx2967_wdt_stop(wdt);
return 0;
}
static int zx2967_wdt_keepalive(struct watchdog_device *wdd)
{
struct zx2967_wdt *wdt = watchdog_get_drvdata(wdd);
zx2967_wdt_refresh(wdt);
return 0;
}
#define ZX2967_WDT_OPTIONS \
(WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
static const struct watchdog_info zx2967_wdt_ident = {
.options = ZX2967_WDT_OPTIONS,
.identity = "zx2967 watchdog",
};
static const struct watchdog_ops zx2967_wdt_ops = {
.owner = THIS_MODULE,
.start = zx2967_wdt_start,
.stop = zx2967_wdt_stop,
.ping = zx2967_wdt_keepalive,
.set_timeout = zx2967_wdt_set_timeout,
};
static void zx2967_wdt_reset_sysctrl(struct device *dev)
{
int ret;
void __iomem *regmap;
unsigned int offset, mask, config;
struct of_phandle_args out_args;
ret = of_parse_phandle_with_fixed_args(dev->of_node,
"zte,wdt-reset-sysctrl", 3, 0, &out_args);
if (ret)
return;
offset = out_args.args[0];
config = out_args.args[1];
mask = out_args.args[2];
regmap = syscon_node_to_regmap(out_args.np);
if (IS_ERR(regmap)) {
of_node_put(out_args.np);
return;
}
regmap_update_bits(regmap, offset, mask, config);
of_node_put(out_args.np);
}
static int zx2967_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct zx2967_wdt *wdt;
struct resource *base;
int ret;
struct reset_control *rstc;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
platform_set_drvdata(pdev, wdt);
wdt->wdt_device.info = &zx2967_wdt_ident;
wdt->wdt_device.ops = &zx2967_wdt_ops;
wdt->wdt_device.timeout = ZX2967_WDT_DEFAULT_TIMEOUT;
wdt->wdt_device.max_timeout = ZX2967_WDT_MAX_TIMEOUT;
wdt->wdt_device.min_timeout = ZX2967_WDT_MIN_TIMEOUT;
wdt->wdt_device.parent = &pdev->dev;
base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
wdt->reg_base = devm_ioremap_resource(dev, base);
if (IS_ERR(wdt->reg_base))
return PTR_ERR(wdt->reg_base);
zx2967_wdt_reset_sysctrl(dev);
wdt->clock = devm_clk_get(dev, NULL);
if (IS_ERR(wdt->clock)) {
dev_err(dev, "failed to find watchdog clock source\n");
return PTR_ERR(wdt->clock);
}
ret = clk_prepare_enable(wdt->clock);
if (ret < 0) {
dev_err(dev, "failed to enable clock\n");
return ret;
}
clk_set_rate(wdt->clock, ZX2967_WDT_CLK_FREQ);
rstc = devm_reset_control_get_exclusive(dev, NULL);
if (IS_ERR(rstc)) {
dev_err(dev, "failed to get rstc");
ret = PTR_ERR(rstc);
goto err;
}
reset_control_assert(rstc);
reset_control_deassert(rstc);
watchdog_set_drvdata(&wdt->wdt_device, wdt);
watchdog_init_timeout(&wdt->wdt_device,
ZX2967_WDT_DEFAULT_TIMEOUT, dev);
watchdog_set_nowayout(&wdt->wdt_device, WATCHDOG_NOWAYOUT);
ret = watchdog_register_device(&wdt->wdt_device);
if (ret)
goto err;
dev_info(dev, "watchdog enabled (timeout=%d sec, nowayout=%d)",
wdt->wdt_device.timeout, WATCHDOG_NOWAYOUT);
return 0;
err:
clk_disable_unprepare(wdt->clock);
return ret;
}
static int zx2967_wdt_remove(struct platform_device *pdev)
{
struct zx2967_wdt *wdt = platform_get_drvdata(pdev);
watchdog_unregister_device(&wdt->wdt_device);
clk_disable_unprepare(wdt->clock);
return 0;
}
static const struct of_device_id zx2967_wdt_match[] = {
{ .compatible = "zte,zx296718-wdt", },
{}
};
MODULE_DEVICE_TABLE(of, zx2967_wdt_match);
static struct platform_driver zx2967_wdt_driver = {
.probe = zx2967_wdt_probe,
.remove = zx2967_wdt_remove,
.driver = {
.name = "zx2967-wdt",
.of_match_table = of_match_ptr(zx2967_wdt_match),
},
};
module_platform_driver(zx2967_wdt_driver);
MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
MODULE_DESCRIPTION("ZTE zx2967 Watchdog Device Driver");
MODULE_LICENSE("GPL v2");
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