#include <linux/clk.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.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>
#include <dt-bindings/mfd/st-lpc.h>
#define LPC_LPA_LSB_OFF 0x410
#define LPC_LPA_START_OFF 0x418
#define LPC_WDT_OFF 0x510
static struct watchdog_device st_wdog_dev;
struct st_wdog_syscfg {
unsigned int reset_type_reg;
unsigned int reset_type_mask;
unsigned int enable_reg;
unsigned int enable_mask;
};
struct st_wdog {
void __iomem *base;
struct device *dev;
struct regmap *regmap;
const struct st_wdog_syscfg *syscfg;
struct clk *clk;
unsigned long clkrate;
bool warm_reset;
};
static struct st_wdog_syscfg stih407_syscfg = {
.enable_reg = 0x204,
.enable_mask = BIT(19),
};
static const struct of_device_id st_wdog_match[] = {
{
.compatible = "st,stih407-lpc",
.data = &stih407_syscfg,
},
{},
};
MODULE_DEVICE_TABLE(of, st_wdog_match);
static void st_wdog_setup(struct st_wdog *st_wdog, bool enable)
{
if (st_wdog->syscfg->reset_type_reg)
regmap_update_bits(st_wdog->regmap,
st_wdog->syscfg->reset_type_reg,
st_wdog->syscfg->reset_type_mask,
st_wdog->warm_reset);
regmap_update_bits(st_wdog->regmap,
st_wdog->syscfg->enable_reg,
st_wdog->syscfg->enable_mask,
enable ? 0 : st_wdog->syscfg->enable_mask);
}
static void st_wdog_load_timer(struct st_wdog *st_wdog, unsigned int timeout)
{
unsigned long clkrate = st_wdog->clkrate;
writel_relaxed(timeout * clkrate, st_wdog->base + LPC_LPA_LSB_OFF);
writel_relaxed(1, st_wdog->base + LPC_LPA_START_OFF);
}
static int st_wdog_start(struct watchdog_device *wdd)
{
struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
writel_relaxed(1, st_wdog->base + LPC_WDT_OFF);
return 0;
}
static int st_wdog_stop(struct watchdog_device *wdd)
{
struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
writel_relaxed(0, st_wdog->base + LPC_WDT_OFF);
return 0;
}
static int st_wdog_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
wdd->timeout = timeout;
st_wdog_load_timer(st_wdog, timeout);
return 0;
}
static int st_wdog_keepalive(struct watchdog_device *wdd)
{
struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
st_wdog_load_timer(st_wdog, wdd->timeout);
return 0;
}
static const struct watchdog_info st_wdog_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "ST LPC WDT",
};
static const struct watchdog_ops st_wdog_ops = {
.owner = THIS_MODULE,
.start = st_wdog_start,
.stop = st_wdog_stop,
.ping = st_wdog_keepalive,
.set_timeout = st_wdog_set_timeout,
};
static struct watchdog_device st_wdog_dev = {
.info = &st_wdog_info,
.ops = &st_wdog_ops,
};
static void st_clk_disable_unprepare(void *data)
{
clk_disable_unprepare(data);
}
static int st_wdog_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->of_node;
struct st_wdog *st_wdog;
struct regmap *regmap;
struct clk *clk;
void __iomem *base;
uint32_t mode;
int ret;
ret = of_property_read_u32(np, "st,lpc-mode", &mode);
if (ret) {
dev_err(dev, "An LPC mode must be provided\n");
return -EINVAL;
}
if (mode != ST_LPC_MODE_WDT)
return -ENODEV;
st_wdog = devm_kzalloc(dev, sizeof(*st_wdog), GFP_KERNEL);
if (!st_wdog)
return -ENOMEM;
st_wdog->syscfg = (struct st_wdog_syscfg *)device_get_match_data(dev);
base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base))
return PTR_ERR(base);
regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
if (IS_ERR(regmap)) {
dev_err(dev, "No syscfg phandle specified\n");
return PTR_ERR(regmap);
}
clk = devm_clk_get(dev, NULL);
if (IS_ERR(clk)) {
dev_err(dev, "Unable to request clock\n");
return PTR_ERR(clk);
}
st_wdog->dev = dev;
st_wdog->base = base;
st_wdog->clk = clk;
st_wdog->regmap = regmap;
st_wdog->warm_reset = of_property_read_bool(np, "st,warm_reset");
st_wdog->clkrate = clk_get_rate(st_wdog->clk);
if (!st_wdog->clkrate) {
dev_err(dev, "Unable to fetch clock rate\n");
return -EINVAL;
}
st_wdog_dev.max_timeout = 0xFFFFFFFF / st_wdog->clkrate;
st_wdog_dev.parent = dev;
ret = clk_prepare_enable(clk);
if (ret) {
dev_err(dev, "Unable to enable clock\n");
return ret;
}
ret = devm_add_action_or_reset(dev, st_clk_disable_unprepare, clk);
if (ret)
return ret;
watchdog_set_drvdata(&st_wdog_dev, st_wdog);
watchdog_set_nowayout(&st_wdog_dev, WATCHDOG_NOWAYOUT);
ret = watchdog_init_timeout(&st_wdog_dev, 0, dev);
if (ret)
return ret;
ret = devm_watchdog_register_device(dev, &st_wdog_dev);
if (ret)
return ret;
st_wdog_setup(st_wdog, true);
dev_info(dev, "LPC Watchdog driver registered, reset type is %s",
st_wdog->warm_reset ? "warm" : "cold");
return ret;
}
static void st_wdog_remove(struct platform_device *pdev)
{
struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
st_wdog_setup(st_wdog, false);
}
static int st_wdog_suspend(struct device *dev)
{
struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
if (watchdog_active(&st_wdog_dev))
st_wdog_stop(&st_wdog_dev);
st_wdog_setup(st_wdog, false);
clk_disable(st_wdog->clk);
return 0;
}
static int st_wdog_resume(struct device *dev)
{
struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
int ret;
ret = clk_enable(st_wdog->clk);
if (ret) {
dev_err(dev, "Unable to re-enable clock\n");
watchdog_unregister_device(&st_wdog_dev);
clk_unprepare(st_wdog->clk);
return ret;
}
st_wdog_setup(st_wdog, true);
if (watchdog_active(&st_wdog_dev)) {
st_wdog_load_timer(st_wdog, st_wdog_dev.timeout);
st_wdog_start(&st_wdog_dev);
}
return 0;
}
static DEFINE_SIMPLE_DEV_PM_OPS(st_wdog_pm_ops,
st_wdog_suspend, st_wdog_resume);
static struct platform_driver st_wdog_driver = {
.driver = {
.name = "st-lpc-wdt",
.pm = pm_sleep_ptr(&st_wdog_pm_ops),
.of_match_table = st_wdog_match,
},
.probe = st_wdog_probe,
.remove = st_wdog_remove,
};
module_platform_driver(st_wdog_driver);
MODULE_AUTHOR("David Paris <david.paris@st.com>");
MODULE_DESCRIPTION("ST LPC Watchdog Driver");
MODULE_LICENSE("GPL");
