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wdt: Support wdt on ROHM BD9576MUF and BD9573MUF

Add Watchdog support for ROHM BD9576MUF and BD9573MUF PMICs which are
mainly used to power the R-Car series processors. The watchdog is
pinged using a GPIO and enabled using another GPIO. Additionally
watchdog time-out can be configured to HW prior starting the watchdog.
Watchdog timeout can be configured to detect only delayed ping or in
a window mode where also too fast pings are detected.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Matti Vaittinen 2021-03-10 10:08:36 +02:00 committed by Lee Jones
parent 0e9692607f
commit b237bcac55
3 changed files with 305 additions and 0 deletions

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@ -172,6 +172,19 @@ config BD70528_WATCHDOG
Alternatively say M to compile the driver as a module,
which will be called bd70528_wdt.
config BD957XMUF_WATCHDOG
tristate "ROHM BD9576MUF and BD9573MUF PMIC Watchdog"
depends on MFD_ROHM_BD957XMUF
select WATCHDOG_CORE
help
Support for the watchdog in the ROHM BD9576 and BD9573 PMICs.
These PMIC ICs contain watchdog block which can be configured
to toggle reset line if SoC fails to ping watchdog via GPIO.
Say Y here to include support for the ROHM BD9576 or BD9573
watchdog. Alternatively say M to compile the driver as a module,
which will be called bd9576_wdt.
config DA9052_WATCHDOG
tristate "Dialog DA9052 Watchdog"
depends on PMIC_DA9052 || COMPILE_TEST

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@ -204,6 +204,7 @@ obj-$(CONFIG_XEN_WDT) += xen_wdt.o
# Architecture Independent
obj-$(CONFIG_BD70528_WATCHDOG) += bd70528_wdt.o
obj-$(CONFIG_BD957XMUF_WATCHDOG) += bd9576_wdt.o
obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o
obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o
obj-$(CONFIG_DA9062_WATCHDOG) += da9062_wdt.o

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@ -0,0 +1,291 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2020 ROHM Semiconductors
*
* ROHM BD9576MUF and BD9573MUF Watchdog driver
*/
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/mfd/rohm-bd957x.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>
static bool nowayout;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default=\"false\")");
#define HW_MARGIN_MIN 2
#define HW_MARGIN_MAX 4416
#define BD957X_WDT_DEFAULT_MARGIN 4416
#define WATCHDOG_TIMEOUT 30
struct bd9576_wdt_priv {
struct gpio_desc *gpiod_ping;
struct gpio_desc *gpiod_en;
struct device *dev;
struct regmap *regmap;
bool always_running;
struct watchdog_device wdd;
};
static void bd9576_wdt_disable(struct bd9576_wdt_priv *priv)
{
gpiod_set_value_cansleep(priv->gpiod_en, 0);
}
static int bd9576_wdt_ping(struct watchdog_device *wdd)
{
struct bd9576_wdt_priv *priv = watchdog_get_drvdata(wdd);
/* Pulse */
gpiod_set_value_cansleep(priv->gpiod_ping, 1);
gpiod_set_value_cansleep(priv->gpiod_ping, 0);
return 0;
}
static int bd9576_wdt_start(struct watchdog_device *wdd)
{
struct bd9576_wdt_priv *priv = watchdog_get_drvdata(wdd);
gpiod_set_value_cansleep(priv->gpiod_en, 1);
return bd9576_wdt_ping(wdd);
}
static int bd9576_wdt_stop(struct watchdog_device *wdd)
{
struct bd9576_wdt_priv *priv = watchdog_get_drvdata(wdd);
if (!priv->always_running)
bd9576_wdt_disable(priv);
else
set_bit(WDOG_HW_RUNNING, &wdd->status);
return 0;
}
static const struct watchdog_info bd957x_wdt_ident = {
.options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
WDIOF_SETTIMEOUT,
.identity = "BD957x Watchdog",
};
static const struct watchdog_ops bd957x_wdt_ops = {
.owner = THIS_MODULE,
.start = bd9576_wdt_start,
.stop = bd9576_wdt_stop,
.ping = bd9576_wdt_ping,
};
/* Unit is hundreds of uS */
#define FASTNG_MIN 23
static int find_closest_fast(int target, int *sel, int *val)
{
int i;
int window = FASTNG_MIN;
for (i = 0; i < 8 && window < target; i++)
window <<= 1;
*val = window;
*sel = i;
if (i == 8)
return -EINVAL;
return 0;
}
static int find_closest_slow_by_fast(int fast_val, int target, int *slowsel)
{
int sel;
static const int multipliers[] = {2, 3, 7, 15};
for (sel = 0; sel < ARRAY_SIZE(multipliers) &&
multipliers[sel] * fast_val < target; sel++)
;
if (sel == ARRAY_SIZE(multipliers))
return -EINVAL;
*slowsel = sel;
return 0;
}
static int find_closest_slow(int target, int *slow_sel, int *fast_sel)
{
static const int multipliers[] = {2, 3, 7, 15};
int i, j;
int val = 0;
int window = FASTNG_MIN;
for (i = 0; i < 8; i++) {
for (j = 0; j < ARRAY_SIZE(multipliers); j++) {
int slow;
slow = window * multipliers[j];
if (slow >= target && (!val || slow < val)) {
val = slow;
*fast_sel = i;
*slow_sel = j;
}
}
window <<= 1;
}
if (!val)
return -EINVAL;
return 0;
}
#define BD957X_WDG_TYPE_WINDOW BIT(5)
#define BD957X_WDG_TYPE_SLOW 0
#define BD957X_WDG_TYPE_MASK BIT(5)
#define BD957X_WDG_NG_RATIO_MASK 0x18
#define BD957X_WDG_FASTNG_MASK 0x7
static int bd957x_set_wdt_mode(struct bd9576_wdt_priv *priv, int hw_margin,
int hw_margin_min)
{
int ret, fastng, slowng, type, reg, mask;
struct device *dev = priv->dev;
/* convert to 100uS */
hw_margin *= 10;
hw_margin_min *= 10;
if (hw_margin_min) {
int min;
type = BD957X_WDG_TYPE_WINDOW;
dev_dbg(dev, "Setting type WINDOW 0x%x\n", type);
ret = find_closest_fast(hw_margin_min, &fastng, &min);
if (ret) {
dev_err(dev, "bad WDT window for fast timeout\n");
return ret;
}
ret = find_closest_slow_by_fast(min, hw_margin, &slowng);
if (ret) {
dev_err(dev, "bad WDT window\n");
return ret;
}
} else {
type = BD957X_WDG_TYPE_SLOW;
dev_dbg(dev, "Setting type SLOW 0x%x\n", type);
ret = find_closest_slow(hw_margin, &slowng, &fastng);
if (ret) {
dev_err(dev, "bad WDT window\n");
return ret;
}
}
slowng <<= ffs(BD957X_WDG_NG_RATIO_MASK) - 1;
reg = type | slowng | fastng;
mask = BD957X_WDG_TYPE_MASK | BD957X_WDG_NG_RATIO_MASK |
BD957X_WDG_FASTNG_MASK;
ret = regmap_update_bits(priv->regmap, BD957X_REG_WDT_CONF,
mask, reg);
return ret;
}
static int bd9576_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *np = dev->parent->of_node;
struct bd9576_wdt_priv *priv;
u32 hw_margin[2];
u32 hw_margin_max = BD957X_WDT_DEFAULT_MARGIN, hw_margin_min = 0;
int ret;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
platform_set_drvdata(pdev, priv);
priv->dev = dev;
priv->regmap = dev_get_regmap(dev->parent, NULL);
if (!priv->regmap) {
dev_err(dev, "No regmap found\n");
return -ENODEV;
}
priv->gpiod_en = devm_gpiod_get_from_of_node(dev, dev->parent->of_node,
"rohm,watchdog-enable-gpios",
0, GPIOD_OUT_LOW,
"watchdog-enable");
if (IS_ERR(priv->gpiod_en))
return dev_err_probe(dev, PTR_ERR(priv->gpiod_en),
"getting watchdog-enable GPIO failed\n");
priv->gpiod_ping = devm_gpiod_get_from_of_node(dev, dev->parent->of_node,
"rohm,watchdog-ping-gpios",
0, GPIOD_OUT_LOW,
"watchdog-ping");
if (IS_ERR(priv->gpiod_ping))
return dev_err_probe(dev, PTR_ERR(priv->gpiod_ping),
"getting watchdog-ping GPIO failed\n");
ret = of_property_read_variable_u32_array(np, "rohm,hw-timeout-ms",
&hw_margin[0], 1, 2);
if (ret < 0 && ret != -EINVAL)
return ret;
if (ret == 1)
hw_margin_max = hw_margin[0];
if (ret == 2) {
hw_margin_max = hw_margin[1];
hw_margin_min = hw_margin[0];
}
ret = bd957x_set_wdt_mode(priv, hw_margin_max, hw_margin_min);
if (ret)
return ret;
priv->always_running = of_property_read_bool(np, "always-running");
watchdog_set_drvdata(&priv->wdd, priv);
priv->wdd.info = &bd957x_wdt_ident;
priv->wdd.ops = &bd957x_wdt_ops;
priv->wdd.min_hw_heartbeat_ms = hw_margin_min;
priv->wdd.max_hw_heartbeat_ms = hw_margin_max;
priv->wdd.parent = dev;
priv->wdd.timeout = WATCHDOG_TIMEOUT;
watchdog_init_timeout(&priv->wdd, 0, dev);
watchdog_set_nowayout(&priv->wdd, nowayout);
watchdog_stop_on_reboot(&priv->wdd);
if (priv->always_running)
bd9576_wdt_start(&priv->wdd);
return devm_watchdog_register_device(dev, &priv->wdd);
}
static struct platform_driver bd9576_wdt_driver = {
.driver = {
.name = "bd9576-wdt",
},
.probe = bd9576_wdt_probe,
};
module_platform_driver(bd9576_wdt_driver);
MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
MODULE_DESCRIPTION("ROHM BD9576/BD9573 Watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:bd9576-wdt");