On 9/17/20 1:03 AM, Matti Vaittinen wrote:
> 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@xxxxxxxxxxxxxxxxx>
> ---
> drivers/watchdog/Kconfig | 13 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/bd9576_wdt.c | 295 ++++++++++++++++++++++++++++++++++
> 3 files changed, 309 insertions(+)
> create mode 100644 drivers/watchdog/bd9576_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index ab7aad5a1e69..d042a517a946 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -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
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 97bed1d3d97c..14d75f98e3df 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -208,6 +208,7 @@ 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
> diff --git a/drivers/watchdog/bd9576_wdt.c b/drivers/watchdog/bd9576_wdt.c
> new file mode 100644
> index 000000000000..917c8c7ddeb1
> --- /dev/null
> +++ b/drivers/watchdog/bd9576_wdt.c
> @@ -0,0 +1,295 @@
> +// 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/delay.h>
Alphabetic include file order please.
> +#include <linux/mfd/rohm-bd957x.h>
> +#include <linux/module.h>
> +#include <linux/gpio/consumer.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
> +
> +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, hw_margin_min;
> + 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)) {
devm_gpiod_get_from_of_node() can return -EPROBE_DEFER in which case we don't want to see
an error message. I would suggest to use dev_err_probe().
> + dev_err(dev, "getting watchdog-enable GPIO failed\n");
> + return PTR_ERR(priv->gpiod_en);
> + }
> +
> + 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)) {
> + dev_err(dev, "getting watchdog-ping GPIO failed\n");
> + return PTR_ERR(priv->gpiod_ping);
> + }
Same as above.
> +
> + ret = of_property_read_u32(np,
> + "hw_margin_ms", &hw_margin);
Line splits are arbitrary. Why is this "hw_margin_ms" and not "rohm,hw_margin_ms" ?
> + if (ret) {
> + if (ret != -EINVAL)
> + return ret;
> +
> + hw_margin = BD957X_WDT_DEFAULT_MARGIN;
> + }
> +
> + ret = of_property_read_u32(np, "rohm,hw-margin-min-ms", &hw_margin_min);
> + if (ret == -EINVAL)
> + hw_margin_min = 0;
> + else if (ret)
> + return ret;
Please use a single mechanism to handle -EINVAL after of_property_read_u32().
> +
> + ret = bd957x_set_wdt_mode(priv, hw_margin, hw_margin_min);
> + if (ret)
> + return ret;
> +
> + priv->always_running = of_property_read_bool(np,
> + "always-running");
Another arbitrary line split.
> +
> + 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;
> + priv->wdd.parent = dev;
> + priv->wdd.timeout = (hw_margin / 2) * 1000;
> +
> + 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@xxxxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("ROHM BD9576/BD9573 Watchdog driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:bd9576-wdt");
>
