[PATCH 2/2] Add Ricoh RN5T568 PMIC based watchdog

[Sascha Hauer]

On Mon, Jan 17, 2022 at 09:59:08AM +0100, Juergen Borleis wrote:
> ---
>  drivers/watchdog/Kconfig       |   6 ++
>  drivers/watchdog/Makefile      |   1 +
>  drivers/watchdog/rn5t568_wdt.c | 140 +++++++++++++++++++++++++++++++++
>  3 files changed, 147 insertions(+)
>  create mode 100644 drivers/watchdog/rn5t568_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index d605e62..61a096b 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -109,6 +109,12 @@ config STPMIC1_WATCHDOG
>  	help
>  	  Enable to support configuration of the stpmic1's built-in watchdog.
>  
> +config RN568_WATCHDOG
> +	bool "Ricoh RN5t568 PMIC based Watchdog"
> +	depends on MFD_RN568PMIC
> +	help
> +	  Enable to support system control via the PMIC based watchdog.
> +
>  config F71808E_WDT
>  	bool "Fintek F718xx, F818xx Super I/O Watchdog"
>  	depends on X86
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index dbb76a5..84fd2bf 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -16,6 +16,7 @@ obj-$(CONFIG_ARCH_BCM283X) += bcm2835_wdt.o
>  obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o
>  obj-$(CONFIG_STM32_IWDG_WATCHDOG) += stm32_iwdg.o
>  obj-$(CONFIG_STPMIC1_WATCHDOG) += stpmic1_wdt.o
> +obj-$(CONFIG_RN568_WATCHDOG) += rn5t568_wdt.o
>  obj-$(CONFIG_F71808E_WDT) += f71808e_wdt.o
>  obj-$(CONFIG_GPIO_WATCHDOG) += gpio_wdt.o
>  obj-$(CONFIG_ITCO_WDT) += itco_wdt.o
> diff --git a/drivers/watchdog/rn5t568_wdt.c b/drivers/watchdog/rn5t568_wdt.c
> new file mode 100644
> index 0000000..f6e7234
> --- /dev/null
> +++ b/drivers/watchdog/rn5t568_wdt.c
> @@ -0,0 +1,140 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Watchdog driver for Ricoh RN5T618 PMIC
> + *
> + * Copyright (C) 2014 Beniamino Galvani <b.galvani at gmail.com>
> + */
> +
> +#include <common.h>
> +#include <init.h>
> +#include <watchdog.h>
> +#include <regmap.h>
> +#include <of.h>
> +
> +#define RN5T568_WATCHDOG 0x0b
> +# define RN5T568_WATCHDOG_WDPWROFFEN BIT(2)
> +# define RN5T568_WATCHDOG_WDOGTIM_M (BIT(0) | BIT(1))
> +#define RN5T568_PWRIREN 0x12
> +# define RN5T568_PWRIREN_EN_WDOG BIT(6)
> +#define RN5T568_PWRIRQ 0x13
> +# define RN5T568_PWRIRQ_IR_WDOG BIT(6)
> +
> +struct rn5t568_wdt {
> +	struct watchdog wdd;
> +	struct regmap *regmap;
> +	unsigned int timeout;
> +};
> +
> +struct rn5t568_wdt_tim {
> +	u8 reg_val;
> +	u8 time;
> +};
> +
> +static const struct rn5t568_wdt_tim rn5t568_wdt_timeout[] = {
> +	{ .reg_val = 0, .time = 1, },
> +	{ .reg_val = 1, .time = 8, },
> +	{ .reg_val = 2, .time = 32, },
> +	{ .reg_val = 3, .time = 128, },
> +};
> +
> +#define PMIC_WDT_MAX_TIMEOUT 128
> +
> +static int rn5t568_wdt_start(struct regmap *regmap, int idx)
> +{
> +	int ret;
> +
> +	ret = regmap_update_bits(regmap, RN5T568_WATCHDOG, RN5T568_WATCHDOG_WDOGTIM_M,
> +				 rn5t568_wdt_timeout[idx].reg_val);
> +	if (ret)
> +		return ret;
> +
> +	regmap_update_bits(regmap, RN5T568_PWRIRQ, RN5T568_PWRIRQ_IR_WDOG, 0x00);
> +	regmap_update_bits(regmap, RN5T568_PWRIREN, RN5T568_PWRIREN_EN_WDOG, RN5T568_PWRIREN_EN_WDOG);
> +
> +	pr_debug("RN5t: Starting the watchdog with %u seconds\n", rn5t568_wdt_timeout[idx].time);
> +
> +	return regmap_update_bits(regmap, RN5T568_WATCHDOG, RN5T568_WATCHDOG_WDPWROFFEN,
> +				 RN5T568_WATCHDOG_WDPWROFFEN);
> +}
> +
> +static int rn5t568_wdt_stop(struct regmap *regmap)
> +{
> +	int ret;
> +
> +	ret  = regmap_update_bits(regmap, RN5T568_PWRIREN, RN5T568_PWRIREN_EN_WDOG, 0);

You could use regmap_[clear|set]_bits() here and elsewhere in the
driver.


> +	if (ret)
> +		return ret;
> +	return regmap_update_bits(regmap, RN5T568_WATCHDOG, RN5T568_WATCHDOG_WDPWROFFEN, 0);
> +}
> +
> +static int rn5t568_wdt_ping(struct regmap *regmap)
> +{
> +	unsigned int val;
> +	int ret;
> +
> +	ret = regmap_read(regmap, RN5T568_WATCHDOG, &val);
> +	if (ret)
> +		return ret;
> +
> +	return regmap_write(regmap, RN5T568_WATCHDOG, val);
> +}
> +
> +static int rn5t568_wdt_set_timeout(struct watchdog *wdd, unsigned int timeout)
> +{
> +	struct rn5t568_wdt *wdt = container_of(wdd, struct rn5t568_wdt, wdd);
> +	int ret, i;
> +
> +	if (!timeout)
> +		return rn5t568_wdt_stop(wdt->regmap);
> +
> +	for (i = 0; i < ARRAY_SIZE(rn5t568_wdt_timeout); i++) {
> +		if (rn5t568_wdt_timeout[i].time + 1 >= timeout)

I don't understand the + 1 here. When I want to have a timeout of 9s the
driver uses 8s instead which doesn't seem to be correct.

> +			break;
> +	}
> +
> +	if (i == ARRAY_SIZE(rn5t568_wdt_timeout))
> +		return -EINVAL;
> +
> +	if (wdt->timeout == timeout)
> +		return rn5t568_wdt_ping(wdt->regmap);
> +
> +	ret = rn5t568_wdt_start(wdt->regmap, i);
> +	if (ret)
> +		return ret;
> +
> +	wdt->timeout = rn5t568_wdt_timeout[i].time;
> +
> +	return ret;
> +}
> +
> +static int rn5t568_wdt_probe(struct device_d *dev)
> +{
> +	struct rn5t568_wdt *wdt;
> +	struct watchdog *wdd;
> +
> +	wdt = xzalloc(sizeof(*wdt));
> +
> +	wdt->regmap = dev_get_regmap(dev->parent, NULL);
> +	if (IS_ERR(wdt->regmap))
> +		return PTR_ERR(wdt->regmap);
> +
> +	wdd = &wdt->wdd;
> +	wdd->hwdev = dev;
> +	wdd->set_timeout = rn5t568_wdt_set_timeout;
> +	wdd->timeout_max = PMIC_WDT_MAX_TIMEOUT;
> +
> +	regmap_write(wdt->regmap, RN5T568_WATCHDOG, 0x03);

Why is anything written here to the register?

It seems this clears BIT(2) which disables the watchdog, right? If so,
that's not a good idea as it might be disabled on purpose by earlier
boot stages.

You could read the hardware status to provide the
WDOG_HW_RUNNING/WDOG_HW_NOT_RUNNING flag.

Sascha


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