Re: [PATCH v2 3/4] watchdog: add driver for Ricoh RN5T618 watchdog

[Guenter Roeck <linux@roeck-us.net>]

On 08/30/2014 05:50 AM, Beniamino Galvani wrote:
> This adds a driver for the watchdog timer available in Ricoh RN5T618
> PMIC. The device supports a programmable expiration time of 1, 8, 32
> or 128 seconds.
>
> Signed-off-by: Beniamino Galvani <b.galvani@gmail.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
>   drivers/watchdog/Kconfig       |   11 +++
>   drivers/watchdog/Makefile      |    1 +
>   drivers/watchdog/rn5t618_wdt.c |  198 ++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 210 insertions(+)
>   create mode 100644 drivers/watchdog/rn5t618_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index f57312f..9eba6af 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -309,6 +309,17 @@ config ORION_WATCHDOG
>   	  To compile this driver as a module, choose M here: the
>   	  module will be called orion_wdt.
>
> +config RN5T618_WATCHDOG
> +	tristate "Ricoh RN5T618 watchdog"
> +	depends on MFD_RN5T618
> +	select WATCHDOG_CORE
> +	help
> +	  If you say yes here you get support for watchdog on the Ricoh
> +	  RN5T618 PMIC.
> +
> +	  This driver can also be built as a module.  If so, the module
> +	  will be called rn5t618_wdt.
> +
>   config SUNXI_WATCHDOG
>   	tristate "Allwinner SoCs watchdog support"
>   	depends on ARCH_SUNXI
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 468c320..0afa343 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -47,6 +47,7 @@ obj-$(CONFIG_IOP_WATCHDOG) += iop_wdt.o
>   obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o
>   obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o
>   obj-$(CONFIG_SUNXI_WATCHDOG) += sunxi_wdt.o
> +obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
>   obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
>   obj-$(CONFIG_STMP3XXX_RTC_WATCHDOG) += stmp3xxx_rtc_wdt.o
>   obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
> diff --git a/drivers/watchdog/rn5t618_wdt.c b/drivers/watchdog/rn5t618_wdt.c
> new file mode 100644
> index 0000000..b6d62ac
> --- /dev/null
> +++ b/drivers/watchdog/rn5t618_wdt.c
> @@ -0,0 +1,198 @@
> +/*
> + * Watchdog driver for Ricoh RN5T618 PMIC
> + *
> + * Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License
> + * version 2 as published by the Free Software Foundation.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/mfd/rn5t618.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/watchdog.h>
> +
> +#define DRIVER_NAME "rn5t618-wdt"
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +static unsigned int heartbeat;
> +
> +module_param(heartbeat, int, 0);
> +MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds");
> +
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> +		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +struct rn5t618_wdt {
> +	struct watchdog_device wdt_dev;
> +	struct rn5t618 *rn5t618;
> +};
> +
> +/*
> + * This array encodes the values of WDOGTIM field for the supported
> + * watchdog expiration times. If the watchdog is not accessed before
> + * the timer expiration, the PMU generates an interrupt and if the CPU
> + * doesn't clear it within one second the system is restarted.
> + */
> +static const struct {
> +	u8 reg_val;
> +	unsigned int time;
> +} rn5t618_wdt_map[] = {
> +	{ 0, 1 },
> +	{ 1, 8 },
> +	{ 2, 32 },
> +	{ 3, 128 },
> +};
> +
> +static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev,
> +				   unsigned int timeout)
> +{
> +	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> +	int ret, i;
> +
> +	for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) {
> +		if (rn5t618_wdt_map[i].time + 1 >= timeout)
> +			break;
> +	}
> +
> +	if (i == ARRAY_SIZE(rn5t618_wdt_map))
> +		return -EINVAL;
> +
> +	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
> +				 RN5T618_WATCHDOG_WDOGTIM_M,
> +				 rn5t618_wdt_map[i].reg_val);
> +	if (!ret)
> +		wdt_dev->timeout = rn5t618_wdt_map[i].time;
> +
> +	return ret;
> +}
> +
> +static int rn5t618_wdt_start(struct watchdog_device *wdt_dev)
> +{
> +	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> +	int ret;
> +
> +	ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
> +	if (ret)
> +		return ret;
> +
> +	/* enable repower-on */
> +	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT,
> +				 RN5T618_REPCNT_REPWRON,
> +				 RN5T618_REPCNT_REPWRON);
> +	if (ret)
> +		return ret;
> +
> +	/* enable watchdog */
> +	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
> +				 RN5T618_WATCHDOG_WDOGEN,
> +				 RN5T618_WATCHDOG_WDOGEN);
> +	if (ret)
> +		return ret;
> +
> +	/* enable watchdog interrupt */
> +	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN,
> +				  RN5T618_PWRIRQ_IR_WDOG,
> +				  RN5T618_PWRIRQ_IR_WDOG);
> +}
> +
> +static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev)
> +{
> +	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> +
> +	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
> +				  RN5T618_WATCHDOG_WDOGEN, 0);
> +}
> +
> +static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev)
> +{
> +	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> +	unsigned int val;
> +	int ret;
> +
> +	/* The counter is restarted after a R/W access to watchdog register */
> +	ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(wdt->rn5t618->regmap, RN5T618_WATCHDOG, val);
> +	if (ret)
> +		return ret;
> +
> +	/* Clear pending watchdog interrupt */
> +	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIRQ,
> +				  RN5T618_PWRIRQ_IR_WDOG, 0);
> +}
> +
> +static struct watchdog_info rn5t618_wdt_info = {
> +	.options	= WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
> +			  WDIOF_KEEPALIVEPING,
> +	.identity	= DRIVER_NAME,
> +};
> +
> +static struct watchdog_ops rn5t618_wdt_ops = {
> +	.owner          = THIS_MODULE,
> +	.start          = rn5t618_wdt_start,
> +	.stop           = rn5t618_wdt_stop,
> +	.ping           = rn5t618_wdt_ping,
> +	.set_timeout    = rn5t618_wdt_set_timeout,
> +};
> +
> +static int rn5t618_wdt_probe(struct platform_device *pdev)
> +{
> +	struct rn5t618 *rn5t618 = dev_get_drvdata(pdev->dev.parent);
> +	struct rn5t618_wdt *wdt;
> +	int min_timeout, max_timeout;
> +
> +	wdt = devm_kzalloc(&pdev->dev, sizeof(struct rn5t618_wdt), GFP_KERNEL);
> +	if (!wdt)
> +		return -ENOMEM;
> +
> +	min_timeout = rn5t618_wdt_map[0].time;
> +	max_timeout = rn5t618_wdt_map[ARRAY_SIZE(rn5t618_wdt_map) - 1].time;
> +
> +	wdt->rn5t618 = rn5t618;
> +	wdt->wdt_dev.info = &rn5t618_wdt_info;
> +	wdt->wdt_dev.ops = &rn5t618_wdt_ops;
> +	wdt->wdt_dev.min_timeout = min_timeout;
> +	wdt->wdt_dev.max_timeout = max_timeout;
> +	wdt->wdt_dev.timeout = max_timeout;
> +	wdt->wdt_dev.parent = &pdev->dev;
> +
> +	watchdog_set_drvdata(&wdt->wdt_dev, wdt);
> +	watchdog_init_timeout(&wdt->wdt_dev, heartbeat, &pdev->dev);
> +	watchdog_set_nowayout(&wdt->wdt_dev, nowayout);
> +
> +	platform_set_drvdata(pdev, wdt);
> +
> +	return watchdog_register_device(&wdt->wdt_dev);
> +}
> +
> +static int rn5t618_wdt_remove(struct platform_device *pdev)
> +{
> +	struct rn5t618_wdt *wdt = platform_get_drvdata(pdev);
> +
> +	watchdog_unregister_device(&wdt->wdt_dev);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver rn5t618_wdt_driver = {
> +	.probe = rn5t618_wdt_probe,
> +	.remove = rn5t618_wdt_remove,
> +	.driver = {
> +		.name	= DRIVER_NAME,
> +	},
> +};
> +
> +module_platform_driver(rn5t618_wdt_driver);
> +
> +MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
> +MODULE_DESCRIPTION("RN5T618 watchdog driver");
> +MODULE_LICENSE("GPL v2");
>