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    SubjectRe: [PATCH v5 8/8] watchdog: stpmic1: add stpmic1 watchdog driver
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    On 10/29/18 9:22 AM, Pascal PAILLET-LME wrote:
    > The stpmic1 PMIC embeds a watchdog which is disabled by default. As soon
    > as the watchdog is started, it must be refreshed periodically otherwise
    > the PMIC goes off.
    >
    > Signed-off-by: Pascal Paillet <p.paillet@st.com>

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

    > ---
    > changes in v5:
    > * initialize wdtdev.parent
    > * fix checkpatch warning
    >
    > drivers/watchdog/Kconfig | 12 ++++
    > drivers/watchdog/Makefile | 1 +
    > drivers/watchdog/stpmic1_wdt.c | 139 +++++++++++++++++++++++++++++++++++++++++
    > 3 files changed, 152 insertions(+)
    > create mode 100644 drivers/watchdog/stpmic1_wdt.c
    >
    > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
    > index 5ea8909..6d2ffef 100644
    > --- a/drivers/watchdog/Kconfig
    > +++ b/drivers/watchdog/Kconfig
    > @@ -806,6 +806,18 @@ config STM32_WATCHDOG
    > To compile this driver as a module, choose M here: the
    > module will be called stm32_iwdg.
    >
    > +config STPMIC1_WATCHDOG
    > + tristate "STPMIC1 PMIC watchdog support"
    > + depends on MFD_STPMIC1
    > + select WATCHDOG_CORE
    > + help
    > + Say Y here to include watchdog support embedded into STPMIC1 PMIC.
    > + If the watchdog timer expires, stpmic1 will shut down all its power
    > + supplies.
    > +
    > + To compile this driver as a module, choose M here: the
    > + module will be called spmic1_wdt.
    > +
    > config UNIPHIER_WATCHDOG
    > tristate "UniPhier watchdog support"
    > depends on ARCH_UNIPHIER || COMPILE_TEST
    > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
    > index bf92e7b..2649cf3 100644
    > --- a/drivers/watchdog/Makefile
    > +++ b/drivers/watchdog/Makefile
    > @@ -217,3 +217,4 @@ obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
    > obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o
    > obj-$(CONFIG_MENZ069_WATCHDOG) += menz69_wdt.o
    > obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o
    > +obj-$(CONFIG_STPMIC1_WATCHDOG) += stpmic1_wdt.o
    > diff --git a/drivers/watchdog/stpmic1_wdt.c b/drivers/watchdog/stpmic1_wdt.c
    > new file mode 100644
    > index 0000000..ad431d8
    > --- /dev/null
    > +++ b/drivers/watchdog/stpmic1_wdt.c
    > @@ -0,0 +1,139 @@
    > +// SPDX-License-Identifier: GPL-2.0
    > +// Copyright (C) STMicroelectronics 2018
    > +// Author: Pascal Paillet <p.paillet@st.com> for STMicroelectronics.
    > +
    > +#include <linux/kernel.h>
    > +#include <linux/mfd/stpmic1.h>
    > +#include <linux/module.h>
    > +#include <linux/platform_device.h>
    > +#include <linux/of.h>
    > +#include <linux/regmap.h>
    > +#include <linux/slab.h>
    > +#include <linux/watchdog.h>
    > +
    > +/* WATCHDOG CONTROL REGISTER bit */
    > +#define WDT_START BIT(0)
    > +#define WDT_PING BIT(1)
    > +#define WDT_START_MASK BIT(0)
    > +#define WDT_PING_MASK BIT(1)
    > +#define WDT_STOP 0
    > +
    > +#define PMIC_WDT_MIN_TIMEOUT 1
    > +#define PMIC_WDT_MAX_TIMEOUT 256
    > +#define PMIC_WDT_DEFAULT_TIMEOUT 30
    > +
    > +static bool nowayout = WATCHDOG_NOWAYOUT;
    > +module_param(nowayout, bool, 0);
    > +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
    > + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
    > +
    > +struct stpmic1_wdt {
    > + struct stpmic1 *pmic;
    > + struct watchdog_device wdtdev;
    > +};
    > +
    > +static int pmic_wdt_start(struct watchdog_device *wdd)
    > +{
    > + struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
    > +
    > + return regmap_update_bits(wdt->pmic->regmap,
    > + WCHDG_CR, WDT_START_MASK, WDT_START);
    > +}
    > +
    > +static int pmic_wdt_stop(struct watchdog_device *wdd)
    > +{
    > + struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
    > +
    > + return regmap_update_bits(wdt->pmic->regmap,
    > + WCHDG_CR, WDT_START_MASK, WDT_STOP);
    > +}
    > +
    > +static int pmic_wdt_ping(struct watchdog_device *wdd)
    > +{
    > + struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
    > +
    > + return regmap_update_bits(wdt->pmic->regmap,
    > + WCHDG_CR, WDT_PING_MASK, WDT_PING);
    > +}
    > +
    > +static int pmic_wdt_set_timeout(struct watchdog_device *wdd,
    > + unsigned int timeout)
    > +{
    > + struct stpmic1_wdt *wdt = watchdog_get_drvdata(wdd);
    > +
    > + wdd->timeout = timeout;
    > + /* timeout is equal to register value + 1 */
    > + return regmap_write(wdt->pmic->regmap, WCHDG_TIMER_CR, timeout - 1);
    > +}
    > +
    > +static const struct watchdog_info pmic_watchdog_info = {
    > + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
    > + .identity = "STPMIC1 PMIC Watchdog",
    > +};
    > +
    > +static const struct watchdog_ops pmic_watchdog_ops = {
    > + .owner = THIS_MODULE,
    > + .start = pmic_wdt_start,
    > + .stop = pmic_wdt_stop,
    > + .ping = pmic_wdt_ping,
    > + .set_timeout = pmic_wdt_set_timeout,
    > +};
    > +
    > +static int pmic_wdt_probe(struct platform_device *pdev)
    > +{
    > + int ret;
    > + struct stpmic1 *pmic;
    > + struct stpmic1_wdt *wdt;
    > +
    > + if (!pdev->dev.parent)
    > + return -EINVAL;
    > +
    > + pmic = dev_get_drvdata(pdev->dev.parent);
    > + if (!pmic)
    > + return -EINVAL;
    > +
    > + wdt = devm_kzalloc(&pdev->dev, sizeof(struct stpmic1_wdt), GFP_KERNEL);
    > + if (!wdt)
    > + return -ENOMEM;
    > +
    > + wdt->pmic = pmic;
    > +
    > + wdt->wdtdev.info = &pmic_watchdog_info;
    > + wdt->wdtdev.ops = &pmic_watchdog_ops;
    > + wdt->wdtdev.min_timeout = PMIC_WDT_MIN_TIMEOUT;
    > + wdt->wdtdev.max_timeout = PMIC_WDT_MAX_TIMEOUT;
    > + wdt->wdtdev.parent = &pdev->dev;
    > +
    > + wdt->wdtdev.timeout = PMIC_WDT_DEFAULT_TIMEOUT;
    > + watchdog_init_timeout(&wdt->wdtdev, 0, &pdev->dev);
    > +
    > + watchdog_set_nowayout(&wdt->wdtdev, nowayout);
    > + watchdog_set_drvdata(&wdt->wdtdev, wdt);
    > +
    > + ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdtdev);
    > + if (ret)
    > + return ret;
    > +
    > + dev_dbg(wdt->pmic->dev, "PMIC Watchdog driver probed\n");
    > + return 0;
    > +}
    > +
    > +static const struct of_device_id of_pmic_wdt_match[] = {
    > + { .compatible = "st,stpmic1-wdt" },
    > + { },
    > +};
    > +
    > +MODULE_DEVICE_TABLE(of, of_pmic_wdt_match);
    > +
    > +static struct platform_driver stpmic1_wdt_driver = {
    > + .probe = pmic_wdt_probe,
    > + .driver = {
    > + .name = "stpmic1-wdt",
    > + .of_match_table = of_pmic_wdt_match,
    > + },
    > +};
    > +module_platform_driver(stpmic1_wdt_driver);
    > +
    > +MODULE_DESCRIPTION("Watchdog driver for STPMIC1 device");
    > +MODULE_AUTHOR("Pascal Paillet <p.paillet@st.com>");
    > +MODULE_LICENSE("GPL v2");
    >

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