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Mon, 11 Oct 2021 10:17:49 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id k3sm1839364otn.16.2021.10.11.10.17.47 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 Oct 2021 10:17:49 -0700 (PDT) Sender: Guenter Roeck Subject: Re: [PATCH 7/8] watchdog: max77714: add driver for the watchdog in the MAX77714 PMIC To: Luca Ceresoli , linux-kernel@vger.kernel.org Cc: Lee Jones , Rob Herring , Alessandro Zummo , Alexandre Belloni , Chanwoo Choi , Krzysztof Kozlowski , Bartlomiej Zolnierkiewicz , Wim Van Sebroeck , devicetree@vger.kernel.org, linux-rtc@vger.kernel.org, linux-watchdog@vger.kernel.org, Chiwoong Byun , Laxman Dewangan References: <20211011155615.257529-1-luca@lucaceresoli.net> <20211011155615.257529-8-luca@lucaceresoli.net> From: Guenter Roeck Message-ID: <8ce6ed51-7963-0279-f771-66226e6b5a6d@roeck-us.net> Date: Mon, 11 Oct 2021 10:17:46 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <20211011155615.257529-8-luca@lucaceresoli.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/11/21 8:56 AM, Luca Ceresoli wrote: > Add a simple driver to suppor the watchdog embedded in the Maxim MAX77714 > PMIC. > > Signed-off-by: Luca Ceresoli > --- > MAINTAINERS | 1 + > drivers/watchdog/Kconfig | 9 ++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/max77714_wdt.c | 171 ++++++++++++++++++++++++++++++++ > 4 files changed, 182 insertions(+) > create mode 100644 drivers/watchdog/max77714_wdt.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index df394192f14e..08900b5729a5 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -11390,6 +11390,7 @@ M: Luca Ceresoli > S: Maintained > F: Documentation/devicetree/bindings/mfd/maxim,max77714.yaml > F: drivers/mfd/max77714.c > +F: drivers/watchdog/max77714_wdt.c > F: include/linux/mfd/max77714.h > > MAXIM MAX77802 PMIC REGULATOR DEVICE DRIVER > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index bf59faeb3de1..00bc3f932a6c 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -699,6 +699,15 @@ config MAX77620_WATCHDOG > MAX77620 chips. To compile this driver as a module, > choose M here: the module will be called max77620_wdt. > > +config MAX77714_WATCHDOG > + tristate "Maxim MAX77714 Watchdog Timer" > + depends on MFD_MAX77714 || COMPILE_TEST > + help > + This is the driver for watchdog timer in the MAX77714 PMIC. > + Say 'Y' here to enable the watchdog timer support for > + MAX77714 chips. To compile this driver as a module, > + choose M here: the module will be called max77714_wdt. > + > config IMX2_WDT > tristate "IMX2+ Watchdog" > depends on ARCH_MXC || ARCH_LAYERSCAPE || COMPILE_TEST > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index 1bd2d6f37c53..268a942311a0 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -215,6 +215,7 @@ obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o > obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o > obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o > obj-$(CONFIG_MAX77620_WATCHDOG) += max77620_wdt.o > +obj-$(CONFIG_MAX77714_WATCHDOG) += max77714_wdt.o > obj-$(CONFIG_ZIIRAVE_WATCHDOG) += ziirave_wdt.o > obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o > obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o > diff --git a/drivers/watchdog/max77714_wdt.c b/drivers/watchdog/max77714_wdt.c > new file mode 100644 > index 000000000000..2d468db849f9 > --- /dev/null > +++ b/drivers/watchdog/max77714_wdt.c > @@ -0,0 +1,171 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Maxim MAX77714 Watchdog Driver > + * > + * Copyright (C) 2021 Luca Ceresoli > + * Author: Luca Ceresoli > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct max77714_wdt { > + struct device *dev; > + struct regmap *rmap; > + struct watchdog_device wd_dev; > +}; > + > +/* Timeout in seconds, indexed by TWD bits of CNFG_GLBL2 register */ > +unsigned int max77714_margin_value[] = { 2, 16, 64, 128 }; static > + > +static int max77714_wdt_start(struct watchdog_device *wd_dev) > +{ > + struct max77714_wdt *wdt = watchdog_get_drvdata(wd_dev); > + > + return regmap_update_bits(wdt->rmap, MAX77714_CNFG_GLBL2, > + MAX77714_WDTEN, MAX77714_WDTEN); > +} > + > +static int max77714_wdt_stop(struct watchdog_device *wd_dev) > +{ > + struct max77714_wdt *wdt = watchdog_get_drvdata(wd_dev); > + > + return regmap_update_bits(wdt->rmap, MAX77714_CNFG_GLBL2, > + MAX77714_WDTEN, 0); > +} > + > +static int max77714_wdt_ping(struct watchdog_device *wd_dev) > +{ > + struct max77714_wdt *wdt = watchdog_get_drvdata(wd_dev); > + > + return regmap_update_bits(wdt->rmap, MAX77714_CNFG_GLBL3, > + MAX77714_WDTC, 1); > +} > + > +static int max77714_wdt_set_timeout(struct watchdog_device *wd_dev, > + unsigned int timeout) > +{ > + struct max77714_wdt *wdt = watchdog_get_drvdata(wd_dev); > + unsigned int new_timeout, new_twd; > + int err; > + > + for (new_twd = 0; new_twd < ARRAY_SIZE(max77714_margin_value) - 1; new_twd++) > + if (timeout <= max77714_margin_value[new_twd]) > + break; > + > + /* new_wdt is not out of bounds here due to the "- 1" in the for loop */ > + new_timeout = max77714_margin_value[new_twd]; > + > + /* > + * "If the value of TWD needs to be changed, clear the system > + * watchdog timer first [...], then change the value of TWD." > + * (MAX77714 datasheet) > + */ > + err = regmap_update_bits(wdt->rmap, MAX77714_CNFG_GLBL3, > + MAX77714_WDTC, 1); > + if (err) > + return err; > + > + err = regmap_update_bits(wdt->rmap, MAX77714_CNFG_GLBL2, > + MAX77714_TWD_MASK, new_twd); > + if (err) > + return err; > + > + wd_dev->timeout = new_timeout; > + > + dev_dbg(wdt->dev, "New timeout = %u s (WDT = 0x%x)", new_timeout, new_twd); > + > + return 0; > +} > + > +static const struct watchdog_info max77714_wdt_info = { > + .identity = "max77714-watchdog", > + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, > +}; > + > +static const struct watchdog_ops max77714_wdt_ops = { > + .start = max77714_wdt_start, > + .stop = max77714_wdt_stop, > + .ping = max77714_wdt_ping, > + .set_timeout = max77714_wdt_set_timeout, > +}; > + > +static int max77714_wdt_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct max77714_wdt *wdt; > + struct watchdog_device *wd_dev; > + unsigned int regval; > + int err; > + > + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); > + if (!wdt) > + return -ENOMEM; > + > + wdt->dev = dev; > + > + wd_dev = &wdt->wd_dev; > + wd_dev->info = &max77714_wdt_info; > + wd_dev->ops = &max77714_wdt_ops; > + wd_dev->min_timeout = 2; > + wd_dev->max_timeout = 128; > + > + platform_set_drvdata(pdev, wdt); > + watchdog_set_drvdata(wd_dev, wdt); > + > + wdt->rmap = dev_get_regmap(dev->parent, NULL); > + if (!wdt->rmap) > + return dev_err_probe(wdt->dev, -ENODEV, "Failed to get parent regmap\n"); > + > + /* WD_RST_WK: if 1 wdog restarts; if 0 wdog shuts down */ > + err = regmap_update_bits(wdt->rmap, MAX77714_CNFG2_ONOFF, > + MAX77714_WD_RST_WK, MAX77714_WD_RST_WK); > + if (err) > + return dev_err_probe(wdt->dev, err, "Error updating CNFG2_ONOFF\n"); > + > + err = regmap_read(wdt->rmap, MAX77714_CNFG_GLBL2, ®val); > + if (err) > + return dev_err_probe(wdt->dev, err, "Error reading CNFG_GLBL2\n"); > + > + /* enable watchdog | enable auto-clear in sleep state */ > + regval |= (MAX77714_WDTEN | MAX77714_WDTSLPC); > + > + err = regmap_write(wdt->rmap, MAX77714_CNFG_GLBL2, regval); > + if (err) > + return dev_err_probe(wdt->dev, err, "Error writing CNFG_GLBL2\n"); > + > + wd_dev->timeout = max77714_margin_value[regval & MAX77714_TWD_MASK]; > + > + dev_dbg(wdt->dev, "Timeout = %u s (WDT = 0x%x)", > + wd_dev->timeout, regval & MAX77714_TWD_MASK); > + > + set_bit(WDOG_HW_RUNNING, &wd_dev->status); > + > + watchdog_stop_on_unregister(wd_dev); > + > + err = devm_watchdog_register_device(dev, wd_dev); > + if (err) > + return dev_err_probe(dev, err, "Cannot register watchdog device\n"); > + > + dev_info(dev, "registered as /dev/watchdog%d\n", wd_dev->id); > + > + return 0; > +} > + > +static struct platform_driver max77714_wdt_driver = { > + .driver = { > + .name = "max77714-watchdog", > + }, > + .probe = max77714_wdt_probe, > +}; > + > +module_platform_driver(max77714_wdt_driver); > + > +MODULE_DESCRIPTION("MAX77714 watchdog timer driver"); > +MODULE_AUTHOR("Luca Ceresoli "); > +MODULE_LICENSE("GPL v2"); >