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Date: Sun, 17 Jul 2016 22:06:14 +0200
From: Wim Van Sebroeck <wim@...ana.be>
To: Laxman Dewangan <ldewangan@...dia.com>
Cc: linux@...ck-us.net, linux-kernel@...r.kernel.org,
linux-watchdog@...r.kernel.org
Subject: Re: [PATCH V4] watchdog: max77620: Add support for watchdog timer
Hi Laxman,
> Maxim PMIC MAX77620 is Power management IC which have multiple
> sub blocks like regulators (DCDC/LDOs), GPIO, RTC, Clock, Watchdog
> timer etc.
>
> Add the driver for watchdog timer under watchdog framework.
> The driver implements the watchdog callbacks to start, stop,
> ping and set timeout for watchodg framework.
>
> Signed-off-by: Laxman Dewangan <ldewangan@...dia.com>
> Reviewed-by: Guenter Roeck <linux@...ck-us.net>
>
> ---
> Changes from V1:
> - Remove the error prints from start/stop/ping to simplify the function.
> - Instead of stopping running WDT, inform HW RUNNING and update the required
> param accordingly.
> - Resequence the param sets for wdt device to avoid race condition, move all
> wdt device setting before registration.
>
> Changes from V2:
> - Set timeout regardless of WDT running or not in probe.
>
> Changes from V3:
> - Fix typo in comment.
> ---
> drivers/watchdog/Kconfig | 9 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/max77620_wdt.c | 227 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 237 insertions(+)
> create mode 100644 drivers/watchdog/max77620_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index b54f26c..ca0602d 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -516,6 +516,15 @@ config MAX63XX_WATCHDOG
> help
> Support for memory mapped max63{69,70,71,72,73,74} watchdog timer.
>
> +config MAX77620_WATCHDOG
> + tristate "Maxim Max77620 Watchdog Timer"
> + depends on MFD_MAX77620
> + help
> + This is the driver for the Max77620 watchdog timer.
> + Say 'Y' here to enable the watchdog timer support for
> + MAX77620 chips. To compile this driver as a module,
> + choose M here: the module will be called max77620_wdt.
> +
> config IMX2_WDT
> tristate "IMX2+ Watchdog"
> depends on ARCH_MXC || ARCH_LAYERSCAPE
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index a46e7c1..5d38173 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -203,6 +203,7 @@ obj-$(CONFIG_TANGOX_WATCHDOG) += tangox_wdt.o
> obj-$(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_ZIIRAVE_WATCHDOG) += ziirave_wdt.o
> obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
> obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o
> diff --git a/drivers/watchdog/max77620_wdt.c b/drivers/watchdog/max77620_wdt.c
> new file mode 100644
> index 0000000..48b84df
> --- /dev/null
> +++ b/drivers/watchdog/max77620_wdt.c
> @@ -0,0 +1,227 @@
> +/*
> + * Maxim MAX77620 Watchdog Driver
> + *
> + * Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
> + *
> + * Author: Laxman Dewangan <ldewangan@...dia.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.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mfd/max77620.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/watchdog.h>
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +
> +struct max77620_wdt {
> + struct device *dev;
> + struct regmap *rmap;
> + struct watchdog_device wdt_dev;
> +};
> +
> +static int max77620_wdt_start(struct watchdog_device *wdt_dev)
> +{
> + struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
> + MAX77620_WDTEN, MAX77620_WDTEN);
> +}
> +
> +static int max77620_wdt_stop(struct watchdog_device *wdt_dev)
> +{
> + struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
> + MAX77620_WDTEN, 0);
> +}
> +
> +static int max77620_wdt_ping(struct watchdog_device *wdt_dev)
> +{
> + struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + return regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL3,
> + MAX77620_WDTC_MASK, 0x1);
> +}
> +
> +static int max77620_wdt_set_timeout(struct watchdog_device *wdt_dev,
> + unsigned int timeout)
> +{
> + struct max77620_wdt *wdt = watchdog_get_drvdata(wdt_dev);
> + unsigned int wdt_timeout;
> + u8 regval;
> + int ret;
> +
> + switch (timeout) {
> + case 0 ... 2:
> + regval = MAX77620_TWD_2s;
> + wdt_timeout = 2;
> + break;
> +
> + case 3 ... 16:
> + regval = MAX77620_TWD_16s;
> + wdt_timeout = 16;
> + break;
> +
> + case 17 ... 64:
> + regval = MAX77620_TWD_64s;
> + wdt_timeout = 64;
> + break;
> +
> + default:
> + regval = MAX77620_TWD_128s;
> + wdt_timeout = 128;
> + break;
> + }
> +
> + ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL3,
> + MAX77620_WDTC_MASK, 0x1);
> + if (ret < 0)
> + return ret;
> +
> + ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
> + MAX77620_TWD_MASK, regval);
> + if (ret < 0)
> + return ret;
> +
> + wdt_dev->timeout = wdt_timeout;
> +
> + return 0;
> +}
> +
> +static const struct watchdog_info max77620_wdt_info = {
> + .identity = "max77620-watchdog",
> + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
> +};
> +
> +static const struct watchdog_ops max77620_wdt_ops = {
> + .start = max77620_wdt_start,
> + .stop = max77620_wdt_stop,
> + .ping = max77620_wdt_ping,
> + .set_timeout = max77620_wdt_set_timeout,
> +};
> +
> +static int max77620_wdt_probe(struct platform_device *pdev)
> +{
> + struct max77620_wdt *wdt;
> + struct watchdog_device *wdt_dev;
> + unsigned int regval;
> + int ret;
> +
> + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
> + if (!wdt)
> + return -ENOMEM;
> +
> + wdt->dev = &pdev->dev;
> + wdt->rmap = dev_get_regmap(pdev->dev.parent, NULL);
> + if (!wdt->rmap) {
> + dev_err(wdt->dev, "Failed to get parent regmap\n");
> + return -ENODEV;
> + }
> +
> + wdt_dev = &wdt->wdt_dev;
> + wdt_dev->info = &max77620_wdt_info;
> + wdt_dev->ops = &max77620_wdt_ops;
> + wdt_dev->min_timeout = 2;
> + wdt_dev->max_timeout = 128;
> + wdt_dev->max_hw_heartbeat_ms = 128 * 1000;
> +
> + platform_set_drvdata(pdev, wdt);
> +
> + /* Enable WD_RST_WK - WDT expire results in a restart */
> + ret = regmap_update_bits(wdt->rmap, MAX77620_REG_ONOFFCNFG2,
> + MAX77620_ONOFFCNFG2_WD_RST_WK,
> + MAX77620_ONOFFCNFG2_WD_RST_WK);
> + if (ret < 0) {
> + dev_err(wdt->dev, "Failed to set WD_RST_WK: %d\n", ret);
> + return ret;
> + }
> +
> + /* Set WDT clear in OFF and sleep mode */
> + ret = regmap_update_bits(wdt->rmap, MAX77620_REG_CNFGGLBL2,
> + MAX77620_WDTOFFC | MAX77620_WDTSLPC,
> + MAX77620_WDTOFFC | MAX77620_WDTSLPC);
> + if (ret < 0) {
> + dev_err(wdt->dev, "Failed to set WDT OFF mode: %d\n", ret);
> + return ret;
> + }
> +
> + /* Check if WDT running and if yes then set flags properly */
> + ret = regmap_read(wdt->rmap, MAX77620_REG_CNFGGLBL2, ®val);
> + if (ret < 0) {
> + dev_err(wdt->dev, "Failed to read WDT CFG register: %d\n", ret);
> + return ret;
> + }
> +
> + switch (regval & MAX77620_TWD_MASK) {
> + case MAX77620_TWD_2s:
> + wdt_dev->timeout = 2;
> + break;
> + case MAX77620_TWD_16s:
> + wdt_dev->timeout = 16;
> + break;
> + case MAX77620_TWD_64s:
> + wdt_dev->timeout = 64;
> + break;
> + default:
> + wdt_dev->timeout = 128;
> + break;
> + }
> +
> + if (regval & MAX77620_WDTEN)
> + set_bit(WDOG_HW_RUNNING, &wdt_dev->status);
> +
> + watchdog_set_nowayout(wdt_dev, nowayout);
> + watchdog_set_drvdata(wdt_dev, wdt);
> +
> + ret = watchdog_register_device(wdt_dev);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "watchdog registration failed: %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int max77620_wdt_remove(struct platform_device *pdev)
> +{
> + struct max77620_wdt *wdt = platform_get_drvdata(pdev);
> +
> + max77620_wdt_stop(&wdt->wdt_dev);
> + watchdog_unregister_device(&wdt->wdt_dev);
> +
> + return 0;
> +}
> +
> +static struct platform_device_id max77620_wdt_devtype[] = {
> + { .name = "max77620-watchdog", },
> + { },
> +};
> +
> +static struct platform_driver max77620_wdt_driver = {
> + .driver = {
> + .name = "max77620-watchdog",
> + },
> + .probe = max77620_wdt_probe,
> + .remove = max77620_wdt_remove,
> + .id_table = max77620_wdt_devtype,
> +};
> +
> +module_platform_driver(max77620_wdt_driver);
> +
> +MODULE_DESCRIPTION("Max77620 watchdog timer driver");
> +
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
> + "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +MODULE_AUTHOR("Laxman Dewangan <ldewangan@...dia.com>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.1.4
>
This patch has been added to linux-watchdog-next.
Kind regards,
Wim.
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