linux-kernel - Re: [PATCH v3 2/3] watchdog: Add ChromeOS EC-based watchdog driver

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Message-ID: <1e7b8590-7dc7-47a8-8105-6d01db627f85@kernel.org>
Date: Mon, 22 Jan 2024 11:31:47 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Lukasz Majczak <lma@...omium.org>, Gwendal Grignou
 <gwendal@...omium.org>, Tzung-Bi Shih <tzungbi@...nel.org>,
 Radoslaw Biernacki <biernacki@...gle.com>,
 Wim Van Sebroeck <wim@...ux-watchdog.org>, Lee Jones <lee@...nel.org>,
 Benson Leung <bleung@...omium.org>, Guenter Roeck <groeck@...omium.org>,
 linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
 chrome-platform@...ts.linux.dev
Subject: Re: [PATCH v3 2/3] watchdog: Add ChromeOS EC-based watchdog driver

On 19/01/2024 09:43, Lukasz Majczak wrote:
> Embedded Controller (EC) present on Chromebook devices
> can be used as a watchdog.
> Implement a driver to support it.
> 


..

> +static int cros_ec_wdt_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
> +	struct cros_ec_device *cros_ec = ec_dev->ec_dev;
> +	struct watchdog_device *wdd;
> +	union cros_ec_wdt_data arg;
> +	int ret = 0;
> +
> +	wdd = devm_kzalloc(&pdev->dev, sizeof(struct watchdog_device), GFP_KERNEL);

sizeof(*)

> +	if (!wdd)
> +		return -ENOMEM;
> +
> +	arg.req.command = EC_HANG_DETECT_CMD_GET_STATUS;
> +	ret = cros_ec_wdt_send_cmd(cros_ec, &arg);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to get watchdog bootstatus");
> +
> +	wdd->parent = &pdev->dev;
> +	wdd->info = &cros_ec_wdt_ident;
> +	wdd->ops = &cros_ec_wdt_ops;
> +	wdd->timeout = CROS_EC_WATCHDOG_DEFAULT_TIME;
> +	wdd->min_timeout = EC_HANG_DETECT_MIN_TIMEOUT;
> +	wdd->max_timeout = EC_HANG_DETECT_MAX_TIMEOUT;
> +	if (arg.resp.status == EC_HANG_DETECT_AP_BOOT_EC_WDT)
> +		wdd->bootstatus = WDIOF_CARDRESET;
> +
> +	arg.req.command = EC_HANG_DETECT_CMD_CLEAR_STATUS;
> +	ret = cros_ec_wdt_send_cmd(cros_ec, &arg);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to clear watchdog bootstatus");
> +
> +	watchdog_stop_on_reboot(wdd);
> +	watchdog_stop_on_unregister(wdd);
> +	watchdog_set_drvdata(wdd, cros_ec);
> +	platform_set_drvdata(pdev, wdd);
> +
> +	return devm_watchdog_register_device(dev, wdd);
> +}
> +
> +static int __maybe_unused cros_ec_wdt_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> +	struct watchdog_device *wdd = platform_get_drvdata(pdev);
> +	int ret = 0;
> +
> +	if (watchdog_active(wdd))
> +		ret = cros_ec_wdt_stop(wdd);
> +
> +	return ret;
> +}
> +
> +static int __maybe_unused cros_ec_wdt_resume(struct platform_device *pdev)
> +{
> +	struct watchdog_device *wdd = platform_get_drvdata(pdev);
> +	int ret = 0;
> +
> +	if (watchdog_active(wdd))
> +		ret = cros_ec_wdt_start(wdd);
> +
> +	return ret;
> +}
> +
> +static struct platform_driver cros_ec_wdt_driver = {
> +	.probe		= cros_ec_wdt_probe,
> +	.suspend	= pm_ptr(cros_ec_wdt_suspend),
> +	.resume		= pm_ptr(cros_ec_wdt_resume),
> +	.driver		= {
> +		.name	= DRV_NAME,
> +	},
> +};
> +
> +module_platform_driver(cros_ec_wdt_driver);
> +
> +static const struct platform_device_id cros_ec_wdt_id[] = {
> +	{ DRV_NAME, 0 },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(platform, cros_ec_wdt_id);

device_id is not placed here, please open existing drivers for
reference. Why this isn't referenced in driver structure?

> +MODULE_DESCRIPTION("Cros EC Watchdog Device Driver");
> +MODULE_LICENSE("GPL");

Best regards,
Krzysztof