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Message-ID: <20140718140447.GA19013@roeck-us.net>
Date:	Fri, 18 Jul 2014 07:04:47 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	Andreas Werner <andreas.werner@....de>
Cc:	linux-kernel@...r.kernel.org, sameo@...ux.intel.com,
	lee.jones@...aro.org, cooloney@...il.com, rpurdie@...ys.net,
	linux-leds@...r.kernel.org, wim@...ana.be,
	linux-watchdog@...r.kernel.org
Subject: Re: [PATCH v3 2/3] drivers/watchdog/menf21bmc_wdt: introduce MEN
 14F021P00 BMC Watchdog driver

On Thu, Jul 17, 2014 at 03:18:31PM +0200, Andreas Werner wrote:
> Added driver to support the 14F021P00 BMC Watchdog.
> The BMC is a Board Management Controller including watchdog functionality.
> 
> This driver use the I2C interface to the BMC using the menf21bmc MFD Core driver.
> 
> Signed-off-by: Andreas Werner <andreas.werner@....de>

Only thing I dislike is continuation line alignment, where I really prefer
the 'official' style. That doesn't raise to the level of objection, though.

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

Guenter

> ---
>  drivers/watchdog/Kconfig         |   7 ++
>  drivers/watchdog/Makefile        |   1 +
>  drivers/watchdog/menf21bmc_wdt.c | 206 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 214 insertions(+)
>  create mode 100644 drivers/watchdog/menf21bmc_wdt.c
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 76dd541..f96431d 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -95,6 +95,13 @@ config GPIO_WATCHDOG
>  	  If you say yes here you get support for watchdog device
>  	  controlled through GPIO-line.
>  
> +config MENF21BMC_WATCHDOG
> +	tristate "MEN 14F021P00 BMC Watchdog"
> +	depends on MFD_MENF21BMC
> +	select WATCHDOG_CORE
> +	help
> +	  Say Y here to include support for the MEN 14F021P00 BMC Watchdog.
> +
>  config WM831X_WATCHDOG
>  	tristate "WM831x watchdog"
>  	depends on MFD_WM831X
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 468c320..de17014 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -178,3 +178,4 @@ obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
>  obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
>  obj-$(CONFIG_MAX63XX_WATCHDOG) += max63xx_wdt.o
>  obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
> +obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o
> diff --git a/drivers/watchdog/menf21bmc_wdt.c b/drivers/watchdog/menf21bmc_wdt.c
> new file mode 100644
> index 0000000..b46ee92
> --- /dev/null
> +++ b/drivers/watchdog/menf21bmc_wdt.c
> @@ -0,0 +1,206 @@
> +/*
> + *  MEN 14F021P00 Board Management Controller (BMC) Watchdog Driver.
> + *
> + *  Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
> + *  Author: Andreas Werner <andreas.werner@....de>
> + *  All rights reserved.
> + *
> + *  This program is free software; you can redistribute  it and/or modify it
> + *  under  the terms of  the GNU General  Public License as published by the
> + *  Free Software Foundation;  either version 2 of the  License, or (at your
> + *  option) any later version.
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/watchdog.h>
> +#include <linux/platform_device.h>
> +#include <linux/i2c.h>
> +
> +#define DEVNAME "menf21bmc_wdt"
> +
> +#define BMC_CMD_WD_ON		0x11
> +#define BMC_CMD_WD_OFF		0x12
> +#define BMC_CMD_WD_TRIG		0x13
> +#define BMC_CMD_WD_TIME		0x14
> +#define BMC_CMD_WD_STATE	0x17
> +#define BMC_WD_OFF_VAL		0x69
> +#define BMC_CMD_RST_RSN		0x92
> +
> +#define BMC_WD_TIMEOUT_MIN	1	/* in sec */
> +#define BMC_WD_TIMEOUT_MAX	6553	/* in sec */
> +
> +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 menf21bmc_wdt {
> +	struct watchdog_device wdt;
> +	struct i2c_client *i2c_client;
> +};
> +
> +static int menf21bmc_wdt_set_bootstatus(struct menf21bmc_wdt *data)
> +{
> +	int rst_rsn;
> +
> +	rst_rsn = i2c_smbus_read_byte_data(data->i2c_client, BMC_CMD_RST_RSN);
> +	if (rst_rsn < 0)
> +		return rst_rsn;
> +
> +	if (rst_rsn == 0x02)
> +		data->wdt.bootstatus |= WDIOF_CARDRESET;
> +	else if (rst_rsn == 0x05)
> +		data->wdt.bootstatus |= WDIOF_EXTERN1;
> +	else if (rst_rsn == 0x06)
> +		data->wdt.bootstatus |= WDIOF_EXTERN2;
> +	else if (rst_rsn == 0x0A)
> +		data->wdt.bootstatus |= WDIOF_POWERUNDER;
> +
> +	return 0;
> +}
> +
> +static int menf21bmc_wdt_start(struct watchdog_device *wdt)
> +{
> +	struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
> +
> +	return i2c_smbus_write_byte(drv_data->i2c_client, BMC_CMD_WD_ON);
> +}
> +
> +static int menf21bmc_wdt_stop(struct watchdog_device *wdt)
> +{
> +	struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
> +
> +	return i2c_smbus_write_byte_data(drv_data->i2c_client,
> +					BMC_CMD_WD_OFF, BMC_WD_OFF_VAL);
> +}
> +
> +static int
> +menf21bmc_wdt_settimeout(struct watchdog_device *wdt, unsigned int timeout)
> +{
> +	int ret;
> +	struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
> +
> +	/*
> +	 *  BMC Watchdog does have a resolution of 100ms.
> +	 *  Watchdog API defines the timeout in seconds, so we have to
> +	 *  multiply the value.
> +	 */
> +	ret = i2c_smbus_write_word_data(drv_data->i2c_client,
> +						BMC_CMD_WD_TIME, timeout * 10);
> +	if (ret < 0)
> +		return ret;
> +
> +	wdt->timeout = timeout;
> +
> +	return 0;
> +}
> +
> +static int menf21bmc_wdt_ping(struct watchdog_device *wdt)
> +{
> +	struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
> +
> +	return i2c_smbus_write_byte(drv_data->i2c_client, BMC_CMD_WD_TRIG);
> +}
> +
> +static const struct watchdog_info menf21bmc_wdt_info = {
> +	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
> +	.identity = DEVNAME,
> +};
> +
> +static const struct watchdog_ops menf21bmc_wdt_ops = {
> +	.owner		= THIS_MODULE,
> +	.start		= menf21bmc_wdt_start,
> +	.stop		= menf21bmc_wdt_stop,
> +	.ping		= menf21bmc_wdt_ping,
> +	.set_timeout	= menf21bmc_wdt_settimeout,
> +};
> +
> +static int menf21bmc_wdt_probe(struct platform_device *pdev)
> +{
> +	int ret, bmc_timeout;
> +	struct menf21bmc_wdt *drv_data;
> +	struct i2c_client *i2c_client = to_i2c_client(pdev->dev.parent);
> +
> +	drv_data = devm_kzalloc(&pdev->dev,
> +				sizeof(struct menf21bmc_wdt), GFP_KERNEL);
> +	if (!drv_data)
> +		return -ENOMEM;
> +
> +	drv_data->wdt.ops = &menf21bmc_wdt_ops;
> +	drv_data->wdt.info = &menf21bmc_wdt_info;
> +	drv_data->wdt.min_timeout = BMC_WD_TIMEOUT_MIN;
> +	drv_data->wdt.max_timeout = BMC_WD_TIMEOUT_MAX;
> +	drv_data->i2c_client = i2c_client;
> +
> +	/*
> +	 * Get the current wdt timeout value from the BMC because
> +	 * the BMC will save the value set before if the system restarts.
> +	 */
> +	bmc_timeout = i2c_smbus_read_word_data(drv_data->i2c_client,
> +							BMC_CMD_WD_TIME);
> +	if (bmc_timeout < 0) {
> +		dev_err(&pdev->dev, "failed to get current WDT timeout\n");
> +		return bmc_timeout;
> +	}
> +
> +	watchdog_init_timeout(&drv_data->wdt, bmc_timeout / 10, &pdev->dev);
> +	watchdog_set_nowayout(&drv_data->wdt, nowayout);
> +	watchdog_set_drvdata(&drv_data->wdt, drv_data);
> +	platform_set_drvdata(pdev, drv_data);
> +
> +	ret = menf21bmc_wdt_set_bootstatus(drv_data);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "failed to set Watchdog bootstatus\n");
> +		return ret;
> +	}
> +
> +	ret = watchdog_register_device(&drv_data->wdt);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to register Watchdog device\n");
> +		return ret;
> +	}
> +
> +	dev_info(&pdev->dev, "MEN 14F021P00 BMC Watchdog device enabled\n");
> +
> +	return 0;
> +}
> +
> +static int menf21bmc_wdt_remove(struct platform_device *pdev)
> +{
> +	struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev);
> +
> +	dev_warn(&pdev->dev,
> +		"Unregister MEN 14F021P00 BMC Watchdog device, board may reset\n");
> +
> +	watchdog_unregister_device(&drv_data->wdt);
> +
> +	return 0;
> +}
> +
> +static void menf21bmc_wdt_shutdown(struct platform_device *pdev)
> +{
> +	struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev);
> +
> +	i2c_smbus_write_word_data(drv_data->i2c_client,
> +					BMC_CMD_WD_OFF, BMC_WD_OFF_VAL);
> +}
> +
> +static struct  platform_driver menf21bmc_wdt = {
> +	.driver		= {
> +		.owner = THIS_MODULE,
> +		.name	= DEVNAME,
> +	},
> +	.probe		= menf21bmc_wdt_probe,
> +	.remove		= menf21bmc_wdt_remove,
> +	.shutdown	= menf21bmc_wdt_shutdown,
> +};
> +
> +module_platform_driver(menf21bmc_wdt);
> +
> +MODULE_DESCRIPTION("MEN 14F021P00 BMC Watchdog driver");
> +MODULE_AUTHOR("Andreas Werner <andreas.werner@....de>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:menf21bmc_wdt");
> -- 
> 2.0.1
> 
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