rtc-m41t80.c

linux 内核源代码

	    i2c_smbus_write_byte_data(client, M41T80_REG_SQW, sqw) < 0)
		return -EIO;
	if (val && i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
					     almon | M41T80_ALMON_SQWE) < 0)
		return -EIO;
	return count;
}
static DEVICE_ATTR(sqwfreq, S_IRUGO | S_IWUSR,
		   m41t80_sysfs_show_sqwfreq, m41t80_sysfs_set_sqwfreq);

static struct attribute *attrs[] = {
	&dev_attr_flags.attr,
	&dev_attr_sqwfreq.attr,
	NULL,
};
static struct attribute_group attr_group = {
	.attrs = attrs,
};

static int m41t80_sysfs_register(struct device *dev)
{
	return sysfs_create_group(&dev->kobj, &attr_group);
}
#else
static int m41t80_sysfs_register(struct device *dev)
{
	return 0;
}
#endif

#ifdef CONFIG_RTC_DRV_M41T80_WDT
/*
 *****************************************************************************
 *
 * Watchdog Driver
 *
 *****************************************************************************
 */
static struct i2c_client *save_client;

/* Default margin */
#define WD_TIMO 60		/* 1..31 seconds */

static int wdt_margin = WD_TIMO;
module_param(wdt_margin, int, 0);
MODULE_PARM_DESC(wdt_margin, "Watchdog timeout in seconds (default 60s)");

static unsigned long wdt_is_open;
static int boot_flag;

/**
 *	wdt_ping:
 *
 *	Reload counter one with the watchdog timeout. We don't bother reloading
 *	the cascade counter.
 */
static void wdt_ping(void)
{
	unsigned char i2c_data[2];
	struct i2c_msg msgs1[1] = {
		{
			.addr	= save_client->addr,
			.flags	= 0,
			.len	= 2,
			.buf	= i2c_data,
		},
	};
	i2c_data[0] = 0x09;		/* watchdog register */

	if (wdt_margin > 31)
		i2c_data[1] = (wdt_margin & 0xFC) | 0x83; /* resolution = 4s */
	else
		/*
		 * WDS = 1 (0x80), mulitplier = WD_TIMO, resolution = 1s (0x02)
		 */
		i2c_data[1] = wdt_margin<<2 | 0x82;

	i2c_transfer(save_client->adapter, msgs1, 1);
}

/**
 *	wdt_disable:
 *
 *	disables watchdog.
 */
static void wdt_disable(void)
{
	unsigned char i2c_data[2], i2c_buf[0x10];
	struct i2c_msg msgs0[2] = {
		{
			.addr	= save_client->addr,
			.flags	= 0,
			.len	= 1,
			.buf	= i2c_data,
		},
		{
			.addr	= save_client->addr,
			.flags	= I2C_M_RD,
			.len	= 1,
			.buf	= i2c_buf,
		},
	};
	struct i2c_msg msgs1[1] = {
		{
			.addr	= save_client->addr,
			.flags	= 0,
			.len	= 2,
			.buf	= i2c_data,
		},
	};

	i2c_data[0] = 0x09;
	i2c_transfer(save_client->adapter, msgs0, 2);

	i2c_data[0] = 0x09;
	i2c_data[1] = 0x00;
	i2c_transfer(save_client->adapter, msgs1, 1);
}

/**
 *	wdt_write:
 *	@file: file handle to the watchdog
 *	@buf: buffer to write (unused as data does not matter here
 *	@count: count of bytes
 *	@ppos: pointer to the position to write. No seeks allowed
 *
 *	A write to a watchdog device is defined as a keepalive signal. Any
 *	write of data will do, as we we don't define content meaning.
 */
static ssize_t wdt_write(struct file *file, const char __user *buf,
			 size_t count, loff_t *ppos)
{
	/*  Can't seek (pwrite) on this device
	if (ppos != &file->f_pos)
	return -ESPIPE;
	*/
	if (count) {
		wdt_ping();
		return 1;
	}
	return 0;
}

static ssize_t wdt_read(struct file *file, char __user *buf,
			size_t count, loff_t *ppos)
{
	return 0;
}

/**
 *	wdt_ioctl:
 *	@inode: inode of the device
 *	@file: file handle to the device
 *	@cmd: watchdog command
 *	@arg: argument pointer
 *
 *	The watchdog API defines a common set of functions for all watchdogs
 *	according to their available features. We only actually usefully support
 *	querying capabilities and current status.
 */
static int wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
		     unsigned long arg)
{
	int new_margin, rv;
	static struct watchdog_info ident = {
		.options = WDIOF_POWERUNDER | WDIOF_KEEPALIVEPING |
			WDIOF_SETTIMEOUT,
		.firmware_version = 1,
		.identity = "M41T80 WTD"
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user((struct watchdog_info __user *)arg, &ident,
				    sizeof(ident)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		return put_user(boot_flag, (int __user *)arg);
	case WDIOC_KEEPALIVE:
		wdt_ping();
		return 0;
	case WDIOC_SETTIMEOUT:
		if (get_user(new_margin, (int __user *)arg))
			return -EFAULT;
		/* Arbitrary, can't find the card's limits */
		if (new_margin < 1 || new_margin > 124)
			return -EINVAL;
		wdt_margin = new_margin;
		wdt_ping();
		/* Fall */
	case WDIOC_GETTIMEOUT:
		return put_user(wdt_margin, (int __user *)arg);

	case WDIOC_SETOPTIONS:
		if (copy_from_user(&rv, (int __user *)arg, sizeof(int)))
			return -EFAULT;

		if (rv & WDIOS_DISABLECARD) {
			printk(KERN_INFO
			       "rtc-m41t80: disable watchdog\n");
			wdt_disable();
		}

		if (rv & WDIOS_ENABLECARD) {
			printk(KERN_INFO
			       "rtc-m41t80: enable watchdog\n");
			wdt_ping();
		}

		return -EINVAL;
	}
	return -ENOTTY;
}

/**
 *	wdt_open:
 *	@inode: inode of device
 *	@file: file handle to device
 *
 */
static int wdt_open(struct inode *inode, struct file *file)
{
	if (MINOR(inode->i_rdev) == WATCHDOG_MINOR) {
		if (test_and_set_bit(0, &wdt_is_open))
			return -EBUSY;
		/*
		 *	Activate
		 */
		wdt_is_open = 1;
		return 0;
	}
	return -ENODEV;
}

/**
 *	wdt_close:
 *	@inode: inode to board
 *	@file: file handle to board
 *
 */
static int wdt_release(struct inode *inode, struct file *file)
{
	if (MINOR(inode->i_rdev) == WATCHDOG_MINOR)
		clear_bit(0, &wdt_is_open);
	return 0;
}

/**
 *	notify_sys:
 *	@this: our notifier block
 *	@code: the event being reported
 *	@unused: unused
 *
 *	Our notifier is called on system shutdowns. We want to turn the card
 *	off at reboot otherwise the machine will reboot again during memory
 *	test or worse yet during the following fsck. This would suck, in fact
 *	trust me - if it happens it does suck.
 */
static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
			  void *unused)
{
	if (code == SYS_DOWN || code == SYS_HALT)
		/* Disable Watchdog */
		wdt_disable();
	return NOTIFY_DONE;
}

static const struct file_operations wdt_fops = {
	.owner	= THIS_MODULE,
	.read	= wdt_read,
	.ioctl	= wdt_ioctl,
	.write	= wdt_write,
	.open	= wdt_open,
	.release = wdt_release,
};

static struct miscdevice wdt_dev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &wdt_fops,
};

/*
 *	The WDT card needs to learn about soft shutdowns in order to
 *	turn the timebomb registers off.
 */
static struct notifier_block wdt_notifier = {
	.notifier_call = wdt_notify_sys,
};
#endif /* CONFIG_RTC_DRV_M41T80_WDT */

/*
 *****************************************************************************
 *
 *	Driver Interface
 *
 *****************************************************************************
 */
static int m41t80_probe(struct i2c_client *client)
{
	int i, rc = 0;
	struct rtc_device *rtc = NULL;
	struct rtc_time tm;
	const struct m41t80_chip_info *chip;
	struct m41t80_data *clientdata = NULL;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C
				     | I2C_FUNC_SMBUS_BYTE_DATA)) {
		rc = -ENODEV;
		goto exit;
	}

	dev_info(&client->dev,
		 "chip found, driver version " DRV_VERSION "\n");

	chip = NULL;
	for (i = 0; i < ARRAY_SIZE(m41t80_chip_info_tbl); i++) {
		if (!strcmp(m41t80_chip_info_tbl[i].name, client->name)) {
			chip = &m41t80_chip_info_tbl[i];
			break;
		}
	}
	if (!chip) {
		dev_err(&client->dev, "%s is not supported\n", client->name);
		rc = -ENODEV;
		goto exit;
	}

	clientdata = kzalloc(sizeof(*clientdata), GFP_KERNEL);
	if (!clientdata) {
		rc = -ENOMEM;
		goto exit;
	}

	rtc = rtc_device_register(client->name, &client->dev,
				  &m41t80_rtc_ops, THIS_MODULE);
	if (IS_ERR(rtc)) {
		rc = PTR_ERR(rtc);
		rtc = NULL;
		goto exit;
	}

	clientdata->rtc = rtc;
	clientdata->chip = chip;
	i2c_set_clientdata(client, clientdata);

	/* Make sure HT (Halt Update) bit is cleared */
	rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
	if (rc < 0)
		goto ht_err;

	if (rc & M41T80_ALHOUR_HT) {
		if (chip->features & M41T80_FEATURE_HT) {
			m41t80_get_datetime(client, &tm);
			dev_info(&client->dev, "HT bit was set!\n");
			dev_info(&client->dev,
				 "Power Down at "
				 "%04i-%02i-%02i %02i:%02i:%02i\n",
				 tm.tm_year + 1900,
				 tm.tm_mon + 1, tm.tm_mday, tm.tm_hour,
				 tm.tm_min, tm.tm_sec);
		}
		if (i2c_smbus_write_byte_data(client,
					      M41T80_REG_ALARM_HOUR,
					      rc & ~M41T80_ALHOUR_HT) < 0)
			goto ht_err;
	}

	/* Make sure ST (stop) bit is cleared */
	rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
	if (rc < 0)
		goto st_err;

	if (rc & M41T80_SEC_ST) {
		if (i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
					      rc & ~M41T80_SEC_ST) < 0)
			goto st_err;
	}

	rc = m41t80_sysfs_register(&client->dev);
	if (rc)
		goto exit;

#ifdef CONFIG_RTC_DRV_M41T80_WDT
	if (chip->features & M41T80_FEATURE_HT) {
		rc = misc_register(&wdt_dev);
		if (rc)
			goto exit;
		rc = register_reboot_notifier(&wdt_notifier);
		if (rc) {
			misc_deregister(&wdt_dev);
			goto exit;
		}
		save_client = client;
	}
#endif
	return 0;

st_err:
	rc = -EIO;
	dev_err(&client->dev, "Can't clear ST bit\n");
	goto exit;
ht_err:
	rc = -EIO;
	dev_err(&client->dev, "Can't clear HT bit\n");
	goto exit;

exit:
	if (rtc)
		rtc_device_unregister(rtc);
	kfree(clientdata);
	return rc;
}

static int m41t80_remove(struct i2c_client *client)
{
	struct m41t80_data *clientdata = i2c_get_clientdata(client);
	struct rtc_device *rtc = clientdata->rtc;

#ifdef CONFIG_RTC_DRV_M41T80_WDT
	if (clientdata->chip->features & M41T80_FEATURE_HT) {
		misc_deregister(&wdt_dev);
		unregister_reboot_notifier(&wdt_notifier);
	}
#endif
	if (rtc)
		rtc_device_unregister(rtc);
	kfree(clientdata);

	return 0;
}

static struct i2c_driver m41t80_driver = {
	.driver = {
		.name = "rtc-m41t80",
	},
	.probe = m41t80_probe,
	.remove = m41t80_remove,
};

static int __init m41t80_rtc_init(void)
{
	return i2c_add_driver(&m41t80_driver);
}

static void __exit m41t80_rtc_exit(void)
{
	i2c_del_driver(&m41t80_driver);
}

MODULE_AUTHOR("Alexander Bigga <[e-mail]>");
MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VERSION);

module_init(m41t80_rtc_init);
module_exit(m41t80_rtc_exit);