rtc: watchdog support for rtc-m41t80 driver (617780d2) · Commits · e / devices / android_kernel_xiaomi_markw

drivers/rtc/Kconfig

+7 −0

Original line number	Diff line number	Diff line
		@@ -224,6 +224,13 @@ config RTC_DRV_M41T80
		This driver can also be built as a module. If so, the module
		will be called rtc-m41t80.

		config RTC_DRV_M41T80_WDT
		bool "ST M41T80 series RTC watchdog timer"
		depends on RTC_DRV_M41T80
		help
		If you say Y here you will get support for the
		watchdog timer in ST M41T80 RTC chips series.

		comment "SPI RTC drivers"
		depends on RTC_CLASS && SPI_MASTER

drivers/rtc/rtc-m41t80.c

+288 −0

Original line number	Diff line number	Diff line
		@@ -20,6 +20,13 @@
		#include <linux/i2c.h>
		#include <linux/rtc.h>
		#include <linux/bcd.h>
		#ifdef CONFIG_RTC_DRV_M41T80_WDT
		#include <linux/miscdevice.h>
		#include <linux/watchdog.h>
		#include <linux/reboot.h>
		#include <linux/fs.h>
		#include <linux/ioctl.h>
		#endif

		#define M41T80_REG_SSEC 0
		#define M41T80_REG_SEC 1
		@@ -480,6 +487,268 @@ static int m41t80_sysfs_register(struct device *dev)
		}
		#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 */

		/*
		*****************************************************************************
		*
		@@ -572,6 +841,19 @@ static int m41t80_probe(struct i2c_client *client)
		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:
		@@ -595,6 +877,12 @@ 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);