linux/drivers/rtc/rtc-m41t80.c

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/*
* I2C client/driver for the ST M41T80 family of i2c rtc chips.
*
* Author: Alexander Bigga <ab@mycable.de>
*
* Based on m41t00.c by Mark A. Greer <mgreer@mvista.com>
*
* 2006 (c) mycable GmbH
*
* 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.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/bcd.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/rtc.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/string.h>
#ifdef CONFIG_RTC_DRV_M41T80_WDT
#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/miscdevice.h>
#include <linux/reboot.h>
#include <linux/watchdog.h>
#endif
#define M41T80_REG_SSEC 0x00
#define M41T80_REG_SEC 0x01
#define M41T80_REG_MIN 0x02
#define M41T80_REG_HOUR 0x03
#define M41T80_REG_WDAY 0x04
#define M41T80_REG_DAY 0x05
#define M41T80_REG_MON 0x06
#define M41T80_REG_YEAR 0x07
#define M41T80_REG_ALARM_MON 0x0a
#define M41T80_REG_ALARM_DAY 0x0b
#define M41T80_REG_ALARM_HOUR 0x0c
#define M41T80_REG_ALARM_MIN 0x0d
#define M41T80_REG_ALARM_SEC 0x0e
#define M41T80_REG_FLAGS 0x0f
#define M41T80_REG_SQW 0x13
#define M41T80_DATETIME_REG_SIZE (M41T80_REG_YEAR + 1)
#define M41T80_ALARM_REG_SIZE \
(M41T80_REG_ALARM_SEC + 1 - M41T80_REG_ALARM_MON)
#define M41T80_SEC_ST BIT(7) /* ST: Stop Bit */
#define M41T80_ALMON_AFE BIT(7) /* AFE: AF Enable Bit */
#define M41T80_ALMON_SQWE BIT(6) /* SQWE: SQW Enable Bit */
#define M41T80_ALHOUR_HT BIT(6) /* HT: Halt Update Bit */
#define M41T80_FLAGS_OF BIT(2) /* OF: Oscillator Failure Bit */
#define M41T80_FLAGS_AF BIT(6) /* AF: Alarm Flag Bit */
#define M41T80_FLAGS_BATT_LOW BIT(4) /* BL: Battery Low Bit */
#define M41T80_WATCHDOG_RB2 BIT(7) /* RB: Watchdog resolution */
#define M41T80_WATCHDOG_RB1 BIT(1) /* RB: Watchdog resolution */
#define M41T80_WATCHDOG_RB0 BIT(0) /* RB: Watchdog resolution */
#define M41T80_FEATURE_HT BIT(0) /* Halt feature */
#define M41T80_FEATURE_BL BIT(1) /* Battery low indicator */
#define M41T80_FEATURE_SQ BIT(2) /* Squarewave feature */
#define M41T80_FEATURE_WD BIT(3) /* Extra watchdog resolution */
#define M41T80_FEATURE_SQ_ALT BIT(4) /* RSx bits are in reg 4 */
static DEFINE_MUTEX(m41t80_rtc_mutex);
static const struct i2c_device_id m41t80_id[] = {
{ "m41t62", M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT },
{ "m41t65", M41T80_FEATURE_HT | M41T80_FEATURE_WD },
{ "m41t80", M41T80_FEATURE_SQ },
{ "m41t81", M41T80_FEATURE_HT | M41T80_FEATURE_SQ},
{ "m41t81s", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
{ "m41t82", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
{ "m41t83", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
{ "m41st84", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
{ "m41st85", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
{ "m41st87", M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ },
{ "rv4162", M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT },
{ }
};
MODULE_DEVICE_TABLE(i2c, m41t80_id);
static const struct of_device_id m41t80_of_match[] = {
{
.compatible = "st,m41t62",
.data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_SQ_ALT)
},
{
.compatible = "st,m41t65",
.data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_WD)
},
{
.compatible = "st,m41t80",
.data = (void *)(M41T80_FEATURE_SQ)
},
{
.compatible = "st,m41t81",
.data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_SQ)
},
{
.compatible = "st,m41t81s",
.data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
},
{
.compatible = "st,m41t82",
.data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
},
{
.compatible = "st,m41t83",
.data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
},
{
.compatible = "st,m41t84",
.data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
},
{
.compatible = "st,m41t85",
.data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
},
{
.compatible = "st,m41t87",
.data = (void *)(M41T80_FEATURE_HT | M41T80_FEATURE_BL | M41T80_FEATURE_SQ)
},
{
.compatible = "microcrystal,rv4162",
.data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
},
/* DT compatibility only, do not use compatibles below: */
{
.compatible = "st,rv4162",
.data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
},
{
.compatible = "rv4162",
.data = (void *)(M41T80_FEATURE_SQ | M41T80_FEATURE_WD | M41T80_FEATURE_SQ_ALT)
},
{ }
};
MODULE_DEVICE_TABLE(of, m41t80_of_match);
struct m41t80_data {
unsigned long features;
struct rtc_device *rtc;
};
static irqreturn_t m41t80_handle_irq(int irq, void *dev_id)
{
struct i2c_client *client = dev_id;
struct m41t80_data *m41t80 = i2c_get_clientdata(client);
struct mutex *lock = &m41t80->rtc->ops_lock;
unsigned long events = 0;
int flags, flags_afe;
mutex_lock(lock);
flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
if (flags_afe < 0) {
mutex_unlock(lock);
return IRQ_NONE;
}
flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
if (flags <= 0) {
mutex_unlock(lock);
return IRQ_NONE;
}
if (flags & M41T80_FLAGS_AF) {
flags &= ~M41T80_FLAGS_AF;
flags_afe &= ~M41T80_ALMON_AFE;
events |= RTC_AF;
}
if (events) {
rtc_update_irq(m41t80->rtc, 1, events);
i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS, flags);
i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
flags_afe);
}
mutex_unlock(lock);
return IRQ_HANDLED;
}
static int m41t80_get_datetime(struct i2c_client *client,
struct rtc_time *tm)
{
unsigned char buf[8];
int err, flags;
flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
if (flags < 0)
return flags;
if (flags & M41T80_FLAGS_OF) {
dev_err(&client->dev, "Oscillator failure, data is invalid.\n");
return -EINVAL;
}
err = i2c_smbus_read_i2c_block_data(client, M41T80_REG_SSEC,
sizeof(buf), buf);
if (err < 0) {
dev_err(&client->dev, "Unable to read date\n");
return -EIO;
}
tm->tm_sec = bcd2bin(buf[M41T80_REG_SEC] & 0x7f);
tm->tm_min = bcd2bin(buf[M41T80_REG_MIN] & 0x7f);
tm->tm_hour = bcd2bin(buf[M41T80_REG_HOUR] & 0x3f);
tm->tm_mday = bcd2bin(buf[M41T80_REG_DAY] & 0x3f);
tm->tm_wday = buf[M41T80_REG_WDAY] & 0x07;
tm->tm_mon = bcd2bin(buf[M41T80_REG_MON] & 0x1f) - 1;
/* assume 20YY not 19YY, and ignore the Century Bit */
tm->tm_year = bcd2bin(buf[M41T80_REG_YEAR]) + 100;
return rtc_valid_tm(tm);
}
/* Sets the given date and time to the real time clock. */
static int m41t80_set_datetime(struct i2c_client *client, struct rtc_time *tm)
{
struct m41t80_data *clientdata = i2c_get_clientdata(client);
unsigned char buf[8];
int err, flags;
if (tm->tm_year < 100 || tm->tm_year > 199)
return -EINVAL;
buf[M41T80_REG_SSEC] = 0;
buf[M41T80_REG_SEC] = bin2bcd(tm->tm_sec);
buf[M41T80_REG_MIN] = bin2bcd(tm->tm_min);
buf[M41T80_REG_HOUR] = bin2bcd(tm->tm_hour);
buf[M41T80_REG_DAY] = bin2bcd(tm->tm_mday);
buf[M41T80_REG_MON] = bin2bcd(tm->tm_mon + 1);
buf[M41T80_REG_YEAR] = bin2bcd(tm->tm_year - 100);
buf[M41T80_REG_WDAY] = tm->tm_wday;
/* If the square wave output is controlled in the weekday register */
if (clientdata->features & M41T80_FEATURE_SQ_ALT) {
int val;
val = i2c_smbus_read_byte_data(client, M41T80_REG_WDAY);
if (val < 0)
return val;
buf[M41T80_REG_WDAY] |= (val & 0xf0);
}
err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_SSEC,
sizeof(buf), buf);
if (err < 0) {
dev_err(&client->dev, "Unable to write to date registers\n");
return err;
}
/* Clear the OF bit of Flags Register */
flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
if (flags < 0)
return flags;
if (i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
flags & ~M41T80_FLAGS_OF)) {
dev_err(&client->dev, "Unable to write flags register\n");
return -EIO;
}
return err;
}
static int m41t80_rtc_proc(struct device *dev, struct seq_file *seq)
{
struct i2c_client *client = to_i2c_client(dev);
struct m41t80_data *clientdata = i2c_get_clientdata(client);
u8 reg;
if (clientdata->features & M41T80_FEATURE_BL) {
reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
seq_printf(seq, "battery\t\t: %s\n",
(reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
}
return 0;
}
static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
return m41t80_get_datetime(to_i2c_client(dev), tm);
}
static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
return m41t80_set_datetime(to_i2c_client(dev), tm);
}
static int m41t80_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct i2c_client *client = to_i2c_client(dev);
int flags, retval;
flags = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
if (flags < 0)
return flags;
if (enabled)
flags |= M41T80_ALMON_AFE;
else
flags &= ~M41T80_ALMON_AFE;
retval = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, flags);
if (retval < 0) {
dev_err(dev, "Unable to enable alarm IRQ %d\n", retval);
return retval;
}
return 0;
}
static int m41t80_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct i2c_client *client = to_i2c_client(dev);
u8 alarmvals[5];
int ret, err;
alarmvals[0] = bin2bcd(alrm->time.tm_mon + 1);
alarmvals[1] = bin2bcd(alrm->time.tm_mday);
alarmvals[2] = bin2bcd(alrm->time.tm_hour);
alarmvals[3] = bin2bcd(alrm->time.tm_min);
alarmvals[4] = bin2bcd(alrm->time.tm_sec);
/* Clear AF and AFE flags */
ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
if (ret < 0)
return ret;
err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
ret & ~(M41T80_ALMON_AFE));
if (err < 0) {
dev_err(dev, "Unable to clear AFE bit\n");
return err;
}
/* Keep SQWE bit value */
alarmvals[0] |= (ret & M41T80_ALMON_SQWE);
ret = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
if (ret < 0)
return ret;
err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
ret & ~(M41T80_FLAGS_AF));
if (err < 0) {
dev_err(dev, "Unable to clear AF bit\n");
return err;
}
/* Write the alarm */
err = i2c_smbus_write_i2c_block_data(client, M41T80_REG_ALARM_MON,
5, alarmvals);
if (err)
return err;
/* Enable the alarm interrupt */
if (alrm->enabled) {
alarmvals[0] |= M41T80_ALMON_AFE;
err = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
alarmvals[0]);
if (err)
return err;
}
return 0;
}
static int m41t80_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct i2c_client *client = to_i2c_client(dev);
u8 alarmvals[5];
int flags, ret;
ret = i2c_smbus_read_i2c_block_data(client, M41T80_REG_ALARM_MON,
5, alarmvals);
if (ret != 5)
return ret < 0 ? ret : -EIO;
flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
if (flags < 0)
return flags;
alrm->time.tm_sec = bcd2bin(alarmvals[4] & 0x7f);
alrm->time.tm_min = bcd2bin(alarmvals[3] & 0x7f);
alrm->time.tm_hour = bcd2bin(alarmvals[2] & 0x3f);
alrm->time.tm_mday = bcd2bin(alarmvals[1] & 0x3f);
alrm->time.tm_mon = bcd2bin(alarmvals[0] & 0x3f);
alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE);
alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled;
return 0;
}
static struct rtc_class_ops m41t80_rtc_ops = {
.read_time = m41t80_rtc_read_time,
.set_time = m41t80_rtc_set_time,
.proc = m41t80_rtc_proc,
};
#ifdef CONFIG_PM_SLEEP
static int m41t80_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
if (client->irq >= 0 && device_may_wakeup(dev))
enable_irq_wake(client->irq);
return 0;
}
static int m41t80_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
if (client->irq >= 0 && device_may_wakeup(dev))
disable_irq_wake(client->irq);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(m41t80_pm, m41t80_suspend, m41t80_resume);
static ssize_t flags_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
int val;
val = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
if (val < 0)
return val;
return sprintf(buf, "%#x\n", val);
}
static DEVICE_ATTR_RO(flags);
static struct attribute *attrs[] = {
&dev_attr_flags.attr,
NULL,
};
static struct attribute_group attr_group = {
.attrs = attrs,
};
#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,
},
};
struct m41t80_data *clientdata = i2c_get_clientdata(save_client);
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;
/*
* M41T65 has three bits for watchdog resolution. Don't set bit 7, as
* that would be an invalid resolution.
*/
if (clientdata->features & M41T80_FEATURE_WD)
i2c_data[1] &= ~M41T80_WATCHDOG_RB2;
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)
{
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 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) {
pr_info("disable watchdog\n");
wdt_disable();
}
if (rv & WDIOS_ENABLECARD) {
pr_info("enable watchdog\n");
wdt_ping();
}
return -EINVAL;
}
return -ENOTTY;
}
static long wdt_unlocked_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
int ret;
mutex_lock(&m41t80_rtc_mutex);
ret = wdt_ioctl(file, cmd, arg);
mutex_unlock(&m41t80_rtc_mutex);
return ret;
}
/**
* 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) {
mutex_lock(&m41t80_rtc_mutex);
if (test_and_set_bit(0, &wdt_is_open)) {
mutex_unlock(&m41t80_rtc_mutex);
return -EBUSY;
}
/*
* Activate
*/
wdt_is_open = 1;
mutex_unlock(&m41t80_rtc_mutex);
return nonseekable_open(inode, file);
}
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,
.unlocked_ioctl = wdt_unlocked_ioctl,
.write = wdt_write,
.open = wdt_open,
.release = wdt_release,
llseek: automatically add .llseek fop All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
2010-08-15 16:52:59 +00:00
.llseek = no_llseek,
};
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 void m41t80_remove_sysfs_group(void *_dev)
{
struct device *dev = _dev;
sysfs_remove_group(&dev->kobj, &attr_group);
}
static int m41t80_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
int rc = 0;
struct rtc_device *rtc = NULL;
struct rtc_time tm;
struct m41t80_data *m41t80_data = NULL;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK |
I2C_FUNC_SMBUS_BYTE_DATA)) {
dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n");
return -ENODEV;
}
m41t80_data = devm_kzalloc(&client->dev, sizeof(*m41t80_data),
GFP_KERNEL);
if (!m41t80_data)
return -ENOMEM;
if (client->dev.of_node)
m41t80_data->features = (unsigned long)
of_device_get_match_data(&client->dev);
else
m41t80_data->features = id->driver_data;
i2c_set_clientdata(client, m41t80_data);
if (client->irq > 0) {
rc = devm_request_threaded_irq(&client->dev, client->irq,
NULL, m41t80_handle_irq,
IRQF_TRIGGER_LOW | IRQF_ONESHOT,
"m41t80", client);
if (rc) {
dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
client->irq = 0;
} else {
m41t80_rtc_ops.read_alarm = m41t80_read_alarm;
m41t80_rtc_ops.set_alarm = m41t80_set_alarm;
m41t80_rtc_ops.alarm_irq_enable = m41t80_alarm_irq_enable;
/* Enable the wakealarm */
device_init_wakeup(&client->dev, true);
}
}
rtc = devm_rtc_device_register(&client->dev, client->name,
&m41t80_rtc_ops, THIS_MODULE);
if (IS_ERR(rtc))
return PTR_ERR(rtc);
m41t80_data->rtc = rtc;
/* Make sure HT (Halt Update) bit is cleared */
rc = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_HOUR);
if (rc >= 0 && rc & M41T80_ALHOUR_HT) {
if (m41t80_data->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);
}
rc = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_HOUR,
rc & ~M41T80_ALHOUR_HT);
}
if (rc < 0) {
dev_err(&client->dev, "Can't clear HT bit\n");
return rc;
}
/* Make sure ST (stop) bit is cleared */
rc = i2c_smbus_read_byte_data(client, M41T80_REG_SEC);
if (rc >= 0 && rc & M41T80_SEC_ST)
rc = i2c_smbus_write_byte_data(client, M41T80_REG_SEC,
rc & ~M41T80_SEC_ST);
if (rc < 0) {
dev_err(&client->dev, "Can't clear ST bit\n");
return rc;
}
/* Export sysfs entries */
rc = sysfs_create_group(&(&client->dev)->kobj, &attr_group);
if (rc) {
dev_err(&client->dev, "Failed to create sysfs group: %d\n", rc);
return rc;
}
rc = devm_add_action_or_reset(&client->dev, m41t80_remove_sysfs_group,
&client->dev);
if (rc) {
dev_err(&client->dev,
"Failed to add sysfs cleanup action: %d\n", rc);
return rc;
}
#ifdef CONFIG_RTC_DRV_M41T80_WDT
if (m41t80_data->features & M41T80_FEATURE_HT) {
save_client = client;
rc = misc_register(&wdt_dev);
if (rc)
return rc;
rc = register_reboot_notifier(&wdt_notifier);
if (rc) {
misc_deregister(&wdt_dev);
return rc;
}
}
#endif
return 0;
}
static int m41t80_remove(struct i2c_client *client)
{
#ifdef CONFIG_RTC_DRV_M41T80_WDT
struct m41t80_data *clientdata = i2c_get_clientdata(client);
if (clientdata->features & M41T80_FEATURE_HT) {
misc_deregister(&wdt_dev);
unregister_reboot_notifier(&wdt_notifier);
}
#endif
return 0;
}
static struct i2c_driver m41t80_driver = {
.driver = {
.name = "rtc-m41t80",
.of_match_table = of_match_ptr(m41t80_of_match),
.pm = &m41t80_pm,
},
.probe = m41t80_probe,
.remove = m41t80_remove,
.id_table = m41t80_id,
};
module_i2c_driver(m41t80_driver);
MODULE_AUTHOR("Alexander Bigga <ab@mycable.de>");
MODULE_DESCRIPTION("ST Microelectronics M41T80 series RTC I2C Client Driver");
MODULE_LICENSE("GPL");