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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/clk-provider.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_SQW_MAX_FREQ 32768
#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 i2c_client *client;
struct rtc_device *rtc;
#ifdef CONFIG_COMMON_CLK
struct clk_hw sqw;
#endif
};
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_COMMON_CLK
#define sqw_to_m41t80_data(_hw) container_of(_hw, struct m41t80_data, sqw)
static unsigned long m41t80_sqw_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
struct i2c_client *client = m41t80->client;
int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ?
M41T80_REG_WDAY : M41T80_REG_SQW;
int ret = i2c_smbus_read_byte_data(client, reg_sqw);
unsigned long val = M41T80_SQW_MAX_FREQ;
if (ret < 0)
return 0;
ret >>= 4;
if (ret == 0)
val = 0;
else if (ret > 1)
val = val / (1 << ret);
return val;
}
static long m41t80_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
int i, freq = M41T80_SQW_MAX_FREQ;
if (freq <= rate)
return freq;
for (i = 2; i <= ilog2(M41T80_SQW_MAX_FREQ); i++) {
freq /= 1 << i;
if (freq <= rate)
return freq;
}
return 0;
}
static int m41t80_sqw_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
struct i2c_client *client = m41t80->client;
int reg_sqw = (m41t80->features & M41T80_FEATURE_SQ_ALT) ?
M41T80_REG_WDAY : M41T80_REG_SQW;
int reg, ret, val = 0;
if (rate) {
if (!is_power_of_2(rate))
return -EINVAL;
val = ilog2(rate);
if (val == ilog2(M41T80_SQW_MAX_FREQ))
val = 1;
else if (val < (ilog2(M41T80_SQW_MAX_FREQ) - 1))
val = ilog2(M41T80_SQW_MAX_FREQ) - val;
else
return -EINVAL;
}
reg = i2c_smbus_read_byte_data(client, reg_sqw);
if (reg < 0)
return reg;
reg = (reg & 0x0f) | (val << 4);
ret = i2c_smbus_write_byte_data(client, reg_sqw, reg);
if (ret < 0)
return ret;
return -EINVAL;
}
static int m41t80_sqw_control(struct clk_hw *hw, bool enable)
{
struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
struct i2c_client *client = m41t80->client;
int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
if (ret < 0)
return ret;
if (enable)
ret |= M41T80_ALMON_SQWE;
else
ret &= ~M41T80_ALMON_SQWE;
return i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret);
}
static int m41t80_sqw_prepare(struct clk_hw *hw)
{
return m41t80_sqw_control(hw, 1);
}
static void m41t80_sqw_unprepare(struct clk_hw *hw)
{
m41t80_sqw_control(hw, 0);
}
static int m41t80_sqw_is_prepared(struct clk_hw *hw)
{
struct m41t80_data *m41t80 = sqw_to_m41t80_data(hw);
struct i2c_client *client = m41t80->client;
int ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
if (ret < 0)
return ret;
return !!(ret & M41T80_ALMON_SQWE);
}
static const struct clk_ops m41t80_sqw_ops = {
.prepare = m41t80_sqw_prepare,
.unprepare = m41t80_sqw_unprepare,
.is_prepared = m41t80_sqw_is_prepared,
.recalc_rate = m41t80_sqw_recalc_rate,
.round_rate = m41t80_sqw_round_rate,
.set_rate = m41t80_sqw_set_rate,
};
static struct clk *m41t80_sqw_register_clk(struct m41t80_data *m41t80)
{
struct i2c_client *client = m41t80->client;
struct device_node *node = client->dev.of_node;
struct clk *clk;
struct clk_init_data init;
int ret;
/* First disable the clock */
ret = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
if (ret < 0)
return ERR_PTR(ret);
ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON,
ret & ~(M41T80_ALMON_SQWE));
if (ret < 0)
return ERR_PTR(ret);
init.name = "m41t80-sqw";
init.ops = &m41t80_sqw_ops;
init.flags = 0;
init.parent_names = NULL;
init.num_parents = 0;
m41t80->sqw.init = &init;
/* optional override of the clockname */
of_property_read_string(node, "clock-output-names", &init.name);
/* register the clock */
clk = clk_register(&client->dev, &m41t80->sqw);
if (!IS_ERR(clk))
of_clk_add_provider(node, of_clk_src_simple_get, clk);
return clk;
}
#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,
},
};
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 = 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;
m41t80_data->client = client;
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
#ifdef CONFIG_COMMON_CLK
if (m41t80_data->features & M41T80_FEATURE_SQ)
m41t80_sqw_register_clk(m41t80_data);
#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");
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