linux/drivers/rtc/rtc-m41t80.c
Rob Herring 48144c2890 rtc: Explicitly include correct DT includes
The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230724205456.767430-1-robh@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2023-07-27 23:31:29 +02:00

1026 lines
26 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* 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
*/
#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.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 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 __maybe_unused 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;
unsigned long freq;
unsigned int sqwe;
#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);
unsigned long events = 0;
int flags, flags_afe;
rtc_lock(m41t80->rtc);
flags_afe = i2c_smbus_read_byte_data(client, M41T80_REG_ALARM_MON);
if (flags_afe < 0) {
rtc_unlock(m41t80->rtc);
return IRQ_NONE;
}
flags = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
if (flags <= 0) {
rtc_unlock(m41t80->rtc);
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);
}
rtc_unlock(m41t80->rtc);
return IRQ_HANDLED;
}
static int m41t80_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
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 err;
}
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 0;
}
static int m41t80_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
struct m41t80_data *clientdata = i2c_get_clientdata(client);
unsigned char buf[8];
int err, flags;
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;
err = i2c_smbus_write_byte_data(client, M41T80_REG_FLAGS,
flags & ~M41T80_FLAGS_OF);
if (err < 0) {
dev_err(&client->dev, "Unable to write flags register\n");
return err;
}
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);
int reg;
if (clientdata->features & M41T80_FEATURE_BL) {
reg = i2c_smbus_read_byte_data(client, M41T80_REG_FLAGS);
if (reg < 0)
return reg;
seq_printf(seq, "battery\t\t: %s\n",
(reg & M41T80_FLAGS_BATT_LOW) ? "exhausted" : "ok");
}
return 0;
}
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) - 1;
alrm->enabled = !!(alarmvals[0] & M41T80_ALMON_AFE);
alrm->pending = (flags & M41T80_FLAGS_AF) && alrm->enabled;
return 0;
}
static const struct rtc_class_ops m41t80_rtc_ops = {
.read_time = m41t80_rtc_read_time,
.set_time = m41t80_rtc_set_time,
.proc = m41t80_rtc_proc,
.read_alarm = m41t80_read_alarm,
.set_alarm = m41t80_set_alarm,
.alarm_irq_enable = m41t80_alarm_irq_enable,
};
#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);
#ifdef CONFIG_COMMON_CLK
#define sqw_to_m41t80_data(_hw) container_of(_hw, struct m41t80_data, sqw)
static unsigned long m41t80_decode_freq(int setting)
{
return (setting == 0) ? 0 : (setting == 1) ? M41T80_SQW_MAX_FREQ :
M41T80_SQW_MAX_FREQ >> setting;
}
static unsigned long m41t80_get_freq(struct m41t80_data *m41t80)
{
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);
if (ret < 0)
return 0;
return m41t80_decode_freq(ret >> 4);
}
static unsigned long m41t80_sqw_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
return sqw_to_m41t80_data(hw)->freq;
}
static long m41t80_sqw_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
if (rate >= M41T80_SQW_MAX_FREQ)
return M41T80_SQW_MAX_FREQ;
if (rate >= M41T80_SQW_MAX_FREQ / 4)
return M41T80_SQW_MAX_FREQ / 4;
if (!rate)
return 0;
return 1 << ilog2(rate);
}
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 >= M41T80_SQW_MAX_FREQ)
val = 1;
else if (rate >= M41T80_SQW_MAX_FREQ / 4)
val = 2;
else if (rate)
val = 15 - ilog2(rate);
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)
m41t80->freq = m41t80_decode_freq(val);
return ret;
}
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;
ret = i2c_smbus_write_byte_data(client, M41T80_REG_ALARM_MON, ret);
if (!ret)
m41t80->sqwe = enable;
return 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)
{
return sqw_to_m41t80_data(hw)->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 device_node *fixed_clock;
struct clk *clk;
struct clk_init_data init;
int ret;
fixed_clock = of_get_child_by_name(node, "clock");
if (fixed_clock) {
/*
* skip registering square wave clock when a fixed
* clock has been registered. The fixed clock is
* registered automatically when being referenced.
*/
of_node_put(fixed_clock);
return NULL;
}
/* 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;
m41t80->freq = m41t80_get_freq(m41t80);
/* 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 DEFINE_MUTEX(m41t80_rtc_mutex);
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 - write to watchdog.
* @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 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 - ioctl handler to set watchdog.
* @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();
fallthrough;
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 - open a watchdog.
* @inode: inode of device
* @file: file handle to device
*
*/
static int wdt_open(struct inode *inode, struct file *file)
{
if (iminor(inode) == 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 stream_open(inode, file);
}
return -ENODEV;
}
/**
* wdt_release - release a watchdog.
* @inode: inode to board
* @file: file handle to board
*
*/
static int wdt_release(struct inode *inode, struct file *file)
{
if (iminor(inode) == WATCHDOG_MINOR)
clear_bit(0, &wdt_is_open);
return 0;
}
/**
* wdt_notify_sys - notify to watchdog.
* @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,
.compat_ioctl = compat_ptr_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 int m41t80_probe(struct i2c_client *client)
{
struct i2c_adapter *adapter = client->adapter;
int rc = 0;
struct rtc_time tm;
struct m41t80_data *m41t80_data = NULL;
bool wakeup_source = false;
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 {
const struct i2c_device_id *id = i2c_match_id(m41t80_id, client);
m41t80_data->features = id->driver_data;
}
i2c_set_clientdata(client, m41t80_data);
m41t80_data->rtc = devm_rtc_allocate_device(&client->dev);
if (IS_ERR(m41t80_data->rtc))
return PTR_ERR(m41t80_data->rtc);
#ifdef CONFIG_OF
wakeup_source = of_property_read_bool(client->dev.of_node,
"wakeup-source");
#endif
if (client->irq > 0) {
unsigned long irqflags = IRQF_TRIGGER_LOW;
if (dev_fwnode(&client->dev))
irqflags = 0;
rc = devm_request_threaded_irq(&client->dev, client->irq,
NULL, m41t80_handle_irq,
irqflags | IRQF_ONESHOT,
"m41t80", client);
if (rc) {
dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n");
client->irq = 0;
wakeup_source = false;
}
}
if (client->irq > 0 || wakeup_source)
device_init_wakeup(&client->dev, true);
else
clear_bit(RTC_FEATURE_ALARM, m41t80_data->rtc->features);
m41t80_data->rtc->ops = &m41t80_rtc_ops;
m41t80_data->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
m41t80_data->rtc->range_max = RTC_TIMESTAMP_END_2099;
if (client->irq <= 0)
clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, m41t80_data->rtc->features);
/* 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_rtc_read_time(&client->dev, &tm);
dev_info(&client->dev, "HT bit was set!\n");
dev_info(&client->dev, "Power Down at %ptR\n", &tm);
}
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;
}
#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
rc = devm_rtc_register_device(m41t80_data->rtc);
if (rc)
return rc;
return 0;
}
static void 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
}
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");