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linux/drivers/rtc/rtc-ds1307.c
Nishanth Menon e3edd67141 rtc: ds1307: Enable the mcp794xx alarm after programming time 
Alarm interrupt enable register is at offset 0x7, while the time
registers for the alarm follow that. When we program Alarm interrupt
enable prior to programming the time, it is possible that previous
time value could be close or match at the time of alarm enable
resulting in interrupt trigger which is unexpected (and does not match
the time we expect it to trigger).

To prevent this scenario from occuring, program the ALM0_EN bit only
after the alarm time is appropriately programmed.

Ofcourse, I2C programming is non-atomic, so there are loopholes where
the interrupt wont trigger if the time requested is in the past at
the time of programming the ALM0_EN bit. However, we will not have
unexpected interrupts while the time is programmed after the interrupt
are enabled.

Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2015-06-25 01:13:46 +02:00

1259 lines
33 KiB
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Raw Blame History

/*
* rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.
*
* Copyright (C) 2005 James Chapman (ds1337 core)
* Copyright (C) 2006 David Brownell
* Copyright (C) 2009 Matthias Fuchs (rx8025 support)
* Copyright (C) 2012 Bertrand Achard (nvram access fixes)
*
* 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.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/string.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <linux/rtc/ds1307.h>
/*
* We can't determine type by probing, but if we expect pre-Linux code
* to have set the chip up as a clock (turning on the oscillator and
* setting the date and time), Linux can ignore the non-clock features.
* That's a natural job for a factory or repair bench.
*/
enum ds_type {
ds_1307,
ds_1337,
ds_1338,
ds_1339,
ds_1340,
ds_1388,
ds_3231,
m41t00,
mcp794xx,
rx_8025,
last_ds_type /* always last */
/* rs5c372 too? different address... */
};
/* RTC registers don't differ much, except for the century flag */
#define DS1307_REG_SECS 0x00 /* 00-59 */
# define DS1307_BIT_CH 0x80
# define DS1340_BIT_nEOSC 0x80
# define MCP794XX_BIT_ST 0x80
#define DS1307_REG_MIN 0x01 /* 00-59 */
#define DS1307_REG_HOUR 0x02 /* 00-23, or 1-12{am,pm} */
# define DS1307_BIT_12HR 0x40 /* in REG_HOUR */
# define DS1307_BIT_PM 0x20 /* in REG_HOUR */
# define DS1340_BIT_CENTURY_EN 0x80 /* in REG_HOUR */
# define DS1340_BIT_CENTURY 0x40 /* in REG_HOUR */
#define DS1307_REG_WDAY 0x03 /* 01-07 */
# define MCP794XX_BIT_VBATEN 0x08
#define DS1307_REG_MDAY 0x04 /* 01-31 */
#define DS1307_REG_MONTH 0x05 /* 01-12 */
# define DS1337_BIT_CENTURY 0x80 /* in REG_MONTH */
#define DS1307_REG_YEAR 0x06 /* 00-99 */
/*
* Other registers (control, status, alarms, trickle charge, NVRAM, etc)
* start at 7, and they differ a LOT. Only control and status matter for
* basic RTC date and time functionality; be careful using them.
*/
#define DS1307_REG_CONTROL 0x07 /* or ds1338 */
# define DS1307_BIT_OUT 0x80
# define DS1338_BIT_OSF 0x20
# define DS1307_BIT_SQWE 0x10
# define DS1307_BIT_RS1 0x02
# define DS1307_BIT_RS0 0x01
#define DS1337_REG_CONTROL 0x0e
# define DS1337_BIT_nEOSC 0x80
# define DS1339_BIT_BBSQI 0x20
# define DS3231_BIT_BBSQW 0x40 /* same as BBSQI */
# define DS1337_BIT_RS2 0x10
# define DS1337_BIT_RS1 0x08
# define DS1337_BIT_INTCN 0x04
# define DS1337_BIT_A2IE 0x02
# define DS1337_BIT_A1IE 0x01
#define DS1340_REG_CONTROL 0x07
# define DS1340_BIT_OUT 0x80
# define DS1340_BIT_FT 0x40
# define DS1340_BIT_CALIB_SIGN 0x20
# define DS1340_M_CALIBRATION 0x1f
#define DS1340_REG_FLAG 0x09
# define DS1340_BIT_OSF 0x80
#define DS1337_REG_STATUS 0x0f
# define DS1337_BIT_OSF 0x80
# define DS1337_BIT_A2I 0x02
# define DS1337_BIT_A1I 0x01
#define DS1339_REG_ALARM1_SECS 0x07
#define DS13XX_TRICKLE_CHARGER_MAGIC 0xa0
#define RX8025_REG_CTRL1 0x0e
# define RX8025_BIT_2412 0x20
#define RX8025_REG_CTRL2 0x0f
# define RX8025_BIT_PON 0x10
# define RX8025_BIT_VDET 0x40
# define RX8025_BIT_XST 0x20
struct ds1307 {
u8 offset; /* register's offset */
u8 regs[11];
u16 nvram_offset;
struct bin_attribute *nvram;
enum ds_type type;
unsigned long flags;
#define HAS_NVRAM 0 /* bit 0 == sysfs file active */
#define HAS_ALARM 1 /* bit 1 == irq claimed */
struct i2c_client *client;
struct rtc_device *rtc;
struct work_struct work;
s32 (*read_block_data)(const struct i2c_client *client, u8 command,
u8 length, u8 *values);
s32 (*write_block_data)(const struct i2c_client *client, u8 command,
u8 length, const u8 *values);
};
struct chip_desc {
unsigned alarm:1;
u16 nvram_offset;
u16 nvram_size;
u16 trickle_charger_reg;
u8 trickle_charger_setup;
u8 (*do_trickle_setup)(struct i2c_client *, uint32_t, bool);
};
static u8 do_trickle_setup_ds1339(struct i2c_client *,
uint32_t ohms, bool diode);
static struct chip_desc chips[last_ds_type] = {
[ds_1307] = {
.nvram_offset = 8,
.nvram_size = 56,
},
[ds_1337] = {
.alarm = 1,
},
[ds_1338] = {
.nvram_offset = 8,
.nvram_size = 56,
},
[ds_1339] = {
.alarm = 1,
.trickle_charger_reg = 0x10,
.do_trickle_setup = &do_trickle_setup_ds1339,
},
[ds_1340] = {
.trickle_charger_reg = 0x08,
},
[ds_1388] = {
.trickle_charger_reg = 0x0a,
},
[ds_3231] = {
.alarm = 1,
},
[mcp794xx] = {
.alarm = 1,
/* this is battery backed SRAM */
.nvram_offset = 0x20,
.nvram_size = 0x40,
},
};
static const struct i2c_device_id ds1307_id[] = {
{ "ds1307", ds_1307 },
{ "ds1337", ds_1337 },
{ "ds1338", ds_1338 },
{ "ds1339", ds_1339 },
{ "ds1388", ds_1388 },
{ "ds1340", ds_1340 },
{ "ds3231", ds_3231 },
{ "m41t00", m41t00 },
{ "mcp7940x", mcp794xx },
{ "mcp7941x", mcp794xx },
{ "pt7c4338", ds_1307 },
{ "rx8025", rx_8025 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ds1307_id);
/*----------------------------------------------------------------------*/
#define BLOCK_DATA_MAX_TRIES 10
static s32 ds1307_read_block_data_once(const struct i2c_client *client,
u8 command, u8 length, u8 *values)
{
s32 i, data;
for (i = 0; i < length; i++) {
data = i2c_smbus_read_byte_data(client, command + i);
if (data < 0)
return data;
values[i] = data;
}
return i;
}
static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
u8 length, u8 *values)
{
u8 oldvalues[255];
s32 ret;
int tries = 0;
dev_dbg(&client->dev, "ds1307_read_block_data (length=%d)\n", length);
ret = ds1307_read_block_data_once(client, command, length, values);
if (ret < 0)
return ret;
do {
if (++tries > BLOCK_DATA_MAX_TRIES) {
dev_err(&client->dev,
"ds1307_read_block_data failed\n");
return -EIO;
}
memcpy(oldvalues, values, length);
ret = ds1307_read_block_data_once(client, command, length,
values);
if (ret < 0)
return ret;
} while (memcmp(oldvalues, values, length));
return length;
}
static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
u8 length, const u8 *values)
{
u8 currvalues[255];
int tries = 0;
dev_dbg(&client->dev, "ds1307_write_block_data (length=%d)\n", length);
do {
s32 i, ret;
if (++tries > BLOCK_DATA_MAX_TRIES) {
dev_err(&client->dev,
"ds1307_write_block_data failed\n");
return -EIO;
}
for (i = 0; i < length; i++) {
ret = i2c_smbus_write_byte_data(client, command + i,
values[i]);
if (ret < 0)
return ret;
}
ret = ds1307_read_block_data_once(client, command, length,
currvalues);
if (ret < 0)
return ret;
} while (memcmp(currvalues, values, length));
return length;
}
/*----------------------------------------------------------------------*/
/* These RTC devices are not designed to be connected to a SMbus adapter.
SMbus limits block operations length to 32 bytes, whereas it's not
limited on I2C buses. As a result, accesses may exceed 32 bytes;
in that case, split them into smaller blocks */
static s32 ds1307_native_smbus_write_block_data(const struct i2c_client *client,
u8 command, u8 length, const u8 *values)
{
u8 suboffset = 0;
if (length <= I2C_SMBUS_BLOCK_MAX)
return i2c_smbus_write_i2c_block_data(client,
command, length, values);
while (suboffset < length) {
s32 retval = i2c_smbus_write_i2c_block_data(client,
command + suboffset,
min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
values + suboffset);
if (retval < 0)
return retval;
suboffset += I2C_SMBUS_BLOCK_MAX;
}
return length;
}
static s32 ds1307_native_smbus_read_block_data(const struct i2c_client *client,
u8 command, u8 length, u8 *values)
{
u8 suboffset = 0;
if (length <= I2C_SMBUS_BLOCK_MAX)
return i2c_smbus_read_i2c_block_data(client,
command, length, values);
while (suboffset < length) {
s32 retval = i2c_smbus_read_i2c_block_data(client,
command + suboffset,
min(I2C_SMBUS_BLOCK_MAX, length - suboffset),
values + suboffset);
if (retval < 0)
return retval;
suboffset += I2C_SMBUS_BLOCK_MAX;
}
return length;
}
/*----------------------------------------------------------------------*/
/*
* The IRQ logic includes a "real" handler running in IRQ context just
* long enough to schedule this workqueue entry. We need a task context
* to talk to the RTC, since I2C I/O calls require that; and disable the
* IRQ until we clear its status on the chip, so that this handler can
* work with any type of triggering (not just falling edge).
*
* The ds1337 and ds1339 both have two alarms, but we only use the first
* one (with a "seconds" field). For ds1337 we expect nINTA is our alarm
* signal; ds1339 chips have only one alarm signal.
*/
static void ds1307_work(struct work_struct *work)
{
struct ds1307 *ds1307;
struct i2c_client *client;
struct mutex *lock;
int stat, control;
ds1307 = container_of(work, struct ds1307, work);
client = ds1307->client;
lock = &ds1307->rtc->ops_lock;
mutex_lock(lock);
stat = i2c_smbus_read_byte_data(client, DS1337_REG_STATUS);
if (stat < 0)
goto out;
if (stat & DS1337_BIT_A1I) {
stat &= ~DS1337_BIT_A1I;
i2c_smbus_write_byte_data(client, DS1337_REG_STATUS, stat);
control = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
if (control < 0)
goto out;
control &= ~DS1337_BIT_A1IE;
i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, control);
rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
}
out:
if (test_bit(HAS_ALARM, &ds1307->flags))
enable_irq(client->irq);
mutex_unlock(lock);
}
static irqreturn_t ds1307_irq(int irq, void *dev_id)
{
struct i2c_client *client = dev_id;
struct ds1307 *ds1307 = i2c_get_clientdata(client);
disable_irq_nosync(irq);
schedule_work(&ds1307->work);
return IRQ_HANDLED;
}
/*----------------------------------------------------------------------*/
static int ds1307_get_time(struct device *dev, struct rtc_time *t)
{
struct ds1307 *ds1307 = dev_get_drvdata(dev);
int tmp;
/* read the RTC date and time registers all at once */
tmp = ds1307->read_block_data(ds1307->client,
ds1307->offset, 7, ds1307->regs);
if (tmp != 7) {
dev_err(dev, "%s error %d\n", "read", tmp);
return -EIO;
}
dev_dbg(dev, "%s: %7ph\n", "read", ds1307->regs);
t->tm_sec = bcd2bin(ds1307->regs[DS1307_REG_SECS] & 0x7f);
t->tm_min = bcd2bin(ds1307->regs[DS1307_REG_MIN] & 0x7f);
tmp = ds1307->regs[DS1307_REG_HOUR] & 0x3f;
t->tm_hour = bcd2bin(tmp);
t->tm_wday = bcd2bin(ds1307->regs[DS1307_REG_WDAY] & 0x07) - 1;
t->tm_mday = bcd2bin(ds1307->regs[DS1307_REG_MDAY] & 0x3f);
tmp = ds1307->regs[DS1307_REG_MONTH] & 0x1f;
t->tm_mon = bcd2bin(tmp) - 1;
/* assume 20YY not 19YY, and ignore DS1337_BIT_CENTURY */
t->tm_year = bcd2bin(ds1307->regs[DS1307_REG_YEAR]) + 100;
dev_dbg(dev, "%s secs=%d, mins=%d, "
"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
"read", t->tm_sec, t->tm_min,
t->tm_hour, t->tm_mday,
t->tm_mon, t->tm_year, t->tm_wday);
/* initial clock setting can be undefined */
return rtc_valid_tm(t);
}
static int ds1307_set_time(struct device *dev, struct rtc_time *t)
{
struct ds1307 *ds1307 = dev_get_drvdata(dev);
int result;
int tmp;
u8 *buf = ds1307->regs;
dev_dbg(dev, "%s secs=%d, mins=%d, "
"hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
"write", t->tm_sec, t->tm_min,
t->tm_hour, t->tm_mday,
t->tm_mon, t->tm_year, t->tm_wday);
buf[DS1307_REG_SECS] = bin2bcd(t->tm_sec);
buf[DS1307_REG_MIN] = bin2bcd(t->tm_min);
buf[DS1307_REG_HOUR] = bin2bcd(t->tm_hour);
buf[DS1307_REG_WDAY] = bin2bcd(t->tm_wday + 1);
buf[DS1307_REG_MDAY] = bin2bcd(t->tm_mday);
buf[DS1307_REG_MONTH] = bin2bcd(t->tm_mon + 1);
/* assume 20YY not 19YY */
tmp = t->tm_year - 100;
buf[DS1307_REG_YEAR] = bin2bcd(tmp);
switch (ds1307->type) {
case ds_1337:
case ds_1339:
case ds_3231:
buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;
break;
case ds_1340:
buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN
| DS1340_BIT_CENTURY;
break;
case mcp794xx:
/*
* these bits were cleared when preparing the date/time
* values and need to be set again before writing the
* buffer out to the device.
*/
buf[DS1307_REG_SECS] |= MCP794XX_BIT_ST;
buf[DS1307_REG_WDAY] |= MCP794XX_BIT_VBATEN;
break;
default:
break;
}
dev_dbg(dev, "%s: %7ph\n", "write", buf);
result = ds1307->write_block_data(ds1307->client,
ds1307->offset, 7, buf);
if (result < 0) {
dev_err(dev, "%s error %d\n", "write", result);
return result;
}
return 0;
}
static int ds1337_read_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1307 *ds1307 = i2c_get_clientdata(client);
int ret;
if (!test_bit(HAS_ALARM, &ds1307->flags))
return -EINVAL;
/* read all ALARM1, ALARM2, and status registers at once */
ret = ds1307->read_block_data(client,
DS1339_REG_ALARM1_SECS, 9, ds1307->regs);
if (ret != 9) {
dev_err(dev, "%s error %d\n", "alarm read", ret);
return -EIO;
}
dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
"alarm read",
ds1307->regs[0], ds1307->regs[1],
ds1307->regs[2], ds1307->regs[3],
ds1307->regs[4], ds1307->regs[5],
ds1307->regs[6], ds1307->regs[7],
ds1307->regs[8]);
/*
* report alarm time (ALARM1); assume 24 hour and day-of-month modes,
* and that all four fields are checked matches
*/
t->time.tm_sec = bcd2bin(ds1307->regs[0] & 0x7f);
t->time.tm_min = bcd2bin(ds1307->regs[1] & 0x7f);
t->time.tm_hour = bcd2bin(ds1307->regs[2] & 0x3f);
t->time.tm_mday = bcd2bin(ds1307->regs[3] & 0x3f);
t->time.tm_mon = -1;
t->time.tm_year = -1;
t->time.tm_wday = -1;
t->time.tm_yday = -1;
t->time.tm_isdst = -1;
/* ... and status */
t->enabled = !!(ds1307->regs[7] & DS1337_BIT_A1IE);
t->pending = !!(ds1307->regs[8] & DS1337_BIT_A1I);
dev_dbg(dev, "%s secs=%d, mins=%d, "
"hours=%d, mday=%d, enabled=%d, pending=%d\n",
"alarm read", t->time.tm_sec, t->time.tm_min,
t->time.tm_hour, t->time.tm_mday,
t->enabled, t->pending);
return 0;
}
static int ds1337_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1307 *ds1307 = i2c_get_clientdata(client);
unsigned char *buf = ds1307->regs;
u8 control, status;
int ret;
if (!test_bit(HAS_ALARM, &ds1307->flags))
return -EINVAL;
dev_dbg(dev, "%s secs=%d, mins=%d, "
"hours=%d, mday=%d, enabled=%d, pending=%d\n",
"alarm set", t->time.tm_sec, t->time.tm_min,
t->time.tm_hour, t->time.tm_mday,
t->enabled, t->pending);
/* read current status of both alarms and the chip */
ret = ds1307->read_block_data(client,
DS1339_REG_ALARM1_SECS, 9, buf);
if (ret != 9) {
dev_err(dev, "%s error %d\n", "alarm write", ret);
return -EIO;
}
control = ds1307->regs[7];
status = ds1307->regs[8];
dev_dbg(dev, "%s: %02x %02x %02x %02x, %02x %02x %02x, %02x %02x\n",
"alarm set (old status)",
ds1307->regs[0], ds1307->regs[1],
ds1307->regs[2], ds1307->regs[3],
ds1307->regs[4], ds1307->regs[5],
ds1307->regs[6], control, status);
/* set ALARM1, using 24 hour and day-of-month modes */
buf[0] = bin2bcd(t->time.tm_sec);
buf[1] = bin2bcd(t->time.tm_min);
buf[2] = bin2bcd(t->time.tm_hour);
buf[3] = bin2bcd(t->time.tm_mday);
/* set ALARM2 to non-garbage */
buf[4] = 0;
buf[5] = 0;
buf[6] = 0;
/* optionally enable ALARM1 */
buf[7] = control & ~(DS1337_BIT_A1IE | DS1337_BIT_A2IE);
if (t->enabled) {
dev_dbg(dev, "alarm IRQ armed\n");
buf[7] |= DS1337_BIT_A1IE; /* only ALARM1 is used */
}
buf[8] = status & ~(DS1337_BIT_A1I | DS1337_BIT_A2I);
ret = ds1307->write_block_data(client,
DS1339_REG_ALARM1_SECS, 9, buf);
if (ret < 0) {
dev_err(dev, "can't set alarm time\n");
return ret;
}
return 0;
}
static int ds1307_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1307 *ds1307 = i2c_get_clientdata(client);
int ret;
if (!test_bit(HAS_ALARM, &ds1307->flags))
return -ENOTTY;
ret = i2c_smbus_read_byte_data(client, DS1337_REG_CONTROL);
if (ret < 0)
return ret;
if (enabled)
ret |= DS1337_BIT_A1IE;
else
ret &= ~DS1337_BIT_A1IE;
ret = i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL, ret);
if (ret < 0)
return ret;
return 0;
}
static const struct rtc_class_ops ds13xx_rtc_ops = {
.read_time = ds1307_get_time,
.set_time = ds1307_set_time,
.read_alarm = ds1337_read_alarm,
.set_alarm = ds1337_set_alarm,
.alarm_irq_enable = ds1307_alarm_irq_enable,
};
/*----------------------------------------------------------------------*/
/*
* Alarm support for mcp794xx devices.
*/
#define MCP794XX_REG_CONTROL 0x07
# define MCP794XX_BIT_ALM0_EN 0x10
# define MCP794XX_BIT_ALM1_EN 0x20
#define MCP794XX_REG_ALARM0_BASE 0x0a
#define MCP794XX_REG_ALARM0_CTRL 0x0d
#define MCP794XX_REG_ALARM1_BASE 0x11
#define MCP794XX_REG_ALARM1_CTRL 0x14
# define MCP794XX_BIT_ALMX_IF (1 << 3)
# define MCP794XX_BIT_ALMX_C0 (1 << 4)
# define MCP794XX_BIT_ALMX_C1 (1 << 5)
# define MCP794XX_BIT_ALMX_C2 (1 << 6)
# define MCP794XX_BIT_ALMX_POL (1 << 7)
# define MCP794XX_MSK_ALMX_MATCH (MCP794XX_BIT_ALMX_C0 | \
MCP794XX_BIT_ALMX_C1 | \
MCP794XX_BIT_ALMX_C2)
static void mcp794xx_work(struct work_struct *work)
{
struct ds1307 *ds1307 = container_of(work, struct ds1307, work);
struct i2c_client *client = ds1307->client;
int reg, ret;
mutex_lock(&ds1307->rtc->ops_lock);
/* Check and clear alarm 0 interrupt flag. */
reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_ALARM0_CTRL);
if (reg < 0)
goto out;
if (!(reg & MCP794XX_BIT_ALMX_IF))
goto out;
reg &= ~MCP794XX_BIT_ALMX_IF;
ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_ALARM0_CTRL, reg);
if (ret < 0)
goto out;
/* Disable alarm 0. */
reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
if (reg < 0)
goto out;
reg &= ~MCP794XX_BIT_ALM0_EN;
ret = i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
if (ret < 0)
goto out;
rtc_update_irq(ds1307->rtc, 1, RTC_AF | RTC_IRQF);
out:
if (test_bit(HAS_ALARM, &ds1307->flags))
enable_irq(client->irq);
mutex_unlock(&ds1307->rtc->ops_lock);
}
static int mcp794xx_read_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1307 *ds1307 = i2c_get_clientdata(client);
u8 *regs = ds1307->regs;
int ret;
if (!test_bit(HAS_ALARM, &ds1307->flags))
return -EINVAL;
/* Read control and alarm 0 registers. */
ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
if (ret < 0)
return ret;
t->enabled = !!(regs[0] & MCP794XX_BIT_ALM0_EN);
/* Report alarm 0 time assuming 24-hour and day-of-month modes. */
t->time.tm_sec = bcd2bin(ds1307->regs[3] & 0x7f);
t->time.tm_min = bcd2bin(ds1307->regs[4] & 0x7f);
t->time.tm_hour = bcd2bin(ds1307->regs[5] & 0x3f);
t->time.tm_wday = bcd2bin(ds1307->regs[6] & 0x7) - 1;
t->time.tm_mday = bcd2bin(ds1307->regs[7] & 0x3f);
t->time.tm_mon = bcd2bin(ds1307->regs[8] & 0x1f) - 1;
t->time.tm_year = -1;
t->time.tm_yday = -1;
t->time.tm_isdst = -1;
dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
"enabled=%d polarity=%d irq=%d match=%d\n", __func__,
t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
t->time.tm_wday, t->time.tm_mday, t->time.tm_mon, t->enabled,
!!(ds1307->regs[6] & MCP794XX_BIT_ALMX_POL),
!!(ds1307->regs[6] & MCP794XX_BIT_ALMX_IF),
(ds1307->regs[6] & MCP794XX_MSK_ALMX_MATCH) >> 4);
return 0;
}
static int mcp794xx_set_alarm(struct device *dev, struct rtc_wkalrm *t)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1307 *ds1307 = i2c_get_clientdata(client);
unsigned char *regs = ds1307->regs;
int ret;
if (!test_bit(HAS_ALARM, &ds1307->flags))
return -EINVAL;
dev_dbg(dev, "%s, sec=%d min=%d hour=%d wday=%d mday=%d mon=%d "
"enabled=%d pending=%d\n", __func__,
t->time.tm_sec, t->time.tm_min, t->time.tm_hour,
t->time.tm_wday, t->time.tm_mday, t->time.tm_mon,
t->enabled, t->pending);
/* Read control and alarm 0 registers. */
ret = ds1307->read_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
if (ret < 0)
return ret;
/* Set alarm 0, using 24-hour and day-of-month modes. */
regs[3] = bin2bcd(t->time.tm_sec);
regs[4] = bin2bcd(t->time.tm_min);
regs[5] = bin2bcd(t->time.tm_hour);
regs[6] = bin2bcd(t->time.tm_wday) + 1;
regs[7] = bin2bcd(t->time.tm_mday);
regs[8] = bin2bcd(t->time.tm_mon) + 1;
/* Clear the alarm 0 interrupt flag. */
regs[6] &= ~MCP794XX_BIT_ALMX_IF;
/* Set alarm match: second, minute, hour, day, date, month. */
regs[6] |= MCP794XX_MSK_ALMX_MATCH;
/* Disable interrupt. We will not enable until completely programmed */
regs[0] &= ~MCP794XX_BIT_ALM0_EN;
ret = ds1307->write_block_data(client, MCP794XX_REG_CONTROL, 10, regs);
if (ret < 0)
return ret;
if (!t->enabled)
return 0;
regs[0] |= MCP794XX_BIT_ALM0_EN;
return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, regs[0]);
}
static int mcp794xx_alarm_irq_enable(struct device *dev, unsigned int enabled)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds1307 *ds1307 = i2c_get_clientdata(client);
int reg;
if (!test_bit(HAS_ALARM, &ds1307->flags))
return -EINVAL;
reg = i2c_smbus_read_byte_data(client, MCP794XX_REG_CONTROL);
if (reg < 0)
return reg;
if (enabled)
reg |= MCP794XX_BIT_ALM0_EN;
else
reg &= ~MCP794XX_BIT_ALM0_EN;
return i2c_smbus_write_byte_data(client, MCP794XX_REG_CONTROL, reg);
}
static const struct rtc_class_ops mcp794xx_rtc_ops = {
.read_time = ds1307_get_time,
.set_time = ds1307_set_time,
.read_alarm = mcp794xx_read_alarm,
.set_alarm = mcp794xx_set_alarm,
.alarm_irq_enable = mcp794xx_alarm_irq_enable,
};
/*----------------------------------------------------------------------*/
static ssize_t
ds1307_nvram_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client;
struct ds1307 *ds1307;
int result;
client = kobj_to_i2c_client(kobj);
ds1307 = i2c_get_clientdata(client);
if (unlikely(off >= ds1307->nvram->size))
return 0;
if ((off + count) > ds1307->nvram->size)
count = ds1307->nvram->size - off;
if (unlikely(!count))
return count;
result = ds1307->read_block_data(client, ds1307->nvram_offset + off,
count, buf);
if (result < 0)
dev_err(&client->dev, "%s error %d\n", "nvram read", result);
return result;
}
static ssize_t
ds1307_nvram_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *attr,
char *buf, loff_t off, size_t count)
{
struct i2c_client *client;
struct ds1307 *ds1307;
int result;
client = kobj_to_i2c_client(kobj);
ds1307 = i2c_get_clientdata(client);
if (unlikely(off >= ds1307->nvram->size))
return -EFBIG;
if ((off + count) > ds1307->nvram->size)
count = ds1307->nvram->size - off;
if (unlikely(!count))
return count;
result = ds1307->write_block_data(client, ds1307->nvram_offset + off,
count, buf);
if (result < 0) {
dev_err(&client->dev, "%s error %d\n", "nvram write", result);
return result;
}
return count;
}
/*----------------------------------------------------------------------*/
static u8 do_trickle_setup_ds1339(struct i2c_client *client,
uint32_t ohms, bool diode)
{
u8 setup = (diode) ? DS1307_TRICKLE_CHARGER_DIODE :
DS1307_TRICKLE_CHARGER_NO_DIODE;
switch (ohms) {
case 250:
setup |= DS1307_TRICKLE_CHARGER_250_OHM;
break;
case 2000:
setup |= DS1307_TRICKLE_CHARGER_2K_OHM;
break;
case 4000:
setup |= DS1307_TRICKLE_CHARGER_4K_OHM;
break;
default:
dev_warn(&client->dev,
"Unsupported ohm value %u in dt\n", ohms);
return 0;
}
return setup;
}
static void ds1307_trickle_of_init(struct i2c_client *client,
struct chip_desc *chip)
{
uint32_t ohms = 0;
bool diode = true;
if (!chip->do_trickle_setup)
goto out;
if (of_property_read_u32(client->dev.of_node, "trickle-resistor-ohms" , &ohms))
goto out;
if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable"))
diode = false;
chip->trickle_charger_setup = chip->do_trickle_setup(client,
ohms, diode);
out:
return;
}
static int ds1307_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds1307 *ds1307;
int err = -ENODEV;
int tmp;
struct chip_desc *chip = &chips[id->driver_data];
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
bool want_irq = false;
unsigned char *buf;
struct ds1307_platform_data *pdata = dev_get_platdata(&client->dev);
static const int bbsqi_bitpos[] = {
[ds_1337] = 0,
[ds_1339] = DS1339_BIT_BBSQI,
[ds_3231] = DS3231_BIT_BBSQW,
};
const struct rtc_class_ops *rtc_ops = &ds13xx_rtc_ops;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)
&& !i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
return -EIO;
ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
if (!ds1307)
return -ENOMEM;
i2c_set_clientdata(client, ds1307);
ds1307->client = client;
ds1307->type = id->driver_data;
if (!pdata && client->dev.of_node)
ds1307_trickle_of_init(client, chip);
else if (pdata && pdata->trickle_charger_setup)
chip->trickle_charger_setup = pdata->trickle_charger_setup;
if (chip->trickle_charger_setup && chip->trickle_charger_reg) {
dev_dbg(&client->dev, "writing trickle charger info 0x%x to 0x%x\n",
DS13XX_TRICKLE_CHARGER_MAGIC | chip->trickle_charger_setup,
chip->trickle_charger_reg);
i2c_smbus_write_byte_data(client, chip->trickle_charger_reg,
DS13XX_TRICKLE_CHARGER_MAGIC |
chip->trickle_charger_setup);
}
buf = ds1307->regs;
if (i2c_check_functionality(adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
ds1307->read_block_data = ds1307_native_smbus_read_block_data;
ds1307->write_block_data = ds1307_native_smbus_write_block_data;
} else {
ds1307->read_block_data = ds1307_read_block_data;
ds1307->write_block_data = ds1307_write_block_data;
}
switch (ds1307->type) {
case ds_1337:
case ds_1339:
case ds_3231:
/* get registers that the "rtc" read below won't read... */
tmp = ds1307->read_block_data(ds1307->client,
DS1337_REG_CONTROL, 2, buf);
if (tmp != 2) {
dev_dbg(&client->dev, "read error %d\n", tmp);
err = -EIO;
goto exit;
}
/* oscillator off? turn it on, so clock can tick. */
if (ds1307->regs[0] & DS1337_BIT_nEOSC)
ds1307->regs[0] &= ~DS1337_BIT_nEOSC;
/*
* Using IRQ? Disable the square wave and both alarms.
* For some variants, be sure alarms can trigger when we're
* running on Vbackup (BBSQI/BBSQW)
*/
if (ds1307->client->irq > 0 && chip->alarm) {
INIT_WORK(&ds1307->work, ds1307_work);
ds1307->regs[0] |= DS1337_BIT_INTCN
| bbsqi_bitpos[ds1307->type];
ds1307->regs[0] &= ~(DS1337_BIT_A2IE | DS1337_BIT_A1IE);
want_irq = true;
}
i2c_smbus_write_byte_data(client, DS1337_REG_CONTROL,
ds1307->regs[0]);
/* oscillator fault? clear flag, and warn */
if (ds1307->regs[1] & DS1337_BIT_OSF) {
i2c_smbus_write_byte_data(client, DS1337_REG_STATUS,
ds1307->regs[1] & ~DS1337_BIT_OSF);
dev_warn(&client->dev, "SET TIME!\n");
}
break;
case rx_8025:
tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
if (tmp != 2) {
dev_dbg(&client->dev, "read error %d\n", tmp);
err = -EIO;
goto exit;
}
/* oscillator off? turn it on, so clock can tick. */
if (!(ds1307->regs[1] & RX8025_BIT_XST)) {
ds1307->regs[1] |= RX8025_BIT_XST;
i2c_smbus_write_byte_data(client,
RX8025_REG_CTRL2 << 4 | 0x08,
ds1307->regs[1]);
dev_warn(&client->dev,
"oscillator stop detected - SET TIME!\n");
}
if (ds1307->regs[1] & RX8025_BIT_PON) {
ds1307->regs[1] &= ~RX8025_BIT_PON;
i2c_smbus_write_byte_data(client,
RX8025_REG_CTRL2 << 4 | 0x08,
ds1307->regs[1]);
dev_warn(&client->dev, "power-on detected\n");
}
if (ds1307->regs[1] & RX8025_BIT_VDET) {
ds1307->regs[1] &= ~RX8025_BIT_VDET;
i2c_smbus_write_byte_data(client,
RX8025_REG_CTRL2 << 4 | 0x08,
ds1307->regs[1]);
dev_warn(&client->dev, "voltage drop detected\n");
}
/* make sure we are running in 24hour mode */
if (!(ds1307->regs[0] & RX8025_BIT_2412)) {
u8 hour;
/* switch to 24 hour mode */
i2c_smbus_write_byte_data(client,
RX8025_REG_CTRL1 << 4 | 0x08,
ds1307->regs[0] |
RX8025_BIT_2412);
tmp = i2c_smbus_read_i2c_block_data(ds1307->client,
RX8025_REG_CTRL1 << 4 | 0x08, 2, buf);
if (tmp != 2) {
dev_dbg(&client->dev, "read error %d\n", tmp);
err = -EIO;
goto exit;
}
/* correct hour */
hour = bcd2bin(ds1307->regs[DS1307_REG_HOUR]);
if (hour == 12)
hour = 0;
if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
hour += 12;
i2c_smbus_write_byte_data(client,
DS1307_REG_HOUR << 4 | 0x08,
hour);
}
break;
case ds_1388:
ds1307->offset = 1; /* Seconds starts at 1 */
break;
case mcp794xx:
rtc_ops = &mcp794xx_rtc_ops;
if (ds1307->client->irq > 0 && chip->alarm) {
INIT_WORK(&ds1307->work, mcp794xx_work);
want_irq = true;
}
break;
default:
break;
}
read_rtc:
/* read RTC registers */
tmp = ds1307->read_block_data(ds1307->client, ds1307->offset, 8, buf);
if (tmp != 8) {
dev_dbg(&client->dev, "read error %d\n", tmp);
err = -EIO;
goto exit;
}
/*
* minimal sanity checking; some chips (like DS1340) don't
* specify the extra bits as must-be-zero, but there are
* still a few values that are clearly out-of-range.
*/
tmp = ds1307->regs[DS1307_REG_SECS];
switch (ds1307->type) {
case ds_1307:
case m41t00:
/* clock halted? turn it on, so clock can tick. */
if (tmp & DS1307_BIT_CH) {
i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
dev_warn(&client->dev, "SET TIME!\n");
goto read_rtc;
}
break;
case ds_1338:
/* clock halted? turn it on, so clock can tick. */
if (tmp & DS1307_BIT_CH)
i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
/* oscillator fault? clear flag, and warn */
if (ds1307->regs[DS1307_REG_CONTROL] & DS1338_BIT_OSF) {
i2c_smbus_write_byte_data(client, DS1307_REG_CONTROL,
ds1307->regs[DS1307_REG_CONTROL]
& ~DS1338_BIT_OSF);
dev_warn(&client->dev, "SET TIME!\n");
goto read_rtc;
}
break;
case ds_1340:
/* clock halted? turn it on, so clock can tick. */
if (tmp & DS1340_BIT_nEOSC)
i2c_smbus_write_byte_data(client, DS1307_REG_SECS, 0);
tmp = i2c_smbus_read_byte_data(client, DS1340_REG_FLAG);
if (tmp < 0) {
dev_dbg(&client->dev, "read error %d\n", tmp);
err = -EIO;
goto exit;
}
/* oscillator fault? clear flag, and warn */
if (tmp & DS1340_BIT_OSF) {
i2c_smbus_write_byte_data(client, DS1340_REG_FLAG, 0);
dev_warn(&client->dev, "SET TIME!\n");
}
break;
case mcp794xx:
/* make sure that the backup battery is enabled */
if (!(ds1307->regs[DS1307_REG_WDAY] & MCP794XX_BIT_VBATEN)) {
i2c_smbus_write_byte_data(client, DS1307_REG_WDAY,
ds1307->regs[DS1307_REG_WDAY]
| MCP794XX_BIT_VBATEN);
}
/* clock halted? turn it on, so clock can tick. */
if (!(tmp & MCP794XX_BIT_ST)) {
i2c_smbus_write_byte_data(client, DS1307_REG_SECS,
MCP794XX_BIT_ST);
dev_warn(&client->dev, "SET TIME!\n");
goto read_rtc;
}
break;
default:
break;
}
tmp = ds1307->regs[DS1307_REG_HOUR];
switch (ds1307->type) {
case ds_1340:
case m41t00:
/*
* NOTE: ignores century bits; fix before deploying
* systems that will run through year 2100.
*/
break;
case rx_8025:
break;
default:
if (!(tmp & DS1307_BIT_12HR))
break;
/*
* Be sure we're in 24 hour mode. Multi-master systems
* take note...
*/
tmp = bcd2bin(tmp & 0x1f);
if (tmp == 12)
tmp = 0;
if (ds1307->regs[DS1307_REG_HOUR] & DS1307_BIT_PM)
tmp += 12;
i2c_smbus_write_byte_data(client,
ds1307->offset + DS1307_REG_HOUR,
bin2bcd(tmp));
}
device_set_wakeup_capable(&client->dev, want_irq);
ds1307->rtc = devm_rtc_device_register(&client->dev, client->name,
rtc_ops, THIS_MODULE);
if (IS_ERR(ds1307->rtc)) {
return PTR_ERR(ds1307->rtc);
}
if (want_irq) {
err = request_irq(client->irq, ds1307_irq, IRQF_SHARED,
ds1307->rtc->name, client);
if (err) {
client->irq = 0;
dev_err(&client->dev, "unable to request IRQ!\n");
} else {
set_bit(HAS_ALARM, &ds1307->flags);
dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
}
}
if (chip->nvram_size) {
ds1307->nvram = devm_kzalloc(&client->dev,
sizeof(struct bin_attribute),
GFP_KERNEL);
if (!ds1307->nvram) {
dev_err(&client->dev, "cannot allocate memory for nvram sysfs\n");
} else {
ds1307->nvram->attr.name = "nvram";
ds1307->nvram->attr.mode = S_IRUGO | S_IWUSR;
sysfs_bin_attr_init(ds1307->nvram);
ds1307->nvram->read = ds1307_nvram_read;
ds1307->nvram->write = ds1307_nvram_write;
ds1307->nvram->size = chip->nvram_size;
ds1307->nvram_offset = chip->nvram_offset;
err = sysfs_create_bin_file(&client->dev.kobj,
ds1307->nvram);
if (err) {
dev_err(&client->dev,
"unable to create sysfs file: %s\n",
ds1307->nvram->attr.name);
} else {
set_bit(HAS_NVRAM, &ds1307->flags);
dev_info(&client->dev, "%zu bytes nvram\n",
ds1307->nvram->size);
}
}
}
return 0;
exit:
return err;
}
static int ds1307_remove(struct i2c_client *client)
{
struct ds1307 *ds1307 = i2c_get_clientdata(client);
if (test_and_clear_bit(HAS_ALARM, &ds1307->flags)) {
free_irq(client->irq, client);
cancel_work_sync(&ds1307->work);
}
if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
return 0;
}
static struct i2c_driver ds1307_driver = {
.driver = {
.name = "rtc-ds1307",
.owner = THIS_MODULE,
},
.probe = ds1307_probe,
.remove = ds1307_remove,
.id_table = ds1307_id,
};
module_i2c_driver(ds1307_driver);
MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");
MODULE_LICENSE("GPL");
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