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linux/drivers/rtc/rtc-s35390a.c
Alexandre Belloni 9e8a968fe3 rtc: s35390a: set range 
This is a standard BCD RTC that will fail in 2100.

Link: https://lore.kernel.org/r/20191016200848.30246-2-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2019-10-19 22:33:05 +02:00

517 lines
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Seiko Instruments S-35390A RTC Driver
*
* Copyright (c) 2007 Byron Bradley
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/i2c.h>
#include <linux/bitrev.h>
#include <linux/bcd.h>
#include <linux/slab.h>
#include <linux/delay.h>
#define S35390A_CMD_STATUS1 0
#define S35390A_CMD_STATUS2 1
#define S35390A_CMD_TIME1 2
#define S35390A_CMD_TIME2 3
#define S35390A_CMD_INT2_REG1 5
#define S35390A_BYTE_YEAR 0
#define S35390A_BYTE_MONTH 1
#define S35390A_BYTE_DAY 2
#define S35390A_BYTE_WDAY 3
#define S35390A_BYTE_HOURS 4
#define S35390A_BYTE_MINS 5
#define S35390A_BYTE_SECS 6
#define S35390A_ALRM_BYTE_WDAY 0
#define S35390A_ALRM_BYTE_HOURS 1
#define S35390A_ALRM_BYTE_MINS 2
/* flags for STATUS1 */
#define S35390A_FLAG_POC BIT(0)
#define S35390A_FLAG_BLD BIT(1)
#define S35390A_FLAG_INT2 BIT(2)
#define S35390A_FLAG_24H BIT(6)
#define S35390A_FLAG_RESET BIT(7)
/* flag for STATUS2 */
#define S35390A_FLAG_TEST BIT(0)
/* INT2 pin output mode */
#define S35390A_INT2_MODE_MASK 0x0E
#define S35390A_INT2_MODE_NOINTR 0x00
#define S35390A_INT2_MODE_ALARM BIT(1) /* INT2AE */
#define S35390A_INT2_MODE_PMIN_EDG BIT(2) /* INT2ME */
#define S35390A_INT2_MODE_FREQ BIT(3) /* INT2FE */
#define S35390A_INT2_MODE_PMIN (BIT(3) | BIT(2)) /* INT2FE | INT2ME */
static const struct i2c_device_id s35390a_id[] = {
{ "s35390a", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, s35390a_id);
static const struct of_device_id s35390a_of_match[] = {
{ .compatible = "s35390a" },
{ .compatible = "sii,s35390a" },
{ }
};
MODULE_DEVICE_TABLE(of, s35390a_of_match);
struct s35390a {
struct i2c_client *client[8];
struct rtc_device *rtc;
int twentyfourhour;
};
static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len)
{
struct i2c_client *client = s35390a->client[reg];
struct i2c_msg msg[] = {
{
.addr = client->addr,
.len = len,
.buf = buf
},
};
if ((i2c_transfer(client->adapter, msg, 1)) != 1)
return -EIO;
return 0;
}
static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len)
{
struct i2c_client *client = s35390a->client[reg];
struct i2c_msg msg[] = {
{
.addr = client->addr,
.flags = I2C_M_RD,
.len = len,
.buf = buf
},
};
if ((i2c_transfer(client->adapter, msg, 1)) != 1)
return -EIO;
return 0;
}
static int s35390a_init(struct s35390a *s35390a)
{
u8 buf;
int ret;
unsigned initcount = 0;
/*
* At least one of POC and BLD are set, so reinitialise chip. Keeping
* this information in the hardware to know later that the time isn't
* valid is unfortunately not possible because POC and BLD are cleared
* on read. So the reset is best done now.
*
* The 24H bit is kept over reset, so set it already here.
*/
initialize:
buf = S35390A_FLAG_RESET | S35390A_FLAG_24H;
ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
if (ret < 0)
return ret;
ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
if (ret < 0)
return ret;
if (buf & (S35390A_FLAG_POC | S35390A_FLAG_BLD)) {
/* Try up to five times to reset the chip */
if (initcount < 5) {
++initcount;
goto initialize;
} else
return -EIO;
}
return 1;
}
/*
* Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset.
* To keep the information if an irq is pending, pass the value read from
* STATUS1 to the caller.
*/
static int s35390a_read_status(struct s35390a *s35390a, char *status1)
{
int ret;
ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1);
if (ret < 0)
return ret;
if (*status1 & S35390A_FLAG_POC) {
/*
* Do not communicate for 0.5 seconds since the power-on
* detection circuit is in operation.
*/
msleep(500);
return 1;
} else if (*status1 & S35390A_FLAG_BLD)
return 1;
/*
* If both POC and BLD are unset everything is fine.
*/
return 0;
}
static int s35390a_disable_test_mode(struct s35390a *s35390a)
{
char buf[1];
if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
return -EIO;
if (!(buf[0] & S35390A_FLAG_TEST))
return 0;
buf[0] &= ~S35390A_FLAG_TEST;
return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
}
static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
{
if (s35390a->twentyfourhour)
return bin2bcd(hour);
if (hour < 12)
return bin2bcd(hour);
return 0x40 | bin2bcd(hour - 12);
}
static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
{
unsigned hour;
if (s35390a->twentyfourhour)
return bcd2bin(reg & 0x3f);
hour = bcd2bin(reg & 0x3f);
if (reg & 0x40)
hour += 12;
return hour;
}
static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
struct s35390a *s35390a = i2c_get_clientdata(client);
int i, err;
char buf[7], status;
dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
"mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
tm->tm_wday);
if (s35390a_read_status(s35390a, &status) == 1)
s35390a_init(s35390a);
buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
/* This chip expects the bits of each byte to be in reverse order */
for (i = 0; i < 7; ++i)
buf[i] = bitrev8(buf[i]);
err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
return err;
}
static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
struct s35390a *s35390a = i2c_get_clientdata(client);
char buf[7], status;
int i, err;
if (s35390a_read_status(s35390a, &status) == 1)
return -EINVAL;
err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
if (err < 0)
return err;
/* This chip returns the bits of each byte in reverse order */
for (i = 0; i < 7; ++i)
buf[i] = bitrev8(buf[i]);
tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]);
tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]);
tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]);
tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]);
tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1;
tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100;
dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
"mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
tm->tm_wday);
return 0;
}
static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct i2c_client *client = to_i2c_client(dev);
struct s35390a *s35390a = i2c_get_clientdata(client);
char buf[3], sts = 0;
int err, i;
dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\
"mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec,
alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday,
alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday);
if (alm->time.tm_sec != 0)
dev_warn(&client->dev, "Alarms are only supported on a per minute basis!\n");
/* disable interrupt (which deasserts the irq line) */
err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
if (err < 0)
return err;
/* clear pending interrupt (in STATUS1 only), if any */
err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
if (err < 0)
return err;
if (alm->enabled)
sts = S35390A_INT2_MODE_ALARM;
else
sts = S35390A_INT2_MODE_NOINTR;
/* set interupt mode*/
err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
if (err < 0)
return err;
if (alm->time.tm_wday != -1)
buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80;
else
buf[S35390A_ALRM_BYTE_WDAY] = 0;
buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
alm->time.tm_hour) | 0x80;
buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80;
if (alm->time.tm_hour >= 12)
buf[S35390A_ALRM_BYTE_HOURS] |= 0x40;
for (i = 0; i < 3; ++i)
buf[i] = bitrev8(buf[i]);
err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf,
sizeof(buf));
return err;
}
static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
{
struct i2c_client *client = to_i2c_client(dev);
struct s35390a *s35390a = i2c_get_clientdata(client);
char buf[3], sts;
int i, err;
err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
if (err < 0)
return err;
if ((sts & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) {
/*
* When the alarm isn't enabled, the register to configure
* the alarm time isn't accessible.
*/
alm->enabled = 0;
return 0;
} else {
alm->enabled = 1;
}
err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf));
if (err < 0)
return err;
/* This chip returns the bits of each byte in reverse order */
for (i = 0; i < 3; ++i)
buf[i] = bitrev8(buf[i]);
/*
* B0 of the three matching registers is an enable flag. Iff it is set
* the configured value is used for matching.
*/
if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80)
alm->time.tm_wday =
bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80);
if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80)
alm->time.tm_hour =
s35390a_reg2hr(s35390a,
buf[S35390A_ALRM_BYTE_HOURS] & ~0x80);
if (buf[S35390A_ALRM_BYTE_MINS] & 0x80)
alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80);
/* alarm triggers always at s=0 */
alm->time.tm_sec = 0;
dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
__func__, alm->time.tm_min, alm->time.tm_hour,
alm->time.tm_wday);
return 0;
}
static int s35390a_rtc_ioctl(struct device *dev, unsigned int cmd,
unsigned long arg)
{
struct i2c_client *client = to_i2c_client(dev);
struct s35390a *s35390a = i2c_get_clientdata(client);
char sts;
int err;
switch (cmd) {
case RTC_VL_READ:
/* s35390a_reset set lowvoltage flag and init RTC if needed */
err = s35390a_read_status(s35390a, &sts);
if (err < 0)
return err;
if (copy_to_user((void __user *)arg, &err, sizeof(int)))
return -EFAULT;
break;
case RTC_VL_CLR:
/* update flag and clear register */
err = s35390a_init(s35390a);
if (err < 0)
return err;
break;
default:
return -ENOIOCTLCMD;
}
return 0;
}
static const struct rtc_class_ops s35390a_rtc_ops = {
.read_time = s35390a_rtc_read_time,
.set_time = s35390a_rtc_set_time,
.set_alarm = s35390a_rtc_set_alarm,
.read_alarm = s35390a_rtc_read_alarm,
.ioctl = s35390a_rtc_ioctl,
};
static int s35390a_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int err, err_read;
unsigned int i;
struct s35390a *s35390a;
char buf, status1;
struct device *dev = &client->dev;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
return -ENODEV;
s35390a = devm_kzalloc(dev, sizeof(struct s35390a), GFP_KERNEL);
if (!s35390a)
return -ENOMEM;
s35390a->client[0] = client;
i2c_set_clientdata(client, s35390a);
/* This chip uses multiple addresses, use dummy devices for them */
for (i = 1; i < 8; ++i) {
s35390a->client[i] = devm_i2c_new_dummy_device(dev,
client->adapter,
client->addr + i);
if (IS_ERR(s35390a->client[i])) {
dev_err(dev, "Address %02x unavailable\n",
client->addr + i);
return PTR_ERR(s35390a->client[i]);
}
}
s35390a->rtc = devm_rtc_allocate_device(dev);
if (IS_ERR(s35390a->rtc))
return PTR_ERR(s35390a->rtc);
err_read = s35390a_read_status(s35390a, &status1);
if (err_read < 0) {
dev_err(dev, "error resetting chip\n");
return err_read;
}
if (status1 & S35390A_FLAG_24H)
s35390a->twentyfourhour = 1;
else
s35390a->twentyfourhour = 0;
if (status1 & S35390A_FLAG_INT2) {
/* disable alarm (and maybe test mode) */
buf = 0;
err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1);
if (err < 0) {
dev_err(dev, "error disabling alarm");
return err;
}
} else {
err = s35390a_disable_test_mode(s35390a);
if (err < 0) {
dev_err(dev, "error disabling test mode\n");
return err;
}
}
device_set_wakeup_capable(dev, 1);
s35390a->rtc->ops = &s35390a_rtc_ops;
s35390a->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;
s35390a->rtc->range_max = RTC_TIMESTAMP_END_2099;
/* supports per-minute alarms only, therefore set uie_unsupported */
s35390a->rtc->uie_unsupported = 1;
if (status1 & S35390A_FLAG_INT2)
rtc_update_irq(s35390a->rtc, 1, RTC_AF);
return rtc_register_device(s35390a->rtc);
}
static struct i2c_driver s35390a_driver = {
.driver = {
.name = "rtc-s35390a",
.of_match_table = of_match_ptr(s35390a_of_match),
},
.probe = s35390a_probe,
.id_table = s35390a_id,
};
module_i2c_driver(s35390a_driver);
MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
MODULE_DESCRIPTION("S35390A RTC driver");
MODULE_LICENSE("GPL");
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