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linux/drivers/rtc/rtc-s35390a.c
Rob Herring (Arm) da1531ecf1 rtc: s35390a: Drop vendorless compatible string from match table 
There's no need to list "s35390a" in the DT match table. The I2C core
will strip any vendor prefix and match against the i2c_device_id table
which has an "s35390a" entry.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20240826191321.1410668-1-robh@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2024-09-12 00:15:49 +02:00

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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" },
{ }
};
MODULE_DEVICE_TABLE(i2c, s35390a_id);
static const __maybe_unused struct of_device_id s35390a_of_match[] = {
{ .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;
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]);
return s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
}
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);
/* 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)
{
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;
set_bit(RTC_FEATURE_ALARM_RES_MINUTE, s35390a->rtc->features);
clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, s35390a->rtc->features );
if (status1 & S35390A_FLAG_INT2)
rtc_update_irq(s35390a->rtc, 1, RTC_AF);
return devm_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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