[mirror_ubuntu-focal-kernel.git] / drivers / rtc / rtc-s35390a.c

// 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 struct i2c_driver s35390a_driver;

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)) {
		err = -ENODEV;
		goto exit;
	}

	s35390a = devm_kzalloc(dev, sizeof(struct s35390a), GFP_KERNEL);
	if (!s35390a) {
		err = -ENOMEM;
		goto exit;
	}

	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] = i2c_new_dummy(client->adapter,
					client->addr + i);
		if (!s35390a->client[i]) {
			dev_err(dev, "Address %02x unavailable\n",
				client->addr + i);
			err = -EBUSY;
			goto exit_dummy;
		}
	}

	err_read = s35390a_read_status(s35390a, &status1);
	if (err_read < 0) {
		err = err_read;
		dev_err(dev, "error resetting chip\n");
		goto exit_dummy;
	}

	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");
			goto exit_dummy;
		}
	} else {
		err = s35390a_disable_test_mode(s35390a);
		if (err < 0) {
			dev_err(dev, "error disabling test mode\n");
			goto exit_dummy;
		}
	}

	device_set_wakeup_capable(dev, 1);

	s35390a->rtc = devm_rtc_device_register(dev, s35390a_driver.driver.name,
						&s35390a_rtc_ops, THIS_MODULE);

	if (IS_ERR(s35390a->rtc)) {
		err = PTR_ERR(s35390a->rtc);
		goto exit_dummy;
	}

	/* 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 0;

exit_dummy:
	for (i = 1; i < 8; ++i)
		if (s35390a->client[i])
			i2c_unregister_device(s35390a->client[i]);

exit:
	return err;
}

static int s35390a_remove(struct i2c_client *client)
{
	unsigned int i;
	struct s35390a *s35390a = i2c_get_clientdata(client);

	for (i = 1; i < 8; ++i)
		if (s35390a->client[i])
			i2c_unregister_device(s35390a->client[i]);

	return 0;
}

static struct i2c_driver s35390a_driver = {
	.driver		= {
		.name	= "rtc-s35390a",
		.of_match_table = of_match_ptr(s35390a_of_match),
	},
	.probe		= s35390a_probe,
	.remove		= s35390a_remove,
	.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");
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
c46288b0 BB	2	/*
	3	* Seiko Instruments S-35390A RTC Driver
	4	*
	5	* Copyright (c) 2007 Byron Bradley
c46288b0 BB	6	*/
	7
	8	#include <linux/module.h>
	9	#include <linux/rtc.h>
	10	#include <linux/i2c.h>
	11	#include <linux/bitrev.h>
	12	#include <linux/bcd.h>
	13	#include <linux/slab.h>
8e6583f1	14	#include <linux/delay.h>
c46288b0 BB	15
	16	#define S35390A_CMD_STATUS1 0
	17	#define S35390A_CMD_STATUS2 1
	18	#define S35390A_CMD_TIME1 2
542dd33a ML	19	#define S35390A_CMD_TIME2 3
542dd33a ML	20	#define S35390A_CMD_INT2_REG1 5
c46288b0 BB	21
	22	#define S35390A_BYTE_YEAR 0
	23	#define S35390A_BYTE_MONTH 1
	24	#define S35390A_BYTE_DAY 2
	25	#define S35390A_BYTE_WDAY 3
	26	#define S35390A_BYTE_HOURS 4
	27	#define S35390A_BYTE_MINS 5
	28	#define S35390A_BYTE_SECS 6
	29
542dd33a ML	30	#define S35390A_ALRM_BYTE_WDAY 0
	31	#define S35390A_ALRM_BYTE_HOURS 1
	32	#define S35390A_ALRM_BYTE_MINS 2
	33
3bd32722	34	/* flags for STATUS1 */
097aa24b RL	35	#define S35390A_FLAG_POC BIT(0)
	36	#define S35390A_FLAG_BLD BIT(1)
	37	#define S35390A_FLAG_INT2 BIT(2)
	38	#define S35390A_FLAG_24H BIT(6)
	39	#define S35390A_FLAG_RESET BIT(7)
3bd32722 UKK	40
3bd32722 UKK	41	/* flag for STATUS2 */
097aa24b	42	#define S35390A_FLAG_TEST BIT(0)
542dd33a	43
a86bd904 RL	44	/* INT2 pin output mode */
a86bd904 RL	45	#define S35390A_INT2_MODE_MASK 0x0E
542dd33a	46	#define S35390A_INT2_MODE_NOINTR 0x00
a86bd904 RL	47	#define S35390A_INT2_MODE_ALARM BIT(1) /* INT2AE */
	48	#define S35390A_INT2_MODE_PMIN_EDG BIT(2) /* INT2ME */
	49	#define S35390A_INT2_MODE_FREQ BIT(3) /* INT2FE */
	50	#define S35390A_INT2_MODE_PMIN (BIT(3) \| BIT(2)) /* INT2FE \| INT2ME */
542dd33a	51
3760f736 JD	52	static const struct i2c_device_id s35390a_id[] = {
	53	{ "s35390a", 0 },
	54	{ }
	55	};
	56	MODULE_DEVICE_TABLE(i2c, s35390a_id);
	57
21f27432 JMC	58	static const struct of_device_id s35390a_of_match[] = {
	59	{ .compatible = "s35390a" },
	60	{ .compatible = "sii,s35390a" },
	61	{ }
	62	};
	63	MODULE_DEVICE_TABLE(of, s35390a_of_match);
	64
c46288b0 BB	65	struct s35390a {
	66	struct i2c_client *client[8];
	67	struct rtc_device *rtc;
	68	int twentyfourhour;
	69	};
	70
	71	static int s35390a_set_reg(struct s35390a s35390a, int reg, char buf, int len)
	72	{
	73	struct i2c_client *client = s35390a->client[reg];
	74	struct i2c_msg msg[] = {
65659f63 S	75	{
	76	.addr = client->addr,
	77	.len = len,
	78	.buf = buf
	79	},
c46288b0 BB	80	};
	81
	82	if ((i2c_transfer(client->adapter, msg, 1)) != 1)
	83	return -EIO;
	84
	85	return 0;
	86	}
	87
	88	static int s35390a_get_reg(struct s35390a s35390a, int reg, char buf, int len)
	89	{
	90	struct i2c_client *client = s35390a->client[reg];
	91	struct i2c_msg msg[] = {
65659f63 S	92	{
	93	.addr = client->addr,
	94	.flags = I2C_M_RD,
	95	.len = len,
	96	.buf = buf
	97	},
c46288b0 BB	98	};
	99
	100	if ((i2c_transfer(client->adapter, msg, 1)) != 1)
	101	return -EIO;
	102
	103	return 0;
	104	}
	105
16486d0c	106	static int s35390a_init(struct s35390a *s35390a)
c46288b0	107	{
ef0f02fd	108	u8 buf;
8e6583f1 UKK	109	int ret;
8e6583f1 UKK	110	unsigned initcount = 0;
c46288b0	111
8e6583f1 UKK	112	/*
	113	* At least one of POC and BLD are set, so reinitialise chip. Keeping
	114	* this information in the hardware to know later that the time isn't
	115	* valid is unfortunately not possible because POC and BLD are cleared
	116	* on read. So the reset is best done now.
	117	*
	118	* The 24H bit is kept over reset, so set it already here.
	119	*/
	120	initialize:
8e6583f1 UKK	121	buf = S35390A_FLAG_RESET \| S35390A_FLAG_24H;
	122	ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
	123
	124	if (ret < 0)
	125	return ret;
	126
	127	ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1);
	128	if (ret < 0)
	129	return ret;
	130
	131	if (buf & (S35390A_FLAG_POC \| S35390A_FLAG_BLD)) {
	132	/* Try up to five times to reset the chip */
	133	if (initcount < 5) {
	134	++initcount;
	135	goto initialize;
	136	} else
	137	return -EIO;
	138	}
	139
	140	return 1;
c46288b0 BB	141	}
c46288b0 BB	142
16486d0c FL	143	/*
	144	* Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset.
	145	* To keep the information if an irq is pending, pass the value read from
	146	* STATUS1 to the caller.
	147	*/
	148	static int s35390a_read_status(struct s35390a s35390a, char status1)
	149	{
	150	int ret;
	151
	152	ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1);
	153	if (ret < 0)
	154	return ret;
	155
	156	if (*status1 & S35390A_FLAG_POC) {
	157	/*
	158	* Do not communicate for 0.5 seconds since the power-on
	159	* detection circuit is in operation.
	160	*/
	161	msleep(500);
	162	return 1;
	163	} else if (*status1 & S35390A_FLAG_BLD)
	164	return 1;
	165	/*
	166	* If both POC and BLD are unset everything is fine.
	167	*/
	168	return 0;
	169	}
	170
c46288b0 BB	171	static int s35390a_disable_test_mode(struct s35390a *s35390a)
	172	{
	173	char buf[1];
	174
	175	if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0)
	176	return -EIO;
	177
	178	if (!(buf[0] & S35390A_FLAG_TEST))
	179	return 0;
	180
	181	buf[0] &= ~S35390A_FLAG_TEST;
	182	return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf));
	183	}
	184
	185	static char s35390a_hr2reg(struct s35390a *s35390a, int hour)
	186	{
	187	if (s35390a->twentyfourhour)
fe20ba70	188	return bin2bcd(hour);
c46288b0 BB	189
c46288b0 BB	190	if (hour < 12)
fe20ba70	191	return bin2bcd(hour);
c46288b0	192
fe20ba70	193	return 0x40 \| bin2bcd(hour - 12);
c46288b0 BB	194	}
	195
	196	static int s35390a_reg2hr(struct s35390a *s35390a, char reg)
	197	{
	198	unsigned hour;
	199
	200	if (s35390a->twentyfourhour)
fe20ba70	201	return bcd2bin(reg & 0x3f);
c46288b0	202
fe20ba70	203	hour = bcd2bin(reg & 0x3f);
c46288b0 BB	204	if (reg & 0x40)
	205	hour += 12;
	206
	207	return hour;
	208	}
	209
779e1aab	210	static int s35390a_rtc_set_time(struct device dev, struct rtc_time tm)
c46288b0	211	{
779e1aab	212	struct i2c_client *client = to_i2c_client(dev);
c46288b0 BB	213	struct s35390a *s35390a = i2c_get_clientdata(client);
c46288b0 BB	214	int i, err;
16486d0c	215	char buf[7], status;
c46288b0 BB	216
	217	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, "
	218	"mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
	219	tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
	220	tm->tm_wday);
	221
16486d0c FL	222	if (s35390a_read_status(s35390a, &status) == 1)
	223	s35390a_init(s35390a);
	224
fe20ba70 AB	225	buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100);
	226	buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1);
	227	buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday);
	228	buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday);
c46288b0	229	buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour);
fe20ba70 AB	230	buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min);
fe20ba70 AB	231	buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec);
c46288b0 BB	232
	233	/* This chip expects the bits of each byte to be in reverse order */
	234	for (i = 0; i < 7; ++i)
	235	buf[i] = bitrev8(buf[i]);
	236
	237	err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
	238
	239	return err;
	240	}
	241
779e1aab	242	static int s35390a_rtc_read_time(struct device dev, struct rtc_time tm)
c46288b0	243	{
779e1aab	244	struct i2c_client *client = to_i2c_client(dev);
c46288b0	245	struct s35390a *s35390a = i2c_get_clientdata(client);
16486d0c	246	char buf[7], status;
c46288b0 BB	247	int i, err;
c46288b0 BB	248
16486d0c FL	249	if (s35390a_read_status(s35390a, &status) == 1)
	250	return -EINVAL;
	251
c46288b0 BB	252	err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf));
	253	if (err < 0)
	254	return err;
	255
	256	/* This chip returns the bits of each byte in reverse order */
	257	for (i = 0; i < 7; ++i)
	258	buf[i] = bitrev8(buf[i]);
	259
fe20ba70 AB	260	tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]);
fe20ba70 AB	261	tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]);
c46288b0	262	tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]);
fe20ba70 AB	263	tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]);
	264	tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]);
	265	tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1;
	266	tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100;
c46288b0 BB	267
	268	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, "
	269	"mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec,
	270	tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year,
	271	tm->tm_wday);
	272
bb530199	273	return 0;
c46288b0 BB	274	}
c46288b0 BB	275
779e1aab	276	static int s35390a_rtc_set_alarm(struct device dev, struct rtc_wkalrm alm)
542dd33a	277	{
779e1aab	278	struct i2c_client *client = to_i2c_client(dev);
542dd33a ML	279	struct s35390a *s35390a = i2c_get_clientdata(client);
	280	char buf[3], sts = 0;
	281	int err, i;
	282
	283	dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\
	284	"mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec,
	285	alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday,
	286	alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday);
	287
c0e12848 RL	288	if (alm->time.tm_sec != 0)
	289	dev_warn(&client->dev, "Alarms are only supported on a per minute basis!\n");
	290
5227e8a2	291	/* disable interrupt (which deasserts the irq line) */
542dd33a ML	292	err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
	293	if (err < 0)
	294	return err;
	295
5227e8a2	296	/* clear pending interrupt (in STATUS1 only), if any */
542dd33a ML	297	err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts));
	298	if (err < 0)
	299	return err;
	300
	301	if (alm->enabled)
	302	sts = S35390A_INT2_MODE_ALARM;
	303	else
	304	sts = S35390A_INT2_MODE_NOINTR;
	305
542dd33a ML	306	/* set interupt mode*/
	307	err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
	308	if (err < 0)
	309	return err;
	310
	311	if (alm->time.tm_wday != -1)
	312	buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) \| 0x80;
f87e904d UKK	313	else
f87e904d UKK	314	buf[S35390A_ALRM_BYTE_WDAY] = 0;
542dd33a ML	315
	316	buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a,
	317	alm->time.tm_hour) \| 0x80;
	318	buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) \| 0x80;
	319
	320	if (alm->time.tm_hour >= 12)
	321	buf[S35390A_ALRM_BYTE_HOURS] \|= 0x40;
	322
	323	for (i = 0; i < 3; ++i)
	324	buf[i] = bitrev8(buf[i]);
	325
	326	err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf,
	327	sizeof(buf));
	328
	329	return err;
	330	}
	331
779e1aab	332	static int s35390a_rtc_read_alarm(struct device dev, struct rtc_wkalrm alm)
542dd33a	333	{
779e1aab	334	struct i2c_client *client = to_i2c_client(dev);
542dd33a ML	335	struct s35390a *s35390a = i2c_get_clientdata(client);
	336	char buf[3], sts;
	337	int i, err;
	338
	339	err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts));
	340	if (err < 0)
	341	return err;
	342
a86bd904	343	if ((sts & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) {
f87e904d UKK	344	/*
	345	* When the alarm isn't enabled, the register to configure
	346	* the alarm time isn't accessible.
	347	*/
	348	alm->enabled = 0;
	349	return 0;
	350	} else {
	351	alm->enabled = 1;
	352	}
542dd33a ML	353
	354	err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf));
	355	if (err < 0)
	356	return err;
	357
	358	/* This chip returns the bits of each byte in reverse order */
f87e904d	359	for (i = 0; i < 3; ++i)
542dd33a	360	buf[i] = bitrev8(buf[i]);
542dd33a	361
f87e904d UKK	362	/*
	363	* B0 of the three matching registers is an enable flag. Iff it is set
	364	* the configured value is used for matching.
	365	*/
	366	if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80)
	367	alm->time.tm_wday =
	368	bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80);
	369
	370	if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80)
	371	alm->time.tm_hour =
	372	s35390a_reg2hr(s35390a,
	373	buf[S35390A_ALRM_BYTE_HOURS] & ~0x80);
	374
	375	if (buf[S35390A_ALRM_BYTE_MINS] & 0x80)
	376	alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80);
	377
	378	/* alarm triggers always at s=0 */
	379	alm->time.tm_sec = 0;
542dd33a ML	380
	381	dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n",
	382	__func__, alm->time.tm_min, alm->time.tm_hour,
	383	alm->time.tm_wday);
	384
	385	return 0;
	386	}
	387
7a1fe407 FL	388	static int s35390a_rtc_ioctl(struct device *dev, unsigned int cmd,
	389	unsigned long arg)
	390	{
	391	struct i2c_client *client = to_i2c_client(dev);
	392	struct s35390a *s35390a = i2c_get_clientdata(client);
	393	char sts;
	394	int err;
	395
	396	switch (cmd) {
	397	case RTC_VL_READ:
	398	/* s35390a_reset set lowvoltage flag and init RTC if needed */
	399	err = s35390a_read_status(s35390a, &sts);
	400	if (err < 0)
	401	return err;
	402	if (copy_to_user((void __user *)arg, &err, sizeof(int)))
	403	return -EFAULT;
	404	break;
	405	case RTC_VL_CLR:
	406	/* update flag and clear register */
	407	err = s35390a_init(s35390a);
	408	if (err < 0)
	409	return err;
	410	break;
	411	default:
	412	return -ENOIOCTLCMD;
	413	}
	414
	415	return 0;
	416	}
	417
c46288b0 BB	418	static const struct rtc_class_ops s35390a_rtc_ops = {
	419	.read_time = s35390a_rtc_read_time,
	420	.set_time = s35390a_rtc_set_time,
542dd33a ML	421	.set_alarm = s35390a_rtc_set_alarm,
542dd33a ML	422	.read_alarm = s35390a_rtc_read_alarm,
7a1fe407	423	.ioctl = s35390a_rtc_ioctl,
c46288b0 BB	424	};
	425
	426	static struct i2c_driver s35390a_driver;
	427
d2653e92 JD	428	static int s35390a_probe(struct i2c_client *client,
d2653e92 JD	429	const struct i2c_device_id *id)
c46288b0	430	{
16486d0c	431	int err, err_read;
c46288b0 BB	432	unsigned int i;
c46288b0 BB	433	struct s35390a *s35390a;
3bd32722	434	char buf, status1;
03279634	435	struct device *dev = &client->dev;
c46288b0 BB	436
	437	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
	438	err = -ENODEV;
	439	goto exit;
	440	}
	441
03279634	442	s35390a = devm_kzalloc(dev, sizeof(struct s35390a), GFP_KERNEL);
c46288b0 BB	443	if (!s35390a) {
	444	err = -ENOMEM;
	445	goto exit;
	446	}
	447
	448	s35390a->client[0] = client;
	449	i2c_set_clientdata(client, s35390a);
	450
	451	/* This chip uses multiple addresses, use dummy devices for them */
	452	for (i = 1; i < 8; ++i) {
	453	s35390a->client[i] = i2c_new_dummy(client->adapter,
60b129d7	454	client->addr + i);
c46288b0	455	if (!s35390a->client[i]) {
03279634 RL	456	dev_err(dev, "Address %02x unavailable\n",
03279634 RL	457	client->addr + i);
c46288b0 BB	458	err = -EBUSY;
	459	goto exit_dummy;
	460	}
	461	}
	462
16486d0c FL	463	err_read = s35390a_read_status(s35390a, &status1);
	464	if (err_read < 0) {
	465	err = err_read;
03279634	466	dev_err(dev, "error resetting chip\n");
c46288b0 BB	467	goto exit_dummy;
	468	}
	469
3bd32722	470	if (status1 & S35390A_FLAG_24H)
c46288b0 BB	471	s35390a->twentyfourhour = 1;
	472	else
	473	s35390a->twentyfourhour = 0;
	474
3bd32722 UKK	475	if (status1 & S35390A_FLAG_INT2) {
	476	/* disable alarm (and maybe test mode) */
	477	buf = 0;
	478	err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1);
	479	if (err < 0) {
03279634	480	dev_err(dev, "error disabling alarm");
3bd32722 UKK	481	goto exit_dummy;
	482	}
	483	} else {
	484	err = s35390a_disable_test_mode(s35390a);
	485	if (err < 0) {
03279634	486	dev_err(dev, "error disabling test mode\n");
3bd32722 UKK	487	goto exit_dummy;
	488	}
	489	}
	490
03279634	491	device_set_wakeup_capable(dev, 1);
542dd33a	492
03279634 RL	493	s35390a->rtc = devm_rtc_device_register(dev, s35390a_driver.driver.name,
03279634 RL	494	&s35390a_rtc_ops, THIS_MODULE);
c46288b0 BB	495
	496	if (IS_ERR(s35390a->rtc)) {
	497	err = PTR_ERR(s35390a->rtc);
	498	goto exit_dummy;
	499	}
3bd32722	500
c0e12848 RL	501	/* supports per-minute alarms only, therefore set uie_unsupported */
	502	s35390a->rtc->uie_unsupported = 1;
	503
3bd32722 UKK	504	if (status1 & S35390A_FLAG_INT2)
	505	rtc_update_irq(s35390a->rtc, 1, RTC_AF);
	506
c46288b0 BB	507	return 0;
	508
	509	exit_dummy:
	510	for (i = 1; i < 8; ++i)
	511	if (s35390a->client[i])
	512	i2c_unregister_device(s35390a->client[i]);
c46288b0 BB	513
	514	exit:
	515	return err;
	516	}
	517
	518	static int s35390a_remove(struct i2c_client *client)
	519	{
	520	unsigned int i;
c46288b0	521	struct s35390a *s35390a = i2c_get_clientdata(client);
b4cd3d6a	522
c46288b0 BB	523	for (i = 1; i < 8; ++i)
	524	if (s35390a->client[i])
	525	i2c_unregister_device(s35390a->client[i]);
	526
c46288b0 BB	527	return 0;
	528	}
	529
	530	static struct i2c_driver s35390a_driver = {
	531	.driver = {
	532	.name = "rtc-s35390a",
21f27432	533	.of_match_table = of_match_ptr(s35390a_of_match),
c46288b0 BB	534	},
	535	.probe = s35390a_probe,
	536	.remove = s35390a_remove,
3760f736	537	.id_table = s35390a_id,
c46288b0 BB	538	};
c46288b0 BB	539
0abc9201	540	module_i2c_driver(s35390a_driver);
c46288b0 BB	541
	542	MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");
	543	MODULE_DESCRIPTION("S35390A RTC driver");
	544	MODULE_LICENSE("GPL");