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Commit c46288b0 authored by Byron Bradley's avatar Byron Bradley Committed by Linus Torvalds
Browse files

rtc: add support for the S-35390A RTC chip 



This adds basic get/set time support for the Seiko Instruments S-35390A.
This chip communicates using I2C and is used on the QNAP TS-109/TS-209 NAS
devices.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarByron Bradley <byron.bbradley@gmail.com>
Acked-by: default avatarJean Delvare <khali@linux-fr.org>
Acked-by: default avatarDavid Brownell <david-b@pacbell.net>
Tested-by: default avatarTim Ellis <tim@ngndg.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fb78922c

drivers/rtc/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -250,6 +250,15 @@ config RTC_DRV_TWL92330 
	  platforms.  The support is integrated with the rest of

	  the Menelaus driver; it's not separate module.



config RTC_DRV_S35390A

	tristate "Seiko Instruments S-35390A"

	help

	  If you say yes here you will get support for the Seiko

	  Instruments S-35390A.



	  This driver can also be built as a module. If so the module

	  will be called rtc-s35390a.



endif # I2C



comment "SPI RTC drivers"

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ obj-$(CONFIG_RTC_DRV_R9701) += rtc-r9701.o 
obj-$(CONFIG_RTC_DRV_RS5C313)	+= rtc-rs5c313.o

obj-$(CONFIG_RTC_DRV_RS5C348)	+= rtc-rs5c348.o

obj-$(CONFIG_RTC_DRV_RS5C372)	+= rtc-rs5c372.o

obj-$(CONFIG_RTC_DRV_S35390A)	+= rtc-s35390a.o

obj-$(CONFIG_RTC_DRV_S3C)	+= rtc-s3c.o

obj-$(CONFIG_RTC_DRV_SA1100)	+= rtc-sa1100.o

obj-$(CONFIG_RTC_DRV_SH)	+= rtc-sh.o

drivers/rtc/rtc-s35390a.c

0 → 100644
+316 −0
Original line number Diff line number Diff line 
/*

 * Seiko Instruments S-35390A RTC Driver

 *

 * Copyright (c) 2007 Byron Bradley

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version

 * 2 of the License, or (at your option) any later version.

 */



#include <linux/module.h>

#include <linux/rtc.h>

#include <linux/i2c.h>

#include <linux/bitrev.h>

#include <linux/bcd.h>

#include <linux/slab.h>



#define S35390A_CMD_STATUS1	0

#define S35390A_CMD_STATUS2	1

#define S35390A_CMD_TIME1	2



#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_FLAG_POC	0x01

#define S35390A_FLAG_BLD	0x02

#define S35390A_FLAG_24H	0x40

#define S35390A_FLAG_RESET	0x80

#define S35390A_FLAG_TEST	0x01



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[] = {

		{ client->addr, 0, len, 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[] = {

		{ client->addr, I2C_M_RD, len, buf },

	};



	if ((i2c_transfer(client->adapter, msg, 1)) != 1)

		return -EIO;



	return 0;

}



static int s35390a_reset(struct s35390a *s35390a)

{

	char buf[1];



	if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)) < 0)

		return -EIO;



	if (!(buf[0] & (S35390A_FLAG_POC | S35390A_FLAG_BLD)))

		return 0;



	buf[0] |= (S35390A_FLAG_RESET | S35390A_FLAG_24H);

	buf[0] &= 0xf0;

	return s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));

}



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_set_datetime(struct i2c_client *client, struct rtc_time *tm)

{

	struct s35390a	*s35390a = i2c_get_clientdata(client);

	int i, err;

	char buf[7];



	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);



	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_get_datetime(struct i2c_client *client, struct rtc_time *tm)

{

	struct s35390a *s35390a = i2c_get_clientdata(client);

	char buf[7];

	int i, err;



	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 rtc_valid_tm(tm);

}



static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	return s35390a_get_datetime(to_i2c_client(dev), tm);

}



static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	return s35390a_set_datetime(to_i2c_client(dev), tm);

}



static const struct rtc_class_ops s35390a_rtc_ops = {

	.read_time	= s35390a_rtc_read_time,

	.set_time	= s35390a_rtc_set_time,

};



static struct i2c_driver s35390a_driver;



static int s35390a_probe(struct i2c_client *client)

{

	int err;

	unsigned int i;

	struct s35390a *s35390a;

	struct rtc_time tm;

	char buf[1];



	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {

		err = -ENODEV;

		goto exit;

	}



	s35390a = kzalloc(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, "rtc-s35390a");

		if (!s35390a->client[i]) {

			dev_err(&client->dev, "Address %02x unavailable\n",

						client->addr + i);

			err = -EBUSY;

			goto exit_dummy;

		}

	}



	err = s35390a_reset(s35390a);

	if (err < 0) {

		dev_err(&client->dev, "error resetting chip\n");

		goto exit_dummy;

	}



	err = s35390a_disable_test_mode(s35390a);

	if (err < 0) {

		dev_err(&client->dev, "error disabling test mode\n");

		goto exit_dummy;

	}



	err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf));

	if (err < 0) {

		dev_err(&client->dev, "error checking 12/24 hour mode\n");

		goto exit_dummy;

	}

	if (buf[0] & S35390A_FLAG_24H)

		s35390a->twentyfourhour = 1;

	else

		s35390a->twentyfourhour = 0;



	if (s35390a_get_datetime(client, &tm) < 0)

		dev_warn(&client->dev, "clock needs to be set\n");



	s35390a->rtc = rtc_device_register(s35390a_driver.driver.name,

				&client->dev, &s35390a_rtc_ops, THIS_MODULE);



	if (IS_ERR(s35390a->rtc)) {

		err = PTR_ERR(s35390a->rtc);

		goto exit_dummy;

	}

	return 0;



exit_dummy:

	for (i = 1; i < 8; ++i)

		if (s35390a->client[i])

			i2c_unregister_device(s35390a->client[i]);

	kfree(s35390a);

	i2c_set_clientdata(client, NULL);



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]);



	rtc_device_unregister(s35390a->rtc);

	kfree(s35390a);

	i2c_set_clientdata(client, NULL);



	return 0;

}



static struct i2c_driver s35390a_driver = {

	.driver		= {

		.name	= "rtc-s35390a",

	},

	.probe		= s35390a_probe,

	.remove		= s35390a_remove,

};



static int __init s35390a_rtc_init(void)

{

	return i2c_add_driver(&s35390a_driver);

}



static void __exit s35390a_rtc_exit(void)

{

	i2c_del_driver(&s35390a_driver);

}



MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>");

MODULE_DESCRIPTION("S35390A RTC driver");

MODULE_LICENSE("GPL");



module_init(s35390a_rtc_init);

module_exit(s35390a_rtc_exit);