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Commit 1abb0dc9 authored by David Brownell's avatar David Brownell Committed by Linus Torvalds
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[PATCH] "RTC-framework" driver for DS1307 and similar RTC chips 



This is an "RTC-framework" driver for DS1307 and similar RTC chips,

It should be a full replacement for the existing ds1337.c driver (using the
older RTC glue), giving a net increase in the number of RTC chips that work
out-of-the-box.  There's a whole cluster of RTCs that are very similar, but
the 1337 driver was a bit too picky to work with most of them.

Still no support for RTC alarm IRQs (on chips that support them).

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarJames Chapman <jchapman@katalix.com>
Signed-off-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 3eecd1dc

drivers/rtc/Kconfig

+18 −0
Original line number Original line Diff line number Diff line
@@ -86,6 +86,24 @@ config RTC_DRV_X1205 
	  This driver can also be built as a module. If so, the module

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

	  will be called rtc-x1205.

	  will be called rtc-x1205.





config RTC_DRV_DS1307

	tristate "Dallas/Maxim DS1307 and similar I2C RTC chips"

	depends on RTC_CLASS && I2C

	help

	  If you say yes here you get support for various compatible RTC

	  chips (often with battery backup) connected with I2C.  This driver

	  should handle DS1307, DS1337, DS1338, DS1339, DS1340, ST M41T00,

	  and probably other chips.  In some cases the RTC must already

	  have been initialized (by manufacturing or a bootloader).



	  The first seven registers on these chips hold an RTC, and other

	  registers may add features such as NVRAM, a trickle charger for

	  the RTC/NVRAM backup power, and alarms.  This driver may not

	  expose all those available chip features.



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

	  will be called rtc-ds1307.



config RTC_DRV_DS1672

config RTC_DRV_DS1672

	tristate "Dallas/Maxim DS1672"

	tristate "Dallas/Maxim DS1672"

	depends on RTC_CLASS && I2C

	depends on RTC_CLASS && I2C

drivers/rtc/Makefile

+1 −0
Original line number Original line Diff line number Diff line
@@ -13,6 +13,7 @@ obj-$(CONFIG_RTC_INTF_DEV) += rtc-dev.o 




obj-$(CONFIG_RTC_DRV_X1205)	+= rtc-x1205.o

obj-$(CONFIG_RTC_DRV_X1205)	+= rtc-x1205.o

obj-$(CONFIG_RTC_DRV_TEST)	+= rtc-test.o

obj-$(CONFIG_RTC_DRV_TEST)	+= rtc-test.o

obj-$(CONFIG_RTC_DRV_DS1307)	+= rtc-ds1307.o

obj-$(CONFIG_RTC_DRV_DS1672)	+= rtc-ds1672.o

obj-$(CONFIG_RTC_DRV_DS1672)	+= rtc-ds1672.o

obj-$(CONFIG_RTC_DRV_PCF8563)	+= rtc-pcf8563.o

obj-$(CONFIG_RTC_DRV_PCF8563)	+= rtc-pcf8563.o

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

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

drivers/rtc/rtc-ds1307.c

0 → 100644
+388 −0
Original line number Original line Diff line number Diff line 
/*

 * rtc-ds1307.c - RTC driver for some mostly-compatible I2C chips.

 *

 *  Copyright (C) 2005 James Chapman (ds1337 core)

 *  Copyright (C) 2006 David Brownell

 *

 * 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>







/* 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.

 *

 * If the I2C "force" mechanism is used, we assume the chip is a ds1337.

 * (Much better would be board-specific tables of I2C devices, along with

 * the platform_data drivers would use to sort such issues out.)

 */

enum ds_type {

	unknown = 0,

	ds_1307,		/* or ds1338, ... */

	ds_1337,		/* or ds1339, ... */

	ds_1340,		/* or st m41t00, ... */

	// rs5c372 too?  different address...

};



static unsigned short normal_i2c[] = { 0x68, I2C_CLIENT_END };



I2C_CLIENT_INSMOD;







/* RTC registers don't differ much, except for the century flag */

#define DS1307_REG_SECS		0x00	/* 00-59 */

#	define DS1307_BIT_CH		0x80

#define DS1307_REG_MIN		0x01	/* 00-59 */

#define DS1307_REG_HOUR		0x02	/* 00-23, or 1-12{am,pm} */

#	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 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 RTC;

 * be careful using them.

 */

#define DS1307_REG_CONTROL	0x07

#	define DS1307_BIT_OUT		0x80

#	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 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 DS1337_REG_STATUS	0x0f

#	define DS1337_BIT_OSF		0x80

#	define DS1337_BIT_A2I		0x02

#	define DS1337_BIT_A1I		0x01

#define DS1339_REG_TRICKLE	0x10







struct ds1307 {

	u8			reg_addr;

	u8			regs[8];

	enum ds_type		type;

	struct i2c_msg		msg[2];

	struct i2c_client	client;

	struct rtc_device	*rtc;

};





static int ds1307_get_time(struct device *dev, struct rtc_time *t)

{

	struct ds1307	*ds1307 = dev_get_drvdata(dev);

	int		tmp;



	/* read the RTC registers all at once */

	ds1307->msg[1].flags = I2C_M_RD;

	ds1307->msg[1].len = 7;



	tmp = i2c_transfer(ds1307->client.adapter, ds1307->msg, 2);

	if (tmp != 2) {

		dev_err(dev, "%s error %d\n", "read", tmp);

		return -EIO;

	}



	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",

			"read",

			ds1307->regs[0], ds1307->regs[1],

			ds1307->regs[2], ds1307->regs[3],

			ds1307->regs[4], ds1307->regs[5],

			ds1307->regs[6]);



	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);



	return 0;

}



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", dt->tm_sec, dt->tm_min,

		dt->tm_hour, dt->tm_mday,

		dt->tm_mon, dt->tm_year, dt->tm_wday);



	*buf++ = 0;		/* first register addr */

	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);



	if (ds1307->type == ds_1337)

		buf[DS1307_REG_MONTH] |= DS1337_BIT_CENTURY;

	else if (ds1307->type == ds_1340)

		buf[DS1307_REG_HOUR] |= DS1340_BIT_CENTURY_EN

				| DS1340_BIT_CENTURY;



	ds1307->msg[1].flags = 0;

	ds1307->msg[1].len = 8;



	dev_dbg(dev, "%s: %02x %02x %02x %02x %02x %02x %02x\n",

		"write", buf[0], buf[1], buf[2], buf[3],

		buf[4], buf[5], buf[6]);



	result = i2c_transfer(ds1307->client.adapter, &ds1307->msg[1], 1);

	if (result != 1) {

		dev_err(dev, "%s error %d\n", "write", tmp);

		return -EIO;

	}

	return 0;

}



static struct rtc_class_ops ds13xx_rtc_ops = {

	.read_time	= ds1307_get_time,

	.set_time	= ds1307_set_time,

};



static struct i2c_driver ds1307_driver;



static int __devinit

ds1307_detect(struct i2c_adapter *adapter, int address, int kind)

{

	struct ds1307		*ds1307;

	int			err = -ENODEV;

	struct i2c_client	*client;

	int			tmp;



	if (!(ds1307 = kzalloc(sizeof(struct ds1307), GFP_KERNEL))) {

		err = -ENOMEM;

		goto exit;

	}



	client = &ds1307->client;

	client->addr = address;

	client->adapter = adapter;

	client->driver = &ds1307_driver;

	client->flags = 0;



	i2c_set_clientdata(client, ds1307);



	ds1307->msg[0].addr = client->addr;

	ds1307->msg[0].flags = 0;

	ds1307->msg[0].len = 1;

	ds1307->msg[0].buf = &ds1307->reg_addr;



	ds1307->msg[1].addr = client->addr;

	ds1307->msg[1].flags = I2C_M_RD;

	ds1307->msg[1].len = sizeof(ds1307->regs);

	ds1307->msg[1].buf = ds1307->regs;



	/* HACK: "force" implies "needs ds1337-style-oscillator setup" */

	if (kind >= 0) {

		ds1307->type = ds_1337;



		ds1307->reg_addr = DS1337_REG_CONTROL;

		ds1307->msg[1].len = 2;



		tmp = i2c_transfer(client->adapter, ds1307->msg, 2);

		if (tmp != 2) {

			pr_debug("read error %d\n", tmp);

			err = -EIO;

			goto exit_free;

		}



		ds1307->reg_addr = 0;

		ds1307->msg[1].len = sizeof(ds1307->regs);



		/* oscillator is off; need to turn it on */

		if ((ds1307->regs[0] & DS1337_BIT_nEOSC)

				|| (ds1307->regs[1] & DS1337_BIT_OSF)) {

			printk(KERN_ERR "no ds1337 oscillator code\n");

			goto exit_free;

		}

	} else

		ds1307->type = ds_1307;



read_rtc:

	/* read RTC registers */



	tmp = i2c_transfer(client->adapter, ds1307->msg, 2);

	if (tmp != 2) {

		pr_debug("read error %d\n", tmp);

		err = -EIO;

		goto exit_free;

	}



	/* 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];

	if (tmp & DS1307_BIT_CH) {

		if (ds1307->type && ds1307->type != ds_1307) {

			pr_debug("not a ds1307?\n");

			goto exit_free;

		}

		ds1307->type = ds_1307;



		/* this partial initialization should work for ds1307,

		 * ds1338, ds1340, st m41t00, and more.

		 */

		dev_warn(&client->dev, "oscillator started; SET TIME!\n");

		i2c_smbus_write_byte_data(client, 0, 0);

		goto read_rtc;

	}

	tmp = BCD2BIN(tmp & 0x7f);

	if (tmp > 60)

		goto exit_free;

	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MIN] & 0x7f);

	if (tmp > 60)

		goto exit_free;



	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MDAY] & 0x3f);

	if (tmp == 0 || tmp > 31)

		goto exit_free;



	tmp = BCD2BIN(ds1307->regs[DS1307_REG_MONTH] & 0x1f);

	if (tmp == 0 || tmp > 12)

		goto exit_free;



	/* force into in 24 hour mode (most chips) or

	 * disable century bit (ds1340)

	 */

	tmp = ds1307->regs[DS1307_REG_HOUR];

	if (tmp & (1 << 6)) {

		if (tmp & (1 << 5))

			tmp = BCD2BIN(tmp & 0x1f) + 12;

		else

			tmp = BCD2BIN(tmp);

		i2c_smbus_write_byte_data(client,

				DS1307_REG_HOUR,

				BIN2BCD(tmp));

	}



	/* FIXME chips like 1337 can generate alarm irqs too; those are

	 * worth exposing through the API (especially when the irq is

	 * wakeup-capable).

	 */



	switch (ds1307->type) {

	case unknown:

		strlcpy(client->name, "unknown", I2C_NAME_SIZE);

		break;

	case ds_1307:

		strlcpy(client->name, "ds1307", I2C_NAME_SIZE);

		break;

	case ds_1337:

		strlcpy(client->name, "ds1337", I2C_NAME_SIZE);

		break;

	case ds_1340:

		strlcpy(client->name, "ds1340", I2C_NAME_SIZE);

		break;

	}



	/* Tell the I2C layer a new client has arrived */

	if ((err = i2c_attach_client(client)))

		goto exit_free;



	ds1307->rtc = rtc_device_register(client->name, &client->dev,

				&ds13xx_rtc_ops, THIS_MODULE);

	if (IS_ERR(ds1307->rtc)) {

		err = PTR_ERR(ds1307->rtc);

		dev_err(&client->dev,

			"unable to register the class device\n");

		goto exit_detach;

	}



	return 0;



exit_detach:

	i2c_detach_client(client);

exit_free:

	kfree(ds1307);

exit:

	return err;

}



static int __devinit

ds1307_attach_adapter(struct i2c_adapter *adapter)

{

	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C))

		return 0;

	return i2c_probe(adapter, &addr_data, ds1307_detect);

}



static int __devexit ds1307_detach_client(struct i2c_client *client)

{

	int		err;

	struct ds1307	*ds1307 = i2c_get_clientdata(client);



	rtc_device_unregister(ds1307->rtc);

	if ((err = i2c_detach_client(client)))

		return err;

	kfree(ds1307);

	return 0;

}



static struct i2c_driver ds1307_driver = {

	.driver = {

		.name	= "ds1307",

		.owner	= THIS_MODULE,

	},

	.attach_adapter	= ds1307_attach_adapter,

	.detach_client	= __devexit_p(ds1307_detach_client),

};



static int __init ds1307_init(void)

{

	return i2c_add_driver(&ds1307_driver);

}

module_init(ds1307_init);



static void __exit ds1307_exit(void)

{

	i2c_del_driver(&ds1307_driver);

}

module_exit(ds1307_exit);



MODULE_DESCRIPTION("RTC driver for DS1307 and similar chips");

MODULE_LICENSE("GPL");