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Commit 1fec7c66 authored by Alessandro Zummo's avatar Alessandro Zummo Committed by Linus Torvalds
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[PATCH] RTC subsystem: X1205 driver 

A port of the existing x1205 driver under the new RTC subsystem.

It is actually under test within the NSLU2 project
(http://www.nslu2-linux.org

) and it is working quite well.

It is the first driver under this new subsystem and should be used as a guide
to port other drivers.

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 e824290e

drivers/rtc/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -76,4 +76,14 @@ config RTC_INTF_DEV 
comment "RTC drivers"

	depends on RTC_CLASS



config RTC_DRV_X1205

	tristate "Xicor/Intersil X1205"

	depends on RTC_CLASS && I2C

	help

	  If you say yes here you get support for the

	  Xicor/Intersil X1205 RTC chip.



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

	  will be called rtc-x1205.



endmenu

drivers/rtc/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -10,3 +10,6 @@ rtc-core-y := class.o interface.o 
obj-$(CONFIG_RTC_INTF_SYSFS)	+= rtc-sysfs.o

obj-$(CONFIG_RTC_INTF_PROC)	+= rtc-proc.o

obj-$(CONFIG_RTC_INTF_DEV)	+= rtc-dev.o



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

drivers/rtc/rtc-x1205.c

0 → 100644
+619 −0
Original line number Diff line number Diff line 
/*

 * An i2c driver for the Xicor/Intersil X1205 RTC

 * Copyright 2004 Karen Spearel

 * Copyright 2005 Alessandro Zummo

 *

 * please send all reports to:

 * 	Karen Spearel <kas111 at gmail dot com>

 *	Alessandro Zummo <a.zummo@towertech.it>

 *

 * based on a lot of other RTC drivers.

 *

 * 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/i2c.h>

#include <linux/bcd.h>

#include <linux/rtc.h>

#include <linux/delay.h>



#define DRV_VERSION "1.0.6"



/* Addresses to scan: none. This chip is located at

 * 0x6f and uses a two bytes register addressing.

 * Two bytes need to be written to read a single register,

 * while most other chips just require one and take the second

 * one as the data to be written. To prevent corrupting

 * unknown chips, the user must explicitely set the probe parameter.

 */



static unsigned short normal_i2c[] = { I2C_CLIENT_END };



/* Insmod parameters */

I2C_CLIENT_INSMOD;



/* offsets into CCR area */



#define CCR_SEC			0

#define CCR_MIN			1

#define CCR_HOUR		2

#define CCR_MDAY		3

#define CCR_MONTH		4

#define CCR_YEAR		5

#define CCR_WDAY		6

#define CCR_Y2K			7



#define X1205_REG_SR		0x3F	/* status register */

#define X1205_REG_Y2K		0x37

#define X1205_REG_DW		0x36

#define X1205_REG_YR		0x35

#define X1205_REG_MO		0x34

#define X1205_REG_DT		0x33

#define X1205_REG_HR		0x32

#define X1205_REG_MN		0x31

#define X1205_REG_SC		0x30

#define X1205_REG_DTR		0x13

#define X1205_REG_ATR		0x12

#define X1205_REG_INT		0x11

#define X1205_REG_0		0x10

#define X1205_REG_Y2K1		0x0F

#define X1205_REG_DWA1		0x0E

#define X1205_REG_YRA1		0x0D

#define X1205_REG_MOA1		0x0C

#define X1205_REG_DTA1		0x0B

#define X1205_REG_HRA1		0x0A

#define X1205_REG_MNA1		0x09

#define X1205_REG_SCA1		0x08

#define X1205_REG_Y2K0		0x07

#define X1205_REG_DWA0		0x06

#define X1205_REG_YRA0		0x05

#define X1205_REG_MOA0		0x04

#define X1205_REG_DTA0		0x03

#define X1205_REG_HRA0		0x02

#define X1205_REG_MNA0		0x01

#define X1205_REG_SCA0		0x00



#define X1205_CCR_BASE		0x30	/* Base address of CCR */

#define X1205_ALM0_BASE		0x00	/* Base address of ALARM0 */



#define X1205_SR_RTCF		0x01	/* Clock failure */

#define X1205_SR_WEL		0x02	/* Write Enable Latch */

#define X1205_SR_RWEL		0x04	/* Register Write Enable */



#define X1205_DTR_DTR0		0x01

#define X1205_DTR_DTR1		0x02

#define X1205_DTR_DTR2		0x04



#define X1205_HR_MIL		0x80	/* Set in ccr.hour for 24 hr mode */



/* Prototypes */

static int x1205_attach(struct i2c_adapter *adapter);

static int x1205_detach(struct i2c_client *client);

static int x1205_probe(struct i2c_adapter *adapter, int address, int kind);



static struct i2c_driver x1205_driver = {

	.driver		= {

		.name	= "x1205",

	},

	.id		= I2C_DRIVERID_X1205,

	.attach_adapter = &x1205_attach,

	.detach_client	= &x1205_detach,

};



/*

 * In the routines that deal directly with the x1205 hardware, we use

 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch

 * Epoch is initialized as 2000. Time is set to UTC.

 */

static int x1205_get_datetime(struct i2c_client *client, struct rtc_time *tm,

				unsigned char reg_base)

{

	unsigned char dt_addr[2] = { 0, reg_base };



	unsigned char buf[8];



	struct i2c_msg msgs[] = {

		{ client->addr, 0, 2, dt_addr },	/* setup read ptr */

		{ client->addr, I2C_M_RD, 8, buf },	/* read date */

	};



	/* read date registers */

	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {

		dev_err(&client->dev, "%s: read error\n", __FUNCTION__);

		return -EIO;

	}



	dev_dbg(&client->dev,

		"%s: raw read data - sec=%02x, min=%02x, hr=%02x, "

		"mday=%02x, mon=%02x, year=%02x, wday=%02x, y2k=%02x\n",

		__FUNCTION__,

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

		buf[4], buf[5], buf[6], buf[7]);



	tm->tm_sec = BCD2BIN(buf[CCR_SEC]);

	tm->tm_min = BCD2BIN(buf[CCR_MIN]);

	tm->tm_hour = BCD2BIN(buf[CCR_HOUR] & 0x3F); /* hr is 0-23 */

	tm->tm_mday = BCD2BIN(buf[CCR_MDAY]);

	tm->tm_mon = BCD2BIN(buf[CCR_MONTH]) - 1; /* mon is 0-11 */

	tm->tm_year = BCD2BIN(buf[CCR_YEAR])

			+ (BCD2BIN(buf[CCR_Y2K]) * 100) - 1900;

	tm->tm_wday = buf[CCR_WDAY];



	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "

		"mday=%d, mon=%d, year=%d, wday=%d\n",

		__FUNCTION__,

		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 x1205_get_status(struct i2c_client *client, unsigned char *sr)

{

	static unsigned char sr_addr[2] = { 0, X1205_REG_SR };



	struct i2c_msg msgs[] = {

		{ client->addr, 0, 2, sr_addr },	/* setup read ptr */

		{ client->addr, I2C_M_RD, 1, sr },	/* read status */

	};



	/* read status register */

	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {

		dev_err(&client->dev, "%s: read error\n", __FUNCTION__);

		return -EIO;

	}



	return 0;

}



static int x1205_set_datetime(struct i2c_client *client, struct rtc_time *tm,

				int datetoo, u8 reg_base)

{

	int i, xfer;

	unsigned char buf[8];



	static const unsigned char wel[3] = { 0, X1205_REG_SR,

						X1205_SR_WEL };



	static const unsigned char rwel[3] = { 0, X1205_REG_SR,

						X1205_SR_WEL | X1205_SR_RWEL };



	static const unsigned char diswe[3] = { 0, X1205_REG_SR, 0 };



	dev_dbg(&client->dev,

		"%s: secs=%d, mins=%d, hours=%d\n",

		__FUNCTION__,

		tm->tm_sec, tm->tm_min, tm->tm_hour);



	buf[CCR_SEC] = BIN2BCD(tm->tm_sec);

	buf[CCR_MIN] = BIN2BCD(tm->tm_min);



	/* set hour and 24hr bit */

	buf[CCR_HOUR] = BIN2BCD(tm->tm_hour) | X1205_HR_MIL;



	/* should we also set the date? */

	if (datetoo) {

		dev_dbg(&client->dev,

			"%s: mday=%d, mon=%d, year=%d, wday=%d\n",

			__FUNCTION__,

			tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);



		buf[CCR_MDAY] = BIN2BCD(tm->tm_mday);



		/* month, 1 - 12 */

		buf[CCR_MONTH] = BIN2BCD(tm->tm_mon + 1);



		/* year, since the rtc epoch*/

		buf[CCR_YEAR] = BIN2BCD(tm->tm_year % 100);

		buf[CCR_WDAY] = tm->tm_wday & 0x07;

		buf[CCR_Y2K] = BIN2BCD(tm->tm_year / 100);

	}



	/* this sequence is required to unlock the chip */

	if ((xfer = i2c_master_send(client, wel, 3)) != 3) {

		dev_err(&client->dev, "%s: wel - %d\n", __FUNCTION__, xfer);

		return -EIO;

	}



	if ((xfer = i2c_master_send(client, rwel, 3)) != 3) {

		dev_err(&client->dev, "%s: rwel - %d\n", __FUNCTION__, xfer);

		return -EIO;

	}



	/* write register's data */

	for (i = 0; i < (datetoo ? 8 : 3); i++) {

		unsigned char rdata[3] = { 0, reg_base + i, buf[i] };



		xfer = i2c_master_send(client, rdata, 3);

		if (xfer != 3) {

			dev_err(&client->dev,

				"%s: xfer=%d addr=%02x, data=%02x\n",

				__FUNCTION__,

				 xfer, rdata[1], rdata[2]);

			return -EIO;

		}

	};



	/* disable further writes */

	if ((xfer = i2c_master_send(client, diswe, 3)) != 3) {

		dev_err(&client->dev, "%s: diswe - %d\n", __FUNCTION__, xfer);

		return -EIO;

	}



	return 0;

}



static int x1205_fix_osc(struct i2c_client *client)

{

	int err;

	struct rtc_time tm;



	tm.tm_hour = tm.tm_min = tm.tm_sec = 0;



	if ((err = x1205_set_datetime(client, &tm, 0, X1205_CCR_BASE)) < 0)

		dev_err(&client->dev,

			"unable to restart the oscillator\n");



	return err;

}



static int x1205_get_dtrim(struct i2c_client *client, int *trim)

{

	unsigned char dtr;

	static unsigned char dtr_addr[2] = { 0, X1205_REG_DTR };



	struct i2c_msg msgs[] = {

		{ client->addr, 0, 2, dtr_addr },	/* setup read ptr */

		{ client->addr, I2C_M_RD, 1, &dtr }, 	/* read dtr */

	};



	/* read dtr register */

	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {

		dev_err(&client->dev, "%s: read error\n", __FUNCTION__);

		return -EIO;

	}



	dev_dbg(&client->dev, "%s: raw dtr=%x\n", __FUNCTION__, dtr);



	*trim = 0;



	if (dtr & X1205_DTR_DTR0)

		*trim += 20;



	if (dtr & X1205_DTR_DTR1)

		*trim += 10;



	if (dtr & X1205_DTR_DTR2)

		*trim = -*trim;



	return 0;

}



static int x1205_get_atrim(struct i2c_client *client, int *trim)

{

	s8 atr;

	static unsigned char atr_addr[2] = { 0, X1205_REG_ATR };



	struct i2c_msg msgs[] = {

		{ client->addr, 0, 2, atr_addr },	/* setup read ptr */

		{ client->addr, I2C_M_RD, 1, &atr }, 	/* read atr */

	};



	/* read atr register */

	if ((i2c_transfer(client->adapter, &msgs[0], 2)) != 2) {

		dev_err(&client->dev, "%s: read error\n", __FUNCTION__);

		return -EIO;

	}



	dev_dbg(&client->dev, "%s: raw atr=%x\n", __FUNCTION__, atr);



	/* atr is a two's complement value on 6 bits,

	 * perform sign extension. The formula is

	 * Catr = (atr * 0.25pF) + 11.00pF.

	 */

	if (atr & 0x20)

		atr |= 0xC0;



	dev_dbg(&client->dev, "%s: raw atr=%x (%d)\n", __FUNCTION__, atr, atr);



	*trim = (atr * 250) + 11000;



	dev_dbg(&client->dev, "%s: real=%d\n", __FUNCTION__, *trim);



	return 0;

}



struct x1205_limit

{

	unsigned char reg, mask, min, max;

};



static int x1205_validate_client(struct i2c_client *client)

{

	int i, xfer;



	/* Probe array. We will read the register at the specified

	 * address and check if the given bits are zero.

	 */

	static const unsigned char probe_zero_pattern[] = {

		/* register, mask */

		X1205_REG_SR,	0x18,

		X1205_REG_DTR,	0xF8,

		X1205_REG_ATR,	0xC0,

		X1205_REG_INT,	0x18,

		X1205_REG_0,	0xFF,

	};



	static const struct x1205_limit probe_limits_pattern[] = {

		/* register, mask, min, max */

		{ X1205_REG_Y2K,	0xFF,	19,	20	},

		{ X1205_REG_DW,		0xFF,	0,	6	},

		{ X1205_REG_YR,		0xFF,	0,	99	},

		{ X1205_REG_MO,		0xFF,	0,	12	},

		{ X1205_REG_DT,		0xFF,	0,	31	},

		{ X1205_REG_HR,		0x7F,	0,	23	},

		{ X1205_REG_MN,		0xFF,	0,	59	},

		{ X1205_REG_SC,		0xFF,	0,	59	},

		{ X1205_REG_Y2K1,	0xFF,	19,	20	},

		{ X1205_REG_Y2K0,	0xFF,	19,	20	},

	};



	/* check that registers have bits a 0 where expected */

	for (i = 0; i < ARRAY_SIZE(probe_zero_pattern); i += 2) {

		unsigned char buf;



		unsigned char addr[2] = { 0, probe_zero_pattern[i] };



		struct i2c_msg msgs[2] = {

			{ client->addr, 0, 2, addr },

			{ client->addr, I2C_M_RD, 1, &buf },

		};



		if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {

			dev_err(&client->adapter->dev,

				"%s: could not read register %x\n",

				__FUNCTION__, probe_zero_pattern[i]);



			return -EIO;

		}



		if ((buf & probe_zero_pattern[i+1]) != 0) {

			dev_err(&client->adapter->dev,

				"%s: register=%02x, zero pattern=%d, value=%x\n",

				__FUNCTION__, probe_zero_pattern[i], i, buf);



			return -ENODEV;

		}

	}



	/* check limits (only registers with bcd values) */

	for (i = 0; i < ARRAY_SIZE(probe_limits_pattern); i++) {

		unsigned char reg, value;



		unsigned char addr[2] = { 0, probe_limits_pattern[i].reg };



		struct i2c_msg msgs[2] = {

			{ client->addr, 0, 2, addr },

			{ client->addr, I2C_M_RD, 1, &reg },

		};



		if ((xfer = i2c_transfer(client->adapter, msgs, 2)) != 2) {

			dev_err(&client->adapter->dev,

				"%s: could not read register %x\n",

				__FUNCTION__, probe_limits_pattern[i].reg);



			return -EIO;

		}



		value = BCD2BIN(reg & probe_limits_pattern[i].mask);



		if (value > probe_limits_pattern[i].max ||

			value < probe_limits_pattern[i].min) {

			dev_dbg(&client->adapter->dev,

				"%s: register=%x, lim pattern=%d, value=%d\n",

				__FUNCTION__, probe_limits_pattern[i].reg,

				i, value);



			return -ENODEV;

		}

	}



	return 0;

}



static int x1205_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)

{

	return x1205_get_datetime(to_i2c_client(dev),

		&alrm->time, X1205_ALM0_BASE);

}



static int x1205_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)

{

	return x1205_set_datetime(to_i2c_client(dev),

		&alrm->time, 1, X1205_ALM0_BASE);

}



static int x1205_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	return x1205_get_datetime(to_i2c_client(dev),

		tm, X1205_CCR_BASE);

}



static int x1205_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	return x1205_set_datetime(to_i2c_client(dev),

		tm, 1, X1205_CCR_BASE);

}



static int x1205_rtc_proc(struct device *dev, struct seq_file *seq)

{

	int err, dtrim, atrim;



	seq_printf(seq, "24hr\t\t: yes\n");



	if ((err = x1205_get_dtrim(to_i2c_client(dev), &dtrim)) == 0)

		seq_printf(seq, "digital_trim\t: %d ppm\n", dtrim);



	if ((err = x1205_get_atrim(to_i2c_client(dev), &atrim)) == 0)

		seq_printf(seq, "analog_trim\t: %d.%02d pF\n",

			atrim / 1000, atrim % 1000);

	return 0;

}



static struct rtc_class_ops x1205_rtc_ops = {

	.proc		= x1205_rtc_proc,

	.read_time	= x1205_rtc_read_time,

	.set_time	= x1205_rtc_set_time,

	.read_alarm	= x1205_rtc_read_alarm,

	.set_alarm	= x1205_rtc_set_alarm,

};



static ssize_t x1205_sysfs_show_atrim(struct device *dev,

				struct device_attribute *attr, char *buf)

{

	int atrim;



	if (x1205_get_atrim(to_i2c_client(dev), &atrim) == 0)

		return sprintf(buf, "%d.%02d pF\n",

			atrim / 1000, atrim % 1000);

	return 0;

}

static DEVICE_ATTR(atrim, S_IRUGO, x1205_sysfs_show_atrim, NULL);



static ssize_t x1205_sysfs_show_dtrim(struct device *dev,

				struct device_attribute *attr, char *buf)

{

	int dtrim;



	if (x1205_get_dtrim(to_i2c_client(dev), &dtrim) == 0)

		return sprintf(buf, "%d ppm\n", dtrim);



	return 0;

}

static DEVICE_ATTR(dtrim, S_IRUGO, x1205_sysfs_show_dtrim, NULL);



static int x1205_attach(struct i2c_adapter *adapter)

{

	dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);

	return i2c_probe(adapter, &addr_data, x1205_probe);

}



static int x1205_probe(struct i2c_adapter *adapter, int address, int kind)

{

	int err = 0;

	unsigned char sr;

	struct i2c_client *client;

	struct rtc_device *rtc;



	dev_dbg(&adapter->dev, "%s\n", __FUNCTION__);



	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {

		err = -ENODEV;

		goto exit;

	}



	if (!(client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL))) {

		err = -ENOMEM;

		goto exit;

	}



	/* I2C client */

	client->addr = address;

	client->driver = &x1205_driver;

	client->adapter	= adapter;



	strlcpy(client->name, x1205_driver.driver.name, I2C_NAME_SIZE);



	/* Verify the chip is really an X1205 */

	if (kind < 0) {

		if (x1205_validate_client(client) < 0) {

			err = -ENODEV;

			goto exit_kfree;

		}

	}



	/* Inform the i2c layer */

	if ((err = i2c_attach_client(client)))

		goto exit_kfree;



	dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");



	rtc = rtc_device_register(x1205_driver.driver.name, &client->dev,

				&x1205_rtc_ops, THIS_MODULE);



	if (IS_ERR(rtc)) {

		err = PTR_ERR(rtc);

		dev_err(&client->dev,

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

		goto exit_detach;

	}



	i2c_set_clientdata(client, rtc);



	/* Check for power failures and eventualy enable the osc */

	if ((err = x1205_get_status(client, &sr)) == 0) {

		if (sr & X1205_SR_RTCF) {

			dev_err(&client->dev,

				"power failure detected, "

				"please set the clock\n");

			udelay(50);

			x1205_fix_osc(client);

		}

	}

	else

		dev_err(&client->dev, "couldn't read status\n");



	device_create_file(&client->dev, &dev_attr_atrim);

	device_create_file(&client->dev, &dev_attr_dtrim);



	return 0;



exit_detach:

	i2c_detach_client(client);



exit_kfree:

	kfree(client);



exit:

	return err;

}



static int x1205_detach(struct i2c_client *client)

{

	int err;

	struct rtc_device *rtc = i2c_get_clientdata(client);



	dev_dbg(&client->dev, "%s\n", __FUNCTION__);



 	if (rtc)

		rtc_device_unregister(rtc);



	if ((err = i2c_detach_client(client)))

		return err;



	kfree(client);



	return 0;

}



static int __init x1205_init(void)

{

	return i2c_add_driver(&x1205_driver);

}



static void __exit x1205_exit(void)

{

	i2c_del_driver(&x1205_driver);

}



MODULE_AUTHOR(

	"Karen Spearel <kas111 at gmail dot com>, "

	"Alessandro Zummo <a.zummo@towertech.it>");

MODULE_DESCRIPTION("Xicor/Intersil X1205 RTC driver");

MODULE_LICENSE("GPL");

MODULE_VERSION(DRV_VERSION);



module_init(x1205_init);

module_exit(x1205_exit);