Commit 9c0c5705 authored by G. Liakhovetski's avatar G. Liakhovetski Committed by Linus Torvalds
Browse files

[PATCH] drivers/acorn/char/pcf8583.[hc] vs. RTC subsystem 



A port of the driver for the pcf8583 i2c rtc controller to the generic RTC
framework by Alessandro Zummo.  Based on
drivers/acorn/char/{pcf8583.[hc],i2c.c}.  Hopefully, acorn can be converted
too to use this driver in the future.

Signed-off-by: default avatarG. Liakhovetski <gl@dsa-ac.de>
Signed-off-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 655066c3

drivers/rtc/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -132,6 +132,16 @@ config RTC_DRV_PCF8563 
	  This driver can also be built as a module. If so, the module

	  will be called rtc-pcf8563.



config RTC_DRV_PCF8583

	tristate "Philips PCF8583"

	depends on RTC_CLASS && I2C

	help

	  If you say yes here you get support for the

	  Philips PCF8583 RTC chip.



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

	  will be called rtc-pcf8583.



config RTC_DRV_RS5C372

	tristate "Ricoh RS5C372A/B"

	depends on RTC_CLASS && I2C

drivers/rtc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 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_PCF8563)	+= rtc-pcf8563.o

obj-$(CONFIG_RTC_DRV_PCF8583)	+= rtc-pcf8583.o

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

obj-$(CONFIG_RTC_DRV_M48T86)	+= rtc-m48t86.o

obj-$(CONFIG_RTC_DRV_EP93XX)	+= rtc-ep93xx.o

drivers/rtc/rtc-pcf8583.c

0 → 100644
+394 −0
Original line number Diff line number Diff line 
/*

 *  drivers/rtc/rtc-pcf8583.c

 *

 *  Copyright (C) 2000 Russell King

 *

 * 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.

 *

 *  Driver for PCF8583 RTC & RAM chip

 *

 *  Converted to the generic RTC susbsystem by G. Liakhovetski (2006)

 */

#include <linux/module.h>

#include <linux/i2c.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/mc146818rtc.h>

#include <linux/init.h>

#include <linux/errno.h>

#include <linux/bcd.h>



struct rtc_mem {

	unsigned int	loc;

	unsigned int	nr;

	unsigned char	*data;

};



struct pcf8583 {

	struct i2c_client client;

	struct rtc_device *rtc;

	unsigned char ctrl;

};



#define CTRL_STOP	0x80

#define CTRL_HOLD	0x40

#define CTRL_32KHZ	0x00

#define CTRL_MASK	0x08

#define CTRL_ALARMEN	0x04

#define CTRL_ALARM	0x02

#define CTRL_TIMER	0x01



static unsigned short normal_i2c[] = { I2C_CLIENT_END };



/* Module parameters */

I2C_CLIENT_INSMOD;



static struct i2c_driver pcf8583_driver;



#define get_ctrl(x)    ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl

#define set_ctrl(x, v) get_ctrl(x) = v



#define CMOS_YEAR	(64 + 128)

#define CMOS_CHECKSUM	(63)



static int pcf8583_get_datetime(struct i2c_client *client, struct rtc_time *dt)

{

	unsigned char buf[8], addr[1] = { 1 };

	struct i2c_msg msgs[2] = {

		{

			.addr = client->addr,

			.flags = 0,

			.len = 1,

			.buf = addr,

		}, {

			.addr = client->addr,

			.flags = I2C_M_RD,

			.len = 6,

			.buf = buf,

		}

	};

	int ret;



	memset(buf, 0, sizeof(buf));



	ret = i2c_transfer(client->adapter, msgs, 2);

	if (ret == 2) {

		dt->tm_year = buf[4] >> 6;

		dt->tm_wday = buf[5] >> 5;



		buf[4] &= 0x3f;

		buf[5] &= 0x1f;



		dt->tm_sec = BCD_TO_BIN(buf[1]);

		dt->tm_min = BCD_TO_BIN(buf[2]);

		dt->tm_hour = BCD_TO_BIN(buf[3]);

		dt->tm_mday = BCD_TO_BIN(buf[4]);

		dt->tm_mon = BCD_TO_BIN(buf[5]);

	}



	return ret == 2 ? 0 : -EIO;

}



static int pcf8583_set_datetime(struct i2c_client *client, struct rtc_time *dt, int datetoo)

{

	unsigned char buf[8];

	int ret, len = 6;



	buf[0] = 0;

	buf[1] = get_ctrl(client) | 0x80;

	buf[2] = 0;

	buf[3] = BIN_TO_BCD(dt->tm_sec);

	buf[4] = BIN_TO_BCD(dt->tm_min);

	buf[5] = BIN_TO_BCD(dt->tm_hour);



	if (datetoo) {

		len = 8;

		buf[6] = BIN_TO_BCD(dt->tm_mday) | (dt->tm_year << 6);

		buf[7] = BIN_TO_BCD(dt->tm_mon)  | (dt->tm_wday << 5);

	}



	ret = i2c_master_send(client, (char *)buf, len);

	if (ret != len)

		return -EIO;



	buf[1] = get_ctrl(client);

	ret = i2c_master_send(client, (char *)buf, 2);



	return ret == 2 ? 0 : -EIO;

}



static int pcf8583_get_ctrl(struct i2c_client *client, unsigned char *ctrl)

{

	*ctrl = get_ctrl(client);

	return 0;

}



static int pcf8583_set_ctrl(struct i2c_client *client, unsigned char *ctrl)

{

	unsigned char buf[2];



	buf[0] = 0;

	buf[1] = *ctrl;

	set_ctrl(client, *ctrl);



	return i2c_master_send(client, (char *)buf, 2);

}



static int pcf8583_read_mem(struct i2c_client *client, struct rtc_mem *mem)

{

	unsigned char addr[1];

	struct i2c_msg msgs[2] = {

		{

			.addr = client->addr,

			.flags = 0,

			.len = 1,

			.buf = addr,

		}, {

			.addr = client->addr,

			.flags = I2C_M_RD,

			.len = mem->nr,

			.buf = mem->data,

		}

	};



	if (mem->loc < 8)

		return -EINVAL;



	addr[0] = mem->loc;



	return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;

}



static int pcf8583_write_mem(struct i2c_client *client, struct rtc_mem *mem)

{

	unsigned char addr[1];

	struct i2c_msg msgs[2] = {

		{

			.addr = client->addr,

			.flags = 0,

			.len = 1,

			.buf = addr,

		}, {

			.addr = client->addr,

			.flags = I2C_M_NOSTART,

			.len = mem->nr,

			.buf = mem->data,

		}

	};



	if (mem->loc < 8)

		return -EINVAL;



	addr[0] = mem->loc;



	return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;

}



static int pcf8583_rtc_read_time(struct device *dev, struct rtc_time *tm)

{

	struct i2c_client *client = to_i2c_client(dev);

	unsigned char ctrl, year[2];

	struct rtc_mem mem = { CMOS_YEAR, sizeof(year), year };

	int real_year, year_offset, err;



	/*

	 * Ensure that the RTC is running.

	 */

	pcf8583_get_ctrl(client, &ctrl);

	if (ctrl & (CTRL_STOP | CTRL_HOLD)) {

		unsigned char new_ctrl = ctrl & ~(CTRL_STOP | CTRL_HOLD);



		printk(KERN_WARNING "RTC: resetting control %02x -> %02x\n",

		       ctrl, new_ctrl);



		if ((err = pcf8583_set_ctrl(client, &new_ctrl)) < 0)

			return err;

	}



	if (pcf8583_get_datetime(client, tm) ||

	    pcf8583_read_mem(client, &mem))

		return -EIO;



	real_year = year[0];



	/*

	 * The RTC year holds the LSB two bits of the current

	 * year, which should reflect the LSB two bits of the

	 * CMOS copy of the year.  Any difference indicates

	 * that we have to correct the CMOS version.

	 */

	year_offset = tm->tm_year - (real_year & 3);

	if (year_offset < 0)

		/*

		 * RTC year wrapped.  Adjust it appropriately.

		 */

		year_offset += 4;



	tm->tm_year = real_year + year_offset + year[1] * 100;



	return 0;

}



static int pcf8583_rtc_set_time(struct device *dev, struct rtc_time *tm)

{

	struct i2c_client *client = to_i2c_client(dev);

	unsigned char year[2], chk;

	struct rtc_mem cmos_year  = { CMOS_YEAR, sizeof(year), year };

	struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk };

	int ret;



	/*

	 * The RTC's own 2-bit year must reflect the least

	 * significant two bits of the CMOS year.

	 */



	ret = pcf8583_set_datetime(client, tm, 1);

	if (ret)

		return ret;



	ret = pcf8583_read_mem(client, &cmos_check);

	if (ret)

		return ret;



	ret = pcf8583_read_mem(client, &cmos_year);

	if (ret)

		return ret;



	chk -= year[1] + year[0];



	year[1] = tm->tm_year / 100;

	year[0] = tm->tm_year % 100;



	chk += year[1] + year[0];



	ret = pcf8583_write_mem(client, &cmos_year);



	if (ret)

		return ret;



	ret = pcf8583_write_mem(client, &cmos_check);



	return ret;

}



static struct rtc_class_ops pcf8583_rtc_ops = {

	.read_time	= pcf8583_rtc_read_time,

	.set_time	= pcf8583_rtc_set_time,

};



static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind);



static int pcf8583_attach(struct i2c_adapter *adap)

{

	return i2c_probe(adap, &addr_data, pcf8583_probe);

}



static int pcf8583_detach(struct i2c_client *client)

{

	int err;

	struct pcf8583 *pcf = i2c_get_clientdata(client);

	struct rtc_device *rtc = pcf->rtc;



	if (rtc)

		rtc_device_unregister(rtc);



	if ((err = i2c_detach_client(client)))

		return err;



	kfree(pcf);

	return 0;

}



static struct i2c_driver pcf8583_driver = {

	.driver = {

		.name	= "pcf8583",

	},

	.id		= I2C_DRIVERID_PCF8583,

	.attach_adapter	= pcf8583_attach,

	.detach_client	= pcf8583_detach,

};



static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind)

{

	struct pcf8583 *pcf;

	struct i2c_client *client;

	struct rtc_device *rtc;

	unsigned char buf[1], ad[1] = { 0 };

	int err;

	struct i2c_msg msgs[2] = {

		{

			.addr = addr,

			.flags = 0,

			.len = 1,

			.buf = ad,

		}, {

			.addr = addr,

			.flags = I2C_M_RD,

			.len = 1,

			.buf = buf,

		}

	};



	pcf = kzalloc(sizeof(*pcf), GFP_KERNEL);

	if (!pcf)

		return -ENOMEM;



	client = &pcf->client;



	client->addr		= addr;

	client->adapter	= adap;

	client->driver	= &pcf8583_driver;



	strlcpy(client->name, pcf8583_driver.driver.name, I2C_NAME_SIZE);



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

		err = -EIO;

		goto exit_kfree;

	}



	err = i2c_attach_client(client);



	if (err)

		goto exit_kfree;



	rtc = rtc_device_register(pcf8583_driver.driver.name, &client->dev,

				  &pcf8583_rtc_ops, THIS_MODULE);



	if (IS_ERR(rtc)) {

		err = PTR_ERR(rtc);

		goto exit_detach;

	}



	pcf->rtc = rtc;

	i2c_set_clientdata(client, pcf);

	set_ctrl(client, buf[0]);



	return 0;



exit_detach:

	i2c_detach_client(client);



exit_kfree:

	kfree(pcf);



	return err;

}



static __init int pcf8583_init(void)

{

	return i2c_add_driver(&pcf8583_driver);

}



static __exit void pcf8583_exit(void)

{

	i2c_del_driver(&pcf8583_driver);

}



module_init(pcf8583_init);

module_exit(pcf8583_exit);



MODULE_AUTHOR("Russell King");

MODULE_DESCRIPTION("PCF8583 I2C RTC driver");

MODULE_LICENSE("GPL");

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