[mirror_ubuntu-bionic-kernel.git] / drivers / rtc / rtc-pcf8583.c

/*
 *  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 const unsigned short normal_i2c[] = { 0x50, 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 = BCD2BIN(buf[1]);
		dt->tm_min = BCD2BIN(buf[2]);
		dt->tm_hour = BCD2BIN(buf[3]);
		dt->tm_mday = BCD2BIN(buf[4]);
		dt->tm_mon = BCD2BIN(buf[5]) - 1;
	}

	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] = BIN2BCD(dt->tm_sec);
	buf[4] = BIN2BCD(dt->tm_min);
	buf[5] = BIN2BCD(dt->tm_hour);

	if (datetoo) {
		len = 8;
		buf[6] = BIN2BCD(dt->tm_mday) | (dt->tm_year << 6);
		buf[7] = BIN2BCD(dt->tm_mon + 1)  | (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) - 1900;

	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 };
	unsigned int proper_year = tm->tm_year + 1900;
	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] = proper_year / 100;
	year[0] = proper_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 const 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,
		}
	};

	if (!i2c_check_functionality(adap, I2C_FUNC_I2C))
		return 0;

	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");
Commit	Line	Data
9c0c5705 L	1	/*
	2	* drivers/rtc/rtc-pcf8583.c
	3	*
	4	* Copyright (C) 2000 Russell King
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* Driver for PCF8583 RTC & RAM chip
	11	*
	12	* Converted to the generic RTC susbsystem by G. Liakhovetski (2006)
	13	*/
	14	#include <linux/module.h>
	15	#include <linux/i2c.h>
	16	#include <linux/slab.h>
	17	#include <linux/string.h>
	18	#include <linux/mc146818rtc.h>
	19	#include <linux/init.h>
	20	#include <linux/errno.h>
	21	#include <linux/bcd.h>
	22
	23	struct rtc_mem {
	24	unsigned int loc;
	25	unsigned int nr;
	26	unsigned char *data;
	27	};
	28
	29	struct pcf8583 {
	30	struct i2c_client client;
	31	struct rtc_device *rtc;
	32	unsigned char ctrl;
	33	};
	34
	35	#define CTRL_STOP 0x80
	36	#define CTRL_HOLD 0x40
	37	#define CTRL_32KHZ 0x00
	38	#define CTRL_MASK 0x08
	39	#define CTRL_ALARMEN 0x04
	40	#define CTRL_ALARM 0x02
	41	#define CTRL_TIMER 0x01
	42
922539a0	43	static const unsigned short normal_i2c[] = { 0x50, I2C_CLIENT_END };
9c0c5705 L	44
	45	/* Module parameters */
	46	I2C_CLIENT_INSMOD;
	47
	48	static struct i2c_driver pcf8583_driver;
	49
	50	#define get_ctrl(x) ((struct pcf8583 *)i2c_get_clientdata(x))->ctrl
	51	#define set_ctrl(x, v) get_ctrl(x) = v
	52
	53	#define CMOS_YEAR (64 + 128)
	54	#define CMOS_CHECKSUM (63)
	55
	56	static int pcf8583_get_datetime(struct i2c_client client, struct rtc_time dt)
	57	{
	58	unsigned char buf[8], addr[1] = { 1 };
	59	struct i2c_msg msgs[2] = {
	60	{
	61	.addr = client->addr,
	62	.flags = 0,
	63	.len = 1,
	64	.buf = addr,
	65	}, {
	66	.addr = client->addr,
	67	.flags = I2C_M_RD,
	68	.len = 6,
	69	.buf = buf,
	70	}
	71	};
	72	int ret;
	73
	74	memset(buf, 0, sizeof(buf));
	75
	76	ret = i2c_transfer(client->adapter, msgs, 2);
	77	if (ret == 2) {
	78	dt->tm_year = buf[4] >> 6;
	79	dt->tm_wday = buf[5] >> 5;
	80
	81	buf[4] &= 0x3f;
	82	buf[5] &= 0x1f;
	83
f5e5b734 RK	84	dt->tm_sec = BCD2BIN(buf[1]);
	85	dt->tm_min = BCD2BIN(buf[2]);
	86	dt->tm_hour = BCD2BIN(buf[3]);
	87	dt->tm_mday = BCD2BIN(buf[4]);
0ed8f210	88	dt->tm_mon = BCD2BIN(buf[5]) - 1;
9c0c5705 L	89	}
	90
	91	return ret == 2 ? 0 : -EIO;
	92	}
	93
	94	static int pcf8583_set_datetime(struct i2c_client client, struct rtc_time dt, int datetoo)
	95	{
	96	unsigned char buf[8];
	97	int ret, len = 6;
	98
	99	buf[0] = 0;
	100	buf[1] = get_ctrl(client) \| 0x80;
	101	buf[2] = 0;
f5e5b734 RK	102	buf[3] = BIN2BCD(dt->tm_sec);
	103	buf[4] = BIN2BCD(dt->tm_min);
	104	buf[5] = BIN2BCD(dt->tm_hour);
9c0c5705 L	105
	106	if (datetoo) {
	107	len = 8;
f5e5b734	108	buf[6] = BIN2BCD(dt->tm_mday) \| (dt->tm_year << 6);
0ed8f210	109	buf[7] = BIN2BCD(dt->tm_mon + 1) \| (dt->tm_wday << 5);
9c0c5705 L	110	}
	111
	112	ret = i2c_master_send(client, (char *)buf, len);
	113	if (ret != len)
	114	return -EIO;
	115
	116	buf[1] = get_ctrl(client);
	117	ret = i2c_master_send(client, (char *)buf, 2);
	118
	119	return ret == 2 ? 0 : -EIO;
	120	}
	121
	122	static int pcf8583_get_ctrl(struct i2c_client client, unsigned char ctrl)
	123	{
	124	*ctrl = get_ctrl(client);
	125	return 0;
	126	}
	127
	128	static int pcf8583_set_ctrl(struct i2c_client client, unsigned char ctrl)
	129	{
	130	unsigned char buf[2];
	131
	132	buf[0] = 0;
	133	buf[1] = *ctrl;
	134	set_ctrl(client, *ctrl);
	135
	136	return i2c_master_send(client, (char *)buf, 2);
	137	}
	138
	139	static int pcf8583_read_mem(struct i2c_client client, struct rtc_mem mem)
	140	{
	141	unsigned char addr[1];
	142	struct i2c_msg msgs[2] = {
	143	{
	144	.addr = client->addr,
	145	.flags = 0,
	146	.len = 1,
	147	.buf = addr,
	148	}, {
	149	.addr = client->addr,
	150	.flags = I2C_M_RD,
	151	.len = mem->nr,
	152	.buf = mem->data,
	153	}
	154	};
	155
	156	if (mem->loc < 8)
	157	return -EINVAL;
	158
	159	addr[0] = mem->loc;
	160
	161	return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
	162	}
	163
	164	static int pcf8583_write_mem(struct i2c_client client, struct rtc_mem mem)
	165	{
	166	unsigned char addr[1];
	167	struct i2c_msg msgs[2] = {
	168	{
	169	.addr = client->addr,
	170	.flags = 0,
	171	.len = 1,
	172	.buf = addr,
	173	}, {
174	.addr = client->addr,
175	.flags = I2C_M_NOSTART,
176	.len = mem->nr,
177	.buf = mem->data,
178	}
179	};
180
181	if (mem->loc < 8)
182	return -EINVAL;
183
184	addr[0] = mem->loc;
185
186	return i2c_transfer(client->adapter, msgs, 2) == 2 ? 0 : -EIO;
187	}
188
189	static int pcf8583_rtc_read_time(struct device dev, struct rtc_time tm)
190	{
191	struct i2c_client *client = to_i2c_client(dev);
192	unsigned char ctrl, year[2];
193	struct rtc_mem mem = { CMOS_YEAR, sizeof(year), year };
194	int real_year, year_offset, err;
195
196	/*
197	* Ensure that the RTC is running.
198	*/
199	pcf8583_get_ctrl(client, &ctrl);
200	if (ctrl & (CTRL_STOP \| CTRL_HOLD)) {
201	unsigned char new_ctrl = ctrl & ~(CTRL_STOP \| CTRL_HOLD);
202
203	printk(KERN_WARNING "RTC: resetting control %02x -> %02x\n",
204	ctrl, new_ctrl);
205
206	if ((err = pcf8583_set_ctrl(client, &new_ctrl)) < 0)
207	return err;
208	}
209
210	if (pcf8583_get_datetime(client, tm) \|\|
211	pcf8583_read_mem(client, &mem))
212	return -EIO;
213
214	real_year = year[0];
215
216	/*
217	* The RTC year holds the LSB two bits of the current
218	* year, which should reflect the LSB two bits of the
219	* CMOS copy of the year. Any difference indicates
220	* that we have to correct the CMOS version.
221	*/
222	year_offset = tm->tm_year - (real_year & 3);
223	if (year_offset < 0)
224	/*
225	* RTC year wrapped. Adjust it appropriately.
226	*/
227	year_offset += 4;
228
0ed8f210	229	tm->tm_year = (real_year + year_offset + year[1] * 100) - 1900;
9c0c5705 L	230
	231	return 0;
	232	}
	233
	234	static int pcf8583_rtc_set_time(struct device dev, struct rtc_time tm)
	235	{
	236	struct i2c_client *client = to_i2c_client(dev);
	237	unsigned char year[2], chk;
	238	struct rtc_mem cmos_year = { CMOS_YEAR, sizeof(year), year };
	239	struct rtc_mem cmos_check = { CMOS_CHECKSUM, 1, &chk };
0ed8f210	240	unsigned int proper_year = tm->tm_year + 1900;
9c0c5705 L	241	int ret;
	242
	243	/*
	244	* The RTC's own 2-bit year must reflect the least
	245	* significant two bits of the CMOS year.
	246	*/
	247
	248	ret = pcf8583_set_datetime(client, tm, 1);
	249	if (ret)
	250	return ret;
	251
	252	ret = pcf8583_read_mem(client, &cmos_check);
	253	if (ret)
	254	return ret;
	255
	256	ret = pcf8583_read_mem(client, &cmos_year);
	257	if (ret)
	258	return ret;
	259
	260	chk -= year[1] + year[0];
	261
0ed8f210 RK	262	year[1] = proper_year / 100;
0ed8f210 RK	263	year[0] = proper_year % 100;
9c0c5705 L	264
	265	chk += year[1] + year[0];
	266
	267	ret = pcf8583_write_mem(client, &cmos_year);
	268
	269	if (ret)
	270	return ret;
	271
	272	ret = pcf8583_write_mem(client, &cmos_check);
	273
	274	return ret;
	275	}
	276
ff8371ac	277	static const struct rtc_class_ops pcf8583_rtc_ops = {
9c0c5705 L	278	.read_time = pcf8583_rtc_read_time,
	279	.set_time = pcf8583_rtc_set_time,
	280	};
	281
	282	static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind);
	283
	284	static int pcf8583_attach(struct i2c_adapter *adap)
	285	{
	286	return i2c_probe(adap, &addr_data, pcf8583_probe);
	287	}
	288
	289	static int pcf8583_detach(struct i2c_client *client)
	290	{
	291	int err;
	292	struct pcf8583 *pcf = i2c_get_clientdata(client);
	293	struct rtc_device *rtc = pcf->rtc;
	294
	295	if (rtc)
	296	rtc_device_unregister(rtc);
	297
	298	if ((err = i2c_detach_client(client)))
	299	return err;
	300
	301	kfree(pcf);
	302	return 0;
	303	}
	304
	305	static struct i2c_driver pcf8583_driver = {
	306	.driver = {
	307	.name = "pcf8583",
	308	},
	309	.id = I2C_DRIVERID_PCF8583,
	310	.attach_adapter = pcf8583_attach,
	311	.detach_client = pcf8583_detach,
	312	};
	313
	314	static int pcf8583_probe(struct i2c_adapter *adap, int addr, int kind)
	315	{
	316	struct pcf8583 *pcf;
	317	struct i2c_client *client;
	318	struct rtc_device *rtc;
	319	unsigned char buf[1], ad[1] = { 0 };
	320	int err;
	321	struct i2c_msg msgs[2] = {
	322	{
	323	.addr = addr,
	324	.flags = 0,
	325	.len = 1,
	326	.buf = ad,
	327	}, {
	328	.addr = addr,
	329	.flags = I2C_M_RD,
	330	.len = 1,
	331	.buf = buf,
	332	}
	333	};
	334
c018664c JD	335	if (!i2c_check_functionality(adap, I2C_FUNC_I2C))
	336	return 0;
	337
9c0c5705 L	338	pcf = kzalloc(sizeof(*pcf), GFP_KERNEL);
	339	if (!pcf)
	340	return -ENOMEM;
	341
	342	client = &pcf->client;
	343
	344	client->addr = addr;
	345	client->adapter = adap;
	346	client->driver = &pcf8583_driver;
	347
	348	strlcpy(client->name, pcf8583_driver.driver.name, I2C_NAME_SIZE);
	349
	350	if (i2c_transfer(client->adapter, msgs, 2) != 2) {
	351	err = -EIO;
	352	goto exit_kfree;
	353	}
	354
	355	err = i2c_attach_client(client);
	356
	357	if (err)
	358	goto exit_kfree;
	359
	360	rtc = rtc_device_register(pcf8583_driver.driver.name, &client->dev,
	361	&pcf8583_rtc_ops, THIS_MODULE);
	362
	363	if (IS_ERR(rtc)) {
	364	err = PTR_ERR(rtc);
	365	goto exit_detach;
	366	}
	367
	368	pcf->rtc = rtc;
	369	i2c_set_clientdata(client, pcf);
	370	set_ctrl(client, buf[0]);
	371
	372	return 0;
	373
	374	exit_detach:
	375	i2c_detach_client(client);
	376
	377	exit_kfree:
	378	kfree(pcf);
	379
	380	return err;
	381	}
	382
	383	static __init int pcf8583_init(void)
	384	{
	385	return i2c_add_driver(&pcf8583_driver);
	386	}
	387
	388	static __exit void pcf8583_exit(void)
	389	{
	390	i2c_del_driver(&pcf8583_driver);
	391	}
	392
	393	module_init(pcf8583_init);
	394	module_exit(pcf8583_exit);
	395
	396	MODULE_AUTHOR("Russell King");
	397	MODULE_DESCRIPTION("PCF8583 I2C RTC driver");
	398	MODULE_LICENSE("GPL");