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v4.6
  1/*
  2 * An I2C driver for the Epson RX8581 RTC
  3 *
  4 * Author: Martyn Welch <martyn.welch@ge.com>
  5 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 *
 11 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)
 12 * Copyright 2005-06 Tower Technologies
 13 */
 14
 15#include <linux/module.h>
 16#include <linux/i2c.h>
 17#include <linux/bcd.h>
 18#include <linux/rtc.h>
 19#include <linux/log2.h>
 20
 21#define DRV_VERSION "0.1"
 22
 23#define RX8581_REG_SC		0x00 /* Second in BCD */
 24#define RX8581_REG_MN		0x01 /* Minute in BCD */
 25#define RX8581_REG_HR		0x02 /* Hour in BCD */
 26#define RX8581_REG_DW		0x03 /* Day of Week */
 27#define RX8581_REG_DM		0x04 /* Day of Month in BCD */
 28#define RX8581_REG_MO		0x05 /* Month in BCD */
 29#define RX8581_REG_YR		0x06 /* Year in BCD */
 30#define RX8581_REG_RAM		0x07 /* RAM */
 31#define RX8581_REG_AMN		0x08 /* Alarm Min in BCD*/
 32#define RX8581_REG_AHR		0x09 /* Alarm Hour in BCD */
 33#define RX8581_REG_ADM		0x0A
 34#define RX8581_REG_ADW		0x0A
 35#define RX8581_REG_TMR0		0x0B
 36#define RX8581_REG_TMR1		0x0C
 37#define RX8581_REG_EXT		0x0D /* Extension Register */
 38#define RX8581_REG_FLAG		0x0E /* Flag Register */
 39#define RX8581_REG_CTRL		0x0F /* Control Register */
 40
 41
 42/* Flag Register bit definitions */
 43#define RX8581_FLAG_UF		0x20 /* Update */
 44#define RX8581_FLAG_TF		0x10 /* Timer */
 45#define RX8581_FLAG_AF		0x08 /* Alarm */
 46#define RX8581_FLAG_VLF		0x02 /* Voltage Low */
 47
 48/* Control Register bit definitions */
 49#define RX8581_CTRL_UIE		0x20 /* Update Interrupt Enable */
 50#define RX8581_CTRL_TIE		0x10 /* Timer Interrupt Enable */
 51#define RX8581_CTRL_AIE		0x08 /* Alarm Interrupt Enable */
 52#define RX8581_CTRL_STOP	0x02 /* STOP bit */
 53#define RX8581_CTRL_RESET	0x01 /* RESET bit */
 54
 55struct rx8581 {
 56	struct i2c_client	*client;
 57	struct rtc_device	*rtc;
 58	s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 59				u8 length, u8 *values);
 60	s32 (*write_block_data)(const struct i2c_client *client, u8 command,
 61				u8 length, const u8 *values);
 62};
 63
 64static struct i2c_driver rx8581_driver;
 65
 66static int rx8581_read_block_data(const struct i2c_client *client, u8 command,
 67					u8 length, u8 *values)
 68{
 69	s32 i, data;
 70
 71	for (i = 0; i < length; i++) {
 72		data = i2c_smbus_read_byte_data(client, command + i);
 73		if (data < 0)
 74			return data;
 75		values[i] = data;
 76	}
 77	return i;
 78}
 79
 80static int rx8581_write_block_data(const struct i2c_client *client, u8 command,
 81					u8 length, const u8 *values)
 82{
 83	s32 i, ret;
 84
 85	for (i = 0; i < length; i++) {
 86		ret = i2c_smbus_write_byte_data(client, command + i,
 87						values[i]);
 88		if (ret < 0)
 89			return ret;
 90	}
 91	return length;
 92}
 93
 94/*
 95 * In the routines that deal directly with the rx8581 hardware, we use
 96 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
 97 */
 98static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm)
 99{
100	unsigned char date[7];
101	int data, err;
102	struct rx8581 *rx8581 = i2c_get_clientdata(client);
103
104	/* First we ensure that the "update flag" is not set, we read the
105	 * time and date then re-read the "update flag". If the update flag
106	 * has been set, we know that the time has changed during the read so
107	 * we repeat the whole process again.
108	 */
109	data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
110	if (data < 0) {
111		dev_err(&client->dev, "Unable to read device flags\n");
112		return -EIO;
113	}
114
115	do {
116		/* If update flag set, clear it */
117		if (data & RX8581_FLAG_UF) {
118			err = i2c_smbus_write_byte_data(client,
119				RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF));
120			if (err != 0) {
121				dev_err(&client->dev, "Unable to write device flags\n");
122				return -EIO;
123			}
124		}
125
126		/* Now read time and date */
127		err = rx8581->read_block_data(client, RX8581_REG_SC,
128			7, date);
129		if (err < 0) {
130			dev_err(&client->dev, "Unable to read date\n");
131			return -EIO;
132		}
133
134		/* Check flag register */
135		data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
136		if (data < 0) {
137			dev_err(&client->dev, "Unable to read device flags\n");
138			return -EIO;
139		}
140	} while (data & RX8581_FLAG_UF);
141
142	if (data & RX8581_FLAG_VLF)
143		dev_info(&client->dev,
144			"low voltage detected, date/time is not reliable.\n");
145
146	dev_dbg(&client->dev,
147		"%s: raw data is sec=%02x, min=%02x, hr=%02x, "
148		"wday=%02x, mday=%02x, mon=%02x, year=%02x\n",
149		__func__,
150		date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
151
152	tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
153	tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
154	tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
155	tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
156	tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
157	tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
158	tm->tm_year = bcd2bin(date[RX8581_REG_YR]);
159	if (tm->tm_year < 70)
160		tm->tm_year += 100;	/* assume we are in 1970...2069 */
161
162
163	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
164		"mday=%d, mon=%d, year=%d, wday=%d\n",
165		__func__,
166		tm->tm_sec, tm->tm_min, tm->tm_hour,
167		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
168
169	err = rtc_valid_tm(tm);
170	if (err < 0)
171		dev_err(&client->dev, "retrieved date/time is not valid.\n");
172
173	return err;
174}
175
176static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm)
177{
178	int data, err;
179	unsigned char buf[7];
180	struct rx8581 *rx8581 = i2c_get_clientdata(client);
181
182	dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
183		"mday=%d, mon=%d, year=%d, wday=%d\n",
184		__func__,
185		tm->tm_sec, tm->tm_min, tm->tm_hour,
186		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
187
188	/* hours, minutes and seconds */
189	buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
190	buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
191	buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);
192
193	buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);
194
195	/* month, 1 - 12 */
196	buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);
197
198	/* year and century */
199	buf[RX8581_REG_YR] = bin2bcd(tm->tm_year % 100);
200	buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);
201
202	/* Stop the clock */
203	data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
204	if (data < 0) {
205		dev_err(&client->dev, "Unable to read control register\n");
206		return -EIO;
207	}
208
209	err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL,
210		(data | RX8581_CTRL_STOP));
211	if (err < 0) {
212		dev_err(&client->dev, "Unable to write control register\n");
213		return -EIO;
214	}
215
216	/* write register's data */
217	err = rx8581->write_block_data(client, RX8581_REG_SC, 7, buf);
218	if (err < 0) {
219		dev_err(&client->dev, "Unable to write to date registers\n");
220		return -EIO;
221	}
222
223	/* get VLF and clear it */
224	data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
225	if (data < 0) {
226		dev_err(&client->dev, "Unable to read flag register\n");
227		return -EIO;
228	}
229
230	err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG,
231		(data & ~(RX8581_FLAG_VLF)));
232	if (err != 0) {
233		dev_err(&client->dev, "Unable to write flag register\n");
234		return -EIO;
235	}
236
237	/* Restart the clock */
238	data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
239	if (data < 0) {
240		dev_err(&client->dev, "Unable to read control register\n");
241		return -EIO;
242	}
243
244	err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL,
245		(data & ~(RX8581_CTRL_STOP)));
246	if (err != 0) {
247		dev_err(&client->dev, "Unable to write control register\n");
248		return -EIO;
249	}
250
251	return 0;
252}
253
254static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
255{
256	return rx8581_get_datetime(to_i2c_client(dev), tm);
257}
258
259static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
260{
261	return rx8581_set_datetime(to_i2c_client(dev), tm);
262}
263
264static const struct rtc_class_ops rx8581_rtc_ops = {
265	.read_time	= rx8581_rtc_read_time,
266	.set_time	= rx8581_rtc_set_time,
267};
268
269static int rx8581_probe(struct i2c_client *client,
270			const struct i2c_device_id *id)
271{
272	struct rx8581	  *rx8581;
273
274	dev_dbg(&client->dev, "%s\n", __func__);
275
276	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)
277		&& !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
278		return -EIO;
279
280	rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
281	if (!rx8581)
282		return -ENOMEM;
283
284	i2c_set_clientdata(client, rx8581);
285	rx8581->client = client;
286
287	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
288		rx8581->read_block_data = i2c_smbus_read_i2c_block_data;
289		rx8581->write_block_data = i2c_smbus_write_i2c_block_data;
290	} else {
291		rx8581->read_block_data = rx8581_read_block_data;
292		rx8581->write_block_data = rx8581_write_block_data;
293	}
294
295	dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n");
296
297	rx8581->rtc = devm_rtc_device_register(&client->dev,
298		rx8581_driver.driver.name, &rx8581_rtc_ops, THIS_MODULE);
299
300	if (IS_ERR(rx8581->rtc)) {
301		dev_err(&client->dev,
302			"unable to register the class device\n");
303		return PTR_ERR(rx8581->rtc);
304	}
305
306	return 0;
307}
308
309static const struct i2c_device_id rx8581_id[] = {
310	{ "rx8581", 0 },
311	{ }
312};
313MODULE_DEVICE_TABLE(i2c, rx8581_id);
314
 
 
 
 
 
 
315static struct i2c_driver rx8581_driver = {
316	.driver		= {
317		.name	= "rtc-rx8581",
 
318	},
319	.probe		= rx8581_probe,
320	.id_table	= rx8581_id,
321};
322
323module_i2c_driver(rx8581_driver);
324
325MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
326MODULE_DESCRIPTION("Epson RX-8581 RTC driver");
327MODULE_LICENSE("GPL");
328MODULE_VERSION(DRV_VERSION);
v4.17
  1/*
  2 * An I2C driver for the Epson RX8581 RTC
  3 *
  4 * Author: Martyn Welch <martyn.welch@ge.com>
  5 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 *
 11 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)
 12 * Copyright 2005-06 Tower Technologies
 13 */
 14
 15#include <linux/module.h>
 16#include <linux/i2c.h>
 17#include <linux/bcd.h>
 18#include <linux/rtc.h>
 19#include <linux/log2.h>
 20
 
 
 21#define RX8581_REG_SC		0x00 /* Second in BCD */
 22#define RX8581_REG_MN		0x01 /* Minute in BCD */
 23#define RX8581_REG_HR		0x02 /* Hour in BCD */
 24#define RX8581_REG_DW		0x03 /* Day of Week */
 25#define RX8581_REG_DM		0x04 /* Day of Month in BCD */
 26#define RX8581_REG_MO		0x05 /* Month in BCD */
 27#define RX8581_REG_YR		0x06 /* Year in BCD */
 28#define RX8581_REG_RAM		0x07 /* RAM */
 29#define RX8581_REG_AMN		0x08 /* Alarm Min in BCD*/
 30#define RX8581_REG_AHR		0x09 /* Alarm Hour in BCD */
 31#define RX8581_REG_ADM		0x0A
 32#define RX8581_REG_ADW		0x0A
 33#define RX8581_REG_TMR0		0x0B
 34#define RX8581_REG_TMR1		0x0C
 35#define RX8581_REG_EXT		0x0D /* Extension Register */
 36#define RX8581_REG_FLAG		0x0E /* Flag Register */
 37#define RX8581_REG_CTRL		0x0F /* Control Register */
 38
 39
 40/* Flag Register bit definitions */
 41#define RX8581_FLAG_UF		0x20 /* Update */
 42#define RX8581_FLAG_TF		0x10 /* Timer */
 43#define RX8581_FLAG_AF		0x08 /* Alarm */
 44#define RX8581_FLAG_VLF		0x02 /* Voltage Low */
 45
 46/* Control Register bit definitions */
 47#define RX8581_CTRL_UIE		0x20 /* Update Interrupt Enable */
 48#define RX8581_CTRL_TIE		0x10 /* Timer Interrupt Enable */
 49#define RX8581_CTRL_AIE		0x08 /* Alarm Interrupt Enable */
 50#define RX8581_CTRL_STOP	0x02 /* STOP bit */
 51#define RX8581_CTRL_RESET	0x01 /* RESET bit */
 52
 53struct rx8581 {
 54	struct i2c_client	*client;
 55	struct rtc_device	*rtc;
 56	s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 57				u8 length, u8 *values);
 58	s32 (*write_block_data)(const struct i2c_client *client, u8 command,
 59				u8 length, const u8 *values);
 60};
 61
 62static struct i2c_driver rx8581_driver;
 63
 64static int rx8581_read_block_data(const struct i2c_client *client, u8 command,
 65					u8 length, u8 *values)
 66{
 67	s32 i, data;
 68
 69	for (i = 0; i < length; i++) {
 70		data = i2c_smbus_read_byte_data(client, command + i);
 71		if (data < 0)
 72			return data;
 73		values[i] = data;
 74	}
 75	return i;
 76}
 77
 78static int rx8581_write_block_data(const struct i2c_client *client, u8 command,
 79					u8 length, const u8 *values)
 80{
 81	s32 i, ret;
 82
 83	for (i = 0; i < length; i++) {
 84		ret = i2c_smbus_write_byte_data(client, command + i,
 85						values[i]);
 86		if (ret < 0)
 87			return ret;
 88	}
 89	return length;
 90}
 91
 92/*
 93 * In the routines that deal directly with the rx8581 hardware, we use
 94 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.
 95 */
 96static int rx8581_get_datetime(struct i2c_client *client, struct rtc_time *tm)
 97{
 98	unsigned char date[7];
 99	int data, err;
100	struct rx8581 *rx8581 = i2c_get_clientdata(client);
101
102	/* First we ensure that the "update flag" is not set, we read the
103	 * time and date then re-read the "update flag". If the update flag
104	 * has been set, we know that the time has changed during the read so
105	 * we repeat the whole process again.
106	 */
107	data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
108	if (data < 0) {
109		dev_err(&client->dev, "Unable to read device flags\n");
110		return -EIO;
111	}
112
113	do {
114		/* If update flag set, clear it */
115		if (data & RX8581_FLAG_UF) {
116			err = i2c_smbus_write_byte_data(client,
117				RX8581_REG_FLAG, (data & ~RX8581_FLAG_UF));
118			if (err != 0) {
119				dev_err(&client->dev, "Unable to write device flags\n");
120				return -EIO;
121			}
122		}
123
124		/* Now read time and date */
125		err = rx8581->read_block_data(client, RX8581_REG_SC,
126			7, date);
127		if (err < 0) {
128			dev_err(&client->dev, "Unable to read date\n");
129			return -EIO;
130		}
131
132		/* Check flag register */
133		data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
134		if (data < 0) {
135			dev_err(&client->dev, "Unable to read device flags\n");
136			return -EIO;
137		}
138	} while (data & RX8581_FLAG_UF);
139
140	if (data & RX8581_FLAG_VLF)
141		dev_info(&client->dev,
142			"low voltage detected, date/time is not reliable.\n");
143
144	dev_dbg(&client->dev,
145		"%s: raw data is sec=%02x, min=%02x, hr=%02x, "
146		"wday=%02x, mday=%02x, mon=%02x, year=%02x\n",
147		__func__,
148		date[0], date[1], date[2], date[3], date[4], date[5], date[6]);
149
150	tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);
151	tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);
152	tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */
153	tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);
154	tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);
155	tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */
156	tm->tm_year = bcd2bin(date[RX8581_REG_YR]);
157	if (tm->tm_year < 70)
158		tm->tm_year += 100;	/* assume we are in 1970...2069 */
159
160
161	dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, "
162		"mday=%d, mon=%d, year=%d, wday=%d\n",
163		__func__,
164		tm->tm_sec, tm->tm_min, tm->tm_hour,
165		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
166
167	return 0;
 
 
 
 
168}
169
170static int rx8581_set_datetime(struct i2c_client *client, struct rtc_time *tm)
171{
172	int data, err;
173	unsigned char buf[7];
174	struct rx8581 *rx8581 = i2c_get_clientdata(client);
175
176	dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, "
177		"mday=%d, mon=%d, year=%d, wday=%d\n",
178		__func__,
179		tm->tm_sec, tm->tm_min, tm->tm_hour,
180		tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);
181
182	/* hours, minutes and seconds */
183	buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);
184	buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);
185	buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);
186
187	buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);
188
189	/* month, 1 - 12 */
190	buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);
191
192	/* year and century */
193	buf[RX8581_REG_YR] = bin2bcd(tm->tm_year % 100);
194	buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);
195
196	/* Stop the clock */
197	data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
198	if (data < 0) {
199		dev_err(&client->dev, "Unable to read control register\n");
200		return -EIO;
201	}
202
203	err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL,
204		(data | RX8581_CTRL_STOP));
205	if (err < 0) {
206		dev_err(&client->dev, "Unable to write control register\n");
207		return -EIO;
208	}
209
210	/* write register's data */
211	err = rx8581->write_block_data(client, RX8581_REG_SC, 7, buf);
212	if (err < 0) {
213		dev_err(&client->dev, "Unable to write to date registers\n");
214		return -EIO;
215	}
216
217	/* get VLF and clear it */
218	data = i2c_smbus_read_byte_data(client, RX8581_REG_FLAG);
219	if (data < 0) {
220		dev_err(&client->dev, "Unable to read flag register\n");
221		return -EIO;
222	}
223
224	err = i2c_smbus_write_byte_data(client, RX8581_REG_FLAG,
225		(data & ~(RX8581_FLAG_VLF)));
226	if (err != 0) {
227		dev_err(&client->dev, "Unable to write flag register\n");
228		return -EIO;
229	}
230
231	/* Restart the clock */
232	data = i2c_smbus_read_byte_data(client, RX8581_REG_CTRL);
233	if (data < 0) {
234		dev_err(&client->dev, "Unable to read control register\n");
235		return -EIO;
236	}
237
238	err = i2c_smbus_write_byte_data(client, RX8581_REG_CTRL,
239		(data & ~(RX8581_CTRL_STOP)));
240	if (err != 0) {
241		dev_err(&client->dev, "Unable to write control register\n");
242		return -EIO;
243	}
244
245	return 0;
246}
247
248static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)
249{
250	return rx8581_get_datetime(to_i2c_client(dev), tm);
251}
252
253static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)
254{
255	return rx8581_set_datetime(to_i2c_client(dev), tm);
256}
257
258static const struct rtc_class_ops rx8581_rtc_ops = {
259	.read_time	= rx8581_rtc_read_time,
260	.set_time	= rx8581_rtc_set_time,
261};
262
263static int rx8581_probe(struct i2c_client *client,
264			const struct i2c_device_id *id)
265{
266	struct rx8581	  *rx8581;
267
268	dev_dbg(&client->dev, "%s\n", __func__);
269
270	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)
271		&& !i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
272		return -EIO;
273
274	rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);
275	if (!rx8581)
276		return -ENOMEM;
277
278	i2c_set_clientdata(client, rx8581);
279	rx8581->client = client;
280
281	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) {
282		rx8581->read_block_data = i2c_smbus_read_i2c_block_data;
283		rx8581->write_block_data = i2c_smbus_write_i2c_block_data;
284	} else {
285		rx8581->read_block_data = rx8581_read_block_data;
286		rx8581->write_block_data = rx8581_write_block_data;
287	}
288
 
 
289	rx8581->rtc = devm_rtc_device_register(&client->dev,
290		rx8581_driver.driver.name, &rx8581_rtc_ops, THIS_MODULE);
291
292	if (IS_ERR(rx8581->rtc)) {
293		dev_err(&client->dev,
294			"unable to register the class device\n");
295		return PTR_ERR(rx8581->rtc);
296	}
297
298	return 0;
299}
300
301static const struct i2c_device_id rx8581_id[] = {
302	{ "rx8581", 0 },
303	{ }
304};
305MODULE_DEVICE_TABLE(i2c, rx8581_id);
306
307static const struct of_device_id rx8581_of_match[] = {
308	{ .compatible = "epson,rx8581" },
309	{ }
310};
311MODULE_DEVICE_TABLE(of, rx8581_of_match);
312
313static struct i2c_driver rx8581_driver = {
314	.driver		= {
315		.name	= "rtc-rx8581",
316		.of_match_table = of_match_ptr(rx8581_of_match),
317	},
318	.probe		= rx8581_probe,
319	.id_table	= rx8581_id,
320};
321
322module_i2c_driver(rx8581_driver);
323
324MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
325MODULE_DESCRIPTION("Epson RX-8581 RTC driver");
326MODULE_LICENSE("GPL");