2 * linux/drivers/i2c/chips/ds1337.c
4 * Copyright (C) 2005 James Chapman <jchapman@katalix.com>
6 * based on linux/drivers/acorn/char/pcf8583.c
7 * Copyright (C) 2000 Russell King
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
13 * Driver for Dallas Semiconductor DS1337 and DS1339 real time clock chip
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/slab.h>
19 #include <linux/i2c.h>
20 #include <linux/string.h>
21 #include <linux/rtc.h> /* get the user-level API */
22 #include <linux/bcd.h>
23 #include <linux/list.h>
25 /* Device registers */
26 #define DS1337_REG_HOUR 2
27 #define DS1337_REG_DAY 3
28 #define DS1337_REG_DATE 4
29 #define DS1337_REG_MONTH 5
30 #define DS1337_REG_CONTROL 14
31 #define DS1337_REG_STATUS 15
33 /* FIXME - how do we export these interface constants? */
34 #define DS1337_GET_DATE 0
35 #define DS1337_SET_DATE 1
38 * Functions declaration
40 static unsigned short normal_i2c
[] = { 0x68, I2C_CLIENT_END
};
42 I2C_CLIENT_INSMOD_1(ds1337
);
44 static int ds1337_attach_adapter(struct i2c_adapter
*adapter
);
45 static int ds1337_detect(struct i2c_adapter
*adapter
, int address
, int kind
);
46 static void ds1337_init_client(struct i2c_client
*client
);
47 static int ds1337_detach_client(struct i2c_client
*client
);
48 static int ds1337_command(struct i2c_client
*client
, unsigned int cmd
,
52 * Driver data (common to all clients)
54 static struct i2c_driver ds1337_driver
= {
58 .attach_adapter
= ds1337_attach_adapter
,
59 .detach_client
= ds1337_detach_client
,
60 .command
= ds1337_command
,
64 * Client data (each client gets its own)
67 struct i2c_client client
;
68 struct list_head list
;
74 static LIST_HEAD(ds1337_clients
);
76 static inline int ds1337_read(struct i2c_client
*client
, u8 reg
, u8
*value
)
78 s32 tmp
= i2c_smbus_read_byte_data(client
, reg
);
89 * Chip access functions
91 static int ds1337_get_datetime(struct i2c_client
*client
, struct rtc_time
*dt
)
96 struct i2c_msg msg
[2];
100 dev_dbg(&client
->dev
, "%s: EINVAL: dt=NULL\n", __FUNCTION__
);
104 msg
[0].addr
= client
->addr
;
109 msg
[1].addr
= client
->addr
;
110 msg
[1].flags
= I2C_M_RD
;
111 msg
[1].len
= sizeof(buf
);
112 msg
[1].buf
= &buf
[0];
114 result
= i2c_transfer(client
->adapter
, msg
, 2);
116 dev_dbg(&client
->dev
, "%s: [%d] %02x %02x %02x %02x %02x %02x %02x\n",
117 __FUNCTION__
, result
, buf
[0], buf
[1], buf
[2], buf
[3],
118 buf
[4], buf
[5], buf
[6]);
121 dt
->tm_sec
= BCD2BIN(buf
[0]);
122 dt
->tm_min
= BCD2BIN(buf
[1]);
124 dt
->tm_hour
= BCD2BIN(val
);
125 dt
->tm_wday
= BCD2BIN(buf
[3]) - 1;
126 dt
->tm_mday
= BCD2BIN(buf
[4]);
128 dt
->tm_mon
= BCD2BIN(val
) - 1;
129 dt
->tm_year
= BCD2BIN(buf
[6]);
133 dev_dbg(&client
->dev
, "%s: secs=%d, mins=%d, "
134 "hours=%d, mday=%d, mon=%d, year=%d, wday=%d\n",
135 __FUNCTION__
, dt
->tm_sec
, dt
->tm_min
,
136 dt
->tm_hour
, dt
->tm_mday
,
137 dt
->tm_mon
, dt
->tm_year
, dt
->tm_wday
);
142 dev_err(&client
->dev
, "error reading data! %d\n", result
);
146 static int ds1337_set_datetime(struct i2c_client
*client
, struct rtc_time
*dt
)
151 struct i2c_msg msg
[1];
154 dev_dbg(&client
->dev
, "%s: EINVAL: dt=NULL\n", __FUNCTION__
);
158 dev_dbg(&client
->dev
, "%s: secs=%d, mins=%d, hours=%d, "
159 "mday=%d, mon=%d, year=%d, wday=%d\n", __FUNCTION__
,
160 dt
->tm_sec
, dt
->tm_min
, dt
->tm_hour
,
161 dt
->tm_mday
, dt
->tm_mon
, dt
->tm_year
, dt
->tm_wday
);
163 buf
[0] = 0; /* reg offset */
164 buf
[1] = BIN2BCD(dt
->tm_sec
);
165 buf
[2] = BIN2BCD(dt
->tm_min
);
166 buf
[3] = BIN2BCD(dt
->tm_hour
);
167 buf
[4] = BIN2BCD(dt
->tm_wday
+ 1);
168 buf
[5] = BIN2BCD(dt
->tm_mday
);
169 buf
[6] = BIN2BCD(dt
->tm_mon
+ 1);
175 buf
[7] = BIN2BCD(val
);
177 msg
[0].addr
= client
->addr
;
179 msg
[0].len
= sizeof(buf
);
180 msg
[0].buf
= &buf
[0];
182 result
= i2c_transfer(client
->adapter
, msg
, 1);
186 dev_err(&client
->dev
, "error writing data! %d\n", result
);
190 static int ds1337_command(struct i2c_client
*client
, unsigned int cmd
,
193 dev_dbg(&client
->dev
, "%s: cmd=%d\n", __FUNCTION__
, cmd
);
196 case DS1337_GET_DATE
:
197 return ds1337_get_datetime(client
, arg
);
199 case DS1337_SET_DATE
:
200 return ds1337_set_datetime(client
, arg
);
208 * Public API for access to specific device. Useful for low-level
209 * RTC access from kernel code.
211 int ds1337_do_command(int bus
, int cmd
, void *arg
)
213 struct list_head
*walk
;
214 struct list_head
*tmp
;
215 struct ds1337_data
*data
;
217 list_for_each_safe(walk
, tmp
, &ds1337_clients
) {
218 data
= list_entry(walk
, struct ds1337_data
, list
);
219 if (data
->client
.adapter
->nr
== bus
)
220 return ds1337_command(&data
->client
, cmd
, arg
);
226 static int ds1337_attach_adapter(struct i2c_adapter
*adapter
)
228 return i2c_probe(adapter
, &addr_data
, ds1337_detect
);
232 * The following function does more than just detection. If detection
233 * succeeds, it also registers the new chip.
235 static int ds1337_detect(struct i2c_adapter
*adapter
, int address
, int kind
)
237 struct i2c_client
*new_client
;
238 struct ds1337_data
*data
;
240 const char *name
= "";
242 if (!i2c_check_functionality(adapter
, I2C_FUNC_SMBUS_BYTE_DATA
|
246 if (!(data
= kzalloc(sizeof(struct ds1337_data
), GFP_KERNEL
))) {
250 INIT_LIST_HEAD(&data
->list
);
252 /* The common I2C client data is placed right before the
253 * DS1337-specific data.
255 new_client
= &data
->client
;
256 i2c_set_clientdata(new_client
, data
);
257 new_client
->addr
= address
;
258 new_client
->adapter
= adapter
;
259 new_client
->driver
= &ds1337_driver
;
260 new_client
->flags
= 0;
263 * Now we do the remaining detection. A negative kind means that
264 * the driver was loaded with no force parameter (default), so we
265 * must both detect and identify the chip. A zero kind means that
266 * the driver was loaded with the force parameter, the detection
267 * step shall be skipped. A positive kind means that the driver
268 * was loaded with the force parameter and a given kind of chip is
269 * requested, so both the detection and the identification steps
272 * For detection, we read registers that are most likely to cause
273 * detection failure, i.e. those that have more bits with fixed
274 * or reserved values.
277 /* Default to an DS1337 if forced */
281 if (kind
< 0) { /* detection and identification */
284 /* Check that status register bits 6-2 are zero */
285 if ((ds1337_read(new_client
, DS1337_REG_STATUS
, &data
) < 0) ||
289 /* Check for a valid day register value */
290 if ((ds1337_read(new_client
, DS1337_REG_DAY
, &data
) < 0) ||
291 (data
== 0) || (data
& 0xf8))
294 /* Check for a valid date register value */
295 if ((ds1337_read(new_client
, DS1337_REG_DATE
, &data
) < 0) ||
296 (data
== 0) || (data
& 0xc0) || ((data
& 0x0f) > 9) ||
300 /* Check for a valid month register value */
301 if ((ds1337_read(new_client
, DS1337_REG_MONTH
, &data
) < 0) ||
302 (data
== 0) || (data
& 0x60) || ((data
& 0x0f) > 9) ||
303 ((data
>= 0x13) && (data
<= 0x19)))
306 /* Check that control register bits 6-5 are zero */
307 if ((ds1337_read(new_client
, DS1337_REG_CONTROL
, &data
) < 0) ||
317 /* We can fill in the remaining client fields */
318 strlcpy(new_client
->name
, name
, I2C_NAME_SIZE
);
320 /* Tell the I2C layer a new client has arrived */
321 if ((err
= i2c_attach_client(new_client
)))
324 /* Initialize the DS1337 chip */
325 ds1337_init_client(new_client
);
327 /* Add client to local list */
328 list_add(&data
->list
, &ds1337_clients
);
338 static void ds1337_init_client(struct i2c_client
*client
)
342 /* On some boards, the RTC isn't configured by boot firmware.
343 * Handle that case by starting/configuring the RTC now.
345 status
= i2c_smbus_read_byte_data(client
, DS1337_REG_STATUS
);
346 control
= i2c_smbus_read_byte_data(client
, DS1337_REG_CONTROL
);
348 if ((status
& 0x80) || (control
& 0x80)) {
349 /* RTC not running */
351 struct i2c_msg msg
[1];
353 dev_dbg(&client
->dev
, "%s: RTC not running!\n", __FUNCTION__
);
355 /* Initialize all, including STATUS and CONTROL to zero */
356 memset(buf
, 0, sizeof(buf
));
357 msg
[0].addr
= client
->addr
;
359 msg
[0].len
= sizeof(buf
);
360 msg
[0].buf
= &buf
[0];
362 i2c_transfer(client
->adapter
, msg
, 1);
364 /* Running: ensure that device is set in 24-hour mode */
367 val
= i2c_smbus_read_byte_data(client
, DS1337_REG_HOUR
);
368 if ((val
>= 0) && (val
& (1 << 6)))
369 i2c_smbus_write_byte_data(client
, DS1337_REG_HOUR
,
374 static int ds1337_detach_client(struct i2c_client
*client
)
377 struct ds1337_data
*data
= i2c_get_clientdata(client
);
379 if ((err
= i2c_detach_client(client
)))
382 list_del(&data
->list
);
387 static int __init
ds1337_init(void)
389 return i2c_add_driver(&ds1337_driver
);
392 static void __exit
ds1337_exit(void)
394 i2c_del_driver(&ds1337_driver
);
397 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
398 MODULE_DESCRIPTION("DS1337 RTC driver");
399 MODULE_LICENSE("GPL");
401 EXPORT_SYMBOL_GPL(ds1337_do_command
);
403 module_init(ds1337_init
);
404 module_exit(ds1337_exit
);