| /* |
| * drivers/i2c/chips/m41t00.c |
| * |
| * I2C client/driver for the ST M41T00 Real-Time Clock chip. |
| * |
| * Author: Mark A. Greer <mgreer@mvista.com> |
| * |
| * 2005 (c) MontaVista Software, Inc. This file is licensed under |
| * the terms of the GNU General Public License version 2. This program |
| * is licensed "as is" without any warranty of any kind, whether express |
| * or implied. |
| */ |
| /* |
| * This i2c client/driver wedges between the drivers/char/genrtc.c RTC |
| * interface and the SMBus interface of the i2c subsystem. |
| * It would be more efficient to use i2c msgs/i2c_transfer directly but, as |
| * recommened in .../Documentation/i2c/writing-clients section |
| * "Sending and receiving", using SMBus level communication is preferred. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/interrupt.h> |
| #include <linux/i2c.h> |
| #include <linux/rtc.h> |
| #include <linux/bcd.h> |
| |
| #include <asm/time.h> |
| #include <asm/rtc.h> |
| |
| #define M41T00_DRV_NAME "m41t00" |
| |
| static DECLARE_MUTEX(m41t00_mutex); |
| |
| static struct i2c_driver m41t00_driver; |
| static struct i2c_client *save_client; |
| |
| static unsigned short ignore[] = { I2C_CLIENT_END }; |
| static unsigned short normal_addr[] = { 0x68, I2C_CLIENT_END }; |
| |
| static struct i2c_client_address_data addr_data = { |
| .normal_i2c = normal_addr, |
| .probe = ignore, |
| .ignore = ignore, |
| }; |
| |
| ulong |
| m41t00_get_rtc_time(void) |
| { |
| s32 sec, min, hour, day, mon, year; |
| s32 sec1, min1, hour1, day1, mon1, year1; |
| ulong limit = 10; |
| |
| sec = min = hour = day = mon = year = 0; |
| sec1 = min1 = hour1 = day1 = mon1 = year1 = 0; |
| |
| down(&m41t00_mutex); |
| do { |
| if (((sec = i2c_smbus_read_byte_data(save_client, 0)) >= 0) |
| && ((min = i2c_smbus_read_byte_data(save_client, 1)) |
| >= 0) |
| && ((hour = i2c_smbus_read_byte_data(save_client, 2)) |
| >= 0) |
| && ((day = i2c_smbus_read_byte_data(save_client, 4)) |
| >= 0) |
| && ((mon = i2c_smbus_read_byte_data(save_client, 5)) |
| >= 0) |
| && ((year = i2c_smbus_read_byte_data(save_client, 6)) |
| >= 0) |
| && ((sec == sec1) && (min == min1) && (hour == hour1) |
| && (day == day1) && (mon == mon1) |
| && (year == year1))) |
| |
| break; |
| |
| sec1 = sec; |
| min1 = min; |
| hour1 = hour; |
| day1 = day; |
| mon1 = mon; |
| year1 = year; |
| } while (--limit > 0); |
| up(&m41t00_mutex); |
| |
| if (limit == 0) { |
| dev_warn(&save_client->dev, |
| "m41t00: can't read rtc chip\n"); |
| sec = min = hour = day = mon = year = 0; |
| } |
| |
| sec &= 0x7f; |
| min &= 0x7f; |
| hour &= 0x3f; |
| day &= 0x3f; |
| mon &= 0x1f; |
| year &= 0xff; |
| |
| BCD_TO_BIN(sec); |
| BCD_TO_BIN(min); |
| BCD_TO_BIN(hour); |
| BCD_TO_BIN(day); |
| BCD_TO_BIN(mon); |
| BCD_TO_BIN(year); |
| |
| year += 1900; |
| if (year < 1970) |
| year += 100; |
| |
| return mktime(year, mon, day, hour, min, sec); |
| } |
| |
| static void |
| m41t00_set_tlet(ulong arg) |
| { |
| struct rtc_time tm; |
| ulong nowtime = *(ulong *)arg; |
| |
| to_tm(nowtime, &tm); |
| tm.tm_year = (tm.tm_year - 1900) % 100; |
| |
| BIN_TO_BCD(tm.tm_sec); |
| BIN_TO_BCD(tm.tm_min); |
| BIN_TO_BCD(tm.tm_hour); |
| BIN_TO_BCD(tm.tm_mon); |
| BIN_TO_BCD(tm.tm_mday); |
| BIN_TO_BCD(tm.tm_year); |
| |
| down(&m41t00_mutex); |
| if ((i2c_smbus_write_byte_data(save_client, 0, tm.tm_sec & 0x7f) < 0) |
| || (i2c_smbus_write_byte_data(save_client, 1, tm.tm_min & 0x7f) |
| < 0) |
| || (i2c_smbus_write_byte_data(save_client, 2, tm.tm_hour & 0x7f) |
| < 0) |
| || (i2c_smbus_write_byte_data(save_client, 4, tm.tm_mday & 0x7f) |
| < 0) |
| || (i2c_smbus_write_byte_data(save_client, 5, tm.tm_mon & 0x7f) |
| < 0) |
| || (i2c_smbus_write_byte_data(save_client, 6, tm.tm_year & 0x7f) |
| < 0)) |
| |
| dev_warn(&save_client->dev,"m41t00: can't write to rtc chip\n"); |
| |
| up(&m41t00_mutex); |
| return; |
| } |
| |
| static ulong new_time; |
| |
| DECLARE_TASKLET_DISABLED(m41t00_tasklet, m41t00_set_tlet, (ulong)&new_time); |
| |
| int |
| m41t00_set_rtc_time(ulong nowtime) |
| { |
| new_time = nowtime; |
| |
| if (in_interrupt()) |
| tasklet_schedule(&m41t00_tasklet); |
| else |
| m41t00_set_tlet((ulong)&new_time); |
| |
| return 0; |
| } |
| |
| /* |
| ***************************************************************************** |
| * |
| * Driver Interface |
| * |
| ***************************************************************************** |
| */ |
| static int |
| m41t00_probe(struct i2c_adapter *adap, int addr, int kind) |
| { |
| struct i2c_client *client; |
| int rc; |
| |
| client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL); |
| if (!client) |
| return -ENOMEM; |
| |
| memset(client, 0, sizeof(struct i2c_client)); |
| strncpy(client->name, M41T00_DRV_NAME, I2C_NAME_SIZE); |
| client->flags = I2C_DF_NOTIFY; |
| client->addr = addr; |
| client->adapter = adap; |
| client->driver = &m41t00_driver; |
| |
| if ((rc = i2c_attach_client(client)) != 0) { |
| kfree(client); |
| return rc; |
| } |
| |
| save_client = client; |
| return 0; |
| } |
| |
| static int |
| m41t00_attach(struct i2c_adapter *adap) |
| { |
| return i2c_probe(adap, &addr_data, m41t00_probe); |
| } |
| |
| static int |
| m41t00_detach(struct i2c_client *client) |
| { |
| int rc; |
| |
| if ((rc = i2c_detach_client(client)) == 0) { |
| kfree(client); |
| tasklet_kill(&m41t00_tasklet); |
| } |
| return rc; |
| } |
| |
| static struct i2c_driver m41t00_driver = { |
| .owner = THIS_MODULE, |
| .name = M41T00_DRV_NAME, |
| .id = I2C_DRIVERID_STM41T00, |
| .flags = I2C_DF_NOTIFY, |
| .attach_adapter = m41t00_attach, |
| .detach_client = m41t00_detach, |
| }; |
| |
| static int __init |
| m41t00_init(void) |
| { |
| return i2c_add_driver(&m41t00_driver); |
| } |
| |
| static void __exit |
| m41t00_exit(void) |
| { |
| i2c_del_driver(&m41t00_driver); |
| return; |
| } |
| |
| module_init(m41t00_init); |
| module_exit(m41t00_exit); |
| |
| MODULE_AUTHOR("Mark A. Greer <mgreer@mvista.com>"); |
| MODULE_DESCRIPTION("ST Microelectronics M41T00 RTC I2C Client Driver"); |
| MODULE_LICENSE("GPL"); |