diff options
Diffstat (limited to 'drivers/i2c/chips/m41t00.c')
| -rw-r--r-- | drivers/i2c/chips/m41t00.c | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/drivers/i2c/chips/m41t00.c b/drivers/i2c/chips/m41t00.c new file mode 100644 index 00000000000..e771566dffa --- /dev/null +++ b/drivers/i2c/chips/m41t00.c @@ -0,0 +1,246 @@ +/* + * 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, + .normal_i2c_range = ignore, + .probe = ignore, + .probe_range = ignore, + .ignore = ignore, + .ignore_range = ignore, + .force = 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; +} + +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(i2c_get_clientdata(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"); |