/* * I2C client/driver for the ST M41T00 family of i2c rtc chips. * * Author: Mark A. Greer <mgreer@mvista.com> * * 2005, 2006 (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. */ #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 <linux/workqueue.h> #include <linux/platform_device.h> #include <linux/m41t00.h> #include <asm/time.h> #include <asm/rtc.h> static struct i2c_driver m41t00_driver; static struct i2c_client *save_client; static unsigned short ignore[] = { I2C_CLIENT_END }; static unsigned short normal_addr[] = { I2C_CLIENT_END, I2C_CLIENT_END }; static struct i2c_client_address_data addr_data = { .normal_i2c = normal_addr, .probe = ignore, .ignore = ignore, }; struct m41t00_chip_info { u8 type; char *name; u8 read_limit; u8 sec; /* Offsets for chip regs */ u8 min; u8 hour; u8 day; u8 mon; u8 year; u8 alarm_mon; u8 alarm_hour; u8 sqw; u8 sqw_freq; }; static struct m41t00_chip_info m41t00_chip_info_tbl[] = { { .type = M41T00_TYPE_M41T00, .name = "m41t00", .read_limit = 5, .sec = 0, .min = 1, .hour = 2, .day = 4, .mon = 5, .year = 6, }, { .type = M41T00_TYPE_M41T81, .name = "m41t81", .read_limit = 1, .sec = 1, .min = 2, .hour = 3, .day = 5, .mon = 6, .year = 7, .alarm_mon = 0xa, .alarm_hour = 0xc, .sqw = 0x13, }, { .type = M41T00_TYPE_M41T85, .name = "m41t85", .read_limit = 1, .sec = 1, .min = 2, .hour = 3, .day = 5, .mon = 6, .year = 7, .alarm_mon = 0xa, .alarm_hour = 0xc, .sqw = 0x13, }, }; static struct m41t00_chip_info *m41t00_chip; ulong m41t00_get_rtc_time(void) { s32 sec, min, hour, day, mon, year; s32 sec1, min1, hour1, day1, mon1, year1; u8 reads = 0; u8 buf[8], msgbuf[1] = { 0 }; /* offset into rtc's regs */ struct i2c_msg msgs[] = { { .addr = save_client->addr, .flags = 0, .len = 1, .buf = msgbuf, }, { .addr = save_client->addr, .flags = I2C_M_RD, .len = 8, .buf = buf, }, }; sec = min = hour = day = mon = year = 0; do { if (i2c_transfer(save_client->adapter, msgs, 2) < 0) goto read_err; sec1 = sec; min1 = min; hour1 = hour; day1 = day; mon1 = mon; year1 = year; sec = buf[m41t00_chip->sec] & 0x7f; min = buf[m41t00_chip->min] & 0x7f; hour = buf[m41t00_chip->hour] & 0x3f; day = buf[m41t00_chip->day] & 0x3f; mon = buf[m41t00_chip->mon] & 0x1f; year = buf[m41t00_chip->year]; } while ((++reads < m41t00_chip->read_limit) && ((sec != sec1) || (min != min1) || (hour != hour1) || (day != day1) || (mon != mon1) || (year != year1))); if ((m41t00_chip->read_limit > 1) && ((sec != sec1) || (min != min1) || (hour != hour1) || (day != day1) || (mon != mon1) || (year != year1))) goto read_err; sec = BCD2BIN(sec); min = BCD2BIN(min); hour = BCD2BIN(hour); day = BCD2BIN(day); mon = BCD2BIN(mon); year = BCD2BIN(year); year += 1900; if (year < 1970) year += 100; return mktime(year, mon, day, hour, min, sec); read_err: dev_err(&save_client->dev, "m41t00_get_rtc_time: Read error\n"); return 0; } EXPORT_SYMBOL_GPL(m41t00_get_rtc_time); static void m41t00_set(void *arg) { struct rtc_time tm; int nowtime = *(int *)arg; s32 sec, min, hour, day, mon, year; u8 wbuf[9], *buf = &wbuf[1], msgbuf[1] = { 0 }; struct i2c_msg msgs[] = { { .addr = save_client->addr, .flags = 0, .len = 1, .buf = msgbuf, }, { .addr = save_client->addr, .flags = I2C_M_RD, .len = 8, .buf = buf, }, }; to_tm(nowtime, &tm); tm.tm_year = (tm.tm_year - 1900) % 100; sec = BIN2BCD(tm.tm_sec); min = BIN2BCD(tm.tm_min); hour = BIN2BCD(tm.tm_hour); day = BIN2BCD(tm.tm_mday); mon = BIN2BCD(tm.tm_mon); year = BIN2BCD(tm.tm_year); /* Read reg values into buf[0..7]/wbuf[1..8] */ if (i2c_transfer(save_client->adapter, msgs, 2) < 0) { dev_err(&save_client->dev, "m41t00_set: Read error\n"); return; } wbuf[0] = 0; /* offset into rtc's regs */ buf[m41t00_chip->sec] = (buf[m41t00_chip->sec] & ~0x7f) | (sec & 0x7f); buf[m41t00_chip->min] = (buf[m41t00_chip->min] & ~0x7f) | (min & 0x7f); buf[m41t00_chip->hour] = (buf[m41t00_chip->hour] & ~0x3f) | (hour& 0x3f); buf[m41t00_chip->day] = (buf[m41t00_chip->day] & ~0x3f) | (day & 0x3f); buf[m41t00_chip->mon] = (buf[m41t00_chip->mon] & ~0x1f) | (mon & 0x1f); buf[m41t00_chip->year] = year; if (i2c_master_send(save_client, wbuf, 9) < 0) dev_err(&save_client->dev, "m41t00_set: Write error\n"); } static ulong new_time; /* well, isn't this API just _lovely_? */ static void m41t00_barf(struct work_struct *unusable) { m41t00_set(&new_time); } static struct workqueue_struct *m41t00_wq; static DECLARE_WORK(m41t00_work, m41t00_barf); int m41t00_set_rtc_time(ulong nowtime) { new_time = nowtime; if (in_interrupt()) queue_work(m41t00_wq, &m41t00_work); else m41t00_set(&new_time); return 0; } EXPORT_SYMBOL_GPL(m41t00_set_rtc_time); /* ***************************************************************************** * * platform_data Driver Interface * ***************************************************************************** */ static int __init m41t00_platform_probe(struct platform_device *pdev) { struct m41t00_platform_data *pdata; int i; if (pdev && (pdata = pdev->dev.platform_data)) { normal_addr[0] = pdata->i2c_addr; for (i=0; i<ARRAY_SIZE(m41t00_chip_info_tbl); i++) if (m41t00_chip_info_tbl[i].type == pdata->type) { m41t00_chip = &m41t00_chip_info_tbl[i]; m41t00_chip->sqw_freq = pdata->sqw_freq; return 0; } } return -ENODEV; } static int __exit m41t00_platform_remove(struct platform_device *pdev) { return 0; } static struct platform_driver m41t00_platform_driver = { .probe = m41t00_platform_probe, .remove = m41t00_platform_remove, .driver = { .owner = THIS_MODULE, .name = M41T00_DRV_NAME, }, }; /* ***************************************************************************** * * Driver Interface * ***************************************************************************** */ static int m41t00_probe(struct i2c_adapter *adap, int addr, int kind) { struct i2c_client *client; int rc; if (!i2c_check_functionality(adap, I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE_DATA)) return 0; client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL); if (!client) return -ENOMEM; strlcpy(client->name, m41t00_chip->name, I2C_NAME_SIZE); client->addr = addr; client->adapter = adap; client->driver = &m41t00_driver; if ((rc = i2c_attach_client(client))) goto attach_err; if (m41t00_chip->type != M41T00_TYPE_M41T00) { /* If asked, disable SQW, set SQW frequency & re-enable */ if (m41t00_chip->sqw_freq) if (((rc = i2c_smbus_read_byte_data(client, m41t00_chip->alarm_mon)) < 0) || ((rc = i2c_smbus_write_byte_data(client, m41t00_chip->alarm_mon, rc & ~0x40)) <0) || ((rc = i2c_smbus_write_byte_data(client, m41t00_chip->sqw, m41t00_chip->sqw_freq)) < 0) || ((rc = i2c_smbus_write_byte_data(client, m41t00_chip->alarm_mon, rc | 0x40)) <0)) goto sqw_err; /* Make sure HT (Halt Update) bit is cleared */ if ((rc = i2c_smbus_read_byte_data(client, m41t00_chip->alarm_hour)) < 0) goto ht_err; if (rc & 0x40) if ((rc = i2c_smbus_write_byte_data(client, m41t00_chip->alarm_hour, rc & ~0x40))<0) goto ht_err; } /* Make sure ST (stop) bit is cleared */ if ((rc = i2c_smbus_read_byte_data(client, m41t00_chip->sec)) < 0) goto st_err; if (rc & 0x80) if ((rc = i2c_smbus_write_byte_data(client, m41t00_chip->sec, rc & ~0x80)) < 0) goto st_err; m41t00_wq = create_singlethread_workqueue(m41t00_chip->name); save_client = client; return 0; st_err: dev_err(&client->dev, "m41t00_probe: Can't clear ST bit\n"); goto attach_err; ht_err: dev_err(&client->dev, "m41t00_probe: Can't clear HT bit\n"); goto attach_err; sqw_err: dev_err(&client->dev, "m41t00_probe: Can't set SQW Frequency\n"); attach_err: kfree(client); return rc; } 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); destroy_workqueue(m41t00_wq); } return rc; } static struct i2c_driver m41t00_driver = { .driver = { .name = M41T00_DRV_NAME, }, .id = I2C_DRIVERID_STM41T00, .attach_adapter = m41t00_attach, .detach_client = m41t00_detach, }; static int __init m41t00_init(void) { int rc; if (!(rc = platform_driver_register(&m41t00_platform_driver))) rc = i2c_add_driver(&m41t00_driver); return rc; } static void __exit m41t00_exit(void) { i2c_del_driver(&m41t00_driver); platform_driver_unregister(&m41t00_platform_driver); } 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");