/* * Seiko Instruments S-35390A RTC Driver * * Copyright (c) 2007 Byron Bradley * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/module.h> #include <linux/rtc.h> #include <linux/i2c.h> #include <linux/bitrev.h> #include <linux/bcd.h> #include <linux/slab.h> #define S35390A_CMD_STATUS1 0 #define S35390A_CMD_STATUS2 1 #define S35390A_CMD_TIME1 2 #define S35390A_BYTE_YEAR 0 #define S35390A_BYTE_MONTH 1 #define S35390A_BYTE_DAY 2 #define S35390A_BYTE_WDAY 3 #define S35390A_BYTE_HOURS 4 #define S35390A_BYTE_MINS 5 #define S35390A_BYTE_SECS 6 #define S35390A_FLAG_POC 0x01 #define S35390A_FLAG_BLD 0x02 #define S35390A_FLAG_24H 0x40 #define S35390A_FLAG_RESET 0x80 #define S35390A_FLAG_TEST 0x01 static const struct i2c_device_id s35390a_id[] = { { "s35390a", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, s35390a_id); struct s35390a { struct i2c_client *client[8]; struct rtc_device *rtc; int twentyfourhour; }; static int s35390a_set_reg(struct s35390a *s35390a, int reg, char *buf, int len) { struct i2c_client *client = s35390a->client[reg]; struct i2c_msg msg[] = { { client->addr, 0, len, buf }, }; if ((i2c_transfer(client->adapter, msg, 1)) != 1) return -EIO; return 0; } static int s35390a_get_reg(struct s35390a *s35390a, int reg, char *buf, int len) { struct i2c_client *client = s35390a->client[reg]; struct i2c_msg msg[] = { { client->addr, I2C_M_RD, len, buf }, }; if ((i2c_transfer(client->adapter, msg, 1)) != 1) return -EIO; return 0; } static int s35390a_reset(struct s35390a *s35390a) { char buf[1]; if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)) < 0) return -EIO; if (!(buf[0] & (S35390A_FLAG_POC | S35390A_FLAG_BLD))) return 0; buf[0] |= (S35390A_FLAG_RESET | S35390A_FLAG_24H); buf[0] &= 0xf0; return s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)); } static int s35390a_disable_test_mode(struct s35390a *s35390a) { char buf[1]; if (s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)) < 0) return -EIO; if (!(buf[0] & S35390A_FLAG_TEST)) return 0; buf[0] &= ~S35390A_FLAG_TEST; return s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, buf, sizeof(buf)); } static char s35390a_hr2reg(struct s35390a *s35390a, int hour) { if (s35390a->twentyfourhour) return bin2bcd(hour); if (hour < 12) return bin2bcd(hour); return 0x40 | bin2bcd(hour - 12); } static int s35390a_reg2hr(struct s35390a *s35390a, char reg) { unsigned hour; if (s35390a->twentyfourhour) return bcd2bin(reg & 0x3f); hour = bcd2bin(reg & 0x3f); if (reg & 0x40) hour += 12; return hour; } static int s35390a_set_datetime(struct i2c_client *client, struct rtc_time *tm) { struct s35390a *s35390a = i2c_get_clientdata(client); int i, err; char buf[7]; dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d mday=%d, " "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); buf[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 100); buf[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon + 1); buf[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday); buf[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday); buf[S35390A_BYTE_HOURS] = s35390a_hr2reg(s35390a, tm->tm_hour); buf[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min); buf[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec); /* This chip expects the bits of each byte to be in reverse order */ for (i = 0; i < 7; ++i) buf[i] = bitrev8(buf[i]); err = s35390a_set_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); return err; } static int s35390a_get_datetime(struct i2c_client *client, struct rtc_time *tm) { struct s35390a *s35390a = i2c_get_clientdata(client); char buf[7]; int i, err; err = s35390a_get_reg(s35390a, S35390A_CMD_TIME1, buf, sizeof(buf)); if (err < 0) return err; /* This chip returns the bits of each byte in reverse order */ for (i = 0; i < 7; ++i) buf[i] = bitrev8(buf[i]); tm->tm_sec = bcd2bin(buf[S35390A_BYTE_SECS]); tm->tm_min = bcd2bin(buf[S35390A_BYTE_MINS]); tm->tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_BYTE_HOURS]); tm->tm_wday = bcd2bin(buf[S35390A_BYTE_WDAY]); tm->tm_mday = bcd2bin(buf[S35390A_BYTE_DAY]); tm->tm_mon = bcd2bin(buf[S35390A_BYTE_MONTH]) - 1; tm->tm_year = bcd2bin(buf[S35390A_BYTE_YEAR]) + 100; dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, mday=%d, " "mon=%d, year=%d, wday=%d\n", __func__, tm->tm_sec, tm->tm_min, tm->tm_hour, tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); return rtc_valid_tm(tm); } static int s35390a_rtc_read_time(struct device *dev, struct rtc_time *tm) { return s35390a_get_datetime(to_i2c_client(dev), tm); } static int s35390a_rtc_set_time(struct device *dev, struct rtc_time *tm) { return s35390a_set_datetime(to_i2c_client(dev), tm); } static const struct rtc_class_ops s35390a_rtc_ops = { .read_time = s35390a_rtc_read_time, .set_time = s35390a_rtc_set_time, }; static struct i2c_driver s35390a_driver; static int s35390a_probe(struct i2c_client *client, const struct i2c_device_id *id) { int err; unsigned int i; struct s35390a *s35390a; struct rtc_time tm; char buf[1]; if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { err = -ENODEV; goto exit; } s35390a = kzalloc(sizeof(struct s35390a), GFP_KERNEL); if (!s35390a) { err = -ENOMEM; goto exit; } s35390a->client[0] = client; i2c_set_clientdata(client, s35390a); /* This chip uses multiple addresses, use dummy devices for them */ for (i = 1; i < 8; ++i) { s35390a->client[i] = i2c_new_dummy(client->adapter, client->addr + i); if (!s35390a->client[i]) { dev_err(&client->dev, "Address %02x unavailable\n", client->addr + i); err = -EBUSY; goto exit_dummy; } } err = s35390a_reset(s35390a); if (err < 0) { dev_err(&client->dev, "error resetting chip\n"); goto exit_dummy; } err = s35390a_disable_test_mode(s35390a); if (err < 0) { dev_err(&client->dev, "error disabling test mode\n"); goto exit_dummy; } err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, buf, sizeof(buf)); if (err < 0) { dev_err(&client->dev, "error checking 12/24 hour mode\n"); goto exit_dummy; } if (buf[0] & S35390A_FLAG_24H) s35390a->twentyfourhour = 1; else s35390a->twentyfourhour = 0; if (s35390a_get_datetime(client, &tm) < 0) dev_warn(&client->dev, "clock needs to be set\n"); s35390a->rtc = rtc_device_register(s35390a_driver.driver.name, &client->dev, &s35390a_rtc_ops, THIS_MODULE); if (IS_ERR(s35390a->rtc)) { err = PTR_ERR(s35390a->rtc); goto exit_dummy; } return 0; exit_dummy: for (i = 1; i < 8; ++i) if (s35390a->client[i]) i2c_unregister_device(s35390a->client[i]); kfree(s35390a); i2c_set_clientdata(client, NULL); exit: return err; } static int s35390a_remove(struct i2c_client *client) { unsigned int i; struct s35390a *s35390a = i2c_get_clientdata(client); for (i = 1; i < 8; ++i) if (s35390a->client[i]) i2c_unregister_device(s35390a->client[i]); rtc_device_unregister(s35390a->rtc); kfree(s35390a); i2c_set_clientdata(client, NULL); return 0; } static struct i2c_driver s35390a_driver = { .driver = { .name = "rtc-s35390a", }, .probe = s35390a_probe, .remove = s35390a_remove, .id_table = s35390a_id, }; static int __init s35390a_rtc_init(void) { return i2c_add_driver(&s35390a_driver); } static void __exit s35390a_rtc_exit(void) { i2c_del_driver(&s35390a_driver); } MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>"); MODULE_DESCRIPTION("S35390A RTC driver"); MODULE_LICENSE("GPL"); module_init(s35390a_rtc_init); module_exit(s35390a_rtc_exit);