diff options
Diffstat (limited to 'drivers/rtc/rtc-s35390a.c')
| -rw-r--r-- | drivers/rtc/rtc-s35390a.c | 316 |
1 files changed, 316 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-s35390a.c b/drivers/rtc/rtc-s35390a.c new file mode 100644 index 000000000000..e8abc90c32c5 --- /dev/null +++ b/drivers/rtc/rtc-s35390a.c @@ -0,0 +1,316 @@ +/* + * 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 + +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) +{ + 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, "rtc-s35390a"); + 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, +}; + +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); |