// SPDX-License-Identifier: GPL-2.0-or-later /* * Seiko Instruments S-35390A RTC Driver * * Copyright (c) 2007 Byron Bradley */ #include <linux/module.h> #include <linux/rtc.h> #include <linux/i2c.h> #include <linux/bitrev.h> #include <linux/bcd.h> #include <linux/slab.h> #include <linux/delay.h> #define S35390A_CMD_STATUS1 0 #define S35390A_CMD_STATUS2 1 #define S35390A_CMD_TIME1 2 #define S35390A_CMD_TIME2 3 #define S35390A_CMD_INT2_REG1 5 #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_ALRM_BYTE_WDAY 0 #define S35390A_ALRM_BYTE_HOURS 1 #define S35390A_ALRM_BYTE_MINS 2 /* flags for STATUS1 */ #define S35390A_FLAG_POC BIT(0) #define S35390A_FLAG_BLD BIT(1) #define S35390A_FLAG_INT2 BIT(2) #define S35390A_FLAG_24H BIT(6) #define S35390A_FLAG_RESET BIT(7) /* flag for STATUS2 */ #define S35390A_FLAG_TEST BIT(0) /* INT2 pin output mode */ #define S35390A_INT2_MODE_MASK 0x0E #define S35390A_INT2_MODE_NOINTR 0x00 #define S35390A_INT2_MODE_ALARM BIT(1) /* INT2AE */ #define S35390A_INT2_MODE_PMIN_EDG BIT(2) /* INT2ME */ #define S35390A_INT2_MODE_FREQ BIT(3) /* INT2FE */ #define S35390A_INT2_MODE_PMIN (BIT(3) | BIT(2)) /* INT2FE | INT2ME */ static const struct i2c_device_id s35390a_id[] = { { "s35390a", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, s35390a_id); static const struct of_device_id s35390a_of_match[] = { { .compatible = "s35390a" }, { .compatible = "sii,s35390a" }, { } }; MODULE_DEVICE_TABLE(of, s35390a_of_match); 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[] = { { .addr = client->addr, .len = len, .buf = 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[] = { { .addr = client->addr, .flags = I2C_M_RD, .len = len, .buf = buf }, }; if ((i2c_transfer(client->adapter, msg, 1)) != 1) return -EIO; return 0; } static int s35390a_init(struct s35390a *s35390a) { u8 buf; int ret; unsigned initcount = 0; /* * At least one of POC and BLD are set, so reinitialise chip. Keeping * this information in the hardware to know later that the time isn't * valid is unfortunately not possible because POC and BLD are cleared * on read. So the reset is best done now. * * The 24H bit is kept over reset, so set it already here. */ initialize: buf = S35390A_FLAG_RESET | S35390A_FLAG_24H; ret = s35390a_set_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1); if (ret < 0) return ret; ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &buf, 1); if (ret < 0) return ret; if (buf & (S35390A_FLAG_POC | S35390A_FLAG_BLD)) { /* Try up to five times to reset the chip */ if (initcount < 5) { ++initcount; goto initialize; } else return -EIO; } return 1; } /* * Returns <0 on error, 0 if rtc is setup fine and 1 if the chip was reset. * To keep the information if an irq is pending, pass the value read from * STATUS1 to the caller. */ static int s35390a_read_status(struct s35390a *s35390a, char *status1) { int ret; ret = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, status1, 1); if (ret < 0) return ret; if (*status1 & S35390A_FLAG_POC) { /* * Do not communicate for 0.5 seconds since the power-on * detection circuit is in operation. */ msleep(500); return 1; } else if (*status1 & S35390A_FLAG_BLD) return 1; /* * If both POC and BLD are unset everything is fine. */ return 0; } 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_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); struct s35390a *s35390a = i2c_get_clientdata(client); int i, err; char buf[7], status; 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); if (s35390a_read_status(s35390a, &status) == 1) s35390a_init(s35390a); 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_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); struct s35390a *s35390a = i2c_get_clientdata(client); char buf[7], status; int i, err; if (s35390a_read_status(s35390a, &status) == 1) return -EINVAL; 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 0; } static int s35390a_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) { struct i2c_client *client = to_i2c_client(dev); struct s35390a *s35390a = i2c_get_clientdata(client); char buf[3], sts = 0; int err, i; dev_dbg(&client->dev, "%s: alm is secs=%d, mins=%d, hours=%d mday=%d, "\ "mon=%d, year=%d, wday=%d\n", __func__, alm->time.tm_sec, alm->time.tm_min, alm->time.tm_hour, alm->time.tm_mday, alm->time.tm_mon, alm->time.tm_year, alm->time.tm_wday); if (alm->time.tm_sec != 0) dev_warn(&client->dev, "Alarms are only supported on a per minute basis!\n"); /* disable interrupt (which deasserts the irq line) */ err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); if (err < 0) return err; /* clear pending interrupt (in STATUS1 only), if any */ err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS1, &sts, sizeof(sts)); if (err < 0) return err; if (alm->enabled) sts = S35390A_INT2_MODE_ALARM; else sts = S35390A_INT2_MODE_NOINTR; /* set interupt mode*/ err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); if (err < 0) return err; if (alm->time.tm_wday != -1) buf[S35390A_ALRM_BYTE_WDAY] = bin2bcd(alm->time.tm_wday) | 0x80; else buf[S35390A_ALRM_BYTE_WDAY] = 0; buf[S35390A_ALRM_BYTE_HOURS] = s35390a_hr2reg(s35390a, alm->time.tm_hour) | 0x80; buf[S35390A_ALRM_BYTE_MINS] = bin2bcd(alm->time.tm_min) | 0x80; if (alm->time.tm_hour >= 12) buf[S35390A_ALRM_BYTE_HOURS] |= 0x40; for (i = 0; i < 3; ++i) buf[i] = bitrev8(buf[i]); err = s35390a_set_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf)); return err; } static int s35390a_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) { struct i2c_client *client = to_i2c_client(dev); struct s35390a *s35390a = i2c_get_clientdata(client); char buf[3], sts; int i, err; err = s35390a_get_reg(s35390a, S35390A_CMD_STATUS2, &sts, sizeof(sts)); if (err < 0) return err; if ((sts & S35390A_INT2_MODE_MASK) != S35390A_INT2_MODE_ALARM) { /* * When the alarm isn't enabled, the register to configure * the alarm time isn't accessible. */ alm->enabled = 0; return 0; } else { alm->enabled = 1; } err = s35390a_get_reg(s35390a, S35390A_CMD_INT2_REG1, buf, sizeof(buf)); if (err < 0) return err; /* This chip returns the bits of each byte in reverse order */ for (i = 0; i < 3; ++i) buf[i] = bitrev8(buf[i]); /* * B0 of the three matching registers is an enable flag. Iff it is set * the configured value is used for matching. */ if (buf[S35390A_ALRM_BYTE_WDAY] & 0x80) alm->time.tm_wday = bcd2bin(buf[S35390A_ALRM_BYTE_WDAY] & ~0x80); if (buf[S35390A_ALRM_BYTE_HOURS] & 0x80) alm->time.tm_hour = s35390a_reg2hr(s35390a, buf[S35390A_ALRM_BYTE_HOURS] & ~0x80); if (buf[S35390A_ALRM_BYTE_MINS] & 0x80) alm->time.tm_min = bcd2bin(buf[S35390A_ALRM_BYTE_MINS] & ~0x80); /* alarm triggers always at s=0 */ alm->time.tm_sec = 0; dev_dbg(&client->dev, "%s: alm is mins=%d, hours=%d, wday=%d\n", __func__, alm->time.tm_min, alm->time.tm_hour, alm->time.tm_wday); return 0; } static int s35390a_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { struct i2c_client *client = to_i2c_client(dev); struct s35390a *s35390a = i2c_get_clientdata(client); char sts; int err; switch (cmd) { case RTC_VL_READ: /* s35390a_reset set lowvoltage flag and init RTC if needed */ err = s35390a_read_status(s35390a, &sts); if (err < 0) return err; if (copy_to_user((void __user *)arg, &err, sizeof(int))) return -EFAULT; break; case RTC_VL_CLR: /* update flag and clear register */ err = s35390a_init(s35390a); if (err < 0) return err; break; default: return -ENOIOCTLCMD; } return 0; } static const struct rtc_class_ops s35390a_rtc_ops = { .read_time = s35390a_rtc_read_time, .set_time = s35390a_rtc_set_time, .set_alarm = s35390a_rtc_set_alarm, .read_alarm = s35390a_rtc_read_alarm, .ioctl = s35390a_rtc_ioctl, }; static int s35390a_probe(struct i2c_client *client, const struct i2c_device_id *id) { int err, err_read; unsigned int i; struct s35390a *s35390a; char buf, status1; struct device *dev = &client->dev; if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) return -ENODEV; s35390a = devm_kzalloc(dev, sizeof(struct s35390a), GFP_KERNEL); if (!s35390a) return -ENOMEM; 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] = devm_i2c_new_dummy_device(dev, client->adapter, client->addr + i); if (IS_ERR(s35390a->client[i])) { dev_err(dev, "Address %02x unavailable\n", client->addr + i); return PTR_ERR(s35390a->client[i]); } } s35390a->rtc = devm_rtc_allocate_device(dev); if (IS_ERR(s35390a->rtc)) return PTR_ERR(s35390a->rtc); err_read = s35390a_read_status(s35390a, &status1); if (err_read < 0) { dev_err(dev, "error resetting chip\n"); return err_read; } if (status1 & S35390A_FLAG_24H) s35390a->twentyfourhour = 1; else s35390a->twentyfourhour = 0; if (status1 & S35390A_FLAG_INT2) { /* disable alarm (and maybe test mode) */ buf = 0; err = s35390a_set_reg(s35390a, S35390A_CMD_STATUS2, &buf, 1); if (err < 0) { dev_err(dev, "error disabling alarm"); return err; } } else { err = s35390a_disable_test_mode(s35390a); if (err < 0) { dev_err(dev, "error disabling test mode\n"); return err; } } device_set_wakeup_capable(dev, 1); s35390a->rtc->ops = &s35390a_rtc_ops; s35390a->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; s35390a->rtc->range_max = RTC_TIMESTAMP_END_2099; /* supports per-minute alarms only, therefore set uie_unsupported */ s35390a->rtc->uie_unsupported = 1; if (status1 & S35390A_FLAG_INT2) rtc_update_irq(s35390a->rtc, 1, RTC_AF); return rtc_register_device(s35390a->rtc); } static struct i2c_driver s35390a_driver = { .driver = { .name = "rtc-s35390a", .of_match_table = of_match_ptr(s35390a_of_match), }, .probe = s35390a_probe, .id_table = s35390a_id, }; module_i2c_driver(s35390a_driver); MODULE_AUTHOR("Byron Bradley <byron.bbradley@gmail.com>"); MODULE_DESCRIPTION("S35390A RTC driver"); MODULE_LICENSE("GPL");