// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2012 Avionic Design GmbH */ #include <linux/bcd.h> #include <linux/i2c.h> #include <linux/module.h> #include <linux/rtc.h> #include <linux/of.h> #include <linux/pm_wakeirq.h> #define REG_CONTROL1 0x00 #define REG_CONTROL1_CAP_SEL BIT(7) #define REG_CONTROL1_STOP BIT(5) #define REG_CONTROL1_AIE BIT(1) #define REG_CONTROL2 0x01 #define REG_CONTROL2_AF BIT(3) #define REG_CONTROL3 0x02 #define REG_CONTROL3_PM_BLD BIT(7) /* battery low detection disabled */ #define REG_CONTROL3_PM_VDD BIT(6) /* switch-over disabled */ #define REG_CONTROL3_PM_DSM BIT(5) /* direct switching mode */ #define REG_CONTROL3_PM_MASK 0xe0 #define REG_CONTROL3_BLF BIT(2) /* battery low bit, read-only */ #define REG_SECONDS 0x03 #define REG_SECONDS_OS BIT(7) #define REG_MINUTES 0x04 #define REG_HOURS 0x05 #define REG_DAYS 0x06 #define REG_WEEKDAYS 0x07 #define REG_MONTHS 0x08 #define REG_YEARS 0x09 #define REG_MINUTE_ALARM 0x0a #define REG_HOUR_ALARM 0x0b #define REG_DAY_ALARM 0x0c #define REG_WEEKDAY_ALARM 0x0d #define ALARM_DIS BIT(7) #define REG_OFFSET 0x0e #define REG_OFFSET_MODE BIT(7) #define REG_TMR_CLKOUT_CTRL 0x0f struct pcf8523 { struct rtc_device *rtc; struct i2c_client *client; }; static int pcf8523_read(struct i2c_client *client, u8 reg, u8 *valuep) { struct i2c_msg msgs[2]; u8 value = 0; int err; msgs[0].addr = client->addr; msgs[0].flags = 0; msgs[0].len = sizeof(reg); msgs[0].buf = ® msgs[1].addr = client->addr; msgs[1].flags = I2C_M_RD; msgs[1].len = sizeof(value); msgs[1].buf = &value; err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); if (err < 0) return err; *valuep = value; return 0; } static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value) { u8 buffer[2] = { reg, value }; struct i2c_msg msg; int err; msg.addr = client->addr; msg.flags = 0; msg.len = sizeof(buffer); msg.buf = buffer; err = i2c_transfer(client->adapter, &msg, 1); if (err < 0) return err; return 0; } static int pcf8523_voltage_low(struct i2c_client *client) { u8 value; int err; err = pcf8523_read(client, REG_CONTROL3, &value); if (err < 0) return err; return !!(value & REG_CONTROL3_BLF); } static int pcf8523_load_capacitance(struct i2c_client *client) { u32 load; u8 value; int err; err = pcf8523_read(client, REG_CONTROL1, &value); if (err < 0) return err; load = 12500; of_property_read_u32(client->dev.of_node, "quartz-load-femtofarads", &load); switch (load) { default: dev_warn(&client->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500", load); fallthrough; case 12500: value |= REG_CONTROL1_CAP_SEL; break; case 7000: value &= ~REG_CONTROL1_CAP_SEL; break; } err = pcf8523_write(client, REG_CONTROL1, value); return err; } static int pcf8523_set_pm(struct i2c_client *client, u8 pm) { u8 value; int err; err = pcf8523_read(client, REG_CONTROL3, &value); if (err < 0) return err; value = (value & ~REG_CONTROL3_PM_MASK) | pm; err = pcf8523_write(client, REG_CONTROL3, value); if (err < 0) return err; return 0; } static irqreturn_t pcf8523_irq(int irq, void *dev_id) { struct pcf8523 *pcf8523 = i2c_get_clientdata(dev_id); u8 value; int err; err = pcf8523_read(pcf8523->client, REG_CONTROL2, &value); if (err < 0) return IRQ_HANDLED; if (value & REG_CONTROL2_AF) { value &= ~REG_CONTROL2_AF; pcf8523_write(pcf8523->client, REG_CONTROL2, value); rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF); return IRQ_HANDLED; } return IRQ_NONE; } static int pcf8523_stop_rtc(struct i2c_client *client) { u8 value; int err; err = pcf8523_read(client, REG_CONTROL1, &value); if (err < 0) return err; value |= REG_CONTROL1_STOP; err = pcf8523_write(client, REG_CONTROL1, value); if (err < 0) return err; return 0; } static int pcf8523_start_rtc(struct i2c_client *client) { u8 value; int err; err = pcf8523_read(client, REG_CONTROL1, &value); if (err < 0) return err; value &= ~REG_CONTROL1_STOP; err = pcf8523_write(client, REG_CONTROL1, value); if (err < 0) return err; return 0; } static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); u8 start = REG_SECONDS, regs[7]; struct i2c_msg msgs[2]; int err; err = pcf8523_voltage_low(client); if (err < 0) { return err; } else if (err > 0) { dev_err(dev, "low voltage detected, time is unreliable\n"); return -EINVAL; } msgs[0].addr = client->addr; msgs[0].flags = 0; msgs[0].len = 1; msgs[0].buf = &start; msgs[1].addr = client->addr; msgs[1].flags = I2C_M_RD; msgs[1].len = sizeof(regs); msgs[1].buf = regs; err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); if (err < 0) return err; if (regs[0] & REG_SECONDS_OS) return -EINVAL; tm->tm_sec = bcd2bin(regs[0] & 0x7f); tm->tm_min = bcd2bin(regs[1] & 0x7f); tm->tm_hour = bcd2bin(regs[2] & 0x3f); tm->tm_mday = bcd2bin(regs[3] & 0x3f); tm->tm_wday = regs[4] & 0x7; tm->tm_mon = bcd2bin(regs[5] & 0x1f) - 1; tm->tm_year = bcd2bin(regs[6]) + 100; return 0; } static int pcf8523_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct i2c_client *client = to_i2c_client(dev); struct i2c_msg msg; u8 regs[8]; int err; err = pcf8523_stop_rtc(client); if (err < 0) return err; regs[0] = REG_SECONDS; /* This will purposely overwrite REG_SECONDS_OS */ regs[1] = bin2bcd(tm->tm_sec); regs[2] = bin2bcd(tm->tm_min); regs[3] = bin2bcd(tm->tm_hour); regs[4] = bin2bcd(tm->tm_mday); regs[5] = tm->tm_wday; regs[6] = bin2bcd(tm->tm_mon + 1); regs[7] = bin2bcd(tm->tm_year - 100); msg.addr = client->addr; msg.flags = 0; msg.len = sizeof(regs); msg.buf = regs; err = i2c_transfer(client->adapter, &msg, 1); if (err < 0) { /* * If the time cannot be set, restart the RTC anyway. Note * that errors are ignored if the RTC cannot be started so * that we have a chance to propagate the original error. */ pcf8523_start_rtc(client); return err; } return pcf8523_start_rtc(client); } static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm) { struct i2c_client *client = to_i2c_client(dev); u8 start = REG_MINUTE_ALARM, regs[4]; struct i2c_msg msgs[2]; u8 value; int err; msgs[0].addr = client->addr; msgs[0].flags = 0; msgs[0].len = 1; msgs[0].buf = &start; msgs[1].addr = client->addr; msgs[1].flags = I2C_M_RD; msgs[1].len = sizeof(regs); msgs[1].buf = regs; err = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); if (err < 0) return err; tm->time.tm_sec = 0; tm->time.tm_min = bcd2bin(regs[0] & 0x7F); tm->time.tm_hour = bcd2bin(regs[1] & 0x3F); tm->time.tm_mday = bcd2bin(regs[2] & 0x3F); tm->time.tm_wday = bcd2bin(regs[3] & 0x7); err = pcf8523_read(client, REG_CONTROL1, &value); if (err < 0) return err; tm->enabled = !!(value & REG_CONTROL1_AIE); err = pcf8523_read(client, REG_CONTROL2, &value); if (err < 0) return err; tm->pending = !!(value & REG_CONTROL2_AF); return 0; } static int pcf8523_irq_enable(struct device *dev, unsigned int enabled) { struct i2c_client *client = to_i2c_client(dev); u8 value; int err; err = pcf8523_read(client, REG_CONTROL1, &value); if (err < 0) return err; value &= REG_CONTROL1_AIE; if (enabled) value |= REG_CONTROL1_AIE; err = pcf8523_write(client, REG_CONTROL1, value); if (err < 0) return err; return 0; } static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm) { struct i2c_client *client = to_i2c_client(dev); struct i2c_msg msg; u8 regs[5]; int err; err = pcf8523_irq_enable(dev, 0); if (err) return err; err = pcf8523_write(client, REG_CONTROL2, 0); if (err < 0) return err; /* The alarm has no seconds, round up to nearest minute */ if (tm->time.tm_sec) { time64_t alarm_time = rtc_tm_to_time64(&tm->time); alarm_time += 60 - tm->time.tm_sec; rtc_time64_to_tm(alarm_time, &tm->time); } regs[0] = REG_MINUTE_ALARM; regs[1] = bin2bcd(tm->time.tm_min); regs[2] = bin2bcd(tm->time.tm_hour); regs[3] = bin2bcd(tm->time.tm_mday); regs[4] = ALARM_DIS; msg.addr = client->addr; msg.flags = 0; msg.len = sizeof(regs); msg.buf = regs; err = i2c_transfer(client->adapter, &msg, 1); if (err < 0) return err; if (tm->enabled) return pcf8523_irq_enable(dev, tm->enabled); return 0; } #ifdef CONFIG_RTC_INTF_DEV static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { struct i2c_client *client = to_i2c_client(dev); unsigned int flags = 0; u8 value; int ret; switch (cmd) { case RTC_VL_READ: ret = pcf8523_voltage_low(client); if (ret < 0) return ret; if (ret) flags |= RTC_VL_BACKUP_LOW; ret = pcf8523_read(client, REG_SECONDS, &value); if (ret < 0) return ret; if (value & REG_SECONDS_OS) flags |= RTC_VL_DATA_INVALID; return put_user(flags, (unsigned int __user *)arg); default: return -ENOIOCTLCMD; } } #else #define pcf8523_rtc_ioctl NULL #endif static int pcf8523_rtc_read_offset(struct device *dev, long *offset) { struct i2c_client *client = to_i2c_client(dev); int err; u8 value; s8 val; err = pcf8523_read(client, REG_OFFSET, &value); if (err < 0) return err; /* sign extend the 7-bit offset value */ val = value << 1; *offset = (value & REG_OFFSET_MODE ? 4069 : 4340) * (val >> 1); return 0; } static int pcf8523_rtc_set_offset(struct device *dev, long offset) { struct i2c_client *client = to_i2c_client(dev); long reg_m0, reg_m1; u8 value; reg_m0 = clamp(DIV_ROUND_CLOSEST(offset, 4340), -64L, 63L); reg_m1 = clamp(DIV_ROUND_CLOSEST(offset, 4069), -64L, 63L); if (abs(reg_m0 * 4340 - offset) < abs(reg_m1 * 4069 - offset)) value = reg_m0 & 0x7f; else value = (reg_m1 & 0x7f) | REG_OFFSET_MODE; return pcf8523_write(client, REG_OFFSET, value); } static const struct rtc_class_ops pcf8523_rtc_ops = { .read_time = pcf8523_rtc_read_time, .set_time = pcf8523_rtc_set_time, .read_alarm = pcf8523_rtc_read_alarm, .set_alarm = pcf8523_rtc_set_alarm, .alarm_irq_enable = pcf8523_irq_enable, .ioctl = pcf8523_rtc_ioctl, .read_offset = pcf8523_rtc_read_offset, .set_offset = pcf8523_rtc_set_offset, }; static int pcf8523_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct pcf8523 *pcf8523; struct rtc_device *rtc; bool wakeup_source = false; int err; if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) return -ENODEV; pcf8523 = devm_kzalloc(&client->dev, sizeof(struct pcf8523), GFP_KERNEL); if (!pcf8523) return -ENOMEM; i2c_set_clientdata(client, pcf8523); pcf8523->client = client; err = pcf8523_load_capacitance(client); if (err < 0) dev_warn(&client->dev, "failed to set xtal load capacitance: %d", err); err = pcf8523_set_pm(client, 0); if (err < 0) return err; rtc = devm_rtc_allocate_device(&client->dev); if (IS_ERR(rtc)) return PTR_ERR(rtc); pcf8523->rtc = rtc; rtc->ops = &pcf8523_rtc_ops; rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; rtc->range_max = RTC_TIMESTAMP_END_2099; rtc->uie_unsupported = 1; if (client->irq > 0) { err = pcf8523_write(client, REG_TMR_CLKOUT_CTRL, 0x38); if (err < 0) return err; err = devm_request_threaded_irq(&client->dev, client->irq, NULL, pcf8523_irq, IRQF_SHARED | IRQF_ONESHOT | IRQF_TRIGGER_LOW, dev_name(&rtc->dev), client); if (err) return err; dev_pm_set_wake_irq(&client->dev, client->irq); } #ifdef CONFIG_OF wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source"); #endif if (client->irq > 0 || wakeup_source) device_init_wakeup(&client->dev, true); return devm_rtc_register_device(rtc); } static const struct i2c_device_id pcf8523_id[] = { { "pcf8523", 0 }, { } }; MODULE_DEVICE_TABLE(i2c, pcf8523_id); #ifdef CONFIG_OF static const struct of_device_id pcf8523_of_match[] = { { .compatible = "nxp,pcf8523" }, { .compatible = "microcrystal,rv8523" }, { } }; MODULE_DEVICE_TABLE(of, pcf8523_of_match); #endif static struct i2c_driver pcf8523_driver = { .driver = { .name = "rtc-pcf8523", .of_match_table = of_match_ptr(pcf8523_of_match), }, .probe = pcf8523_probe, .id_table = pcf8523_id, }; module_i2c_driver(pcf8523_driver); MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>"); MODULE_DESCRIPTION("NXP PCF8523 RTC driver"); MODULE_LICENSE("GPL v2");