// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (C) 2012 Avionic Design GmbH */ #include <linux/bcd.h> #include <linux/bitfield.h> #include <linux/i2c.h> #include <linux/module.h> #include <linux/regmap.h> #include <linux/rtc.h> #include <linux/of.h> #include <linux/pm_wakeirq.h> #define PCF8523_REG_CONTROL1 0x00 #define PCF8523_CONTROL1_CAP_SEL BIT(7) #define PCF8523_CONTROL1_STOP BIT(5) #define PCF8523_CONTROL1_AIE BIT(1) #define PCF8523_REG_CONTROL2 0x01 #define PCF8523_CONTROL2_AF BIT(3) #define PCF8523_REG_CONTROL3 0x02 #define PCF8523_CONTROL3_PM GENMASK(7,5) #define PCF8523_PM_STANDBY 0x7 #define PCF8523_CONTROL3_BLF BIT(2) /* battery low bit, read-only */ #define PCF8523_CONTROL3_BSF BIT(3) #define PCF8523_REG_SECONDS 0x03 #define PCF8523_SECONDS_OS BIT(7) #define PCF8523_REG_MINUTES 0x04 #define PCF8523_REG_HOURS 0x05 #define PCF8523_REG_DAYS 0x06 #define PCF8523_REG_WEEKDAYS 0x07 #define PCF8523_REG_MONTHS 0x08 #define PCF8523_REG_YEARS 0x09 #define PCF8523_REG_MINUTE_ALARM 0x0a #define PCF8523_REG_HOUR_ALARM 0x0b #define PCF8523_REG_DAY_ALARM 0x0c #define PCF8523_REG_WEEKDAY_ALARM 0x0d #define ALARM_DIS BIT(7) #define PCF8523_REG_OFFSET 0x0e #define PCF8523_OFFSET_MODE BIT(7) #define PCF8523_TMR_CLKOUT_CTRL 0x0f struct pcf8523 { struct rtc_device *rtc; struct regmap *regmap; }; static int pcf8523_load_capacitance(struct pcf8523 *pcf8523, struct device_node *node) { u32 load, value = 0; load = 12500; of_property_read_u32(node, "quartz-load-femtofarads", &load); switch (load) { default: dev_warn(&pcf8523->rtc->dev, "Unknown quartz-load-femtofarads value: %d. Assuming 12500", load); fallthrough; case 12500: value |= PCF8523_CONTROL1_CAP_SEL; break; case 7000: break; } return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1, PCF8523_CONTROL1_CAP_SEL, value); } static irqreturn_t pcf8523_irq(int irq, void *dev_id) { struct pcf8523 *pcf8523 = dev_id; u32 value; int err; err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value); if (err < 0) return IRQ_HANDLED; if (value & PCF8523_CONTROL2_AF) { value &= ~PCF8523_CONTROL2_AF; regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, value); rtc_update_irq(pcf8523->rtc, 1, RTC_IRQF | RTC_AF); return IRQ_HANDLED; } return IRQ_NONE; } static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct pcf8523 *pcf8523 = dev_get_drvdata(dev); u8 regs[7]; int err; err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_SECONDS, regs, sizeof(regs)); if (err < 0) return err; if (regs[0] & PCF8523_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 pcf8523 *pcf8523 = dev_get_drvdata(dev); u8 regs[7]; int err; err = regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1, PCF8523_CONTROL1_STOP, PCF8523_CONTROL1_STOP); if (err < 0) return err; /* This will purposely overwrite PCF8523_SECONDS_OS */ regs[0] = bin2bcd(tm->tm_sec); regs[1] = bin2bcd(tm->tm_min); regs[2] = bin2bcd(tm->tm_hour); regs[3] = bin2bcd(tm->tm_mday); regs[4] = tm->tm_wday; regs[5] = bin2bcd(tm->tm_mon + 1); regs[6] = bin2bcd(tm->tm_year - 100); err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_SECONDS, regs, sizeof(regs)); 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. */ regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1, PCF8523_CONTROL1_STOP, 0); return err; } return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1, PCF8523_CONTROL1_STOP, 0); } static int pcf8523_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *tm) { struct pcf8523 *pcf8523 = dev_get_drvdata(dev); u8 regs[4]; u32 value; int err; err = regmap_bulk_read(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs, sizeof(regs)); 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 = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL1, &value); if (err < 0) return err; tm->enabled = !!(value & PCF8523_CONTROL1_AIE); err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL2, &value); if (err < 0) return err; tm->pending = !!(value & PCF8523_CONTROL2_AF); return 0; } static int pcf8523_irq_enable(struct device *dev, unsigned int enabled) { struct pcf8523 *pcf8523 = dev_get_drvdata(dev); return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL1, PCF8523_CONTROL1_AIE, enabled ? PCF8523_CONTROL1_AIE : 0); } static int pcf8523_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *tm) { struct pcf8523 *pcf8523 = dev_get_drvdata(dev); u8 regs[5]; int err; err = pcf8523_irq_enable(dev, 0); if (err) return err; err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL2, 0); if (err < 0) return err; regs[0] = bin2bcd(tm->time.tm_min); regs[1] = bin2bcd(tm->time.tm_hour); regs[2] = bin2bcd(tm->time.tm_mday); regs[3] = ALARM_DIS; err = regmap_bulk_write(pcf8523->regmap, PCF8523_REG_MINUTE_ALARM, regs, sizeof(regs)); if (err < 0) return err; if (tm->enabled) return pcf8523_irq_enable(dev, tm->enabled); return 0; } static int pcf8523_param_get(struct device *dev, struct rtc_param *param) { struct pcf8523 *pcf8523 = dev_get_drvdata(dev); int ret; u32 value; switch(param->param) { case RTC_PARAM_BACKUP_SWITCH_MODE: ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value); if (ret < 0) return ret; value = FIELD_GET(PCF8523_CONTROL3_PM, value); switch(value) { case 0x0: case 0x4: param->uvalue = RTC_BSM_LEVEL; break; case 0x1: case 0x5: param->uvalue = RTC_BSM_DIRECT; break; case PCF8523_PM_STANDBY: param->uvalue = RTC_BSM_STANDBY; break; default: param->uvalue = RTC_BSM_DISABLED; } break; default: return -EINVAL; } return 0; } static int pcf8523_param_set(struct device *dev, struct rtc_param *param) { struct pcf8523 *pcf8523 = dev_get_drvdata(dev); u8 mode; switch(param->param) { case RTC_PARAM_BACKUP_SWITCH_MODE: switch (param->uvalue) { case RTC_BSM_DISABLED: mode = 0x2; break; case RTC_BSM_DIRECT: mode = 0x1; break; case RTC_BSM_LEVEL: mode = 0x0; break; case RTC_BSM_STANDBY: mode = PCF8523_PM_STANDBY; break; default: return -EINVAL; } return regmap_update_bits(pcf8523->regmap, PCF8523_REG_CONTROL3, PCF8523_CONTROL3_PM, FIELD_PREP(PCF8523_CONTROL3_PM, mode)); break; default: return -EINVAL; } return 0; } static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { struct pcf8523 *pcf8523 = dev_get_drvdata(dev); unsigned int flags = 0; u32 value; int ret; switch (cmd) { case RTC_VL_READ: ret = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value); if (ret < 0) return ret; if (value & PCF8523_CONTROL3_BLF) flags |= RTC_VL_BACKUP_LOW; ret = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value); if (ret < 0) return ret; if (value & PCF8523_SECONDS_OS) flags |= RTC_VL_DATA_INVALID; return put_user(flags, (unsigned int __user *)arg); default: return -ENOIOCTLCMD; } } static int pcf8523_rtc_read_offset(struct device *dev, long *offset) { struct pcf8523 *pcf8523 = dev_get_drvdata(dev); int err; u32 value; s8 val; err = regmap_read(pcf8523->regmap, PCF8523_REG_OFFSET, &value); if (err < 0) return err; /* sign extend the 7-bit offset value */ val = value << 1; *offset = (value & PCF8523_OFFSET_MODE ? 4069 : 4340) * (val >> 1); return 0; } static int pcf8523_rtc_set_offset(struct device *dev, long offset) { struct pcf8523 *pcf8523 = dev_get_drvdata(dev); long reg_m0, reg_m1; u32 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) | PCF8523_OFFSET_MODE; return regmap_write(pcf8523->regmap, PCF8523_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, .param_get = pcf8523_param_get, .param_set = pcf8523_param_set, }; static const struct regmap_config regmap_config = { .reg_bits = 8, .val_bits = 8, .max_register = 0x13, }; static int pcf8523_probe(struct i2c_client *client) { struct pcf8523 *pcf8523; struct rtc_device *rtc; bool wakeup_source = false; u32 value; 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; pcf8523->regmap = devm_regmap_init_i2c(client, ®map_config); if (IS_ERR(pcf8523->regmap)) return PTR_ERR(pcf8523->regmap); i2c_set_clientdata(client, pcf8523); rtc = devm_rtc_allocate_device(&client->dev); if (IS_ERR(rtc)) return PTR_ERR(rtc); pcf8523->rtc = rtc; err = pcf8523_load_capacitance(pcf8523, client->dev.of_node); if (err < 0) dev_warn(&client->dev, "failed to set xtal load capacitance: %d", err); err = regmap_read(pcf8523->regmap, PCF8523_REG_SECONDS, &value); if (err < 0) return err; if (value & PCF8523_SECONDS_OS) { err = regmap_read(pcf8523->regmap, PCF8523_REG_CONTROL3, &value); if (err < 0) return err; if (FIELD_GET(PCF8523_CONTROL3_PM, value) == PCF8523_PM_STANDBY) { err = regmap_write(pcf8523->regmap, PCF8523_REG_CONTROL3, value & ~PCF8523_CONTROL3_PM); if (err < 0) return err; } } rtc->ops = &pcf8523_rtc_ops; rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; rtc->range_max = RTC_TIMESTAMP_END_2099; set_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features); clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features); if (client->irq > 0) { err = regmap_write(pcf8523->regmap, PCF8523_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), pcf8523); if (err) return err; dev_pm_set_wake_irq(&client->dev, client->irq); } wakeup_source = of_property_read_bool(client->dev.of_node, "wakeup-source"); 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); static const struct of_device_id pcf8523_of_match[] = { { .compatible = "nxp,pcf8523" }, { .compatible = "microcrystal,rv8523" }, { } }; MODULE_DEVICE_TABLE(of, pcf8523_of_match); static struct i2c_driver pcf8523_driver = { .driver = { .name = "rtc-pcf8523", .of_match_table = pcf8523_of_match, }, .probe_new = 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");