diff options
Diffstat (limited to 'drivers/rtc/rtc-rv8803.c')
| -rw-r--r-- | drivers/rtc/rtc-rv8803.c | 748 |
1 files changed, 748 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c new file mode 100644 index 0000000000..1a3ec1bb5b --- /dev/null +++ b/drivers/rtc/rtc-rv8803.c @@ -0,0 +1,748 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * RTC driver for the Micro Crystal RV8803 + * + * Copyright (C) 2015 Micro Crystal SA + * Alexandre Belloni <alexandre.belloni@bootlin.com> + * + */ + +#include <linux/bcd.h> +#include <linux/bitops.h> +#include <linux/bitfield.h> +#include <linux/log2.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/rtc.h> + +#define RV8803_I2C_TRY_COUNT 4 + +#define RV8803_SEC 0x00 +#define RV8803_MIN 0x01 +#define RV8803_HOUR 0x02 +#define RV8803_WEEK 0x03 +#define RV8803_DAY 0x04 +#define RV8803_MONTH 0x05 +#define RV8803_YEAR 0x06 +#define RV8803_RAM 0x07 +#define RV8803_ALARM_MIN 0x08 +#define RV8803_ALARM_HOUR 0x09 +#define RV8803_ALARM_WEEK_OR_DAY 0x0A +#define RV8803_EXT 0x0D +#define RV8803_FLAG 0x0E +#define RV8803_CTRL 0x0F +#define RV8803_OSC_OFFSET 0x2C + +#define RV8803_EXT_WADA BIT(6) + +#define RV8803_FLAG_V1F BIT(0) +#define RV8803_FLAG_V2F BIT(1) +#define RV8803_FLAG_AF BIT(3) +#define RV8803_FLAG_TF BIT(4) +#define RV8803_FLAG_UF BIT(5) + +#define RV8803_CTRL_RESET BIT(0) + +#define RV8803_CTRL_EIE BIT(2) +#define RV8803_CTRL_AIE BIT(3) +#define RV8803_CTRL_TIE BIT(4) +#define RV8803_CTRL_UIE BIT(5) + +#define RX8803_CTRL_CSEL GENMASK(7, 6) + +#define RX8900_BACKUP_CTRL 0x18 +#define RX8900_FLAG_SWOFF BIT(2) +#define RX8900_FLAG_VDETOFF BIT(3) + +enum rv8803_type { + rv_8803, + rx_8803, + rx_8804, + rx_8900 +}; + +struct rv8803_data { + struct i2c_client *client; + struct rtc_device *rtc; + struct mutex flags_lock; + u8 ctrl; + u8 backup; + u8 alarm_invalid:1; + enum rv8803_type type; +}; + +static int rv8803_read_reg(const struct i2c_client *client, u8 reg) +{ + int try = RV8803_I2C_TRY_COUNT; + s32 ret; + + /* + * There is a 61µs window during which the RTC does not acknowledge I2C + * transfers. In that case, ensure that there are multiple attempts. + */ + do + ret = i2c_smbus_read_byte_data(client, reg); + while ((ret == -ENXIO || ret == -EIO) && --try); + if (ret < 0) + dev_err(&client->dev, "Unable to read register 0x%02x\n", reg); + + return ret; +} + +static int rv8803_read_regs(const struct i2c_client *client, + u8 reg, u8 count, u8 *values) +{ + int try = RV8803_I2C_TRY_COUNT; + s32 ret; + + do + ret = i2c_smbus_read_i2c_block_data(client, reg, count, values); + while ((ret == -ENXIO || ret == -EIO) && --try); + if (ret != count) { + dev_err(&client->dev, + "Unable to read registers 0x%02x..0x%02x\n", + reg, reg + count - 1); + return ret < 0 ? ret : -EIO; + } + + return 0; +} + +static int rv8803_write_reg(const struct i2c_client *client, u8 reg, u8 value) +{ + int try = RV8803_I2C_TRY_COUNT; + s32 ret; + + do + ret = i2c_smbus_write_byte_data(client, reg, value); + while ((ret == -ENXIO || ret == -EIO) && --try); + if (ret) + dev_err(&client->dev, "Unable to write register 0x%02x\n", reg); + + return ret; +} + +static int rv8803_write_regs(const struct i2c_client *client, + u8 reg, u8 count, const u8 *values) +{ + int try = RV8803_I2C_TRY_COUNT; + s32 ret; + + do + ret = i2c_smbus_write_i2c_block_data(client, reg, count, + values); + while ((ret == -ENXIO || ret == -EIO) && --try); + if (ret) + dev_err(&client->dev, + "Unable to write registers 0x%02x..0x%02x\n", + reg, reg + count - 1); + + return ret; +} + +static int rv8803_regs_init(struct rv8803_data *rv8803) +{ + int ret; + + ret = rv8803_write_reg(rv8803->client, RV8803_OSC_OFFSET, 0x00); + if (ret) + return ret; + + ret = rv8803_write_reg(rv8803->client, RV8803_CTRL, + FIELD_PREP(RX8803_CTRL_CSEL, 1)); /* 2s */ + if (ret) + return ret; + + ret = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, + (u8[]){ 0, 0, 0 }); + if (ret) + return ret; + + return rv8803_write_reg(rv8803->client, RV8803_RAM, 0x00); +} + +static int rv8803_regs_configure(struct rv8803_data *rv8803); + +static int rv8803_regs_reset(struct rv8803_data *rv8803, bool full) +{ + /* + * The RV-8803 resets all registers to POR defaults after voltage-loss, + * the Epson RTCs don't, so we manually reset the remainder here. + */ + if (full || rv8803->type == rx_8803 || rv8803->type == rx_8900) { + int ret = rv8803_regs_init(rv8803); + if (ret) + return ret; + } + + return rv8803_regs_configure(rv8803); +} + +static irqreturn_t rv8803_handle_irq(int irq, void *dev_id) +{ + struct i2c_client *client = dev_id; + struct rv8803_data *rv8803 = i2c_get_clientdata(client); + unsigned long events = 0; + int flags; + + mutex_lock(&rv8803->flags_lock); + + flags = rv8803_read_reg(client, RV8803_FLAG); + if (flags <= 0) { + mutex_unlock(&rv8803->flags_lock); + return IRQ_NONE; + } + + if (flags & RV8803_FLAG_V1F) + dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); + + if (flags & RV8803_FLAG_V2F) + dev_warn(&client->dev, "Voltage low, data loss detected.\n"); + + if (flags & RV8803_FLAG_TF) { + flags &= ~RV8803_FLAG_TF; + rv8803->ctrl &= ~RV8803_CTRL_TIE; + events |= RTC_PF; + } + + if (flags & RV8803_FLAG_AF) { + flags &= ~RV8803_FLAG_AF; + rv8803->ctrl &= ~RV8803_CTRL_AIE; + events |= RTC_AF; + } + + if (flags & RV8803_FLAG_UF) { + flags &= ~RV8803_FLAG_UF; + rv8803->ctrl &= ~RV8803_CTRL_UIE; + events |= RTC_UF; + } + + if (events) { + rtc_update_irq(rv8803->rtc, 1, events); + rv8803_write_reg(client, RV8803_FLAG, flags); + rv8803_write_reg(rv8803->client, RV8803_CTRL, rv8803->ctrl); + } + + mutex_unlock(&rv8803->flags_lock); + + return IRQ_HANDLED; +} + +static int rv8803_get_time(struct device *dev, struct rtc_time *tm) +{ + struct rv8803_data *rv8803 = dev_get_drvdata(dev); + u8 date1[7]; + u8 date2[7]; + u8 *date = date1; + int ret, flags; + + if (rv8803->alarm_invalid) { + dev_warn(dev, "Corruption detected, data may be invalid.\n"); + return -EINVAL; + } + + flags = rv8803_read_reg(rv8803->client, RV8803_FLAG); + if (flags < 0) + return flags; + + if (flags & RV8803_FLAG_V2F) { + dev_warn(dev, "Voltage low, data is invalid.\n"); + return -EINVAL; + } + + ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date); + if (ret) + return ret; + + if ((date1[RV8803_SEC] & 0x7f) == bin2bcd(59)) { + ret = rv8803_read_regs(rv8803->client, RV8803_SEC, 7, date2); + if (ret) + return ret; + + if ((date2[RV8803_SEC] & 0x7f) != bin2bcd(59)) + date = date2; + } + + tm->tm_sec = bcd2bin(date[RV8803_SEC] & 0x7f); + tm->tm_min = bcd2bin(date[RV8803_MIN] & 0x7f); + tm->tm_hour = bcd2bin(date[RV8803_HOUR] & 0x3f); + tm->tm_wday = ilog2(date[RV8803_WEEK] & 0x7f); + tm->tm_mday = bcd2bin(date[RV8803_DAY] & 0x3f); + tm->tm_mon = bcd2bin(date[RV8803_MONTH] & 0x1f) - 1; + tm->tm_year = bcd2bin(date[RV8803_YEAR]) + 100; + + return 0; +} + +static int rv8803_set_time(struct device *dev, struct rtc_time *tm) +{ + struct rv8803_data *rv8803 = dev_get_drvdata(dev); + u8 date[7]; + int ctrl, flags, ret; + + ctrl = rv8803_read_reg(rv8803->client, RV8803_CTRL); + if (ctrl < 0) + return ctrl; + + /* Stop the clock */ + ret = rv8803_write_reg(rv8803->client, RV8803_CTRL, + ctrl | RV8803_CTRL_RESET); + if (ret) + return ret; + + date[RV8803_SEC] = bin2bcd(tm->tm_sec); + date[RV8803_MIN] = bin2bcd(tm->tm_min); + date[RV8803_HOUR] = bin2bcd(tm->tm_hour); + date[RV8803_WEEK] = 1 << (tm->tm_wday); + date[RV8803_DAY] = bin2bcd(tm->tm_mday); + date[RV8803_MONTH] = bin2bcd(tm->tm_mon + 1); + date[RV8803_YEAR] = bin2bcd(tm->tm_year - 100); + + ret = rv8803_write_regs(rv8803->client, RV8803_SEC, 7, date); + if (ret) + return ret; + + /* Restart the clock */ + ret = rv8803_write_reg(rv8803->client, RV8803_CTRL, + ctrl & ~RV8803_CTRL_RESET); + if (ret) + return ret; + + mutex_lock(&rv8803->flags_lock); + + flags = rv8803_read_reg(rv8803->client, RV8803_FLAG); + if (flags < 0) { + mutex_unlock(&rv8803->flags_lock); + return flags; + } + + if ((flags & RV8803_FLAG_V2F) || rv8803->alarm_invalid) { + /* + * If we sense corruption in the alarm registers, but see no + * voltage loss flag, we can't rely on other registers having + * sensible values. Reset them fully. + */ + ret = rv8803_regs_reset(rv8803, rv8803->alarm_invalid); + if (ret) { + mutex_unlock(&rv8803->flags_lock); + return ret; + } + + rv8803->alarm_invalid = false; + } + + ret = rv8803_write_reg(rv8803->client, RV8803_FLAG, + flags & ~(RV8803_FLAG_V1F | RV8803_FLAG_V2F)); + + mutex_unlock(&rv8803->flags_lock); + + return ret; +} + +static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct rv8803_data *rv8803 = dev_get_drvdata(dev); + struct i2c_client *client = rv8803->client; + u8 alarmvals[3]; + int flags, ret; + + ret = rv8803_read_regs(client, RV8803_ALARM_MIN, 3, alarmvals); + if (ret) + return ret; + + flags = rv8803_read_reg(client, RV8803_FLAG); + if (flags < 0) + return flags; + + alarmvals[0] &= 0x7f; + alarmvals[1] &= 0x3f; + alarmvals[2] &= 0x3f; + + if (!bcd_is_valid(alarmvals[0]) || + !bcd_is_valid(alarmvals[1]) || + !bcd_is_valid(alarmvals[2])) + goto err_invalid; + + alrm->time.tm_sec = 0; + alrm->time.tm_min = bcd2bin(alarmvals[0]); + alrm->time.tm_hour = bcd2bin(alarmvals[1]); + alrm->time.tm_mday = bcd2bin(alarmvals[2]); + + alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE); + alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled; + + if ((unsigned int)alrm->time.tm_mday > 31 || + (unsigned int)alrm->time.tm_hour >= 24 || + (unsigned int)alrm->time.tm_min >= 60) + goto err_invalid; + + return 0; + +err_invalid: + rv8803->alarm_invalid = true; + return -EINVAL; +} + +static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct i2c_client *client = to_i2c_client(dev); + struct rv8803_data *rv8803 = dev_get_drvdata(dev); + u8 alarmvals[3]; + u8 ctrl[2]; + int ret, err; + + /* The alarm has no seconds, round up to nearest minute */ + if (alrm->time.tm_sec) { + time64_t alarm_time = rtc_tm_to_time64(&alrm->time); + + alarm_time += 60 - alrm->time.tm_sec; + rtc_time64_to_tm(alarm_time, &alrm->time); + } + + mutex_lock(&rv8803->flags_lock); + + ret = rv8803_read_regs(client, RV8803_FLAG, 2, ctrl); + if (ret) { + mutex_unlock(&rv8803->flags_lock); + return ret; + } + + alarmvals[0] = bin2bcd(alrm->time.tm_min); + alarmvals[1] = bin2bcd(alrm->time.tm_hour); + alarmvals[2] = bin2bcd(alrm->time.tm_mday); + + if (rv8803->ctrl & (RV8803_CTRL_AIE | RV8803_CTRL_UIE)) { + rv8803->ctrl &= ~(RV8803_CTRL_AIE | RV8803_CTRL_UIE); + err = rv8803_write_reg(rv8803->client, RV8803_CTRL, + rv8803->ctrl); + if (err) { + mutex_unlock(&rv8803->flags_lock); + return err; + } + } + + ctrl[0] &= ~RV8803_FLAG_AF; + err = rv8803_write_reg(rv8803->client, RV8803_FLAG, ctrl[0]); + mutex_unlock(&rv8803->flags_lock); + if (err) + return err; + + err = rv8803_write_regs(rv8803->client, RV8803_ALARM_MIN, 3, alarmvals); + if (err) + return err; + + if (alrm->enabled) { + if (rv8803->rtc->uie_rtctimer.enabled) + rv8803->ctrl |= RV8803_CTRL_UIE; + if (rv8803->rtc->aie_timer.enabled) + rv8803->ctrl |= RV8803_CTRL_AIE; + + err = rv8803_write_reg(rv8803->client, RV8803_CTRL, + rv8803->ctrl); + if (err) + return err; + } + + return 0; +} + +static int rv8803_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct i2c_client *client = to_i2c_client(dev); + struct rv8803_data *rv8803 = dev_get_drvdata(dev); + int ctrl, flags, err; + + ctrl = rv8803->ctrl; + + if (enabled) { + if (rv8803->rtc->uie_rtctimer.enabled) + ctrl |= RV8803_CTRL_UIE; + if (rv8803->rtc->aie_timer.enabled) + ctrl |= RV8803_CTRL_AIE; + } else { + if (!rv8803->rtc->uie_rtctimer.enabled) + ctrl &= ~RV8803_CTRL_UIE; + if (!rv8803->rtc->aie_timer.enabled) + ctrl &= ~RV8803_CTRL_AIE; + } + + mutex_lock(&rv8803->flags_lock); + flags = rv8803_read_reg(client, RV8803_FLAG); + if (flags < 0) { + mutex_unlock(&rv8803->flags_lock); + return flags; + } + flags &= ~(RV8803_FLAG_AF | RV8803_FLAG_UF); + err = rv8803_write_reg(client, RV8803_FLAG, flags); + mutex_unlock(&rv8803->flags_lock); + if (err) + return err; + + if (ctrl != rv8803->ctrl) { + rv8803->ctrl = ctrl; + err = rv8803_write_reg(client, RV8803_CTRL, rv8803->ctrl); + if (err) + return err; + } + + return 0; +} + +static int rv8803_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) +{ + struct i2c_client *client = to_i2c_client(dev); + struct rv8803_data *rv8803 = dev_get_drvdata(dev); + unsigned int vl = 0; + int flags, ret = 0; + + switch (cmd) { + case RTC_VL_READ: + flags = rv8803_read_reg(client, RV8803_FLAG); + if (flags < 0) + return flags; + + if (flags & RV8803_FLAG_V1F) { + dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); + vl = RTC_VL_ACCURACY_LOW; + } + + if (flags & RV8803_FLAG_V2F) + vl |= RTC_VL_DATA_INVALID; + + return put_user(vl, (unsigned int __user *)arg); + + case RTC_VL_CLR: + mutex_lock(&rv8803->flags_lock); + flags = rv8803_read_reg(client, RV8803_FLAG); + if (flags < 0) { + mutex_unlock(&rv8803->flags_lock); + return flags; + } + + flags &= ~RV8803_FLAG_V1F; + ret = rv8803_write_reg(client, RV8803_FLAG, flags); + mutex_unlock(&rv8803->flags_lock); + if (ret) + return ret; + + return 0; + + default: + return -ENOIOCTLCMD; + } +} + +static int rv8803_nvram_write(void *priv, unsigned int offset, void *val, + size_t bytes) +{ + return rv8803_write_reg(priv, RV8803_RAM, *(u8 *)val); +} + +static int rv8803_nvram_read(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + int ret; + + ret = rv8803_read_reg(priv, RV8803_RAM); + if (ret < 0) + return ret; + + *(u8 *)val = ret; + + return 0; +} + +static const struct rtc_class_ops rv8803_rtc_ops = { + .read_time = rv8803_get_time, + .set_time = rv8803_set_time, + .ioctl = rv8803_ioctl, + .read_alarm = rv8803_get_alarm, + .set_alarm = rv8803_set_alarm, + .alarm_irq_enable = rv8803_alarm_irq_enable, +}; + +static int rx8900_trickle_charger_init(struct rv8803_data *rv8803) +{ + struct i2c_client *client = rv8803->client; + struct device_node *node = client->dev.of_node; + int err; + u8 flags; + + if (!node) + return 0; + + if (rv8803->type != rx_8900) + return 0; + + err = i2c_smbus_read_byte_data(rv8803->client, RX8900_BACKUP_CTRL); + if (err < 0) + return err; + + flags = (u8)err; + flags &= ~(RX8900_FLAG_VDETOFF | RX8900_FLAG_SWOFF); + flags |= rv8803->backup; + + return i2c_smbus_write_byte_data(rv8803->client, RX8900_BACKUP_CTRL, + flags); +} + +/* configure registers with values different than the Power-On reset defaults */ +static int rv8803_regs_configure(struct rv8803_data *rv8803) +{ + int err; + + err = rv8803_write_reg(rv8803->client, RV8803_EXT, RV8803_EXT_WADA); + if (err) + return err; + + err = rx8900_trickle_charger_init(rv8803); + if (err) { + dev_err(&rv8803->client->dev, "failed to init charger\n"); + return err; + } + + return 0; +} + +static const struct i2c_device_id rv8803_id[] = { + { "rv8803", rv_8803 }, + { "rv8804", rx_8804 }, + { "rx8803", rx_8803 }, + { "rx8900", rx_8900 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, rv8803_id); + +static int rv8803_probe(struct i2c_client *client) +{ + struct i2c_adapter *adapter = client->adapter; + struct rv8803_data *rv8803; + int err, flags; + struct nvmem_config nvmem_cfg = { + .name = "rv8803_nvram", + .word_size = 1, + .stride = 1, + .size = 1, + .reg_read = rv8803_nvram_read, + .reg_write = rv8803_nvram_write, + .priv = client, + }; + + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_I2C_BLOCK)) { + dev_err(&adapter->dev, "doesn't support I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_I2C_BLOCK\n"); + return -EIO; + } + + rv8803 = devm_kzalloc(&client->dev, sizeof(struct rv8803_data), + GFP_KERNEL); + if (!rv8803) + return -ENOMEM; + + mutex_init(&rv8803->flags_lock); + rv8803->client = client; + if (client->dev.of_node) { + rv8803->type = (uintptr_t)of_device_get_match_data(&client->dev); + } else { + const struct i2c_device_id *id = i2c_match_id(rv8803_id, client); + + rv8803->type = id->driver_data; + } + i2c_set_clientdata(client, rv8803); + + flags = rv8803_read_reg(client, RV8803_FLAG); + if (flags < 0) + return flags; + + if (flags & RV8803_FLAG_V1F) + dev_warn(&client->dev, "Voltage low, temperature compensation stopped.\n"); + + if (flags & RV8803_FLAG_V2F) + dev_warn(&client->dev, "Voltage low, data loss detected.\n"); + + if (flags & RV8803_FLAG_AF) + dev_warn(&client->dev, "An alarm maybe have been missed.\n"); + + rv8803->rtc = devm_rtc_allocate_device(&client->dev); + if (IS_ERR(rv8803->rtc)) + return PTR_ERR(rv8803->rtc); + + if (client->irq > 0) { + unsigned long irqflags = IRQF_TRIGGER_LOW; + + if (dev_fwnode(&client->dev)) + irqflags = 0; + + err = devm_request_threaded_irq(&client->dev, client->irq, + NULL, rv8803_handle_irq, + irqflags | IRQF_ONESHOT, + "rv8803", client); + if (err) { + dev_warn(&client->dev, "unable to request IRQ, alarms disabled\n"); + client->irq = 0; + } + } + if (!client->irq) + clear_bit(RTC_FEATURE_ALARM, rv8803->rtc->features); + + if (of_property_read_bool(client->dev.of_node, "epson,vdet-disable")) + rv8803->backup |= RX8900_FLAG_VDETOFF; + + if (of_property_read_bool(client->dev.of_node, "trickle-diode-disable")) + rv8803->backup |= RX8900_FLAG_SWOFF; + + err = rv8803_regs_configure(rv8803); + if (err) + return err; + + rv8803->rtc->ops = &rv8803_rtc_ops; + rv8803->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000; + rv8803->rtc->range_max = RTC_TIMESTAMP_END_2099; + err = devm_rtc_register_device(rv8803->rtc); + if (err) + return err; + + devm_rtc_nvmem_register(rv8803->rtc, &nvmem_cfg); + + rv8803->rtc->max_user_freq = 1; + + return 0; +} + +static const __maybe_unused struct of_device_id rv8803_of_match[] = { + { + .compatible = "microcrystal,rv8803", + .data = (void *)rv_8803 + }, + { + .compatible = "epson,rx8803", + .data = (void *)rx_8803 + }, + { + .compatible = "epson,rx8804", + .data = (void *)rx_8804 + }, + { + .compatible = "epson,rx8900", + .data = (void *)rx_8900 + }, + { } +}; +MODULE_DEVICE_TABLE(of, rv8803_of_match); + +static struct i2c_driver rv8803_driver = { + .driver = { + .name = "rtc-rv8803", + .of_match_table = of_match_ptr(rv8803_of_match), + }, + .probe = rv8803_probe, + .id_table = rv8803_id, +}; +module_i2c_driver(rv8803_driver); + +MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>"); +MODULE_DESCRIPTION("Micro Crystal RV8803 RTC driver"); +MODULE_LICENSE("GPL v2"); |