diff options
Diffstat (limited to 'drivers/rtc/rtc-isl12057.c')
-rw-r--r-- | drivers/rtc/rtc-isl12057.c | 674 |
1 files changed, 674 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-isl12057.c b/drivers/rtc/rtc-isl12057.c new file mode 100644 index 000000000..da818d333 --- /dev/null +++ b/drivers/rtc/rtc-isl12057.c @@ -0,0 +1,674 @@ +/* + * rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock + * + * Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org> + * + * This work is largely based on Intersil ISL1208 driver developed by + * Hebert Valerio Riedel <hvr@gnu.org>. + * + * Detailed datasheet on which this development is based is available here: + * + * http://natisbad.org/NAS2/refs/ISL12057.pdf + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/rtc.h> +#include <linux/i2c.h> +#include <linux/bcd.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/regmap.h> + +#define DRV_NAME "rtc-isl12057" + +/* RTC section */ +#define ISL12057_REG_RTC_SC 0x00 /* Seconds */ +#define ISL12057_REG_RTC_MN 0x01 /* Minutes */ +#define ISL12057_REG_RTC_HR 0x02 /* Hours */ +#define ISL12057_REG_RTC_HR_PM BIT(5) /* AM/PM bit in 12h format */ +#define ISL12057_REG_RTC_HR_MIL BIT(6) /* 24h/12h format */ +#define ISL12057_REG_RTC_DW 0x03 /* Day of the Week */ +#define ISL12057_REG_RTC_DT 0x04 /* Date */ +#define ISL12057_REG_RTC_MO 0x05 /* Month */ +#define ISL12057_REG_RTC_MO_CEN BIT(7) /* Century bit */ +#define ISL12057_REG_RTC_YR 0x06 /* Year */ +#define ISL12057_RTC_SEC_LEN 7 + +/* Alarm 1 section */ +#define ISL12057_REG_A1_SC 0x07 /* Alarm 1 Seconds */ +#define ISL12057_REG_A1_MN 0x08 /* Alarm 1 Minutes */ +#define ISL12057_REG_A1_HR 0x09 /* Alarm 1 Hours */ +#define ISL12057_REG_A1_HR_PM BIT(5) /* AM/PM bit in 12h format */ +#define ISL12057_REG_A1_HR_MIL BIT(6) /* 24h/12h format */ +#define ISL12057_REG_A1_DWDT 0x0A /* Alarm 1 Date / Day of the week */ +#define ISL12057_REG_A1_DWDT_B BIT(6) /* DW / DT selection bit */ +#define ISL12057_A1_SEC_LEN 4 + +/* Alarm 2 section */ +#define ISL12057_REG_A2_MN 0x0B /* Alarm 2 Minutes */ +#define ISL12057_REG_A2_HR 0x0C /* Alarm 2 Hours */ +#define ISL12057_REG_A2_DWDT 0x0D /* Alarm 2 Date / Day of the week */ +#define ISL12057_A2_SEC_LEN 3 + +/* Control/Status registers */ +#define ISL12057_REG_INT 0x0E +#define ISL12057_REG_INT_A1IE BIT(0) /* Alarm 1 interrupt enable bit */ +#define ISL12057_REG_INT_A2IE BIT(1) /* Alarm 2 interrupt enable bit */ +#define ISL12057_REG_INT_INTCN BIT(2) /* Interrupt control enable bit */ +#define ISL12057_REG_INT_RS1 BIT(3) /* Freq out control bit 1 */ +#define ISL12057_REG_INT_RS2 BIT(4) /* Freq out control bit 2 */ +#define ISL12057_REG_INT_EOSC BIT(7) /* Oscillator enable bit */ + +#define ISL12057_REG_SR 0x0F +#define ISL12057_REG_SR_A1F BIT(0) /* Alarm 1 interrupt bit */ +#define ISL12057_REG_SR_A2F BIT(1) /* Alarm 2 interrupt bit */ +#define ISL12057_REG_SR_OSF BIT(7) /* Oscillator failure bit */ + +/* Register memory map length */ +#define ISL12057_MEM_MAP_LEN 0x10 + +struct isl12057_rtc_data { + struct rtc_device *rtc; + struct regmap *regmap; + struct mutex lock; + int irq; +}; + +static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs) +{ + tm->tm_sec = bcd2bin(regs[ISL12057_REG_RTC_SC]); + tm->tm_min = bcd2bin(regs[ISL12057_REG_RTC_MN]); + + if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_MIL) { /* AM/PM */ + tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x1f); + if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_PM) + tm->tm_hour += 12; + } else { /* 24 hour mode */ + tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x3f); + } + + tm->tm_mday = bcd2bin(regs[ISL12057_REG_RTC_DT]); + tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */ + tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO] & 0x1f) - 1; /* ditto */ + tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100; + + /* Check if years register has overflown from 99 to 00 */ + if (regs[ISL12057_REG_RTC_MO] & ISL12057_REG_RTC_MO_CEN) + tm->tm_year += 100; +} + +static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm) +{ + u8 century_bit; + + /* + * The clock has an 8 bit wide bcd-coded register for the year. + * It also has a century bit encoded in MO flag which provides + * information about overflow of year register from 99 to 00. + * tm_year is an offset from 1900 and we are interested in the + * 2000-2199 range, so any value less than 100 or larger than + * 299 is invalid. + */ + if (tm->tm_year < 100 || tm->tm_year > 299) + return -EINVAL; + + century_bit = (tm->tm_year > 199) ? ISL12057_REG_RTC_MO_CEN : 0; + + regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec); + regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min); + regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */ + regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday); + regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1) | century_bit; + regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year % 100); + regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1); + + return 0; +} + +/* + * Try and match register bits w/ fixed null values to see whether we + * are dealing with an ISL12057. Note: this function is called early + * during init and hence does need mutex protection. + */ +static int isl12057_i2c_validate_chip(struct regmap *regmap) +{ + u8 regs[ISL12057_MEM_MAP_LEN]; + static const u8 mask[ISL12057_MEM_MAP_LEN] = { 0x80, 0x80, 0x80, 0xf8, + 0xc0, 0x60, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x60, 0x7c }; + int ret, i; + + ret = regmap_bulk_read(regmap, 0, regs, ISL12057_MEM_MAP_LEN); + if (ret) + return ret; + + for (i = 0; i < ISL12057_MEM_MAP_LEN; ++i) { + if (regs[i] & mask[i]) /* check if bits are cleared */ + return -ENODEV; + } + + return 0; +} + +static int _isl12057_rtc_clear_alarm(struct device *dev) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + int ret; + + ret = regmap_update_bits(data->regmap, ISL12057_REG_SR, + ISL12057_REG_SR_A1F, 0); + if (ret) + dev_err(dev, "%s: clearing alarm failed (%d)\n", __func__, ret); + + return ret; +} + +static int _isl12057_rtc_update_alarm(struct device *dev, int enable) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + int ret; + + ret = regmap_update_bits(data->regmap, ISL12057_REG_INT, + ISL12057_REG_INT_A1IE, + enable ? ISL12057_REG_INT_A1IE : 0); + if (ret) + dev_err(dev, "%s: changing alarm interrupt flag failed (%d)\n", + __func__, ret); + + return ret; +} + +/* + * Note: as we only read from device and do not perform any update, there is + * no need for an equivalent function which would try and get driver's main + * lock. Here, it is safe for everyone if we just use regmap internal lock + * on the device when reading. + */ +static int _isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + u8 regs[ISL12057_RTC_SEC_LEN]; + unsigned int sr; + int ret; + + ret = regmap_read(data->regmap, ISL12057_REG_SR, &sr); + if (ret) { + dev_err(dev, "%s: unable to read oscillator status flag (%d)\n", + __func__, ret); + goto out; + } else { + if (sr & ISL12057_REG_SR_OSF) { + ret = -ENODATA; + goto out; + } + } + + ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs, + ISL12057_RTC_SEC_LEN); + if (ret) + dev_err(dev, "%s: unable to read RTC time section (%d)\n", + __func__, ret); + +out: + if (ret) + return ret; + + isl12057_rtc_regs_to_tm(tm, regs); + + return rtc_valid_tm(tm); +} + +static int isl12057_rtc_update_alarm(struct device *dev, int enable) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + int ret; + + mutex_lock(&data->lock); + ret = _isl12057_rtc_update_alarm(dev, enable); + mutex_unlock(&data->lock); + + return ret; +} + +static int isl12057_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + struct rtc_time rtc_tm, *alarm_tm = &alarm->time; + unsigned long rtc_secs, alarm_secs; + u8 regs[ISL12057_A1_SEC_LEN]; + unsigned int ir; + int ret; + + mutex_lock(&data->lock); + ret = regmap_bulk_read(data->regmap, ISL12057_REG_A1_SC, regs, + ISL12057_A1_SEC_LEN); + if (ret) { + dev_err(dev, "%s: reading alarm section failed (%d)\n", + __func__, ret); + goto err_unlock; + } + + alarm_tm->tm_sec = bcd2bin(regs[0] & 0x7f); + alarm_tm->tm_min = bcd2bin(regs[1] & 0x7f); + alarm_tm->tm_hour = bcd2bin(regs[2] & 0x3f); + alarm_tm->tm_mday = bcd2bin(regs[3] & 0x3f); + alarm_tm->tm_wday = -1; + + /* + * The alarm section does not store year/month. We use the ones in rtc + * section as a basis and increment month and then year if needed to get + * alarm after current time. + */ + ret = _isl12057_rtc_read_time(dev, &rtc_tm); + if (ret) + goto err_unlock; + + alarm_tm->tm_year = rtc_tm.tm_year; + alarm_tm->tm_mon = rtc_tm.tm_mon; + + ret = rtc_tm_to_time(&rtc_tm, &rtc_secs); + if (ret) + goto err_unlock; + + ret = rtc_tm_to_time(alarm_tm, &alarm_secs); + if (ret) + goto err_unlock; + + if (alarm_secs < rtc_secs) { + if (alarm_tm->tm_mon == 11) { + alarm_tm->tm_mon = 0; + alarm_tm->tm_year += 1; + } else { + alarm_tm->tm_mon += 1; + } + } + + ret = regmap_read(data->regmap, ISL12057_REG_INT, &ir); + if (ret) { + dev_err(dev, "%s: reading alarm interrupt flag failed (%d)\n", + __func__, ret); + goto err_unlock; + } + + alarm->enabled = !!(ir & ISL12057_REG_INT_A1IE); + +err_unlock: + mutex_unlock(&data->lock); + + return ret; +} + +static int isl12057_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + struct rtc_time *alarm_tm = &alarm->time; + unsigned long rtc_secs, alarm_secs; + u8 regs[ISL12057_A1_SEC_LEN]; + struct rtc_time rtc_tm; + int ret, enable = 1; + + mutex_lock(&data->lock); + ret = _isl12057_rtc_read_time(dev, &rtc_tm); + if (ret) + goto err_unlock; + + ret = rtc_tm_to_time(&rtc_tm, &rtc_secs); + if (ret) + goto err_unlock; + + ret = rtc_tm_to_time(alarm_tm, &alarm_secs); + if (ret) + goto err_unlock; + + /* If alarm time is before current time, disable the alarm */ + if (!alarm->enabled || alarm_secs <= rtc_secs) { + enable = 0; + } else { + /* + * Chip only support alarms up to one month in the future. Let's + * return an error if we get something after that limit. + * Comparison is done by incrementing rtc_tm month field by one + * and checking alarm value is still below. + */ + if (rtc_tm.tm_mon == 11) { /* handle year wrapping */ + rtc_tm.tm_mon = 0; + rtc_tm.tm_year += 1; + } else { + rtc_tm.tm_mon += 1; + } + + ret = rtc_tm_to_time(&rtc_tm, &rtc_secs); + if (ret) + goto err_unlock; + + if (alarm_secs > rtc_secs) { + dev_err(dev, "%s: max for alarm is one month (%d)\n", + __func__, ret); + ret = -EINVAL; + goto err_unlock; + } + } + + /* Disable the alarm before modifying it */ + ret = _isl12057_rtc_update_alarm(dev, 0); + if (ret < 0) { + dev_err(dev, "%s: unable to disable the alarm (%d)\n", + __func__, ret); + goto err_unlock; + } + + /* Program alarm registers */ + regs[0] = bin2bcd(alarm_tm->tm_sec) & 0x7f; + regs[1] = bin2bcd(alarm_tm->tm_min) & 0x7f; + regs[2] = bin2bcd(alarm_tm->tm_hour) & 0x3f; + regs[3] = bin2bcd(alarm_tm->tm_mday) & 0x3f; + + ret = regmap_bulk_write(data->regmap, ISL12057_REG_A1_SC, regs, + ISL12057_A1_SEC_LEN); + if (ret < 0) { + dev_err(dev, "%s: writing alarm section failed (%d)\n", + __func__, ret); + goto err_unlock; + } + + /* Enable or disable alarm */ + ret = _isl12057_rtc_update_alarm(dev, enable); + +err_unlock: + mutex_unlock(&data->lock); + + return ret; +} + +static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + u8 regs[ISL12057_RTC_SEC_LEN]; + int ret; + + ret = isl12057_rtc_tm_to_regs(regs, tm); + if (ret) + return ret; + + mutex_lock(&data->lock); + ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs, + ISL12057_RTC_SEC_LEN); + if (ret) { + dev_err(dev, "%s: unable to write RTC time section (%d)\n", + __func__, ret); + goto out; + } + + /* + * Now that RTC time has been updated, let's clear oscillator + * failure flag, if needed. + */ + ret = regmap_update_bits(data->regmap, ISL12057_REG_SR, + ISL12057_REG_SR_OSF, 0); + if (ret < 0) + dev_err(dev, "%s: unable to clear osc. failure bit (%d)\n", + __func__, ret); + +out: + mutex_unlock(&data->lock); + + return ret; +} + +/* + * Check current RTC status and enable/disable what needs to be. Return 0 if + * everything went ok and a negative value upon error. Note: this function + * is called early during init and hence does need mutex protection. + */ +static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap) +{ + int ret; + + /* Enable oscillator if not already running */ + ret = regmap_update_bits(regmap, ISL12057_REG_INT, + ISL12057_REG_INT_EOSC, 0); + if (ret < 0) { + dev_err(dev, "%s: unable to enable oscillator (%d)\n", + __func__, ret); + return ret; + } + + /* Clear alarm bit if needed */ + ret = regmap_update_bits(regmap, ISL12057_REG_SR, + ISL12057_REG_SR_A1F, 0); + if (ret < 0) { + dev_err(dev, "%s: unable to clear alarm bit (%d)\n", + __func__, ret); + return ret; + } + + return 0; +} + +#ifdef CONFIG_OF +/* + * One would expect the device to be marked as a wakeup source only + * when an IRQ pin of the RTC is routed to an interrupt line of the + * CPU. In practice, such an IRQ pin can be connected to a PMIC and + * this allows the device to be powered up when RTC alarm rings. This + * is for instance the case on ReadyNAS 102, 104 and 2120. On those + * devices with no IRQ driectly connected to the SoC, the RTC chip + * can be forced as a wakeup source by stating that explicitly in + * the device's .dts file using the "isil,irq2-can-wakeup-machine" + * boolean property. This will guarantee 'wakealarm' sysfs entry is + * available on the device. + * + * The function below returns 1, i.e. the capability of the chip to + * wakeup the device, based on IRQ availability or if the boolean + * property has been set in the .dts file. Otherwise, it returns 0. + */ + +static bool isl12057_can_wakeup_machine(struct device *dev) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + + return (data->irq || of_property_read_bool(dev->of_node, + "isil,irq2-can-wakeup-machine")); +} +#else +static bool isl12057_can_wakeup_machine(struct device *dev) +{ + struct isl12057_rtc_data *data = dev_get_drvdata(dev); + + return !!data->irq; +} +#endif + +static int isl12057_rtc_alarm_irq_enable(struct device *dev, + unsigned int enable) +{ + struct isl12057_rtc_data *rtc_data = dev_get_drvdata(dev); + int ret = -ENOTTY; + + if (rtc_data->irq) + ret = isl12057_rtc_update_alarm(dev, enable); + + return ret; +} + +static irqreturn_t isl12057_rtc_interrupt(int irq, void *data) +{ + struct i2c_client *client = data; + struct isl12057_rtc_data *rtc_data = dev_get_drvdata(&client->dev); + struct rtc_device *rtc = rtc_data->rtc; + int ret, handled = IRQ_NONE; + unsigned int sr; + + ret = regmap_read(rtc_data->regmap, ISL12057_REG_SR, &sr); + if (!ret && (sr & ISL12057_REG_SR_A1F)) { + dev_dbg(&client->dev, "RTC alarm!\n"); + + rtc_update_irq(rtc, 1, RTC_IRQF | RTC_AF); + + /* Acknowledge and disable the alarm */ + _isl12057_rtc_clear_alarm(&client->dev); + _isl12057_rtc_update_alarm(&client->dev, 0); + + handled = IRQ_HANDLED; + } + + return handled; +} + +static const struct rtc_class_ops rtc_ops = { + .read_time = _isl12057_rtc_read_time, + .set_time = isl12057_rtc_set_time, + .read_alarm = isl12057_rtc_read_alarm, + .set_alarm = isl12057_rtc_set_alarm, + .alarm_irq_enable = isl12057_rtc_alarm_irq_enable, +}; + +static const struct regmap_config isl12057_rtc_regmap_config = { + .reg_bits = 8, + .val_bits = 8, +}; + +static int isl12057_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct device *dev = &client->dev; + struct isl12057_rtc_data *data; + struct regmap *regmap; + int ret; + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | + I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_I2C_BLOCK)) + return -ENODEV; + + regmap = devm_regmap_init_i2c(client, &isl12057_rtc_regmap_config); + if (IS_ERR(regmap)) { + ret = PTR_ERR(regmap); + dev_err(dev, "%s: regmap allocation failed (%d)\n", + __func__, ret); + return ret; + } + + ret = isl12057_i2c_validate_chip(regmap); + if (ret) + return ret; + + ret = isl12057_check_rtc_status(dev, regmap); + if (ret) + return ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + mutex_init(&data->lock); + data->regmap = regmap; + dev_set_drvdata(dev, data); + + if (client->irq > 0) { + ret = devm_request_threaded_irq(dev, client->irq, NULL, + isl12057_rtc_interrupt, + IRQF_SHARED|IRQF_ONESHOT, + DRV_NAME, client); + if (!ret) + data->irq = client->irq; + else + dev_err(dev, "%s: irq %d unavailable (%d)\n", __func__, + client->irq, ret); + } + + if (isl12057_can_wakeup_machine(dev)) + device_init_wakeup(dev, true); + + data->rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, + THIS_MODULE); + ret = PTR_ERR_OR_ZERO(data->rtc); + if (ret) { + dev_err(dev, "%s: unable to register RTC device (%d)\n", + __func__, ret); + goto err; + } + + /* We cannot support UIE mode if we do not have an IRQ line */ + if (!data->irq) + data->rtc->uie_unsupported = 1; + +err: + return ret; +} + +static int isl12057_remove(struct i2c_client *client) +{ + if (isl12057_can_wakeup_machine(&client->dev)) + device_init_wakeup(&client->dev, false); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int isl12057_rtc_suspend(struct device *dev) +{ + struct isl12057_rtc_data *rtc_data = dev_get_drvdata(dev); + + if (rtc_data->irq && device_may_wakeup(dev)) + return enable_irq_wake(rtc_data->irq); + + return 0; +} + +static int isl12057_rtc_resume(struct device *dev) +{ + struct isl12057_rtc_data *rtc_data = dev_get_drvdata(dev); + + if (rtc_data->irq && device_may_wakeup(dev)) + return disable_irq_wake(rtc_data->irq); + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(isl12057_rtc_pm_ops, isl12057_rtc_suspend, + isl12057_rtc_resume); + +#ifdef CONFIG_OF +static const struct of_device_id isl12057_dt_match[] = { + { .compatible = "isl,isl12057" }, /* for backward compat., don't use */ + { .compatible = "isil,isl12057" }, + { }, +}; +#endif + +static const struct i2c_device_id isl12057_id[] = { + { "isl12057", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, isl12057_id); + +static struct i2c_driver isl12057_driver = { + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + .pm = &isl12057_rtc_pm_ops, + .of_match_table = of_match_ptr(isl12057_dt_match), + }, + .probe = isl12057_probe, + .remove = isl12057_remove, + .id_table = isl12057_id, +}; +module_i2c_driver(isl12057_driver); + +MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>"); +MODULE_DESCRIPTION("Intersil ISL12057 RTC driver"); +MODULE_LICENSE("GPL"); |