/* * 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_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 regmap *regmap; struct mutex lock; }; 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] & 0x0f); 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]) - 1; /* starts at 1 */ tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100; } static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm) { /* * The clock has an 8 bit wide bcd-coded register for the year. * tm_year is an offset from 1900 and we are interested in the * 2000-2099 range, so any value less than 100 is invalid. */ if (tm->tm_year < 100) return -EINVAL; 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); 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_read_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; mutex_lock(&data->lock); ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs, ISL12057_RTC_SEC_LEN); mutex_unlock(&data->lock); if (ret) { dev_err(dev, "%s: RTC read failed\n", __func__); return ret; } isl12057_rtc_regs_to_tm(tm, regs); return rtc_valid_tm(tm); } 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); mutex_unlock(&data->lock); if (ret) dev_err(dev, "%s: RTC write failed\n", __func__); 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, "Unable to enable oscillator\n"); return ret; } /* Clear oscillator failure bit if needed */ ret = regmap_update_bits(regmap, ISL12057_REG_SR, ISL12057_REG_SR_OSF, 0); if (ret < 0) { dev_err(dev, "Unable to clear oscillator failure bit\n"); 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, "Unable to clear alarm bit\n"); return ret; } return 0; } static const struct rtc_class_ops rtc_ops = { .read_time = isl12057_rtc_read_time, .set_time = isl12057_rtc_set_time, }; static 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 rtc_device *rtc; 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, "regmap allocation failed: %d\n", 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); rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, THIS_MODULE); return PTR_ERR_OR_ZERO(rtc); } #ifdef CONFIG_OF static const struct of_device_id isl12057_dt_match[] = { { .compatible = "isl,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, .of_match_table = of_match_ptr(isl12057_dt_match), }, .probe = isl12057_probe, .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");