| /* |
| * 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 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] & 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_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"); |