1/* 2 * rtc-isl12057 - Driver for Intersil ISL12057 I2C Real Time Clock 3 * 4 * Copyright (C) 2013, Arnaud EBALARD <arno@natisbad.org> 5 * 6 * This work is largely based on Intersil ISL1208 driver developed by 7 * Hebert Valerio Riedel <hvr@gnu.org>. 8 * 9 * Detailed datasheet on which this development is based is available here: 10 * 11 * http://natisbad.org/NAS2/refs/ISL12057.pdf 12 * 13 * This program is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU General Public License as published by 15 * the Free Software Foundation; either version 2 of the License, or 16 * (at your option) any later version. 17 * 18 * This program is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21 * GNU General Public License for more details. 22 */ 23 24#include <linux/module.h> 25#include <linux/mutex.h> 26#include <linux/rtc.h> 27#include <linux/i2c.h> 28#include <linux/bcd.h> 29#include <linux/of.h> 30#include <linux/of_device.h> 31#include <linux/regmap.h> 32 33#define DRV_NAME "rtc-isl12057" 34 35/* RTC section */ 36#define ISL12057_REG_RTC_SC 0x00 /* Seconds */ 37#define ISL12057_REG_RTC_MN 0x01 /* Minutes */ 38#define ISL12057_REG_RTC_HR 0x02 /* Hours */ 39#define ISL12057_REG_RTC_HR_PM BIT(5) /* AM/PM bit in 12h format */ 40#define ISL12057_REG_RTC_HR_MIL BIT(6) /* 24h/12h format */ 41#define ISL12057_REG_RTC_DW 0x03 /* Day of the Week */ 42#define ISL12057_REG_RTC_DT 0x04 /* Date */ 43#define ISL12057_REG_RTC_MO 0x05 /* Month */ 44#define ISL12057_REG_RTC_YR 0x06 /* Year */ 45#define ISL12057_RTC_SEC_LEN 7 46 47/* Alarm 1 section */ 48#define ISL12057_REG_A1_SC 0x07 /* Alarm 1 Seconds */ 49#define ISL12057_REG_A1_MN 0x08 /* Alarm 1 Minutes */ 50#define ISL12057_REG_A1_HR 0x09 /* Alarm 1 Hours */ 51#define ISL12057_REG_A1_HR_PM BIT(5) /* AM/PM bit in 12h format */ 52#define ISL12057_REG_A1_HR_MIL BIT(6) /* 24h/12h format */ 53#define ISL12057_REG_A1_DWDT 0x0A /* Alarm 1 Date / Day of the week */ 54#define ISL12057_REG_A1_DWDT_B BIT(6) /* DW / DT selection bit */ 55#define ISL12057_A1_SEC_LEN 4 56 57/* Alarm 2 section */ 58#define ISL12057_REG_A2_MN 0x0B /* Alarm 2 Minutes */ 59#define ISL12057_REG_A2_HR 0x0C /* Alarm 2 Hours */ 60#define ISL12057_REG_A2_DWDT 0x0D /* Alarm 2 Date / Day of the week */ 61#define ISL12057_A2_SEC_LEN 3 62 63/* Control/Status registers */ 64#define ISL12057_REG_INT 0x0E 65#define ISL12057_REG_INT_A1IE BIT(0) /* Alarm 1 interrupt enable bit */ 66#define ISL12057_REG_INT_A2IE BIT(1) /* Alarm 2 interrupt enable bit */ 67#define ISL12057_REG_INT_INTCN BIT(2) /* Interrupt control enable bit */ 68#define ISL12057_REG_INT_RS1 BIT(3) /* Freq out control bit 1 */ 69#define ISL12057_REG_INT_RS2 BIT(4) /* Freq out control bit 2 */ 70#define ISL12057_REG_INT_EOSC BIT(7) /* Oscillator enable bit */ 71 72#define ISL12057_REG_SR 0x0F 73#define ISL12057_REG_SR_A1F BIT(0) /* Alarm 1 interrupt bit */ 74#define ISL12057_REG_SR_A2F BIT(1) /* Alarm 2 interrupt bit */ 75#define ISL12057_REG_SR_OSF BIT(7) /* Oscillator failure bit */ 76 77/* Register memory map length */ 78#define ISL12057_MEM_MAP_LEN 0x10 79 80struct isl12057_rtc_data { 81 struct regmap *regmap; 82 struct mutex lock; 83}; 84 85static void isl12057_rtc_regs_to_tm(struct rtc_time *tm, u8 *regs) 86{ 87 tm->tm_sec = bcd2bin(regs[ISL12057_REG_RTC_SC]); 88 tm->tm_min = bcd2bin(regs[ISL12057_REG_RTC_MN]); 89 90 if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_MIL) { /* AM/PM */ 91 tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x0f); 92 if (regs[ISL12057_REG_RTC_HR] & ISL12057_REG_RTC_HR_PM) 93 tm->tm_hour += 12; 94 } else { /* 24 hour mode */ 95 tm->tm_hour = bcd2bin(regs[ISL12057_REG_RTC_HR] & 0x3f); 96 } 97 98 tm->tm_mday = bcd2bin(regs[ISL12057_REG_RTC_DT]); 99 tm->tm_wday = bcd2bin(regs[ISL12057_REG_RTC_DW]) - 1; /* starts at 1 */ 100 tm->tm_mon = bcd2bin(regs[ISL12057_REG_RTC_MO]) - 1; /* starts at 1 */ 101 tm->tm_year = bcd2bin(regs[ISL12057_REG_RTC_YR]) + 100; 102} 103 104static int isl12057_rtc_tm_to_regs(u8 *regs, struct rtc_time *tm) 105{ 106 /* 107 * The clock has an 8 bit wide bcd-coded register for the year. 108 * tm_year is an offset from 1900 and we are interested in the 109 * 2000-2099 range, so any value less than 100 is invalid. 110 */ 111 if (tm->tm_year < 100) 112 return -EINVAL; 113 114 regs[ISL12057_REG_RTC_SC] = bin2bcd(tm->tm_sec); 115 regs[ISL12057_REG_RTC_MN] = bin2bcd(tm->tm_min); 116 regs[ISL12057_REG_RTC_HR] = bin2bcd(tm->tm_hour); /* 24-hour format */ 117 regs[ISL12057_REG_RTC_DT] = bin2bcd(tm->tm_mday); 118 regs[ISL12057_REG_RTC_MO] = bin2bcd(tm->tm_mon + 1); 119 regs[ISL12057_REG_RTC_YR] = bin2bcd(tm->tm_year - 100); 120 regs[ISL12057_REG_RTC_DW] = bin2bcd(tm->tm_wday + 1); 121 122 return 0; 123} 124 125/* 126 * Try and match register bits w/ fixed null values to see whether we 127 * are dealing with an ISL12057. Note: this function is called early 128 * during init and hence does need mutex protection. 129 */ 130static int isl12057_i2c_validate_chip(struct regmap *regmap) 131{ 132 u8 regs[ISL12057_MEM_MAP_LEN]; 133 static const u8 mask[ISL12057_MEM_MAP_LEN] = { 0x80, 0x80, 0x80, 0xf8, 134 0xc0, 0x60, 0x00, 0x00, 135 0x00, 0x00, 0x00, 0x00, 136 0x00, 0x00, 0x60, 0x7c }; 137 int ret, i; 138 139 ret = regmap_bulk_read(regmap, 0, regs, ISL12057_MEM_MAP_LEN); 140 if (ret) 141 return ret; 142 143 for (i = 0; i < ISL12057_MEM_MAP_LEN; ++i) { 144 if (regs[i] & mask[i]) /* check if bits are cleared */ 145 return -ENODEV; 146 } 147 148 return 0; 149} 150 151static int isl12057_rtc_read_time(struct device *dev, struct rtc_time *tm) 152{ 153 struct isl12057_rtc_data *data = dev_get_drvdata(dev); 154 u8 regs[ISL12057_RTC_SEC_LEN]; 155 int ret; 156 157 mutex_lock(&data->lock); 158 ret = regmap_bulk_read(data->regmap, ISL12057_REG_RTC_SC, regs, 159 ISL12057_RTC_SEC_LEN); 160 mutex_unlock(&data->lock); 161 162 if (ret) { 163 dev_err(dev, "%s: RTC read failed\n", __func__); 164 return ret; 165 } 166 167 isl12057_rtc_regs_to_tm(tm, regs); 168 169 return rtc_valid_tm(tm); 170} 171 172static int isl12057_rtc_set_time(struct device *dev, struct rtc_time *tm) 173{ 174 struct isl12057_rtc_data *data = dev_get_drvdata(dev); 175 u8 regs[ISL12057_RTC_SEC_LEN]; 176 int ret; 177 178 ret = isl12057_rtc_tm_to_regs(regs, tm); 179 if (ret) 180 return ret; 181 182 mutex_lock(&data->lock); 183 ret = regmap_bulk_write(data->regmap, ISL12057_REG_RTC_SC, regs, 184 ISL12057_RTC_SEC_LEN); 185 mutex_unlock(&data->lock); 186 187 if (ret) 188 dev_err(dev, "%s: RTC write failed\n", __func__); 189 190 return ret; 191} 192 193/* 194 * Check current RTC status and enable/disable what needs to be. Return 0 if 195 * everything went ok and a negative value upon error. Note: this function 196 * is called early during init and hence does need mutex protection. 197 */ 198static int isl12057_check_rtc_status(struct device *dev, struct regmap *regmap) 199{ 200 int ret; 201 202 /* Enable oscillator if not already running */ 203 ret = regmap_update_bits(regmap, ISL12057_REG_INT, 204 ISL12057_REG_INT_EOSC, 0); 205 if (ret < 0) { 206 dev_err(dev, "Unable to enable oscillator\n"); 207 return ret; 208 } 209 210 /* Clear oscillator failure bit if needed */ 211 ret = regmap_update_bits(regmap, ISL12057_REG_SR, 212 ISL12057_REG_SR_OSF, 0); 213 if (ret < 0) { 214 dev_err(dev, "Unable to clear oscillator failure bit\n"); 215 return ret; 216 } 217 218 /* Clear alarm bit if needed */ 219 ret = regmap_update_bits(regmap, ISL12057_REG_SR, 220 ISL12057_REG_SR_A1F, 0); 221 if (ret < 0) { 222 dev_err(dev, "Unable to clear alarm bit\n"); 223 return ret; 224 } 225 226 return 0; 227} 228 229static const struct rtc_class_ops rtc_ops = { 230 .read_time = isl12057_rtc_read_time, 231 .set_time = isl12057_rtc_set_time, 232}; 233 234static struct regmap_config isl12057_rtc_regmap_config = { 235 .reg_bits = 8, 236 .val_bits = 8, 237}; 238 239static int isl12057_probe(struct i2c_client *client, 240 const struct i2c_device_id *id) 241{ 242 struct device *dev = &client->dev; 243 struct isl12057_rtc_data *data; 244 struct rtc_device *rtc; 245 struct regmap *regmap; 246 int ret; 247 248 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C | 249 I2C_FUNC_SMBUS_BYTE_DATA | 250 I2C_FUNC_SMBUS_I2C_BLOCK)) 251 return -ENODEV; 252 253 regmap = devm_regmap_init_i2c(client, &isl12057_rtc_regmap_config); 254 if (IS_ERR(regmap)) { 255 ret = PTR_ERR(regmap); 256 dev_err(dev, "regmap allocation failed: %d\n", ret); 257 return ret; 258 } 259 260 ret = isl12057_i2c_validate_chip(regmap); 261 if (ret) 262 return ret; 263 264 ret = isl12057_check_rtc_status(dev, regmap); 265 if (ret) 266 return ret; 267 268 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 269 if (!data) 270 return -ENOMEM; 271 272 mutex_init(&data->lock); 273 data->regmap = regmap; 274 dev_set_drvdata(dev, data); 275 276 rtc = devm_rtc_device_register(dev, DRV_NAME, &rtc_ops, THIS_MODULE); 277 return PTR_ERR_OR_ZERO(rtc); 278} 279 280#ifdef CONFIG_OF 281static const struct of_device_id isl12057_dt_match[] = { 282 { .compatible = "isl,isl12057" }, 283 { }, 284}; 285#endif 286 287static const struct i2c_device_id isl12057_id[] = { 288 { "isl12057", 0 }, 289 { } 290}; 291MODULE_DEVICE_TABLE(i2c, isl12057_id); 292 293static struct i2c_driver isl12057_driver = { 294 .driver = { 295 .name = DRV_NAME, 296 .owner = THIS_MODULE, 297 .of_match_table = of_match_ptr(isl12057_dt_match), 298 }, 299 .probe = isl12057_probe, 300 .id_table = isl12057_id, 301}; 302module_i2c_driver(isl12057_driver); 303 304MODULE_AUTHOR("Arnaud EBALARD <arno@natisbad.org>"); 305MODULE_DESCRIPTION("Intersil ISL12057 RTC driver"); 306MODULE_LICENSE("GPL"); 307