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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * An I2C driver for the Epson RX8581 RTC4 *5 * Author: Martyn Welch <martyn.welch@ge.com>6 * Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.7 *8 * Based on: rtc-pcf8563.c (An I2C driver for the Philips PCF8563 RTC)9 * Copyright 2005-06 Tower Technologies10 */11 12#include <linux/module.h>13#include <linux/i2c.h>14#include <linux/bcd.h>15#include <linux/of.h>16#include <linux/regmap.h>17#include <linux/rtc.h>18#include <linux/log2.h>19 20#define RX8581_REG_SC 0x00 /* Second in BCD */21#define RX8581_REG_MN 0x01 /* Minute in BCD */22#define RX8581_REG_HR 0x02 /* Hour in BCD */23#define RX8581_REG_DW 0x03 /* Day of Week */24#define RX8581_REG_DM 0x04 /* Day of Month in BCD */25#define RX8581_REG_MO 0x05 /* Month in BCD */26#define RX8581_REG_YR 0x06 /* Year in BCD */27#define RX8581_REG_RAM 0x07 /* RAM */28#define RX8581_REG_AMN 0x08 /* Alarm Min in BCD*/29#define RX8581_REG_AHR 0x09 /* Alarm Hour in BCD */30#define RX8581_REG_ADM 0x0A31#define RX8581_REG_ADW 0x0A32#define RX8581_REG_TMR0 0x0B33#define RX8581_REG_TMR1 0x0C34#define RX8581_REG_EXT 0x0D /* Extension Register */35#define RX8581_REG_FLAG 0x0E /* Flag Register */36#define RX8581_REG_CTRL 0x0F /* Control Register */37 38 39/* Flag Register bit definitions */40#define RX8581_FLAG_UF 0x20 /* Update */41#define RX8581_FLAG_TF 0x10 /* Timer */42#define RX8581_FLAG_AF 0x08 /* Alarm */43#define RX8581_FLAG_VLF 0x02 /* Voltage Low */44 45/* Control Register bit definitions */46#define RX8581_CTRL_UIE 0x20 /* Update Interrupt Enable */47#define RX8581_CTRL_TIE 0x10 /* Timer Interrupt Enable */48#define RX8581_CTRL_AIE 0x08 /* Alarm Interrupt Enable */49#define RX8581_CTRL_STOP 0x02 /* STOP bit */50#define RX8581_CTRL_RESET 0x01 /* RESET bit */51 52#define RX8571_USER_RAM 0x1053#define RX8571_NVRAM_SIZE 0x1054 55struct rx8581 {56 struct regmap *regmap;57 struct rtc_device *rtc;58};59 60struct rx85x1_config {61 struct regmap_config regmap;62 unsigned int num_nvram;63};64 65/*66 * In the routines that deal directly with the rx8581 hardware, we use67 * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch.68 */69static int rx8581_rtc_read_time(struct device *dev, struct rtc_time *tm)70{71 struct i2c_client *client = to_i2c_client(dev);72 unsigned char date[7];73 unsigned int data;74 int err;75 struct rx8581 *rx8581 = i2c_get_clientdata(client);76 77 /* First we ensure that the "update flag" is not set, we read the78 * time and date then re-read the "update flag". If the update flag79 * has been set, we know that the time has changed during the read so80 * we repeat the whole process again.81 */82 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);83 if (err < 0)84 return err;85 86 if (data & RX8581_FLAG_VLF) {87 dev_warn(dev,88 "low voltage detected, date/time is not reliable.\n");89 return -EINVAL;90 }91 92 do {93 /* If update flag set, clear it */94 if (data & RX8581_FLAG_UF) {95 err = regmap_write(rx8581->regmap, RX8581_REG_FLAG,96 data & ~RX8581_FLAG_UF);97 if (err < 0)98 return err;99 }100 101 /* Now read time and date */102 err = regmap_bulk_read(rx8581->regmap, RX8581_REG_SC, date,103 sizeof(date));104 if (err < 0)105 return err;106 107 /* Check flag register */108 err = regmap_read(rx8581->regmap, RX8581_REG_FLAG, &data);109 if (err < 0)110 return err;111 } while (data & RX8581_FLAG_UF);112 113 dev_dbg(dev, "%s: raw data is sec=%02x, min=%02x, hr=%02x, "114 "wday=%02x, mday=%02x, mon=%02x, year=%02x\n",115 __func__,116 date[0], date[1], date[2], date[3], date[4], date[5], date[6]);117 118 tm->tm_sec = bcd2bin(date[RX8581_REG_SC] & 0x7F);119 tm->tm_min = bcd2bin(date[RX8581_REG_MN] & 0x7F);120 tm->tm_hour = bcd2bin(date[RX8581_REG_HR] & 0x3F); /* rtc hr 0-23 */121 tm->tm_wday = ilog2(date[RX8581_REG_DW] & 0x7F);122 tm->tm_mday = bcd2bin(date[RX8581_REG_DM] & 0x3F);123 tm->tm_mon = bcd2bin(date[RX8581_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */124 tm->tm_year = bcd2bin(date[RX8581_REG_YR]) + 100;125 126 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, "127 "mday=%d, mon=%d, year=%d, wday=%d\n",128 __func__,129 tm->tm_sec, tm->tm_min, tm->tm_hour,130 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);131 132 return 0;133}134 135static int rx8581_rtc_set_time(struct device *dev, struct rtc_time *tm)136{137 struct i2c_client *client = to_i2c_client(dev);138 int err;139 unsigned char buf[7];140 struct rx8581 *rx8581 = i2c_get_clientdata(client);141 142 dev_dbg(dev, "%s: secs=%d, mins=%d, hours=%d, "143 "mday=%d, mon=%d, year=%d, wday=%d\n",144 __func__,145 tm->tm_sec, tm->tm_min, tm->tm_hour,146 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday);147 148 /* hours, minutes and seconds */149 buf[RX8581_REG_SC] = bin2bcd(tm->tm_sec);150 buf[RX8581_REG_MN] = bin2bcd(tm->tm_min);151 buf[RX8581_REG_HR] = bin2bcd(tm->tm_hour);152 153 buf[RX8581_REG_DM] = bin2bcd(tm->tm_mday);154 155 /* month, 1 - 12 */156 buf[RX8581_REG_MO] = bin2bcd(tm->tm_mon + 1);157 158 /* year and century */159 buf[RX8581_REG_YR] = bin2bcd(tm->tm_year - 100);160 buf[RX8581_REG_DW] = (0x1 << tm->tm_wday);161 162 /* Stop the clock */163 err = regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,164 RX8581_CTRL_STOP, RX8581_CTRL_STOP);165 if (err < 0)166 return err;167 168 /* write register's data */169 err = regmap_bulk_write(rx8581->regmap, RX8581_REG_SC,170 buf, sizeof(buf));171 if (err < 0)172 return err;173 174 /* get VLF and clear it */175 err = regmap_update_bits(rx8581->regmap, RX8581_REG_FLAG,176 RX8581_FLAG_VLF, 0);177 if (err < 0)178 return err;179 180 /* Restart the clock */181 return regmap_update_bits(rx8581->regmap, RX8581_REG_CTRL,182 RX8581_CTRL_STOP, 0);183}184 185static const struct rtc_class_ops rx8581_rtc_ops = {186 .read_time = rx8581_rtc_read_time,187 .set_time = rx8581_rtc_set_time,188};189 190static int rx8571_nvram_read(void *priv, unsigned int offset, void *val,191 size_t bytes)192{193 struct rx8581 *rx8581 = priv;194 195 return regmap_bulk_read(rx8581->regmap, RX8571_USER_RAM + offset,196 val, bytes);197}198 199static int rx8571_nvram_write(void *priv, unsigned int offset, void *val,200 size_t bytes)201{202 struct rx8581 *rx8581 = priv;203 204 return regmap_bulk_write(rx8581->regmap, RX8571_USER_RAM + offset,205 val, bytes);206}207 208static int rx85x1_nvram_read(void *priv, unsigned int offset, void *val,209 size_t bytes)210{211 struct rx8581 *rx8581 = priv;212 unsigned int tmp_val;213 int ret;214 215 ret = regmap_read(rx8581->regmap, RX8581_REG_RAM, &tmp_val);216 (*(unsigned char *)val) = (unsigned char) tmp_val;217 218 return ret;219}220 221static int rx85x1_nvram_write(void *priv, unsigned int offset, void *val,222 size_t bytes)223{224 struct rx8581 *rx8581 = priv;225 unsigned char tmp_val;226 227 tmp_val = *((unsigned char *)val);228 return regmap_write(rx8581->regmap, RX8581_REG_RAM,229 (unsigned int)tmp_val);230}231 232static const struct rx85x1_config rx8581_config = {233 .regmap = {234 .reg_bits = 8,235 .val_bits = 8,236 .max_register = 0xf,237 },238 .num_nvram = 1239};240 241static const struct rx85x1_config rx8571_config = {242 .regmap = {243 .reg_bits = 8,244 .val_bits = 8,245 .max_register = 0x1f,246 },247 .num_nvram = 2248};249 250static int rx8581_probe(struct i2c_client *client)251{252 struct rx8581 *rx8581;253 const struct rx85x1_config *config = &rx8581_config;254 const void *data = of_device_get_match_data(&client->dev);255 static struct nvmem_config nvmem_cfg[] = {256 {257 .name = "rx85x1-",258 .word_size = 1,259 .stride = 1,260 .size = 1,261 .reg_read = rx85x1_nvram_read,262 .reg_write = rx85x1_nvram_write,263 }, {264 .name = "rx8571-",265 .word_size = 1,266 .stride = 1,267 .size = RX8571_NVRAM_SIZE,268 .reg_read = rx8571_nvram_read,269 .reg_write = rx8571_nvram_write,270 },271 };272 int ret, i;273 274 dev_dbg(&client->dev, "%s\n", __func__);275 276 if (data)277 config = data;278 279 rx8581 = devm_kzalloc(&client->dev, sizeof(struct rx8581), GFP_KERNEL);280 if (!rx8581)281 return -ENOMEM;282 283 i2c_set_clientdata(client, rx8581);284 285 rx8581->regmap = devm_regmap_init_i2c(client, &config->regmap);286 if (IS_ERR(rx8581->regmap))287 return PTR_ERR(rx8581->regmap);288 289 rx8581->rtc = devm_rtc_allocate_device(&client->dev);290 if (IS_ERR(rx8581->rtc))291 return PTR_ERR(rx8581->rtc);292 293 rx8581->rtc->ops = &rx8581_rtc_ops;294 rx8581->rtc->range_min = RTC_TIMESTAMP_BEGIN_2000;295 rx8581->rtc->range_max = RTC_TIMESTAMP_END_2099;296 rx8581->rtc->start_secs = 0;297 rx8581->rtc->set_start_time = true;298 299 ret = devm_rtc_register_device(rx8581->rtc);300 301 for (i = 0; i < config->num_nvram; i++) {302 nvmem_cfg[i].priv = rx8581;303 devm_rtc_nvmem_register(rx8581->rtc, &nvmem_cfg[i]);304 }305 306 return ret;307}308 309static const struct i2c_device_id rx8581_id[] = {310 { "rx8581" },311 { }312};313MODULE_DEVICE_TABLE(i2c, rx8581_id);314 315static const __maybe_unused struct of_device_id rx8581_of_match[] = {316 { .compatible = "epson,rx8571", .data = &rx8571_config },317 { .compatible = "epson,rx8581", .data = &rx8581_config },318 { /* sentinel */ }319};320MODULE_DEVICE_TABLE(of, rx8581_of_match);321 322static struct i2c_driver rx8581_driver = {323 .driver = {324 .name = "rtc-rx8581",325 .of_match_table = of_match_ptr(rx8581_of_match),326 },327 .probe = rx8581_probe,328 .id_table = rx8581_id,329};330 331module_i2c_driver(rx8581_driver);332 333MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");334MODULE_DESCRIPTION("Epson RX-8571/RX-8581 RTC driver");335MODULE_LICENSE("GPL");336