1 /* 2 * SII Semiconductor Corporation S35392A RTC driver. 3 * 4 * Copyright (c) 2017, General Electric Company 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms and conditions of the GNU General Public License, 8 * version 2, as published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 13 * more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program. If not, see <http://www.gnu.org/licenses/>. 17 * 18 * SPDX-License-Identifier: GPL-2.0 19 */ 20 21 #include <command.h> 22 #include <common.h> 23 #include <dm.h> 24 #include <i2c.h> 25 #include <linux/bitrev.h> 26 #include <rtc.h> 27 28 #define S35390A_CMD_STATUS1 0x30 29 #define S35390A_CMD_STATUS2 0x31 30 #define S35390A_CMD_TIME1 0x32 31 #define S35390A_CMD_TIME2 0x33 32 #define S35390A_CMD_INT2_REG1 0x35 33 34 #define S35390A_BYTE_YEAR 0 35 #define S35390A_BYTE_MONTH 1 36 #define S35390A_BYTE_DAY 2 37 #define S35390A_BYTE_WDAY 3 38 #define S35390A_BYTE_HOURS 4 39 #define S35390A_BYTE_MINS 5 40 #define S35390A_BYTE_SECS 6 41 42 /* flags for STATUS1 */ 43 #define S35390A_FLAG_POC 0x01 44 #define S35390A_FLAG_BLD 0x02 45 #define S35390A_FLAG_INT2 0x04 46 #define S35390A_FLAG_24H 0x40 47 #define S35390A_FLAG_RESET 0x80 48 49 /* 50 * If either BLD or POC is set, then the chip has lost power long enough for 51 * the time value to become invalid. 52 */ 53 #define S35390A_LOW_VOLTAGE (S35390A_FLAG_POC | S35390A_FLAG_BLD) 54 55 /*---------------------------------------------------------------------*/ 56 #undef DEBUG_RTC 57 58 #ifdef DEBUG_RTC 59 #define DEBUGR(fmt, args...) printf(fmt, ##args) 60 #else 61 #define DEBUGR(fmt, args...) 62 #endif 63 /*---------------------------------------------------------------------*/ 64 65 #ifdef CONFIG_DM_RTC 66 #define DEV_TYPE struct udevice 67 #else 68 /* Local udevice */ 69 struct ludevice { 70 u8 chip; 71 }; 72 73 #define DEV_TYPE struct ludevice 74 struct ludevice dev; 75 76 #endif 77 78 #define msleep(a) udelay(a * 1000) 79 80 int lowvoltage; 81 82 static int s35392a_rtc_reset(DEV_TYPE *dev); 83 84 static int s35392a_rtc_read(DEV_TYPE *dev, u8 reg, u8 *buf, int len) 85 { 86 int ret; 87 88 #ifdef CONFIG_DM_RTC 89 /* TODO: we need to tweak the chip address to reg */ 90 ret = dm_i2c_read(dev, 0, buf, len); 91 #else 92 (void)dev; 93 ret = i2c_read(reg, 0, -1, buf, len); 94 #endif 95 96 return ret; 97 } 98 99 static int s35392a_rtc_write(DEV_TYPE *dev, u8 reg, u8 *buf, int len) 100 { 101 int ret; 102 103 #ifdef CONFIG_DM_RTC 104 /* TODO: we need to tweak the chip address to reg */ 105 ret = dm_i2c_write(dev, 0, buf, 1); 106 #else 107 (void)dev; 108 ret = i2c_write(reg, 0, 0, buf, len); 109 #endif 110 111 return ret; 112 } 113 114 static int s35392a_rtc_read8(DEV_TYPE *dev, unsigned int reg) 115 { 116 u8 val; 117 int ret; 118 119 ret = s35392a_rtc_read(dev, reg, &val, sizeof(val)); 120 return ret < 0 ? ret : val; 121 } 122 123 static int s35392a_rtc_write8(DEV_TYPE *dev, unsigned int reg, int val) 124 { 125 int ret; 126 u8 lval = val; 127 128 ret = s35392a_rtc_write(dev, reg, &lval, sizeof(lval)); 129 return ret < 0 ? ret : 0; 130 } 131 132 static int validate_time(const struct rtc_time *tm) 133 { 134 if ((tm->tm_year < 2000) || (tm->tm_year > 2099)) 135 return -EINVAL; 136 137 if ((tm->tm_mon < 1) || (tm->tm_mon > 12)) 138 return -EINVAL; 139 140 if ((tm->tm_mday < 1) || (tm->tm_mday > 31)) 141 return -EINVAL; 142 143 if ((tm->tm_wday < 0) || (tm->tm_wday > 6)) 144 return -EINVAL; 145 146 if ((tm->tm_hour < 0) || (tm->tm_hour > 23)) 147 return -EINVAL; 148 149 if ((tm->tm_min < 0) || (tm->tm_min > 59)) 150 return -EINVAL; 151 152 if ((tm->tm_sec < 0) || (tm->tm_sec > 59)) 153 return -EINVAL; 154 155 return 0; 156 } 157 158 void s35392a_rtc_init(DEV_TYPE *dev) 159 { 160 int status; 161 162 status = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1); 163 if (status < 0) 164 goto error; 165 166 DEBUGR("init: S35390A_CMD_STATUS1: 0x%x\n", status); 167 168 lowvoltage = status & S35390A_LOW_VOLTAGE ? 1 : 0; 169 170 if (status & S35390A_FLAG_POC) 171 /* 172 * Do not communicate for 0.5 seconds since the power-on 173 * detection circuit is in operation. 174 */ 175 msleep(500); 176 177 else if (!lowvoltage) 178 /* 179 * If both POC and BLD are unset everything is fine. 180 */ 181 return; 182 183 if (lowvoltage) 184 printf("RTC low voltage detected\n"); 185 186 if (!s35392a_rtc_reset(dev)) 187 return; 188 189 error: 190 printf("Error RTC init.\n"); 191 } 192 193 /* Get the current time from the RTC */ 194 static int s35392a_rtc_get(DEV_TYPE *dev, struct rtc_time *tm) 195 { 196 u8 date[7]; 197 int ret, i; 198 199 if (lowvoltage) { 200 DEBUGR("RTC low voltage detected\n"); 201 return -EINVAL; 202 } 203 204 ret = s35392a_rtc_read(dev, S35390A_CMD_TIME1, date, sizeof(date)); 205 if (ret < 0) { 206 DEBUGR("Error reading date from RTC\n"); 207 return -EIO; 208 } 209 210 /* This chip returns the bits of each byte in reverse order */ 211 for (i = 0; i < 7; ++i) 212 date[i] = bitrev8(date[i]); 213 214 tm->tm_sec = bcd2bin(date[S35390A_BYTE_SECS]); 215 tm->tm_min = bcd2bin(date[S35390A_BYTE_MINS]); 216 tm->tm_hour = bcd2bin(date[S35390A_BYTE_HOURS] & ~S35390A_FLAG_24H); 217 tm->tm_wday = bcd2bin(date[S35390A_BYTE_WDAY]); 218 tm->tm_mday = bcd2bin(date[S35390A_BYTE_DAY]); 219 tm->tm_mon = bcd2bin(date[S35390A_BYTE_MONTH]); 220 tm->tm_year = bcd2bin(date[S35390A_BYTE_YEAR]) + 2000; 221 222 DEBUGR("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 223 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday, 224 tm->tm_hour, tm->tm_min, tm->tm_sec); 225 226 return 0; 227 } 228 229 /* Set the RTC */ 230 static int s35392a_rtc_set(DEV_TYPE *dev, const struct rtc_time *tm) 231 { 232 int i, ret; 233 int status; 234 u8 date[7]; 235 236 DEBUGR("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 237 tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_wday, 238 tm->tm_hour, tm->tm_min, tm->tm_sec); 239 240 ret = validate_time(tm); 241 if (ret < 0) 242 return -EINVAL; 243 244 /* We support only 24h mode */ 245 ret = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1); 246 if (ret < 0) 247 return -EIO; 248 status = ret; 249 250 ret = s35392a_rtc_write8(dev, S35390A_CMD_STATUS1, 251 status | S35390A_FLAG_24H); 252 if (ret < 0) 253 return -EIO; 254 255 date[S35390A_BYTE_YEAR] = bin2bcd(tm->tm_year - 2000); 256 date[S35390A_BYTE_MONTH] = bin2bcd(tm->tm_mon); 257 date[S35390A_BYTE_DAY] = bin2bcd(tm->tm_mday); 258 date[S35390A_BYTE_WDAY] = bin2bcd(tm->tm_wday); 259 date[S35390A_BYTE_HOURS] = bin2bcd(tm->tm_hour); 260 date[S35390A_BYTE_MINS] = bin2bcd(tm->tm_min); 261 date[S35390A_BYTE_SECS] = bin2bcd(tm->tm_sec); 262 263 /* This chip expects the bits of each byte to be in reverse order */ 264 for (i = 0; i < 7; ++i) 265 date[i] = bitrev8(date[i]); 266 267 ret = s35392a_rtc_write(dev, S35390A_CMD_TIME1, date, sizeof(date)); 268 if (ret < 0) { 269 DEBUGR("Error writing date to RTC\n"); 270 return -EIO; 271 } 272 273 /* Now we have time. Reset the low voltage status */ 274 lowvoltage = 0; 275 276 return 0; 277 } 278 279 /* Reset the RTC. */ 280 static int s35392a_rtc_reset(DEV_TYPE *dev) 281 { 282 int buf; 283 int ret; 284 unsigned int initcount = 0; 285 286 buf = S35390A_FLAG_RESET; 287 288 initialize: 289 ret = s35392a_rtc_write8(dev, S35390A_CMD_STATUS1, buf); 290 if (ret < 0) 291 return -EIO; 292 293 ret = s35392a_rtc_read8(dev, S35390A_CMD_STATUS1); 294 if (ret < 0) 295 return -EIO; 296 buf = ret; 297 298 if (!lowvoltage) 299 lowvoltage = buf & S35390A_LOW_VOLTAGE ? 1 : 0; 300 301 if (buf & S35390A_LOW_VOLTAGE) { 302 /* Try up to five times to reset the chip */ 303 if (initcount < 5) { 304 ++initcount; 305 goto initialize; 306 } else { 307 return -EIO; 308 } 309 } 310 311 return 0; 312 } 313 314 #ifndef CONFIG_DM_RTC 315 316 int rtc_get(struct rtc_time *tm) 317 { 318 return s35392a_rtc_get(&dev, tm); 319 } 320 321 int rtc_set(struct rtc_time *tm) 322 { 323 return s35392a_rtc_set(&dev, tm); 324 } 325 326 void rtc_reset(void) 327 { 328 s35392a_rtc_reset(&dev); 329 } 330 331 void rtc_init(void) 332 { 333 s35392a_rtc_init(&dev); 334 } 335 336 #else 337 338 static int s35392a_probe(struct udevice *dev) 339 { 340 s35392a_rtc_init(dev); 341 return 0; 342 } 343 344 static const struct rtc_ops s35392a_rtc_ops = { 345 .get = s35392a_rtc_get, 346 .set = s35392a_rtc_set, 347 .read8 = s35392a_rtc_read8, 348 .write8 = s35392a_rtc_write8, 349 .reset = s35392a_rtc_reset, 350 }; 351 352 static const struct udevice_id s35392a_rtc_ids[] = { 353 { .compatible = "sii,s35392a-rtc" }, 354 { } 355 }; 356 357 U_BOOT_DRIVER(s35392a_rtc) = { 358 .name = "s35392a_rtc", 359 .id = UCLASS_RTC, 360 .probe = s35392a_probe, 361 .of_match = s35392a_rtc_ids, 362 .ops = &s35392a_rtc_ops, 363 }; 364 365 #endif 366