1 /* 2 * An SPI driver for the Philips PCF2123 RTC 3 * Copyright 2009 Cyber Switching, Inc. 4 * 5 * Author: Chris Verges <chrisv@cyberswitching.com> 6 * Maintainers: http://www.cyberswitching.com 7 * 8 * based on the RS5C348 driver in this same directory. 9 * 10 * Thanks to Christian Pellegrin <chripell@fsfe.org> for 11 * the sysfs contributions to this driver. 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 version 2 as 15 * published by the Free Software Foundation. 16 * 17 * Please note that the CS is active high, so platform data 18 * should look something like: 19 * 20 * static struct spi_board_info ek_spi_devices[] = { 21 * ... 22 * { 23 * .modalias = "rtc-pcf2123", 24 * .chip_select = 1, 25 * .controller_data = (void *)AT91_PIN_PA10, 26 * .max_speed_hz = 1000 * 1000, 27 * .mode = SPI_CS_HIGH, 28 * .bus_num = 0, 29 * }, 30 * ... 31 *}; 32 * 33 */ 34 35 #include <linux/bcd.h> 36 #include <linux/delay.h> 37 #include <linux/device.h> 38 #include <linux/errno.h> 39 #include <linux/init.h> 40 #include <linux/kernel.h> 41 #include <linux/string.h> 42 #include <linux/rtc.h> 43 #include <linux/spi/spi.h> 44 45 #define DRV_VERSION "0.6" 46 47 #define PCF2123_REG_CTRL1 (0x00) /* Control Register 1 */ 48 #define PCF2123_REG_CTRL2 (0x01) /* Control Register 2 */ 49 #define PCF2123_REG_SC (0x02) /* datetime */ 50 #define PCF2123_REG_MN (0x03) 51 #define PCF2123_REG_HR (0x04) 52 #define PCF2123_REG_DM (0x05) 53 #define PCF2123_REG_DW (0x06) 54 #define PCF2123_REG_MO (0x07) 55 #define PCF2123_REG_YR (0x08) 56 57 #define PCF2123_SUBADDR (1 << 4) 58 #define PCF2123_WRITE ((0 << 7) | PCF2123_SUBADDR) 59 #define PCF2123_READ ((1 << 7) | PCF2123_SUBADDR) 60 61 static struct spi_driver pcf2123_driver; 62 63 struct pcf2123_sysfs_reg { 64 struct device_attribute attr; 65 char name[2]; 66 }; 67 68 struct pcf2123_plat_data { 69 struct rtc_device *rtc; 70 struct pcf2123_sysfs_reg regs[16]; 71 }; 72 73 /* 74 * Causes a 30 nanosecond delay to ensure that the PCF2123 chip select 75 * is released properly after an SPI write. This function should be 76 * called after EVERY read/write call over SPI. 77 */ 78 static inline void pcf2123_delay_trec(void) 79 { 80 ndelay(30); 81 } 82 83 static ssize_t pcf2123_show(struct device *dev, struct device_attribute *attr, 84 char *buffer) 85 { 86 struct spi_device *spi = to_spi_device(dev); 87 struct pcf2123_sysfs_reg *r; 88 u8 txbuf[1], rxbuf[1]; 89 unsigned long reg; 90 int ret; 91 92 r = container_of(attr, struct pcf2123_sysfs_reg, attr); 93 94 if (strict_strtoul(r->name, 16, ®)) 95 return -EINVAL; 96 97 txbuf[0] = PCF2123_READ | reg; 98 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1); 99 if (ret < 0) 100 return -EIO; 101 pcf2123_delay_trec(); 102 return sprintf(buffer, "0x%x\n", rxbuf[0]); 103 } 104 105 static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr, 106 const char *buffer, size_t count) { 107 struct spi_device *spi = to_spi_device(dev); 108 struct pcf2123_sysfs_reg *r; 109 u8 txbuf[2]; 110 unsigned long reg; 111 unsigned long val; 112 113 int ret; 114 115 r = container_of(attr, struct pcf2123_sysfs_reg, attr); 116 117 if (strict_strtoul(r->name, 16, ®) 118 || strict_strtoul(buffer, 10, &val)) 119 return -EINVAL; 120 121 txbuf[0] = PCF2123_WRITE | reg; 122 txbuf[1] = val; 123 ret = spi_write(spi, txbuf, sizeof(txbuf)); 124 if (ret < 0) 125 return -EIO; 126 pcf2123_delay_trec(); 127 return count; 128 } 129 130 static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm) 131 { 132 struct spi_device *spi = to_spi_device(dev); 133 u8 txbuf[1], rxbuf[7]; 134 int ret; 135 136 txbuf[0] = PCF2123_READ | PCF2123_REG_SC; 137 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), 138 rxbuf, sizeof(rxbuf)); 139 if (ret < 0) 140 return ret; 141 pcf2123_delay_trec(); 142 143 tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F); 144 tm->tm_min = bcd2bin(rxbuf[1] & 0x7F); 145 tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F); /* rtc hr 0-23 */ 146 tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F); 147 tm->tm_wday = rxbuf[4] & 0x07; 148 tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1; /* rtc mn 1-12 */ 149 tm->tm_year = bcd2bin(rxbuf[6]); 150 if (tm->tm_year < 70) 151 tm->tm_year += 100; /* assume we are in 1970...2069 */ 152 153 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 154 "mday=%d, mon=%d, year=%d, wday=%d\n", 155 __func__, 156 tm->tm_sec, tm->tm_min, tm->tm_hour, 157 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 158 159 /* the clock can give out invalid datetime, but we cannot return 160 * -EINVAL otherwise hwclock will refuse to set the time on bootup. 161 */ 162 if (rtc_valid_tm(tm) < 0) 163 dev_err(dev, "retrieved date/time is not valid.\n"); 164 165 return 0; 166 } 167 168 static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm) 169 { 170 struct spi_device *spi = to_spi_device(dev); 171 u8 txbuf[8]; 172 int ret; 173 174 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 175 "mday=%d, mon=%d, year=%d, wday=%d\n", 176 __func__, 177 tm->tm_sec, tm->tm_min, tm->tm_hour, 178 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 179 180 /* Stop the counter first */ 181 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 182 txbuf[1] = 0x20; 183 ret = spi_write(spi, txbuf, 2); 184 if (ret < 0) 185 return ret; 186 pcf2123_delay_trec(); 187 188 /* Set the new time */ 189 txbuf[0] = PCF2123_WRITE | PCF2123_REG_SC; 190 txbuf[1] = bin2bcd(tm->tm_sec & 0x7F); 191 txbuf[2] = bin2bcd(tm->tm_min & 0x7F); 192 txbuf[3] = bin2bcd(tm->tm_hour & 0x3F); 193 txbuf[4] = bin2bcd(tm->tm_mday & 0x3F); 194 txbuf[5] = tm->tm_wday & 0x07; 195 txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */ 196 txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100); 197 198 ret = spi_write(spi, txbuf, sizeof(txbuf)); 199 if (ret < 0) 200 return ret; 201 pcf2123_delay_trec(); 202 203 /* Start the counter */ 204 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 205 txbuf[1] = 0x00; 206 ret = spi_write(spi, txbuf, 2); 207 if (ret < 0) 208 return ret; 209 pcf2123_delay_trec(); 210 211 return 0; 212 } 213 214 static const struct rtc_class_ops pcf2123_rtc_ops = { 215 .read_time = pcf2123_rtc_read_time, 216 .set_time = pcf2123_rtc_set_time, 217 }; 218 219 static int __devinit pcf2123_probe(struct spi_device *spi) 220 { 221 struct rtc_device *rtc; 222 struct pcf2123_plat_data *pdata; 223 u8 txbuf[2], rxbuf[2]; 224 int ret, i; 225 226 pdata = kzalloc(sizeof(struct pcf2123_plat_data), GFP_KERNEL); 227 if (!pdata) 228 return -ENOMEM; 229 spi->dev.platform_data = pdata; 230 231 /* Send a software reset command */ 232 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 233 txbuf[1] = 0x58; 234 dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n", 235 txbuf[0], txbuf[1]); 236 ret = spi_write(spi, txbuf, 2 * sizeof(u8)); 237 if (ret < 0) 238 goto kfree_exit; 239 pcf2123_delay_trec(); 240 241 /* Stop the counter */ 242 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 243 txbuf[1] = 0x20; 244 dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n", 245 txbuf[0], txbuf[1]); 246 ret = spi_write(spi, txbuf, 2 * sizeof(u8)); 247 if (ret < 0) 248 goto kfree_exit; 249 pcf2123_delay_trec(); 250 251 /* See if the counter was actually stopped */ 252 txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1; 253 dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n", 254 txbuf[0]); 255 ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8), 256 rxbuf, 2 * sizeof(u8)); 257 dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n", 258 rxbuf[0], rxbuf[1]); 259 if (ret < 0) 260 goto kfree_exit; 261 pcf2123_delay_trec(); 262 263 if (!(rxbuf[0] & 0x20)) { 264 dev_err(&spi->dev, "chip not found\n"); 265 goto kfree_exit; 266 } 267 268 dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n"); 269 dev_info(&spi->dev, "spiclk %u KHz.\n", 270 (spi->max_speed_hz + 500) / 1000); 271 272 /* Start the counter */ 273 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 274 txbuf[1] = 0x00; 275 ret = spi_write(spi, txbuf, sizeof(txbuf)); 276 if (ret < 0) 277 goto kfree_exit; 278 pcf2123_delay_trec(); 279 280 /* Finalize the initialization */ 281 rtc = rtc_device_register(pcf2123_driver.driver.name, &spi->dev, 282 &pcf2123_rtc_ops, THIS_MODULE); 283 284 if (IS_ERR(rtc)) { 285 dev_err(&spi->dev, "failed to register.\n"); 286 ret = PTR_ERR(rtc); 287 goto kfree_exit; 288 } 289 290 pdata->rtc = rtc; 291 292 for (i = 0; i < 16; i++) { 293 sprintf(pdata->regs[i].name, "%1x", i); 294 pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR; 295 pdata->regs[i].attr.attr.name = pdata->regs[i].name; 296 pdata->regs[i].attr.show = pcf2123_show; 297 pdata->regs[i].attr.store = pcf2123_store; 298 ret = device_create_file(&spi->dev, &pdata->regs[i].attr); 299 if (ret) { 300 dev_err(&spi->dev, "Unable to create sysfs %s\n", 301 pdata->regs[i].name); 302 goto sysfs_exit; 303 } 304 } 305 306 return 0; 307 308 sysfs_exit: 309 for (i--; i >= 0; i--) 310 device_remove_file(&spi->dev, &pdata->regs[i].attr); 311 312 kfree_exit: 313 kfree(pdata); 314 spi->dev.platform_data = NULL; 315 return ret; 316 } 317 318 static int __devexit pcf2123_remove(struct spi_device *spi) 319 { 320 struct pcf2123_plat_data *pdata = spi->dev.platform_data; 321 int i; 322 323 if (pdata) { 324 struct rtc_device *rtc = pdata->rtc; 325 326 if (rtc) 327 rtc_device_unregister(rtc); 328 for (i = 0; i < 16; i++) 329 if (pdata->regs[i].name[0]) 330 device_remove_file(&spi->dev, 331 &pdata->regs[i].attr); 332 kfree(pdata); 333 } 334 335 return 0; 336 } 337 338 static struct spi_driver pcf2123_driver = { 339 .driver = { 340 .name = "rtc-pcf2123", 341 .bus = &spi_bus_type, 342 .owner = THIS_MODULE, 343 }, 344 .probe = pcf2123_probe, 345 .remove = __devexit_p(pcf2123_remove), 346 }; 347 348 static int __init pcf2123_init(void) 349 { 350 return spi_register_driver(&pcf2123_driver); 351 } 352 353 static void __exit pcf2123_exit(void) 354 { 355 spi_unregister_driver(&pcf2123_driver); 356 } 357 358 MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>"); 359 MODULE_DESCRIPTION("NXP PCF2123 RTC driver"); 360 MODULE_LICENSE("GPL"); 361 MODULE_VERSION(DRV_VERSION); 362 363 module_init(pcf2123_init); 364 module_exit(pcf2123_exit); 365