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