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 ret = kstrtoul(r->name, 16, ®); 98 if (ret) 99 return ret; 100 101 txbuf[0] = PCF2123_READ | reg; 102 ret = spi_write_then_read(spi, txbuf, 1, rxbuf, 1); 103 if (ret < 0) 104 return -EIO; 105 pcf2123_delay_trec(); 106 return sprintf(buffer, "0x%x\n", rxbuf[0]); 107 } 108 109 static ssize_t pcf2123_store(struct device *dev, struct device_attribute *attr, 110 const char *buffer, size_t count) { 111 struct spi_device *spi = to_spi_device(dev); 112 struct pcf2123_sysfs_reg *r; 113 u8 txbuf[2]; 114 unsigned long reg; 115 unsigned long val; 116 117 int ret; 118 119 r = container_of(attr, struct pcf2123_sysfs_reg, attr); 120 121 ret = kstrtoul(r->name, 16, ®); 122 if (ret) 123 return ret; 124 125 ret = kstrtoul(buffer, 10, &val); 126 if (ret) 127 return ret; 128 129 txbuf[0] = PCF2123_WRITE | reg; 130 txbuf[1] = val; 131 ret = spi_write(spi, txbuf, sizeof(txbuf)); 132 if (ret < 0) 133 return -EIO; 134 pcf2123_delay_trec(); 135 return count; 136 } 137 138 static int pcf2123_rtc_read_time(struct device *dev, struct rtc_time *tm) 139 { 140 struct spi_device *spi = to_spi_device(dev); 141 u8 txbuf[1], rxbuf[7]; 142 int ret; 143 144 txbuf[0] = PCF2123_READ | PCF2123_REG_SC; 145 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), 146 rxbuf, sizeof(rxbuf)); 147 if (ret < 0) 148 return ret; 149 pcf2123_delay_trec(); 150 151 tm->tm_sec = bcd2bin(rxbuf[0] & 0x7F); 152 tm->tm_min = bcd2bin(rxbuf[1] & 0x7F); 153 tm->tm_hour = bcd2bin(rxbuf[2] & 0x3F); /* rtc hr 0-23 */ 154 tm->tm_mday = bcd2bin(rxbuf[3] & 0x3F); 155 tm->tm_wday = rxbuf[4] & 0x07; 156 tm->tm_mon = bcd2bin(rxbuf[5] & 0x1F) - 1; /* rtc mn 1-12 */ 157 tm->tm_year = bcd2bin(rxbuf[6]); 158 if (tm->tm_year < 70) 159 tm->tm_year += 100; /* assume we are in 1970...2069 */ 160 161 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 162 "mday=%d, mon=%d, year=%d, wday=%d\n", 163 __func__, 164 tm->tm_sec, tm->tm_min, tm->tm_hour, 165 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 166 167 /* the clock can give out invalid datetime, but we cannot return 168 * -EINVAL otherwise hwclock will refuse to set the time on bootup. 169 */ 170 if (rtc_valid_tm(tm) < 0) 171 dev_err(dev, "retrieved date/time is not valid.\n"); 172 173 return 0; 174 } 175 176 static int pcf2123_rtc_set_time(struct device *dev, struct rtc_time *tm) 177 { 178 struct spi_device *spi = to_spi_device(dev); 179 u8 txbuf[8]; 180 int ret; 181 182 dev_dbg(dev, "%s: tm is secs=%d, mins=%d, hours=%d, " 183 "mday=%d, mon=%d, year=%d, wday=%d\n", 184 __func__, 185 tm->tm_sec, tm->tm_min, tm->tm_hour, 186 tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); 187 188 /* Stop the counter first */ 189 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 190 txbuf[1] = 0x20; 191 ret = spi_write(spi, txbuf, 2); 192 if (ret < 0) 193 return ret; 194 pcf2123_delay_trec(); 195 196 /* Set the new time */ 197 txbuf[0] = PCF2123_WRITE | PCF2123_REG_SC; 198 txbuf[1] = bin2bcd(tm->tm_sec & 0x7F); 199 txbuf[2] = bin2bcd(tm->tm_min & 0x7F); 200 txbuf[3] = bin2bcd(tm->tm_hour & 0x3F); 201 txbuf[4] = bin2bcd(tm->tm_mday & 0x3F); 202 txbuf[5] = tm->tm_wday & 0x07; 203 txbuf[6] = bin2bcd((tm->tm_mon + 1) & 0x1F); /* rtc mn 1-12 */ 204 txbuf[7] = bin2bcd(tm->tm_year < 100 ? tm->tm_year : tm->tm_year - 100); 205 206 ret = spi_write(spi, txbuf, sizeof(txbuf)); 207 if (ret < 0) 208 return ret; 209 pcf2123_delay_trec(); 210 211 /* Start the counter */ 212 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 213 txbuf[1] = 0x00; 214 ret = spi_write(spi, txbuf, 2); 215 if (ret < 0) 216 return ret; 217 pcf2123_delay_trec(); 218 219 return 0; 220 } 221 222 static const struct rtc_class_ops pcf2123_rtc_ops = { 223 .read_time = pcf2123_rtc_read_time, 224 .set_time = pcf2123_rtc_set_time, 225 }; 226 227 static int pcf2123_probe(struct spi_device *spi) 228 { 229 struct rtc_device *rtc; 230 struct pcf2123_plat_data *pdata; 231 u8 txbuf[2], rxbuf[2]; 232 int ret, i; 233 234 pdata = devm_kzalloc(&spi->dev, sizeof(struct pcf2123_plat_data), 235 GFP_KERNEL); 236 if (!pdata) 237 return -ENOMEM; 238 spi->dev.platform_data = pdata; 239 240 /* Send a software reset command */ 241 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 242 txbuf[1] = 0x58; 243 dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n", 244 txbuf[0], txbuf[1]); 245 ret = spi_write(spi, txbuf, 2 * sizeof(u8)); 246 if (ret < 0) 247 goto kfree_exit; 248 pcf2123_delay_trec(); 249 250 /* Stop the counter */ 251 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 252 txbuf[1] = 0x20; 253 dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n", 254 txbuf[0], txbuf[1]); 255 ret = spi_write(spi, txbuf, 2 * sizeof(u8)); 256 if (ret < 0) 257 goto kfree_exit; 258 pcf2123_delay_trec(); 259 260 /* See if the counter was actually stopped */ 261 txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1; 262 dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n", 263 txbuf[0]); 264 ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8), 265 rxbuf, 2 * sizeof(u8)); 266 dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n", 267 rxbuf[0], rxbuf[1]); 268 if (ret < 0) 269 goto kfree_exit; 270 pcf2123_delay_trec(); 271 272 if (!(rxbuf[0] & 0x20)) { 273 dev_err(&spi->dev, "chip not found\n"); 274 ret = -ENODEV; 275 goto kfree_exit; 276 } 277 278 dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n"); 279 dev_info(&spi->dev, "spiclk %u KHz.\n", 280 (spi->max_speed_hz + 500) / 1000); 281 282 /* Start the counter */ 283 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 284 txbuf[1] = 0x00; 285 ret = spi_write(spi, txbuf, sizeof(txbuf)); 286 if (ret < 0) 287 goto kfree_exit; 288 pcf2123_delay_trec(); 289 290 /* Finalize the initialization */ 291 rtc = devm_rtc_device_register(&spi->dev, pcf2123_driver.driver.name, 292 &pcf2123_rtc_ops, THIS_MODULE); 293 294 if (IS_ERR(rtc)) { 295 dev_err(&spi->dev, "failed to register.\n"); 296 ret = PTR_ERR(rtc); 297 goto kfree_exit; 298 } 299 300 pdata->rtc = rtc; 301 302 for (i = 0; i < 16; i++) { 303 sysfs_attr_init(&pdata->regs[i].attr.attr); 304 sprintf(pdata->regs[i].name, "%1x", i); 305 pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR; 306 pdata->regs[i].attr.attr.name = pdata->regs[i].name; 307 pdata->regs[i].attr.show = pcf2123_show; 308 pdata->regs[i].attr.store = pcf2123_store; 309 ret = device_create_file(&spi->dev, &pdata->regs[i].attr); 310 if (ret) { 311 dev_err(&spi->dev, "Unable to create sysfs %s\n", 312 pdata->regs[i].name); 313 goto sysfs_exit; 314 } 315 } 316 317 return 0; 318 319 sysfs_exit: 320 for (i--; i >= 0; i--) 321 device_remove_file(&spi->dev, &pdata->regs[i].attr); 322 323 kfree_exit: 324 spi->dev.platform_data = NULL; 325 return ret; 326 } 327 328 static int pcf2123_remove(struct spi_device *spi) 329 { 330 struct pcf2123_plat_data *pdata = dev_get_platdata(&spi->dev); 331 int i; 332 333 if (pdata) { 334 for (i = 0; i < 16; i++) 335 if (pdata->regs[i].name[0]) 336 device_remove_file(&spi->dev, 337 &pdata->regs[i].attr); 338 } 339 340 return 0; 341 } 342 343 static struct spi_driver pcf2123_driver = { 344 .driver = { 345 .name = "rtc-pcf2123", 346 .owner = THIS_MODULE, 347 }, 348 .probe = pcf2123_probe, 349 .remove = pcf2123_remove, 350 }; 351 352 module_spi_driver(pcf2123_driver); 353 354 MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>"); 355 MODULE_DESCRIPTION("NXP PCF2123 RTC driver"); 356 MODULE_LICENSE("GPL"); 357 MODULE_VERSION(DRV_VERSION); 358