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 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 = devm_kzalloc(&spi->dev, sizeof(struct pcf2123_plat_data), 230 GFP_KERNEL); 231 if (!pdata) 232 return -ENOMEM; 233 spi->dev.platform_data = pdata; 234 235 /* Send a software reset command */ 236 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 237 txbuf[1] = 0x58; 238 dev_dbg(&spi->dev, "resetting RTC (0x%02X 0x%02X)\n", 239 txbuf[0], txbuf[1]); 240 ret = spi_write(spi, txbuf, 2 * sizeof(u8)); 241 if (ret < 0) 242 goto kfree_exit; 243 pcf2123_delay_trec(); 244 245 /* Stop the counter */ 246 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 247 txbuf[1] = 0x20; 248 dev_dbg(&spi->dev, "stopping RTC (0x%02X 0x%02X)\n", 249 txbuf[0], txbuf[1]); 250 ret = spi_write(spi, txbuf, 2 * sizeof(u8)); 251 if (ret < 0) 252 goto kfree_exit; 253 pcf2123_delay_trec(); 254 255 /* See if the counter was actually stopped */ 256 txbuf[0] = PCF2123_READ | PCF2123_REG_CTRL1; 257 dev_dbg(&spi->dev, "checking for presence of RTC (0x%02X)\n", 258 txbuf[0]); 259 ret = spi_write_then_read(spi, txbuf, 1 * sizeof(u8), 260 rxbuf, 2 * sizeof(u8)); 261 dev_dbg(&spi->dev, "received data from RTC (0x%02X 0x%02X)\n", 262 rxbuf[0], rxbuf[1]); 263 if (ret < 0) 264 goto kfree_exit; 265 pcf2123_delay_trec(); 266 267 if (!(rxbuf[0] & 0x20)) { 268 dev_err(&spi->dev, "chip not found\n"); 269 ret = -ENODEV; 270 goto kfree_exit; 271 } 272 273 dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n"); 274 dev_info(&spi->dev, "spiclk %u KHz.\n", 275 (spi->max_speed_hz + 500) / 1000); 276 277 /* Start the counter */ 278 txbuf[0] = PCF2123_WRITE | PCF2123_REG_CTRL1; 279 txbuf[1] = 0x00; 280 ret = spi_write(spi, txbuf, sizeof(txbuf)); 281 if (ret < 0) 282 goto kfree_exit; 283 pcf2123_delay_trec(); 284 285 /* Finalize the initialization */ 286 rtc = devm_rtc_device_register(&spi->dev, pcf2123_driver.driver.name, 287 &pcf2123_rtc_ops, THIS_MODULE); 288 289 if (IS_ERR(rtc)) { 290 dev_err(&spi->dev, "failed to register.\n"); 291 ret = PTR_ERR(rtc); 292 goto kfree_exit; 293 } 294 295 pdata->rtc = rtc; 296 297 for (i = 0; i < 16; i++) { 298 sysfs_attr_init(&pdata->regs[i].attr.attr); 299 sprintf(pdata->regs[i].name, "%1x", i); 300 pdata->regs[i].attr.attr.mode = S_IRUGO | S_IWUSR; 301 pdata->regs[i].attr.attr.name = pdata->regs[i].name; 302 pdata->regs[i].attr.show = pcf2123_show; 303 pdata->regs[i].attr.store = pcf2123_store; 304 ret = device_create_file(&spi->dev, &pdata->regs[i].attr); 305 if (ret) { 306 dev_err(&spi->dev, "Unable to create sysfs %s\n", 307 pdata->regs[i].name); 308 goto sysfs_exit; 309 } 310 } 311 312 return 0; 313 314 sysfs_exit: 315 for (i--; i >= 0; i--) 316 device_remove_file(&spi->dev, &pdata->regs[i].attr); 317 318 kfree_exit: 319 spi->dev.platform_data = NULL; 320 return ret; 321 } 322 323 static int pcf2123_remove(struct spi_device *spi) 324 { 325 struct pcf2123_plat_data *pdata = spi->dev.platform_data; 326 int i; 327 328 if (pdata) { 329 for (i = 0; i < 16; i++) 330 if (pdata->regs[i].name[0]) 331 device_remove_file(&spi->dev, 332 &pdata->regs[i].attr); 333 } 334 335 return 0; 336 } 337 338 static struct spi_driver pcf2123_driver = { 339 .driver = { 340 .name = "rtc-pcf2123", 341 .owner = THIS_MODULE, 342 }, 343 .probe = pcf2123_probe, 344 .remove = pcf2123_remove, 345 }; 346 347 module_spi_driver(pcf2123_driver); 348 349 MODULE_AUTHOR("Chris Verges <chrisv@cyberswitching.com>"); 350 MODULE_DESCRIPTION("NXP PCF2123 RTC driver"); 351 MODULE_LICENSE("GPL"); 352 MODULE_VERSION(DRV_VERSION); 353