1 /* 2 * A SPI driver for the Ricoh RS5C348 RTC 3 * 4 * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 * The board specific init code should provide characteristics of this 11 * device: 12 * Mode 1 (High-Active, Shift-Then-Sample), High Avtive CS 13 */ 14 15 #include <linux/bcd.h> 16 #include <linux/delay.h> 17 #include <linux/device.h> 18 #include <linux/errno.h> 19 #include <linux/init.h> 20 #include <linux/kernel.h> 21 #include <linux/string.h> 22 #include <linux/slab.h> 23 #include <linux/rtc.h> 24 #include <linux/workqueue.h> 25 #include <linux/spi/spi.h> 26 #include <linux/module.h> 27 28 #define DRV_VERSION "0.2" 29 30 #define RS5C348_REG_SECS 0 31 #define RS5C348_REG_MINS 1 32 #define RS5C348_REG_HOURS 2 33 #define RS5C348_REG_WDAY 3 34 #define RS5C348_REG_DAY 4 35 #define RS5C348_REG_MONTH 5 36 #define RS5C348_REG_YEAR 6 37 #define RS5C348_REG_CTL1 14 38 #define RS5C348_REG_CTL2 15 39 40 #define RS5C348_SECS_MASK 0x7f 41 #define RS5C348_MINS_MASK 0x7f 42 #define RS5C348_HOURS_MASK 0x3f 43 #define RS5C348_WDAY_MASK 0x03 44 #define RS5C348_DAY_MASK 0x3f 45 #define RS5C348_MONTH_MASK 0x1f 46 47 #define RS5C348_BIT_PM 0x20 /* REG_HOURS */ 48 #define RS5C348_BIT_Y2K 0x80 /* REG_MONTH */ 49 #define RS5C348_BIT_24H 0x20 /* REG_CTL1 */ 50 #define RS5C348_BIT_XSTP 0x10 /* REG_CTL2 */ 51 #define RS5C348_BIT_VDET 0x40 /* REG_CTL2 */ 52 53 #define RS5C348_CMD_W(addr) (((addr) << 4) | 0x08) /* single write */ 54 #define RS5C348_CMD_R(addr) (((addr) << 4) | 0x0c) /* single read */ 55 #define RS5C348_CMD_MW(addr) (((addr) << 4) | 0x00) /* burst write */ 56 #define RS5C348_CMD_MR(addr) (((addr) << 4) | 0x04) /* burst read */ 57 58 struct rs5c348_plat_data { 59 struct rtc_device *rtc; 60 int rtc_24h; 61 }; 62 63 static int 64 rs5c348_rtc_set_time(struct device *dev, struct rtc_time *tm) 65 { 66 struct spi_device *spi = to_spi_device(dev); 67 struct rs5c348_plat_data *pdata = dev_get_platdata(&spi->dev); 68 u8 txbuf[5+7], *txp; 69 int ret; 70 71 /* Transfer 5 bytes before writing SEC. This gives 31us for carry. */ 72 txp = txbuf; 73 txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */ 74 txbuf[1] = 0; /* dummy */ 75 txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */ 76 txbuf[3] = 0; /* dummy */ 77 txbuf[4] = RS5C348_CMD_MW(RS5C348_REG_SECS); /* cmd, sec, ... */ 78 txp = &txbuf[5]; 79 txp[RS5C348_REG_SECS] = bin2bcd(tm->tm_sec); 80 txp[RS5C348_REG_MINS] = bin2bcd(tm->tm_min); 81 if (pdata->rtc_24h) { 82 txp[RS5C348_REG_HOURS] = bin2bcd(tm->tm_hour); 83 } else { 84 /* hour 0 is AM12, noon is PM12 */ 85 txp[RS5C348_REG_HOURS] = bin2bcd((tm->tm_hour + 11) % 12 + 1) | 86 (tm->tm_hour >= 12 ? RS5C348_BIT_PM : 0); 87 } 88 txp[RS5C348_REG_WDAY] = bin2bcd(tm->tm_wday); 89 txp[RS5C348_REG_DAY] = bin2bcd(tm->tm_mday); 90 txp[RS5C348_REG_MONTH] = bin2bcd(tm->tm_mon + 1) | 91 (tm->tm_year >= 100 ? RS5C348_BIT_Y2K : 0); 92 txp[RS5C348_REG_YEAR] = bin2bcd(tm->tm_year % 100); 93 /* write in one transfer to avoid data inconsistency */ 94 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), NULL, 0); 95 udelay(62); /* Tcsr 62us */ 96 return ret; 97 } 98 99 static int 100 rs5c348_rtc_read_time(struct device *dev, struct rtc_time *tm) 101 { 102 struct spi_device *spi = to_spi_device(dev); 103 struct rs5c348_plat_data *pdata = dev_get_platdata(&spi->dev); 104 u8 txbuf[5], rxbuf[7]; 105 int ret; 106 107 /* Transfer 5 byte befores reading SEC. This gives 31us for carry. */ 108 txbuf[0] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */ 109 txbuf[1] = 0; /* dummy */ 110 txbuf[2] = RS5C348_CMD_R(RS5C348_REG_CTL2); /* cmd, ctl2 */ 111 txbuf[3] = 0; /* dummy */ 112 txbuf[4] = RS5C348_CMD_MR(RS5C348_REG_SECS); /* cmd, sec, ... */ 113 114 /* read in one transfer to avoid data inconsistency */ 115 ret = spi_write_then_read(spi, txbuf, sizeof(txbuf), 116 rxbuf, sizeof(rxbuf)); 117 udelay(62); /* Tcsr 62us */ 118 if (ret < 0) 119 return ret; 120 121 tm->tm_sec = bcd2bin(rxbuf[RS5C348_REG_SECS] & RS5C348_SECS_MASK); 122 tm->tm_min = bcd2bin(rxbuf[RS5C348_REG_MINS] & RS5C348_MINS_MASK); 123 tm->tm_hour = bcd2bin(rxbuf[RS5C348_REG_HOURS] & RS5C348_HOURS_MASK); 124 if (!pdata->rtc_24h) { 125 if (rxbuf[RS5C348_REG_HOURS] & RS5C348_BIT_PM) { 126 tm->tm_hour -= 20; 127 tm->tm_hour %= 12; 128 tm->tm_hour += 12; 129 } else 130 tm->tm_hour %= 12; 131 } 132 tm->tm_wday = bcd2bin(rxbuf[RS5C348_REG_WDAY] & RS5C348_WDAY_MASK); 133 tm->tm_mday = bcd2bin(rxbuf[RS5C348_REG_DAY] & RS5C348_DAY_MASK); 134 tm->tm_mon = 135 bcd2bin(rxbuf[RS5C348_REG_MONTH] & RS5C348_MONTH_MASK) - 1; 136 /* year is 1900 + tm->tm_year */ 137 tm->tm_year = bcd2bin(rxbuf[RS5C348_REG_YEAR]) + 138 ((rxbuf[RS5C348_REG_MONTH] & RS5C348_BIT_Y2K) ? 100 : 0); 139 140 if (rtc_valid_tm(tm) < 0) { 141 dev_err(&spi->dev, "retrieved date/time is not valid.\n"); 142 rtc_time_to_tm(0, tm); 143 } 144 145 return 0; 146 } 147 148 static const struct rtc_class_ops rs5c348_rtc_ops = { 149 .read_time = rs5c348_rtc_read_time, 150 .set_time = rs5c348_rtc_set_time, 151 }; 152 153 static struct spi_driver rs5c348_driver; 154 155 static int rs5c348_probe(struct spi_device *spi) 156 { 157 int ret; 158 struct rtc_device *rtc; 159 struct rs5c348_plat_data *pdata; 160 161 pdata = devm_kzalloc(&spi->dev, sizeof(struct rs5c348_plat_data), 162 GFP_KERNEL); 163 if (!pdata) 164 return -ENOMEM; 165 spi->dev.platform_data = pdata; 166 167 /* Check D7 of SECOND register */ 168 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_SECS)); 169 if (ret < 0 || (ret & 0x80)) { 170 dev_err(&spi->dev, "not found.\n"); 171 goto kfree_exit; 172 } 173 174 dev_info(&spi->dev, "chip found, driver version " DRV_VERSION "\n"); 175 dev_info(&spi->dev, "spiclk %u KHz.\n", 176 (spi->max_speed_hz + 500) / 1000); 177 178 /* turn RTC on if it was not on */ 179 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL2)); 180 if (ret < 0) 181 goto kfree_exit; 182 if (ret & (RS5C348_BIT_XSTP | RS5C348_BIT_VDET)) { 183 u8 buf[2]; 184 struct rtc_time tm; 185 if (ret & RS5C348_BIT_VDET) 186 dev_warn(&spi->dev, "voltage-low detected.\n"); 187 if (ret & RS5C348_BIT_XSTP) 188 dev_warn(&spi->dev, "oscillator-stop detected.\n"); 189 rtc_time_to_tm(0, &tm); /* 1970/1/1 */ 190 ret = rs5c348_rtc_set_time(&spi->dev, &tm); 191 if (ret < 0) 192 goto kfree_exit; 193 buf[0] = RS5C348_CMD_W(RS5C348_REG_CTL2); 194 buf[1] = 0; 195 ret = spi_write_then_read(spi, buf, sizeof(buf), NULL, 0); 196 if (ret < 0) 197 goto kfree_exit; 198 } 199 200 ret = spi_w8r8(spi, RS5C348_CMD_R(RS5C348_REG_CTL1)); 201 if (ret < 0) 202 goto kfree_exit; 203 if (ret & RS5C348_BIT_24H) 204 pdata->rtc_24h = 1; 205 206 rtc = devm_rtc_device_register(&spi->dev, rs5c348_driver.driver.name, 207 &rs5c348_rtc_ops, THIS_MODULE); 208 209 if (IS_ERR(rtc)) { 210 ret = PTR_ERR(rtc); 211 goto kfree_exit; 212 } 213 214 pdata->rtc = rtc; 215 216 return 0; 217 kfree_exit: 218 return ret; 219 } 220 221 static struct spi_driver rs5c348_driver = { 222 .driver = { 223 .name = "rtc-rs5c348", 224 .owner = THIS_MODULE, 225 }, 226 .probe = rs5c348_probe, 227 }; 228 229 module_spi_driver(rs5c348_driver); 230 231 MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); 232 MODULE_DESCRIPTION("Ricoh RS5C348 RTC driver"); 233 MODULE_LICENSE("GPL"); 234 MODULE_VERSION(DRV_VERSION); 235 MODULE_ALIAS("spi:rtc-rs5c348"); 236