| 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 = spi->dev.platform_data; |
| 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 = spi->dev.platform_data; |
| 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 int rs5c348_remove(struct spi_device *spi) |
| 222 | { |
| 223 | return 0; |
| 224 | } |
| 225 | |
| 226 | static struct spi_driver rs5c348_driver = { |
| 227 | .driver = { |
| 228 | .name = "rtc-rs5c348", |
| 229 | .owner = THIS_MODULE, |
| 230 | }, |
| 231 | .probe = rs5c348_probe, |
| 232 | .remove = rs5c348_remove, |
| 233 | }; |
| 234 | |
| 235 | module_spi_driver(rs5c348_driver); |
| 236 | |
| 237 | MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>"); |
| 238 | MODULE_DESCRIPTION("Ricoh RS5C348 RTC driver"); |
| 239 | MODULE_LICENSE("GPL"); |
| 240 | MODULE_VERSION(DRV_VERSION); |
| 241 | MODULE_ALIAS("spi:rtc-rs5c348"); |