Uwe Zeisberger | f30c226 | 2006-10-03 23:01:26 +0200 | [diff] [blame] | 1 | /* drivers/rtc/rtc-max6902.c |
Raphael Assenat | 8e12ecc | 2006-06-25 05:48:23 -0700 | [diff] [blame] | 2 | * |
| 3 | * Copyright (C) 2006 8D Technologies inc. |
| 4 | * Copyright (C) 2004 Compulab Ltd. |
| 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 | * Driver for MAX6902 spi RTC |
| 11 | * |
| 12 | * Changelog: |
| 13 | * |
| 14 | * 24-May-2006: Raphael Assenat <raph@8d.com> |
| 15 | * - Major rework |
David Brownell | 5c076fc | 2007-08-22 14:01:57 -0700 | [diff] [blame] | 16 | * Converted to rtc_device and uses the SPI layer. |
Raphael Assenat | 8e12ecc | 2006-06-25 05:48:23 -0700 | [diff] [blame] | 17 | * |
| 18 | * ??-???-2005: Someone at Compulab |
| 19 | * - Initial driver creation. |
| 20 | */ |
| 21 | |
Raphael Assenat | 8e12ecc | 2006-06-25 05:48:23 -0700 | [diff] [blame] | 22 | #include <linux/module.h> |
| 23 | #include <linux/version.h> |
| 24 | |
| 25 | #include <linux/kernel.h> |
| 26 | #include <linux/platform_device.h> |
| 27 | #include <linux/init.h> |
| 28 | #include <linux/rtc.h> |
| 29 | #include <linux/spi/spi.h> |
| 30 | #include <linux/bcd.h> |
| 31 | #include <linux/delay.h> |
| 32 | |
| 33 | #define MAX6902_REG_SECONDS 0x01 |
| 34 | #define MAX6902_REG_MINUTES 0x03 |
| 35 | #define MAX6902_REG_HOURS 0x05 |
| 36 | #define MAX6902_REG_DATE 0x07 |
| 37 | #define MAX6902_REG_MONTH 0x09 |
| 38 | #define MAX6902_REG_DAY 0x0B |
| 39 | #define MAX6902_REG_YEAR 0x0D |
| 40 | #define MAX6902_REG_CONTROL 0x0F |
| 41 | #define MAX6902_REG_CENTURY 0x13 |
| 42 | |
| 43 | #undef MAX6902_DEBUG |
| 44 | |
| 45 | struct max6902 { |
| 46 | struct rtc_device *rtc; |
| 47 | u8 buf[9]; /* Burst read cmd + 8 registers */ |
| 48 | u8 tx_buf[2]; |
| 49 | u8 rx_buf[2]; |
| 50 | }; |
| 51 | |
| 52 | static void max6902_set_reg(struct device *dev, unsigned char address, |
| 53 | unsigned char data) |
| 54 | { |
| 55 | struct spi_device *spi = to_spi_device(dev); |
| 56 | unsigned char buf[2]; |
| 57 | |
| 58 | /* MSB must be '0' to write */ |
| 59 | buf[0] = address & 0x7f; |
| 60 | buf[1] = data; |
| 61 | |
| 62 | spi_write(spi, buf, 2); |
| 63 | } |
| 64 | |
| 65 | static int max6902_get_reg(struct device *dev, unsigned char address, |
| 66 | unsigned char *data) |
| 67 | { |
| 68 | struct spi_device *spi = to_spi_device(dev); |
| 69 | struct max6902 *chip = dev_get_drvdata(dev); |
| 70 | struct spi_message message; |
| 71 | struct spi_transfer xfer; |
| 72 | int status; |
| 73 | |
| 74 | if (!data) |
| 75 | return -EINVAL; |
| 76 | |
| 77 | /* Build our spi message */ |
| 78 | spi_message_init(&message); |
| 79 | memset(&xfer, 0, sizeof(xfer)); |
| 80 | xfer.len = 2; |
| 81 | /* Can tx_buf and rx_buf be equal? The doc in spi.h is not sure... */ |
| 82 | xfer.tx_buf = chip->tx_buf; |
| 83 | xfer.rx_buf = chip->rx_buf; |
| 84 | |
| 85 | /* Set MSB to indicate read */ |
| 86 | chip->tx_buf[0] = address | 0x80; |
| 87 | |
| 88 | spi_message_add_tail(&xfer, &message); |
| 89 | |
| 90 | /* do the i/o */ |
| 91 | status = spi_sync(spi, &message); |
| 92 | if (status == 0) |
| 93 | status = message.status; |
| 94 | else |
| 95 | return status; |
| 96 | |
| 97 | *data = chip->rx_buf[1]; |
| 98 | |
| 99 | return status; |
| 100 | } |
| 101 | |
| 102 | static int max6902_get_datetime(struct device *dev, struct rtc_time *dt) |
| 103 | { |
| 104 | unsigned char tmp; |
| 105 | int century; |
| 106 | int err; |
| 107 | struct spi_device *spi = to_spi_device(dev); |
| 108 | struct max6902 *chip = dev_get_drvdata(dev); |
| 109 | struct spi_message message; |
| 110 | struct spi_transfer xfer; |
| 111 | int status; |
| 112 | |
| 113 | err = max6902_get_reg(dev, MAX6902_REG_CENTURY, &tmp); |
| 114 | if (err) |
| 115 | return err; |
| 116 | |
| 117 | /* build the message */ |
| 118 | spi_message_init(&message); |
| 119 | memset(&xfer, 0, sizeof(xfer)); |
| 120 | xfer.len = 1 + 7; /* Burst read command + 7 registers */ |
| 121 | xfer.tx_buf = chip->buf; |
| 122 | xfer.rx_buf = chip->buf; |
| 123 | chip->buf[0] = 0xbf; /* Burst read */ |
| 124 | spi_message_add_tail(&xfer, &message); |
| 125 | |
| 126 | /* do the i/o */ |
| 127 | status = spi_sync(spi, &message); |
| 128 | if (status == 0) |
| 129 | status = message.status; |
| 130 | else |
| 131 | return status; |
| 132 | |
| 133 | /* The chip sends data in this order: |
| 134 | * Seconds, Minutes, Hours, Date, Month, Day, Year */ |
| 135 | dt->tm_sec = BCD2BIN(chip->buf[1]); |
| 136 | dt->tm_min = BCD2BIN(chip->buf[2]); |
| 137 | dt->tm_hour = BCD2BIN(chip->buf[3]); |
| 138 | dt->tm_mday = BCD2BIN(chip->buf[4]); |
Francisco Larramendi | c430169 | 2006-10-17 00:09:53 -0700 | [diff] [blame] | 139 | dt->tm_mon = BCD2BIN(chip->buf[5]) - 1; |
Raphael Assenat | 8e12ecc | 2006-06-25 05:48:23 -0700 | [diff] [blame] | 140 | dt->tm_wday = BCD2BIN(chip->buf[6]); |
| 141 | dt->tm_year = BCD2BIN(chip->buf[7]); |
| 142 | |
| 143 | century = BCD2BIN(tmp) * 100; |
| 144 | |
| 145 | dt->tm_year += century; |
| 146 | dt->tm_year -= 1900; |
| 147 | |
| 148 | #ifdef MAX6902_DEBUG |
| 149 | printk("\n%s : Read RTC values\n",__FUNCTION__); |
| 150 | printk("tm_hour: %i\n",dt->tm_hour); |
| 151 | printk("tm_min : %i\n",dt->tm_min); |
| 152 | printk("tm_sec : %i\n",dt->tm_sec); |
| 153 | printk("tm_year: %i\n",dt->tm_year); |
| 154 | printk("tm_mon : %i\n",dt->tm_mon); |
| 155 | printk("tm_mday: %i\n",dt->tm_mday); |
| 156 | printk("tm_wday: %i\n",dt->tm_wday); |
| 157 | #endif |
| 158 | |
| 159 | return 0; |
| 160 | } |
| 161 | |
| 162 | static int max6902_set_datetime(struct device *dev, struct rtc_time *dt) |
| 163 | { |
| 164 | dt->tm_year = dt->tm_year+1900; |
| 165 | |
| 166 | #ifdef MAX6902_DEBUG |
| 167 | printk("\n%s : Setting RTC values\n",__FUNCTION__); |
| 168 | printk("tm_sec : %i\n",dt->tm_sec); |
| 169 | printk("tm_min : %i\n",dt->tm_min); |
| 170 | printk("tm_hour: %i\n",dt->tm_hour); |
| 171 | printk("tm_mday: %i\n",dt->tm_mday); |
| 172 | printk("tm_wday: %i\n",dt->tm_wday); |
| 173 | printk("tm_year: %i\n",dt->tm_year); |
| 174 | #endif |
| 175 | |
| 176 | /* Remove write protection */ |
| 177 | max6902_set_reg(dev, 0xF, 0); |
| 178 | |
| 179 | max6902_set_reg(dev, 0x01, BIN2BCD(dt->tm_sec)); |
| 180 | max6902_set_reg(dev, 0x03, BIN2BCD(dt->tm_min)); |
| 181 | max6902_set_reg(dev, 0x05, BIN2BCD(dt->tm_hour)); |
| 182 | |
| 183 | max6902_set_reg(dev, 0x07, BIN2BCD(dt->tm_mday)); |
| 184 | max6902_set_reg(dev, 0x09, BIN2BCD(dt->tm_mon+1)); |
| 185 | max6902_set_reg(dev, 0x0B, BIN2BCD(dt->tm_wday)); |
| 186 | max6902_set_reg(dev, 0x0D, BIN2BCD(dt->tm_year%100)); |
| 187 | max6902_set_reg(dev, 0x13, BIN2BCD(dt->tm_year/100)); |
| 188 | |
| 189 | /* Compulab used a delay here. However, the datasheet |
| 190 | * does not mention a delay being required anywhere... */ |
| 191 | /* delay(2000); */ |
| 192 | |
| 193 | /* Write protect */ |
| 194 | max6902_set_reg(dev, 0xF, 0x80); |
| 195 | |
| 196 | return 0; |
| 197 | } |
| 198 | |
| 199 | static int max6902_read_time(struct device *dev, struct rtc_time *tm) |
| 200 | { |
| 201 | return max6902_get_datetime(dev, tm); |
| 202 | } |
| 203 | |
| 204 | static int max6902_set_time(struct device *dev, struct rtc_time *tm) |
| 205 | { |
| 206 | return max6902_set_datetime(dev, tm); |
| 207 | } |
| 208 | |
David Brownell | ff8371a | 2006-09-30 23:28:17 -0700 | [diff] [blame] | 209 | static const struct rtc_class_ops max6902_rtc_ops = { |
Raphael Assenat | 8e12ecc | 2006-06-25 05:48:23 -0700 | [diff] [blame] | 210 | .read_time = max6902_read_time, |
| 211 | .set_time = max6902_set_time, |
| 212 | }; |
| 213 | |
| 214 | static int __devinit max6902_probe(struct spi_device *spi) |
| 215 | { |
| 216 | struct rtc_device *rtc; |
| 217 | unsigned char tmp; |
| 218 | struct max6902 *chip; |
| 219 | int res; |
| 220 | |
| 221 | rtc = rtc_device_register("max6902", |
| 222 | &spi->dev, &max6902_rtc_ops, THIS_MODULE); |
| 223 | if (IS_ERR(rtc)) |
| 224 | return PTR_ERR(rtc); |
| 225 | |
| 226 | spi->mode = SPI_MODE_3; |
| 227 | spi->bits_per_word = 8; |
| 228 | spi_setup(spi); |
| 229 | |
| 230 | chip = kzalloc(sizeof *chip, GFP_KERNEL); |
| 231 | if (!chip) { |
| 232 | rtc_device_unregister(rtc); |
| 233 | return -ENOMEM; |
| 234 | } |
| 235 | chip->rtc = rtc; |
| 236 | dev_set_drvdata(&spi->dev, chip); |
| 237 | |
| 238 | res = max6902_get_reg(&spi->dev, MAX6902_REG_SECONDS, &tmp); |
| 239 | if (res) { |
| 240 | rtc_device_unregister(rtc); |
| 241 | return res; |
| 242 | } |
| 243 | |
| 244 | return 0; |
| 245 | } |
| 246 | |
| 247 | static int __devexit max6902_remove(struct spi_device *spi) |
| 248 | { |
| 249 | struct max6902 *chip = platform_get_drvdata(spi); |
| 250 | struct rtc_device *rtc = chip->rtc; |
| 251 | |
| 252 | if (rtc) |
| 253 | rtc_device_unregister(rtc); |
| 254 | |
| 255 | kfree(chip); |
| 256 | |
| 257 | return 0; |
| 258 | } |
| 259 | |
| 260 | static struct spi_driver max6902_driver = { |
| 261 | .driver = { |
David Brownell | 5c076fc | 2007-08-22 14:01:57 -0700 | [diff] [blame] | 262 | .name = "rtc-max6902", |
Raphael Assenat | 8e12ecc | 2006-06-25 05:48:23 -0700 | [diff] [blame] | 263 | .bus = &spi_bus_type, |
| 264 | .owner = THIS_MODULE, |
| 265 | }, |
David Brownell | 5c076fc | 2007-08-22 14:01:57 -0700 | [diff] [blame] | 266 | .probe = max6902_probe, |
Raphael Assenat | 8e12ecc | 2006-06-25 05:48:23 -0700 | [diff] [blame] | 267 | .remove = __devexit_p(max6902_remove), |
| 268 | }; |
| 269 | |
| 270 | static __init int max6902_init(void) |
| 271 | { |
| 272 | printk("max6902 spi driver\n"); |
| 273 | return spi_register_driver(&max6902_driver); |
| 274 | } |
| 275 | module_init(max6902_init); |
| 276 | |
| 277 | static __exit void max6902_exit(void) |
| 278 | { |
| 279 | spi_unregister_driver(&max6902_driver); |
| 280 | } |
| 281 | module_exit(max6902_exit); |
| 282 | |
| 283 | MODULE_DESCRIPTION ("max6902 spi RTC driver"); |
| 284 | MODULE_AUTHOR ("Raphael Assenat"); |
| 285 | MODULE_LICENSE ("GPL"); |