max6900.c 2.5 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * (C) Copyright 2004
  4. * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
  5. */
  6. /*
  7. * Date & Time support for MAXIM MAX6900 RTC
  8. */
  9. /* #define DEBUG */
  10. #include <common.h>
  11. #include <command.h>
  12. #include <rtc.h>
  13. #include <i2c.h>
  14. #include <linux/delay.h>
  15. #ifndef CONFIG_SYS_I2C_RTC_ADDR
  16. #define CONFIG_SYS_I2C_RTC_ADDR 0x50
  17. #endif
  18. /* ------------------------------------------------------------------------- */
  19. static uchar rtc_read (uchar reg)
  20. {
  21. return (i2c_reg_read (CONFIG_SYS_I2C_RTC_ADDR, reg));
  22. }
  23. static void rtc_write (uchar reg, uchar val)
  24. {
  25. i2c_reg_write (CONFIG_SYS_I2C_RTC_ADDR, reg, val);
  26. udelay(2500);
  27. }
  28. /* ------------------------------------------------------------------------- */
  29. int rtc_get (struct rtc_time *tmp)
  30. {
  31. uchar sec, min, hour, mday, wday, mon, cent, year;
  32. int retry = 1;
  33. do {
  34. sec = rtc_read (0x80);
  35. min = rtc_read (0x82);
  36. hour = rtc_read (0x84);
  37. mday = rtc_read (0x86);
  38. mon = rtc_read (0x88);
  39. wday = rtc_read (0x8a);
  40. year = rtc_read (0x8c);
  41. cent = rtc_read (0x92);
  42. /*
  43. * Check for seconds rollover
  44. */
  45. if ((sec != 59) || (rtc_read(0x80) == sec)){
  46. retry = 0;
  47. }
  48. } while (retry);
  49. debug ( "Get RTC year: %02x mon: %02x cent: %02x mday: %02x wday: %02x "
  50. "hr: %02x min: %02x sec: %02x\n",
  51. year, mon, cent, mday, wday,
  52. hour, min, sec );
  53. tmp->tm_sec = bcd2bin (sec & 0x7F);
  54. tmp->tm_min = bcd2bin (min & 0x7F);
  55. tmp->tm_hour = bcd2bin (hour & 0x3F);
  56. tmp->tm_mday = bcd2bin (mday & 0x3F);
  57. tmp->tm_mon = bcd2bin (mon & 0x1F);
  58. tmp->tm_year = bcd2bin (year) + bcd2bin(cent) * 100;
  59. tmp->tm_wday = bcd2bin (wday & 0x07);
  60. tmp->tm_yday = 0;
  61. tmp->tm_isdst= 0;
  62. debug ( "Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
  63. tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  64. tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  65. return 0;
  66. }
  67. int rtc_set (struct rtc_time *tmp)
  68. {
  69. debug ( "Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n",
  70. tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
  71. tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
  72. rtc_write (0x9E, 0x00);
  73. rtc_write (0x80, 0); /* Clear seconds to ensure no rollover */
  74. rtc_write (0x92, bin2bcd(tmp->tm_year / 100));
  75. rtc_write (0x8c, bin2bcd(tmp->tm_year % 100));
  76. rtc_write (0x8a, bin2bcd(tmp->tm_wday));
  77. rtc_write (0x88, bin2bcd(tmp->tm_mon));
  78. rtc_write (0x86, bin2bcd(tmp->tm_mday));
  79. rtc_write (0x84, bin2bcd(tmp->tm_hour));
  80. rtc_write (0x82, bin2bcd(tmp->tm_min ));
  81. rtc_write (0x80, bin2bcd(tmp->tm_sec ));
  82. return 0;
  83. }
  84. void rtc_reset (void)
  85. {
  86. }