203 lines
4.9 KiB
C
203 lines
4.9 KiB
C
/*
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* RTC routines for RICOH Rx5C348 SPI chip.
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* Copyright (C) 2000-2001 Toshiba Corporation
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*
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* 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
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* terms of the GNU General Public License version 2. This program is
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* licensed "as is" without any warranty of any kind, whether express
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* or implied.
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*
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* Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com)
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/rtc.h>
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#include <linux/time.h>
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#include <asm/time.h>
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#include <asm/tx4938/spi.h>
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#define EPOCH 2000
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/* registers */
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#define Rx5C348_REG_SECOND 0
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#define Rx5C348_REG_MINUTE 1
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#define Rx5C348_REG_HOUR 2
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#define Rx5C348_REG_WEEK 3
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#define Rx5C348_REG_DAY 4
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#define Rx5C348_REG_MONTH 5
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#define Rx5C348_REG_YEAR 6
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#define Rx5C348_REG_ADJUST 7
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#define Rx5C348_REG_ALARM_W_MIN 8
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#define Rx5C348_REG_ALARM_W_HOUR 9
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#define Rx5C348_REG_ALARM_W_WEEK 10
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#define Rx5C348_REG_ALARM_D_MIN 11
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#define Rx5C348_REG_ALARM_D_HOUR 12
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#define Rx5C348_REG_CTL1 14
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#define Rx5C348_REG_CTL2 15
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/* register bits */
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#define Rx5C348_BIT_PM 0x20 /* REG_HOUR */
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#define Rx5C348_BIT_Y2K 0x80 /* REG_MONTH */
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#define Rx5C348_BIT_24H 0x20 /* REG_CTL1 */
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#define Rx5C348_BIT_XSTP 0x10 /* REG_CTL2 */
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/* commands */
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#define Rx5C348_CMD_W(addr) (((addr) << 4) | 0x08) /* single write */
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#define Rx5C348_CMD_R(addr) (((addr) << 4) | 0x0c) /* single read */
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#define Rx5C348_CMD_MW(addr) (((addr) << 4) | 0x00) /* burst write */
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#define Rx5C348_CMD_MR(addr) (((addr) << 4) | 0x04) /* burst read */
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static struct spi_dev_desc srtc_dev_desc = {
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.baud = 1000000, /* 1.0Mbps @ Vdd 2.0V */
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.tcss = 31,
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.tcsh = 1,
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.tcsr = 62,
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/* 31us for Tcss (62us for Tcsr) is required for carry operation) */
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.byteorder = 1, /* MSB-First */
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.polarity = 0, /* High-Active */
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.phase = 1, /* Shift-Then-Sample */
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};
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static int srtc_chipid;
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static int srtc_24h;
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static inline int
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spi_rtc_io(unsigned char *inbuf, unsigned char *outbuf, unsigned int count)
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{
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unsigned char *inbufs[1], *outbufs[1];
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unsigned int incounts[2], outcounts[2];
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inbufs[0] = inbuf;
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incounts[0] = count;
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incounts[1] = 0;
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outbufs[0] = outbuf;
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outcounts[0] = count;
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outcounts[1] = 0;
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return txx9_spi_io(srtc_chipid, &srtc_dev_desc,
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inbufs, incounts, outbufs, outcounts, 0);
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}
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/*
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* Conversion between binary and BCD.
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*/
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#ifndef BCD_TO_BIN
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#define BCD_TO_BIN(val) ((val)=((val)&15) + ((val)>>4)*10)
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#endif
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#ifndef BIN_TO_BCD
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#define BIN_TO_BCD(val) ((val)=(((val)/10)<<4) + (val)%10)
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#endif
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/* RTC-dependent code for time.c */
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static int
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rtc_rx5c348_set_time(unsigned long t)
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{
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unsigned char inbuf[8];
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struct rtc_time tm;
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u8 year, month, day, hour, minute, second, century;
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/* convert */
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to_tm(t, &tm);
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year = tm.tm_year % 100;
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month = tm.tm_mon+1; /* tm_mon starts from 0 to 11 */
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day = tm.tm_mday;
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hour = tm.tm_hour;
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minute = tm.tm_min;
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second = tm.tm_sec;
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century = tm.tm_year / 100;
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inbuf[0] = Rx5C348_CMD_MW(Rx5C348_REG_SECOND);
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BIN_TO_BCD(second);
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inbuf[1] = second;
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BIN_TO_BCD(minute);
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inbuf[2] = minute;
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if (srtc_24h) {
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BIN_TO_BCD(hour);
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inbuf[3] = hour;
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} else {
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/* hour 0 is AM12, noon is PM12 */
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inbuf[3] = 0;
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if (hour >= 12)
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inbuf[3] = Rx5C348_BIT_PM;
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hour = (hour + 11) % 12 + 1;
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BIN_TO_BCD(hour);
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inbuf[3] |= hour;
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}
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inbuf[4] = 0; /* ignore week */
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BIN_TO_BCD(day);
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inbuf[5] = day;
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BIN_TO_BCD(month);
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inbuf[6] = month;
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if (century >= 20)
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inbuf[6] |= Rx5C348_BIT_Y2K;
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BIN_TO_BCD(year);
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inbuf[7] = year;
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/* write in one transfer to avoid data inconsistency */
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return spi_rtc_io(inbuf, NULL, 8);
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}
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static unsigned long
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rtc_rx5c348_get_time(void)
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{
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unsigned char inbuf[8], outbuf[8];
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unsigned int year, month, day, hour, minute, second;
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inbuf[0] = Rx5C348_CMD_MR(Rx5C348_REG_SECOND);
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memset(inbuf + 1, 0, 7);
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/* read in one transfer to avoid data inconsistency */
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if (spi_rtc_io(inbuf, outbuf, 8))
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return 0;
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second = outbuf[1];
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BCD_TO_BIN(second);
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minute = outbuf[2];
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BCD_TO_BIN(minute);
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if (srtc_24h) {
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hour = outbuf[3];
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BCD_TO_BIN(hour);
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} else {
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hour = outbuf[3] & ~Rx5C348_BIT_PM;
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BCD_TO_BIN(hour);
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hour %= 12;
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if (outbuf[3] & Rx5C348_BIT_PM)
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hour += 12;
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}
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day = outbuf[5];
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BCD_TO_BIN(day);
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month = outbuf[6] & ~Rx5C348_BIT_Y2K;
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BCD_TO_BIN(month);
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year = outbuf[7];
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BCD_TO_BIN(year);
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year += EPOCH;
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return mktime(year, month, day, hour, minute, second);
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}
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void __init
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rtc_rx5c348_init(int chipid)
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{
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unsigned char inbuf[2], outbuf[2];
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srtc_chipid = chipid;
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/* turn on RTC if it is not on */
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inbuf[0] = Rx5C348_CMD_R(Rx5C348_REG_CTL2);
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inbuf[1] = 0;
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spi_rtc_io(inbuf, outbuf, 2);
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if (outbuf[1] & Rx5C348_BIT_XSTP) {
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inbuf[0] = Rx5C348_CMD_W(Rx5C348_REG_CTL2);
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inbuf[1] = 0;
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spi_rtc_io(inbuf, NULL, 2);
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}
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inbuf[0] = Rx5C348_CMD_R(Rx5C348_REG_CTL1);
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inbuf[1] = 0;
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spi_rtc_io(inbuf, outbuf, 2);
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if (outbuf[1] & Rx5C348_BIT_24H)
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srtc_24h = 1;
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/* set the function pointers */
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rtc_get_time = rtc_rx5c348_get_time;
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rtc_set_time = rtc_rx5c348_set_time;
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}
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