133 lines
3.2 KiB
C
133 lines
3.2 KiB
C
/*
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* MAXIM DS1338 I2C RTC+NVRAM
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*
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* Copyright (c) 2009 CodeSourcery.
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* Written by Paul Brook
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*
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* This code is licensed under the GNU GPL v2.
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*/
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#include "i2c.h"
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typedef struct {
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i2c_slave i2c;
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time_t offset;
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struct tm now;
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uint8_t nvram[56];
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int ptr;
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int addr_byte;
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} DS1338State;
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static void ds1338_event(i2c_slave *i2c, enum i2c_event event)
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{
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DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
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switch (event) {
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case I2C_START_RECV:
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qemu_get_timedate(&s->now, s->offset);
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s->nvram[0] = to_bcd(s->now.tm_sec);
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s->nvram[1] = to_bcd(s->now.tm_min);
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if (s->nvram[2] & 0x40) {
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s->nvram[2] = (to_bcd((s->now.tm_hour % 12)) + 1) | 0x40;
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if (s->now.tm_hour >= 12) {
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s->nvram[2] |= 0x20;
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}
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} else {
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s->nvram[2] = to_bcd(s->now.tm_hour);
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}
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s->nvram[3] = to_bcd(s->now.tm_wday) + 1;
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s->nvram[4] = to_bcd(s->now.tm_mday);
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s->nvram[5] = to_bcd(s->now.tm_mon) + 1;
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s->nvram[6] = to_bcd(s->now.tm_year - 100);
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break;
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case I2C_START_SEND:
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s->addr_byte = 1;
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break;
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default:
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break;
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}
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}
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static int ds1338_recv(i2c_slave *i2c)
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{
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DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
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uint8_t res;
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res = s->nvram[s->ptr];
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s->ptr = (s->ptr + 1) & 0xff;
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return res;
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}
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static int ds1338_send(i2c_slave *i2c, uint8_t data)
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{
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DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
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if (s->addr_byte) {
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s->ptr = data;
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s->addr_byte = 0;
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return 0;
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}
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s->nvram[s->ptr - 8] = data;
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if (data < 8) {
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qemu_get_timedate(&s->now, s->offset);
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switch(data) {
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case 0:
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/* TODO: Implement CH (stop) bit. */
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s->now.tm_sec = from_bcd(data & 0x7f);
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break;
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case 1:
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s->now.tm_min = from_bcd(data & 0x7f);
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break;
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case 2:
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if (data & 0x40) {
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if (data & 0x20) {
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data = from_bcd(data & 0x4f) + 11;
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} else {
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data = from_bcd(data & 0x1f) - 1;
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}
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} else {
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data = from_bcd(data);
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}
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s->now.tm_hour = data;
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break;
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case 3:
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s->now.tm_wday = from_bcd(data & 7) - 1;
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break;
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case 4:
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s->now.tm_mday = from_bcd(data & 0x3f);
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break;
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case 5:
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s->now.tm_mon = from_bcd(data & 0x1f) - 1;
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case 6:
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s->now.tm_year = from_bcd(data) + 100;
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break;
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case 7:
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/* Control register. Currently ignored. */
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break;
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}
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s->offset = qemu_timedate_diff(&s->now);
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}
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s->ptr = (s->ptr + 1) & 0xff;
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return 0;
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}
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static int ds1338_init(i2c_slave *i2c)
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{
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return 0;
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}
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static I2CSlaveInfo ds1338_info = {
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.qdev.name = "ds1338",
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.qdev.size = sizeof(DS1338State),
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.init = ds1338_init,
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.event = ds1338_event,
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.recv = ds1338_recv,
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.send = ds1338_send,
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};
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static void ds1338_register_devices(void)
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{
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i2c_register_slave(&ds1338_info);
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}
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device_init(ds1338_register_devices)
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