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/*
* Constant and architecture independent procedures
* for NEC uPD4990A serial I/O real-time clock.
*
* Copyright 2001 TAKAI Kousuke <tak@kmc.kyoto-u.ac.jp>
* Kyoto University Microcomputer Club (KMC).
*
* References:
* uPD4990A serial I/O real-time clock users' manual (Japanese)
* No. S12828JJ4V0UM00 (4th revision), NEC Corporation, 1999.
*/
#ifndef _LINUX_uPD4990A_H
#define _LINUX_uPD4990A_H
#include <asm/byteorder.h>
#include <asm/upd4990a.h>
/* Serial commands (4 bits) */
#define UPD4990A_REGISTER_HOLD (0x0)
#define UPD4990A_REGISTER_SHIFT (0x1)
#define UPD4990A_TIME_SET_AND_COUNTER_HOLD (0x2)
#define UPD4990A_TIME_READ (0x3)
#define UPD4990A_TP_64HZ (0x4)
#define UPD4990A_TP_256HZ (0x5)
#define UPD4990A_TP_2048HZ (0x6)
#define UPD4990A_TP_4096HZ (0x7)
#define UPD4990A_TP_1S (0x8)
#define UPD4990A_TP_10S (0x9)
#define UPD4990A_TP_30S (0xA)
#define UPD4990A_TP_60S (0xB)
#define UPD4990A_INTERRUPT_RESET (0xC)
#define UPD4990A_INTERRUPT_TIMER_START (0xD)
#define UPD4990A_INTERRUPT_TIMER_STOP (0xE)
#define UPD4990A_TEST_MODE_SET (0xF)
/* Parallel commands (3 bits)
0-6 are same with serial commands. */
#define UPD4990A_PAR_SERIAL_MODE 7
#ifndef UPD4990A_DELAY
# include <linux/delay.h>
# define UPD4990A_DELAY(usec) udelay((usec))
#endif
#ifndef UPD4990A_OUTPUT_DATA
# define UPD4990A_OUTPUT_DATA(bit) \
do { \
UPD4990A_OUTPUT_DATA_CLK((bit), 0); \
UPD4990A_DELAY(1); /* t-DSU */ \
UPD4990A_OUTPUT_DATA_CLK((bit), 1); \
UPD4990A_DELAY(1); /* t-DHLD */ \
} while (0)
#endif
static __inline__ void upd4990a_serial_command(int command)
{
UPD4990A_OUTPUT_DATA(command >> 0);
UPD4990A_OUTPUT_DATA(command >> 1);
UPD4990A_OUTPUT_DATA(command >> 2);
UPD4990A_OUTPUT_DATA(command >> 3);
UPD4990A_DELAY(1); /* t-HLD */
UPD4990A_OUTPUT_STROBE(1);
UPD4990A_DELAY(1); /* t-STB & t-d1 */
UPD4990A_OUTPUT_STROBE(0);
/* 19 microseconds extra delay is needed
iff previous mode is TIME READ command */
}
struct upd4990a_raw_data {
u8 sec; /* BCD */
u8 min; /* BCD */
u8 hour; /* BCD */
u8 mday; /* BCD */
#if defined __LITTLE_ENDIAN_BITFIELD
unsigned wday :4; /* 0-6 */
unsigned mon :4; /* 1-based */
#elif defined __BIG_ENDIAN_BITFIELD
unsigned mon :4; /* 1-based */
unsigned wday :4; /* 0-6 */
#else
# error Unknown bitfield endian!
#endif
u8 year; /* BCD */
};
static __inline__ void upd4990a_get_time(struct upd4990a_raw_data *buf,
int leave_register_hold)
{
int byte;
upd4990a_serial_command(UPD4990A_TIME_READ);
upd4990a_serial_command(UPD4990A_REGISTER_SHIFT);
UPD4990A_DELAY(19); /* t-d2 - t-d1 */
for (byte = 0; byte < 6; byte++) {
u8 tmp;
int bit;
for (tmp = 0, bit = 0; bit < 8; bit++) {
tmp = (tmp | (UPD4990A_READ_DATA() << 8)) >> 1;
UPD4990A_OUTPUT_CLK(1);
UPD4990A_DELAY(1);
UPD4990A_OUTPUT_CLK(0);
UPD4990A_DELAY(1);
}
((u8 *) buf)[byte] = tmp;
}
/* The uPD4990A users' manual says that we should issue `Register
Hold' command after each data retrieval, or next `Time Read'
command may not work correctly. */
if (!leave_register_hold)
upd4990a_serial_command(UPD4990A_REGISTER_HOLD);
}
static __inline__ void upd4990a_set_time(const struct upd4990a_raw_data *data,
int time_set_only)
{
int byte;
if (!time_set_only)
upd4990a_serial_command(UPD4990A_REGISTER_SHIFT);
for (byte = 0; byte < 6; byte++) {
int bit;
u8 tmp = ((const u8 *) data)[byte];
for (bit = 0; bit < 8; bit++, tmp >>= 1)
UPD4990A_OUTPUT_DATA(tmp);
}
upd4990a_serial_command(UPD4990A_TIME_SET_AND_COUNTER_HOLD);
/* Release counter hold and start the clock. */
if (!time_set_only)
upd4990a_serial_command(UPD4990A_REGISTER_HOLD);
}
#endif /* _LINUX_uPD4990A_H */
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