2 * Architecture dependent definitions
3 * for NEC uPD4990A serial I/O real-time clock.
5 * Copyright 2001 TAKAI Kousuke <tak@kmc.kyoto-u.ac.jp>
6 * Kyoto University Microcomputer Club (KMC).
9 * uPD4990A serial I/O real-time clock users' manual (Japanese)
10 * No. S12828JJ4V0UM00 (4th revision), NEC Corporation, 1999.
13 #ifndef _ASM_I386_uPD4990A_H
14 #define _ASM_I386_uPD4990A_H
18 #define UPD4990A_IO (0x0020)
19 #define UPD4990A_IO_DATAOUT (0x0033)
21 #define UPD4990A_OUTPUT_DATA_CLK(data, clk) \
22 outb((((data) & 1) << 5) | (((clk) & 1) << 4) \
23 | UPD4990A_PAR_SERIAL_MODE, UPD4990A_IO)
25 #define UPD4990A_OUTPUT_CLK(clk) UPD4990A_OUTPUT_DATA_CLK(0, (clk))
27 #define UPD4990A_OUTPUT_STROBE(stb) \
28 outb(((stb) << 3) | UPD4990A_PAR_SERIAL_MODE, UPD4990A_IO)
31 * Note: udelay() is *not* usable for UPD4990A_DELAY because
32 * the Linux kernel reads uPD4990A to set up system clock
33 * before calibrating delay...
35 #define UPD4990A_DELAY(usec) \
37 if (__builtin_constant_p((usec)) && (usec) < 5) \
38 __asm__ (".rept %c1\n\toutb %%al,%0\n\t.endr" \
40 "i" (((usec) * 10 + 5) / 6)); \
42 int _count = ((usec) * 10 + 5) / 6; \
43 __asm__ volatile ("1: outb %%al,%1\n\tloop 1b" \
45 : "N" (0x5F), "0" (_count)); \
49 /* Caller should ignore all bits except bit0 */
50 #define UPD4990A_READ_DATA() inb(UPD4990A_IO_DATAOUT)