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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2000, 2001 Broadcom Corporation
*
* Copyright (C) 2002 MontaVista Software Inc.
* Author: jsun@mvista.com or jsun@junsun.net
*/
#include <linux/bcd.h>
#include <linux/types.h>
#include <linux/time.h>
#include <asm/time.h>
#include <asm/addrspace.h>
#include <asm/io.h>
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_smbus.h>
/* M41T81 definitions */
/*
* Register bits
*/
#define M41T81REG_SC_ST 0x80 /* stop bit */
#define M41T81REG_HR_CB 0x40 /* century bit */
#define M41T81REG_HR_CEB 0x80 /* century enable bit */
#define M41T81REG_CTL_S 0x20 /* sign bit */
#define M41T81REG_CTL_FT 0x40 /* frequency test bit */
#define M41T81REG_CTL_OUT 0x80 /* output level */
#define M41T81REG_WD_RB0 0x01 /* watchdog resolution bit 0 */
#define M41T81REG_WD_RB1 0x02 /* watchdog resolution bit 1 */
#define M41T81REG_WD_BMB0 0x04 /* watchdog multiplier bit 0 */
#define M41T81REG_WD_BMB1 0x08 /* watchdog multiplier bit 1 */
#define M41T81REG_WD_BMB2 0x10 /* watchdog multiplier bit 2 */
#define M41T81REG_WD_BMB3 0x20 /* watchdog multiplier bit 3 */
#define M41T81REG_WD_BMB4 0x40 /* watchdog multiplier bit 4 */
#define M41T81REG_AMO_ABE 0x20 /* alarm in "battery back-up mode" enable bit */
#define M41T81REG_AMO_SQWE 0x40 /* square wave enable */
#define M41T81REG_AMO_AFE 0x80 /* alarm flag enable flag */
#define M41T81REG_ADT_RPT5 0x40 /* alarm repeat mode bit 5 */
#define M41T81REG_ADT_RPT4 0x80 /* alarm repeat mode bit 4 */
#define M41T81REG_AHR_RPT3 0x80 /* alarm repeat mode bit 3 */
#define M41T81REG_AHR_HT 0x40 /* halt update bit */
#define M41T81REG_AMN_RPT2 0x80 /* alarm repeat mode bit 2 */
#define M41T81REG_ASC_RPT1 0x80 /* alarm repeat mode bit 1 */
#define M41T81REG_FLG_AF 0x40 /* alarm flag (read only) */
#define M41T81REG_FLG_WDF 0x80 /* watchdog flag (read only) */
#define M41T81REG_SQW_RS0 0x10 /* sqw frequency bit 0 */
#define M41T81REG_SQW_RS1 0x20 /* sqw frequency bit 1 */
#define M41T81REG_SQW_RS2 0x40 /* sqw frequency bit 2 */
#define M41T81REG_SQW_RS3 0x80 /* sqw frequency bit 3 */
/*
* Register numbers
*/
#define M41T81REG_TSC 0x00 /* tenths/hundredths of second */
#define M41T81REG_SC 0x01 /* seconds */
#define M41T81REG_MN 0x02 /* minute */
#define M41T81REG_HR 0x03 /* hour/century */
#define M41T81REG_DY 0x04 /* day of week */
#define M41T81REG_DT 0x05 /* date of month */
#define M41T81REG_MO 0x06 /* month */
#define M41T81REG_YR 0x07 /* year */
#define M41T81REG_CTL 0x08 /* control */
#define M41T81REG_WD 0x09 /* watchdog */
#define M41T81REG_AMO 0x0A /* alarm: month */
#define M41T81REG_ADT 0x0B /* alarm: date */
#define M41T81REG_AHR 0x0C /* alarm: hour */
#define M41T81REG_AMN 0x0D /* alarm: minute */
#define M41T81REG_ASC 0x0E /* alarm: second */
#define M41T81REG_FLG 0x0F /* flags */
#define M41T81REG_SQW 0x13 /* square wave register */
#define M41T81_CCR_ADDRESS 0x68
#define SMB_CSR(reg) IOADDR(A_SMB_REGISTER(1, reg))
static int m41t81_read(uint8_t addr)
{
while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
__raw_writeq(addr & 0xff, SMB_CSR(R_SMB_CMD));
__raw_writeq(V_SMB_ADDR(M41T81_CCR_ADDRESS) | V_SMB_TT_WR1BYTE,
SMB_CSR(R_SMB_START));
while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
__raw_writeq(V_SMB_ADDR(M41T81_CCR_ADDRESS) | V_SMB_TT_RD1BYTE,
SMB_CSR(R_SMB_START));
while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
/* Clear error bit by writing a 1 */
__raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
return -1;
}
return __raw_readq(SMB_CSR(R_SMB_DATA)) & 0xff;
}
static int m41t81_write(uint8_t addr, int b)
{
while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
__raw_writeq(addr & 0xff, SMB_CSR(R_SMB_CMD));
__raw_writeq(b & 0xff, SMB_CSR(R_SMB_DATA));
__raw_writeq(V_SMB_ADDR(M41T81_CCR_ADDRESS) | V_SMB_TT_WR2BYTE,
SMB_CSR(R_SMB_START));
while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
if (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_ERROR) {
/* Clear error bit by writing a 1 */
__raw_writeq(M_SMB_ERROR, SMB_CSR(R_SMB_STATUS));
return -1;
}
/* read the same byte again to make sure it is written */
__raw_writeq(V_SMB_ADDR(M41T81_CCR_ADDRESS) | V_SMB_TT_RD1BYTE,
SMB_CSR(R_SMB_START));
while (__raw_readq(SMB_CSR(R_SMB_STATUS)) & M_SMB_BUSY)
;
return 0;
}
int m41t81_set_time(time64_t t)
{
struct rtc_time tm;
unsigned long flags;
/* Note we don't care about the century */
rtc_time64_to_tm(t, &tm);
/*
* Note the write order matters as it ensures the correctness.
* When we write sec, 10th sec is clear. It is reasonable to
* believe we should finish writing min within a second.
*/
spin_lock_irqsave(&rtc_lock, flags);
tm.tm_sec = bin2bcd(tm.tm_sec);
m41t81_write(M41T81REG_SC, tm.tm_sec);
tm.tm_min = bin2bcd(tm.tm_min);
m41t81_write(M41T81REG_MN, tm.tm_min);
tm.tm_hour = bin2bcd(tm.tm_hour);
tm.tm_hour = (tm.tm_hour & 0x3f) | (m41t81_read(M41T81REG_HR) & 0xc0);
m41t81_write(M41T81REG_HR, tm.tm_hour);
/* tm_wday starts from 0 to 6 */
if (tm.tm_wday == 0) tm.tm_wday = 7;
tm.tm_wday = bin2bcd(tm.tm_wday);
m41t81_write(M41T81REG_DY, tm.tm_wday);
tm.tm_mday = bin2bcd(tm.tm_mday);
m41t81_write(M41T81REG_DT, tm.tm_mday);
/* tm_mon starts from 0, *ick* */
tm.tm_mon ++;
tm.tm_mon = bin2bcd(tm.tm_mon);
m41t81_write(M41T81REG_MO, tm.tm_mon);
/* we don't do century, everything is beyond 2000 */
tm.tm_year %= 100;
tm.tm_year = bin2bcd(tm.tm_year);
m41t81_write(M41T81REG_YR, tm.tm_year);
spin_unlock_irqrestore(&rtc_lock, flags);
return 0;
}
time64_t m41t81_get_time(void)
{
unsigned int year, mon, day, hour, min, sec;
unsigned long flags;
/*
* min is valid if two reads of sec are the same.
*/
for (;;) {
spin_lock_irqsave(&rtc_lock, flags);
sec = m41t81_read(M41T81REG_SC);
min = m41t81_read(M41T81REG_MN);
if (sec == m41t81_read(M41T81REG_SC)) break;
spin_unlock_irqrestore(&rtc_lock, flags);
}
hour = m41t81_read(M41T81REG_HR) & 0x3f;
day = m41t81_read(M41T81REG_DT);
mon = m41t81_read(M41T81REG_MO);
year = m41t81_read(M41T81REG_YR);
spin_unlock_irqrestore(&rtc_lock, flags);
sec = bcd2bin(sec);
min = bcd2bin(min);
hour = bcd2bin(hour);
day = bcd2bin(day);
mon = bcd2bin(mon);
year = bcd2bin(year);
year += 2000;
return mktime64(year, mon, day, hour, min, sec);
}
int m41t81_probe(void)
{
unsigned int tmp;
/* enable chip if it is not enabled yet */
tmp = m41t81_read(M41T81REG_SC);
m41t81_write(M41T81REG_SC, tmp & 0x7f);
return m41t81_read(M41T81REG_SC) != -1;
}
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