diff options
Diffstat (limited to 'arch/mips/sibyte/swarm/rtc_m41t81.c')
| -rw-r--r-- | arch/mips/sibyte/swarm/rtc_m41t81.c | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/arch/mips/sibyte/swarm/rtc_m41t81.c b/arch/mips/sibyte/swarm/rtc_m41t81.c new file mode 100644 index 000000000..afe1e3460 --- /dev/null +++ b/arch/mips/sibyte/swarm/rtc_m41t81.c @@ -0,0 +1,228 @@ +// 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; +} |