From 1f21d2bde0046e959b53756f74d96dfd040a803b Mon Sep 17 00:00:00 2001 From: Brian Murphy Date: Tue, 21 Aug 2007 22:34:16 +0200 Subject: [MIPS] Add back support for LASAT platforms Signed-off-by: Brian Murphy Signed-off-by: Ralf Baechle --- arch/mips/lasat/ds1603.c | 183 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 183 insertions(+) create mode 100644 arch/mips/lasat/ds1603.c (limited to 'arch/mips/lasat/ds1603.c') diff --git a/arch/mips/lasat/ds1603.c b/arch/mips/lasat/ds1603.c new file mode 100644 index 00000000000..0b315f51d62 --- /dev/null +++ b/arch/mips/lasat/ds1603.c @@ -0,0 +1,183 @@ +/* + * Dallas Semiconductors 1603 RTC driver + * + * Brian Murphy + * + */ +#include +#include +#include +#include +#include + +#include "ds1603.h" + +#define READ_TIME_CMD 0x81 +#define SET_TIME_CMD 0x80 +#define TRIMMER_SET_CMD 0xC0 +#define TRIMMER_VALUE_MASK 0x38 +#define TRIMMER_SHIFT 3 + +struct ds_defs *ds1603; + +/* HW specific register functions */ +static void rtc_reg_write(unsigned long val) +{ + *ds1603->reg = val; +} + +static unsigned long rtc_reg_read(void) +{ + unsigned long tmp = *ds1603->reg; + return tmp; +} + +static unsigned long rtc_datareg_read(void) +{ + unsigned long tmp = *ds1603->data_reg; + return tmp; +} + +static void rtc_nrst_high(void) +{ + rtc_reg_write(rtc_reg_read() | ds1603->rst); +} + +static void rtc_nrst_low(void) +{ + rtc_reg_write(rtc_reg_read() & ~ds1603->rst); +} + +static void rtc_cycle_clock(unsigned long data) +{ + data |= ds1603->clk; + rtc_reg_write(data); + lasat_ndelay(250); + if (ds1603->data_reversed) + data &= ~ds1603->data; + else + data |= ds1603->data; + data &= ~ds1603->clk; + rtc_reg_write(data); + lasat_ndelay(250 + ds1603->huge_delay); +} + +static void rtc_write_databit(unsigned int bit) +{ + unsigned long data = rtc_reg_read(); + if (ds1603->data_reversed) + bit = !bit; + if (bit) + data |= ds1603->data; + else + data &= ~ds1603->data; + + rtc_reg_write(data); + lasat_ndelay(50 + ds1603->huge_delay); + rtc_cycle_clock(data); +} + +static unsigned int rtc_read_databit(void) +{ + unsigned int data; + + data = (rtc_datareg_read() & (1 << ds1603->data_read_shift)) + >> ds1603->data_read_shift; + rtc_cycle_clock(rtc_reg_read()); + return data; +} + +static void rtc_write_byte(unsigned int byte) +{ + int i; + + for (i = 0; i <= 7; i++) { + rtc_write_databit(byte & 1L); + byte >>= 1; + } +} + +static void rtc_write_word(unsigned long word) +{ + int i; + + for (i = 0; i <= 31; i++) { + rtc_write_databit(word & 1L); + word >>= 1; + } +} + +static unsigned long rtc_read_word(void) +{ + int i; + unsigned long word = 0; + unsigned long shift = 0; + + for (i = 0; i <= 31; i++) { + word |= rtc_read_databit() << shift; + shift++; + } + return word; +} + +static void rtc_init_op(void) +{ + rtc_nrst_high(); + + rtc_reg_write(rtc_reg_read() & ~ds1603->clk); + + lasat_ndelay(50); +} + +static void rtc_end_op(void) +{ + rtc_nrst_low(); + lasat_ndelay(1000); +} + +/* interface */ +unsigned long ds1603_read(void) +{ + unsigned long word; + unsigned long flags; + + spin_lock_irqsave(&rtc_lock, flags); + rtc_init_op(); + rtc_write_byte(READ_TIME_CMD); + word = rtc_read_word(); + rtc_end_op(); + spin_unlock_irqrestore(&rtc_lock, flags); + return word; +} + +int ds1603_set(unsigned long time) +{ + unsigned long flags; + + spin_lock_irqsave(&rtc_lock, flags); + rtc_init_op(); + rtc_write_byte(SET_TIME_CMD); + rtc_write_word(time); + rtc_end_op(); + spin_unlock_irqrestore(&rtc_lock, flags); + + return 0; +} + +void ds1603_set_trimmer(unsigned int trimval) +{ + rtc_init_op(); + rtc_write_byte(((trimval << TRIMMER_SHIFT) & TRIMMER_VALUE_MASK) + | (TRIMMER_SET_CMD)); + rtc_end_op(); +} + +void ds1603_disable(void) +{ + ds1603_set_trimmer(TRIMMER_DISABLE_RTC); +} + +void ds1603_enable(void) +{ + ds1603_set_trimmer(TRIMMER_DEFAULT); +} -- cgit v1.2.3