linux/arch/mips/lasat/ds1603.c
Ralf Baechle 4b550488f8 [MIPS] Deforest the function pointer jungle in the time code.
Hard to follow who is pointing what to where and why so it's simply getting
in the way of the time code renovation.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11 23:46:08 +01:00

184 lines
3.1 KiB
C

/*
* Dallas Semiconductors 1603 RTC driver
*
* Brian Murphy <brian@murphy.dk>
*
*/
#include <linux/kernel.h>
#include <asm/lasat/lasat.h>
#include <linux/delay.h>
#include <asm/lasat/ds1603.h>
#include <asm/time.h>
#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);
}
unsigned long read_persistent_clock(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 rtc_mips_set_mmss(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);
}