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bouwhuim.nikhef.nl dee2668a61 newest version WRPC
2013-09-10 08:08:59 +00:00

76 lines
1.9 KiB
C

/*
* This work is part of the White Rabbit project
*
* Copyright (C) 2013 CERN (www.cern.ch)
* Author: Alessandro Rubini <rubini@gnudd.com>
*
* Released according to the GNU GPL, version 2 or any later version.
*/
#include <wrc.h>
#include <string.h>
#include <w1.h>
#include <hw/sockit_owm_regs.h>
static inline uint32_t __wait_cycle(void *base)
{
uint32_t reg;
while ((reg = IORD_SOCKIT_OWM_CTL(base)) & SOCKIT_OWM_CTL_CYC_MSK)
;
return reg;
}
static int w1_reset(struct w1_bus *bus)
{
int portnum = bus->detail;
uint32_t reg;
IOWR_SOCKIT_OWM_CTL(BASE_ONEWIRE, (portnum << SOCKIT_OWM_CTL_SEL_OFST)
| (SOCKIT_OWM_CTL_CYC_MSK)
| (SOCKIT_OWM_CTL_RST_MSK));
reg = __wait_cycle(BASE_ONEWIRE);
/* return presence-detect pulse (1 if true) */
return (reg & SOCKIT_OWM_CTL_DAT_MSK) ? 0 : 1;
}
static int w1_read_bit(struct w1_bus *bus)
{
int portnum = bus->detail;
uint32_t reg;
IOWR_SOCKIT_OWM_CTL(BASE_ONEWIRE, (portnum << SOCKIT_OWM_CTL_SEL_OFST)
| (SOCKIT_OWM_CTL_CYC_MSK)
| (SOCKIT_OWM_CTL_DAT_MSK));
reg = __wait_cycle(BASE_ONEWIRE);
return (reg & SOCKIT_OWM_CTL_DAT_MSK) ? 1 : 0;
}
static void w1_write_bit(struct w1_bus *bus, int bit)
{
int portnum = bus->detail;
IOWR_SOCKIT_OWM_CTL(BASE_ONEWIRE, (portnum << SOCKIT_OWM_CTL_SEL_OFST)
| (SOCKIT_OWM_CTL_CYC_MSK)
| (bit ? SOCKIT_OWM_CTL_DAT_MSK : 0));
__wait_cycle(BASE_ONEWIRE);
}
struct w1_ops wrpc_w1_ops = {
.reset = w1_reset,
.read_bit = w1_read_bit,
.write_bit = w1_write_bit,
};
struct w1_bus wrpc_w1_bus;
/* Init from sockitowm code */
#define CLK_DIV_NOR (CPU_CLOCK / 200000 - 1) /* normal mode */
#define CLK_DIV_OVD (CPU_CLOCK / 1000000 - 1) /* overdrive mode (not used) */
void wrpc_w1_init(void)
{
IOWR_SOCKIT_OWM_CDR(BASE_ONEWIRE,
((CLK_DIV_NOR & SOCKIT_OWM_CDR_N_MSK) |
((CLK_DIV_OVD << SOCKIT_OWM_CDR_O_OFST) &
SOCKIT_OWM_CDR_O_MSK)));
}