Skip to content

Commit

Permalink
uart_ow: add ow specific context and store search state there
Browse files Browse the repository at this point in the history 
Signed-off-by: Jon Trulson <[email protected]>
Signed-off-by: Brendan Le Foll <[email protected]>
  • Loading branch information
@jontrulson @arfoll
jontrulson authored and arfoll committed May 4, 2016
1 parent a702cdf commit f6d9cf5
Show file tree
Hide file tree
Showing 2 changed files with 58 additions and 41 deletions.
10 changes: 9 additions & 1 deletion api/mraa/uart_ow.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -62,9 +62,17 @@ extern "C" {
#include <stdio.h>

#include "common.h"
#include "uart.h"

/* for now, we simply use the normal MRAA UART context */
typedef struct _uart* mraa_uart_ow_context;
typedef struct _mraa_uart_ow {
mraa_uart_context uart;
/* search state */
unsigned char ROM_NO[8]; /* 8 byte (64b) rom code */
int LastDiscrepancy;
int LastFamilyDiscrepancy;
mraa_boolean_t LastDeviceFlag;
} *mraa_uart_ow_context;

/* 8 bytes (64 bits) for a device rom code */
static const int MRAA_UART_OW_ROMCODE_SIZE = 8;
Expand Down
89 changes: 49 additions & 40 deletions src/uart_ow/uart_ow.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,17 +40,11 @@
#include "uart_ow.h"
#include "mraa_internal.h"

// global search state
static unsigned char ROM_NO[8]; /* 8 byte (64b) rom code */
static int LastDiscrepancy;
static int LastFamilyDiscrepancy;
static mraa_boolean_t LastDeviceFlag;

// low-level read byte
static mraa_result_t
_ow_read_byte(mraa_uart_ow_context dev, uint8_t *ch)
{
while (!mraa_uart_read(dev, (char*) ch, 1))
while (!mraa_uart_read(dev->uart, (char*) ch, 1))
;

return MRAA_SUCCESS;
Expand All @@ -60,7 +54,7 @@ _ow_read_byte(mraa_uart_ow_context dev, uint8_t *ch)
static int
_ow_write_byte(mraa_uart_ow_context dev, const char ch)
{
return mraa_uart_write(dev, &ch, 1);
return mraa_uart_write(dev->uart, &ch, 1);
}

// Here we setup a very simple termios with the minimum required
Expand All @@ -69,7 +63,7 @@ _ow_write_byte(mraa_uart_ow_context dev, const char ch)
// high speed (115200 bd) for actual data communications.
//
static mraa_result_t
_ow_set_speed(mraa_uart_context dev, mraa_boolean_t speed)
_ow_set_speed(mraa_uart_ow_context dev, mraa_boolean_t speed)
{

if (!dev) {
Expand All @@ -89,10 +83,10 @@ _ow_set_speed(mraa_uart_context dev, mraa_boolean_t speed)
.c_cflag = baud | CS8 | CLOCAL | CREAD, .c_iflag = 0, .c_oflag = 0, .c_lflag = NOFLSH, .c_cc = { 0 },
};

tcflush(dev->fd, TCIFLUSH);
tcflush(dev->uart->fd, TCIFLUSH);

// TCSANOW is required
if (tcsetattr(dev->fd, TCSANOW, &termio) < 0) {
if (tcsetattr(dev->uart->fd, TCSANOW, &termio) < 0) {
syslog(LOG_ERR, "uart_ow: tcsetattr() failed");
return MRAA_ERROR_INVALID_RESOURCE;
}
Expand Down Expand Up @@ -121,13 +115,13 @@ _ow_search(mraa_uart_ow_context dev)
search_result = 0;

// if the last call was not the last device
if (!LastDeviceFlag) {
if (!dev->LastDeviceFlag) {
// 1-Wire reset
if (mraa_uart_ow_reset(dev) != MRAA_SUCCESS) {
// reset the search
LastDiscrepancy = 0;
LastDeviceFlag = 0;
LastFamilyDiscrepancy = 0;
dev->LastDiscrepancy = 0;
dev->LastDeviceFlag = 0;
dev->LastFamilyDiscrepancy = 0;
return 0;
}

Expand All @@ -150,26 +144,26 @@ _ow_search(mraa_uart_ow_context dev)
else {
// if this discrepancy if before the Last Discrepancy
// on a previous next then pick the same as last time
if (id_bit_number < LastDiscrepancy)
search_direction = ((ROM_NO[rom_byte_number] & rom_byte_mask) > 0);
if (id_bit_number < dev->LastDiscrepancy)
search_direction = ((dev->ROM_NO[rom_byte_number] & rom_byte_mask) > 0);
else
// if equal to last pick 1, if not then pick 0
search_direction = (id_bit_number == LastDiscrepancy);
search_direction = (id_bit_number == dev->LastDiscrepancy);
// if 0 was picked then record its position in LastZero
if (search_direction == 0) {
last_zero = id_bit_number;
// check for Last discrepancy in family
if (last_zero < 9)
LastFamilyDiscrepancy = last_zero;
dev->LastFamilyDiscrepancy = last_zero;
}
}

// set or clear the bit in the ROM byte rom_byte_number
// with mask rom_byte_mask
if (search_direction == 1)
ROM_NO[rom_byte_number] |= rom_byte_mask;
dev->ROM_NO[rom_byte_number] |= rom_byte_mask;
else
ROM_NO[rom_byte_number] &= ~rom_byte_mask;
dev->ROM_NO[rom_byte_number] &= ~rom_byte_mask;

// serial number search direction write bit
mraa_uart_ow_bit(dev, search_direction);
Expand All @@ -192,21 +186,21 @@ _ow_search(mraa_uart_ow_context dev)
if (id_bit_number >= 65) {
// search successful so set
// LastDiscrepancy,LastDeviceFlag,search_result
LastDiscrepancy = last_zero;
dev->LastDiscrepancy = last_zero;

// check for last device
if (LastDiscrepancy == 0)
LastDeviceFlag = 1;
if (dev->LastDiscrepancy == 0)
dev->LastDeviceFlag = 1;
}
search_result = 1;
}

// if no device found then reset counters so next 'search' will be
// like a first
if (!search_result || !ROM_NO[0]) {
LastDiscrepancy = 0;
LastDeviceFlag = 0;
LastFamilyDiscrepancy = 0;
if (!search_result || !dev->ROM_NO[0]) {
dev->LastDiscrepancy = 0;
dev->LastDeviceFlag = 0;
dev->LastFamilyDiscrepancy = 0;
search_result = 0;
}

Expand All @@ -222,9 +216,9 @@ static mraa_boolean_t
_ow_first(mraa_uart_ow_context dev)
{
// reset the search state
LastDiscrepancy = 0;
LastDeviceFlag = 0;
LastFamilyDiscrepancy = 0;
dev->LastDiscrepancy = 0;
dev->LastDeviceFlag = 0;
dev->LastFamilyDiscrepancy = 0;

return _ow_search(dev);
}
Expand All @@ -246,13 +240,20 @@ _ow_next(mraa_uart_ow_context dev)
mraa_uart_ow_context
mraa_uart_ow_init(int index)
{
mraa_uart_ow_context dev = mraa_uart_init(index);

mraa_uart_ow_context dev = calloc(1, sizeof(struct _mraa_uart_ow));
if (!dev)
return NULL;

dev->uart = mraa_uart_init(index);
if (!dev->uart)
{
free(dev);
return NULL;
}


// now get the fd, and set it up for non-blocking operation
if (fcntl(dev->fd, F_SETFL, O_NONBLOCK) == -1) {
if (fcntl(dev->uart->fd, F_SETFL, O_NONBLOCK) == -1) {
syslog(LOG_ERR, "uart_ow: failed to set non-blocking on fd");
mraa_uart_ow_stop(dev);
return NULL;
Expand All @@ -264,13 +265,19 @@ mraa_uart_ow_init(int index)
mraa_uart_ow_context
mraa_uart_ow_init_raw(const char* path)
{
mraa_uart_ow_context dev = mraa_uart_init_raw(path);

mraa_uart_ow_context dev = calloc(1, sizeof(struct _mraa_uart_ow));
if (!dev)
return NULL;

dev->uart = mraa_uart_init_raw(path);
if (!dev->uart)
{
free(dev);
return NULL;
}

// now get the fd, and set it up for non-blocking operation
if (fcntl(dev->fd, F_SETFL, O_NONBLOCK) == -1) {
if (fcntl(dev->uart->fd, F_SETFL, O_NONBLOCK) == -1) {
syslog(LOG_ERR, "uart_ow: failed to set non-blocking on fd");
mraa_uart_ow_stop(dev);
return NULL;
Expand All @@ -282,13 +289,15 @@ mraa_uart_ow_init_raw(const char* path)
mraa_result_t
mraa_uart_ow_stop(mraa_uart_ow_context dev)
{
return mraa_uart_stop(dev);
mraa_result_t rv = mraa_uart_stop(dev->uart);
free(dev);
return rv;
}

const char*
mraa_uart_ow_get_dev_path(mraa_uart_ow_context dev)
{
return mraa_uart_get_dev_path(dev);
return mraa_uart_get_dev_path(dev->uart);
}

int
Expand Down Expand Up @@ -438,7 +447,7 @@ mraa_uart_ow_rom_search(mraa_uart_ow_context dev, mraa_boolean_t start, uint8_t*
// found one. Copy into id and return 1
int i;
for (i = 0; i < MRAA_UART_OW_ROMCODE_SIZE; i++)
id[i] = ROM_NO[i];
id[i] = dev->ROM_NO[i];

return MRAA_SUCCESS;
} else
Expand Down

0 comments on commit f6d9cf5

Please sign in to comment.