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Merge pull request #5 from tingleby/master

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gpio: API cleaner & documentation fixed
This commit is contained in:
Brendan Le Foll
2014-04-29 17:18:14 +01:00
parent 34cbc434b0 ac995a8803
commit 7524cb7ab8
3 changed files with 153 additions and 25 deletions
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93
api/gpio.h
View File

@@ -27,21 +27,92 @@
#include <stdio.h>
#include "maa.h"
/**
* A strucutre representing a gpio pin.
*/
typedef struct {
int pin;
int pinMap;
char path[64];
FILE *value_fp;
/*@{*/
int pin; /**< the pin number, as known to the os. */
FILE *value_fp; /**< the file pointer to the value of the gpio /*
/*@}*/
} maa_gpio_context;
typedef char gpio_mode_t[16];
typedef char gpio_dir_t[16];
/**
* GPIO Output modes
*/
typedef enum {
MAA_GPIO_STRONG = 0, /**< Default. Strong high and low */
MAA_GPIO_PULLUP = 1, /**< Resistive High */
MAA_GPIO_PULLDOWN = 2, /**< Resistive Low */
MAA_GPIO_HIZ = 3 /**< High Z State */
} gpio_mode_t;
/**
* GPIO Direction options.
*/
typedef enum {
MAA_GPIO_OUT = 0, /**< Output. A Mode can also be set */
MAA_GPIO_IN = 1 /**< Input. */
} gpio_dir_t;
/** Initialise gpio_context, based on board number
*
* @param pin pin number read from the board, i.e IO3 is 3.
*
* @returns
* maa_gpio_context based on the IO pin
*/
maa_gpio_context* maa_gpio_init(int pin);
void maa_gpio_mode(maa_gpio_context *dev, gpio_mode_t mode);
void maa_gpio_dir(maa_gpio_context *dev, gpio_dir_t dir);
void maa_gpio_close(maa_gpio_context *dev);
/** Initialise gpio context without any mapping to a pin.
* - For more expert users
*
* @param gpiopin gpio pin as listed in SYSFS
*
* @return gpio context
*/
maa_gpio_context* maa_gpio_init_raw(int gpiopin);
/** Set GPIO Output Mode,
*
* @param dev The GPIO context
* @param mode The GPIO Output Mode.
*
* @return maa result type.
*/
maa_result_t maa_gpio_mode(maa_gpio_context *dev, gpio_mode_t mode);
/** Set GPIO direction
*
* @param dev The GPIO context.
* @param dir The direction of the GPIO.
*
* @return maa result type.
*/
maa_result_t maa_gpio_dir(maa_gpio_context *dev, gpio_dir_t dir);
/** Close the GPIO context
* - Will free the memory for the context.
*
* @param dev the GPIO context
*
* @return maa result type.
*/
maa_result_t maa_gpio_close(maa_gpio_context *dev);
/** Read the GPIO value.
*
* @param dev The GPIO context.
*
* @return the integer value of the GPIO
*/
int maa_gpio_read(maa_gpio_context *dev);
void maa_gpio_write(maa_gpio_context *dev, int value);
/** Write to the GPIO Value.
*
* @param dev The GPIO context.
* @param value Integer value to write.
*
* @return maa result type
*/
maa_result_t maa_gpio_write(maa_gpio_context *dev, int value);

2
examples/blink-io8.c
View File

@@ -33,7 +33,7 @@ main(int argc, char **argv)
maa_get_version());
maa_gpio_context* gpio;
gpio = maa_gpio_init(26);
maa_gpio_dir(gpio, "out");
maa_gpio_dir(gpio, MAA_GPIO_OUT);
while (1) {
maa_gpio_write(gpio, 0);

83
src/gpio/gpio.c
View File

@@ -43,12 +43,20 @@ maa_gpio_get_valfp(maa_gpio_context *dev)
maa_gpio_context*
maa_gpio_init(int pin)
{
//TODO
return maa_gpio_init_raw(pin);
}
maa_gpio_context*
maa_gpio_init_raw(int pin)
{
FILE *export_f;
maa_gpio_context* dev = (maa_gpio_context*) malloc(sizeof(maa_gpio_context));
if ((export_f = fopen("/sys/class/gpio/export", "w")) == NULL) {
fprintf(stderr, "Failed to open export for writing!\n");
return NULL;
} else {
fprintf(export_f, "%d", pin);
fclose(export_f);
@@ -57,13 +65,44 @@ maa_gpio_init(int pin)
return dev;
}
void
maa_result_t
maa_gpio_mode(maa_gpio_context *dev, gpio_mode_t mode)
{
//gpio->pin
if (dev->value_fp != NULL) {
dev->value_fp = NULL;
}
char filepath[64];
snprintf(filepath, 64, "/sys/class/gpio/gpio%d/drive", dev->pin);
FILE *drive;
if ((drive = fopen(filepath, "w")) == NULL) {
fprintf(stderr, "Failed to open drive for writing!\n");
return MAA_ERROR_INVALID_RESOURCE;
}
switch(mode) {
case MAA_GPIO_STRONG:
fprintf(drive, "strong");
break;
case MAA_GPIO_PULLUP:
fprintf(drive, "pullup");
break;
case MAA_GPIO_PULLDOWN:
fprintf(drive, "pulldown");
break;
case MAA_GPIO_HIZ:
fprintf(drive, "hiz");
break;
default:
fclose(drive);
return MAA_ERROR_FEATURE_NOT_IMPLEMENTED;
break;
}
fclose(drive);
dev->value_fp = NULL;
return MAA_SUCCESS;
}
void
maa_result_t
maa_gpio_dir(maa_gpio_context *dev, gpio_dir_t dir)
{
if (dev->value_fp != NULL) {
@@ -75,11 +114,23 @@ maa_gpio_dir(maa_gpio_context *dev, gpio_dir_t dir)
FILE *direction;
if ((direction = fopen(filepath, "w")) == NULL) {
fprintf(stderr, "Failed to open direction for writing!\n");
} else {
fprintf(direction, dir);
fclose(direction);
dev->value_fp = NULL;
return MAA_ERROR_INVALID_RESOURCE;
}
switch(dir) {
case MAA_GPIO_OUT:
fprintf(direction, "out");
break;
case MAA_GPIO_IN:
fprintf(direction, "in");
break;
default:
fclose(direction);
return MAA_ERROR_FEATURE_NOT_IMPLEMENTED;
break;
}
fclose(direction);
dev->value_fp = NULL;
return MAA_SUCCESS;
}
int
@@ -95,7 +146,7 @@ maa_gpio_read(maa_gpio_context *dev)
return atoi(buffer);
}
void
maa_result_t
maa_gpio_write(maa_gpio_context *dev, int value)
{
if (dev->value_fp == NULL) {
@@ -104,18 +155,24 @@ maa_gpio_write(maa_gpio_context *dev, int value)
fseek(dev->value_fp, SEEK_SET, 0);
fprintf(dev->value_fp, "%d", value);
fseek(dev->value_fp, SEEK_SET, 0);
if (ferror(dev->value_fp) != 0)
return MAA_ERROR_INVALID_RESOURCE;
return MAA_SUCCESS;
}
void
maa_result_t
maa_gpio_close(maa_gpio_context *dev)
{
FILE *unexport_f;
if ((unexport_f = fopen("/sys/class/gpio/unexport", "w")) == NULL) {
fprintf(stderr, "Failed to open unexport for writing!\n");
} else {
fprintf(unexport_f, "%d", dev->pin);
fclose(unexport_f);
return MAA_ERROR_INVALID_RESOURCE;
}
fprintf(unexport_f, "%d", dev->pin);
fclose(unexport_f);
if (ferror(dev->value_fp) != 0)
return MAA_ERROR_INVALID_RESOURCE;
free(dev);
return MAA_SUCCESS;
}