gpio: add advanced open functions for cdev implementation

resolves #22.
vsergeev · May 29, 2020 · 7e7b91a · 7e7b91a
1 parent 0f20c96
commit 7e7b91a
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Showing 4 changed files with 141 additions and 22 deletions.
diff --git a/docs/gpio.md b/docs/gpio.md
@@ -11,6 +11,8 @@ GPIO wrapper functions for Linux userspace character device `gpio-cdev` and sysf
 gpio_t *gpio_new(void);
 int gpio_open(gpio_t *gpio, const char *path, unsigned int line, gpio_direction_t direction);
 int gpio_open_name(gpio_t *gpio, const char *path, const char *name, gpio_direction_t direction);
+int gpio_open_advanced(gpio_t *gpio, const char *path, unsigned int line, const gpio_config_t *config);
+int gpio_open_name_advanced(gpio_t *gpio, const char *path, const char *name, const gpio_config_t *config);
 int gpio_open_sysfs(gpio_t *gpio, unsigned int line, gpio_direction_t direction);
 int gpio_read(gpio_t *gpio, bool *value);
 int gpio_write(gpio_t *gpio, bool value);
@@ -111,6 +113,46 @@ Returns 0 on success, or a negative [GPIO error code](#return-value) on failure.
 
 ------
 
+``` c
+typedef struct gpio_config {
+    gpio_direction_t direction;
+    gpio_edge_t edge;
+    gpio_bias_t bias;
+    gpio_drive_t drive;
+    bool inverted;
+    const char *label;
+} gpio_config_t;
+
+int gpio_open_advanced(gpio_t *gpio, const char *path, unsigned int line, const gpio_config_t *config);
+```
+Open the character device GPIO with the specified GPIO line and configuration at the specified character device GPIO chip path (e.g. `/dev/gpiochip0`).
+
+`gpio` should be a valid pointer to an allocated GPIO handle structure. `path` is the GPIO chip character device path. `line` is the GPIO line number. `config` should be a valid pointer to a `gpio_config_t` structure with valid values. `label` can be `NULL` for a default consumer label.
+
+Returns 0 on success, or a negative [GPIO error code](#return-value) on failure.
+
+------
+
+``` c
+typedef struct gpio_config {
+    gpio_direction_t direction;
+    gpio_edge_t edge;
+    gpio_bias_t bias;
+    gpio_drive_t drive;
+    bool inverted;
+    const char *label;
+} gpio_config_t;
+
+int gpio_open_name_advanced(gpio_t *gpio, const char *path, const char *name, const gpio_config_t *config);
+```
+Open the character device GPIO with the specified GPIO name and configuration at the specified character device GPIO chip path (e.g. `/dev/gpiochip0`).
+
+`gpio` should be a valid pointer to an allocated GPIO handle structure. `path` is the GPIO chip character device path. `name` is the GPIO line name. `config` should be a valid pointer to a `gpio_config_t` structure with valid values. `label` can be `NULL` for a default consumer label.
+
+Returns 0 on success, or a negative [GPIO error code](#return-value) on failure.
+
+------
+
 ``` c
 int gpio_open_sysfs(gpio_t *gpio, unsigned int line, gpio_direction_t direction);
 ```

diff --git a/src/gpio.c b/src/gpio.c
@@ -1247,12 +1247,27 @@ static const struct gpio_ops gpio_cdev_ops = {
     .tostring = gpio_cdev_tostring,
 };
 
-int gpio_open(gpio_t *gpio, const char *path, unsigned int line, gpio_direction_t direction) {
+int gpio_open_advanced(gpio_t *gpio, const char *path, unsigned int line, const gpio_config_t *config) {
     int ret, fd;
 
-    if (direction != GPIO_DIR_IN && direction != GPIO_DIR_OUT && direction != GPIO_DIR_OUT_LOW && direction != GPIO_DIR_OUT_HIGH)
+    if (config->direction != GPIO_DIR_IN && config->direction != GPIO_DIR_OUT && config->direction != GPIO_DIR_OUT_LOW && config->direction != GPIO_DIR_OUT_HIGH)
         return _gpio_error(gpio, GPIO_ERROR_ARG, 0, "Invalid GPIO direction (can be in, out, low, high)");
 
+    if (config->edge != GPIO_EDGE_NONE && config->edge != GPIO_EDGE_RISING && config->edge != GPIO_EDGE_FALLING && config->edge != GPIO_EDGE_BOTH)
+        return _gpio_error(gpio, GPIO_ERROR_ARG, 0, "Invalid GPIO interrupt edge (can be none, rising, falling, both)");
+
+    if (config->direction != GPIO_DIR_IN && config->edge != GPIO_EDGE_NONE)
+        return _gpio_error(gpio, GPIO_ERROR_ARG, 0, "Invalid GPIO edge for output GPIO");
+
+    if (config->bias != GPIO_BIAS_DEFAULT && config->bias != GPIO_BIAS_PULL_UP && config->bias != GPIO_BIAS_PULL_DOWN && config->bias != GPIO_BIAS_DISABLE)
+        return _gpio_error(gpio, GPIO_ERROR_ARG, 0, "Invalid GPIO line bias (can be default, pull_up, pull_down, disable)");
+
+    if (config->drive != GPIO_DRIVE_DEFAULT && config->drive != GPIO_DRIVE_OPEN_DRAIN && config->drive != GPIO_DRIVE_OPEN_SOURCE)
+        return _gpio_error(gpio, GPIO_ERROR_ARG, 0, "Invalid GPIO line drive (can be default, open_drain, open_source)");
+
+    if (config->direction == GPIO_DIR_IN && config->drive != GPIO_DRIVE_DEFAULT)
+        return _gpio_error(gpio, GPIO_ERROR_ARG, 0, "Invalid GPIO line drive for input GPIO");
+
     /* Open GPIO chip */
     if ((fd = open(path, 0)) < 0)
         return _gpio_error(gpio, GPIO_ERROR_OPEN, errno, "Opening GPIO chip");
@@ -1262,10 +1277,11 @@ int gpio_open(gpio_t *gpio, const char *path, unsigned int line, gpio_direction_
     gpio->u.cdev.line = line;
     gpio->u.cdev.line_fd = -1;
     gpio->u.cdev.chip_fd = fd;
-    strncpy(gpio->u.cdev.label, "periphery", sizeof(gpio->u.cdev.label));
+    strncpy(gpio->u.cdev.label, config->label ? config->label : "periphery", sizeof(gpio->u.cdev.label));
+    gpio->u.cdev.label[sizeof(gpio->u.cdev.label) - 1] = '\0';
 
     /* Open GPIO line */
-    ret = _gpio_cdev_reopen(gpio, direction, GPIO_EDGE_NONE, GPIO_BIAS_DEFAULT, GPIO_DRIVE_DEFAULT, false);
+    ret = _gpio_cdev_reopen(gpio, config->direction, config->edge, config->bias, config->drive, config->inverted);
     if (ret < 0) {
         close(fd);
         return ret;
@@ -1274,11 +1290,8 @@ int gpio_open(gpio_t *gpio, const char *path, unsigned int line, gpio_direction_
     return 0;
 }
 
-int gpio_open_name(gpio_t *gpio, const char *path, const char *name, gpio_direction_t direction) {
-    int ret, fd;
-
-    if (direction != GPIO_DIR_IN && direction != GPIO_DIR_OUT && direction != GPIO_DIR_OUT_LOW && direction != GPIO_DIR_OUT_HIGH)
-        return _gpio_error(gpio, GPIO_ERROR_ARG, 0, "Invalid GPIO direction (can be in, out, low, high)");
+int gpio_open_name_advanced(gpio_t *gpio, const char *path, const char *name, const gpio_config_t *config) {
+    int fd;
 
     /* Open GPIO chip */
     if ((fd = open(path, 0)) < 0)
@@ -1316,19 +1329,34 @@ int gpio_open_name(gpio_t *gpio, const char *path, const char *name, gpio_direct
         return _gpio_error(gpio, GPIO_ERROR_NOT_FOUND, 0, "GPIO line \"%s\" not found by name", name);
     }
 
-    memset(gpio, 0, sizeof(gpio_t));
-    gpio->ops = &gpio_cdev_ops;
-    gpio->u.cdev.line = line;
-    gpio->u.cdev.line_fd = -1;
-    gpio->u.cdev.chip_fd = fd;
-    strncpy(gpio->u.cdev.label, "periphery", sizeof(gpio->u.cdev.label));
+    if (close(fd) < 0)
+        return _gpio_error(gpio, GPIO_ERROR_CLOSE, errno, "Closing GPIO chip");
 
-    /* Open GPIO line */
-    ret = _gpio_cdev_reopen(gpio, direction, GPIO_EDGE_NONE, GPIO_BIAS_DEFAULT, GPIO_DRIVE_DEFAULT, false);
-    if (ret < 0) {
-        close(fd);
-        return ret;
-    }
+    return gpio_open_advanced(gpio, path, line, config);
+}
 
-    return 0;
+int gpio_open(gpio_t *gpio, const char *path, unsigned int line, gpio_direction_t direction) {
+    gpio_config_t config = {
+        .direction = direction,
+        .edge = GPIO_EDGE_NONE,
+        .bias = GPIO_BIAS_DEFAULT,
+        .drive = GPIO_DRIVE_DEFAULT,
+        .inverted = false,
+        .label = NULL,
+    };
+
+    return gpio_open_advanced(gpio, path, line, &config);
+}
+
+int gpio_open_name(gpio_t *gpio, const char *path, const char *name, gpio_direction_t direction) {
+    gpio_config_t config = {
+        .direction = direction,
+        .edge = GPIO_EDGE_NONE,
+        .bias = GPIO_BIAS_DEFAULT,
+        .drive = GPIO_DRIVE_DEFAULT,
+        .inverted = false,
+        .label = NULL,
+    };
+
+    return gpio_open_name_advanced(gpio, path, name, &config);
 }
diff --git a/src/gpio.h b/src/gpio.h
@@ -54,12 +54,24 @@ typedef enum gpio_drive {
     GPIO_DRIVE_OPEN_SOURCE, /* Open source */
 } gpio_drive_t;
 
+/* Configuration structure for gpio_open_*advanced() functions */
+typedef struct gpio_config {
+    gpio_direction_t direction;
+    gpio_edge_t edge;
+    gpio_bias_t bias;
+    gpio_drive_t drive;
+    bool inverted;
+    const char *label; /* Can be NULL for default consumer label */
+} gpio_config_t;
+
 typedef struct gpio_handle gpio_t;
 
 /* Primary Functions */
 gpio_t *gpio_new(void);
 int gpio_open(gpio_t *gpio, const char *path, unsigned int line, gpio_direction_t direction);
 int gpio_open_name(gpio_t *gpio, const char *path, const char *name, gpio_direction_t direction);
+int gpio_open_advanced(gpio_t *gpio, const char *path, unsigned int line, const gpio_config_t *config);
+int gpio_open_name_advanced(gpio_t *gpio, const char *path, const char *name, const gpio_config_t *config);
 int gpio_open_sysfs(gpio_t *gpio, unsigned int line, gpio_direction_t direction);
 int gpio_read(gpio_t *gpio, bool *value);
 int gpio_write(gpio_t *gpio, bool value);

diff --git a/tests/test_gpio.c b/tests/test_gpio.c
@@ -173,6 +173,43 @@ void test_open_config_close(void) {
     /* Close GPIO */
     passert(gpio_close(gpio) == 0);
 
+    /* Open GPIO with advanced open */
+    gpio_config_t config = {
+        .direction = GPIO_DIR_IN,
+        .edge = GPIO_EDGE_RISING,
+        .bias = GPIO_BIAS_DEFAULT,
+        .drive = GPIO_DRIVE_DEFAULT,
+        .inverted = false,
+        .label = "test123",
+    };
+    passert(gpio_open_advanced(gpio, device, pin_input, &config) == 0);
+
+    /* Check properties */
+    passert(gpio_line(gpio) == pin_input);
+    passert(gpio_fd(gpio) >= 0);
+    passert(gpio_chip_fd(gpio) >= 0);
+    /* Check direction */
+    passert(gpio_get_direction(gpio, &direction) == 0);
+    passert(direction == GPIO_DIR_IN);
+    /* Check edge */
+    passert(gpio_get_edge(gpio, &edge) == 0);
+    passert(edge == GPIO_EDGE_RISING);
+    /* Check bias */
+    passert(gpio_get_bias(gpio, &bias) == 0);
+    passert(bias == GPIO_BIAS_DEFAULT);
+    /* Check drive */
+    passert(gpio_get_drive(gpio, &drive) == 0);
+    passert(drive == GPIO_DRIVE_DEFAULT);
+    /* Check inverted */
+    passert(gpio_get_inverted(gpio, &inverted) == 0);
+    passert(inverted == false);
+    /* Check label */
+    passert(gpio_label(gpio, label, sizeof(label)) == 0);
+    passert(strncmp(label, "test123", sizeof(label)) == 0);
+
+    /* Close GPIO */
+    passert(gpio_close(gpio) == 0);
+
     /* Free GPIO */
     gpio_free(gpio);
 }