diff options
Diffstat (limited to 'src/include/gpio.h')
| -rw-r--r-- | src/include/gpio.h | 36 |
1 files changed, 35 insertions, 1 deletions
diff --git a/src/include/gpio.h b/src/include/gpio.h index ea03a23231..4627e4412c 100644 --- a/src/include/gpio.h +++ b/src/include/gpio.h @@ -29,6 +29,7 @@ void gpio_input_pulldown(gpio_t gpio); void gpio_input_pullup(gpio_t gpio); void gpio_input(gpio_t gpio); void gpio_output(gpio_t gpio, int value); +int _gpio_base3_value(gpio_t gpio[], int num_gpio, int binary_first); /* * Read the value presented by the set of GPIOs, when each pin is interpreted @@ -48,6 +49,39 @@ int gpio_base2_value(gpio_t gpio[], int num_gpio); * gpio[]: pin positions to read. gpio[0] is less significant than gpio[1]. * num_gpio: number of pins to read. */ -int gpio_base3_value(gpio_t gpio[], int num_gpio); +static inline int gpio_base3_value(gpio_t gpio[], int num_gpio) +{ + return _gpio_base3_value(gpio, num_gpio, 0); +} + +/* + * Read the value presented by the set of GPIOs, when each pin is interpreted + * as a base-3 digit (LOW = 0, HIGH = 1, Z/floating = 2) in a non-standard + * ternary number system where the first 2^n natural numbers are represented + * as they would be in a binary system (without any Z digits), and the following + * 3^n-2^n numbers use the remaining ternary representations in the normal + * ternary system order (skipping the values that were already used up). + * This is useful for boards which initially used a binary board ID and later + * decided to switch to tri-state after some revisions have already been built. + * Example: For num_gpio = 2 we get the following representation: + * + * Number X1 X0 + * 0 0 0 + * 1 0 1 + * 2 1 0 + * 3 1 1 // Start counting ternaries back at 0 after this + * 4 0 2 // Skipping 00 and 01 which are already used up + * 5 1 2 // Skipping 10 and 11 which are already used up + * 6 2 0 + * 7 2 1 + * 8 2 2 + * + * gpio[]: pin positions to read. gpio[0] is less significant than gpio[1]. + * num_gpio: number of pins to read. + */ +static inline int gpio_binary_first_base3_value(gpio_t gpio[], int num_gpio) +{ + return _gpio_base3_value(gpio, num_gpio, 1); +} #endif /* __SRC_INCLUDE_GPIO_H__ */ |