For the pwm driver I took a stab at a more holistic pin descriptor and wanted to solicit feedback and opinions.
The core is in mcu.h: https://github.com/mlampert/mynewt-core/blob/feature/stm32-pwm-enabled/hw/mcu/stm/stm32f7xx/include/mcu/mcu.h Instead of using a struct data type I decided to go with bit encoding and macros, for the sole reason of API compatibility. A pin descriptor with an AF assignment can be passed to any API that accepts a pin (as long as the type is at least a uint16_t). For instance, it allows us to fold the functionality of hal_gpio_init_af into hal_gpio_init_in and hal_gpio_init_out and eliminate the stm specific api additions. Assuming the API allows a 32-bit pin type the encoding can be expanded to pin speed, strength, logic standard (although I haven't seen that in any of the ARMs - yet).... The other advantage of a bit encoding is that the entire pin descriptor can be defined in a single constant: /* AF=2 of PB7 */ #define PWM_PIN 0x2017 And if the GPIO pin is already defined: https://github.com/mlampert/mynewt-core/blob/feature/stm32-pwm-enabled/apps/pwm_test/src/main.c#L27 Internal use currently looks something like this: https://github.com/mlampert/mynewt-core/blob/feature/stm32-pwm-enabled/hw/drivers/pwm/pwm_stm32/src/pwm_stm32.c#L289 with the (stm) hal_gpio refactoring mentioned above that line would simple become: if (hal_gpio_init_out(cfg->pin, 0)) { I've only implemented this for the stm32f7 in order to reduce the refactoring effort if we want to go a different direction. Thoughts? Comments? ...
