I like the proposed changes!

Fabio

On Sun, May 13, 2018, at 1:02 AM, markus wrote:
> 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? ...

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