arch-atmega/uart-mux-yun.c: document current behaviour
arch-atmega/uart-mux-yun: document new behaviour
arch-atmega/uart-mux-yun: implement new behaviour
lib: add trivial bathos shell
arch-atmega/uart-mux-yun: handle shell events
arch-atmega/arch/bathos-arch.h: new flip4 function

This function is useful for swapping bytes when a short 4-byte string
(label) needs to be transferred as an integer, thus working around the
little endiannes of integers.

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
save labels of yun board pin on mcu side, so that mpu will detect them.

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
arch-atmega/pwm.c: timer1 decrease prescaler, increase resolution

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
D11 output now used as OC1C (was OC0A)

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
struct pwm: new fields tim_res_ns and tim_max_mul

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
arch-atmega/pwm.c: do not modify TCCR0B register, since it is used by system clock.

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
arch-atmega: pwm implementation rewritten using function pointers (ops)

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
arch-atmega/pwm: new interface, based on period/duty multipliers of time resolution

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
arch-atmega/pwm.c: fix tim_res_ns of OC0B

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
arch-atmega/pwm.c: fix set_ and get_period timer1 (period is ICR1 + 1)

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
pwm: fix pwm_get_period_default

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
trivial arch-atmega/pwm.c: fix indentation

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
drivers/w1-temp.c: fix warning: left shift count >= width of type

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
arch-atmega/pwm.c: implemented pwm on 3A output (D5 on yun board)

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>
tasks/mcuio_pwm_func.c: use register 0x4 as 'capabilities'

Signed-off-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>