[PATCH v6 1/3] serial: sh-sci: Add OF support

[hechtb@gmail.com (Bastian Hecht)]

Hi Laurent,

>> +- renesas,scscr : Should contain a bitfield used by the Serial Control
>> Register.
>> +  b7 = SCSCR_TIE
>> +  b6 = SCSCR_RIE
>> +  b5 = SCSCR_TE
>> +  b4 = SCSCR_RE
>> +  b3 = SCSCR_REIE
>> +  b2 = SCSCR_TOIE
>> +  b1 = SCSCR_CKE1
>> +  b0 = SCSCR_CKE0
>
> What is that for exactly ?

What I can see from 3 different datasheets (sh7372, sh73a0, r8a7740)
the first 2 bits differ in meaning.

On r8a7740 it depends: In asynchronous mode the first 2 bits CKE0/1
define whether you want to use an external clock to drive the baud
generator or if you want to use the internal SUB clock. If you use the
SUB clock you can further define if you want to use a subscaled SUB
clock in the SCSMR register. In synchronous mode you must rely on the
internal clock for the baud generator and can select if the SCK pin is
used as clock input or output.

On sh73a0 and sh7372 it's used to control the output clock SCK (set it
to high impedance or actually output a clock when in sychronous mode)

Bit 2 and 3 don't exist in my datasheets.

The other bits define under which conditions you receive interrupts
(send FIFO empty, receive FIFO full) and which bits you need to start
transfers (one bit to start sending, one receiving). The bits 8 to 31
are used to set up DMA transfers and various interrupt events like
error status and finish transfers. I haven't included them as they are
not used in the driver.

Thanks,

Bastian