Messages in this thread | | | Subject | Re: [PATCH 4/8] serial: 8250: Handle case port doesn't have TEMT interrupt using em485. | From | Giulio Benetti <> | Date | Mon, 4 Jun 2018 12:50:44 +0200 |
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Hi,
Il 04/06/2018 12:17, Andy Shevchenko ha scritto: > On Fri, 2018-06-01 at 14:40 +0200, Giulio Benetti wrote: >> Some 8250 ports only have TEMT interrupt, so current implementation >> can't work for ports without it. The only chance to make it work is to >> loop-read on LSR register. >> >> With NO TEMT interrupt check if both TEMT and THRE are set looping on >> LSR register. > >> --- a/drivers/tty/serial/8250/8250_dw.c >> +++ b/drivers/tty/serial/8250/8250_dw.c > >> - int ret = serial8250_em485_init(up); >> + int ret = serial8250_em485_init(up, false); > > Is true for all possible DW configured types? Or it's your particular > case? >
I've checked on Synopsis Designware 8250 datasheet and it's not supported. Here is datasheet I went through: https://linux-sunxi.org/images/d/d2/Dw_apb_uart_db.pdf
There seems not to be TEMT interrupt, I use it under sunxi SoC and on their datasheet(A20 for example), they don't report that interrupt too. So it seems to be valid for all DW configured types, anyway I don't know how many IP reviews there could be of that peripheral. I've tried to subscribe at Synopsis to obtain latest Datasheet but it ask me an active ID I don't have.
-- Giulio Benetti CTO
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