On Mon, Jun 06, 2022 at 01:04:19PM +0300, Ilpo Järvinen wrote: > - if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) { > + if (!port->rs485_supported->delay_rts_before_send) { > + if (rs485->delay_rts_before_send) { > + dev_warn_ratelimited(port->dev, > + "%s (%d): RTS delay before sending not supported\n", > + port->name, port->line); > + } > + rs485->delay_rts_before_send = 0; > + } else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) { > rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY; > dev_warn_ratelimited(port->dev, > "%s (%d): RTS delay before sending clamped to %u ms\n", > port->name, port->line, rs485->delay_rts_before_send); > } This series seems to set rs485_supported->delay_rts_before_send to 1 in all drivers to indicate that a delay is supported. It would probably be smarter to define it as a maximum, i.e. drivers declare the supported maximum delay in their rs485_supported struct and the core can use that to clamp the value. Initially, all drivers may use RS485_MAX_RTS_DELAY. Some chips only support specific delays (multiples of the UART clock or baud clock). We can amend their drivers later according to their capabilities. Thanks, Lukas