On Wed, Sep 28, 2022 at 02:38:40PM +0300, Ilpo Järvinen wrote: > On Tue, 27 Sep 2022, Lukas Wunner wrote: > > Recent TI Sitara SoCs such as AM64/AM65 have gained the ability to > > automatically assert RTS when data is transmitted, obviating the need > > to emulate this functionality in software. > > > > The feature is controlled through new DIR_EN and DIR_POL bits in the > > Mode Definition Register 3. For details see page 8783 and 8890 of the > > AM65 TRM: https://www.ti.com/lit/ug/spruid7e/spruid7e.pdf [...] > > @@ -1335,10 +1387,7 @@ static int omap8250_probe(struct platform_device *pdev) > > up.port.shutdown = omap_8250_shutdown; > > up.port.throttle = omap_8250_throttle; > > up.port.unthrottle = omap_8250_unthrottle; > > - up.port.rs485_config = serial8250_em485_config; > > up.port.rs485_supported = serial8250_em485_supported; > > - up.rs485_start_tx = serial8250_em485_start_tx; > > - up.rs485_stop_tx = serial8250_em485_stop_tx; > > up.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE); > > > > ret = of_alias_get_id(np, "serial"); > > @@ -1377,6 +1426,14 @@ static int omap8250_probe(struct platform_device *pdev) > > DEFAULT_CLK_SPEED); > > } > > > > + if (priv->habit & UART_HAS_NATIVE_RS485) { > > + up.port.rs485_config = omap8250_rs485_config; > > + } else { > > + up.port.rs485_config = serial8250_em485_config; > > + up.rs485_start_tx = serial8250_em485_start_tx; > > + up.rs485_stop_tx = serial8250_em485_stop_tx; > > + } > > I guess .rs485_supported shouldn't be equal in both cases? I contemplated whether it should be different for hardware-assisted RS485 but came to the conclusion that it shouldn't: The polarity may be chosen both for hardware- and software-controlled RTS. Whether RX_DURING_TX is possible depends on how the RS485 transceiver is wired to the UART: If RTS asserts !RE on the transceiver when sending, the UART cannot receive data, regardless whether hardware- or software- controlled RTS is used. TERMINATE_BUS works independently from RTS control. And ADDRB doesn't seem to be supported in either mode AFAICS. Am I missing something? Thanks, Lukas
