From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bhuvanchandra DV Subject: Re: [PATCH 3/3] tty: serial: fsl_lpuart: Add support for RS-485 Date: Fri, 29 May 2015 16:12:13 +0530 Message-ID: <55684285.4000004@toradex.com> References: <1432886754-30115-1-git-send-email-bhuvanchandra.dv@toradex.com> <1432886754-30115-4-git-send-email-bhuvanchandra.dv@toradex.com> <20150529121808.27346afc@north> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150529121808.27346afc@north> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: =?UTF-8?B?SmFrdWIgS2ljacWEc2tp?= Cc: gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, stefan-XLVq0VzYD2Y@public.gmane.org, shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, jslaby-AlSwsSmVLrQ@public.gmane.org, linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, bhuvanchandra.dv-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org List-Id: devicetree@vger.kernel.org On 05/29/2015 03:48 PM, Jakub Kici=C5=84ski wrote: > On Fri, 29 May 2015 13:35:54 +0530, Bhuvanchandra DV wrote: >> Enable Vybrid's build-in support for RS-485 auto RTS for >> controlling line direction of RS-485 transceiver driver. >> >> Signed-off-by: Bhuvanchandra DV >> --- >> drivers/tty/serial/fsl_lpuart.c | 60 +++++++++++++++++++++++++++++= ++++++++++++ >> 1 file changed, 60 insertions(+) >> >> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fs= l_lpuart.c >> index 357f623..c553b14 100644 >> --- a/drivers/tty/serial/fsl_lpuart.c >> +++ b/drivers/tty/serial/fsl_lpuart.c >> @@ -820,6 +820,50 @@ static unsigned int lpuart32_tx_empty(struct ua= rt_port *port) >> TIOCSER_TEMT : 0; >> } >> >> +static int lpuart_config_rs485(struct uart_port *port, >> + struct serial_rs485 *rs485) >> +{ >> + struct lpuart_port *sport =3D container_of(port, >> + struct lpuart_port, port); >> + u8 modem =3D readb(sport->port.membase + UARTMODEM) & >> + ~(UARTMODEM_TXRTSPOL | UARTMODEM_TXRTSE); > > Please put empty line between variables and code. Ok > >> + writeb(modem, sport->port.membase + UARTMODEM); >> + >> + if (rs485->flags & SER_RS485_ENABLED) { >> + /* Enable auto RS-485 RTS mode */ >> + modem |=3D UARTMODEM_TXRTSE; >> + >> + /* >> + * RTS needs to be logic HIGH either during transer _or_ after >> + * transfer, other variants are not supported by the hardware. >> + */ > > Indentation is off here. '*' should be aligned. Ok > >> + if (!(rs485->flags & (SER_RS485_RTS_ON_SEND | >> + SER_RS485_RTS_AFTER_SEND))) > > and here - things should be aligned on the containing bracket (SER_ > under SER_ here). Ok > >> + rs485->flags |=3D SER_RS485_RTS_ON_SEND; >> + >> + if (rs485->flags & SER_RS485_RTS_ON_SEND && >> + rs485->flags & SER_RS485_RTS_AFTER_SEND) > > and here - same bracket rule (rs485-> under rs485->) Ok > >> + rs485->flags &=3D ~SER_RS485_RTS_AFTER_SEND; >> + >> + /* >> + * The hardware defaults to RTS logic HIGH while transfer. >> + * Switch polarity in case RTS shall be logic HIGH >> + * after transfer. >> + * Note: UART is assumed to be active high. >> + */ >> + if (rs485->flags & SER_RS485_RTS_ON_SEND) >> + modem &=3D ~UARTMODEM_TXRTSPOL; > > UARTMODEM_TXRTSPOL was already clear when you read modem. Ok > >> + else if (rs485->flags & SER_RS485_RTS_AFTER_SEND) >> + modem |=3D UARTMODEM_TXRTSPOL; >> + } >> + >> + /* Store the new configuration */ >> + sport->port.rs485 =3D *rs485; >> + >> + writeb(modem, sport->port.membase + UARTMODEM); >> + return 0; >> +} >> + >> static unsigned int lpuart_get_mctrl(struct uart_port *port) >> { >> return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR; > [...] >> @@ -1802,6 +1854,14 @@ static int lpuart_probe(struct platform_devic= e *pdev) >> dev_info(sport->port.dev, "DMA rx channel request failed, " >> "operating without rx DMA\n"); >> >> + if (of_property_read_bool(np, "linux,rs485-enabled-at-boot-time"))= { >> + sport->port.rs485.flags |=3D SER_RS485_ENABLED; >> + sport->port.rs485.flags |=3D SER_RS485_RTS_ON_SEND; >> + writeb(UARTMODEM_TXRTSE, sport->port.membase + UARTMODEM); >> + } else { >> + sport->port.rs485.flags &=3D ~SER_RS485_ENABLED; > > Why the need to clear the flag? sport was kzalloc'ed. Will remove it. > Best Regards, Bhuvan -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html