From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753332AbbKGMkO (ORCPT ); Sat, 7 Nov 2015 07:40:14 -0500 Received: from mail-wm0-f42.google.com ([74.125.82.42]:35969 "EHLO mail-wm0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752085AbbKGMkL (ORCPT ); Sat, 7 Nov 2015 07:40:11 -0500 MIME-Version: 1.0 In-Reply-To: <563DED05.9010004@hurleysoftware.com> References: <1446890976-1817-1-git-send-email-matwey@sai.msu.ru> <563DED05.9010004@hurleysoftware.com> From: "Matwey V. Kornilov" Date: Sat, 7 Nov 2015 15:39:50 +0300 X-Google-Sender-Auth: WRZ1Ve8DVvJefpRJt0bEOLcWt5c Message-ID: Subject: Re: [PATCH v2 1/3] tty: Introduce UART_CAP_HW485 To: Peter Hurley Cc: Greg KH , jslaby@suse.com, linux-serial@vger.kernel.org, linux-kernel Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2015-11-07 15:22 GMT+03:00 Peter Hurley : > On 11/07/2015 05:09 AM, Matwey V. Kornilov wrote: >> Introduce new capability UART_CAP_HW485 to mark 8250 UARTs which have >> hardware support of line direction control. > > Since capabilities are not exported to user-space, how will user-space > know if the port only provides emulated 485 (eg., where only HW485 is > acceptable)? I cannot imagine the case when user really has to care about implementation details. In both cases the user will be provided with the consistent API (TIOCGRS485/TIOCSRS485 ioctls) resulting into the same behavior. Could you please expand your question? > > Regards, > Peter Hurley > >> Signed-off-by: Matwey V. Kornilov >> --- >> Changes since v1: >> - Commit message has been wrapped >> >> drivers/tty/serial/8250/8250.h | 1 + >> drivers/tty/serial/8250/8250_fintek.c | 1 + >> drivers/tty/serial/8250/8250_lpc18xx.c | 1 + >> drivers/tty/serial/8250/8250_pci.c | 1 + >> 4 files changed, 4 insertions(+) >> >> diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h >> index d54dcd8..92a4f47 100644 >> --- a/drivers/tty/serial/8250/8250.h >> +++ b/drivers/tty/serial/8250/8250.h >> @@ -69,6 +69,7 @@ struct serial8250_config { >> unsigned int flags; >> }; >> >> +#define UART_CAP_HW485 (1 << 7) /* UART has hardware direction control for RS485 */ >> #define UART_CAP_FIFO (1 << 8) /* UART has FIFO */ >> #define UART_CAP_EFR (1 << 9) /* UART has EFR */ >> #define UART_CAP_SLEEP (1 << 10) /* UART has IER sleep */ >> diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c >> index 8947439..f2831a8 100644 >> --- a/drivers/tty/serial/8250/8250_fintek.c >> +++ b/drivers/tty/serial/8250/8250_fintek.c >> @@ -208,6 +208,7 @@ fintek_8250_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id) >> uart.port.iobase = pnp_port_start(dev, 0); >> uart.port.iotype = UPIO_PORT; >> uart.port.rs485_config = fintek_8250_rs485_config; >> + uart.capabilities = UART_CAP_HW485; >> >> uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF; >> if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE) >> diff --git a/drivers/tty/serial/8250/8250_lpc18xx.c b/drivers/tty/serial/8250/8250_lpc18xx.c >> index 99cd478..9d30276 100644 >> --- a/drivers/tty/serial/8250/8250_lpc18xx.c >> +++ b/drivers/tty/serial/8250/8250_lpc18xx.c >> @@ -175,6 +175,7 @@ static int lpc18xx_serial_probe(struct platform_device *pdev) >> uart.port.private_data = data; >> uart.port.rs485_config = lpc18xx_rs485_config; >> uart.port.serial_out = lpc18xx_uart_serial_out; >> + uart.capabilities = UART_CAP_HW485; >> >> uart.dma = &data->dma; >> uart.dma->rxconf.src_maxburst = 1; >> diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c >> index 4097f3f..c7c0ae9 100644 >> --- a/drivers/tty/serial/8250/8250_pci.c >> +++ b/drivers/tty/serial/8250/8250_pci.c >> @@ -1599,6 +1599,7 @@ static int pci_fintek_setup(struct serial_private *priv, >> port->port.iotype = UPIO_PORT; >> port->port.iobase = iobase; >> port->port.rs485_config = pci_fintek_rs485_config; >> + port->capabilities = UART_CAP_HW485; >> >> data = devm_kzalloc(&pdev->dev, sizeof(u8), GFP_KERNEL); >> if (!data) >> > -- With best regards, Matwey V. Kornilov. Sternberg Astronomical Institute, Lomonosov Moscow State University, Russia 119991, Moscow, Universitetsky pr-k 13, +7 (495) 9392382