From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH] tty: serial: don't do termios for BTIF Date: Thu, 13 Dec 2018 11:00:29 +0000 Message-ID: <20181213110029.GN30658@n2100.armlinux.org.uk> References: <972976519be8e28ee600651fe14d1f6d5f23e697.1544679557.git.ryder.lee@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <972976519be8e28ee600651fe14d1f6d5f23e697.1544679557.git.ryder.lee@mediatek.com> Sender: linux-kernel-owner@vger.kernel.org To: Ryder Lee Cc: Andy Shevchenko , Greg Kroah-Hartman , Sean Wang , Sean Wang , Weijie Gao , linux-kernel@vger.kernel.org, Roy Luo , linux-mediatek@lists.infradead.org, linux-serial@vger.kernel.org, Matthias Brugger , linux-arm-kernel@lists.infradead.org List-Id: linux-serial@vger.kernel.org On Thu, Dec 13, 2018 at 02:24:03PM +0800, Ryder Lee wrote: > The MediaTek BTIF controller doesn't need to set termios so add > a new capability 'UART_CAP_NMOD' for the unsupported case. > > > Signed-off-by: Sean Wang > Signed-off-by: Ryder Lee > --- > drivers/tty/serial/8250/8250.h | 1 + > drivers/tty/serial/8250/8250_port.c | 7 ++++++- > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h > index ebfb0bd..2b9ba39 100644 > --- a/drivers/tty/serial/8250/8250.h > +++ b/drivers/tty/serial/8250/8250.h > @@ -80,6 +80,7 @@ struct serial8250_config { > #define UART_CAP_MINI (1 << 17) /* Mini UART on BCM283X family lacks: > * STOP PARITY EPAR SPAR WLEN5 WLEN6 > */ > +#define UART_CAP_NMOD (1 << 18) /* UART doesn't do termios */ > > #define UART_BUG_QUOT (1 << 0) /* UART has buggy quot LSB */ > #define UART_BUG_TXEN (1 << 1) /* UART has buggy TX IIR status */ > diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c > index c39482b..e4a69a0 100644 > --- a/drivers/tty/serial/8250/8250_port.c > +++ b/drivers/tty/serial/8250/8250_port.c > @@ -297,7 +297,7 @@ > .tx_loadsz = 16, > .fcr = UART_FCR_ENABLE_FIFO | > UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT, > - .flags = UART_CAP_FIFO, > + .flags = UART_CAP_FIFO | UART_CAP_NMOD, > }, > [PORT_NPCM] = { > .name = "Nuvoton 16550", > @@ -2663,6 +2663,11 @@ static unsigned int serial8250_get_baud_rate(struct uart_port *port, > unsigned long flags; > unsigned int baud, quot, frac = 0; > > + if (up->capabilities & UART_CAP_NMOD) { > + termios->c_cflag = 0; So your port is limited to 5-bits and is unable to receive characters? That's what a zero cflag means, and that's what you'll be telling userspace here. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up