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    SubjectRe: [PATCH v2] tty: make pl011 serial port driver support 485 mode
    On Thu, Jan 07, 2021 at 02:16:41PM +0800, zhangqiumiao1@huawei.com wrote:
    > From: Qiumiao Zhang <zhangqiumiao1@huawei.com>
    >
    > make pl011 serial port support 485 mode full duplex communication
    >
    > Signed-off-by: Qiumiao Zhang <zhangqiumiao1@huawei.com>
    > ---
    > Changes in v2:
    > - Fix two compilation errors

    What changed from the version you sent yesterday with this same subject
    line?

    > drivers/tty/serial/amba-pl011.c | 38 +++++++++++++++++++++++++++++++++
    > 1 file changed, 38 insertions(+)
    >
    > diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
    > index c255476cce28..f6a7fe61e699 100644
    > --- a/drivers/tty/serial/amba-pl011.c
    > +++ b/drivers/tty/serial/amba-pl011.c
    > @@ -44,6 +44,7 @@
    >
    > #include "amba-pl011.h"
    >
    > +#define ISEMPTY 1
    > #define UART_NR 14
    >
    > #define SERIAL_AMBA_MAJOR 204
    > @@ -1284,14 +1285,33 @@ static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
    > #define pl011_dma_flush_buffer NULL
    > #endif
    >
    > +static unsigned int pl011_tx_empty(struct uart_port *port);
    > +
    > static void pl011_stop_tx(struct uart_port *port)
    > {
    > + unsigned int cr;
    > + unsigned int result;

    But below the uap definition please, like kernel style normally is.

    > struct uart_amba_port *uap =
    > container_of(port, struct uart_amba_port, port);
    >
    > uap->im &= ~UART011_TXIM;
    > pl011_write(uap->im, uap, REG_IMSC);
    > pl011_dma_tx_stop(uap);
    > + if (port->rs485.flags & SER_RS485_ENABLED) {
    > + while(1) {
    > + result = pl011_tx_empty(port);
    > + if (ISEMPTY == result) {
    > + break;
    > + }

    It's not ok to busy loop forever, sorry.

    > + }
    > + cr = pl011_read(uap, REG_CR);
    > + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) {
    > + cr |= UART011_CR_RTS;
    > + } else {
    > + cr &= ~UART011_CR_RTS;
    > + }

    Did you run checkpatch on this code? Please fix up.

    thanks,

    greg k-h

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