Re: [PATCH v2 2/3] serial: 8250: introduce get_divisor() and set_divisor() hook

From: Andy Shevchenko
Date: Wed Jul 04 2018 - 06:01:03 EST


On Wed, 2018-07-04 at 17:02 +0800, Jisheng Zhang wrote:
> Add these two hooks so that they can be overridden with driver
> specific
> implementations.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

>
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@xxxxxxxxxxxxx>
> ---
> drivers/tty/serial/8250/8250_core.c | 4 ++++
> drivers/tty/serial/8250/8250_port.c | 27 +++++++++++++++++++++++----
> include/linux/serial_core.h | 7 +++++++
> 3 files changed, 34 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_core.c
> b/drivers/tty/serial/8250/8250_core.c
> index 9342fc2ee7df..a0bb77290747 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -1023,6 +1023,10 @@ int serial8250_register_8250_port(struct
> uart_8250_port *up)
> uart->port.get_mctrl = up->port.get_mctrl;
> if (up->port.set_mctrl)
> uart->port.set_mctrl = up->port.set_mctrl;
> + if (up->port.get_divisor)
> + uart->port.get_divisor = up-
> >port.get_divisor;
> + if (up->port.set_divisor)
> + uart->port.set_divisor = up-
> >port.set_divisor;
> if (up->port.startup)
> uart->port.startup = up->port.startup;
> if (up->port.shutdown)
> diff --git a/drivers/tty/serial/8250/8250_port.c
> b/drivers/tty/serial/8250/8250_port.c
> index 709fe6b4265c..ce0dc17f18ee 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -2498,9 +2498,9 @@ static unsigned int npcm_get_divisor(struct
> uart_8250_port *up,
> return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
> }
>
> -static unsigned int serial8250_get_divisor(struct uart_port *port,
> - unsigned int baud,
> - unsigned int *frac)
> +static unsigned int serial8250_do_get_divisor(struct uart_port *port,
> + unsigned int baud,
> + unsigned int *frac)
> {
> struct uart_8250_port *up = up_to_u8250p(port);
> unsigned int quot;
> @@ -2532,6 +2532,16 @@ static unsigned int
> serial8250_get_divisor(struct uart_port *port,
> return quot;
> }
>
> +static unsigned int serial8250_get_divisor(struct uart_port *port,
> + unsigned int baud,
> + unsigned int *frac)
> +{
> + if (port->get_divisor)
> + return port->get_divisor(port, baud, frac);
> +
> + return serial8250_do_get_divisor(port, baud, frac);
> +}
> +
> static unsigned char serial8250_compute_lcr(struct uart_8250_port
> *up,
> tcflag_t c_cflag)
> {
> @@ -2570,7 +2580,7 @@ static unsigned char
> serial8250_compute_lcr(struct uart_8250_port *up,
> return cval;
> }
>
> -static void serial8250_set_divisor(struct uart_port *port, unsigned
> int baud,
> +static void serial8250_do_set_divisor(struct uart_port *port,
> unsigned int baud,
> unsigned int quot, unsigned int
> quot_frac)
> {
> struct uart_8250_port *up = up_to_u8250p(port);
> @@ -2603,6 +2613,15 @@ static void serial8250_set_divisor(struct
> uart_port *port, unsigned int baud,
> }
> }
>
> +static void serial8250_set_divisor(struct uart_port *port, unsigned
> int baud,
> + unsigned int quot, unsigned int
> quot_frac)
> +{
> + if (port->set_divisor)
> + port->set_divisor(port, baud, quot, quot_frac);
> + else
> + serial8250_do_set_divisor(port, baud, quot,
> quot_frac);
> +}
> +
> static unsigned int serial8250_get_baud_rate(struct uart_port *port,
> struct ktermios
> *termios,
> struct ktermios *old)
> diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
> index 06ea4eeb09ab..406edae44ca3 100644
> --- a/include/linux/serial_core.h
> +++ b/include/linux/serial_core.h
> @@ -127,6 +127,13 @@ struct uart_port {
> struct ktermios *);
> unsigned int (*get_mctrl)(struct uart_port *);
> void (*set_mctrl)(struct uart_port *,
> unsigned int);
> + unsigned int (*get_divisor)(struct uart_port
> *,
> + unsigned int baud,
> + unsigned int *frac);
> + void (*set_divisor)(struct uart_port
> *,
> + unsigned int baud,
> + unsigned int quot,
> + unsigned int
> quot_frac);
> int (*startup)(struct uart_port
> *port);
> void (*shutdown)(struct uart_port
> *port);
> void (*throttle)(struct uart_port
> *port);

--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Intel Finland Oy