On Thu, Feb 15, 2018 at 12:47:20PM +1030, Joel Stanley wrote:
> The Nuvoton UART is almost compatible with the 8250 driver when probed
> via the 8250_of driver, however it requires some extra configuration
> at startup.
>
> Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
> Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
> ---
> v2:
> Remove redundant whitespace
> Use port number 40 to fill in a gap
>
> Documentation/devicetree/bindings/serial/8250.txt | 1 +
> drivers/tty/serial/8250/8250_of.c | 1 +
> drivers/tty/serial/8250/8250_port.c | 29 +++++++++++++++++++++++
> include/uapi/linux/serial_core.h | 3 +++
> include/uapi/linux/serial_reg.h | 5 ++++
> 5 files changed, 39 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/serial/8250.txt b/Documentation/devicetree/bindings/serial/8250.txt
> index dad3b2ec66d4..aeb6db4e35c3 100644
> --- a/Documentation/devicetree/bindings/serial/8250.txt
> +++ b/Documentation/devicetree/bindings/serial/8250.txt
> @@ -24,6 +24,7 @@ Required properties:
> - "ti,da830-uart"
> - "aspeed,ast2400-vuart"
> - "aspeed,ast2500-vuart"
> + - "nuvoton,npcm750-uart"
> - "serial" if the port type is unknown.
> - reg : offset and length of the register set for the device.
> - interrupts : should contain uart interrupt.
> diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c
> index 160b8906d9b9..9835b1c1cbe1 100644
> --- a/drivers/tty/serial/8250/8250_of.c
> +++ b/drivers/tty/serial/8250/8250_of.c
> @@ -316,6 +316,7 @@ static const struct of_device_id of_platform_serial_table[] = {
> { .compatible = "mrvl,mmp-uart",
> .data = (void *)PORT_XSCALE, },
> { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
> + { .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
> { /* end of list */ },
> };
> MODULE_DEVICE_TABLE(of, of_platform_serial_table);
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index 1328c7e70108..a72222f8b005 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -293,6 +293,15 @@ static const struct serial8250_config uart_config[] = {
> UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
> .flags = UART_CAP_FIFO,
> },
> + [PORT_NPCM] = {
> + .name = "Nuvoton 16550",
> + .fifo_size = 16,
> + .tx_loadsz = 16,
> + .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
> + UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
> + .rxtrig_bytes = {1, 4, 8, 14},
> + .flags = UART_CAP_FIFO,
> + },
> };
>
> /* Uart divisor latch read */
> @@ -2140,6 +2149,15 @@ int serial8250_do_startup(struct uart_port *port)
> UART_DA830_PWREMU_MGMT_FREE);
> }
>
> + if (port->type == PORT_NPCM) {
> + /*
> + * Nuvoton calls the scratch register 'UART_TOR' (timeout
> + * register). Enable it, and set TIOC (timeout interrupt
> + * comparator) to be 0x20 for correct operation.
> + */
> + serial_port_out(port, UART_NPCM_TOR, UART_NPCM_TOIE | 0x20);
> + }
> +
> #ifdef CONFIG_SERIAL_8250_RSA
> /*
> * If this is an RSA port, see if we can kick it up to the
> @@ -2462,6 +2480,15 @@ static unsigned int xr17v35x_get_divisor(struct uart_8250_port *up,
> return quot_16 >> 4;
> }
>
> +/* Nuvoton NPCM UARTs have a custom divisor calculation */
> +static unsigned int npcm_get_divisor(struct uart_8250_port *up,
> + unsigned int baud)
> +{
> + struct uart_port *port = &up->port;
> +
> + return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
> +}
> +
> static unsigned int serial8250_get_divisor(struct uart_8250_port *up,
> unsigned int baud,
> unsigned int *frac)
> @@ -2482,6 +2509,8 @@ static unsigned int serial8250_get_divisor(struct uart_8250_port *up,
> quot = 0x8002;
> else if (up->port.type == PORT_XR17V35X)
> quot = xr17v35x_get_divisor(up, baud, frac);
> + else if (up->port.type == PORT_NPCM)
> + quot = npcm_get_divisor(up, baud);
> else
> quot = uart_get_divisor(port, baud);
>
> diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
> index 1c8413f93e3d..dce5f9dae121 100644
> --- a/include/uapi/linux/serial_core.h
> +++ b/include/uapi/linux/serial_core.h
> @@ -76,6 +76,9 @@
> #define PORT_SUNZILOG 38
> #define PORT_SUNSAB 39
>
> +/* Nuvoton UART */
> +#define PORT_NPCM 40
> +
> /* Intel EG20 */
> #define PORT_PCH_8LINE 44
> #define PORT_PCH_2LINE 45
> diff --git a/include/uapi/linux/serial_reg.h b/include/uapi/linux/serial_reg.h
> index be07b5470f4b..f82f3c869df9 100644
> --- a/include/uapi/linux/serial_reg.h
> +++ b/include/uapi/linux/serial_reg.h
> @@ -376,5 +376,10 @@
> #define UART_ALTR_EN_TXFIFO_LW 0x01 /* Enable the TX FIFO Low Watermark */
> #define UART_ALTR_TX_LOW 0x41 /* Tx FIFO Low Watermark */
>
> +
> +/* Nuvoton NPCM timeout register */
> +#define UART_NPCM_TOR 7
> +#define UART_NPCM_TOIE BIT(7) /* Timeout Interrupt Enable */
Why is this needed in a userspace api file? That feels very odd for
just a new device. Please put this somewhere internal.
thanks,
greg k-h
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