This is a note to let you know that I've just added the patch titled

serial: 8250: Add Nuvoton NPCM UART

to my tty git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git in the tty-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the tty-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From f597fbce38d230af95384f4a04e0a13a1d0ad45d Mon Sep 17 00:00:00 2001

From: Joel Stanley joel@jms.id.au Date: Mon, 5 Mar 2018 22:17:38 +1030 Subject: serial: 8250: Add Nuvoton NPCM UART

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.

Reviewed-by: Rob Herring robh@kernel.org Signed-off-by: Joel Stanley joel@jms.id.au Cc: stable stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Documentation/devicetree/bindings/serial/8250.txt | 1 + drivers/tty/serial/8250/8250_of.c | 1 + drivers/tty/serial/8250/8250_port.c | 33 +++++++++++++++++++++++ include/uapi/linux/serial_core.h | 3 +++ 4 files changed, 38 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 ffbb955d1c06..95833cbc4338 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -47,6 +47,10 @@ #define UART_EXAR_SLEEP 0x8b /* Sleep mode */ #define UART_EXAR_DVID 0x8d /* Device identification */

+/* Nuvoton NPCM timeout register */ +#define UART_NPCM_TOR 7 +#define UART_NPCM_TOIE BIT(7) /* Timeout Interrupt Enable */ + /* * Debugging. */ @@ -293,6 +297,15 @@ 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 */ @@ -2141,6 +2154,15 @@ 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 @@ -2463,6 +2485,15 @@ 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) @@ -2483,6 +2514,8 @@ 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