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Commit f597fbce authored by Joel Stanley's avatar Joel Stanley Committed by Greg Kroah-Hartman
Browse files

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: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarJoel Stanley <joel@jms.id.au>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ca7c22fc

Documentation/devicetree/bindings/serial/8250.txt

+1 −0
Original line number Diff line number Diff line
@@ -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.

drivers/tty/serial/8250/8250_of.c

+1 −0
Original line number Diff line number Diff line
@@ -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);

drivers/tty/serial/8250/8250_port.c

+33 −0
Original line number Diff line number Diff line
@@ -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);

include/uapi/linux/serial_core.h

+3 −0
Original line number Diff line number Diff line
@@ -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