This is a note to let you know that I've just added the patch titled
serial: 8250: Add Nuvoton NPCM UART
to the 4.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-8250-add-nuvoton-npcm-uart.patch
and it can be found in the queue-4.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f597fbce38d230af95384f4a04e0a13a1d0ad45d Mon Sep 17 00:00:00 2001
From: Joel Stanley <joel@xxxxxxxxx>
Date: Mon, 5 Mar 2018 22:17:38 +1030
Subject: serial: 8250: Add Nuvoton NPCM UART
From: Joel Stanley <joel@xxxxxxxxx>
commit f597fbce38d230af95384f4a04e0a13a1d0ad45d upstream.
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@xxxxxxxxxx>
Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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(+)
--- 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.
--- 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_plat
{ .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);
--- 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 ua
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 +2153,15 @@ int serial8250_do_startup(struct uart_po
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 +2484,15 @@ static unsigned int xr17v35x_get_divisor
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 +2513,8 @@ static unsigned int serial8250_get_divis
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);
--- 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
Patches currently in stable-queue which might be from joel@xxxxxxxxx are
queue-4.16/serial-8250-add-nuvoton-npcm-uart.patch