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 <[email protected]>
---
Documentation/devicetree/bindings/serial/8250.txt | 1 +
drivers/tty/serial/8250/8250_of.c | 1 +
drivers/tty/serial/8250/8250_port.c | 30 +++++++++++++++++++++++
include/uapi/linux/serial_core.h | 3 +++
include/uapi/linux/serial_reg.h | 5 ++++
5 files changed, 40 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..c2e7fc111338 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -293,6 +293,16 @@ 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 +2150,15 @@ 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 +2481,15 @@ 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 +2510,8 @@ 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..3890ca4c5985 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -278,4 +278,7 @@
/* MediaTek BTIF */
#define PORT_MTK_BTIF 117
+/* Nuvoton UART */
+#define PORT_NPCM 118
+
#endif /* _UAPILINUX_SERIAL_CORE_H */
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 */
+
#endif /* _LINUX_SERIAL_REG_H */
--
2.15.1
On Mon, Feb 12, 2018 at 6:48 AM, Joel Stanley <[email protected]> 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.
> + [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,
> +
Redundant.
> + },
> + /*
> + * 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);
> +/* Nuvoton NPCM UARTs have a custom divisor calculation */
> + return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
Is there any link to datasheet?
> +/* Nuvoton UART */
> +#define PORT_NPCM 118
We have gaps there. #40 is perfect place for this one.
> +/* Nuvoton NPCM timeout register */
> +#define UART_NPCM_TOR 7
> +#define UART_NPCM_TOIE BIT(7) /* Timeout Interrupt Enable */
--
With Best Regards,
Andy Shevchenko
On Wed, Feb 14, 2018 at 3:22 AM, Andy Shevchenko
<[email protected]> wrote:
> On Mon, Feb 12, 2018 at 6:48 AM, Joel Stanley <[email protected]> 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.
>
>
>> + [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,
>
>> +
>
> Redundant.
You are referring to the extra whitespace?
>> + },
>
>> + /*
>> + * 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);
>
>> +/* Nuvoton NPCM UARTs have a custom divisor calculation */
>> + return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
>
> Is there any link to datasheet?
I have a copy of the datasheet under NDA. The Nuvoton guys might be
able to help you out. Avi?
>
>> +/* Nuvoton UART */
>> +#define PORT_NPCM 118
>
> We have gaps there. #40 is perfect place for this one.
Ok, I will move it up. Thanks for the review.
Cheers,
Joel
> From: [email protected] [mailto:[email protected]] On Behalf Of Joel Stanley
> Sent: Thursday, February 15, 2018 4:00 AM
>
> On Wed, Feb 14, 2018 at 3:22 AM, Andy Shevchenko <[email protected]> wrote:
>> On Mon, Feb 12, 2018 at 6:48 AM, Joel Stanley <[email protected]> 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.
>>
>>
>>> + [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,
>>
>>> +
>>
>> Redundant.
>
> You are referring to the extra whitespace?
>
>>> + },
>>
>>> + /*
>>> + * 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);
>>
>>> +/* Nuvoton NPCM UARTs have a custom divisor calculation */
>>> + return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
>>
>> Is there any link to datasheet?
>
> I have a copy of the datasheet under NDA. The Nuvoton guys might be able to help you out. Avi?
In the spec the calculation is as follows:
BaudOut = Selected UART Clock Source / ( 16 * [Divisor + 2] )
To translate it to our code is:
baud = port->uartclk / (16 * (Divisor + 2) )
So it should calculate without the "+ 2" inside as follow:
+ return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud) - 2;
In order to get the spec you can add somthing like that:
"For getting the NPCM7XX Data Sheet please contact [email protected]".
BTW Andy, Intel has our Data Sheet under NDA, you can ask Mihm James
<[email protected]>.
>
>>
>>> +/* Nuvoton UART */
>>> +#define PORT_NPCM 118
>>
>> We have gaps there. #40 is perfect place for this one.
>
> Ok, I will move it up. Thanks for the review.
>
> Cheers,
>
> Joel
>