[PATCH 2/3] serial: 8250: Add new port type for TI DA8xx/OMAPL13x/AM17xx/AM18xx

David Lechner
2016-12-20T20:23:29Z

This adds a new UART port type for TI DA8xx/OMAPL13x/AM17xx/AM18xx. These
SoCs have standard 8250 registers plus some extra non-standard registers.

The UART will not function unless the non-standard Power and Emulation
Management Register (PWREMU_MGMT) is configured correctly. This is
currently handled in arch/arm/mach-davinci/serial.c for non-device-tree
boards. Making this part of the UART driver will allow UART to work on
device-tree boards as well and the mach code can eventually be removed.

Signed-off-by: David Lechner <david@lechnology.com>
---
drivers/tty/serial/8250/8250_of.c | 1 +
drivers/tty/serial/8250/8250_port.c | 22 ++++++++++++++++++++++
include/uapi/linux/serial_core.h | 3 ++-
include/uapi/linux/serial_reg.h | 8 ++++++++
4 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c
index d25ab1c..5281252 100644
--- a/drivers/tty/serial/8250/8250_of.c
+++ b/drivers/tty/serial/8250/8250_of.c
@@ -332,6 +332,7 @@ static const struct of_device_id of_platform_serial_table[] = {
.data = (void *)PORT_ALTR_16550_F128, },
{ .compatible = "mrvl,mmp-uart",
.data = (void *)PORT_XSCALE, },
+ { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
{ /* 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 fe4399b..ea854054 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -273,6 +273,15 @@ static const struct serial8250_config uart_config[] = {
.rxtrig_bytes = {1, 4, 8, 14},
.flags = UART_CAP_FIFO,
},
+ [PORT_DA830] = {
+ .name = "TI DA8xx/OMAPL13x/AM17xx/AM18xx",
+ .fifo_size = 16,
+ .tx_loadsz = 16,
+ .fcr = UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
+ UART_FCR_R_TRIG_10,
+ .rxtrig_bytes = {1, 4, 8, 14},
+ .flags = UART_CAP_FIFO | UART_CAP_AFE,
+ },
};

/* Uart divisor latch read */
@@ -2118,6 +2127,19 @@ int serial8250_do_startup(struct uart_port *port)
serial_port_out(port, UART_LCR, 0);
}

+ if (port->type == PORT_DA830) {
+ /* Reset the port */
+ serial_port_out(port, UART_IER, 0);
+ serial_port_out(port, UART_DA830_PWREMU_MGMT, 0);
+ mdelay(10);
+
+ /* Enable Tx, Rx and free run mode */
+ serial_port_out(port, UART_DA830_PWREMU_MGMT,
+ UART_DA830_PWREMU_MGMT_UTRST |
+ UART_DA830_PWREMU_MGMT_URRST |
+ UART_DA830_PWREMU_MGMT_FREE);
+ }
+
#ifdef CONFIG_SERIAL_8250_RSA
/*
* If this is an RSA port, see if we can kick it up to the
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index 99dbed8..a126d05 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -56,7 +56,8 @@
#define PORT_ALTR_16550_F128 28 /* Altera 16550 UART with 128 FIFOs */
#define PORT_RT2880 29 /* Ralink RT2880 internal UART */
#define PORT_16550A_FSL64 30 /* Freescale 16550 UART with 64 FIFOs */
-#define PORT_MAX_8250 30 /* max port ID */
+#define PORT_DA830 31 /* TI DA8xx/OMAP13x/AM17xx/AM18xx */
+#define PORT_MAX_8250 31 /* max port ID */

/*
* ARM specific type numbers. These are not currently guaranteed
diff --git a/include/uapi/linux/serial_reg.h b/include/uapi/linux/serial_reg.h
index b4c0484..0e72eeb 100644
--- a/include/uapi/linux/serial_reg.h
+++ b/include/uapi/linux/serial_reg.h
@@ -327,6 +327,14 @@
#define SERIAL_RSA_BAUD_BASE (921600)
#define SERIAL_RSA_BAUD_BASE_LO (SERIAL_RSA_BAUD_BASE / 8)

+/* Extra registers for TI DA8xx/OMAP13x/AM17xx/AM18xx */
+#define UART_DA830_PWREMU_MGMT 12
+
+/* PWREMU_MGMT register bits */
+#define UART_DA830_PWREMU_MGMT_FREE (1 << 0) /* Free-running mode */
+#define UART_DA830_PWREMU_MGMT_URRST (1 << 13) /* Receiver reset/enable */
+#define UART_DA830_PWREMU_MGMT_UTRST (1 << 14) /* Transmitter reset/enable */
+
/*
* Extra serial register definitions for the internal UARTs
* in TI OMAP processors.
--
2.7.4