1 files changed, 43 insertions, 0 deletions

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 555de07db593..2ab229ddee38 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -59,6 +59,8 @@ struct dw8250_data {
 	u8			usr_reg;
 	int			last_mcr;
 	int			line;
+	int			msr_mask_on;
+	int			msr_mask_off;
 	struct clk		*clk;
 	struct clk		*pclk;
 	struct reset_control	*rst;
@@ -81,6 +83,12 @@ static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value)
 		value &= ~UART_MSR_DCTS;
 	}
 
+	/* Override any modem control signals if needed */
+	if (offset == UART_MSR) {
+		value |= d->msr_mask_on;
+		value &= ~d->msr_mask_off;
+	}
+
 	return value;
 }
 
@@ -334,6 +342,30 @@ static int dw8250_probe_of(struct uart_port *p,
 	if (id >= 0)
 		p->line = id;
 
+	if (of_property_read_bool(np, "dcd-override")) {
+		/* Always report DCD as active */
+		data->msr_mask_on |= UART_MSR_DCD;
+		data->msr_mask_off |= UART_MSR_DDCD;
+	}
+
+	if (of_property_read_bool(np, "dsr-override")) {
+		/* Always report DSR as active */
+		data->msr_mask_on |= UART_MSR_DSR;
+		data->msr_mask_off |= UART_MSR_DDSR;
+	}
+
+	if (of_property_read_bool(np, "cts-override")) {
+		/* Always report DSR as active */
+		data->msr_mask_on |= UART_MSR_DSR;
+		data->msr_mask_off |= UART_MSR_DDSR;
+	}
+
+	if (of_property_read_bool(np, "ri-override")) {
+		/* Always report Ring indicator as inactive */
+		data->msr_mask_off |= UART_MSR_RI;
+		data->msr_mask_off |= UART_MSR_TERI;
+	}
+
 	/* clock got configured through clk api, all done */
 	if (p->uartclk)
 		return 0;
@@ -351,10 +383,20 @@ static int dw8250_probe_of(struct uart_port *p,
 static int dw8250_probe_acpi(struct uart_8250_port *up,
 			     struct dw8250_data *data)
 {
+	const struct acpi_device_id *id;
 	struct uart_port *p = &up->port;
 
 	dw8250_setup_port(up);
 
+	id = acpi_match_device(p->dev->driver->acpi_match_table, p->dev);
+	if (!id)
+		return -ENODEV;
+
+	if (!p->uartclk)
+		if (device_property_read_u32(p->dev, "clock-frequency",
+					     &p->uartclk))
+			return -EINVAL;
+
 	p->iotype = UPIO_MEM32;
 	p->serial_in = dw8250_serial_in32;
 	p->serial_out = dw8250_serial_out32;
@@ -577,6 +619,7 @@ static const struct acpi_device_id dw8250_acpi_match[] = {
 	{ "INT3435", 0 },
 	{ "80860F0A", 0 },
 	{ "8086228A", 0 },
+	{ "APMC0D08", 0},
 	{ },
 };
 MODULE_DEVICE_TABLE(acpi, dw8250_acpi_match);