cpm_uart: Modem control lines support
This patch replaces the get_mctrl/set_mctrl stubs with modem control line
read/write access through the GPIO lib.
Available modem control lines are described in the device tree using GPIO
bindings. The driver expect a GPIO pin for each of the CTS, RTS, DCD, DSR,
DTR and RI signals. Unused control lines can be left out.
Signed-off-by: Laurent Pinchart <laurentp@cse-semaphore.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
diff --git a/Documentation/powerpc/dts-bindings/fsl/cpm_qe/serial.txt b/Documentation/powerpc/dts-bindings/fsl/cpm_qe/serial.txt
index b35f348..2ea76d9 100644
--- a/Documentation/powerpc/dts-bindings/fsl/cpm_qe/serial.txt
+++ b/Documentation/powerpc/dts-bindings/fsl/cpm_qe/serial.txt
@@ -7,6 +7,15 @@
- fsl,cpm2-scc-uart
- fsl,qe-uart
+Modem control lines connected to GPIO controllers are listed in the gpios
+property as described in booting-without-of.txt, section IX.1 in the following
+order:
+
+CTS, RTS, DCD, DSR, DTR, and RI.
+
+The gpios property is optional and can be left out when control lines are
+not used.
+
Example:
serial@11a00 {
@@ -18,4 +27,6 @@
interrupt-parent = <&PIC>;
fsl,cpm-brg = <1>;
fsl,cpm-command = <00800000>;
+ gpios = <&gpio_c 15 0
+ &gpio_d 29 0>;
};
diff --git a/drivers/serial/cpm_uart/cpm_uart.h b/drivers/serial/cpm_uart/cpm_uart.h
index 5c76e0a..5999ef5 100644
--- a/drivers/serial/cpm_uart/cpm_uart.h
+++ b/drivers/serial/cpm_uart/cpm_uart.h
@@ -50,6 +50,15 @@
#define SCC_WAIT_CLOSING 100
+#define GPIO_CTS 0
+#define GPIO_RTS 1
+#define GPIO_DCD 2
+#define GPIO_DSR 3
+#define GPIO_DTR 4
+#define GPIO_RI 5
+
+#define NUM_GPIOS (GPIO_RI+1)
+
struct uart_cpm_port {
struct uart_port port;
u16 rx_nrfifos;
@@ -82,6 +91,7 @@
int wait_closing;
/* value to combine with opcode to form cpm command */
u32 command;
+ int gpios[NUM_GPIOS];
};
extern int cpm_uart_nr;
diff --git a/drivers/serial/cpm_uart/cpm_uart_core.c b/drivers/serial/cpm_uart/cpm_uart_core.c
index a4f8692..5e0c17f 100644
--- a/drivers/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/serial/cpm_uart/cpm_uart_core.c
@@ -43,6 +43,8 @@
#include <linux/dma-mapping.h>
#include <linux/fs_uart_pd.h>
#include <linux/of_platform.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
#include <asm/io.h>
#include <asm/irq.h>
@@ -96,13 +98,41 @@
static void cpm_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
- /* Whee. Do nothing. */
+ struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
+
+ if (pinfo->gpios[GPIO_RTS] >= 0)
+ gpio_set_value(pinfo->gpios[GPIO_RTS], !(mctrl & TIOCM_RTS));
+
+ if (pinfo->gpios[GPIO_DTR] >= 0)
+ gpio_set_value(pinfo->gpios[GPIO_DTR], !(mctrl & TIOCM_DTR));
}
static unsigned int cpm_uart_get_mctrl(struct uart_port *port)
{
- /* Whee. Do nothing. */
- return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
+ struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
+ unsigned int mctrl = TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+
+ if (pinfo->gpios[GPIO_CTS] >= 0) {
+ if (gpio_get_value(pinfo->gpios[GPIO_CTS]))
+ mctrl &= ~TIOCM_CTS;
+ }
+
+ if (pinfo->gpios[GPIO_DSR] >= 0) {
+ if (gpio_get_value(pinfo->gpios[GPIO_DSR]))
+ mctrl &= ~TIOCM_DSR;
+ }
+
+ if (pinfo->gpios[GPIO_DCD] >= 0) {
+ if (gpio_get_value(pinfo->gpios[GPIO_DCD]))
+ mctrl &= ~TIOCM_CAR;
+ }
+
+ if (pinfo->gpios[GPIO_RI] >= 0) {
+ if (!gpio_get_value(pinfo->gpios[GPIO_RI]))
+ mctrl |= TIOCM_RNG;
+ }
+
+ return mctrl;
}
/*
@@ -991,6 +1021,7 @@
void __iomem *mem, *pram;
int len;
int ret;
+ int i;
data = of_get_property(np, "fsl,cpm-brg", &len);
if (!data || len != 4) {
@@ -1050,6 +1081,9 @@
goto out_pram;
}
+ for (i = 0; i < NUM_GPIOS; i++)
+ pinfo->gpios[i] = of_get_gpio(np, i);
+
return cpm_uart_request_port(&pinfo->port);
out_pram: