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Subject[PATCH 06/25] serial: bfin_sport_uart: add support for CTS/RTS via GPIOs
Date
From: Sonic Zhang <sonic.zhang@analog.com>

Some people need flow control on their ports, so now boards can support
that via any GPIOs.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/serial/Kconfig | 24 ++++++++
drivers/serial/bfin_sport_uart.c | 111 ++++++++++++++++++++++++++++++++++----
drivers/serial/bfin_sport_uart.h | 11 ++++
3 files changed, 135 insertions(+), 11 deletions(-)

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 302836a..6325830 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -1443,24 +1443,48 @@ config SERIAL_BFIN_SPORT0_UART
help
Enable UART over SPORT0

+config SERIAL_BFIN_SPORT0_UART_CTSRTS
+ bool "Enable UART over SPORT0 hardware flow control"
+ depends on SERIAL_BFIN_SPORT0_UART
+ help
+ Enable hardware flow control in the driver.
+
config SERIAL_BFIN_SPORT1_UART
bool "Enable UART over SPORT1"
depends on SERIAL_BFIN_SPORT
help
Enable UART over SPORT1

+config SERIAL_BFIN_SPORT1_UART_CTSRTS
+ bool "Enable UART over SPORT1 hardware flow control"
+ depends on SERIAL_BFIN_SPORT1_UART
+ help
+ Enable hardware flow control in the driver.
+
config SERIAL_BFIN_SPORT2_UART
bool "Enable UART over SPORT2"
depends on SERIAL_BFIN_SPORT && (BF54x || BF538 || BF539)
help
Enable UART over SPORT2

+config SERIAL_BFIN_SPORT2_UART_CTSRTS
+ bool "Enable UART over SPORT2 hardware flow control"
+ depends on SERIAL_BFIN_SPORT2_UART
+ help
+ Enable hardware flow control in the driver.
+
config SERIAL_BFIN_SPORT3_UART
bool "Enable UART over SPORT3"
depends on SERIAL_BFIN_SPORT && (BF54x || BF538 || BF539)
help
Enable UART over SPORT3

+config SERIAL_BFIN_SPORT3_UART_CTSRTS
+ bool "Enable UART over SPORT3 hardware flow control"
+ depends on SERIAL_BFIN_SPORT3_UART
+ help
+ Enable hardware flow control in the driver.
+
config SERIAL_TIMBERDALE
tristate "Support for timberdale UART"
select SERIAL_CORE
diff --git a/drivers/serial/bfin_sport_uart.c b/drivers/serial/bfin_sport_uart.c
index 7925266..8cb0a40 100644
--- a/drivers/serial/bfin_sport_uart.c
+++ b/drivers/serial/bfin_sport_uart.c
@@ -48,6 +48,10 @@ struct sport_uart_port {
unsigned short txmask2;
unsigned char stopb;
/* unsigned char parib; */
+#ifdef CONFIG_SERIAL_BFIN_SPORT_CTSRTS
+ int cts_pin;
+ int rts_pin;
+#endif
};

static void sport_uart_tx_chars(struct sport_uart_port *up);
@@ -198,6 +202,59 @@ static irqreturn_t sport_uart_err_irq(int irq, void *dev_id)
return IRQ_HANDLED;
}

+#ifdef CONFIG_SERIAL_BFIN_SPORT_CTSRTS
+static unsigned int sport_get_mctrl(struct uart_port *port)
+{
+ struct sport_uart_port *up = (struct sport_uart_port *)port;
+ if (up->cts_pin < 0)
+ return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+
+ /* CTS PIN is negative assertive. */
+ if (SPORT_UART_GET_CTS(up))
+ return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
+ else
+ return TIOCM_DSR | TIOCM_CAR;
+}
+
+static void sport_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+ struct sport_uart_port *up = (struct sport_uart_port *)port;
+ if (up->rts_pin < 0)
+ return;
+
+ /* RTS PIN is negative assertive. */
+ if (mctrl & TIOCM_RTS)
+ SPORT_UART_ENABLE_RTS(up);
+ else
+ SPORT_UART_DISABLE_RTS(up);
+}
+
+/*
+ * Handle any change of modem status signal.
+ */
+static irqreturn_t sport_mctrl_cts_int(int irq, void *dev_id)
+{
+ struct sport_uart_port *up = (struct sport_uart_port *)dev_id;
+ unsigned int status;
+
+ status = sport_get_mctrl(&up->port);
+ uart_handle_cts_change(&up->port, status & TIOCM_CTS);
+
+ return IRQ_HANDLED;
+}
+#else
+static unsigned int sport_get_mctrl(struct uart_port *port)
+{
+ pr_debug("%s enter\n", __func__);
+ return TIOCM_CTS | TIOCM_CD | TIOCM_DSR;
+}
+
+static void sport_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+ pr_debug("%s enter\n", __func__);
+}
+#endif
+
/* Reqeust IRQ, Setup clock */
static int sport_startup(struct uart_port *port)
{
@@ -226,6 +283,21 @@ static int sport_startup(struct uart_port *port)
goto fail2;
}

+#ifdef CONFIG_SERIAL_BFIN_SPORT_CTSRTS
+ if (up->cts_pin >= 0) {
+ if (request_irq(gpio_to_irq(up->cts_pin),
+ sport_mctrl_cts_int,
+ IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING |
+ IRQF_DISABLED, "BFIN_SPORT_UART_CTS", up)) {
+ up->cts_pin = -1;
+ dev_info(port->dev, "Unable to attach BlackFin UART \
+ over SPORT CTS interrupt. So, disable it.\n");
+ }
+ }
+ if (up->rts_pin >= 0)
+ gpio_direction_output(up->rts_pin, 0);
+#endif
+
return 0;
fail2:
free_irq(up->port.irq+1, up);
@@ -283,17 +355,6 @@ static unsigned int sport_tx_empty(struct uart_port *port)
return 0;
}

-static unsigned int sport_get_mctrl(struct uart_port *port)
-{
- pr_debug("%s enter\n", __func__);
- return (TIOCM_CTS | TIOCM_CD | TIOCM_DSR);
-}
-
-static void sport_set_mctrl(struct uart_port *port, unsigned int mctrl)
-{
- pr_debug("%s enter\n", __func__);
-}
-
static void sport_stop_tx(struct uart_port *port)
{
struct sport_uart_port *up = (struct sport_uart_port *)port;
@@ -364,6 +425,10 @@ static void sport_shutdown(struct uart_port *port)
free_irq(up->port.irq, up);
free_irq(up->port.irq+1, up);
free_irq(up->err_irq, up);
+#ifdef CONFIG_SERIAL_BFIN_SPORT_CTSRTS
+ if (up->cts_pin >= 0)
+ free_irq(gpio_to_irq(up->cts_pin), up);
+#endif
}

static const char *sport_type(struct uart_port *port)
@@ -536,7 +601,11 @@ sport_uart_console_setup(struct console *co, char *options)
int baud = 57600;
int bits = 8;
int parity = 'n';
+# ifdef CONFIG_SERIAL_BFIN_SPORT_CTSRTS
+ int flow = 'r';
+# else
int flow = 'n';
+# endif

/* Check whether an invalid uart number has been specified */
if (co->index < 0 || co->index >= BFIN_SPORT_UART_MAX_PORTS)
@@ -729,6 +798,22 @@ static int __devinit sport_uart_probe(struct platform_device *pdev)
ret = -ENOENT;
goto out_error_unmap;
}
+#ifdef CONFIG_SERIAL_BFIN_SPORT_CTSRTS
+ res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+ if (res == NULL)
+ sport->cts_pin = -1;
+ else
+ sport->cts_pin = res->start;
+
+ res = platform_get_resource(pdev, IORESOURCE_IO, 1);
+ if (res == NULL)
+ sport->rts_pin = -1;
+ else
+ sport->rts_pin = res->start;
+
+ if (sport->rts_pin >= 0)
+ gpio_request(sport->rts_pin, DRV_NAME);
+#endif
}

#ifdef CONFIG_SERIAL_BFIN_SPORT_CONSOLE
@@ -767,6 +852,10 @@ static int __devexit sport_uart_remove(struct platform_device *pdev)

if (sport) {
uart_remove_one_port(&sport_uart_reg, &sport->port);
+#ifdef CONFIG_SERIAL_BFIN_CTSRTS
+ if (sport->rts_pin >= 0)
+ gpio_free(sport->rts_pin);
+#endif
iounmap(sport->port.membase);
peripheral_free_list(
(unsigned short *)pdev->dev.platform_data);
diff --git a/drivers/serial/bfin_sport_uart.h b/drivers/serial/bfin_sport_uart.h
index 9791fcc..9ce253e 100644
--- a/drivers/serial/bfin_sport_uart.h
+++ b/drivers/serial/bfin_sport_uart.h
@@ -72,4 +72,15 @@

#define SPORT_TX_FIFO_SIZE 8

+#define SPORT_UART_GET_CTS(x) gpio_get_value(x->cts_pin)
+#define SPORT_UART_DISABLE_RTS(x) gpio_set_value(x->rts_pin, 1)
+#define SPORT_UART_ENABLE_RTS(x) gpio_set_value(x->rts_pin, 0)
+
+#if defined(CONFIG_SERIAL_BFIN_SPORT0_UART_CTSRTS) \
+ || defined(CONFIG_SERIAL_BFIN_SPORT1_UART_CTSRTS) \
+ || defined(CONFIG_SERIAL_BFIN_SPORT2_UART_CTSRTS) \
+ || defined(CONFIG_SERIAL_BFIN_SPORT3_UART_CTSRTS)
+# define CONFIG_SERIAL_BFIN_SPORT_CTSRTS
+#endif
+
#endif /* _BFIN_SPORT_UART_H */
--
1.7.0.3


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