[PATCH RESEND 0/5] tty/serial: Add helpers to use GPIOs to control modem lines and implement atmel_serial.c

[PATCH RESEND 0/5] tty/serial: Add helpers to use GPIOs to control modem lines and implement atmel_serial.c

[Richard Genoud]

This patch series is a leftover of http://www.spinics.net/lists/arm-kernel/msg314242.html
that missed 3.15 because it caused merge conflicts.

The USART controllers on sam9x5 chips (and also all AT91/SAMA5 chips
but at91rm9200) are not capable of handling DTR/DSR/DCD/RI signal.
Moreover, even if the controller can handle CTS/RTS, the dedicated
CTS/RTS pins may be already muxed for other peripherals (LCDC/EMAC/MMC).

So this patchset adds the possibility to control those lines via GPIO,
as it is done for RTS in the patch "switch atmel serial to use gpiolib"

NB: The 1st patch should make it for 3.15-final since it corrects a
device tree binding documentation example that has been introduced in 3.15-rc1.

Patch 1: For 3.15-final: fix GPIO_ACTIVE_LOW usage in device-tree documentation.
Patch 2: For 3.16: implements at91_gpiolib_get_direction used in patch 4
Patch 3: For 3.16: implements the generic helpers to control modem lines via GPIO.
Patch 4: For 3.16: implements modem control lines in atmel_serial atmel_serial.
Patch 5: For 3.16: implements the interrupts of CTS/DSR/DCD/RI.

This is based on v3.15-rc5.

Tested on at91sam9g35, with a null modem cable between 2 serial ports,
one with CTS/RTS controlled by the USART controller, the other via GPIO,
full duplex transfers.
Did some tests also with null modem cables on a PC, and with real modems.

Richard Genoud (5):
  tty/serial: atmel_serial: Fix device tree documentation
  ARM: at91: gpio: implement get_direction
  tty/serial: Add GPIOLIB helpers for controlling modem lines
  tty/serial: at91: use mctrl_gpio helpers
  tty/serial: at91: add interrupts for modem control lines

 .../devicetree/bindings/serial/atmel-usart.txt     |   12 +-
 Documentation/serial/driver                        |   25 +++
 arch/arm/mach-at91/at91rm9200_devices.c            |   16 +-
 arch/arm/mach-at91/at91sam9260_devices.c           |    7 -
 arch/arm/mach-at91/at91sam9261_devices.c           |    4 -
 arch/arm/mach-at91/at91sam9263_devices.c           |    4 -
 arch/arm/mach-at91/at91sam9g45_devices.c           |    5 -
 arch/arm/mach-at91/at91sam9rl_devices.c            |    5 -
 arch/arm/mach-at91/gpio.c                          |   13 ++
 drivers/tty/serial/Kconfig                         |    4 +
 drivers/tty/serial/Makefile                        |    3 +
 drivers/tty/serial/atmel_serial.c                  |  230 ++++++++++++++++----
 drivers/tty/serial/serial_mctrl_gpio.c             |  143 ++++++++++++
 drivers/tty/serial/serial_mctrl_gpio.h             |  110 ++++++++++
 include/linux/platform_data/atmel.h                |    1 -
 15 files changed, 509 insertions(+), 73 deletions(-)
 create mode 100644 drivers/tty/serial/serial_mctrl_gpio.c
 create mode 100644 drivers/tty/serial/serial_mctrl_gpio.h

-- 
1.7.10.4

[PATCH RESEND 1/5] tty/serial: atmel_serial: Fix device tree documentation

[Richard Genoud]

RTS pin is an active low pin.
For now, this doesn't change anything as the ACTIVE_LOW flag is not
handled in atmel_serial, but it will be in 3.16.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
---
 Documentation/devicetree/bindings/serial/atmel-usart.txt |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/serial/atmel-usart.txt b/Documentation/devicetree/bindings/serial/atmel-usart.txt
index 17c1042..2f7aad7 100644
--- a/Documentation/devicetree/bindings/serial/atmel-usart.txt
+++ b/Documentation/devicetree/bindings/serial/atmel-usart.txt
@@ -35,7 +35,7 @@ Example:
 		clock-names = "usart";
 		atmel,use-dma-rx;
 		atmel,use-dma-tx;
-		rts-gpios = <&pioD 15 0>;
+		rts-gpios = <&pioD 15 GPIO_ACTIVE_LOW>;
 	};
 
 - use DMA:
-- 
1.7.10.4

[PATCH RESEND 2/5] ARM: at91: gpio: implement get_direction

[Richard Genoud]

This is needed for gpiod_get_direction().
Otherwise, it returns -EINVAL.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
---
 arch/arm/mach-at91/gpio.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/arm/mach-at91/gpio.c b/arch/arm/mach-at91/gpio.c
index a5afcf7..afbe340 100644
--- a/arch/arm/mach-at91/gpio.c
+++ b/arch/arm/mach-at91/gpio.c
@@ -49,6 +49,7 @@ static int at91_gpiolib_request(struct gpio_chip *chip, unsigned offset);
 static void at91_gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip);
 static void at91_gpiolib_set(struct gpio_chip *chip, unsigned offset, int val);
 static int at91_gpiolib_get(struct gpio_chip *chip, unsigned offset);
+static int at91_gpiolib_get_direction(struct gpio_chip *chip, unsigned offset);
 static int at91_gpiolib_direction_output(struct gpio_chip *chip,
 					 unsigned offset, int val);
 static int at91_gpiolib_direction_input(struct gpio_chip *chip,
@@ -60,6 +61,7 @@ static int at91_gpiolib_to_irq(struct gpio_chip *chip, unsigned offset);
 		.chip = {						\
 			.label		  = name,			\
 			.request	  = at91_gpiolib_request,	\
+			.get_direction    = at91_gpiolib_get_direction, \
 			.direction_input  = at91_gpiolib_direction_input, \
 			.direction_output = at91_gpiolib_direction_output, \
 			.get		  = at91_gpiolib_get,		\
@@ -799,6 +801,17 @@ static int at91_gpiolib_request(struct gpio_chip *chip, unsigned offset)
 	return 0;
 }
 
+static int at91_gpiolib_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+	struct at91_gpio_chip *at91_gpio = to_at91_gpio_chip(chip);
+	void __iomem *pio = at91_gpio->regbase;
+	unsigned mask = 1 << offset;
+	u32 osr;
+
+	osr = __raw_readl(pio + PIO_OSR);
+	return !(osr & mask);
+}
+
 static int at91_gpiolib_direction_input(struct gpio_chip *chip,
 					unsigned offset)
 {
-- 
1.7.10.4

[PATCH RESEND 3/5] tty/serial: Add GPIOLIB helpers for controlling modem lines

[Richard Genoud]

This patch add some helpers to control modem lines (CTS/RTS/DSR...) via
GPIO.
This will be useful for many boards which have a serial controller that
only handle CTS/RTS pins (or even just RX/TX).

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 Documentation/serial/driver            |   25 ++++++
 drivers/tty/serial/Kconfig             |    3 +
 drivers/tty/serial/Makefile            |    3 +
 drivers/tty/serial/serial_mctrl_gpio.c |  143 ++++++++++++++++++++++++++++++++
 drivers/tty/serial/serial_mctrl_gpio.h |  110 ++++++++++++++++++++++++
 5 files changed, 284 insertions(+)
 create mode 100644 drivers/tty/serial/serial_mctrl_gpio.c
 create mode 100644 drivers/tty/serial/serial_mctrl_gpio.h

diff --git a/Documentation/serial/driver b/Documentation/serial/driver
index c3a7689..3bba1ae 100644
--- a/Documentation/serial/driver
+++ b/Documentation/serial/driver
@@ -429,3 +429,28 @@ thus:
 		struct uart_port	port;
 		int			my_stuff;
 	};
+
+Modem control lines via GPIO
+----------------------------
+
+Some helpers are provided in order to set/get modem control lines via GPIO.
+
+mctrl_gpio_init(dev, idx):
+	This will get the {cts,rts,...}-gpios from device tree if they are
+	present and request them, set direction etc, and return an
+	allocated structure. devm_* functions are used, so there's no need
+	to call mctrl_gpio_free().
+
+mctrl_gpio_free(dev, gpios):
+	This will free the requested gpios in mctrl_gpio_init().
+	As devm_* function are used, there's generally no need to call
+	this function.
+
+mctrl_gpio_to_gpiod(gpios, gidx)
+	This returns the gpio structure associated to the modem line index.
+
+mctrl_gpio_set(gpios, mctrl):
+	This will sets the gpios according to the mctrl state.
+
+mctrl_gpio_get(gpios, mctrl):
+	This will update mctrl with the gpios values.
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 5d9b01a..95afd31 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -1510,4 +1510,7 @@ config SERIAL_ST_ASC_CONSOLE
 
 endmenu
 
+config SERIAL_MCTRL_GPIO
+	tristate
+
 endif # TTY
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 3680854..bcf31da 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -87,3 +87,6 @@ obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o
 obj-$(CONFIG_SERIAL_ARC)	+= arc_uart.o
 obj-$(CONFIG_SERIAL_RP2)	+= rp2.o
 obj-$(CONFIG_SERIAL_FSL_LPUART)	+= fsl_lpuart.o
+
+# GPIOLIB helpers for modem control lines
+obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
new file mode 100644
index 0000000..bf9560f
--- /dev/null
+++ b/drivers/tty/serial/serial_mctrl_gpio.c
@@ -0,0 +1,143 @@
+/*
+ * Helpers for controlling modem lines via GPIO
+ *
+ * Copyright (C) 2014 Paratronic S.A.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <uapi/asm-generic/termios.h>
+
+#include "serial_mctrl_gpio.h"
+
+struct mctrl_gpios {
+	struct gpio_desc *gpio[UART_GPIO_MAX];
+};
+
+static const struct {
+	const char *name;
+	unsigned int mctrl;
+	bool dir_out;
+} mctrl_gpios_desc[UART_GPIO_MAX] = {
+	{ "cts", TIOCM_CTS, false, },
+	{ "dsr", TIOCM_DSR, false, },
+	{ "dcd", TIOCM_CD, false, },
+	{ "rng", TIOCM_RNG, false, },
+	{ "rts", TIOCM_RTS, true, },
+	{ "dtr", TIOCM_DTR, true, },
+	{ "out1", TIOCM_OUT1, true, },
+	{ "out2", TIOCM_OUT2, true, },
+};
+
+void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
+{
+	enum mctrl_gpio_idx i;
+
+	if (IS_ERR_OR_NULL(gpios))
+		return;
+
+	for (i = 0; i < UART_GPIO_MAX; i++)
+		if (!IS_ERR_OR_NULL(gpios->gpio[i]) &&
+		    mctrl_gpios_desc[i].dir_out)
+			gpiod_set_value(gpios->gpio[i],
+					!!(mctrl & mctrl_gpios_desc[i].mctrl));
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_set);
+
+struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
+				      enum mctrl_gpio_idx gidx)
+{
+	if (!IS_ERR_OR_NULL(gpios) && !IS_ERR_OR_NULL(gpios->gpio[gidx]))
+		return gpios->gpio[gidx];
+	else
+		return NULL;
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
+
+unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
+{
+	enum mctrl_gpio_idx i;
+
+	/*
+	 * return it unchanged if the structure is not allocated
+	 */
+	if (IS_ERR_OR_NULL(gpios))
+		return *mctrl;
+
+	for (i = 0; i < UART_GPIO_MAX; i++) {
+		if (!IS_ERR_OR_NULL(gpios->gpio[i]) &&
+		    !mctrl_gpios_desc[i].dir_out) {
+			if (gpiod_get_value(gpios->gpio[i]))
+				*mctrl |= mctrl_gpios_desc[i].mctrl;
+			else
+				*mctrl &= ~mctrl_gpios_desc[i].mctrl;
+		}
+	}
+
+	return *mctrl;
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_get);
+
+struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
+{
+	struct mctrl_gpios *gpios;
+	enum mctrl_gpio_idx i;
+	int err;
+
+	gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
+	if (!gpios)
+		return ERR_PTR(-ENOMEM);
+
+	for (i = 0; i < UART_GPIO_MAX; i++) {
+		gpios->gpio[i] = devm_gpiod_get_index(dev,
+						      mctrl_gpios_desc[i].name,
+						      idx);
+
+		/*
+		 * The GPIOs are maybe not all filled,
+		 * this is not an error.
+		 */
+		if (IS_ERR_OR_NULL(gpios->gpio[i]))
+			continue;
+
+		if (mctrl_gpios_desc[i].dir_out)
+			err = gpiod_direction_output(gpios->gpio[i], 0);
+		else
+			err = gpiod_direction_input(gpios->gpio[i]);
+		if (err) {
+			dev_dbg(dev, "Unable to set direction for %s GPIO",
+				mctrl_gpios_desc[i].name);
+			devm_gpiod_put(dev, gpios->gpio[i]);
+			gpios->gpio[i] = NULL;
+		}
+	}
+
+	return gpios;
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_init);
+
+void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
+{
+	enum mctrl_gpio_idx i;
+
+	if (IS_ERR_OR_NULL(gpios))
+		return;
+
+	for (i = 0; i < UART_GPIO_MAX; i++)
+		if (!IS_ERR_OR_NULL(gpios->gpio[i]))
+			devm_gpiod_put(dev, gpios->gpio[i]);
+	devm_kfree(dev, gpios);
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_free);
diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h
new file mode 100644
index 0000000..400ba04
--- /dev/null
+++ b/drivers/tty/serial/serial_mctrl_gpio.h
@@ -0,0 +1,110 @@
+/*
+ * Helpers for controlling modem lines via GPIO
+ *
+ * Copyright (C) 2014 Paratronic S.A.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#ifndef __SERIAL_MCTRL_GPIO__
+#define __SERIAL_MCTRL_GPIO__
+
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+
+enum mctrl_gpio_idx {
+	UART_GPIO_CTS,
+	UART_GPIO_DSR,
+	UART_GPIO_DCD,
+	UART_GPIO_RNG,
+	UART_GPIO_RI = UART_GPIO_RNG,
+	UART_GPIO_RTS,
+	UART_GPIO_DTR,
+	UART_GPIO_OUT1,
+	UART_GPIO_OUT2,
+	UART_GPIO_MAX,
+};
+
+/*
+ * Opaque descriptor for modem lines controlled by GPIOs
+ */
+struct mctrl_gpios;
+
+#ifdef CONFIG_GPIOLIB
+
+/*
+ * Set state of the modem control output lines via GPIOs.
+ */
+void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl);
+
+/*
+ * Get state of the modem control output lines from GPIOs.
+ * The mctrl flags are updated and returned.
+ */
+unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl);
+
+/*
+ * Returns the associated struct gpio_desc to the modem line gidx
+ */
+struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
+				      enum mctrl_gpio_idx gidx);
+
+/*
+ * Request and set direction of modem control lines GPIOs.
+ * devm_* functions are used, so there's no need to call mctrl_gpio_free().
+ * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
+ * allocation error.
+ */
+struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx);
+
+/*
+ * Free the mctrl_gpios structure.
+ * Normally, this function will not be called, as the GPIOs will
+ * be disposed of by the resource management code.
+ */
+void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
+
+#else /* GPIOLIB */
+
+static inline
+void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
+{
+}
+
+static inline
+unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
+{
+	return *mctrl;
+}
+
+static inline
+struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
+				      enum mctrl_gpio_idx gidx)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline
+struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline
+void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
+{
+}
+
+#endif /* GPIOLIB */
+
+#endif
-- 
1.7.10.4

[PATCH RESEND 3/5] tty/serial: Add GPIOLIB helpers for controlling modem lines

[Yegor Yefremov]

On 13.05.2014 20:20, Richard Genoud wrote:
> This patch add some helpers to control modem lines (CTS/RTS/DSR...) via
> GPIO.
> This will be useful for many boards which have a serial controller that
> only handle CTS/RTS pins (or even just RX/TX).
>
> Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Tested-by: Yegor Yefremov <yegorslists@googlemail.com>


> ---
>  Documentation/serial/driver            |   25 ++++++
>  drivers/tty/serial/Kconfig             |    3 +
>  drivers/tty/serial/Makefile            |    3 +
>  drivers/tty/serial/serial_mctrl_gpio.c |  143 ++++++++++++++++++++++++++++++++
>  drivers/tty/serial/serial_mctrl_gpio.h |  110 ++++++++++++++++++++++++
>  5 files changed, 284 insertions(+)
>  create mode 100644 drivers/tty/serial/serial_mctrl_gpio.c
>  create mode 100644 drivers/tty/serial/serial_mctrl_gpio.h
>
> diff --git a/Documentation/serial/driver b/Documentation/serial/driver
> index c3a7689..3bba1ae 100644
> --- a/Documentation/serial/driver
> +++ b/Documentation/serial/driver
> @@ -429,3 +429,28 @@ thus:
>  		struct uart_port	port;
>  		int			my_stuff;
>  	};
> +
> +Modem control lines via GPIO
> +----------------------------
> +
> +Some helpers are provided in order to set/get modem control lines via GPIO.
> +
> +mctrl_gpio_init(dev, idx):
> +	This will get the {cts,rts,...}-gpios from device tree if they are
> +	present and request them, set direction etc, and return an
> +	allocated structure. devm_* functions are used, so there's no need
> +	to call mctrl_gpio_free().
> +
> +mctrl_gpio_free(dev, gpios):
> +	This will free the requested gpios in mctrl_gpio_init().
> +	As devm_* function are used, there's generally no need to call
> +	this function.
> +
> +mctrl_gpio_to_gpiod(gpios, gidx)
> +	This returns the gpio structure associated to the modem line index.
> +
> +mctrl_gpio_set(gpios, mctrl):
> +	This will sets the gpios according to the mctrl state.
> +
> +mctrl_gpio_get(gpios, mctrl):
> +	This will update mctrl with the gpios values.
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 5d9b01a..95afd31 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -1510,4 +1510,7 @@ config SERIAL_ST_ASC_CONSOLE
>  
>  endmenu
>  
> +config SERIAL_MCTRL_GPIO
> +	tristate
> +
>  endif # TTY
> diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
> index 3680854..bcf31da 100644
> --- a/drivers/tty/serial/Makefile
> +++ b/drivers/tty/serial/Makefile
> @@ -87,3 +87,6 @@ obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o
>  obj-$(CONFIG_SERIAL_ARC)	+= arc_uart.o
>  obj-$(CONFIG_SERIAL_RP2)	+= rp2.o
>  obj-$(CONFIG_SERIAL_FSL_LPUART)	+= fsl_lpuart.o
> +
> +# GPIOLIB helpers for modem control lines
> +obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
> diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
> new file mode 100644
> index 0000000..bf9560f
> --- /dev/null
> +++ b/drivers/tty/serial/serial_mctrl_gpio.c
> @@ -0,0 +1,143 @@
> +/*
> + * Helpers for controlling modem lines via GPIO
> + *
> + * Copyright (C) 2014 Paratronic S.A.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/err.h>
> +#include <linux/device.h>
> +#include <linux/gpio/consumer.h>
> +#include <uapi/asm-generic/termios.h>
> +
> +#include "serial_mctrl_gpio.h"
> +
> +struct mctrl_gpios {
> +	struct gpio_desc *gpio[UART_GPIO_MAX];
> +};
> +
> +static const struct {
> +	const char *name;
> +	unsigned int mctrl;
> +	bool dir_out;
> +} mctrl_gpios_desc[UART_GPIO_MAX] = {
> +	{ "cts", TIOCM_CTS, false, },
> +	{ "dsr", TIOCM_DSR, false, },
> +	{ "dcd", TIOCM_CD, false, },
> +	{ "rng", TIOCM_RNG, false, },
> +	{ "rts", TIOCM_RTS, true, },
> +	{ "dtr", TIOCM_DTR, true, },
> +	{ "out1", TIOCM_OUT1, true, },
> +	{ "out2", TIOCM_OUT2, true, },
> +};
> +
> +void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
> +{
> +	enum mctrl_gpio_idx i;
> +
> +	if (IS_ERR_OR_NULL(gpios))
> +		return;
> +
> +	for (i = 0; i < UART_GPIO_MAX; i++)
> +		if (!IS_ERR_OR_NULL(gpios->gpio[i]) &&
> +		    mctrl_gpios_desc[i].dir_out)
> +			gpiod_set_value(gpios->gpio[i],
> +					!!(mctrl & mctrl_gpios_desc[i].mctrl));
> +}
> +EXPORT_SYMBOL_GPL(mctrl_gpio_set);
> +
> +struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
> +				      enum mctrl_gpio_idx gidx)
> +{
> +	if (!IS_ERR_OR_NULL(gpios) && !IS_ERR_OR_NULL(gpios->gpio[gidx]))
> +		return gpios->gpio[gidx];
> +	else
> +		return NULL;
> +}
> +EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
> +
> +unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
> +{
> +	enum mctrl_gpio_idx i;
> +
> +	/*
> +	 * return it unchanged if the structure is not allocated
> +	 */
> +	if (IS_ERR_OR_NULL(gpios))
> +		return *mctrl;
> +
> +	for (i = 0; i < UART_GPIO_MAX; i++) {
> +		if (!IS_ERR_OR_NULL(gpios->gpio[i]) &&
> +		    !mctrl_gpios_desc[i].dir_out) {
> +			if (gpiod_get_value(gpios->gpio[i]))
> +				*mctrl |= mctrl_gpios_desc[i].mctrl;
> +			else
> +				*mctrl &= ~mctrl_gpios_desc[i].mctrl;
> +		}
> +	}
> +
> +	return *mctrl;
> +}
> +EXPORT_SYMBOL_GPL(mctrl_gpio_get);
> +
> +struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
> +{
> +	struct mctrl_gpios *gpios;
> +	enum mctrl_gpio_idx i;
> +	int err;
> +
> +	gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
> +	if (!gpios)
> +		return ERR_PTR(-ENOMEM);
> +
> +	for (i = 0; i < UART_GPIO_MAX; i++) {
> +		gpios->gpio[i] = devm_gpiod_get_index(dev,
> +						      mctrl_gpios_desc[i].name,
> +						      idx);
> +
> +		/*
> +		 * The GPIOs are maybe not all filled,
> +		 * this is not an error.
> +		 */
> +		if (IS_ERR_OR_NULL(gpios->gpio[i]))
> +			continue;
> +
> +		if (mctrl_gpios_desc[i].dir_out)
> +			err = gpiod_direction_output(gpios->gpio[i], 0);
> +		else
> +			err = gpiod_direction_input(gpios->gpio[i]);
> +		if (err) {
> +			dev_dbg(dev, "Unable to set direction for %s GPIO",
> +				mctrl_gpios_desc[i].name);
> +			devm_gpiod_put(dev, gpios->gpio[i]);
> +			gpios->gpio[i] = NULL;
> +		}
> +	}
> +
> +	return gpios;
> +}
> +EXPORT_SYMBOL_GPL(mctrl_gpio_init);
> +
> +void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
> +{
> +	enum mctrl_gpio_idx i;
> +
> +	if (IS_ERR_OR_NULL(gpios))
> +		return;
> +
> +	for (i = 0; i < UART_GPIO_MAX; i++)
> +		if (!IS_ERR_OR_NULL(gpios->gpio[i]))
> +			devm_gpiod_put(dev, gpios->gpio[i]);
> +	devm_kfree(dev, gpios);
> +}
> +EXPORT_SYMBOL_GPL(mctrl_gpio_free);
> diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h
> new file mode 100644
> index 0000000..400ba04
> --- /dev/null
> +++ b/drivers/tty/serial/serial_mctrl_gpio.h
> @@ -0,0 +1,110 @@
> +/*
> + * Helpers for controlling modem lines via GPIO
> + *
> + * Copyright (C) 2014 Paratronic S.A.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef __SERIAL_MCTRL_GPIO__
> +#define __SERIAL_MCTRL_GPIO__
> +
> +#include <linux/err.h>
> +#include <linux/device.h>
> +#include <linux/gpio/consumer.h>
> +
> +enum mctrl_gpio_idx {
> +	UART_GPIO_CTS,
> +	UART_GPIO_DSR,
> +	UART_GPIO_DCD,
> +	UART_GPIO_RNG,
> +	UART_GPIO_RI = UART_GPIO_RNG,
> +	UART_GPIO_RTS,
> +	UART_GPIO_DTR,
> +	UART_GPIO_OUT1,
> +	UART_GPIO_OUT2,
> +	UART_GPIO_MAX,
> +};
> +
> +/*
> + * Opaque descriptor for modem lines controlled by GPIOs
> + */
> +struct mctrl_gpios;
> +
> +#ifdef CONFIG_GPIOLIB
> +
> +/*
> + * Set state of the modem control output lines via GPIOs.
> + */
> +void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl);
> +
> +/*
> + * Get state of the modem control output lines from GPIOs.
> + * The mctrl flags are updated and returned.
> + */
> +unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl);
> +
> +/*
> + * Returns the associated struct gpio_desc to the modem line gidx
> + */
> +struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
> +				      enum mctrl_gpio_idx gidx);
> +
> +/*
> + * Request and set direction of modem control lines GPIOs.
> + * devm_* functions are used, so there's no need to call mctrl_gpio_free().
> + * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
> + * allocation error.
> + */
> +struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx);
> +
> +/*
> + * Free the mctrl_gpios structure.
> + * Normally, this function will not be called, as the GPIOs will
> + * be disposed of by the resource management code.
> + */
> +void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
> +
> +#else /* GPIOLIB */
> +
> +static inline
> +void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
> +{
> +}
> +
> +static inline
> +unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
> +{
> +	return *mctrl;
> +}
> +
> +static inline
> +struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
> +				      enum mctrl_gpio_idx gidx)
> +{
> +	return ERR_PTR(-ENOSYS);
> +}
> +
> +static inline
> +struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
> +{
> +	return ERR_PTR(-ENOSYS);
> +}
> +
> +static inline
> +void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
> +{
> +}
> +
> +#endif /* GPIOLIB */
> +
> +#endif

[PATCH RESEND 3/5] tty/serial: Add GPIOLIB helpers for controlling modem lines

[Greg Kroah-Hartman]

On Tue, May 13, 2014 at 08:20:43PM +0200, Richard Genoud wrote:
> This patch add some helpers to control modem lines (CTS/RTS/DSR...) via
> GPIO.
> This will be useful for many boards which have a serial controller that
> only handle CTS/RTS pins (or even just RX/TX).
> 
> Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
> Tested-by: Yegor Yefremov <yegorslists@googlemail.com>
> ---
>  Documentation/serial/driver            |   25 ++++++
>  drivers/tty/serial/Kconfig             |    3 +
>  drivers/tty/serial/Makefile            |    3 +
>  drivers/tty/serial/serial_mctrl_gpio.c |  143 ++++++++++++++++++++++++++++++++
>  drivers/tty/serial/serial_mctrl_gpio.h |  110 ++++++++++++++++++++++++
>  5 files changed, 284 insertions(+)
>  create mode 100644 drivers/tty/serial/serial_mctrl_gpio.c
>  create mode 100644 drivers/tty/serial/serial_mctrl_gpio.h
> 
> diff --git a/Documentation/serial/driver b/Documentation/serial/driver
> index c3a7689..3bba1ae 100644
> --- a/Documentation/serial/driver
> +++ b/Documentation/serial/driver
> @@ -429,3 +429,28 @@ thus:
>  		struct uart_port	port;
>  		int			my_stuff;
>  	};
> +
> +Modem control lines via GPIO
> +----------------------------
> +
> +Some helpers are provided in order to set/get modem control lines via GPIO.
> +
> +mctrl_gpio_init(dev, idx):
> +	This will get the {cts,rts,...}-gpios from device tree if they are
> +	present and request them, set direction etc, and return an
> +	allocated structure. devm_* functions are used, so there's no need
> +	to call mctrl_gpio_free().
> +
> +mctrl_gpio_free(dev, gpios):
> +	This will free the requested gpios in mctrl_gpio_init().
> +	As devm_* function are used, there's generally no need to call
> +	this function.
> +
> +mctrl_gpio_to_gpiod(gpios, gidx)
> +	This returns the gpio structure associated to the modem line index.
> +
> +mctrl_gpio_set(gpios, mctrl):
> +	This will sets the gpios according to the mctrl state.
> +
> +mctrl_gpio_get(gpios, mctrl):
> +	This will update mctrl with the gpios values.
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 5d9b01a..95afd31 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -1510,4 +1510,7 @@ config SERIAL_ST_ASC_CONSOLE
>  
>  endmenu
>  
> +config SERIAL_MCTRL_GPIO
> +	tristate

Why is this added here?  Who is going to use it?

> +
>  endif # TTY
> diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
> index 3680854..bcf31da 100644
> --- a/drivers/tty/serial/Makefile
> +++ b/drivers/tty/serial/Makefile
> @@ -87,3 +87,6 @@ obj-$(CONFIG_SERIAL_EFM32_UART) += efm32-uart.o
>  obj-$(CONFIG_SERIAL_ARC)	+= arc_uart.o
>  obj-$(CONFIG_SERIAL_RP2)	+= rp2.o
>  obj-$(CONFIG_SERIAL_FSL_LPUART)	+= fsl_lpuart.o
> +
> +# GPIOLIB helpers for modem control lines
> +obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o

This chunk doesn't apply anymore :(

[PATCH RESEND 3/5] tty/serial: Add GPIOLIB helpers for controlling modem lines

[Greg Kroah-Hartman]

On Wed, May 28, 2014 at 12:45:50PM -0700, Greg Kroah-Hartman wrote:
> On Tue, May 13, 2014 at 08:20:43PM +0200, Richard Genoud wrote:
> > This patch add some helpers to control modem lines (CTS/RTS/DSR...) via
> > GPIO.
> > This will be useful for many boards which have a serial controller that
> > only handle CTS/RTS pins (or even just RX/TX).
> > 
> > Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
> > Tested-by: Yegor Yefremov <yegorslists@googlemail.com>
> > ---
> >  Documentation/serial/driver            |   25 ++++++
> >  drivers/tty/serial/Kconfig             |    3 +
> >  drivers/tty/serial/Makefile            |    3 +
> >  drivers/tty/serial/serial_mctrl_gpio.c |  143 ++++++++++++++++++++++++++++++++
> >  drivers/tty/serial/serial_mctrl_gpio.h |  110 ++++++++++++++++++++++++
> >  5 files changed, 284 insertions(+)
> >  create mode 100644 drivers/tty/serial/serial_mctrl_gpio.c
> >  create mode 100644 drivers/tty/serial/serial_mctrl_gpio.h
> > 
> > diff --git a/Documentation/serial/driver b/Documentation/serial/driver
> > index c3a7689..3bba1ae 100644
> > --- a/Documentation/serial/driver
> > +++ b/Documentation/serial/driver
> > @@ -429,3 +429,28 @@ thus:
> >  		struct uart_port	port;
> >  		int			my_stuff;
> >  	};
> > +
> > +Modem control lines via GPIO
> > +----------------------------
> > +
> > +Some helpers are provided in order to set/get modem control lines via GPIO.
> > +
> > +mctrl_gpio_init(dev, idx):
> > +	This will get the {cts,rts,...}-gpios from device tree if they are
> > +	present and request them, set direction etc, and return an
> > +	allocated structure. devm_* functions are used, so there's no need
> > +	to call mctrl_gpio_free().
> > +
> > +mctrl_gpio_free(dev, gpios):
> > +	This will free the requested gpios in mctrl_gpio_init().
> > +	As devm_* function are used, there's generally no need to call
> > +	this function.
> > +
> > +mctrl_gpio_to_gpiod(gpios, gidx)
> > +	This returns the gpio structure associated to the modem line index.
> > +
> > +mctrl_gpio_set(gpios, mctrl):
> > +	This will sets the gpios according to the mctrl state.
> > +
> > +mctrl_gpio_get(gpios, mctrl):
> > +	This will update mctrl with the gpios values.
> > diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> > index 5d9b01a..95afd31 100644
> > --- a/drivers/tty/serial/Kconfig
> > +++ b/drivers/tty/serial/Kconfig
> > @@ -1510,4 +1510,7 @@ config SERIAL_ST_ASC_CONSOLE
> >  
> >  endmenu
> >  
> > +config SERIAL_MCTRL_GPIO
> > +	tristate
> 
> Why is this added here?  Who is going to use it?

Ah, the next patch does, nevermind...

[PATCH RESEND 4/5] tty/serial: at91: use mctrl_gpio helpers

[Richard Genoud]

On sam9x5, dedicated CTS (and RTS) pins are unusable together with the
LCDC, the EMAC, or the MMC because they share the same line.

Moreover, the USART controller doesn't handle DTR/DSR/DCD/RI signals,
so we have to control them via GPIO.

This patch permits to use GPIOs to control the CTS/RTS/DTR/DSR/DCD/RI
signals.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
 .../devicetree/bindings/serial/atmel-usart.txt     |   10 +-
 arch/arm/mach-at91/at91rm9200_devices.c            |   16 +--
 arch/arm/mach-at91/at91sam9260_devices.c           |    7 --
 arch/arm/mach-at91/at91sam9261_devices.c           |    4 -
 arch/arm/mach-at91/at91sam9263_devices.c           |    4 -
 arch/arm/mach-at91/at91sam9g45_devices.c           |    5 -
 arch/arm/mach-at91/at91sam9rl_devices.c            |    5 -
 drivers/tty/serial/Kconfig                         |    1 +
 drivers/tty/serial/atmel_serial.c                  |  105 +++++++++++++-------
 include/linux/platform_data/atmel.h                |    1 -
 10 files changed, 89 insertions(+), 69 deletions(-)

diff --git a/Documentation/devicetree/bindings/serial/atmel-usart.txt b/Documentation/devicetree/bindings/serial/atmel-usart.txt
index 2f7aad7..a6391e7 100644
--- a/Documentation/devicetree/bindings/serial/atmel-usart.txt
+++ b/Documentation/devicetree/bindings/serial/atmel-usart.txt
@@ -13,8 +13,9 @@ Required properties:
 Optional properties:
 - atmel,use-dma-rx: use of PDC or DMA for receiving data
 - atmel,use-dma-tx: use of PDC or DMA for transmitting data
-- rts-gpios: specify a GPIO for RTS line. It will use specified PIO instead of the peripheral
-  function pin for the USART RTS feature. If unsure, don't specify this property.
+- {rts,cts,dtr,dsr,rng,dcd}-gpios: specify a GPIO for RTS/CTS/DTR/DSR/RI/DCD line respectively.
+  It will use specified PIO instead of the peripheral function pin for the USART feature.
+  If unsure, don't specify this property.
 - add dma bindings for dma transfer:
 	- dmas: DMA specifier, consisting of a phandle to DMA controller node,
 		memory peripheral interface and USART DMA channel ID, FIFO configuration.
@@ -36,6 +37,11 @@ Example:
 		atmel,use-dma-rx;
 		atmel,use-dma-tx;
 		rts-gpios = <&pioD 15 GPIO_ACTIVE_LOW>;
+		cts-gpios = <&pioD 16 GPIO_ACTIVE_LOW>;
+		dtr-gpios = <&pioD 17 GPIO_ACTIVE_LOW>;
+		dsr-gpios = <&pioD 18 GPIO_ACTIVE_LOW>;
+		dcd-gpios = <&pioD 20 GPIO_ACTIVE_LOW>;
+		rng-gpios = <&pioD 19 GPIO_ACTIVE_LOW>;
 	};
 
 - use DMA:
diff --git a/arch/arm/mach-at91/at91rm9200_devices.c b/arch/arm/mach-at91/at91rm9200_devices.c
index f3f19f2..291a90a 100644
--- a/arch/arm/mach-at91/at91rm9200_devices.c
+++ b/arch/arm/mach-at91/at91rm9200_devices.c
@@ -15,6 +15,7 @@
 
 #include <linux/dma-mapping.h>
 #include <linux/gpio.h>
+#include <linux/gpio/driver.h>
 #include <linux/platform_device.h>
 #include <linux/i2c-gpio.h>
 
@@ -923,7 +924,6 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
 	.use_dma_tx	= 0,
 	.use_dma_rx	= 0,		/* DBGU not capable of receive DMA */
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -962,7 +962,14 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
+};
+
+static struct gpiod_lookup_table uart0_gpios_table = {
+	.dev_id = "atmel_usart",
+	.table = {
+		GPIO_LOOKUP("pioA", 21, "rts", GPIO_ACTIVE_LOW),
+		{ },
+	},
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -993,7 +1000,7 @@ static inline void configure_usart0_pins(unsigned pins)
 		 * We need to drive the pin manually. The serial driver will driver
 		 * this to high when initializing.
 		 */
-		uart0_data.rts_gpio = AT91_PIN_PA21;
+		gpiod_add_lookup_table(&uart0_gpios_table);
 	}
 }
 
@@ -1013,7 +1020,6 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -1065,7 +1071,6 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);
@@ -1109,7 +1114,6 @@ static struct resource uart3_resources[] = {
 static struct atmel_uart_data uart3_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart3_dmamask = DMA_BIT_MASK(32);
diff --git a/arch/arm/mach-at91/at91sam9260_devices.c b/arch/arm/mach-at91/at91sam9260_devices.c
index a028292..526453e 100644
--- a/arch/arm/mach-at91/at91sam9260_devices.c
+++ b/arch/arm/mach-at91/at91sam9260_devices.c
@@ -820,7 +820,6 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
 	.use_dma_tx	= 0,
 	.use_dma_rx	= 0,		/* DBGU not capable of receive DMA */
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -859,7 +858,6 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -911,7 +909,6 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -955,7 +952,6 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);
@@ -999,7 +995,6 @@ static struct resource uart3_resources[] = {
 static struct atmel_uart_data uart3_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart3_dmamask = DMA_BIT_MASK(32);
@@ -1043,7 +1038,6 @@ static struct resource uart4_resources[] = {
 static struct atmel_uart_data uart4_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart4_dmamask = DMA_BIT_MASK(32);
@@ -1082,7 +1076,6 @@ static struct resource uart5_resources[] = {
 static struct atmel_uart_data uart5_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart5_dmamask = DMA_BIT_MASK(32);
diff --git a/arch/arm/mach-at91/at91sam9261_devices.c b/arch/arm/mach-at91/at91sam9261_devices.c
index 80e3589..b5f7a72 100644
--- a/arch/arm/mach-at91/at91sam9261_devices.c
+++ b/arch/arm/mach-at91/at91sam9261_devices.c
@@ -881,7 +881,6 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
 	.use_dma_tx	= 0,
 	.use_dma_rx	= 0,		/* DBGU not capable of receive DMA */
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -920,7 +919,6 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -964,7 +962,6 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -1008,7 +1005,6 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);
diff --git a/arch/arm/mach-at91/at91sam9263_devices.c b/arch/arm/mach-at91/at91sam9263_devices.c
index 43d53d6..39803c3 100644
--- a/arch/arm/mach-at91/at91sam9263_devices.c
+++ b/arch/arm/mach-at91/at91sam9263_devices.c
@@ -1325,7 +1325,6 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
 	.use_dma_tx	= 0,
 	.use_dma_rx	= 0,		/* DBGU not capable of receive DMA */
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -1364,7 +1363,6 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -1408,7 +1406,6 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -1452,7 +1449,6 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);
diff --git a/arch/arm/mach-at91/at91sam9g45_devices.c b/arch/arm/mach-at91/at91sam9g45_devices.c
index dab362c..4dfedd3 100644
--- a/arch/arm/mach-at91/at91sam9g45_devices.c
+++ b/arch/arm/mach-at91/at91sam9g45_devices.c
@@ -1588,7 +1588,6 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
 	.use_dma_tx	= 0,
 	.use_dma_rx	= 0,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -1627,7 +1626,6 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -1671,7 +1669,6 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -1715,7 +1712,6 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);
@@ -1759,7 +1755,6 @@ static struct resource uart3_resources[] = {
 static struct atmel_uart_data uart3_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart3_dmamask = DMA_BIT_MASK(32);
diff --git a/arch/arm/mach-at91/at91sam9rl_devices.c b/arch/arm/mach-at91/at91sam9rl_devices.c
index 428fc41..f759850 100644
--- a/arch/arm/mach-at91/at91sam9rl_devices.c
+++ b/arch/arm/mach-at91/at91sam9rl_devices.c
@@ -957,7 +957,6 @@ static struct resource dbgu_resources[] = {
 static struct atmel_uart_data dbgu_data = {
 	.use_dma_tx	= 0,
 	.use_dma_rx	= 0,		/* DBGU not capable of receive DMA */
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 dbgu_dmamask = DMA_BIT_MASK(32);
@@ -996,7 +995,6 @@ static struct resource uart0_resources[] = {
 static struct atmel_uart_data uart0_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart0_dmamask = DMA_BIT_MASK(32);
@@ -1048,7 +1046,6 @@ static struct resource uart1_resources[] = {
 static struct atmel_uart_data uart1_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart1_dmamask = DMA_BIT_MASK(32);
@@ -1092,7 +1089,6 @@ static struct resource uart2_resources[] = {
 static struct atmel_uart_data uart2_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart2_dmamask = DMA_BIT_MASK(32);
@@ -1136,7 +1132,6 @@ static struct resource uart3_resources[] = {
 static struct atmel_uart_data uart3_data = {
 	.use_dma_tx	= 1,
 	.use_dma_rx	= 1,
-	.rts_gpio	= -EINVAL,
 };
 
 static u64 uart3_dmamask = DMA_BIT_MASK(32);
diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index 95afd31..6e748dc 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -97,6 +97,7 @@ config SERIAL_ATMEL
 	bool "AT91 / AT32 on-chip serial port support"
 	depends on ARCH_AT91 || AVR32
 	select SERIAL_CORE
+	select SERIAL_MCTRL_GPIO
 	help
 	  This enables the driver for the on-chip UARTs of the Atmel
 	  AT91 and AT32 processors.
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 53eeea1..43ca659 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -43,6 +43,8 @@
 #include <linux/platform_data/atmel.h>
 #include <linux/timer.h>
 #include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/err.h>
 
 #include <asm/io.h>
 #include <asm/ioctls.h>
@@ -57,6 +59,8 @@
 
 #include <linux/serial_core.h>
 
+#include "serial_mctrl_gpio.h"
+
 static void atmel_start_rx(struct uart_port *port);
 static void atmel_stop_rx(struct uart_port *port);
 
@@ -162,7 +166,7 @@ struct atmel_uart_port {
 	struct circ_buf		rx_ring;
 
 	struct serial_rs485	rs485;		/* rs485 settings */
-	int			rts_gpio;	/* optional RTS GPIO */
+	struct mctrl_gpios	*gpios;
 	unsigned int		tx_done_mask;
 	bool			is_usart;	/* usart or uart */
 	struct timer_list	uart_timer;	/* uart timer */
@@ -237,6 +241,50 @@ static bool atmel_use_dma_rx(struct uart_port *port)
 	return atmel_port->use_dma_rx;
 }
 
+static unsigned int atmel_get_lines_status(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	unsigned int status, ret = 0;
+
+	status = UART_GET_CSR(port);
+
+	mctrl_gpio_get(atmel_port->gpios, &ret);
+
+	if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios,
+						UART_GPIO_CTS))) {
+		if (ret & TIOCM_CTS)
+			status &= ~ATMEL_US_CTS;
+		else
+			status |= ATMEL_US_CTS;
+	}
+
+	if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios,
+						UART_GPIO_DSR))) {
+		if (ret & TIOCM_DSR)
+			status &= ~ATMEL_US_DSR;
+		else
+			status |= ATMEL_US_DSR;
+	}
+
+	if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios,
+						UART_GPIO_RI))) {
+		if (ret & TIOCM_RI)
+			status &= ~ATMEL_US_RI;
+		else
+			status |= ATMEL_US_RI;
+	}
+
+	if (!IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(atmel_port->gpios,
+						UART_GPIO_DCD))) {
+		if (ret & TIOCM_CD)
+			status &= ~ATMEL_US_DCD;
+		else
+			status |= ATMEL_US_DCD;
+	}
+
+	return status;
+}
+
 /* Enable or disable the rs485 support */
 void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 {
@@ -296,17 +344,6 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
 	unsigned int mode;
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-	/*
-	 * AT91RM9200 Errata #39: RTS0 is not internally connected
-	 * to PA21. We need to drive the pin as a GPIO.
-	 */
-	if (gpio_is_valid(atmel_port->rts_gpio)) {
-		if (mctrl & TIOCM_RTS)
-			gpio_set_value(atmel_port->rts_gpio, 0);
-		else
-			gpio_set_value(atmel_port->rts_gpio, 1);
-	}
-
 	if (mctrl & TIOCM_RTS)
 		control |= ATMEL_US_RTSEN;
 	else
@@ -319,6 +356,8 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
 
 	UART_PUT_CR(port, control);
 
+	mctrl_gpio_set(atmel_port->gpios, mctrl);
+
 	/* Local loopback mode? */
 	mode = UART_GET_MR(port) & ~ATMEL_US_CHMODE;
 	if (mctrl & TIOCM_LOOP)
@@ -346,7 +385,8 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
  */
 static u_int atmel_get_mctrl(struct uart_port *port)
 {
-	unsigned int status, ret = 0;
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	unsigned int ret = 0, status;
 
 	status = UART_GET_CSR(port);
 
@@ -362,7 +402,7 @@ static u_int atmel_get_mctrl(struct uart_port *port)
 	if (!(status & ATMEL_US_RI))
 		ret |= TIOCM_RI;
 
-	return ret;
+	return mctrl_gpio_get(atmel_port->gpios, &ret);
 }
 
 /*
@@ -1042,7 +1082,7 @@ static irqreturn_t atmel_interrupt(int irq, void *dev_id)
 	unsigned int status, pending, pass_counter = 0;
 
 	do {
-		status = UART_GET_CSR(port);
+		status = atmel_get_lines_status(port);
 		pending = status & UART_GET_IMR(port);
 		if (!pending)
 			break;
@@ -1568,7 +1608,7 @@ static int atmel_startup(struct uart_port *port)
 	}
 
 	/* Save current CSR for comparison in atmel_tasklet_func() */
-	atmel_port->irq_status_prev = UART_GET_CSR(port);
+	atmel_port->irq_status_prev = atmel_get_lines_status(port);
 	atmel_port->irq_status = atmel_port->irq_status_prev;
 
 	/*
@@ -2324,6 +2364,15 @@ static int atmel_serial_resume(struct platform_device *pdev)
 #define atmel_serial_resume NULL
 #endif
 
+static int atmel_init_gpios(struct atmel_uart_port *p, struct device *dev)
+{
+	p->gpios = mctrl_gpio_init(dev, 0);
+	if (IS_ERR_OR_NULL(p->gpios))
+		return -1;
+
+	return 0;
+}
+
 static int atmel_serial_probe(struct platform_device *pdev)
 {
 	struct atmel_uart_port *port;
@@ -2359,25 +2408,11 @@ static int atmel_serial_probe(struct platform_device *pdev)
 	port = &atmel_ports[ret];
 	port->backup_imr = 0;
 	port->uart.line = ret;
-	port->rts_gpio = -EINVAL; /* Invalid, zero could be valid */
-	if (pdata)
-		port->rts_gpio = pdata->rts_gpio;
-	else if (np)
-		port->rts_gpio = of_get_named_gpio(np, "rts-gpios", 0);
-
-	if (gpio_is_valid(port->rts_gpio)) {
-		ret = devm_gpio_request(&pdev->dev, port->rts_gpio, "RTS");
-		if (ret) {
-			dev_err(&pdev->dev, "error requesting RTS GPIO\n");
-			goto err;
-		}
-		/* Default to 1 as RTS is active low */
-		ret = gpio_direction_output(port->rts_gpio, 1);
-		if (ret) {
-			dev_err(&pdev->dev, "error setting up RTS GPIO\n");
-			goto err;
-		}
-	}
+
+	ret = atmel_init_gpios(port, &pdev->dev);
+	if (ret < 0)
+		dev_err(&pdev->dev, "%s",
+			"Failed to initialize GPIOs. The serial port may not work as expected");
 
 	ret = atmel_init_port(port, pdev);
 	if (ret)
diff --git a/include/linux/platform_data/atmel.h b/include/linux/platform_data/atmel.h
index e26b0c1..cea9f70 100644
--- a/include/linux/platform_data/atmel.h
+++ b/include/linux/platform_data/atmel.h
@@ -84,7 +84,6 @@ struct atmel_uart_data {
 	short			use_dma_rx;	/* use receive DMA? */
 	void __iomem		*regs;		/* virt. base address, if any */
 	struct serial_rs485	rs485;		/* rs485 settings */
-	int			rts_gpio;	/* optional RTS GPIO */
 };
 
  /* Touchscreen Controller */
-- 
1.7.10.4

[PATCH RESEND 5/5] tty/serial: at91: add interrupts for modem control lines

[Richard Genoud]

Handle CTS/DSR/RI/DCD GPIO interrupts in atmel_serial.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
---
 drivers/tty/serial/atmel_serial.c |  125 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 122 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 43ca659..3fceae0 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -45,6 +45,7 @@
 #include <linux/gpio.h>
 #include <linux/gpio/consumer.h>
 #include <linux/err.h>
+#include <linux/irq.h>
 
 #include <asm/io.h>
 #include <asm/ioctls.h>
@@ -167,7 +168,9 @@ struct atmel_uart_port {
 
 	struct serial_rs485	rs485;		/* rs485 settings */
 	struct mctrl_gpios	*gpios;
+	int			gpio_irq[UART_GPIO_MAX];
 	unsigned int		tx_done_mask;
+	bool			ms_irq_enabled;
 	bool			is_usart;	/* usart or uart */
 	struct timer_list	uart_timer;	/* uart timer */
 	int (*prepare_rx)(struct uart_port *port);
@@ -489,8 +492,38 @@ static void atmel_stop_rx(struct uart_port *port)
  */
 static void atmel_enable_ms(struct uart_port *port)
 {
-	UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC
-			| ATMEL_US_DCDIC | ATMEL_US_CTSIC);
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	uint32_t ier = 0;
+
+	/*
+	 * Interrupt should not be enabled twice
+	 */
+	if (atmel_port->ms_irq_enabled)
+		return;
+
+	atmel_port->ms_irq_enabled = true;
+
+	if (atmel_port->gpio_irq[UART_GPIO_CTS] >= 0)
+		enable_irq(atmel_port->gpio_irq[UART_GPIO_CTS]);
+	else
+		ier |= ATMEL_US_CTSIC;
+
+	if (atmel_port->gpio_irq[UART_GPIO_DSR] >= 0)
+		enable_irq(atmel_port->gpio_irq[UART_GPIO_DSR]);
+	else
+		ier |= ATMEL_US_DSRIC;
+
+	if (atmel_port->gpio_irq[UART_GPIO_RI] >= 0)
+		enable_irq(atmel_port->gpio_irq[UART_GPIO_RI]);
+	else
+		ier |= ATMEL_US_RIIC;
+
+	if (atmel_port->gpio_irq[UART_GPIO_DCD] >= 0)
+		enable_irq(atmel_port->gpio_irq[UART_GPIO_DCD]);
+	else
+		ier |= ATMEL_US_DCDIC;
+
+	UART_PUT_IER(port, ier);
 }
 
 /*
@@ -1079,11 +1112,31 @@ atmel_handle_status(struct uart_port *port, unsigned int pending,
 static irqreturn_t atmel_interrupt(int irq, void *dev_id)
 {
 	struct uart_port *port = dev_id;
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 	unsigned int status, pending, pass_counter = 0;
+	bool gpio_handled = false;
 
 	do {
 		status = atmel_get_lines_status(port);
 		pending = status & UART_GET_IMR(port);
+		if (!gpio_handled) {
+			/*
+			 * Dealing with GPIO interrupt
+			 */
+			if (irq == atmel_port->gpio_irq[UART_GPIO_CTS])
+				pending |= ATMEL_US_CTSIC;
+
+			if (irq == atmel_port->gpio_irq[UART_GPIO_DSR])
+				pending |= ATMEL_US_DSRIC;
+
+			if (irq == atmel_port->gpio_irq[UART_GPIO_RI])
+				pending |= ATMEL_US_RIIC;
+
+			if (irq == atmel_port->gpio_irq[UART_GPIO_DCD])
+				pending |= ATMEL_US_DCDIC;
+
+			gpio_handled = true;
+		}
 		if (!pending)
 			break;
 
@@ -1563,6 +1616,45 @@ static void atmel_get_ip_name(struct uart_port *port)
 	}
 }
 
+static void atmel_free_gpio_irq(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	enum mctrl_gpio_idx i;
+
+	for (i = 0; i < UART_GPIO_MAX; i++)
+		if (atmel_port->gpio_irq[i] >= 0)
+			free_irq(atmel_port->gpio_irq[i], port);
+}
+
+static int atmel_request_gpio_irq(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	int *irq = atmel_port->gpio_irq;
+	enum mctrl_gpio_idx i;
+	int err = 0;
+
+	for (i = 0; (i < UART_GPIO_MAX) && !err; i++) {
+		if (irq[i] < 0)
+			continue;
+
+		irq_set_status_flags(irq[i], IRQ_NOAUTOEN);
+		err = request_irq(irq[i], atmel_interrupt, IRQ_TYPE_EDGE_BOTH,
+				  "atmel_serial", port);
+		if (err)
+			dev_err(port->dev, "atmel_startup - Can't get %d irq\n",
+				irq[i]);
+	}
+
+	/*
+	 * If something went wrong, rollback.
+	 */
+	while (err && (--i >= 0))
+		if (irq[i] >= 0)
+			free_irq(irq[i], port);
+
+	return err;
+}
+
 /*
  * Perform initialization and enable port for reception
  */
@@ -1579,6 +1671,7 @@ static int atmel_startup(struct uart_port *port)
 	 * handle an unexpected interrupt
 	 */
 	UART_PUT_IDR(port, -1);
+	atmel_port->ms_irq_enabled = false;
 
 	/*
 	 * Allocate the IRQ
@@ -1591,6 +1684,13 @@ static int atmel_startup(struct uart_port *port)
 	}
 
 	/*
+	 * Get the GPIO lines IRQ
+	 */
+	retval = atmel_request_gpio_irq(port);
+	if (retval)
+		goto free_irq;
+
+	/*
 	 * Initialize DMA (if necessary)
 	 */
 	atmel_init_property(atmel_port, pdev);
@@ -1654,6 +1754,11 @@ static int atmel_startup(struct uart_port *port)
 	}
 
 	return 0;
+
+free_irq:
+	free_irq(port->irq, port);
+
+	return retval;
 }
 
 /*
@@ -1701,9 +1806,12 @@ static void atmel_shutdown(struct uart_port *port)
 	atmel_port->rx_ring.tail = 0;
 
 	/*
-	 * Free the interrupt
+	 * Free the interrupts
 	 */
 	free_irq(port->irq, port);
+	atmel_free_gpio_irq(port);
+
+	atmel_port->ms_irq_enabled = false;
 }
 
 /*
@@ -2366,10 +2474,21 @@ static int atmel_serial_resume(struct platform_device *pdev)
 
 static int atmel_init_gpios(struct atmel_uart_port *p, struct device *dev)
 {
+	enum mctrl_gpio_idx i;
+	struct gpio_desc *gpiod;
+
 	p->gpios = mctrl_gpio_init(dev, 0);
 	if (IS_ERR_OR_NULL(p->gpios))
 		return -1;
 
+	for (i = 0; i < UART_GPIO_MAX; i++) {
+		gpiod = mctrl_gpio_to_gpiod(p->gpios, i);
+		if (gpiod && (gpiod_get_direction(gpiod) == GPIOF_DIR_IN))
+			p->gpio_irq[i] = gpiod_to_irq(gpiod);
+		else
+			p->gpio_irq[i] = -EINVAL;
+	}
+
 	return 0;
 }
 
-- 
1.7.10.4

[PATCH RESEND 5/5] tty/serial: at91: add interrupts for modem control lines

[Peter Hurley]

Hi Richard,

On 05/13/2014 02:20 PM, Richard Genoud wrote:
> Handle CTS/DSR/RI/DCD GPIO interrupts in atmel_serial.
> 
> Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> ---
>  drivers/tty/serial/atmel_serial.c |  125 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 122 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index 43ca659..3fceae0 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -45,6 +45,7 @@
>  #include <linux/gpio.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/err.h>
> +#include <linux/irq.h>
>  
>  #include <asm/io.h>
>  #include <asm/ioctls.h>
> @@ -167,7 +168,9 @@ struct atmel_uart_port {
>  
>  	struct serial_rs485	rs485;		/* rs485 settings */
>  	struct mctrl_gpios	*gpios;
> +	int			gpio_irq[UART_GPIO_MAX];
>  	unsigned int		tx_done_mask;
> +	bool			ms_irq_enabled;
>  	bool			is_usart;	/* usart or uart */
>  	struct timer_list	uart_timer;	/* uart timer */
>  	int (*prepare_rx)(struct uart_port *port);
> @@ -489,8 +492,38 @@ static void atmel_stop_rx(struct uart_port *port)
>   */
>  static void atmel_enable_ms(struct uart_port *port)
>  {
> -	UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC
> -			| ATMEL_US_DCDIC | ATMEL_US_CTSIC);
> +	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> +	uint32_t ier = 0;
> +
> +	/*
> +	 * Interrupt should not be enabled twice
> +	 */
> +	if (atmel_port->ms_irq_enabled)
> +		return;
> +
> +	atmel_port->ms_irq_enabled = true;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_CTS] >= 0)
> +		enable_irq(atmel_port->gpio_irq[UART_GPIO_CTS]);
> +	else
> +		ier |= ATMEL_US_CTSIC;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_DSR] >= 0)
> +		enable_irq(atmel_port->gpio_irq[UART_GPIO_DSR]);
> +	else
> +		ier |= ATMEL_US_DSRIC;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_RI] >= 0)
> +		enable_irq(atmel_port->gpio_irq[UART_GPIO_RI]);
> +	else
> +		ier |= ATMEL_US_RIIC;
> +
> +	if (atmel_port->gpio_irq[UART_GPIO_DCD] >= 0)
> +		enable_irq(atmel_port->gpio_irq[UART_GPIO_DCD]);
> +	else
> +		ier |= ATMEL_US_DCDIC;

Where are these gpio irqs disabled if !UART_ENABLE_MS()?


> +
> +	UART_PUT_IER(port, ier);
>  }
>  
>  /*
> @@ -1079,11 +1112,31 @@ atmel_handle_status(struct uart_port *port, unsigned int pending,
>  static irqreturn_t atmel_interrupt(int irq, void *dev_id)
>  {
>  	struct uart_port *port = dev_id;
> +	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
>  	unsigned int status, pending, pass_counter = 0;
> +	bool gpio_handled = false;
>  
>  	do {
>  		status = atmel_get_lines_status(port);
>  		pending = status & UART_GET_IMR(port);
> +		if (!gpio_handled) {
> +			/*
> +			 * Dealing with GPIO interrupt
> +			 */
> +			if (irq == atmel_port->gpio_irq[UART_GPIO_CTS])
> +				pending |= ATMEL_US_CTSIC;
> +
> +			if (irq == atmel_port->gpio_irq[UART_GPIO_DSR])
> +				pending |= ATMEL_US_DSRIC;
> +
> +			if (irq == atmel_port->gpio_irq[UART_GPIO_RI])
> +				pending |= ATMEL_US_RIIC;
> +
> +			if (irq == atmel_port->gpio_irq[UART_GPIO_DCD])
> +				pending |= ATMEL_US_DCDIC;
> +
> +			gpio_handled = true;
> +		}
>  		if (!pending)
>  			break;
>  
> @@ -1563,6 +1616,45 @@ static void atmel_get_ip_name(struct uart_port *port)
>  	}
>  }
>  
> +static void atmel_free_gpio_irq(struct uart_port *port)
> +{
> +	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> +	enum mctrl_gpio_idx i;
> +
> +	for (i = 0; i < UART_GPIO_MAX; i++)
> +		if (atmel_port->gpio_irq[i] >= 0)
> +			free_irq(atmel_port->gpio_irq[i], port);
> +}
> +
> +static int atmel_request_gpio_irq(struct uart_port *port)
> +{
> +	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
> +	int *irq = atmel_port->gpio_irq;
> +	enum mctrl_gpio_idx i;
> +	int err = 0;
> +
> +	for (i = 0; (i < UART_GPIO_MAX) && !err; i++) {
> +		if (irq[i] < 0)
> +			continue;
> +
> +		irq_set_status_flags(irq[i], IRQ_NOAUTOEN);
> +		err = request_irq(irq[i], atmel_interrupt, IRQ_TYPE_EDGE_BOTH,
> +				  "atmel_serial", port);
> +		if (err)
> +			dev_err(port->dev, "atmel_startup - Can't get %d irq\n",
> +				irq[i]);
> +	}
> +
> +	/*
> +	 * If something went wrong, rollback.
> +	 */
> +	while (err && (--i >= 0))
> +		if (irq[i] >= 0)
> +			free_irq(irq[i], port);
> +
> +	return err;
> +}
> +
>  /*
>   * Perform initialization and enable port for reception
>   */
> @@ -1579,6 +1671,7 @@ static int atmel_startup(struct uart_port *port)
>  	 * handle an unexpected interrupt
>  	 */
>  	UART_PUT_IDR(port, -1);
> +	atmel_port->ms_irq_enabled = false;
>  
>  	/*
>  	 * Allocate the IRQ
> @@ -1591,6 +1684,13 @@ static int atmel_startup(struct uart_port *port)
>  	}
>  
>  	/*
> +	 * Get the GPIO lines IRQ
> +	 */
> +	retval = atmel_request_gpio_irq(port);
> +	if (retval)
> +		goto free_irq;
> +
> +	/*
>  	 * Initialize DMA (if necessary)
>  	 */
>  	atmel_init_property(atmel_port, pdev);
> @@ -1654,6 +1754,11 @@ static int atmel_startup(struct uart_port *port)
>  	}
>  
>  	return 0;
> +
> +free_irq:
> +	free_irq(port->irq, port);
> +
> +	return retval;
>  }
>  
>  /*
> @@ -1701,9 +1806,12 @@ static void atmel_shutdown(struct uart_port *port)
>  	atmel_port->rx_ring.tail = 0;
>  
>  	/*
> -	 * Free the interrupt
> +	 * Free the interrupts
>  	 */
>  	free_irq(port->irq, port);
> +	atmel_free_gpio_irq(port);
> +
> +	atmel_port->ms_irq_enabled = false;
>  }
>  
>  /*
> @@ -2366,10 +2474,21 @@ static int atmel_serial_resume(struct platform_device *pdev)
>  
>  static int atmel_init_gpios(struct atmel_uart_port *p, struct device *dev)
>  {
> +	enum mctrl_gpio_idx i;
> +	struct gpio_desc *gpiod;
> +
>  	p->gpios = mctrl_gpio_init(dev, 0);
>  	if (IS_ERR_OR_NULL(p->gpios))
>  		return -1;
>  
> +	for (i = 0; i < UART_GPIO_MAX; i++) {
> +		gpiod = mctrl_gpio_to_gpiod(p->gpios, i);
> +		if (gpiod && (gpiod_get_direction(gpiod) == GPIOF_DIR_IN))
> +			p->gpio_irq[i] = gpiod_to_irq(gpiod);
> +		else
> +			p->gpio_irq[i] = -EINVAL;
> +	}
> +
>  	return 0;
>  }
>  
> 

[PATCH RESEND 5/5] tty/serial: at91: add interrupts for modem control lines

[Richard Genoud]

2014-08-10 21:33 GMT+02:00 Peter Hurley <peter@hurleysoftware.com>:
> Hi Richard,

Hi !
Sorry for the delay !

> On 05/13/2014 02:20 PM, Richard Genoud wrote:
>> Handle CTS/DSR/RI/DCD GPIO interrupts in atmel_serial.
>>
>> Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
>> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
>> ---
>>  drivers/tty/serial/atmel_serial.c |  125 ++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 122 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
>> index 43ca659..3fceae0 100644
>> --- a/drivers/tty/serial/atmel_serial.c
>> +++ b/drivers/tty/serial/atmel_serial.c
>> @@ -45,6 +45,7 @@
>>  #include <linux/gpio.h>
>>  #include <linux/gpio/consumer.h>
>>  #include <linux/err.h>
>> +#include <linux/irq.h>
>>
>>  #include <asm/io.h>
>>  #include <asm/ioctls.h>
>> @@ -167,7 +168,9 @@ struct atmel_uart_port {
>>
>>       struct serial_rs485     rs485;          /* rs485 settings */
>>       struct mctrl_gpios      *gpios;
>> +     int                     gpio_irq[UART_GPIO_MAX];
>>       unsigned int            tx_done_mask;
>> +     bool                    ms_irq_enabled;
>>       bool                    is_usart;       /* usart or uart */
>>       struct timer_list       uart_timer;     /* uart timer */
>>       int (*prepare_rx)(struct uart_port *port);
>> @@ -489,8 +492,38 @@ static void atmel_stop_rx(struct uart_port *port)
>>   */
>>  static void atmel_enable_ms(struct uart_port *port)
>>  {
>> -     UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC
>> -                     | ATMEL_US_DCDIC | ATMEL_US_CTSIC);
>> +     struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
>> +     uint32_t ier = 0;
>> +
>> +     /*
>> +      * Interrupt should not be enabled twice
>> +      */
>> +     if (atmel_port->ms_irq_enabled)
>> +             return;
>> +
>> +     atmel_port->ms_irq_enabled = true;
>> +
>> +     if (atmel_port->gpio_irq[UART_GPIO_CTS] >= 0)
>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_CTS]);
>> +     else
>> +             ier |= ATMEL_US_CTSIC;
>> +
>> +     if (atmel_port->gpio_irq[UART_GPIO_DSR] >= 0)
>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_DSR]);
>> +     else
>> +             ier |= ATMEL_US_DSRIC;
>> +
>> +     if (atmel_port->gpio_irq[UART_GPIO_RI] >= 0)
>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_RI]);
>> +     else
>> +             ier |= ATMEL_US_RIIC;
>> +
>> +     if (atmel_port->gpio_irq[UART_GPIO_DCD] >= 0)
>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_DCD]);
>> +     else
>> +             ier |= ATMEL_US_DCDIC;
>
> Where are these gpio irqs disabled if !UART_ENABLE_MS()?
They are disabled in atmel_shutdown()/atmel_free_gpio_irq().
Like the doc says in Documentation/serial/driver
  enable_ms(port)
    Enable the modem status interrupts.

    This method may be called multiple times.  Modem status
    interrupts should be disabled when the shutdown method is
    called.

Regards,
Richard.

[PATCH RESEND 5/5] tty/serial: at91: add interrupts for modem control lines

[Peter Hurley]

On 09/01/2014 05:26 AM, Richard Genoud wrote:
> 2014-08-10 21:33 GMT+02:00 Peter Hurley <peter@hurleysoftware.com>:
>> Hi Richard,
> 
> Hi !
> Sorry for the delay !
> 
>> On 05/13/2014 02:20 PM, Richard Genoud wrote:
>>> Handle CTS/DSR/RI/DCD GPIO interrupts in atmel_serial.
>>>
>>> Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
>>> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
>>> ---
>>>  drivers/tty/serial/atmel_serial.c |  125 ++++++++++++++++++++++++++++++++++++-
>>>  1 file changed, 122 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
>>> index 43ca659..3fceae0 100644
>>> --- a/drivers/tty/serial/atmel_serial.c
>>> +++ b/drivers/tty/serial/atmel_serial.c
>>> @@ -45,6 +45,7 @@
>>>  #include <linux/gpio.h>
>>>  #include <linux/gpio/consumer.h>
>>>  #include <linux/err.h>
>>> +#include <linux/irq.h>
>>>
>>>  #include <asm/io.h>
>>>  #include <asm/ioctls.h>
>>> @@ -167,7 +168,9 @@ struct atmel_uart_port {
>>>
>>>       struct serial_rs485     rs485;          /* rs485 settings */
>>>       struct mctrl_gpios      *gpios;
>>> +     int                     gpio_irq[UART_GPIO_MAX];
>>>       unsigned int            tx_done_mask;
>>> +     bool                    ms_irq_enabled;
>>>       bool                    is_usart;       /* usart or uart */
>>>       struct timer_list       uart_timer;     /* uart timer */
>>>       int (*prepare_rx)(struct uart_port *port);
>>> @@ -489,8 +492,38 @@ static void atmel_stop_rx(struct uart_port *port)
>>>   */
>>>  static void atmel_enable_ms(struct uart_port *port)
>>>  {
>>> -     UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC
>>> -                     | ATMEL_US_DCDIC | ATMEL_US_CTSIC);
>>> +     struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
>>> +     uint32_t ier = 0;
>>> +
>>> +     /*
>>> +      * Interrupt should not be enabled twice
>>> +      */
>>> +     if (atmel_port->ms_irq_enabled)
>>> +             return;
>>> +
>>> +     atmel_port->ms_irq_enabled = true;
>>> +
>>> +     if (atmel_port->gpio_irq[UART_GPIO_CTS] >= 0)
>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_CTS]);
>>> +     else
>>> +             ier |= ATMEL_US_CTSIC;
>>> +
>>> +     if (atmel_port->gpio_irq[UART_GPIO_DSR] >= 0)
>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_DSR]);
>>> +     else
>>> +             ier |= ATMEL_US_DSRIC;
>>> +
>>> +     if (atmel_port->gpio_irq[UART_GPIO_RI] >= 0)
>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_RI]);
>>> +     else
>>> +             ier |= ATMEL_US_RIIC;
>>> +
>>> +     if (atmel_port->gpio_irq[UART_GPIO_DCD] >= 0)
>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_DCD]);
>>> +     else
>>> +             ier |= ATMEL_US_DCDIC;
>>
>> Where are these gpio irqs disabled if !UART_ENABLE_MS()?
> They are disabled in atmel_shutdown()/atmel_free_gpio_irq().
> Like the doc says in Documentation/serial/driver
>   enable_ms(port)
>     Enable the modem status interrupts.
> 
>     This method may be called multiple times.  Modem status
>     interrupts should be disabled when the shutdown method is
>     called.

Thanks for replying.

The point of the UART_ENABLE_MS() macro is to allow the UART driver
to determine if modem status interrupts need to be enabled when
handling the .set_termios() method.

When handling set_termios(), if UART_ENABLE_MS is false (ie., the
serial core does not require modem status interrupts), the UART
driver can and should turn modem status interrupts off.

It is _also_ true that "modem status interrupts should be disabled
when the shutdown method is called"; in fact, _all_ UART-sourced
interrupts should be disabled when the shutdown method is called.

Regards,
Peter Hurley

[PATCH RESEND 5/5] tty/serial: at91: add interrupts for modem control lines

[Richard Genoud]

2014-09-02 13:40 GMT+02:00 Peter Hurley <peter@hurleysoftware.com>:
> On 09/01/2014 05:26 AM, Richard Genoud wrote:
>> 2014-08-10 21:33 GMT+02:00 Peter Hurley <peter@hurleysoftware.com>:
>>> Hi Richard,
>>
>> Hi !
>> Sorry for the delay !
>>
>>> On 05/13/2014 02:20 PM, Richard Genoud wrote:
>>>> Handle CTS/DSR/RI/DCD GPIO interrupts in atmel_serial.
>>>>
>>>> Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
>>>> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>>> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
>>>> ---
>>>>  drivers/tty/serial/atmel_serial.c |  125 ++++++++++++++++++++++++++++++++++++-
>>>>  1 file changed, 122 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
>>>> index 43ca659..3fceae0 100644
>>>> --- a/drivers/tty/serial/atmel_serial.c
>>>> +++ b/drivers/tty/serial/atmel_serial.c
>>>> @@ -45,6 +45,7 @@
>>>>  #include <linux/gpio.h>
>>>>  #include <linux/gpio/consumer.h>
>>>>  #include <linux/err.h>
>>>> +#include <linux/irq.h>
>>>>
>>>>  #include <asm/io.h>
>>>>  #include <asm/ioctls.h>
>>>> @@ -167,7 +168,9 @@ struct atmel_uart_port {
>>>>
>>>>       struct serial_rs485     rs485;          /* rs485 settings */
>>>>       struct mctrl_gpios      *gpios;
>>>> +     int                     gpio_irq[UART_GPIO_MAX];
>>>>       unsigned int            tx_done_mask;
>>>> +     bool                    ms_irq_enabled;
>>>>       bool                    is_usart;       /* usart or uart */
>>>>       struct timer_list       uart_timer;     /* uart timer */
>>>>       int (*prepare_rx)(struct uart_port *port);
>>>> @@ -489,8 +492,38 @@ static void atmel_stop_rx(struct uart_port *port)
>>>>   */
>>>>  static void atmel_enable_ms(struct uart_port *port)
>>>>  {
>>>> -     UART_PUT_IER(port, ATMEL_US_RIIC | ATMEL_US_DSRIC
>>>> -                     | ATMEL_US_DCDIC | ATMEL_US_CTSIC);
>>>> +     struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
>>>> +     uint32_t ier = 0;
>>>> +
>>>> +     /*
>>>> +      * Interrupt should not be enabled twice
>>>> +      */
>>>> +     if (atmel_port->ms_irq_enabled)
>>>> +             return;
>>>> +
>>>> +     atmel_port->ms_irq_enabled = true;
>>>> +
>>>> +     if (atmel_port->gpio_irq[UART_GPIO_CTS] >= 0)
>>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_CTS]);
>>>> +     else
>>>> +             ier |= ATMEL_US_CTSIC;
>>>> +
>>>> +     if (atmel_port->gpio_irq[UART_GPIO_DSR] >= 0)
>>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_DSR]);
>>>> +     else
>>>> +             ier |= ATMEL_US_DSRIC;
>>>> +
>>>> +     if (atmel_port->gpio_irq[UART_GPIO_RI] >= 0)
>>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_RI]);
>>>> +     else
>>>> +             ier |= ATMEL_US_RIIC;
>>>> +
>>>> +     if (atmel_port->gpio_irq[UART_GPIO_DCD] >= 0)
>>>> +             enable_irq(atmel_port->gpio_irq[UART_GPIO_DCD]);
>>>> +     else
>>>> +             ier |= ATMEL_US_DCDIC;
>>>
>>> Where are these gpio irqs disabled if !UART_ENABLE_MS()?
>> They are disabled in atmel_shutdown()/atmel_free_gpio_irq().
>> Like the doc says in Documentation/serial/driver
>>   enable_ms(port)
>>     Enable the modem status interrupts.
>>
>>     This method may be called multiple times.  Modem status
>>     interrupts should be disabled when the shutdown method is
>>     called.
>
> Thanks for replying.
>
> The point of the UART_ENABLE_MS() macro is to allow the UART driver
> to determine if modem status interrupts need to be enabled when
> handling the .set_termios() method.
>
> When handling set_termios(), if UART_ENABLE_MS is false (ie., the
> serial core does not require modem status interrupts), the UART
> driver can and should turn modem status interrupts off.
>
> It is _also_ true that "modem status interrupts should be disabled
> when the shutdown method is called"; in fact, _all_ UART-sourced
> interrupts should be disabled when the shutdown method is called.

That's right. I totally missed that !
I'll come with a patch.

Thanks !!

Richard.