[PATCH RESEND 3/5] tty/serial: Add GPIOLIB helpers for controlling modem lines
Yegor Yefremov
yegor_sub1 at visionsystems.de
Tue May 20 02:26:07 PDT 2014
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 at gmail.com>
> Acked-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Tested-by: Yegor Yefremov <yegorslists at 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
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