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author | Richard Genoud <richard.genoud@gmail.com> | 2014-05-13 20:20:43 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-28 12:49:14 -0700 |
commit | 84130aace83989c1dba073ed98dad721d2060258 (patch) | |
tree | e313e54a9276328a551825f58fc867aa02f8acf1 /drivers/tty/serial/serial_mctrl_gpio.c | |
parent | fa3909320c00286c6b9d6ade16bc6d44f940379c (diff) | |
download | linux-stable-84130aace83989c1dba073ed98dad721d2060258.tar.gz linux-stable-84130aace83989c1dba073ed98dad721d2060258.tar.bz2 linux-stable-84130aace83989c1dba073ed98dad721d2060258.zip |
tty/serial: Add GPIOLIB helpers for controlling modem lines
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/serial_mctrl_gpio.c')
-rw-r--r-- | drivers/tty/serial/serial_mctrl_gpio.c | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c new file mode 100644 index 000000000000..bf9560ffe3f4 --- /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); |