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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-29 05:44:11 +00:00
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>
This commit is contained in:
Richard Genoud
Greg Kroah-Hartman
parent
fa3909320c
commit
84130aace8
5 changed files with 284 additions and 0 deletions
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@ -429,3 +429,28 @@ thus:
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struct uart_port port;
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int my_stuff;
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};
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Modem control lines via GPIO
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----------------------------
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Some helpers are provided in order to set/get modem control lines via GPIO.
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mctrl_gpio_init(dev, idx):
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This will get the {cts,rts,...}-gpios from device tree if they are
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present and request them, set direction etc, and return an
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allocated structure. devm_* functions are used, so there's no need
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to call mctrl_gpio_free().
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mctrl_gpio_free(dev, gpios):
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This will free the requested gpios in mctrl_gpio_init().
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As devm_* function are used, there's generally no need to call
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this function.
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mctrl_gpio_to_gpiod(gpios, gidx)
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This returns the gpio structure associated to the modem line index.
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mctrl_gpio_set(gpios, mctrl):
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This will sets the gpios according to the mctrl state.
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mctrl_gpio_get(gpios, mctrl):
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This will update mctrl with the gpios values.
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@ -1553,4 +1553,7 @@ config SERIAL_MEN_Z135
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endmenu
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config SERIAL_MCTRL_GPIO
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tristate
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endif # TTY
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@ -92,3 +92,6 @@ obj-$(CONFIG_SERIAL_ARC) += arc_uart.o
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obj-$(CONFIG_SERIAL_RP2) += rp2.o
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obj-$(CONFIG_SERIAL_FSL_LPUART) += fsl_lpuart.o
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obj-$(CONFIG_SERIAL_MEN_Z135) += men_z135_uart.o
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# GPIOLIB helpers for modem control lines
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obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
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143
drivers/tty/serial/serial_mctrl_gpio.c
Normal file
143
drivers/tty/serial/serial_mctrl_gpio.c
Normal file
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@ -0,0 +1,143 @@
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/*
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* Helpers for controlling modem lines via GPIO
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*
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* Copyright (C) 2014 Paratronic S.A.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/err.h>
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#include <linux/device.h>
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#include <linux/gpio/consumer.h>
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#include <uapi/asm-generic/termios.h>
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#include "serial_mctrl_gpio.h"
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struct mctrl_gpios {
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struct gpio_desc *gpio[UART_GPIO_MAX];
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};
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static const struct {
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const char *name;
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unsigned int mctrl;
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bool dir_out;
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} mctrl_gpios_desc[UART_GPIO_MAX] = {
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{ "cts", TIOCM_CTS, false, },
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{ "dsr", TIOCM_DSR, false, },
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{ "dcd", TIOCM_CD, false, },
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{ "rng", TIOCM_RNG, false, },
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{ "rts", TIOCM_RTS, true, },
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{ "dtr", TIOCM_DTR, true, },
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{ "out1", TIOCM_OUT1, true, },
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{ "out2", TIOCM_OUT2, true, },
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};
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void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
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{
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enum mctrl_gpio_idx i;
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if (IS_ERR_OR_NULL(gpios))
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return;
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for (i = 0; i < UART_GPIO_MAX; i++)
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if (!IS_ERR_OR_NULL(gpios->gpio[i]) &&
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mctrl_gpios_desc[i].dir_out)
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gpiod_set_value(gpios->gpio[i],
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!!(mctrl & mctrl_gpios_desc[i].mctrl));
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_set);
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struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
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enum mctrl_gpio_idx gidx)
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{
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if (!IS_ERR_OR_NULL(gpios) && !IS_ERR_OR_NULL(gpios->gpio[gidx]))
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return gpios->gpio[gidx];
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else
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return NULL;
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
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unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
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{
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enum mctrl_gpio_idx i;
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/*
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* return it unchanged if the structure is not allocated
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*/
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if (IS_ERR_OR_NULL(gpios))
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return *mctrl;
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for (i = 0; i < UART_GPIO_MAX; i++) {
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if (!IS_ERR_OR_NULL(gpios->gpio[i]) &&
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!mctrl_gpios_desc[i].dir_out) {
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if (gpiod_get_value(gpios->gpio[i]))
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*mctrl |= mctrl_gpios_desc[i].mctrl;
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else
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*mctrl &= ~mctrl_gpios_desc[i].mctrl;
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}
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}
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return *mctrl;
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_get);
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struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
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{
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struct mctrl_gpios *gpios;
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enum mctrl_gpio_idx i;
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int err;
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gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
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if (!gpios)
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return ERR_PTR(-ENOMEM);
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for (i = 0; i < UART_GPIO_MAX; i++) {
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gpios->gpio[i] = devm_gpiod_get_index(dev,
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mctrl_gpios_desc[i].name,
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idx);
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/*
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* The GPIOs are maybe not all filled,
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* this is not an error.
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*/
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if (IS_ERR_OR_NULL(gpios->gpio[i]))
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continue;
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if (mctrl_gpios_desc[i].dir_out)
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err = gpiod_direction_output(gpios->gpio[i], 0);
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else
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err = gpiod_direction_input(gpios->gpio[i]);
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if (err) {
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dev_dbg(dev, "Unable to set direction for %s GPIO",
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mctrl_gpios_desc[i].name);
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devm_gpiod_put(dev, gpios->gpio[i]);
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gpios->gpio[i] = NULL;
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}
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}
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return gpios;
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_init);
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void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
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{
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enum mctrl_gpio_idx i;
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if (IS_ERR_OR_NULL(gpios))
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return;
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for (i = 0; i < UART_GPIO_MAX; i++)
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if (!IS_ERR_OR_NULL(gpios->gpio[i]))
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devm_gpiod_put(dev, gpios->gpio[i]);
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devm_kfree(dev, gpios);
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}
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EXPORT_SYMBOL_GPL(mctrl_gpio_free);
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110
drivers/tty/serial/serial_mctrl_gpio.h
Normal file
110
drivers/tty/serial/serial_mctrl_gpio.h
Normal file
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@ -0,0 +1,110 @@
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/*
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* Helpers for controlling modem lines via GPIO
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*
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* Copyright (C) 2014 Paratronic S.A.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#ifndef __SERIAL_MCTRL_GPIO__
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#define __SERIAL_MCTRL_GPIO__
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#include <linux/err.h>
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#include <linux/device.h>
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#include <linux/gpio/consumer.h>
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enum mctrl_gpio_idx {
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UART_GPIO_CTS,
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UART_GPIO_DSR,
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UART_GPIO_DCD,
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UART_GPIO_RNG,
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UART_GPIO_RI = UART_GPIO_RNG,
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UART_GPIO_RTS,
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UART_GPIO_DTR,
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UART_GPIO_OUT1,
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UART_GPIO_OUT2,
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UART_GPIO_MAX,
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};
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/*
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* Opaque descriptor for modem lines controlled by GPIOs
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*/
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struct mctrl_gpios;
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#ifdef CONFIG_GPIOLIB
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/*
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* Set state of the modem control output lines via GPIOs.
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*/
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void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl);
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/*
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* Get state of the modem control output lines from GPIOs.
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* The mctrl flags are updated and returned.
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*/
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unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl);
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/*
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* Returns the associated struct gpio_desc to the modem line gidx
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*/
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struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
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enum mctrl_gpio_idx gidx);
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/*
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* Request and set direction of modem control lines GPIOs.
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* devm_* functions are used, so there's no need to call mctrl_gpio_free().
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* Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
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* allocation error.
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*/
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struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx);
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/*
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* Free the mctrl_gpios structure.
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* Normally, this function will not be called, as the GPIOs will
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* be disposed of by the resource management code.
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*/
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void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
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#else /* GPIOLIB */
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static inline
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void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
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{
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}
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static inline
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unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
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{
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return *mctrl;
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}
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static inline
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struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
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enum mctrl_gpio_idx gidx)
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{
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return ERR_PTR(-ENOSYS);
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}
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static inline
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struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
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{
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return ERR_PTR(-ENOSYS);
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}
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static inline
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void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
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{
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}
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#endif /* GPIOLIB */
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#endif
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