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84130aace8
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>
143 lines
3.4 KiB
C
143 lines
3.4 KiB
C
/*
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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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