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>
110 lines
2.6 KiB
C
110 lines
2.6 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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#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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