drivers/tty/serial/serial_mctrl_gpio.h

   1 /*
   2  * Helpers for controlling modem lines via GPIO
   3  *
   4  * Copyright (C) 2014 Paratronic S.A.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #ifndef __SERIAL_MCTRL_GPIO__
  19 #define __SERIAL_MCTRL_GPIO__
  20
  21 #include <linux/err.h>
  22 #include <linux/device.h>
  23 #include <linux/gpio/consumer.h>
  24
  25 enum mctrl_gpio_idx {
  26         UART_GPIO_CTS,
  27         UART_GPIO_DSR,
  28         UART_GPIO_DCD,
  29         UART_GPIO_RNG,
  30         UART_GPIO_RI = UART_GPIO_RNG,
  31         UART_GPIO_RTS,
  32         UART_GPIO_DTR,
  33         UART_GPIO_OUT1,
  34         UART_GPIO_OUT2,
  35         UART_GPIO_MAX,
  36 };
  37
  38 /*
  39  * Opaque descriptor for modem lines controlled by GPIOs
  40  */
  41 struct mctrl_gpios;
  42
  43 #ifdef CONFIG_GPIOLIB
  44
  45 /*
  46  * Set state of the modem control output lines via GPIOs.
  47  */
  48 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl);
  49
  50 /*
  51  * Get state of the modem control output lines from GPIOs.
  52  * The mctrl flags are updated and returned.
  53  */
  54 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl);
  55
  56 /*
  57  * Returns the associated struct gpio_desc to the modem line gidx
  58  */
  59 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
  60                                       enum mctrl_gpio_idx gidx);
  61
  62 /*
  63  * Request and set direction of modem control lines GPIOs.
  64  * devm_* functions are used, so there's no need to call mctrl_gpio_free().
  65  * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
  66  * allocation error.
  67  */
  68 struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx);
  69
  70 /*
  71  * Free the mctrl_gpios structure.
  72  * Normally, this function will not be called, as the GPIOs will
  73  * be disposed of by the resource management code.
  74  */
  75 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
  76
  77 #else /* GPIOLIB */
  78
  79 static inline
  80 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
  81 {
  82 }
  83
  84 static inline
  85 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
  86 {
  87         return *mctrl;
  88 }
  89
  90 static inline
  91 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
  92                                       enum mctrl_gpio_idx gidx)
  93 {
  94         return ERR_PTR(-ENOSYS);
  95 }
  96
  97 static inline
  98 struct mctrl_gpios *mctrl_gpio_init(struct device *dev, unsigned int idx)
  99 {
 100         return ERR_PTR(-ENOSYS);
 101 }
 102
 103 static inline
 104 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
 105 {
 106 }
 107
 108 #endif /* GPIOLIB */
 109
 110 #endif