include/linux/pinctrl/pinconf-generic.h

   1 /*
   2  * Interface the generic pinconfig portions of the pinctrl subsystem
   3  *
   4  * Copyright (C) 2011 ST-Ericsson SA
   5  * Written on behalf of Linaro for ST-Ericsson
   6  * This interface is used in the core to keep track of pins.
   7  *
   8  * Author: Linus Walleij <linus.walleij@linaro.org>
   9  *
  10  * License terms: GNU General Public License (GPL) version 2
  11  */
  12 #ifndef __LINUX_PINCTRL_PINCONF_GENERIC_H
  13 #define __LINUX_PINCTRL_PINCONF_GENERIC_H
  14
  15 /*
  16  * You shouldn't even be able to compile with these enums etc unless you're
  17  * using generic pin config. That is why this is defined out.
  18  */
  19 #ifdef CONFIG_GENERIC_PINCONF
  20
  21 /**
  22  * enum pin_config_param - possible pin configuration parameters
  23  * @PIN_CONFIG_BIAS_DISABLE: disable any pin bias on the pin, a
  24  *      transition from say pull-up to pull-down implies that you disable
  25  *      pull-up in the process, this setting disables all biasing.
  26  * @PIN_CONFIG_BIAS_HIGH_IMPEDANCE: the pin will be set to a high impedance
  27  *      mode, also know as "third-state" (tristate) or "high-Z" or "floating".
  28  *      On output pins this effectively disconnects the pin, which is useful
  29  *      if for example some other pin is going to drive the signal connected
  30  *      to it for a while. Pins used for input are usually always high
  31  *      impedance.
  32  * @PIN_CONFIG_BIAS_BUS_HOLD: the pin will be set to weakly latch so that it
  33  *      weakly drives the last value on a tristate bus, also known as a "bus
  34  *      holder", "bus keeper" or "repeater". This allows another device on the
  35  *      bus to change the value by driving the bus high or low and switching to
  36  *      tristate. The argument is ignored.
  37  * @PIN_CONFIG_BIAS_PULL_UP: the pin will be pulled up (usually with high
  38  *      impedance to VDD). If the argument is != 0 pull-up is enabled,
  39  *      if it is 0, pull-up is disabled.
  40  * @PIN_CONFIG_BIAS_PULL_DOWN: the pin will be pulled down (usually with high
  41  *      impedance to GROUND). If the argument is != 0 pull-down is enabled,
  42  *      if it is 0, pull-down is disabled.
  43  * @PIN_CONFIG_BIAS_PULL_PIN_DEFAULT: the pin will be pulled up or down based
  44  *      on embedded knowledge of the controller, like current mux function.
  45  *      If the argument is != 0 pull up/down is enabled, if it is 0,
  46  *      the pull is disabled.
  47  * @PIN_CONFIG_DRIVE_PUSH_PULL: the pin will be driven actively high and
  48  *      low, this is the most typical case and is typically achieved with two
  49  *      active transistors on the output. Setting this config will enable
  50  *      push-pull mode, the argument is ignored.
  51  * @PIN_CONFIG_DRIVE_OPEN_DRAIN: the pin will be driven with open drain (open
  52  *      collector) which means it is usually wired with other output ports
  53  *      which are then pulled up with an external resistor. Setting this
  54  *      config will enable open drain mode, the argument is ignored.
  55  * @PIN_CONFIG_DRIVE_OPEN_SOURCE: the pin will be driven with open source
  56  *      (open emitter). Setting this config will enable open drain mode, the
  57  *      argument is ignored.
  58  * @PIN_CONFIG_DRIVE_STRENGTH: the pin will sink or source at most the current
  59  *      passed as argument. The argument is in mA.
  60  * @PIN_CONFIG_INPUT_SCHMITT_ENABLE: control schmitt-trigger mode on the pin.
  61  *      If the argument != 0, schmitt-trigger mode is enabled. If it's 0,
  62  *      schmitt-trigger mode is disabled.
  63  * @PIN_CONFIG_INPUT_SCHMITT: this will configure an input pin to run in
  64  *      schmitt-trigger mode. If the schmitt-trigger has adjustable hysteresis,
  65  *      the threshold value is given on a custom format as argument when
  66  *      setting pins to this mode.
  67  * @PIN_CONFIG_INPUT_DEBOUNCE: this will configure the pin to debounce mode,
  68  *      which means it will wait for signals to settle when reading inputs. The
  69  *      argument gives the debounce time on a custom format. Setting the
  70  *      argument to zero turns debouncing off.
  71  * @PIN_CONFIG_POWER_SOURCE: if the pin can select between different power
  72  *      supplies, the argument to this parameter (on a custom format) tells
  73  *      the driver which alternative power source to use.
  74  * @PIN_CONFIG_SLEW_RATE: if the pin can select slew rate, the argument to
  75  *      this parameter (on a custom format) tells the driver which alternative
  76  *      slew rate to use.
  77  * @PIN_CONFIG_LOW_POWER_MODE: this will configure the pin for low power
  78  *      operation, if several modes of operation are supported these can be
  79  *      passed in the argument on a custom form, else just use argument 1
  80  *      to indicate low power mode, argument 0 turns low power mode off.
  81  * @PIN_CONFIG_OUTPUT: this will configure the pin in output, use argument
  82  *      1 to indicate high level, argument 0 to indicate low level.
  83  * @PIN_CONFIG_END: this is the last enumerator for pin configurations, if
  84  *      you need to pass in custom configurations to the pin controller, use
  85  *      PIN_CONFIG_END+1 as the base offset.
  86  */
  87 enum pin_config_param {
  88         PIN_CONFIG_BIAS_DISABLE,
  89         PIN_CONFIG_BIAS_HIGH_IMPEDANCE,
  90         PIN_CONFIG_BIAS_BUS_HOLD,
  91         PIN_CONFIG_BIAS_PULL_UP,
  92         PIN_CONFIG_BIAS_PULL_DOWN,
  93         PIN_CONFIG_BIAS_PULL_PIN_DEFAULT,
  94         PIN_CONFIG_DRIVE_PUSH_PULL,
  95         PIN_CONFIG_DRIVE_OPEN_DRAIN,
  96         PIN_CONFIG_DRIVE_OPEN_SOURCE,
  97         PIN_CONFIG_DRIVE_STRENGTH,
  98         PIN_CONFIG_INPUT_SCHMITT_ENABLE,
  99         PIN_CONFIG_INPUT_SCHMITT,
 100         PIN_CONFIG_INPUT_DEBOUNCE,
 101         PIN_CONFIG_POWER_SOURCE,
 102         PIN_CONFIG_SLEW_RATE,
 103         PIN_CONFIG_LOW_POWER_MODE,
 104         PIN_CONFIG_OUTPUT,
 105         PIN_CONFIG_END = 0x7FFF,
 106 };
 107
 108 /*
 109  * Helpful configuration macro to be used in tables etc.
 110  */
 111 #define PIN_CONF_PACKED(p, a) ((a << 16) | ((unsigned long) p & 0xffffUL))
 112
 113 /*
 114  * The following inlines stuffs a configuration parameter and data value
 115  * into and out of an unsigned long argument, as used by the generic pin config
 116  * system. We put the parameter in the lower 16 bits and the argument in the
 117  * upper 16 bits.
 118  */
 119
 120 static inline enum pin_config_param pinconf_to_config_param(unsigned long config)
 121 {
 122         return (enum pin_config_param) (config & 0xffffUL);
 123 }
 124
 125 static inline u16 pinconf_to_config_argument(unsigned long config)
 126 {
 127         return (enum pin_config_param) ((config >> 16) & 0xffffUL);
 128 }
 129
 130 static inline unsigned long pinconf_to_config_packed(enum pin_config_param param,
 131                                                      u16 argument)
 132 {
 133         return PIN_CONF_PACKED(param, argument);
 134 }
 135
 136 #endif /* CONFIG_GENERIC_PINCONF */
 137
 138 #endif /* __LINUX_PINCTRL_PINCONF_GENERIC_H */