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  * enum pin_config_param - possible pin configuration parameters
  17  * @PIN_CONFIG_BIAS_BUS_HOLD: the pin will be set to weakly latch so that it
  18  *      weakly drives the last value on a tristate bus, also known as a "bus
  19  *      holder", "bus keeper" or "repeater". This allows another device on the
  20  *      bus to change the value by driving the bus high or low and switching to
  21  *      tristate. The argument is ignored.
  22  * @PIN_CONFIG_BIAS_DISABLE: disable any pin bias on the pin, a
  23  *      transition from say pull-up to pull-down implies that you disable
  24  *      pull-up in the process, this setting disables all biasing.
  25  * @PIN_CONFIG_BIAS_HIGH_IMPEDANCE: the pin will be set to a high impedance
  26  *      mode, also know as "third-state" (tristate) or "high-Z" or "floating".
  27  *      On output pins this effectively disconnects the pin, which is useful
  28  *      if for example some other pin is going to drive the signal connected
  29  *      to it for a while. Pins used for input are usually always high
  30  *      impedance.
  31  * @PIN_CONFIG_BIAS_PULL_DOWN: the pin will be pulled down (usually with high
  32  *      impedance to GROUND). If the argument is != 0 pull-down is enabled,
  33  *      if it is 0, pull-down is total, i.e. the pin is connected to GROUND.
  34  * @PIN_CONFIG_BIAS_PULL_PIN_DEFAULT: the pin will be pulled up or down based
  35  *      on embedded knowledge of the controller hardware, like current mux
  36  *      function. The pull direction and possibly strength too will normally
  37  *      be decided completely inside the hardware block and not be readable
  38  *      from the kernel side.
  39  *      If the argument is != 0 pull up/down is enabled, if it is 0, the
  40  *      configuration is ignored. The proper way to disable it is to use
  41  *      @PIN_CONFIG_BIAS_DISABLE.
  42  * @PIN_CONFIG_BIAS_PULL_UP: the pin will be pulled up (usually with high
  43  *      impedance to VDD). If the argument is != 0 pull-up is enabled,
  44  *      if it is 0, pull-up is total, i.e. the pin is connected to VDD.
  45  * @PIN_CONFIG_DRIVE_OPEN_DRAIN: the pin will be driven with open drain (open
  46  *      collector) which means it is usually wired with other output ports
  47  *      which are then pulled up with an external resistor. Setting this
  48  *      config will enable open drain mode, the argument is ignored.
  49  * @PIN_CONFIG_DRIVE_OPEN_SOURCE: the pin will be driven with open source
  50  *      (open emitter). Setting this config will enable open source mode, the
  51  *      argument is ignored.
  52  * @PIN_CONFIG_DRIVE_PUSH_PULL: the pin will be driven actively high and
  53  *      low, this is the most typical case and is typically achieved with two
  54  *      active transistors on the output. Setting this config will enable
  55  *      push-pull mode, the argument is ignored.
  56  * @PIN_CONFIG_DRIVE_STRENGTH: the pin will sink or source at most the current
  57  *      passed as argument. The argument is in mA.
  58  * @PIN_CONFIG_INPUT_DEBOUNCE: this will configure the pin to debounce mode,
  59  *      which means it will wait for signals to settle when reading inputs. The
  60  *      argument gives the debounce time in usecs. Setting the
  61  *      argument to zero turns debouncing off.
  62  * @PIN_CONFIG_INPUT_ENABLE: enable the pin's input.  Note that this does not
  63  *      affect the pin's ability to drive output.  1 enables input, 0 disables
  64  *      input.
  65  * @PIN_CONFIG_INPUT_SCHMITT: this will configure an input pin to run in
  66  *      schmitt-trigger mode. If the schmitt-trigger has adjustable hysteresis,
  67  *      the threshold value is given on a custom format as argument when
  68  *      setting pins to this mode.
  69  * @PIN_CONFIG_INPUT_SCHMITT_ENABLE: control schmitt-trigger mode on the pin.
  70  *      If the argument != 0, schmitt-trigger mode is enabled. If it's 0,
  71  *      schmitt-trigger mode is disabled.
  72  * @PIN_CONFIG_LOW_POWER_MODE: this will configure the pin for low power
  73  *      operation, if several modes of operation are supported these can be
  74  *      passed in the argument on a custom form, else just use argument 1
  75  *      to indicate low power mode, argument 0 turns low power mode off.
  76  * @PIN_CONFIG_OUTPUT_ENABLE: this will enable the pin's output mode
  77  *      without driving a value there. For most platforms this reduces to
  78  *      enable the output buffers and then let the pin controller current
  79  *      configuration (eg. the currently selected mux function) drive values on
  80  *      the line. Use argument 1 to enable output mode, argument 0 to disable
  81  *      it.
  82  * @PIN_CONFIG_OUTPUT: this will configure the pin as an output and drive a
  83  *      value on the line. Use argument 1 to indicate high level, argument 0 to
  84  *      indicate low level. (Please see Documentation/driver-api/pinctl.rst,
  85  *      section "GPIO mode pitfalls" for a discussion around this parameter.)
  86  * @PIN_CONFIG_POWER_SOURCE: if the pin can select between different power
  87  *      supplies, the argument to this parameter (on a custom format) tells
  88  *      the driver which alternative power source to use.
  89  * @PIN_CONFIG_SLEW_RATE: if the pin can select slew rate, the argument to
  90  *      this parameter (on a custom format) tells the driver which alternative
  91  *      slew rate to use.
  92  * @PIN_CONFIG_END: this is the last enumerator for pin configurations, if
  93  *      you need to pass in custom configurations to the pin controller, use
  94  *      PIN_CONFIG_END+1 as the base offset.
  95  * @PIN_CONFIG_MAX: this is the maximum configuration value that can be
  96  *      presented using the packed format.
  97  */
  98 enum pin_config_param {
  99         PIN_CONFIG_BIAS_BUS_HOLD,
 100         PIN_CONFIG_BIAS_DISABLE,
 101         PIN_CONFIG_BIAS_HIGH_IMPEDANCE,
 102         PIN_CONFIG_BIAS_PULL_DOWN,
 103         PIN_CONFIG_BIAS_PULL_PIN_DEFAULT,
 104         PIN_CONFIG_BIAS_PULL_UP,
 105         PIN_CONFIG_DRIVE_OPEN_DRAIN,
 106         PIN_CONFIG_DRIVE_OPEN_SOURCE,
 107         PIN_CONFIG_DRIVE_PUSH_PULL,
 108         PIN_CONFIG_DRIVE_STRENGTH,
 109         PIN_CONFIG_INPUT_DEBOUNCE,
 110         PIN_CONFIG_INPUT_ENABLE,
 111         PIN_CONFIG_INPUT_SCHMITT,
 112         PIN_CONFIG_INPUT_SCHMITT_ENABLE,
 113         PIN_CONFIG_LOW_POWER_MODE,
 114         PIN_CONFIG_OUTPUT_ENABLE,
 115         PIN_CONFIG_OUTPUT,
 116         PIN_CONFIG_POWER_SOURCE,
 117         PIN_CONFIG_SLEW_RATE,
 118         PIN_CONFIG_END = 0x7F,
 119         PIN_CONFIG_MAX = 0xFF,
 120 };
 121
 122 /*
 123  * Helpful configuration macro to be used in tables etc.
 124  */
 125 #define PIN_CONF_PACKED(p, a) ((a << 8) | ((unsigned long) p & 0xffUL))
 126
 127 /*
 128  * The following inlines stuffs a configuration parameter and data value
 129  * into and out of an unsigned long argument, as used by the generic pin config
 130  * system. We put the parameter in the lower 8 bits and the argument in the
 131  * upper 24 bits.
 132  */
 133
 134 static inline enum pin_config_param pinconf_to_config_param(unsigned long config)
 135 {
 136         return (enum pin_config_param) (config & 0xffUL);
 137 }
 138
 139 static inline u32 pinconf_to_config_argument(unsigned long config)
 140 {
 141         return (u32) ((config >> 8) & 0xffffffUL);
 142 }
 143
 144 static inline unsigned long pinconf_to_config_packed(enum pin_config_param param,
 145                                                      u32 argument)
 146 {
 147         return PIN_CONF_PACKED(param, argument);
 148 }
 149
 150 #ifdef CONFIG_GENERIC_PINCONF
 151
 152 #ifdef CONFIG_DEBUG_FS
 153 #define PCONFDUMP(a, b, c, d) {                                 \
 154         .param = a, .display = b, .format = c, .has_arg = d     \
 155         }
 156
 157 struct pin_config_item {
 158         const enum pin_config_param param;
 159         const char * const display;
 160         const char * const format;
 161         bool has_arg;
 162 };
 163 #endif /* CONFIG_DEBUG_FS */
 164
 165 #ifdef CONFIG_OF
 166
 167 #include <linux/device.h>
 168 #include <linux/pinctrl/machine.h>
 169 struct pinctrl_dev;
 170 struct pinctrl_map;
 171
 172 struct pinconf_generic_params {
 173         const char * const property;
 174         enum pin_config_param param;
 175         u32 default_value;
 176 };
 177
 178 int pinconf_generic_dt_subnode_to_map(struct pinctrl_dev *pctldev,
 179                 struct device_node *np, struct pinctrl_map **map,
 180                 unsigned *reserved_maps, unsigned *num_maps,
 181                 enum pinctrl_map_type type);
 182 int pinconf_generic_dt_node_to_map(struct pinctrl_dev *pctldev,
 183                 struct device_node *np_config, struct pinctrl_map **map,
 184                 unsigned *num_maps, enum pinctrl_map_type type);
 185 void pinconf_generic_dt_free_map(struct pinctrl_dev *pctldev,
 186                 struct pinctrl_map *map, unsigned num_maps);
 187
 188 static inline int pinconf_generic_dt_node_to_map_group(
 189                 struct pinctrl_dev *pctldev, struct device_node *np_config,
 190                 struct pinctrl_map **map, unsigned *num_maps)
 191 {
 192         return pinconf_generic_dt_node_to_map(pctldev, np_config, map, num_maps,
 193                         PIN_MAP_TYPE_CONFIGS_GROUP);
 194 }
 195
 196 static inline int pinconf_generic_dt_node_to_map_pin(
 197                 struct pinctrl_dev *pctldev, struct device_node *np_config,
 198                 struct pinctrl_map **map, unsigned *num_maps)
 199 {
 200         return pinconf_generic_dt_node_to_map(pctldev, np_config, map, num_maps,
 201                         PIN_MAP_TYPE_CONFIGS_PIN);
 202 }
 203
 204 static inline int pinconf_generic_dt_node_to_map_all(
 205                 struct pinctrl_dev *pctldev, struct device_node *np_config,
 206                 struct pinctrl_map **map, unsigned *num_maps)
 207 {
 208         /*
 209          * passing the type as PIN_MAP_TYPE_INVALID causes the underlying parser
 210          * to infer the map type from the DT properties used.
 211          */
 212         return pinconf_generic_dt_node_to_map(pctldev, np_config, map, num_maps,
 213                         PIN_MAP_TYPE_INVALID);
 214 }
 215 #endif
 216
 217 #endif /* CONFIG_GENERIC_PINCONF */
 218
 219 #endif /* __LINUX_PINCTRL_PINCONF_GENERIC_H */