firmware/export/mpr121.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2012 Amaury Pouly
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21
  22 /** Driver for the Freescale MPR121 Capacitive Proximity Sensor */
  23 #include "system.h"
  24
  25 #define ELECTRODE_COUNT 12
  26 #define ELE_GPIO_FIRST  4
  27 #define ELE_GPIO_LAST   11
  28
  29 /* gpio config (encoding: [0]=en,[1]=dir,[2]=ctl[1],[3]=ctl[0]) */
  30 #define ELE_GPIO_DISABLE        0
  31 #define ELE_GPIO_INPUT          1
  32 #define ELE_GPIO_INPUT_PULLDOWN 9 /* input with pull-down */
  33 #define ELE_GPIO_INPUT_PULLUP   13 /* input with pull-up */
  34 #define ELE_GPIO_OUTPUT         3
  35 #define ELE_GPIO_OUTPUT_OPEN     11 /* open drain low-side */
  36 #define ELE_GPIO_OUTPUT_OPEN_LED 15 /* open drain high-side (led driver) */
  37
  38 /* internal use */
  39 #define ELE_GPIO_EN(val)    ((val) & 1)
  40 #define ELE_GPIO_DIR(val)   (((val) >> 1) & 1)
  41 #define ELE_GPIO_CTL0(val)  (((val) >> 3) & 1)
  42 #define ELE_GPIO_CTL1(val)  (((val) >> 1) & 1)
  43
  44 struct mpr121_electrode_config_t
  45 {
  46     uint8_t bv; /* baseline value */
  47     uint8_t tth; /* touch threshold */
  48     uint8_t rth; /* release threshold */
  49     uint8_t cdc; /* charge current (optional if auto-conf) */
  50     uint8_t cdt; /* charge time (optional if auto-conf) */
  51     int gpio; /* gpio config */
  52 };
  53
  54 struct mpr121_baseline_filter_config_t
  55 {
  56     uint8_t mhd; /* max half delta (except for touched) */
  57     uint8_t nhd; /* noise half delta */
  58     uint8_t ncl; /* noise count limit */
  59     uint8_t fdl; /* filter delay count limit */
  60 };
  61
  62 struct mpr121_baseline_filters_config_t
  63 {
  64     struct mpr121_baseline_filter_config_t rising;
  65     struct mpr121_baseline_filter_config_t falling;
  66     struct mpr121_baseline_filter_config_t touched;
  67 };
  68
  69 struct mpr121_debounce_config_t
  70 {
  71     uint8_t dt; /* debounce count for touch */
  72     uint8_t dr; /* debounce count for release */
  73 };
  74
  75 /* first filter iterations */
  76 #define FFI_6_SAMPLES   0
  77 #define FFI_10_SAMPLES  1
  78 #define FFI_18_SAMPLES  2
  79 #define FFI_34_SAMPLES  3
  80 /* charge discharge current */
  81 #define CDC_DISABLE     0
  82 #define CDC_uA(ua)      (ua)
  83 /* charge discharge time */
  84 #define CDT_DISABLE     0
  85 #define CDT_log_us(lus) (lus) /* actual value = 2^{us-2} µs */
  86 /* second filter iterations */
  87 #define SFI_4_SAMPLES   0
  88 #define SFI_6_SAMPLES   1
  89 #define SFI_10_SAMPLES  2
  90 #define SFI_18_SAMPLES  3
  91 /* Eletrode sample interval */
  92 #define ESI_log_ms(lms) (lms) /* actual value = 2^{lms} ms */
  93
  94 struct mpr121_global_config_t
  95 {
  96     uint8_t ffi; /* first filter iterations */
  97     uint8_t cdc; /* global charge discharge current */
  98     uint8_t cdt; /* global charge discharge time */
  99     uint8_t sfi; /* second first iterations */
 100     uint8_t esi; /* electrode sample interval */
 101 };
 102
 103 #define RETRY_NEVER     0
 104 #define RETRY_2_TIMES   1
 105 #define RETRY_4_TIMES   2
 106 #define RETRY_8_TIMES   3
 107
 108 struct mpr121_auto_config_t
 109 {
 110     bool en; /* auto-conf enable */
 111     bool ren; /* auto-reconf enable */
 112     uint8_t retry; /* retry count */
 113     bool scts; /* skip charge time search */
 114     uint8_t usl; /* upper-side limit */
 115     uint8_t lsl; /* lower-side limit */
 116     uint8_t tl; /* target level */
 117     bool acfie; /* auto-conf fail interrupt en */
 118     bool arfie; /* auto-reconf fail interrupt en */
 119     bool oorie; /* out of range interrupt en */
 120 };
 121
 122 /* electrode mode */
 123 #define ELE_DISABLE     0
 124 #define ELE_EN0_x(x)    ((x) + 1)
 125 /* eleprox mode */
 126 #define ELEPROX_DISABLE 0
 127 #define ELEPROX_EN0_1   1
 128 #define ELEPROX_EN0_3   2
 129 #define ELEPROX_EN0_11  3
 130 /* calibration lock */
 131 #define CL_SLOW_TRACK   0
 132 #define CL_DISABLE      1
 133 #define CL_TRACK        2
 134 #define CL_FAST_TRACK   3
 135
 136 struct mpr121_config_t
 137 {
 138     struct mpr121_electrode_config_t ele[ELECTRODE_COUNT];
 139     struct mpr121_electrode_config_t eleprox;
 140     struct
 141     {
 142         struct mpr121_baseline_filters_config_t ele;
 143         struct mpr121_baseline_filters_config_t eleprox;
 144     }filters;
 145     struct mpr121_debounce_config_t debounce;
 146     struct mpr121_global_config_t global;
 147     struct mpr121_auto_config_t autoconf;
 148     uint8_t ele_en; /* eletroce mode */
 149     uint8_t eleprox_en; /* proximity mode */
 150     uint8_t cal_lock; /* calibration lock */
 151 };
 152
 153 /* gpio value */
 154 #define ELE_GPIO_CLR    0
 155 #define ELE_GPIO_SET    1
 156 #define ELE_GPIO_TOG    2
 157 /* pwm value */
 158 #define ELE_PWM_DISABLE 0
 159 #define ELE_PWM_DUTY(x) (x)
 160 #define ELE_PWM_MIN_DUTY    1
 161 #define ELE_PWM_MAX_DUTY    15
 162
 163 int mpr121_init(int dev_i2c_addr);
 164 int mpr121_soft_reset(void);
 165 int mpr121_set_config(struct mpr121_config_t *conf);
 166 /* gpios are only implemented for electrode>=4 */
 167 int mpr121_set_gpio_output(int ele, int gpio_val);
 168 int mpr121_set_gpio_pwm(int ele, int pwm);
 169 /* get electrode status (bitmap) */
 170 int mpr121_get_touch_status(unsigned *status);