include/linux/spi/ads7846.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* linux/spi/ads7846.h */
   3
   4 /* Touchscreen characteristics vary between boards and models.  The
   5  * platform_data for the device's "struct device" holds this information.
   6  *
   7  * It's OK if the min/max values are zero.
   8  */
   9 enum ads7846_filter {
  10         ADS7846_FILTER_OK,
  11         ADS7846_FILTER_REPEAT,
  12         ADS7846_FILTER_IGNORE,
  13 };
  14
  15 struct ads7846_platform_data {
  16         u16     model;                  /* 7843, 7845, 7846, 7873. */
  17         u16     vref_delay_usecs;       /* 0 for external vref; etc */
  18         u16     vref_mv;                /* external vref value, milliVolts
  19                                          * ads7846: if 0, use internal vref */
  20         bool    keep_vref_on;           /* set to keep vref on for differential
  21                                          * measurements as well */
  22         bool    swap_xy;                /* swap x and y axes */
  23
  24         /* Settling time of the analog signals; a function of Vcc and the
  25          * capacitance on the X/Y drivers.  If set to non-zero, two samples
  26          * are taken with settle_delay us apart, and the second one is used.
  27          * ~150 uSec with 0.01uF caps.
  28          */
  29         u16     settle_delay_usecs;
  30
  31         /* If set to non-zero, after samples are taken this delay is applied
  32          * and penirq is rechecked, to help avoid false events.  This value
  33          * is affected by the material used to build the touch layer.
  34          */
  35         u16     penirq_recheck_delay_usecs;
  36
  37         u16     x_plate_ohms;
  38         u16     y_plate_ohms;
  39
  40         u16     x_min, x_max;
  41         u16     y_min, y_max;
  42         u16     pressure_min, pressure_max;
  43
  44         u16     debounce_max;           /* max number of additional readings
  45                                          * per sample */
  46         u16     debounce_tol;           /* tolerance used for filtering */
  47         u16     debounce_rep;           /* additional consecutive good readings
  48                                          * required after the first two */
  49         int     gpio_pendown;           /* the GPIO used to decide the pendown
  50                                          * state if get_pendown_state == NULL */
  51         int     gpio_pendown_debounce;  /* platform specific debounce time for
  52                                          * the gpio_pendown */
  53         int     (*get_pendown_state)(void);
  54         int     (*filter_init)  (const struct ads7846_platform_data *pdata,
  55                                  void **filter_data);
  56         int     (*filter)       (void *filter_data, int data_idx, int *val);
  57         void    (*filter_cleanup)(void *filter_data);
  58         void    (*wait_for_sync)(void);
  59         bool    wakeup;
  60         unsigned long irq_flags;
  61 };
  62