include/linux/spi/ads7846.h

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