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         u16     vref_mv;                /* external vref value, milliVolts */
  18         bool    keep_vref_on;           /* set to keep vref on for differential
  19                                          * measurements as well */
  20
  21         /* Settling time of the analog signals; a function of Vcc and the
  22          * capacitance on the X/Y drivers.  If set to non-zero, two samples
  23          * are taken with settle_delay us apart, and the second one is used.
  24          * ~150 uSec with 0.01uF caps.
  25          */
  26         u16     settle_delay_usecs;
  27
  28         /* If set to non-zero, after samples are taken this delay is applied
  29          * and penirq is rechecked, to help avoid false events.  This value
  30          * is affected by the material used to build the touch layer.
  31          */
  32         u16     penirq_recheck_delay_usecs;
  33
  34         u16     x_plate_ohms;
  35         u16     y_plate_ohms;
  36
  37         u16     x_min, x_max;
  38         u16     y_min, y_max;
  39         u16     pressure_min, pressure_max;
  40
  41         u16     debounce_max;           /* max number of additional readings
  42                                          * per sample */
  43         u16     debounce_tol;           /* tolerance used for filtering */
  44         u16     debounce_rep;           /* additional consecutive good readings
  45                                          * required after the first two */
  46         int     gpio_pendown;           /* the GPIO used to decide the pendown
  47                                          * state if get_pendown_state == NULL
  48                                          */
  49         int     (*get_pendown_state)(void);
  50         int     (*filter_init)  (struct ads7846_platform_data *pdata,
  51                                  void **filter_data);
  52         int     (*filter)       (void *filter_data, int data_idx, int *val);
  53         void    (*filter_cleanup)(void *filter_data);
  54 };
  55