veikk.h

/*
 * Veikk S640 (and others) driver tablet -- still in production
 * Heavily guided by the Wacom driver (drivers/hid/wacom*)
 * @author Jonathan Lam <jlam55555@gmail.com>
 */

#ifndef VEIKK_H
#define VEIKK_H

#include <linux/hid.h>
#include <linux/input.h>
#include <linux/types.h>
#include <linux/usb.h>

#define VEIKK_VENDOR_ID         0x2FEB

#define VEIKK_DRIVER_VERSION    "2.0"
#define VEIKK_DRIVER_AUTHOR     "Jonathan Lam <jlam55555@gmail.com>"
#define VEIKK_DRIVER_DESC       "USB VEIKK drawing tablet driver"
#define VEIKK_DRIVER_LICENSE    "GPL"

#define VEIKK_PEN_REPORT        0x0001
#define VEIKK_STYLUS_REPORT     0x0002  // equivalent to pen report

// supported module parameter types
// TODO: currently not used; may remove in future; however, is used in the
//       configuration tool
enum veikk_modparm {
    VEIKK_MP_SCREEN_MAP,
    VEIKK_MP_SCREEN_SIZE,
    VEIKK_MP_PRESSURE_MAP,
    VEIKK_MP_ORIENTATION
};

// generic struct for representing rectangular geometries (physical/mappings)
// currently only used for
struct veikk_rect {
    s32 x, y;
    u32 width, height;
};

// structure of module parameters (module parameters are just integer-serialized
// versions of these structs); used to easily deserialize module parameters,
// but easier and more consistent to represent everything with struct veikk_rect
// for general use
struct veikk_screen_size {
    u16 width, height;
};
struct veikk_screen_map {
    s16 x, y;
    u16 width, height;
};
struct veikk_pressure_map {
    s16 a0, a1, a2, a3;
};
enum veikk_orientation {
    VEIKK_OR_DFL=0,
    VEIKK_OR_CCW,
    VEIKK_OR_FLIP,
    VEIKK_OR_CW
};

// pen input report -- structure of input report from tablet
struct veikk_pen_report {
    u8 report_id;
    u8 buttons;
    u16 x, y, pressure;
};

// device-specific properties; one created for every device. These
// characteristics should not be modified anywhere in the program; any
// modifiable properties (e.g., mapped characteristics) should be copied
// over to the device's struct veikk before modifying
struct veikk;
struct veikk_device_info {
    // identifiers
    const char *name;
    const int prod_id;

    // physical characteristics; acts as defaults for mapped characteristics
    const int x_max, y_max, pressure_max;

    // device-specific handlers
    int (*alloc_input_devs)(struct veikk *veikk);
    int (*setup_and_register_input_devs)(struct veikk *veikk);
    int (*handle_raw_data)(struct veikk *veikk, u8 *data, int size,
                           unsigned int report_id);
    int (*handle_modparm_change)(struct veikk *veikk);
};

// common properties for veikk devices
struct veikk {
    // hardware details
    struct hid_device *hdev;

    // device-specific properties
    const struct veikk_device_info *vdinfo;

    // mapped digitizer characteristics; initialized with defaults from
    // struct veikk_device_info
    struct veikk_rect map_rect;
    int pressure_map[4];
    // these are used for orientation mapping
    int x_map_axis, y_map_axis, x_map_dir, y_map_dir;

    struct input_dev *pen_input;
    struct list_head lh;
};

// from veikk_drv.c
extern struct list_head vdevs;
extern struct mutex vdevs_mutex;
int veikk_input_open(struct input_dev *dev);
void veikk_input_close(struct input_dev *dev);

// from veikk_vdev.c
extern const struct hid_device_id veikk_ids[];

// from veikk_modparms.c
extern struct veikk_rect veikk_screen_map;
extern struct veikk_rect veikk_screen_size;
extern enum veikk_orientation veikk_orientation;
extern struct veikk_pressure_map veikk_pressure_map;

// module parameter (configuration) helper
void veikk_configure_input_devs(struct veikk_rect ss,
                                struct veikk_rect sm,
                                enum veikk_orientation or,
                                struct veikk *veikk);

// calculate pressure map -- for use in raw_event handler
int veikk_map_pressure(s64 pres, s64 pres_max,
                       struct veikk_pressure_map *coef);
#endif