diff options
Diffstat (limited to 'drivers/input/touch-overlay.c')
| -rw-r--r-- | drivers/input/touch-overlay.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/drivers/input/touch-overlay.c b/drivers/input/touch-overlay.c new file mode 100644 index 000000000000..8806373f7a4a --- /dev/null +++ b/drivers/input/touch-overlay.c @@ -0,0 +1,277 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Helper functions for overlay objects on touchscreens + * + * Copyright (c) 2023 Javier Carrasco <javier.carrasco@wolfvision.net> + */ + +#include <linux/input.h> +#include <linux/input/mt.h> +#include <linux/input/touch-overlay.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/property.h> + +struct touch_overlay_segment { + struct list_head list; + u32 x_origin; + u32 y_origin; + u32 x_size; + u32 y_size; + u32 key; + bool pressed; + int slot; +}; + +static int touch_overlay_get_segment(struct fwnode_handle *segment_node, + struct touch_overlay_segment *segment, + struct input_dev *input) +{ + int error; + + error = fwnode_property_read_u32(segment_node, "x-origin", + &segment->x_origin); + if (error) + return error; + + error = fwnode_property_read_u32(segment_node, "y-origin", + &segment->y_origin); + if (error) + return error; + + error = fwnode_property_read_u32(segment_node, "x-size", + &segment->x_size); + if (error) + return error; + + error = fwnode_property_read_u32(segment_node, "y-size", + &segment->y_size); + if (error) + return error; + + error = fwnode_property_read_u32(segment_node, "linux,code", + &segment->key); + if (!error) + input_set_capability(input, EV_KEY, segment->key); + else if (error != -EINVAL) + return error; + + return 0; +} + +/** + * touch_overlay_map - map overlay objects from the device tree and set + * key capabilities if buttons are defined. + * @list: pointer to the list that will hold the segments + * @input: pointer to the already allocated input_dev + * + * Returns 0 on success and error number otherwise. + * + * If buttons are defined, key capabilities are set accordingly. + */ +int touch_overlay_map(struct list_head *list, struct input_dev *input) +{ + struct fwnode_handle *fw_segment; + struct device *dev = input->dev.parent; + struct touch_overlay_segment *segment; + int error; + + struct fwnode_handle *overlay __free(fwnode_handle) = + device_get_named_child_node(dev, "touch-overlay"); + if (!overlay) + return 0; + + fwnode_for_each_available_child_node(overlay, fw_segment) { + segment = devm_kzalloc(dev, sizeof(*segment), GFP_KERNEL); + if (!segment) { + fwnode_handle_put(fw_segment); + return -ENOMEM; + } + error = touch_overlay_get_segment(fw_segment, segment, input); + if (error) { + fwnode_handle_put(fw_segment); + return error; + } + list_add_tail(&segment->list, list); + } + + return 0; +} +EXPORT_SYMBOL(touch_overlay_map); + +/** + * touch_overlay_get_touchscreen_abs - get abs size from the touchscreen area. + * @list: pointer to the list that holds the segments + * @x: horizontal abs + * @y: vertical abs + */ +void touch_overlay_get_touchscreen_abs(struct list_head *list, u16 *x, u16 *y) +{ + struct touch_overlay_segment *segment; + struct list_head *ptr; + + list_for_each(ptr, list) { + segment = list_entry(ptr, struct touch_overlay_segment, list); + if (!segment->key) { + *x = segment->x_size - 1; + *y = segment->y_size - 1; + break; + } + } +} +EXPORT_SYMBOL(touch_overlay_get_touchscreen_abs); + +static bool touch_overlay_segment_event(struct touch_overlay_segment *seg, + struct input_mt_pos *pos) +{ + if (pos->x >= seg->x_origin && pos->x < (seg->x_origin + seg->x_size) && + pos->y >= seg->y_origin && pos->y < (seg->y_origin + seg->y_size)) + return true; + + return false; +} + +/** + * touch_overlay_mapped_touchscreen - check if a touchscreen area is mapped + * @list: pointer to the list that holds the segments + * + * Returns true if a touchscreen area is mapped or false otherwise. + */ +bool touch_overlay_mapped_touchscreen(struct list_head *list) +{ + struct touch_overlay_segment *segment; + struct list_head *ptr; + + list_for_each(ptr, list) { + segment = list_entry(ptr, struct touch_overlay_segment, list); + if (!segment->key) + return true; + } + + return false; +} +EXPORT_SYMBOL(touch_overlay_mapped_touchscreen); + +static bool touch_overlay_event_on_ts(struct list_head *list, + struct input_mt_pos *pos) +{ + struct touch_overlay_segment *segment; + struct list_head *ptr; + + list_for_each(ptr, list) { + segment = list_entry(ptr, struct touch_overlay_segment, list); + if (segment->key) + continue; + + if (touch_overlay_segment_event(segment, pos)) { + pos->x -= segment->x_origin; + pos->y -= segment->y_origin; + return true; + } + /* ignore touch events outside the defined area */ + return false; + } + + return true; +} + +static bool touch_overlay_button_event(struct input_dev *input, + struct touch_overlay_segment *segment, + struct input_mt_pos *pos, int slot) +{ + struct input_mt *mt = input->mt; + struct input_mt_slot *s = &mt->slots[slot]; + bool button_contact = touch_overlay_segment_event(segment, pos); + + if (segment->slot == slot && segment->pressed) { + /* sliding out of the button releases it */ + if (!button_contact) { + input_report_key(input, segment->key, false); + segment->pressed = false; + /* keep available for a possible touch event */ + return false; + } + /* ignore sliding on the button while pressed */ + s->frame = mt->frame; + return true; + } else if (button_contact) { + input_report_key(input, segment->key, true); + s->frame = mt->frame; + segment->slot = slot; + segment->pressed = true; + return true; + } + + return false; +} + +/** + * touch_overlay_sync_frame - update the status of the segments and report + * buttons whose tracked slot is unused. + * @list: pointer to the list that holds the segments + * @input: pointer to the input device associated to the contact + */ +void touch_overlay_sync_frame(struct list_head *list, struct input_dev *input) +{ + struct touch_overlay_segment *segment; + struct input_mt *mt = input->mt; + struct input_mt_slot *s; + struct list_head *ptr; + + list_for_each(ptr, list) { + segment = list_entry(ptr, struct touch_overlay_segment, list); + if (!segment->key) + continue; + + s = &mt->slots[segment->slot]; + if (!input_mt_is_used(mt, s) && segment->pressed) { + input_report_key(input, segment->key, false); + segment->pressed = false; + } + } +} +EXPORT_SYMBOL(touch_overlay_sync_frame); + +/** + * touch_overlay_process_contact - process contacts according to the overlay + * mapping. This function acts as a filter to release the calling driver + * from the contacts that are either related to overlay buttons or out of the + * overlay touchscreen area, if defined. + * @list: pointer to the list that holds the segments + * @input: pointer to the input device associated to the contact + * @pos: pointer to the contact position + * @slot: slot associated to the contact (0 if multitouch is not supported) + * + * Returns true if the contact was processed (reported for valid key events + * and dropped for contacts outside the overlay touchscreen area) or false + * if the contact must be processed by the caller. In that case this function + * shifts the (x,y) coordinates to the overlay touchscreen axis if required. + */ +bool touch_overlay_process_contact(struct list_head *list, + struct input_dev *input, + struct input_mt_pos *pos, int slot) +{ + struct touch_overlay_segment *segment; + struct list_head *ptr; + + /* + * buttons must be prioritized over overlay touchscreens to account for + * overlappings e.g. a button inside the touchscreen area. + */ + list_for_each(ptr, list) { + segment = list_entry(ptr, struct touch_overlay_segment, list); + if (segment->key && + touch_overlay_button_event(input, segment, pos, slot)) + return true; + } + + /* + * valid contacts on the overlay touchscreen are left for the client + * to be processed/reported according to its (possibly) unique features. + */ + return !touch_overlay_event_on_ts(list, pos); +} +EXPORT_SYMBOL(touch_overlay_process_contact); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Helper functions for overlay objects on touch devices"); |