Cannot configure touch interrupt pin without modifying BSP files (BSP-711)

[TT-Qt]

Issue:
Currently the touch interrupt pin comes directly from the board's header like this:

esp-bsp/bsp/esp32_p4_function_ev_board/include/bsp/esp32_p4_function_ev_board.h

Line 97 in 317ff05

#define BSP_LCD_TOUCH_INT (GPIO_NUM_NC)

Here the pin is marked as 'not connected'. To modify this you'll need to modify BSP header-files which is not wanted in our case.

Suggestion:
Add support to set custom touch pin via bsp_touch_config_t:

For example:

typedef struct {
    gpio_num_t int_gpio_num;    /*!< GPIO number of interrupt pin */
} bsp_touch_config_t;

This also requires some flag or using the given pin num to detect whether default value or custom value should be used.

[github-actions]

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Thanks for the suggestion — it makes sense.

From the BSP development guide, touch HW init is expected to be exposed via bsp/touch.h with a function:

esp_err_t bsp_touch_new(const bsp_touch_config_t *config, esp_lcd_touch_handle_t *ret_touch);

and BSPs should allow configuration through such structures rather than requiring edits to board headers (which mainly list default capabilities/pinouts) (BSP development guide). This aligns with your proposal to pass a custom interrupt GPIO via bsp_touch_config_t.

In the current esp32_p4_function_ev_board noglib API, bsp_touch_config_t is defined, but the macros show BSP_LCD_TOUCH_INT as GPIO_NUM_NC, i.e., not connected, which forces use of the board header defaults (esp32_p4_function_ev_board (noglib) Macros, API functions incl. bsp_touch_new). The generic BSP also documents enabling touch and selecting drivers via Kconfig, but doesn’t cover overriding INT via runtime config (esp_bsp_generic README).

Suggestion we can implement:

• Extend bsp_touch_config_t to include an optional interrupt GPIO (and, if needed, reset GPIO), e.g.:

  typedef struct {
      gpio_num_t int_gpio_num;   // set to GPIO_NUM_NC to use board default
      gpio_num_t rst_gpio_num;   // optional, same rule
      // other existing fields...
  } bsp_touch_config_t;
  

• In bsp_touch_new(), if int_gpio_num != GPIO_NUM_NC, use it; otherwise fall back to BSP_LCD_TOUCH_INT from the board header. This mirrors how BSPs commonly allow runtime override while preserving defaults (BSP development guide).

This change would let users avoid modifying BSP headers while remaining backward compatible (users not providing int_gpio_num keep current behavior). If you’d like, I can open a PR proposal reflecting the above.

[espzav]

Hi @TT-Qt,
usually the BSP is related to the specific board (with LCD, audio and other features). Pins are defined and they are not changing anymore. This BSP is spicific, but we want to keep same API.
The best way is copy BSP to local and made changes for your specific board.

[TT-Qt]

Hi @espzav. I understand this point as well and the developers are free to customize the BSP that is located in their project which they have exported from the GUI application. I also understand that the suggested change would require bigger changes to existing BSPs.

The original idea was to give a bit more control for the GUI platform adaptation to utilize touch also on boards that support it but do not have a dedicated pin for it by default.

One option would be to tie some pin for the touch interrupt also on the esp_p4_function_ev_board in the BSP. What do you think about that?

[qsaramo]

The best way is copy BSP to local and made changes for your specific board.

Well in case of using custom HW this is the way of doint it, but when using the kit as is, without any custom HW, IMHO it would be best to have some PIN selected for touch INT by default so there would not be need to create custom BSP just for using the touch interrupt.

One option would be to tie some pin for the touch interrupt also on the esp_p4_function_ev_board in the BSP. What do you think about that?

This would be the easy way without any bigger API changes.

For example let's select GPIO 47. It is not used in 1.5.2 & 1.4 boards. It's available in connector J1 near the other pins used for connecting to the display board. DuPont wires bundled in the kit have one wire free, so event that's not a problem.

I would have made PR by my self, but as this needs documentation change, and my Chinese is not so good :D, I skipped this idea.

So what this needs is:

• Select touch INT pin here
  • #define BSP_LCD_TOUCH_INT (GPIO_NUM_47)
• Bump BSP version number
• Change documentation for both languages

And this should not affect users who are not willing to use interrupts with touch controller.

So @espzav, how does it sound?