fix esp32s3 compile error when xclk set to -1

[Kevincoooool]

when i set xclk=-1,complie error

[me-no-dev]

Please add proper title and explanation on why this change is necessary. Does it have to do with camera with their own XCLK?

[Kevincoooool]

Please add proper title and explanation on why this change is necessary. Does it have to do with camera with their own XCLK?

The XCLK pin of the camera on my own hardware uses an active crystal oscillator, and is not controlled by the IO port. When I set it to -1, because the XCLK is not judged in the program, an error will be reported.

[me-no-dev]

OK, then same check should be added here so other chips behave the same :)

[Kevincoooool]

OK, then same check should be added here so other chips behave the same :)

Only ESP32S3 needs it, other chips have judgment

[me-no-dev]

Only ESP32S3 needs it, other chips have judgment

I'm not sure I understand what you mean? Are you saying that the other chips will work fine with -1? I do not see a check for that.

[lovyan03]

@Kevincoooool
Thanks for this pull request suggestion.

I am facing the same problem and would like to suggest adopting this pull request.
I want to connect an external clock source to the camera and would like to set xclk = - 1.

@me-no-dev
Allow me to offer an additional explanation of the part in question.

The ESP32 and ESP32S2 implementations generate clocks using LEDC by determining if xclk is positive.
In other words, when xclk = -1 is set, the system operates without setting LEDC.

esp32-camera/driver/esp_camera.c

Lines 154 to 157 in a6f13d9

	if (config->pin_xclk >= 0) {
	ESP_LOGD(TAG, "Enabling XCLK output");
	CAMERA_ENABLE_OUT_CLOCK(config);
	}

The ESP32S3 implementation crashes at runtime because it accesses the array without checking if xclk is positive.

esp32-camera/target/esp32s3/ll_cam.c

Lines 321 to 326 in a6f13d9

	PIN_FUNC_SELECT(GPIO_PIN_MUX_REG[config->pin_xclk], PIN_FUNC_GPIO);
	gpio_set_direction(config->pin_xclk, GPIO_MODE_OUTPUT);
	gpio_set_pull_mode(config->pin_xclk, GPIO_FLOATING);
	gpio_matrix_out(config->pin_xclk, CAM_CLK_IDX, false, false);

Therefore, it makes sense to add the xclk value check only to the ESP32S3 implementation, as in this pull request.

In other words, the current situation is that xclk = -1 causes a crash only on the ESP32S3.
By adopting this pull request, it would be possible to set xclk = -1 on all processors.

Please consider this matter.

[igrr]

@lovyan03 Thank you for the explanation, I think it makes sense to add this check.

[igrr]

@Kevincoooool Could you please address the minor formatting issue and rebase your PR on top of the latest master branch? Thank you.

[igrr]

Formatting nitpick: the opening brace should be on the same line as the if, and there should be a space between if and (.

[igrr]

Closing in favor of #438.

@Kevincoooool by the way, it is not necessary to create a new branch or a PR when you want to update an existing PR. You can push the changes to the same branch and the PR will be updated automatically. It is also okay to force-push to feature or bugfix branches like this one, in case you do perform a rebase of your local branch.