Add an environment variable to disable or force picodvi

and auto-set height and support rotation similar to how it's done on some
of those dot clock display espressif boards

Author: jepler

docs/environment.rst

@@ -121,6 +121,8 @@ a rotation of 0. Attempting to initialize the screen with a rotation other than
 90, 180 or 270 is not supported and will result in an unexpected screen rotation.
 
 `Sunton ESP32-8048S050 <https://circuitpython.org/board/sunton_esp32_8048S050/>`_
+`Adafruit Feather RP2350 <https://circuitpython.org/board/adafruit_feather_rp2350/>`_
+`Adafruit Metro RP2350 <https://circuitpython.org/board/adafruit_metro_rp2350/>`_
 
 CIRCUITPY_DISPLAY_FREQUENCY
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -132,6 +134,20 @@ display frequency.
 
 `Sunton ESP32-8048S050 <https://circuitpython.org/board/sunton_esp32_8048S050/>`_
 
+
+CIRCUITPY_PICODVI_ENABLE
+~~~~~~~~~~~~~~~~~~~~~~~~
+Whether to configure the display at board initialization time, one of the following:
+
+.. code-block::
+
+    CIRCUITPY_PICODVI_ENABLE="detect" # when EDID EEPROM is detected (default)
+    CIRCUITPY_PICODVI_ENABLE="always"
+    CIRCUITPY_PICODVI_ENABLE="never"
+
+`Adafruit Feather RP2350 <https://circuitpython.org/board/adafruit_feather_rp2350/>`_
+`Adafruit Metro RP2350 <https://circuitpython.org/board/adafruit_metro_rp2350/>`_
+
 CIRCUITPY_DISPLAY_WIDTH, _HEIGHT, and _COLOR_DEPTH (RP2350 boards with DVI or HSTX connector)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Selects the desired resolution and color depth.
@@ -142,18 +158,14 @@ Supported resolutions are:
 
 The default value, if unspecified, is 320x240 with 16 bits per pixel.
 
-setting ``CIRCUITPY_DISPLAY_WIDTH = 0`` disables automatic display configuration. In this case, the other
-values are not used.
-
-If an EDID EEPROM is not detected on the I2C bus, automatic display
-configuration is not performed.
+If height is unspecified, it is set from the width. For example, a width of 640
+implies a height of 480.
 
-Example: Configure the display to 640x480 black and white (1bpp):
+Example: Configure the display to 640x480 black and white (1 bit per pixel):
 
 .. code-block::
 
     CIRCUITPY_DISPLAY_WIDTH=640
-    CIRCUITPY_DISPLAY_WIDTH=480
     CIRCUITPY_DISPLAY_COLOR_DEPTH=1
 
 `Adafruit Feather RP2350 <https://circuitpython.org/board/adafruit_feather_rp2350/>`_

ports/raspberrypi/common-hal/picodvi/__init__.c

@@ -16,37 +16,73 @@
 #include "py/runtime.h"
 #include "supervisor/port_heap.h"
 
-void picodvi_autoconstruct(void) {
-    #if defined(DEFAULT_DVI_BUS_CLK_DP)
-    if (get_safe_mode() != SAFE_MODE_NONE) {
-        return;
+#if defined(DEFAULT_DVI_BUS_CLK_DP)
+static bool picodvi_autoconstruct_enabled(void) {
+    char buf[sizeof("detect")];
+    buf[0] = 0;
+
+    // (any failure leaves the content of buf untouched: an empty nul-terminated string
+    (void)common_hal_os_getenv_str("CIRCUITPY_PICODVI_ENABLE", buf, sizeof(buf));
+
+    if (!strcasecmp(buf, "never")) {
+        return false;
+    }
+    if (!strcasecmp(buf, "always")) {
+        return true;
     }
-    // check if address 0x50 is live on the I2C bus -- return if not
+
+    // It's "detect" or else an invalid value which is treated the same as "detect".
+
+    // check if address 0x50 is live on the I2C bus
     busio_i2c_obj_t *i2c = common_hal_board_create_i2c(0);
     if (!i2c) {
-        return;
+        return false;
     }
     if (!common_hal_busio_i2c_try_lock(i2c)) {
-        return;
+        return false;
     }
     bool probed = common_hal_busio_i2c_probe(i2c, 0x50);
     common_hal_busio_i2c_unlock(i2c);
-    if (!probed) {
+    return probed;
+}
+
+// For picodvi_autoconstruct to work, the 8 DVI/HSTX pin names must be defined, AND
+// i2c bus 0 must also be connected to DVI with on-board pull ups
+void picodvi_autoconstruct(void) {
+    if (get_safe_mode() != SAFE_MODE_NONE) {
         return;
     }
 
+    if (!picodvi_autoconstruct_enabled()) {
+        return;
+    }
 
     mp_int_t width = 320;
-    mp_int_t height = 240;
+    mp_int_t height = 0;
     mp_int_t color_depth = 16;
+    mp_int_t rotation = 0;
 
     (void)common_hal_os_getenv_int("CIRCUITPY_DISPLAY_WIDTH", &width);
     (void)common_hal_os_getenv_int("CIRCUITPY_DISPLAY_HEIGHT", &height);
     (void)common_hal_os_getenv_int("CIRCUITPY_DISPLAY_COLOR_DEPTH", &color_depth);
+    (void)common_hal_os_getenv_int("CIRCUITPY_DISPLAY_ROTATION", &rotation);
 
-    if (width == 0) {
+    if (height == 0) {
+        switch (width) {
+            case 640:
+                height = 480;
+                break;
+            case 320:
+                height = 240;
+                break;
+        }
+    }
+
+    if (rotation != 0 && rotation != 90 && rotation != 180 && rotation != 270) {
+        // invalid rotation
         return;
     }
+
     if (!common_hal_picodvi_framebuffer_preflight(width, height, color_depth)) {
         // TODO: User configuration can fail without a self-explanatory message.
         // sadly, a print from here does NOT reach boot_out.txt, so no point in
@@ -75,7 +111,10 @@ void picodvi_autoconstruct(void) {
     common_hal_framebufferio_framebufferdisplay_construct(
         display,
         MP_OBJ_FROM_PTR(fb),
-        0,
+        rotation,
         true);
-    #endif
 }
+#else
+void picodvi_autoconstruct(void) {
+}
+#endif