add epd_powerdown for lilygo

README.md

@@ -86,7 +86,25 @@ The following list is compiled from past experiences and GitHub issues:
  * **The existing image fades / darkens when updating a partial screen region.** Make sure the VCOM voltage is [calibrated](https://epdiy.readthedocs.io/en/latest/getting_started.html#calibrate-vcom) for your specific display.
  * **The second third of the image is replaced with the last third.** This seems to be a timing issue we could not yet quite figure out the reason for. For a workarround or suggestions please [join the discussion](https://github.com/vroland/epdiy/issues/15).
  * **The ESP does not boot correctly when external periperals are connected.** Make sure not to pull GPIO12 high during boot, as it is a strapping pin internal voltage selection (https://github.com/vroland/epdiy/issues/17).
-
+
+LilyGo Boards
+---------------
+There are several differences with these boards.
+One particular one is the way the LilyGo handles power to the display the official lilygo code has two states.
+This is now handled in epdiy in a different way to the lilygo code.
+**epd_poweroff()** completely turns the power off to the display and the other peripherals of the lilygo.
+The new function **epd_powerdown()** keeps the peripherals on (this allows the touch functions to continue to work). 
+**epd_poweroff() should allways be called before sleeping the system**
+You can still use touch to wake the screen with the following.
+In Arduino it works like this.
+`epd_poweroff();`
+
+ `epd_deinit();`
+
+ `esp_sleep_enable_ext1_wakeup(GPIO_SEL_13, ESP_EXT1_WAKEUP_ANY_HIGH);`
+
+ `esp_deep_sleep_start();`
+
 More on E-Paper Displays
 ------------------------
 
@@ -115,4 +133,3 @@ The board and schematic are licensed under a <a rel="license" href="https://crea
 
 Firmware and remaining examples are licensed under the terms of the GNU Lesser GPL version 3.
 Utilities are licensed under the terms of the MIT license.
-

src/epd_driver/config_reg_v2.h

@@ -66,6 +66,28 @@ static void cfg_poweron(epd_config_register_t *cfg) {
   // END POWERON
 }
 
+#if defined(CONFIG_EPD_BOARD_REVISION_LILYGO_T5_47)
+static void cfg_powerdown(epd_config_register_t *cfg) {
+  // This was re-purposed as power enable however it also disables the touch.
+  // this workaround may still leave power on to epd and as such may cause other
+  // problems such as grey screen.
+  cfg->pos_power_enable = false;
+  push_cfg(cfg);
+  busy_delay(10 * 240);
+
+  cfg->neg_power_enable = false;
+  cfg->pos_power_enable = false;
+  push_cfg(cfg);
+  busy_delay(100 * 240);
+
+  cfg->ep_stv = false;
+  cfg->ep_output_enable = false;
+  cfg->ep_mode = false;
+  cfg->power_disable = true;
+  push_cfg(cfg);
+}
+#endif
+
 static void cfg_poweroff(epd_config_register_t *cfg) {
   // POWEROFF
   cfg->pos_power_enable = false;

src/epd_driver/display_ops.c

@@ -106,6 +106,13 @@ void epd_poweron() {
   cfg_poweron(&config_reg);
 }
 
+#if defined(CONFIG_EPD_BOARD_REVISION_LILYGO_T5_47)
+void epd_powerdown() {
+  cfg_powerdown(&config_reg);
+  i2s_gpio_detach();
+}
+#endif
+
 void epd_poweroff() {
   cfg_poweroff(&config_reg);
   i2s_gpio_detach();

src/epd_driver/include/epd_driver.h

@@ -206,6 +206,30 @@ void epd_deinit();
 /** Enable display power supply. */
 void epd_poweron();
 
+#if defined(CONFIG_EPD_BOARD_REVISION_LILYGO_T5_47)
+/** This is a Lilygo47 specific function
+
+  This is a  work around a hardware issue with the Lilygo47 epd_poweroff() turns off the epaper completely
+  however the hardware of the Lilygo47 is different than the official boards. Which means that on the Lilygo47 this
+  disables power to the touchscreen.
+
+  This is a workaround to allow to disable display power but not the touch screen.
+  On the Lilygo the epd power flag was re-purposed as power enable
+  for everything. This is a hardware thing. 
+ \warning This workaround may still leave power on to epd and as such may cause other problems such as grey screen.
+  Please also use epd_poweroff() and epd_deinit() when you sleep the system wake on touch will still work.
+
+ Arduino specific code:
+ \code{.c}
+  epd_poweroff();
+  epd_deinit();
+  esp_sleep_enable_ext1_wakeup(GPIO_SEL_13, ESP_EXT1_WAKEUP_ANY_HIGH);
+  esp_deep_sleep_start();
+  \endcode
+*/
+void epd_powerdown();
+#endif
+
 /** Disable display power supply. */
 void epd_poweroff();