452 lines
16 KiB
C
452 lines
16 KiB
C
/*#############################################################################
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## Author: Shaun Reed ##
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## Legal: All Content (c) 2025 Shaun Reed, all rights reserved ##
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## ##
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## Contact: shaunrd0@gmail.com | URL: www.shaunreed.com ##
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##############################################################################
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*/
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#ifndef PANEL_DEVICE_H
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#define PANEL_DEVICE_H
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#include <esp_lcd_panel_dev.h>
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#include <esp_lcd_panel_io.h>
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#include <esp_lcd_panel_ops.h>
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#include <esp_log.h>
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#include <esp_timer.h>
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#include <sys/unistd.h>
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#include <i2c.h>
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#include <pixel.h>
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static esp_timer_handle_t esp_timer_;
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#include <display/lv_display.h>
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/// Tag used for ESP logging.
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static const char* LCD_TAG = "LCD component";
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// LVGL library is not thread-safe, this example calls LVGL APIs from tasks.
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// We must use a mutex to protect it.
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static _lock_t lv_lock_;
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// LVGL reserves 2x4 bytes in the buffer to be used as a palette.
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// This additional space must be added to the IPanelDevice::buf_size_.
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#define LVGL_PALETTE_SIZE 8
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#define LVGL_TICK_PERIOD_MS 5
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#define LVGL_TASK_STACK_SIZE (4 * 1024)
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#define LVGL_TASK_PRIORITY 2
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#define LCD_H_RES 128
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#define LCD_V_RES 64
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// According to specific display hardware.
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// https://www.digikey.com/en/products/detail/winstar-display/WEA012864DWPP3N00003/20533255
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#define SCREEN_WIDTH 128 // OLED display width, in pixels.
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#define SCREEN_HEIGHT 64 // OLED display height, in pixels.
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// According to SSD1306 datasheet.
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// https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf
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#define I2C_HW_ADDR 0x3C
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#define LCD_PIXEL_CLOCK_HZ (400 * 1000)
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// Bit number used to represent command and parameter
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#define LCD_CMD_BITS 8
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#define LCD_PARAM_BITS 8
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/**
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* Retrieve the device specific vendor configuration structure.
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*
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* @return Address of vendor configuration structure.
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*/
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typedef void* (*vendor_config_cb_t)();
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/**
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* Registers LVGL ticker timer callback for rendering this display.
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*
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* An implementation of the interface can optionally override this method to
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* provide custom LVGL callbacks and tick configurations.
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*/
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typedef void (*register_lvgl_tick_timer_cb_t)();
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/**
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* Initializes the ESP panel using vendor specific APIs and configurations.
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* This method should implement any setup logic specific to the device.
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*
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* @param config ESP LCD panel configuration.
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* @param io ESP LCD panel IO handle.
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* @param [out] panel ESP LCD panel handle output pointer location.
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*/
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typedef void (*init_panel_cb_t)(esp_lcd_panel_dev_config_t* config,
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esp_lcd_panel_io_handle_t io,
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esp_lcd_panel_handle_t* panel);
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/**
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* Registers LVGL draw buffers and callbacks for this display.
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*
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* An implementation of the interface can optionally override this method to
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* provide custom LVGL callbacks and display configurations.
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*
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* @param display_handle LVGL display handle to use for rendering.
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* @param io_handle IO handle for the ESP LCD panel.
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*/
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typedef void (*register_rendering_data_cb_t)(
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lv_display_t* display_handle, esp_lcd_panel_io_handle_t io_handle, void*,
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size_t);
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/**
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* Encapsulates vendor specific ESP LCD panel initialization logic.
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* This pure virtual interface can be inherited from for using new LCD devices.
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* See SSD1306 as an example to implement IPanelDevice for NT35510 or ST7789.
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*
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* At this time only I2C is supported.
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* Classes that inherit from this interface should likely be marked final.
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*/
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struct IPanelDevice
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{
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/// Width of the device screen in pixels.
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int32_t width_;
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/// Height of the device screen in pixels.
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int32_t height_;
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/// RST GPIO pin number.
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int rst_num_;
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/// LVGL draw buffer size for the device.
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size_t lv_buf_size_;
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/// ESP LCD panel IO configuration.
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esp_lcd_panel_io_i2c_config_t esp_io_config_;
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/// LVGL draw buffer associated with this Display's lv_display_t.
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void* lv_buf_;
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/// Callback used to initialize the ESP panel.
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init_panel_cb_t init_panel_cb;
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/// Callback used to register LVGL tick timer.
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register_lvgl_tick_timer_cb_t register_lvgl_tick_timer_cb;
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/// Callback used to register LVGL draw buffers.
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register_rendering_data_cb_t register_rendering_data_cb;
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/// Callback used to fetch the display vendor configuration.
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vendor_config_cb_t vendor_config_cb;
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};
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/**
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* Static accessor to a static buffer to store draw buffer data for the panel.
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*
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* This method is protected to allow an implementation to provide a custom
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* callback method similar to IPanelDevice::lvgl_flush_cb.
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*
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* The buffer is allocated statically within the scope of this function to
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* allow creating multiple panels that _each_ manage their own statically
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* allocated draw buffer data. This simplifies implementing the interface by
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* taking this responsibility off of the implementor. The buffer will only be
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* allocated if this method is called, so the memory is only used if required.
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*
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* @return Pointer to uint8 draw buffer data.
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* @sa register_rendering_data for overriding LVGL rendering callbacks.
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*/
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static uint8_t* get_additional_draw_buffer()
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{
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// Static to the scope of this function, not the compilation unit.
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// For LV_COLOR_FORMAT_I1 we need an extra buffer to hold converted data.
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static uint8_t oled_buffer[LCD_H_RES * LCD_V_RES / 8];
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return oled_buffer;
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}
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/**
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* The callback invoked when panel IO finishes transferring color data.
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* This signals that the panel is ready to flush image data to the display.
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*
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* @param panel LCD panel IO handles.
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* @param data Panel IO event data, fed by driver.
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* @param user_ctx User data, passed from `esp_lcd_panel_io_xxx_config_t`.
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* @return Whether a high priority task has been waken up by this function.
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* @sa register_rendering_data for overriding this callback.
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*/
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static bool lvgl_flush_ready_cb(esp_lcd_panel_io_handle_t,
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esp_lcd_panel_io_event_data_t*,
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void* user_ctx)
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{
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lv_display_t* disp = (lv_display_t*)user_ctx;
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lv_display_flush_ready(disp);
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return false;
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}
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/**
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* The callback invoked for flushing the rendered image to the display.
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*
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* `px_map` contains the rendered image as raw pixel map and it should be
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* copied to `area` on the display.
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*
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* The following details are crucial for understanding the logic surrounding
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* flushing to the display in this example.
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*
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* The order of bits within the px_map from _LVGL_ is MSB first.
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* MSB LSB
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* bits 7 6 5 4 3 2 1 0
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* pixels 0 1 2 3 4 5 6 7
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* Left Right
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*
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* The bytes from _LVGL_ are mapped to pixel rows of the display
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* 8 bits (pixels) per byte -
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* [0, 0, 0, 0, 0, 0, 0, 0]
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* [0, 0, 0, 0, 0, 0, 0, 0]
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* [0, 0, 0, 0, 0, 0, 0, 0]
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*
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* The order of bits expected by the _display driver_ is LSB first.
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* We must preserve pairing of each bit and pixel when writing to the display.
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* LSB MSB
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* bits 0 1 2 3 4 5 6 7
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* pixels 7 6 5 4 3 2 1 0
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* Left Right
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*
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* Bytes expected by the _display driver_ map to pixel columns of the display.
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* 8 bits (pixels) per byte -
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* [0, [0, [0, [0,
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* 0, 0, 0, 0,
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* 0, 0, 0, 0,
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* 0, 0, 0, 0,
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* 0, 0, 0, 0,
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* 0, 0, 0, 0,
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* 0, 0, 0, 0,
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* 0] 0] 0] 0]
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*
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* These layouts in memory have no opinion on the shape of the image. The
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* beginning and end of a row or a column for example is entirely dependent
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* on how the data is accessed. The vertical and horitzontal resolution may
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* vary between displays.
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*
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* For the LV_COLOR_FORMAT_I1 color format we are using, an additional buffer
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* is needed for transposing the bits to the vertical arrangement required by
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* the display driver that is outlined above.
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*
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* This callback implementation is an example of handling this transposition
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* and flushing the data to the display in the expected format.
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*
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* @param display LVGL display handle to use for rendering.
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* @param area Area of the display being flushed.
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* @param px_map Rendered image data for writing to the display area.
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* @sa register_rendering_data for overriding this callback.
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* @sa get_additional_draw_buffer
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*/
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static void lvgl_flush_cb(lv_display_t* display, const lv_area_t* area,
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uint8_t* px_map)
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{
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esp_lcd_panel_handle_t panel_handle =
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(esp_lcd_panel_handle_t)lv_display_get_user_data(display);
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// Necessary because LVGL reserves 2x4 bytes in the buffer for a palette.
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// Since we are monochrome, we don't need these additional bytes.
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// For more information about the monochrome, please refer to:
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// https://docs.lvgl.io/9.2/porting/display.html#monochrome-displays
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// Skip the palette here.
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px_map += LVGL_PALETTE_SIZE;
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uint16_t hor_res = lv_display_get_physical_horizontal_resolution(display);
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int32_t x1 = area->x1;
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int32_t x2 = area->x2;
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int32_t y1 = area->y1;
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int32_t y2 = area->y2;
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// As of 03/01/2025 master branch of LVGL contains this helper for the same.
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// https://docs.lvgl.io/master/API/draw/sw/lv_draw_sw_utils.html
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// lv_draw_sw_i1_convert_to_vtiled()
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for (int32_t y = y1; y <= y2; y++)
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{
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for (int32_t x = x1; x <= x2; x++)
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{
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// Get the byte offset of the pixel coordinates using
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// horizontal-mapping.
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int h_offset = horizontal_byte_offset_long(x, y, hor_res);
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// True if the pixel is lit, else false.
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bool chroma_color = px_map[h_offset] & msb_mask(x);
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// We need an additional buffer for transposing the pixel data to
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// the vertical format required by the display driver.
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uint8_t* buf = get_additional_draw_buffer();
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// Move to the position in the auxillary buffer where the pixel is
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// stored.
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buf += vertical_byte_offset_long(x, y, hor_res);
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// Write the single bit to the monochrome display mapped vertically.
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// Take the Least Significant Bit mask of the Y coordinate to select
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// the bit representing a pixel at position y in a vertically-mapped
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// display.
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if (chroma_color)
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{
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// Set the vertically-mapped pixel to on.
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*buf &= ~lsb_mask(y);
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}
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else
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{
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// Set the vertically-mapped pixel to off.
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*buf |= lsb_mask(y);
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}
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}
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}
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// Pass the draw buffer to the driver.
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ESP_ERROR_CHECK(esp_lcd_panel_draw_bitmap(
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panel_handle, x1, y1, x2 + 1, y2 + 1, get_additional_draw_buffer()));
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}
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/**
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* Callback invoked for every period of the timer.
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*
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* This callback _must_ call lv_tick_inc to inform LVGL how much time has
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* elapsed since the last period of the timer.
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*
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* @param data User data passed to the callback.
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* @sa register_lvgl_tick_timer for setting user data and the tick period of
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* the timer, or overriding this callback entirely.
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*/
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static void lvgl_increase_tick_cb(void*)
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{
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// Tell LVGL how many milliseconds has elapsed
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lv_tick_inc(LVGL_TICK_PERIOD_MS);
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}
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/**
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* FreeRTOS task callback invoked for handling LVGL events or updating the UI.
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*
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* This function is intentionally an endless loop and should never return.
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* LVGL initialization logic can optionally be added before entering the loop.
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* Input logic can optionally be handled within the loop.
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*
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* This callback _must_ call lv_timer_handler to handle LVGL periodic timers.
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*
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* @param data User data passed to the callback.
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* @sa register_lvgl_tick_timer for overriding this callback.
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*/
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[[noreturn]] static void lvgl_port_task(void*)
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{
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// Optionally initialize some LVGL objects here before entering loop below.
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ESP_LOGI(LCD_TAG, "Starting LVGL task");
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for (uint32_t time_to_next_ms = 0; true; usleep(1000 * time_to_next_ms))
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{
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// Obtain LVGL API lock before calling any LVGL methods.
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_lock_acquire(&lv_lock_);
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// Optionally handle LVGL input or event logic here.
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// Update LVGL periodic timers.
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time_to_next_ms = lv_timer_handler();
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_lock_release(&lv_lock_);
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}
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}
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/**
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* Registers LVGL ticker timer callback for rendering this display.
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*
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* An implementation of the interface can optionally override this method to
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* provide custom LVGL callbacks and tick configurations.
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*/
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static void register_lvgl_tick_timer()
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{
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ESP_LOGI(LCD_TAG, "Use esp_timer to increase LVGL tick");
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const esp_timer_create_args_t esp_timer_args = {
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.callback = &lvgl_increase_tick_cb,
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// Data to pass to the lvgl_port_task callback.
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.arg = NULL,
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.name = "lvgl_tick",
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};
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/// Start periodic ESP timer handle.
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ESP_LOGI(LCD_TAG, "Creating esp_timer with name: '%s'",
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esp_timer_args.name);
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ESP_ERROR_CHECK(esp_timer_create(&esp_timer_args, &esp_timer_));
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ESP_ERROR_CHECK(
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esp_timer_start_periodic(esp_timer_, LVGL_TICK_PERIOD_MS * 1000));
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ESP_LOGI(LCD_TAG, "Starting esp_timer with name: '%s'",
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esp_timer_args.name);
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// LVGL requires a FreeRTOS task for running it's event loop.
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// The lvgl_port_task callback can update the UI or handle input logic.
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// For this basic example we don't do either of these things.
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ESP_LOGI(LCD_TAG, "Create LVGL FreeRTOS task");
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// Optionally set user data to pass to LVGL's FreeRTOS task callback here.
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void* user_data = NULL;
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xTaskCreate(lvgl_port_task, "LVGL", LVGL_TASK_STACK_SIZE, user_data,
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LVGL_TASK_PRIORITY, NULL);
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}
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static void register_rendering_data(lv_display_t* display_handle,
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esp_lcd_panel_io_handle_t io_handle,
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void* lv_buf, size_t lv_buf_size)
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{
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// Create draw buffer.
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ESP_LOGI(LCD_TAG, "Allocate separate LVGL draw buffers");
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lv_buf =
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heap_caps_calloc(1, lv_buf_size, MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
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assert(lv_buf);
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ESP_LOGI(LCD_TAG, "Set LVGL draw buffers");
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// Color format must be set first, LVGL9 support new monochromatic format.
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lv_display_set_color_format(display_handle, LV_COLOR_FORMAT_I1);
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lv_display_set_buffers(display_handle, lv_buf, NULL, lv_buf_size,
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LV_DISPLAY_RENDER_MODE_FULL);
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lv_display_set_rotation(display_handle, LV_DISPLAY_ROTATION_0);
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ESP_LOGI(LCD_TAG, "Set LVGL callback for flushing to the display");
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lv_display_set_flush_cb(display_handle, lvgl_flush_cb);
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ESP_LOGI(LCD_TAG,
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"Register io panel callback for LVGL flush ready notification");
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const esp_lcd_panel_io_callbacks_t cbs = {
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.on_color_trans_done = lvgl_flush_ready_cb,
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};
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ESP_ERROR_CHECK(esp_lcd_panel_io_register_event_callbacks(io_handle, &cbs,
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display_handle));
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}
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/// Callback used to fail, indicating the device is not fully initialized.
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static void* fail_vendor_config_cb()
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{
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ESP_LOGE(LCD_TAG, "Callback is unset: IPanelDevice::vendor_config_cb");
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assert(false);
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}
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/// Callback used to fail, indicating the device is not fully initialized.
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static void fail_init_panel_cb(esp_lcd_panel_dev_config_t*,
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esp_lcd_panel_io_handle_t,
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esp_lcd_panel_handle_t*)
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{
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ESP_LOGE(LCD_TAG, "Callback is unset: IPanelDevice::init_panel_cb");
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assert(false);
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}
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static struct IPanelDevice LCD_new_panel()
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{
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return (struct IPanelDevice){
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.width_ = LCD_H_RES,
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.height_ = LCD_V_RES,
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.rst_num_ = I2C_DEFAULT_PIN_RST,
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.lv_buf_size_ = LCD_H_RES * LCD_V_RES / 8 + LVGL_PALETTE_SIZE,
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.esp_io_config_ =
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(esp_lcd_panel_io_i2c_config_t){
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.dev_addr = I2C_HW_ADDR,
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// User data to pass to the LVGL flush_ready callback.
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// See IPanelDevice::lvgl_flush_ready_cb
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.user_ctx = NULL,
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.control_phase_bytes = 1,
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.dc_bit_offset = 6,
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.lcd_cmd_bits = LCD_CMD_BITS,
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.lcd_param_bits = LCD_PARAM_BITS,
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.scl_speed_hz = LCD_PIXEL_CLOCK_HZ,
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},
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.init_panel_cb = fail_init_panel_cb, // Must be assigned by caller
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.register_lvgl_tick_timer_cb = register_lvgl_tick_timer,
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.register_rendering_data_cb = register_rendering_data,
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.vendor_config_cb = fail_vendor_config_cb, // Must be assigned by caller
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};
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}
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#endif // PANEL_DEVICE_H
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