esp_lcd: Add RX into SPI lcd panel.

components/esp_lcd/include/esp_lcd_panel_io.h

@@ -47,7 +47,7 @@ esp_err_t esp_lcd_panel_io_rx_param(esp_lcd_panel_io_handle_t io, int lcd_cmd, v
  *       this function will wait until they are finished and the queue is empty before sending the command(s).
  *
  * @param[in] io LCD panel IO handle, which is created by other factory API like `esp_lcd_new_panel_io_spi()`
- * @param[in] lcd_cmd The specific LCD command
+ * @param[in] lcd_cmd The specific LCD command (set to -1 if no command needed - only in SPI and I2C)
  * @param[in] param Buffer that holds the command specific parameters, set to NULL if no parameter is needed for the command
  * @param[in] param_size Size of `param` in memory, in bytes, set to zero if no parameter is needed for the command
  * @return

components/esp_lcd/src/esp_lcd_panel_io_spi.c

@@ -22,6 +22,7 @@
 
 static const char *TAG = "lcd_panel.io.spi";
 
+static esp_err_t panel_io_spi_rx_param(esp_lcd_panel_io_t *io, int lcd_cmd, void *param, size_t param_size);
 static esp_err_t panel_io_spi_tx_param(esp_lcd_panel_io_t *io, int lcd_cmd, const void *param, size_t param_size);
 static esp_err_t panel_io_spi_tx_color(esp_lcd_panel_io_t *io, int lcd_cmd, const void *color, size_t color_size);
 static esp_err_t panel_io_spi_del(esp_lcd_panel_io_t *io);
@@ -65,7 +66,6 @@ esp_err_t esp_lcd_new_panel_io_spi(esp_lcd_spi_bus_handle_t bus, const esp_lcd_p
     ESP_GOTO_ON_FALSE(spi_panel_io, ESP_ERR_NO_MEM, err, TAG, "no mem for spi panel io");
 
     spi_device_interface_config_t devcfg = {
-        // currently the driver only supports TX path, so half duplex is enough
         .flags = SPI_DEVICE_HALFDUPLEX | (io_config->flags.lsb_first ? SPI_DEVICE_TXBIT_LSBFIRST : 0),
         .clock_speed_hz = io_config->pclk_hz,
         .mode = io_config->spi_mode,
@@ -96,6 +96,7 @@ esp_err_t esp_lcd_new_panel_io_spi(esp_lcd_spi_bus_handle_t bus, const esp_lcd_p
     spi_panel_io->lcd_param_bits = io_config->lcd_param_bits;
     spi_panel_io->dc_gpio_num = io_config->dc_gpio_num;
     spi_panel_io->queue_size = io_config->trans_queue_depth;
+    spi_panel_io->base.rx_param = panel_io_spi_rx_param;
     spi_panel_io->base.tx_param = panel_io_spi_tx_param;
     spi_panel_io->base.tx_color = panel_io_spi_tx_color;
     spi_panel_io->base.del = panel_io_spi_del;
@@ -170,36 +171,45 @@ static esp_err_t panel_io_spi_tx_param(esp_lcd_panel_io_t *io, int lcd_cmd, cons
     spi_transaction_t *spi_trans = NULL;
     lcd_spi_trans_descriptor_t *lcd_trans = NULL;
     esp_lcd_panel_io_spi_t *spi_panel_io = __containerof(io, esp_lcd_panel_io_spi_t, base);
+    bool send_cmd = (lcd_cmd >= 0);
+
+    spi_device_acquire_bus(spi_panel_io->spi_dev, portMAX_DELAY);
 
     // before issue a polling transaction, need to wait queued transactions finished
-    for (size_t i = 0; i < spi_panel_io->num_trans_inflight; i++) {
+    size_t num_trans_inflight = spi_panel_io->num_trans_inflight;
+    for (size_t i = 0; i < num_trans_inflight; i++) {
         ret = spi_device_get_trans_result(spi_panel_io->spi_dev, &spi_trans, portMAX_DELAY);
         ESP_GOTO_ON_ERROR(ret, err, TAG, "recycle spi transactions failed");
+        spi_panel_io->num_trans_inflight--;
     }
-    spi_panel_io->num_trans_inflight = 0;
     lcd_trans = &spi_panel_io->trans_pool[0];
     memset(lcd_trans, 0, sizeof(lcd_spi_trans_descriptor_t));
     spi_lcd_prepare_cmd_buffer(spi_panel_io, &lcd_cmd);
     lcd_trans->base.user = spi_panel_io;
-    lcd_trans->flags.dc_gpio_level = !spi_panel_io->flags.dc_data_level; // set D/C line to command mode
+    lcd_trans->base.flags |= SPI_TRANS_CS_KEEP_ACTIVE;
-    lcd_trans->base.length = spi_panel_io->lcd_cmd_bits;
-    lcd_trans->base.tx_buffer = &lcd_cmd;
     if (spi_panel_io->flags.octal_mode) {
         // use 8 lines for transmitting command, address and data
         lcd_trans->base.flags |= (SPI_TRANS_MULTILINE_CMD | SPI_TRANS_MULTILINE_ADDR | SPI_TRANS_MODE_OCT);
     }
-    if (spi_panel_io->flags.dc_as_cmd_phase) { // encoding DC value to SPI command phase when necessary
+
-        lcd_trans->base.cmd = !spi_panel_io->flags.dc_data_level;
+    if (send_cmd) {
+        lcd_trans->flags.dc_gpio_level = !spi_panel_io->flags.dc_data_level; // set D/C line to command mode
+        if (spi_panel_io->flags.dc_as_cmd_phase) { // encoding DC value to SPI command phase when necessary
+            lcd_trans->base.cmd = !spi_panel_io->flags.dc_data_level;
+        }
+        lcd_trans->base.length = spi_panel_io->lcd_cmd_bits;
+        lcd_trans->base.tx_buffer = &lcd_cmd;
+        // command is short, using polling mode
+        ret = spi_device_polling_transmit(spi_panel_io->spi_dev, &lcd_trans->base);
+        ESP_GOTO_ON_ERROR(ret, err, TAG, "spi transmit (polling) command failed");
     }
-    // command is short, using polling mode
-    ret = spi_device_polling_transmit(spi_panel_io->spi_dev, &lcd_trans->base);
-    ESP_GOTO_ON_ERROR(ret, err, TAG, "spi transmit (polling) command failed");
 
     if (param && param_size) {
         spi_lcd_prepare_param_buffer(spi_panel_io, param, param_size);
         lcd_trans->flags.dc_gpio_level = spi_panel_io->flags.dc_data_level; // set D/C line to data mode
         lcd_trans->base.length = param_size * 8; // transaction length is in bits
         lcd_trans->base.tx_buffer = param;
+        lcd_trans->base.flags &= ~SPI_TRANS_CS_KEEP_ACTIVE;
         if (spi_panel_io->flags.dc_as_cmd_phase) { // encoding DC value to SPI command phase when necessary
             lcd_trans->base.cmd = spi_panel_io->flags.dc_data_level;
         }
@@ -209,6 +219,68 @@ static esp_err_t panel_io_spi_tx_param(esp_lcd_panel_io_t *io, int lcd_cmd, cons
     }
 
 err:
+    spi_device_release_bus(spi_panel_io->spi_dev);
+
+    return ret;
+}
+
+static esp_err_t panel_io_spi_rx_param(esp_lcd_panel_io_t *io, int lcd_cmd, void *param, size_t param_size)
+{
+    esp_err_t ret = ESP_OK;
+    spi_transaction_t *spi_trans = NULL;
+    lcd_spi_trans_descriptor_t *lcd_trans = NULL;
+    esp_lcd_panel_io_spi_t *spi_panel_io = __containerof(io, esp_lcd_panel_io_spi_t, base);
+    bool send_cmd = (lcd_cmd >= 0);
+
+    spi_device_acquire_bus(spi_panel_io->spi_dev, portMAX_DELAY);
+
+    // before issue a polling transaction, need to wait queued transactions finished
+    size_t num_trans_inflight = spi_panel_io->num_trans_inflight;
+    for (size_t i = 0; i < num_trans_inflight; i++) {
+        ret = spi_device_get_trans_result(spi_panel_io->spi_dev, &spi_trans, portMAX_DELAY);
+        ESP_GOTO_ON_ERROR(ret, err, TAG, "recycle spi transactions failed");
+        spi_panel_io->num_trans_inflight--;
+    }
+    lcd_trans = &spi_panel_io->trans_pool[0];
+    memset(lcd_trans, 0, sizeof(lcd_spi_trans_descriptor_t));
+    spi_lcd_prepare_cmd_buffer(spi_panel_io, &lcd_cmd);
+    lcd_trans->base.user = spi_panel_io;
+    lcd_trans->base.flags |= SPI_TRANS_CS_KEEP_ACTIVE;
+    if (spi_panel_io->flags.octal_mode) {
+        // use 8 lines for transmitting command, address and data
+        lcd_trans->base.flags |= (SPI_TRANS_MULTILINE_CMD | SPI_TRANS_MULTILINE_ADDR | SPI_TRANS_MODE_OCT);
+    }
+
+    if (send_cmd) {
+        lcd_trans->flags.dc_gpio_level = !spi_panel_io->flags.dc_data_level; // set D/C line to command mode
+        if (spi_panel_io->flags.dc_as_cmd_phase) { // encoding DC value to SPI command phase when necessary
+            lcd_trans->base.cmd = !spi_panel_io->flags.dc_data_level;
+        }
+        lcd_trans->base.length = spi_panel_io->lcd_cmd_bits;
+        lcd_trans->base.tx_buffer = &lcd_cmd;
+        // command is short, using polling mode
+        ret = spi_device_polling_transmit(spi_panel_io->spi_dev, &lcd_trans->base);
+        ESP_GOTO_ON_ERROR(ret, err, TAG, "spi transmit (polling) command failed");
+    }
+
+    if (param && param_size) {
+        lcd_trans->flags.dc_gpio_level = spi_panel_io->flags.dc_data_level; // set D/C line to data mode
+        lcd_trans->base.length = 0;
+        lcd_trans->base.tx_buffer = NULL;
+        lcd_trans->base.rxlength = param_size * 8; // Read length in bits
+        lcd_trans->base.rx_buffer = param;
+        lcd_trans->base.flags &= ~SPI_TRANS_CS_KEEP_ACTIVE;
+        if (spi_panel_io->flags.dc_as_cmd_phase) { // encoding DC value to SPI command phase when necessary
+            lcd_trans->base.cmd = spi_panel_io->flags.dc_data_level;
+        }
+        // parameter is usually short, using polling mode
+        ret = spi_device_polling_transmit(spi_panel_io->spi_dev, &lcd_trans->base);
+        ESP_GOTO_ON_ERROR(ret, err, TAG, "spi transmit (polling) param failed");
+    }
+
+err:
+    spi_device_release_bus(spi_panel_io->spi_dev);
+
     return ret;
 }