spi: added an API to get max transaction length and use in spi lcd driver

components/driver/spi/gpspi/spi_master.c

@@ -111,6 +111,7 @@ We have two bits to control the interrupt:
 */
 
 #include <string.h>
+#include <sys/param.h>
 #include "esp_private/spi_common_internal.h"
 #include "driver/spi_master.h"
 #include "esp_clk_tree.h"
@@ -126,7 +127,6 @@ We have two bits to control the interrupt:
 #include "hal/spi_ll.h"
 #include "esp_heap_caps.h"
 
-
 typedef struct spi_device_t spi_device_t;
 
 /// struct to hold private transaction data (like tx and rx buffer for DMA).
@@ -1111,3 +1111,20 @@ esp_err_t SPI_MASTER_ISR_ATTR spi_device_polling_transmit(spi_device_handle_t ha
 
     return spi_device_polling_end(handle, portMAX_DELAY);
 }
+
+esp_err_t spi_bus_get_max_transaction_len(spi_host_device_t host_id, size_t *max_bytes)
+{
+    SPI_CHECK(is_valid_host(host_id), "invalid host", ESP_ERR_INVALID_ARG);
+    if (bus_driver_ctx[host_id] == NULL || max_bytes == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+
+    spi_host_t *host = bus_driver_ctx[host_id];
+    if (host->bus_attr->dma_enabled) {
+        *max_bytes = MIN(host->bus_attr->max_transfer_sz, (SPI_LL_DMA_MAX_BIT_LEN / 8));
+    } else {
+        *max_bytes = MIN(host->bus_attr->max_transfer_sz, (SPI_LL_CPU_MAX_BIT_LEN / 8));
+    }
+
+    return ESP_OK;
+}

components/driver/spi/include/driver/spi_master.h

@@ -391,6 +391,18 @@ void spi_get_timing(bool gpio_is_used, int input_delay_ns, int eff_clk, int *dum
   */
 int spi_get_freq_limit(bool gpio_is_used, int input_delay_ns);
 
+/**
+ * @brief Get max length (in bytes) of one transaction
+ *
+ * @param       host_id    SPI peripheral
+ * @param[out]  max_bytes  Max length of one transaction, in bytes
+ *
+ * @return
+ *        - ESP_OK:               On success
+ *        - ESP_ERR_INVALID_ARG:  Invalid argument
+ */
+esp_err_t spi_bus_get_max_transaction_len(spi_host_device_t host_id, size_t *max_bytes);
+
 #ifdef __cplusplus
 }
 #endif

components/esp_lcd/src/esp_lcd_panel_io_spi.c

@@ -21,7 +21,6 @@
 #include "esp_log.h"
 #include "esp_check.h"
 #include "esp_lcd_common.h"
-#include "esp_private/spi_common_internal.h"
 
 static const char *TAG = "lcd_panel.io.spi";
 
@@ -107,9 +106,13 @@ esp_err_t esp_lcd_new_panel_io_spi(esp_lcd_spi_bus_handle_t bus, const esp_lcd_p
     spi_panel_io->base.tx_color = panel_io_spi_tx_color;
     spi_panel_io->base.del = panel_io_spi_del;
     spi_panel_io->base.register_event_callbacks = panel_io_spi_register_event_callbacks;
-    spi_panel_io->spi_trans_max_bytes = spi_bus_get_attr((spi_host_device_t)bus)->max_transfer_sz;
+
+    size_t max_trans_bytes = 0;
+    ESP_GOTO_ON_ERROR(spi_bus_get_max_transaction_len((spi_host_device_t)bus, &max_trans_bytes), err, TAG, "get spi max transaction len failed");
+    spi_panel_io->spi_trans_max_bytes = max_trans_bytes;
+
     *ret_io = &(spi_panel_io->base);
-    ESP_LOGD(TAG, "new spi lcd panel io @%p", spi_panel_io);
+    ESP_LOGD(TAG, "new spi lcd panel io @%p, max_trans_bytes: %d", spi_panel_io, (int)max_trans_bytes);
 
     return ESP_OK;