spi_flash: support working on differnt buses and frequency

components/spi_flash/spi_flash_chip_drivers.c

@@ -0,0 +1,38 @@
+// Copyright 2015-2019 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <stdlib.h>
+#include "spi_flash_chip_driver.h"
+#include "spi_flash_chip_generic.h"
+#include "spi_flash_chip_issi.h"
+#include "sdkconfig.h"
+
+/*
+ * Default registered chip drivers. Note these are tested in order and first
+ * match is taken, so generic/catchall entries should go last. Note that the
+ * esp_flash_registered_flash_ops pointer can be changed to point to a different
+ * array of registered ops, if desired.
+ *
+ * It can be configured to support only available chips in the sdkconfig, to
+ * avoid possible issues, and speed up the auto-detecting.
+ */
+static const spi_flash_chip_t *default_registered_chips[] = {
+#ifdef CONFIG_SPI_FLASH_SUPPORT_ISSI_CHIP
+    &esp_flash_chip_issi,
+#endif
+    &esp_flash_chip_generic,
+    NULL,
+};
+
+const spi_flash_chip_t **esp_flash_registered_chips = default_registered_chips;