--- linux-4.9.37/drivers/mfd/goke_fmc.c	1970-01-01 03:00:00.000000000 +0300
+++ linux-4.9.y/drivers/mfd/goke_fmc.c	2021-06-07 13:01:33.000000000 +0300
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) Hunan Goke,Chengdu Goke,Shandong Goke. 2021. All rights reserved.
+ */
+
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/goke_fmc.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+unsigned char fmc_cs_user[FMC_MAX_CHIP_NUM];
+
+DEFINE_MUTEX(fmc_switch_mutex);
+EXPORT_SYMBOL_GPL(fmc_switch_mutex);
+
+/* ------------------------------------------------------------------------ */
+static const struct mfd_cell bsp_fmc_devs[] = {
+	{
+		.name = "bsp_spi_nor",
+		.of_compatible = "goke,fmc-spi-nor",
+	},
+	{
+		.name = "bsp_spi_nand",
+		.of_compatible = "goke,fmc-spi-nand",
+	},
+};
+
+static int bsp_fmc_probe(struct platform_device *pdev)
+{
+	struct bsp_fmc *fmc;
+	struct resource *res;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	fmc = devm_kzalloc(dev, sizeof(*fmc), GFP_KERNEL);
+	if (!fmc) {
+		return -ENOMEM;
+	}
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "control");
+	fmc->regbase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(fmc->regbase)) {
+		return PTR_ERR(fmc->regbase);
+	}
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "memory");
+	fmc->iobase = devm_ioremap_resource(dev, res);
+	if (IS_ERR(fmc->iobase)) {
+		return PTR_ERR(fmc->iobase);
+	}
+
+	fmc->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(fmc->clk)) {
+		return PTR_ERR(fmc->clk);
+	}
+
+	if (of_property_read_u32(dev->of_node, "max-dma-size", &fmc->dma_len)) {
+		dev_err(dev, "Please set the suitable max-dma-size value !!!\n");
+		return -ENOMEM;
+	}
+
+	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
+	if (ret) {
+		dev_warn(dev, "Unable to set dma mask\n");
+		return ret;
+	}
+
+	fmc->buffer = dmam_alloc_coherent(dev, fmc->dma_len,
+					  &fmc->dma_buffer, GFP_KERNEL);
+	if (IS_ERR(fmc->buffer)) {
+		return PTR_ERR(fmc->buffer);
+	}
+
+	mutex_init(&fmc->lock);
+
+	platform_set_drvdata(pdev, fmc);
+
+	ret = mfd_add_devices(dev, 0, bsp_fmc_devs,
+			      ARRAY_SIZE(bsp_fmc_devs), NULL, 0, NULL);
+	if (ret) {
+		dev_err(dev, "add mfd devices failed: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int bsp_fmc_remove(struct platform_device *pdev)
+{
+	struct bsp_fmc *fmc = platform_get_drvdata(pdev);
+
+	dmam_free_coherent(&pdev->dev, fmc->dma_len,
+			   fmc->buffer, fmc->dma_buffer);
+	mfd_remove_devices(&pdev->dev);
+	mutex_destroy(&fmc->lock);
+
+	return 0;
+}
+
+static const struct of_device_id bsp_fmc_of_match_tbl[] = {
+	{ .compatible = "goke,fmc"},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, bsp_fmc_of_match_tbl);
+
+static struct platform_driver bsp_fmc_driver = {
+	.driver = {
+		.name = "fmc",
+		.of_match_table = bsp_fmc_of_match_tbl,
+	},
+	.probe = bsp_fmc_probe,
+	.remove = bsp_fmc_remove,
+};
+module_platform_driver(bsp_fmc_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Goke Flash Memory Controller Driver");