--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Host interface (LPC or eSPI) configuration on Nuvoton BMC
+ * Copyright (c) 2022 Nuvoton Technology Corp.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <asm/io.h>
+#include <dm/device_compat.h>
+#include <linux/bitfield.h>
+
+#define SMC_CTL_REG_ADDR 0xc0001001
+#define SMC_CTL_HOSTWAIT 0x80
+
+/* GCR Register Offsets */
+#define HIFCR 0x50
+#define MFSEL1 0x260
+#define MFSEL4 0x26c
+
+/* ESPI Register offsets */
+#define ESPICFG 0x4
+#define ESPIHINDP 0x80
+
+/* MFSEL bit fileds */
+#define MFSEL1_LPCSEL BIT(26)
+#define MFSEL4_ESPISEL BIT(8)
+
+/* ESPICFG bit fileds */
+#define CHSUPP_MASK GENMASK(27, 24)
+#define IOMODE_MASK GENMASK(9, 8)
+#define IOMODE_SDQ FIELD_PREP(IOMODE_MASK, 3)
+#define MAXFREQ_MASK GENMASK(12, 10)
+#define MAXFREQ_33MHZ FIELD_PREP(MAXFREQ_MASK, 2)
+
+/* ESPIHINDP bit fileds */
+#define AUTO_SBLD BIT(4)
+#define AUTO_HS1 BIT(8)
+#define AUTO_HS2 BIT(12)
+#define AUTO_HS3 BIT(16)
+
+static int npcm_host_intf_bind(struct udevice *dev)
+{
+ struct regmap *syscon;
+ void __iomem *base;
+ u32 ch_supp, val;
+ u32 ioaddr;
+ const char *type;
+ int ret;
+
+ /* Release host wait */
+ setbits_8(SMC_CTL_REG_ADDR, SMC_CTL_HOSTWAIT);
+
+ syscon = syscon_regmap_lookup_by_phandle(dev, "syscon");
+ if (IS_ERR(syscon)) {
+ dev_err(dev, "%s: unable to get syscon, dev %s\n", __func__, dev->name);
+ return PTR_ERR(syscon);
+ }
+
+ ioaddr = dev_read_u32_default(dev, "ioaddr", 0);
+ if (ioaddr)
+ regmap_write(syscon, HIFCR, ioaddr);
+
+ type = dev_read_string(dev, "type");
+ if (!type)
+ return -EINVAL;
+
+ if (!strcmp(type, "espi")) {
+ base = dev_read_addr_ptr(dev);
+ if (!base)
+ return -EINVAL;
+
+ ret = dev_read_u32(dev, "channel-support", &ch_supp);
+ if (ret)
+ return ret;
+
+ /* Select eSPI pins function */
+ regmap_update_bits(syscon, MFSEL1, MFSEL1_LPCSEL, 0);
+ regmap_update_bits(syscon, MFSEL4, MFSEL4_ESPISEL, MFSEL4_ESPISEL);
+
+ val = AUTO_SBLD | AUTO_HS1 | AUTO_HS2 | AUTO_HS3 | ch_supp;
+ writel(val, base + ESPIHINDP);
+
+ val = readl(base + ESPICFG);
+ val &= ~(CHSUPP_MASK | IOMODE_MASK | MAXFREQ_MASK);
+ val |= IOMODE_SDQ | MAXFREQ_33MHZ | FIELD_PREP(CHSUPP_MASK, ch_supp);
+ writel(val, base + ESPICFG);
+ } else if (!strcmp(type, "lpc")) {
+ /* Select LPC pin function */
+ regmap_update_bits(syscon, MFSEL4, MFSEL4_ESPISEL, 0);
+ regmap_update_bits(syscon, MFSEL1, MFSEL1_LPCSEL, MFSEL1_LPCSEL);
+ }
+
+ return 0;
+}
+
+static const struct udevice_id npcm_hostintf_ids[] = {
+ { .compatible = "nuvoton,npcm750-host-intf" },
+ { .compatible = "nuvoton,npcm845-host-intf" },
+ { }
+};
+
+U_BOOT_DRIVER(npcm_host_intf) = {
+ .name = "npcm_host_intf",
+ .id = UCLASS_MISC,
+ .of_match = npcm_hostintf_ids,
+ .bind = npcm_host_intf_bind,
+};