--- /dev/null
+From a8374683868634012ac873d628fa581fcc452e9c Mon Sep 17 00:00:00 2001
+From: Aleksei Sviridkin <f@lex.la>
+Date: Tue, 16 Jun 2026 16:28:44 +0300
+Subject: mtd: spinand: add support for HeYangTek HYF1GQ4UDACAE
+
+The HeYangTek HYF1GQ4UDACAE is a 1 Gbit (128 MiB) SLC SPI-NAND with
+2048 + 64 byte pages and on-die 4-bit / 512-byte ECC; its JEDEC
+manufacturer ID is 0xc9. The die is GD5F1GQ4-compatible, so the OOB
+layout is taken from the in-tree gd5fxgq4xa. The die exposes only a
+coarse 2-bit ECC status with no fine-grained bitflip-count register, so
+the status is decoded into a representative number of corrected bitflips.
+
+It is found, among others, on some Keenetic KN-3411 (Buddy 6) units.
+
+Datasheet:
+https://www.heyangtek.cn/previewfile.jsp?file=ABUIABA9GAAgwsvRnwYo-eDpsgc
+
+Signed-off-by: Aleksei Sviridkin <f@lex.la>
+Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
+---
+ drivers/mtd/nand/spi/Makefile | 2 +-
+ drivers/mtd/nand/spi/core.c | 1 +
+ drivers/mtd/nand/spi/heyangtek.c | 132 +++++++++++++++++++++++++++++++++++++++
+ include/linux/mtd/spinand.h | 1 +
+ 4 files changed, 135 insertions(+), 1 deletion(-)
+ create mode 100644 drivers/mtd/nand/spi/heyangtek.c
+
+--- a/drivers/mtd/nand/spi/Makefile
++++ b/drivers/mtd/nand/spi/Makefile
+@@ -1,5 +1,5 @@
+ # SPDX-License-Identifier: GPL-2.0
+ spinand-objs := core.o otp.o
+-spinand-objs += alliancememory.o ato.o esmt.o fmsh.o foresee.o gigadevice.o macronix.o
++spinand-objs += alliancememory.o ato.o esmt.o fmsh.o foresee.o gigadevice.o heyangtek.o macronix.o
+ spinand-objs += micron.o paragon.o skyhigh.o toshiba.o winbond.o xtx.o
+ obj-$(CONFIG_MTD_SPI_NAND) += spinand.o
+--- a/drivers/mtd/nand/spi/core.c
++++ b/drivers/mtd/nand/spi/core.c
+@@ -1231,6 +1231,7 @@ static const struct spinand_manufacturer
+ &fmsh_spinand_manufacturer,
+ &foresee_spinand_manufacturer,
+ &gigadevice_spinand_manufacturer,
++ &heyangtek_spinand_manufacturer,
+ ¯onix_spinand_manufacturer,
+ µn_spinand_manufacturer,
+ ¶gon_spinand_manufacturer,
+--- /dev/null
++++ b/drivers/mtd/nand/spi/heyangtek.c
+@@ -0,0 +1,132 @@
++// SPDX-License-Identifier: GPL-2.0
++/*
++ * Authors:
++ * Andrey Zolotarev <andrey.zolotarev@keenetic.com> - the main driver logic
++ * Aleksei Sviridkin <f@lex.la> - adaptation to the mainline Linux kernel
++ *
++ * Based on:
++ * https://github.com/keenetic/kernel-49/commit/bacade569fb12bc0ad31ba09bca9b890118fbca7
++ */
++
++#include <linux/device.h>
++#include <linux/kernel.h>
++#include <linux/mtd/spinand.h>
++
++#define SPINAND_MFR_HEYANGTEK 0xc9
++
++#define HYF1GQ4_STATUS_ECC_LIMIT_BITFLIPS (3 << 4)
++
++static SPINAND_OP_VARIANTS(read_cache_variants,
++ SPINAND_PAGE_READ_FROM_CACHE_1S_4S_4S_OP(0, 1, NULL, 0, 0),
++ SPINAND_PAGE_READ_FROM_CACHE_1S_1S_4S_OP(0, 1, NULL, 0, 0),
++ SPINAND_PAGE_READ_FROM_CACHE_1S_2S_2S_OP(0, 1, NULL, 0, 0),
++ SPINAND_PAGE_READ_FROM_CACHE_1S_1S_2S_OP(0, 1, NULL, 0, 0),
++ SPINAND_PAGE_READ_FROM_CACHE_FAST_1S_1S_1S_OP(0, 1, NULL, 0, 0),
++ SPINAND_PAGE_READ_FROM_CACHE_1S_1S_1S_OP(0, 1, NULL, 0, 0));
++
++static SPINAND_OP_VARIANTS(write_cache_variants,
++ SPINAND_PROG_LOAD_1S_1S_4S_OP(true, 0, NULL, 0),
++ SPINAND_PROG_LOAD_1S_1S_1S_OP(true, 0, NULL, 0));
++
++static SPINAND_OP_VARIANTS(update_cache_variants,
++ SPINAND_PROG_LOAD_1S_1S_4S_OP(false, 0, NULL, 0),
++ SPINAND_PROG_LOAD_1S_1S_1S_OP(false, 0, NULL, 0));
++
++/*
++ * HYF1GQ4UDACAE is a GD5F1GQ4-compatible die, so the OOB layout is taken
++ * from gd5fxgq4xa: the on-die ECC parity occupies bytes 8..15 of each
++ * 16-byte section, the bad block marker sits in byte 0 and the remaining
++ * bytes are exposed as free.
++ */
++static int hyf1gq4_ooblayout_ecc(struct mtd_info *mtd, int section,
++ struct mtd_oob_region *region)
++{
++ if (section > 3)
++ return -ERANGE;
++
++ region->offset = (16 * section) + 8;
++ region->length = 8;
++
++ return 0;
++}
++
++static int hyf1gq4_ooblayout_free(struct mtd_info *mtd, int section,
++ struct mtd_oob_region *region)
++{
++ if (section > 3)
++ return -ERANGE;
++
++ if (section) {
++ region->offset = 16 * section;
++ region->length = 8;
++ } else {
++ /* section 0 has one byte reserved for the bad block marker */
++ region->offset = 1;
++ region->length = 7;
++ }
++
++ return 0;
++}
++
++static const struct mtd_ooblayout_ops hyf1gq4_ooblayout = {
++ .ecc = hyf1gq4_ooblayout_ecc,
++ .free = hyf1gq4_ooblayout_free,
++};
++
++static int hyf1gq4_ecc_get_status(struct spinand_device *spinand, u8 status)
++{
++ struct nand_device *nand = spinand_to_nand(spinand);
++
++ switch (status & STATUS_ECC_MASK) {
++ case STATUS_ECC_NO_BITFLIPS:
++ return 0;
++
++ case STATUS_ECC_UNCOR_ERROR:
++ return -EBADMSG;
++
++ case STATUS_ECC_HAS_BITFLIPS:
++ /*
++ * The die exposes only a coarse 2-bit ECC status and has no
++ * register for the exact bitflip count. This code means
++ * "corrected, below the refresh threshold", so report half of
++ * the ECC strength as a representative value.
++ */
++ return nanddev_get_ecc_conf(nand)->strength / 2;
++
++ case HYF1GQ4_STATUS_ECC_LIMIT_BITFLIPS:
++ /*
++ * "Corrected, refresh recommended": report the full ECC
++ * strength so the upper layers relocate the data.
++ */
++ return nanddev_get_ecc_conf(nand)->strength;
++
++ default:
++ break;
++ }
++
++ return -EINVAL;
++}
++
++static const struct spinand_info heyangtek_spinand_table[] = {
++ SPINAND_INFO("HYF1GQ4UDACAE",
++ SPINAND_ID(SPINAND_READID_METHOD_OPCODE_ADDR, 0x21),
++ NAND_MEMORG(1, 2048, 64, 64, 1024, 20, 1, 1, 1),
++ NAND_ECCREQ(4, 512),
++ SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
++ &write_cache_variants,
++ &update_cache_variants),
++ SPINAND_HAS_QE_BIT,
++ SPINAND_ECCINFO(&hyf1gq4_ooblayout,
++ hyf1gq4_ecc_get_status)),
++};
++
++static const struct spinand_manufacturer_ops heyangtek_spinand_manuf_ops = {
++};
++
++const struct spinand_manufacturer heyangtek_spinand_manufacturer = {
++ .id = SPINAND_MFR_HEYANGTEK,
++ .name = "HeYangTek",
++ .chips = heyangtek_spinand_table,
++ .nchips = ARRAY_SIZE(heyangtek_spinand_table),
++ .ops = &heyangtek_spinand_manuf_ops,
++};
+--- a/include/linux/mtd/spinand.h
++++ b/include/linux/mtd/spinand.h
+@@ -365,6 +365,7 @@ extern const struct spinand_manufacturer
+ extern const struct spinand_manufacturer fmsh_spinand_manufacturer;
+ extern const struct spinand_manufacturer foresee_spinand_manufacturer;
+ extern const struct spinand_manufacturer gigadevice_spinand_manufacturer;
++extern const struct spinand_manufacturer heyangtek_spinand_manufacturer;
+ extern const struct spinand_manufacturer macronix_spinand_manufacturer;
+ extern const struct spinand_manufacturer micron_spinand_manufacturer;
+ extern const struct spinand_manufacturer paragon_spinand_manufacturer;