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authorChristopher Hill <ch6574@gmail.com>2020-05-25 21:05:00 -0400
committerAdrian Schmutzler <freifunk@adrianschmutzler.de>2020-06-15 21:16:18 +0200
commitfa70b3a4bbc65d372d735004d9df894bd1c89c81 (patch)
treea56a9e308de8c1a657cbd4df1d5cd834b167203a /target/linux/ath79/files
parent344e75eb2b5653ed350121b4a7beb292049c24c0 (diff)
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ath79: add Mikrotik rb4xx series drivers
This adds 3 Mikrotik rb4xx series drivers as follows: rb4xx-cpld: This is in the mfd subsystem, and is the parent CPLD device that interfaces between the SoC SPI bus and its two children below. rb4xx-gpio: This is the GPIO expander. rb4xx-nand: This is the NAND driver. The history of this code comes in three phases. 1. The first is a May 2015 attempt to push the equivalient ar71xx rb4xx drivers upstream. See https://lore.kernel.org/patchwork/patch/940880/. Module-author: Gabor Juhos <juhosg@openwrt.org> Module-author: Imre Kaloz <kaloz@openwrt.org> Module-author: Bert Vermeulen <bert@biot.com> 2. Next several ar71xx patches were applied bringing the code current. commit 7bbf4117c6fe4b764d9d7c62fb2bcf6dd93bff2c Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de> commit af79fdbe4af32a287798b579141204bda056b8aa commit 889272d92db689fd9c910243635e44c9d8323095 commit e21cb649a235180563363b8af5ba8296b9ac0baa commit 7c09fa4a7492ca436f2c94bd9a465b7c5bbeed6f Signed-off-by: Felix Fietkau <nbd@nbd.name> 3. Finally a heavy refactor to split the driver into the three new subsystems, and updated to work with the device tree configuration, plus updates and review feedback incorporated Reviewed-by: Thibaut VARĂˆNE <hacks@slashdirt.org> Signed-off-by: Christopher Hill <ch6574@gmail.com>
Diffstat (limited to 'target/linux/ath79/files')
-rw-r--r--target/linux/ath79/files/drivers/gpio/gpio-rb4xx.c172
-rw-r--r--target/linux/ath79/files/drivers/mfd/rb4xx-cpld.c182
-rw-r--r--target/linux/ath79/files/drivers/mtd/nand/raw/nand_rb4xx.c297
-rw-r--r--target/linux/ath79/files/include/mfd/rb4xx-cpld.h25
4 files changed, 676 insertions, 0 deletions
diff --git a/target/linux/ath79/files/drivers/gpio/gpio-rb4xx.c b/target/linux/ath79/files/drivers/gpio/gpio-rb4xx.c
new file mode 100644
index 0000000000..f8022436e0
--- /dev/null
+++ b/target/linux/ath79/files/drivers/gpio/gpio-rb4xx.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * GPIO driver for the MikroTik RouterBoard 4xx series
+ *
+ * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ * Copyright (C) 2015 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2020 Christopher Hill <ch6574@gmail.com>
+ *
+ * This file was based on the driver for Linux 2.6.22 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+ *
+ * N.B. driver probe reports "DMA mask not set" warnings which are
+ * an artifact of using a platform_driver as an MFD device child.
+ * See conversation here https://lkml.org/lkml/2020/4/28/675
+ */
+#include <linux/platform_device.h>
+#include <linux/gpio/driver.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+#include <mfd/rb4xx-cpld.h>
+
+struct rb4xx_gpio {
+ struct rb4xx_cpld *cpld;
+ struct device *dev;
+
+ struct gpio_chip chip;
+ struct mutex lock;
+ u16 values; /* bitfield of GPIO 0-8 current values */
+};
+
+static int rb4xx_gpio_cpld_set(struct rb4xx_gpio *gpio, unsigned int offset,
+ int value)
+{
+ struct rb4xx_cpld *cpld = gpio->cpld;
+ u16 values;
+ int ret;
+
+ mutex_lock(&gpio->lock);
+ values = gpio->values;
+
+ if (value)
+ values |= BIT(offset);
+ else
+ values &= ~(BIT(offset));
+
+ if (values == gpio->values) {
+ ret = 0;
+ goto unlock;
+ }
+
+ if (offset < 8) {
+ ret = cpld->gpio_set_0_7(cpld, values & 0xff);
+ } else if (offset == 8) {
+ ret = cpld->gpio_set_8(cpld, values >> 8);
+ }
+
+ if(likely(!ret))
+ gpio->values = values;
+
+unlock:
+ mutex_unlock(&gpio->lock);
+ return ret;
+}
+
+static int rb4xx_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+ return 0; /* All 9 GPIOs are out */
+}
+
+static int rb4xx_gpio_direction_input(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ return -EOPNOTSUPP;
+}
+
+static int rb4xx_gpio_direction_output(struct gpio_chip *chip,
+ unsigned int offset, int value)
+{
+ return rb4xx_gpio_cpld_set(gpiochip_get_data(chip), offset, value);
+}
+
+static int rb4xx_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ struct rb4xx_gpio *gpio = gpiochip_get_data(chip);
+ int ret;
+
+ mutex_lock(&gpio->lock);
+ ret = (gpio->values >> offset) & 0x1;
+ mutex_unlock(&gpio->lock);
+
+ return ret;
+}
+
+static void rb4xx_gpio_set(struct gpio_chip *chip, unsigned int offset,
+ int value)
+{
+ rb4xx_gpio_cpld_set(gpiochip_get_data(chip), offset, value);
+}
+
+static int rb4xx_gpio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device *parent = dev->parent;
+ struct rb4xx_gpio *gpio;
+ u32 val;
+
+ if (!parent)
+ return -ENODEV;
+
+ gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
+ if (!gpio)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, gpio);
+ gpio->cpld = dev_get_drvdata(parent);
+ gpio->dev = dev;
+ gpio->values = 0;
+ mutex_init(&gpio->lock);
+
+ gpio->chip.label = "rb4xx-gpio";
+ gpio->chip.parent = dev;
+ gpio->chip.owner = THIS_MODULE;
+ gpio->chip.get_direction = rb4xx_gpio_get_direction;
+ gpio->chip.direction_input = rb4xx_gpio_direction_input;
+ gpio->chip.direction_output = rb4xx_gpio_direction_output;
+ gpio->chip.get = rb4xx_gpio_get;
+ gpio->chip.set = rb4xx_gpio_set;
+ gpio->chip.ngpio = 9;
+ gpio->chip.base = -1;
+ gpio->chip.can_sleep = 1;
+
+ if (!of_property_read_u32(dev->of_node, "base", &val))
+ gpio->chip.base = val;
+
+ return gpiochip_add_data(&gpio->chip, gpio);
+}
+
+static int rb4xx_gpio_remove(struct platform_device *pdev)
+{
+ struct rb4xx_gpio *gpio = platform_get_drvdata(pdev);
+
+ gpiochip_remove(&gpio->chip);
+ mutex_destroy(&gpio->lock);
+
+ return 0;
+}
+
+static const struct platform_device_id rb4xx_gpio_id_table[] = {
+ { "mikrotik,rb4xx-gpio", },
+ { },
+};
+MODULE_DEVICE_TABLE(platform, rb4xx_gpio_id_table);
+
+static struct platform_driver rb4xx_gpio_driver = {
+ .probe = rb4xx_gpio_probe,
+ .remove = rb4xx_gpio_remove,
+ .id_table = rb4xx_gpio_id_table,
+ .driver = {
+ .name = "rb4xx-gpio",
+ },
+};
+
+module_platform_driver(rb4xx_gpio_driver);
+
+MODULE_DESCRIPTION("Mikrotik RB4xx GPIO driver");
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org>");
+MODULE_AUTHOR("Bert Vermeulen <bert@biot.com>");
+MODULE_AUTHOR("Christopher Hill <ch6574@gmail.com");
+MODULE_LICENSE("GPL v2");
diff --git a/target/linux/ath79/files/drivers/mfd/rb4xx-cpld.c b/target/linux/ath79/files/drivers/mfd/rb4xx-cpld.c
new file mode 100644
index 0000000000..da18424c63
--- /dev/null
+++ b/target/linux/ath79/files/drivers/mfd/rb4xx-cpld.c
@@ -0,0 +1,182 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * CPLD driver for the MikroTik RouterBoard 4xx series
+ *
+ * This driver provides access to a CPLD that interfaces between the SoC SPI bus
+ * and other devices. Behind the CPLD there is a NAND flash chip and five LEDs.
+ *
+ * The CPLD supports SPI two-wire mode, in which two bits are transferred per
+ * SPI clock cycle. The second bit is transmitted with the SoC's CS2 pin.
+ *
+ * The CPLD also acts as a GPIO expander.
+ *
+ * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ * Copyright (C) 2015 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2020 Christopher Hill <ch6574@gmail.com>
+ *
+ * This file was based on the driver for Linux 2.6.22 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+*/
+#include <linux/mfd/core.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+
+#include <mfd/rb4xx-cpld.h>
+
+/* CPLD commands */
+#define CPLD_CMD_WRITE_NAND 0x08 /* send cmd, n x send data, send idle */
+#define CPLD_CMD_WRITE_CFG 0x09 /* send cmd, n x send cfg */
+#define CPLD_CMD_READ_NAND 0x0a /* send cmd, send idle, n x read data */
+#define CPLD_CMD_READ_FAST 0x0b /* send cmd, 4 x idle, n x read data */
+#define CPLD_CMD_GPIO8_HIGH 0x0c /* send cmd */
+#define CPLD_CMD_GPIO8_LOW 0x0d /* send cmd */
+
+static int rb4xx_cpld_write_nand(struct rb4xx_cpld *cpld, const void *tx_buf,
+ unsigned int len)
+{
+ struct spi_message m;
+ static const u8 cmd = CPLD_CMD_WRITE_NAND;
+ struct spi_transfer t[3] = {
+ {
+ .tx_buf = &cmd,
+ .len = sizeof(cmd),
+ }, {
+ .tx_buf = tx_buf,
+ .len = len,
+ .tx_nbits = SPI_NBITS_DUAL,
+ }, {
+ .len = 1,
+ .tx_nbits = SPI_NBITS_DUAL,
+ },
+ };
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t[0], &m);
+ spi_message_add_tail(&t[1], &m);
+ spi_message_add_tail(&t[2], &m);
+ return spi_sync(cpld->spi, &m);
+}
+
+static int rb4xx_cpld_read_nand(struct rb4xx_cpld *cpld, void *rx_buf,
+ unsigned int len)
+{
+ struct spi_message m;
+ static const u8 cmd[2] = {
+ CPLD_CMD_READ_NAND, 0
+ };
+ struct spi_transfer t[2] = {
+ {
+ .tx_buf = &cmd,
+ .len = sizeof(cmd),
+ }, {
+ .rx_buf = rx_buf,
+ .len = len,
+ },
+ };
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t[0], &m);
+ spi_message_add_tail(&t[1], &m);
+ return spi_sync(cpld->spi, &m);
+}
+
+static int rb4xx_cpld_cmd(struct rb4xx_cpld *cpld, const void *tx_buf,
+ unsigned int len)
+{
+ struct spi_message m;
+ struct spi_transfer t = {
+ .tx_buf = tx_buf,
+ .len = len,
+ };
+
+ spi_message_init(&m);
+ spi_message_add_tail(&t, &m);
+ return spi_sync(cpld->spi, &m);
+}
+
+static int rb4xx_cpld_gpio_set_0_7(struct rb4xx_cpld *cpld, u8 values)
+{
+ /* GPIO 0-7 change can be sent via command + bitfield */
+ u8 cmd[2] = {
+ CPLD_CMD_WRITE_CFG, values
+ };
+ return rb4xx_cpld_cmd(cpld, &cmd, 2);
+}
+
+static int rb4xx_cpld_gpio_set_8(struct rb4xx_cpld *cpld, u8 value)
+{
+ /* GPIO 8 uses dedicated high/low commands */
+ u8 cmd = CPLD_CMD_GPIO8_HIGH | !!(value);
+ return rb4xx_cpld_cmd(cpld, &cmd, 1);
+}
+
+static const struct mfd_cell rb4xx_cpld_cells[] = {
+ {
+ .name = "mikrotik,rb4xx-gpio",
+ .of_compatible = "mikrotik,rb4xx-gpio",
+ }, {
+ .name = "mikrotik,rb4xx-nand",
+ .of_compatible = "mikrotik,rb4xx-nand",
+ },
+};
+
+static int rb4xx_cpld_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+ struct rb4xx_cpld *cpld;
+ int ret;
+
+ cpld = devm_kzalloc(dev, sizeof(*cpld), GFP_KERNEL);
+ if (!cpld)
+ return -ENOMEM;
+
+ dev_set_drvdata(dev, cpld);
+
+ cpld->spi = spi;
+ cpld->write_nand = rb4xx_cpld_write_nand;
+ cpld->read_nand = rb4xx_cpld_read_nand;
+ cpld->gpio_set_0_7 = rb4xx_cpld_gpio_set_0_7;
+ cpld->gpio_set_8 = rb4xx_cpld_gpio_set_8;
+
+ spi->mode = SPI_MODE_0 | SPI_TX_DUAL;
+ ret = spi_setup(spi);
+ if (ret)
+ return ret;
+
+ return devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+ rb4xx_cpld_cells,
+ ARRAY_SIZE(rb4xx_cpld_cells),
+ NULL, 0, NULL);
+}
+
+static int rb4xx_cpld_remove(struct spi_device *spi)
+{
+ return 0;
+}
+
+static const struct of_device_id rb4xx_cpld_dt_match[] = {
+ { .compatible = "mikrotik,rb4xx-cpld", },
+ { },
+};
+MODULE_DEVICE_TABLE(of, rb4xx_cpld_dt_match);
+
+static struct spi_driver rb4xx_cpld_driver = {
+ .probe = rb4xx_cpld_probe,
+ .remove = rb4xx_cpld_remove,
+ .driver = {
+ .name = "rb4xx-cpld",
+ .bus = &spi_bus_type,
+ .of_match_table = of_match_ptr(rb4xx_cpld_dt_match),
+ },
+};
+
+module_spi_driver(rb4xx_cpld_driver);
+
+MODULE_DESCRIPTION("Mikrotik RB4xx CPLD driver");
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org>");
+MODULE_AUTHOR("Bert Vermeulen <bert@biot.com>");
+MODULE_AUTHOR("Christopher Hill <ch6574@gmail.com");
+MODULE_LICENSE("GPL v2");
diff --git a/target/linux/ath79/files/drivers/mtd/nand/raw/nand_rb4xx.c b/target/linux/ath79/files/drivers/mtd/nand/raw/nand_rb4xx.c
new file mode 100644
index 0000000000..922d7095cb
--- /dev/null
+++ b/target/linux/ath79/files/drivers/mtd/nand/raw/nand_rb4xx.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * NAND driver for the MikroTik RouterBoard 4xx series
+ *
+ * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ * Copyright (C) 2015 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2020 Christopher Hill <ch6574@gmail.com>
+ *
+ * This file was based on the driver for Linux 2.6.22 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+ *
+ * N.B. driver probe reports "DMA mask not set" warnings which are
+ * an artifact of using a platform_driver as an MFD device child.
+ * See conversation here https://lkml.org/lkml/2020/4/28/675
+ */
+#include <linux/platform_device.h>
+#include <linux/mtd/rawnand.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/version.h>
+
+#include <mfd/rb4xx-cpld.h>
+
+struct rb4xx_nand {
+ struct rb4xx_cpld *cpld;
+ struct device *dev;
+
+ struct nand_chip chip;
+ struct gpio_desc *ale;
+ struct gpio_desc *cle;
+ struct gpio_desc *nce;
+ struct gpio_desc *rdy;
+};
+
+static int rb4xx_ooblayout_ecc(struct mtd_info *mtd, int section,
+ struct mtd_oob_region *oobregion)
+{
+ switch (section) {
+ case 0:
+ oobregion->offset = 8;
+ oobregion->length = 3;
+ return 0;
+ case 1:
+ oobregion->offset = 13;
+ oobregion->length = 3;
+ return 0;
+ default:
+ return -ERANGE;
+ }
+}
+
+static int rb4xx_ooblayout_free(struct mtd_info *mtd, int section,
+ struct mtd_oob_region *oobregion)
+{
+ switch (section) {
+ case 0:
+ oobregion->offset = 0;
+ oobregion->length = 4;
+ return 0;
+ case 1:
+ oobregion->offset = 4;
+ oobregion->length = 1;
+ return 0;
+ case 2:
+ oobregion->offset = 6;
+ oobregion->length = 2;
+ return 0;
+ case 3:
+ oobregion->offset = 11;
+ oobregion->length = 2;
+ return 0;
+ default:
+ return -ERANGE;
+ }
+}
+
+static const struct mtd_ooblayout_ops rb4xx_nand_ecclayout_ops = {
+ .ecc = rb4xx_ooblayout_ecc,
+ .free = rb4xx_ooblayout_free,
+};
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,20,0)
+static uint8_t rb4xx_nand_read_byte(struct mtd_info *mtd)
+{
+ struct rb4xx_nand *nand = mtd->priv;
+#else
+static u8 rb4xx_nand_read_byte(struct nand_chip *chip)
+{
+ struct rb4xx_nand *nand = chip->priv;
+#endif
+ struct rb4xx_cpld *cpld = nand->cpld;
+ u8 data;
+ int ret;
+
+ ret = cpld->read_nand(cpld, &data, 1);
+ if (unlikely(ret))
+ return 0xff;
+
+ return data;
+}
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,20,0)
+static void rb4xx_nand_write_buf(struct mtd_info *mtd, const uint8_t *buf,
+ int len)
+{
+ struct rb4xx_nand *nand = mtd->priv;
+#else
+static void rb4xx_nand_write_buf(struct nand_chip *chip, const u8 *buf, int len)
+{
+ struct rb4xx_nand *nand = chip->priv;
+#endif
+ struct rb4xx_cpld *cpld = nand->cpld;
+
+ cpld->write_nand(cpld, buf, len);
+}
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,20,0)
+static void rb4xx_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+ struct rb4xx_nand *nand = mtd->priv;
+#else
+static void rb4xx_nand_read_buf(struct nand_chip *chip, u8 *buf, int len)
+{
+ struct rb4xx_nand *nand = chip->priv;
+#endif
+ struct rb4xx_cpld *cpld = nand->cpld;
+
+ cpld->read_nand(cpld, buf, len);
+}
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,20,0)
+static void rb4xx_nand_cmd_ctrl(struct mtd_info *mtd, int dat, unsigned int ctrl)
+{
+ struct rb4xx_nand *nand = mtd->priv;
+#else
+static void rb4xx_nand_cmd_ctrl(struct nand_chip *chip, int dat,
+ unsigned int ctrl)
+{
+ struct rb4xx_nand *nand = chip->priv;
+#endif
+ struct rb4xx_cpld *cpld = nand->cpld;
+ u8 data = dat;
+
+ if (ctrl & NAND_CTRL_CHANGE) {
+ gpiod_set_value_cansleep(nand->cle, !!(ctrl & NAND_CLE));
+ gpiod_set_value_cansleep(nand->ale, !!(ctrl & NAND_ALE));
+ gpiod_set_value_cansleep(nand->nce, !(ctrl & NAND_NCE));
+ }
+
+ if (dat != NAND_CMD_NONE)
+ cpld->write_nand(cpld, &data, 1);
+}
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,20,0)
+static int rb4xx_nand_dev_ready(struct mtd_info *mtd)
+{
+ struct rb4xx_nand *nand = mtd->priv;
+#else
+static int rb4xx_nand_dev_ready(struct nand_chip *chip)
+{
+ struct rb4xx_nand *nand = chip->priv;
+#endif
+
+ return gpiod_get_value_cansleep(nand->rdy);
+}
+
+static int rb4xx_nand_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device *parent = dev->parent;
+ struct rb4xx_nand *nand;
+ struct mtd_info *mtd;
+ int ret;
+
+ if (!parent)
+ return -ENODEV;
+
+ nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
+ if (!nand)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, nand);
+ nand->cpld = dev_get_drvdata(parent);
+ nand->dev = dev;
+
+ nand->ale = devm_gpiod_get_index(dev, NULL, 0, GPIOD_OUT_LOW);
+ if (IS_ERR(nand->ale))
+ dev_err(dev, "missing gpio ALE: %ld\n", PTR_ERR(nand->ale));
+
+ nand->cle = devm_gpiod_get_index(dev, NULL, 1, GPIOD_OUT_LOW);
+ if (IS_ERR(nand->cle))
+ dev_err(dev, "missing gpio CLE: %ld\n", PTR_ERR(nand->cle));
+
+ nand->nce = devm_gpiod_get_index(dev, NULL, 2, GPIOD_OUT_LOW);
+ if (IS_ERR(nand->nce))
+ dev_err(dev, "missing gpio nCE: %ld\n", PTR_ERR(nand->nce));
+
+ nand->rdy = devm_gpiod_get_index(dev, NULL, 3, GPIOD_IN);
+ if (IS_ERR(nand->rdy))
+ dev_err(dev, "missing gpio RDY: %ld\n", PTR_ERR(nand->rdy));
+
+ if (IS_ERR(nand->ale) || IS_ERR(nand->cle) ||
+ IS_ERR(nand->nce) || IS_ERR(nand->rdy))
+ return -ENOENT;
+
+ gpiod_set_consumer_name(nand->ale, "mikrotik:nand:ALE");
+ gpiod_set_consumer_name(nand->cle, "mikrotik:nand:CLE");
+ gpiod_set_consumer_name(nand->nce, "mikrotik:nand:nCE");
+ gpiod_set_consumer_name(nand->rdy, "mikrotik:nand:RDY");
+
+ mtd = nand_to_mtd(&nand->chip);
+ mtd->priv = nand;
+ mtd->owner = THIS_MODULE;
+ mtd->dev.parent = dev;
+ mtd_set_of_node(mtd, dev->of_node);
+
+ if (mtd->writesize == 512)
+ mtd_set_ooblayout(mtd, &rb4xx_nand_ecclayout_ops);
+
+ nand->chip.ecc.mode = NAND_ECC_SOFT;
+ nand->chip.ecc.algo = NAND_ECC_HAMMING;
+ nand->chip.options = NAND_NO_SUBPAGE_WRITE;
+ nand->chip.priv = nand;
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,20,0)
+ nand->chip.read_byte = rb4xx_nand_read_byte;
+ nand->chip.write_buf = rb4xx_nand_write_buf;
+ nand->chip.read_buf = rb4xx_nand_read_buf;
+ nand->chip.cmd_ctrl = rb4xx_nand_cmd_ctrl;
+ nand->chip.dev_ready = rb4xx_nand_dev_ready;
+ nand->chip.chip_delay = 25;
+
+ ret = nand_scan(mtd, 1);
+#else
+ nand->chip.legacy.read_byte = rb4xx_nand_read_byte;
+ nand->chip.legacy.write_buf = rb4xx_nand_write_buf;
+ nand->chip.legacy.read_buf = rb4xx_nand_read_buf;
+ nand->chip.legacy.cmd_ctrl = rb4xx_nand_cmd_ctrl;
+ nand->chip.legacy.dev_ready = rb4xx_nand_dev_ready;
+ nand->chip.legacy.chip_delay = 25;
+
+ ret = nand_scan(&nand->chip, 1);
+#endif
+ if (ret)
+ return -ENXIO;
+
+ ret = mtd_device_register(mtd, NULL, 0);
+ if (ret) {
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,20,0)
+ nand_release(mtd);
+#else
+ nand_release(&nand->chip);
+#endif
+ return ret;
+ }
+
+ return 0;
+}
+
+static int rb4xx_nand_remove(struct platform_device *pdev)
+{
+ struct rb4xx_nand *nand = platform_get_drvdata(pdev);
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4,20,0)
+ nand_release(nand_to_mtd(&nand->chip));
+#else
+ nand_release(&nand->chip);
+#endif
+
+ return 0;
+}
+
+static const struct platform_device_id rb4xx_nand_id_table[] = {
+ { "mikrotik,rb4xx-nand", },
+ { },
+};
+MODULE_DEVICE_TABLE(platform, rb4xx_nand_id_table);
+
+static struct platform_driver rb4xx_nand_driver = {
+ .probe = rb4xx_nand_probe,
+ .remove = rb4xx_nand_remove,
+ .id_table = rb4xx_nand_id_table,
+ .driver = {
+ .name = "rb4xx-nand",
+ },
+};
+
+module_platform_driver(rb4xx_nand_driver);
+
+MODULE_DESCRIPTION("Mikrotik RB4xx NAND driver");
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org>");
+MODULE_AUTHOR("Bert Vermeulen <bert@biot.com>");
+MODULE_AUTHOR("Christopher Hill <ch6574@gmail.com");
+MODULE_LICENSE("GPL v2");
diff --git a/target/linux/ath79/files/include/mfd/rb4xx-cpld.h b/target/linux/ath79/files/include/mfd/rb4xx-cpld.h
new file mode 100644
index 0000000000..d73617bfb1
--- /dev/null
+++ b/target/linux/ath79/files/include/mfd/rb4xx-cpld.h
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * CPLD driver for the MikroTik RouterBoard 4xx series
+ *
+ * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ * Copyright (C) 2015 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2020 Christopher Hill <ch6574@gmail.com>
+ *
+ * This file was based on the driver for Linux 2.6.22 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+ */
+#include <linux/spi/spi.h>
+
+struct rb4xx_cpld {
+ struct spi_device *spi;
+
+ int (*write_nand)(struct rb4xx_cpld *self, const void *tx_buf,
+ unsigned int len);
+ int (*read_nand)(struct rb4xx_cpld *self, void *rx_buf,
+ unsigned int len);
+
+ int (*gpio_set_0_7)(struct rb4xx_cpld *self, u8 values);
+ int (*gpio_set_8)(struct rb4xx_cpld *self, u8 value);
+};