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Date:   Thu, 1 Aug 2019 08:22:33 +0200
From:   Boris Brezillon <boris.brezillon@collabora.com>
To:     Mason Yang <masonccyang@mxic.com.tw>
Cc:     miquel.raynal@bootlin.com, marek.vasut@gmail.com,
        bbrezillon@kernel.org, dwmw2@infradead.org,
        computersforpeace@gmail.com, vigneshr@ti.com, richard@nod.at,
        robh+dt@kernel.org, stefan@agner.ch, mark.rutland@arm.com,
        linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
        juliensu@mxic.com.tw, paul.burton@mips.com, liang.yang@amlogic.com,
        lee.jones@linaro.org, anders.roxell@linaro.org,
        christophe.kerello@st.com, paul@crapouillou.net,
        devicetree@vger.kernel.org
Subject: Re: [PATCH v6 1/2] mtd: rawnand: Add Macronix raw NAND controller
 driver
Message-ID: <20190801082233.759f6ae9@collabora.com>
In-Reply-To: <1564631710-30276-2-git-send-email-masonccyang@mxic.com.tw>
References: <1564631710-30276-1-git-send-email-masonccyang@mxic.com.tw>
        <1564631710-30276-2-git-send-email-masonccyang@mxic.com.tw>
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On Thu,  1 Aug 2019 11:55:09 +0800
Mason Yang <masonccyang@mxic.com.tw> wrote:

> Add a driver for Macronix raw NAND controller.
> 
> Signed-off-by: Mason Yang <masonccyang@mxic.com.tw>
> ---
>  drivers/mtd/nand/raw/Kconfig     |   6 +
>  drivers/mtd/nand/raw/Makefile    |   1 +
>  drivers/mtd/nand/raw/mxic_nand.c | 554 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 561 insertions(+)
>  create mode 100644 drivers/mtd/nand/raw/mxic_nand.c
> 
> diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
> index 5a711d8..9cff36a 100644
> --- a/drivers/mtd/nand/raw/Kconfig
> +++ b/drivers/mtd/nand/raw/Kconfig
> @@ -407,6 +407,12 @@ config MTD_NAND_MTK
>  	  Enables support for NAND controller on MTK SoCs.
>  	  This controller is found on mt27xx, mt81xx, mt65xx SoCs.
>  
> +config MTD_NAND_MXIC
> +	tristate "Macronix raw NAND controller"
> +	depends on HAS_IOMEM || COMPILE_TEST
> +	help
> +	  This selects the Macronix raw NAND controller driver.
> +
>  config MTD_NAND_TEGRA
>  	tristate "NVIDIA Tegra NAND controller"
>  	depends on ARCH_TEGRA || COMPILE_TEST
> diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
> index efaf5cd..9b43fbf 100644
> --- a/drivers/mtd/nand/raw/Makefile
> +++ b/drivers/mtd/nand/raw/Makefile
> @@ -54,6 +54,7 @@ obj-$(CONFIG_MTD_NAND_HISI504)	        += hisi504_nand.o
>  obj-$(CONFIG_MTD_NAND_BRCMNAND)		+= brcmnand/
>  obj-$(CONFIG_MTD_NAND_QCOM)		+= qcom_nandc.o
>  obj-$(CONFIG_MTD_NAND_MTK)		+= mtk_ecc.o mtk_nand.o
> +obj-$(CONFIG_MTD_NAND_MXIC)		+= mxic_nand.o
>  obj-$(CONFIG_MTD_NAND_TEGRA)		+= tegra_nand.o
>  obj-$(CONFIG_MTD_NAND_STM32_FMC2)	+= stm32_fmc2_nand.o
>  obj-$(CONFIG_MTD_NAND_MESON)		+= meson_nand.o
> diff --git a/drivers/mtd/nand/raw/mxic_nand.c b/drivers/mtd/nand/raw/mxic_nand.c
> new file mode 100644
> index 0000000..56e816d
> --- /dev/null
> +++ b/drivers/mtd/nand/raw/mxic_nand.c
> @@ -0,0 +1,554 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019 Macronix International Co., Ltd.
> + *
> + * Author:
> + *	Mason Yang <masonccyang@mxic.com.tw>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/rawnand.h>
> +#include <linux/mtd/nand_ecc.h>
> +#include <linux/platform_device.h>
> +
> +#include "internals.h"
> +
> +#define HC_CFG			0x0
> +#define HC_CFG_IF_CFG(x)	((x) << 27)
> +#define HC_CFG_DUAL_SLAVE	BIT(31)
> +#define HC_CFG_INDIVIDUAL	BIT(30)
> +#define HC_CFG_NIO(x)		(((x) / 4) << 27)
> +#define HC_CFG_TYPE(s, t)	((t) << (23 + ((s) * 2)))
> +#define HC_CFG_TYPE_SPI_NOR	0
> +#define HC_CFG_TYPE_SPI_NAND	1
> +#define HC_CFG_TYPE_SPI_RAM	2
> +#define HC_CFG_TYPE_RAW_NAND	3
> +#define HC_CFG_SLV_ACT(x)	((x) << 21)
> +#define HC_CFG_CLK_PH_EN	BIT(20)
> +#define HC_CFG_CLK_POL_INV	BIT(19)
> +#define HC_CFG_BIG_ENDIAN	BIT(18)
> +#define HC_CFG_DATA_PASS	BIT(17)
> +#define HC_CFG_IDLE_SIO_LVL(x)	((x) << 16)
> +#define HC_CFG_MAN_START_EN	BIT(3)
> +#define HC_CFG_MAN_START	BIT(2)
> +#define HC_CFG_MAN_CS_EN	BIT(1)
> +#define HC_CFG_MAN_CS_ASSERT	BIT(0)
> +
> +#define INT_STS			0x4
> +#define INT_STS_EN		0x8
> +#define INT_SIG_EN		0xc
> +#define INT_STS_ALL		GENMASK(31, 0)
> +#define INT_RDY_PIN		BIT(26)
> +#define INT_RDY_SR		BIT(25)
> +#define INT_LNR_SUSP		BIT(24)
> +#define INT_ECC_ERR		BIT(17)
> +#define INT_CRC_ERR		BIT(16)
> +#define INT_LWR_DIS		BIT(12)
> +#define INT_LRD_DIS		BIT(11)
> +#define INT_SDMA_INT		BIT(10)
> +#define INT_DMA_FINISH		BIT(9)
> +#define INT_RX_NOT_FULL		BIT(3)
> +#define INT_RX_NOT_EMPTY	BIT(2)
> +#define INT_TX_NOT_FULL		BIT(1)
> +#define INT_TX_EMPTY		BIT(0)
> +
> +#define HC_EN			0x10
> +#define HC_EN_BIT		BIT(0)
> +
> +#define TXD(x)			(0x14 + ((x) * 4))
> +#define RXD			0x24
> +
> +#define SS_CTRL(s)		(0x30 + ((s) * 4))
> +#define LRD_CFG			0x44
> +#define LWR_CFG			0x80
> +#define RWW_CFG			0x70
> +#define OP_READ			BIT(23)
> +#define OP_DUMMY_CYC(x)		((x) << 17)
> +#define OP_ADDR_BYTES(x)	((x) << 14)
> +#define OP_CMD_BYTES(x)		(((x) - 1) << 13)
> +#define OP_OCTA_CRC_EN		BIT(12)
> +#define OP_DQS_EN		BIT(11)
> +#define OP_ENHC_EN		BIT(10)
> +#define OP_PREAMBLE_EN		BIT(9)
> +#define OP_DATA_DDR		BIT(8)
> +#define OP_DATA_BUSW(x)		((x) << 6)
> +#define OP_ADDR_DDR		BIT(5)
> +#define OP_ADDR_BUSW(x)		((x) << 3)
> +#define OP_CMD_DDR		BIT(2)
> +#define OP_CMD_BUSW(x)		(x)
> +#define OP_BUSW_1		0
> +#define OP_BUSW_2		1
> +#define OP_BUSW_4		2
> +#define OP_BUSW_8		3
> +
> +#define OCTA_CRC		0x38
> +#define OCTA_CRC_IN_EN(s)	BIT(3 + ((s) * 16))
> +#define OCTA_CRC_CHUNK(s, x)	((fls((x) / 32)) << (1 + ((s) * 16)))
> +#define OCTA_CRC_OUT_EN(s)	BIT(0 + ((s) * 16))
> +
> +#define ONFI_DIN_CNT(s)		(0x3c + (s))
> +
> +#define LRD_CTRL		0x48
> +#define RWW_CTRL		0x74
> +#define LWR_CTRL		0x84
> +#define LMODE_EN		BIT(31)
> +#define LMODE_SLV_ACT(x)	((x) << 21)
> +#define LMODE_CMD1(x)		((x) << 8)
> +#define LMODE_CMD0(x)		(x)
> +
> +#define LRD_ADDR		0x4c
> +#define LWR_ADDR		0x88
> +#define LRD_RANGE		0x50
> +#define LWR_RANGE		0x8c
> +
> +#define AXI_SLV_ADDR		0x54
> +
> +#define DMAC_RD_CFG		0x58
> +#define DMAC_WR_CFG		0x94
> +#define DMAC_CFG_PERIPH_EN	BIT(31)
> +#define DMAC_CFG_ALLFLUSH_EN	BIT(30)
> +#define DMAC_CFG_LASTFLUSH_EN	BIT(29)
> +#define DMAC_CFG_QE(x)		(((x) + 1) << 16)
> +#define DMAC_CFG_BURST_LEN(x)	(((x) + 1) << 12)
> +#define DMAC_CFG_BURST_SZ(x)	((x) << 8)
> +#define DMAC_CFG_DIR_READ	BIT(1)
> +#define DMAC_CFG_START		BIT(0)
> +
> +#define DMAC_RD_CNT		0x5c
> +#define DMAC_WR_CNT		0x98
> +
> +#define SDMA_ADDR		0x60
> +
> +#define DMAM_CFG		0x64
> +#define DMAM_CFG_START		BIT(31)
> +#define DMAM_CFG_CONT		BIT(30)
> +#define DMAM_CFG_SDMA_GAP(x)	(fls((x) / 8192) << 2)
> +#define DMAM_CFG_DIR_READ	BIT(1)
> +#define DMAM_CFG_EN		BIT(0)
> +
> +#define DMAM_CNT		0x68
> +
> +#define LNR_TIMER_TH		0x6c
> +
> +#define RDM_CFG0		0x78
> +#define RDM_CFG0_POLY(x)	(x)
> +
> +#define RDM_CFG1		0x7c
> +#define RDM_CFG1_RDM_EN		BIT(31)
> +#define RDM_CFG1_SEED(x)	(x)
> +
> +#define LWR_SUSP_CTRL		0x90
> +#define LWR_SUSP_CTRL_EN	BIT(31)
> +
> +#define DMAS_CTRL		0x9c
> +#define DMAS_CTRL_EN		BIT(31)
> +#define DMAS_CTRL_DIR_READ	BIT(30)
> +
> +#define DATA_STROB		0xa0
> +#define DATA_STROB_EDO_EN	BIT(2)
> +#define DATA_STROB_INV_POL	BIT(1)
> +#define DATA_STROB_DELAY_2CYC	BIT(0)
> +
> +#define IDLY_CODE(x)		(0xa4 + ((x) * 4))
> +#define IDLY_CODE_VAL(x, v)	((v) << (((x) % 4) * 8))
> +
> +#define GPIO			0xc4
> +#define GPIO_PT(x)		BIT(3 + ((x) * 16))
> +#define GPIO_RESET(x)		BIT(2 + ((x) * 16))
> +#define GPIO_HOLDB(x)		BIT(1 + ((x) * 16))
> +#define GPIO_WPB(x)		BIT((x) * 16)
> +
> +#define HC_VER			0xd0
> +
> +#define HW_TEST(x)		(0xe0 + ((x) * 4))
> +
> +#define MXIC_NFC_MAX_CLK_HZ	50000000
> +
> +struct mxic_nand_ctlr {
> +	struct clk *ps_clk;
> +	struct clk *send_clk;
> +	struct clk *send_dly_clk;
> +	void __iomem *regs;
> +	struct nand_controller controller;
> +	struct device *dev;
> +	void *priv;

Looks like this priv field point to a nand_chip object. Please replace
it by:

	struct nand_chip *chip;

> +};
> +
> +struct mxic_nand_chip {
> +	struct nand_chip chip;
> +};

No need to define your own nand_chip struct if all it contains is the
base definition.

> +
> +static int mxic_nfc_clk_enable(struct mxic_nand_ctlr *nfc)
> +{
> +	int ret;
> +
> +	ret = clk_prepare_enable(nfc->ps_clk);
> +	if (ret)
> +		return ret;
> +
> +	ret = clk_prepare_enable(nfc->send_clk);
> +	if (ret)
> +		goto err_ps_clk;
> +
> +	ret = clk_prepare_enable(nfc->send_dly_clk);
> +	if (ret)
> +		goto err_send_dly_clk;
> +
> +	return ret;
> +
> +err_send_dly_clk:
> +	clk_disable_unprepare(nfc->send_clk);
> +err_ps_clk:
> +	clk_disable_unprepare(nfc->ps_clk);
> +
> +	return ret;
> +}
> +
> +static void mxic_nfc_clk_disable(struct mxic_nand_ctlr *nfc)
> +{
> +	clk_disable_unprepare(nfc->send_clk);
> +	clk_disable_unprepare(nfc->send_dly_clk);
> +	clk_disable_unprepare(nfc->ps_clk);
> +}
> +
> +static void mxic_nfc_set_input_delay(struct mxic_nand_ctlr *nfc, u8 idly_code)
> +{
> +	writel(IDLY_CODE_VAL(0, idly_code) |
> +	       IDLY_CODE_VAL(1, idly_code) |
> +	       IDLY_CODE_VAL(2, idly_code) |
> +	       IDLY_CODE_VAL(3, idly_code),
> +	       nfc->regs + IDLY_CODE(0));
> +	writel(IDLY_CODE_VAL(4, idly_code) |
> +	       IDLY_CODE_VAL(5, idly_code) |
> +	       IDLY_CODE_VAL(6, idly_code) |
> +	       IDLY_CODE_VAL(7, idly_code),
> +	       nfc->regs + IDLY_CODE(1));
> +}
> +
> +static int mxic_nfc_clk_setup(struct mxic_nand_ctlr *nfc, unsigned long freq)
> +{
> +	int ret;
> +
> +	ret = clk_set_rate(nfc->send_clk, freq);
> +	if (ret)
> +		return ret;
> +
> +	ret = clk_set_rate(nfc->send_dly_clk, freq);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * A constant delay range from 0x0 ~ 0x1F for input delay,
> +	 * the unit is 78 ps, the max input delay is 2.418 ns.
> +	 */
> +	mxic_nfc_set_input_delay(nfc, 0xf);

Just curious. Shouldn't we use that to support EDO modes? This being
said, a delay of 2.5ns will not be enough for EDO...

> +
> +	/*
> +	 * Phase degree = 360 * freq * output-delay
> +	 * where output-delay is a constant value 1 ns in FPGA.
> +	 *
> +	 * Get Phase degree = 360 * freq * 1 ns
> +	 *                  = 360 * freq * 1 sec / 1000000000
> +	 *                  = 9 * freq / 25000000
> +	 */
> +	ret = clk_set_phase(nfc->send_dly_clk, 9 * freq / 25000000);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int mxic_nfc_set_freq(struct mxic_nand_ctlr *nfc, unsigned long freq)
> +{
> +	int ret;
> +
> +	if (freq > MXIC_NFC_MAX_CLK_HZ)
> +		freq = MXIC_NFC_MAX_CLK_HZ;
> +
> +	mxic_nfc_clk_disable(nfc);
> +	ret = mxic_nfc_clk_setup(nfc, freq);
> +	if (ret)
> +		return ret;
> +
> +	ret = mxic_nfc_clk_enable(nfc);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static void mxic_nfc_hw_init(struct mxic_nand_ctlr *nfc)
> +{
> +	writel(DATA_STROB_EDO_EN, nfc->regs + DATA_STROB);

Oh, no, here is the EDO flag. BTW, you should not have it set by
default, it's something you configure in your ->setup_data_interface()
implementation.

> +	writel(HC_CFG_NIO(8) | HC_CFG_TYPE(1, HC_CFG_TYPE_RAW_NAND) |
> +	       HC_CFG_SLV_ACT(0) | HC_CFG_MAN_CS_EN |
> +	       HC_CFG_IDLE_SIO_LVL(1), nfc->regs + HC_CFG);
> +	writel(INT_STS_ALL, nfc->regs + INT_STS_EN);
> +	writel(0x0, nfc->regs + ONFI_DIN_CNT(0));
> +	writel(0, nfc->regs + LRD_CFG);
> +	writel(0, nfc->regs + LRD_CTRL);
> +	writel(0x0, nfc->regs + HC_EN);
> +
> +	/* Default 10 MHz to setup tRC_min/tWC_min:100 ns */
> +	mxic_nfc_set_freq(nfc, 10000000);

Again, not something you should configure here, but I guess having a
default setting does not hurt.

> +}
> +
> +static void mxic_nfc_cs_enable(struct mxic_nand_ctlr *nfc)
> +{
> +	writel(readl(nfc->regs + HC_CFG) | HC_CFG_MAN_CS_EN,
> +	       nfc->regs + HC_CFG);
> +	writel(HC_CFG_MAN_CS_ASSERT | readl(nfc->regs + HC_CFG),
> +	       nfc->regs + HC_CFG);
> +}
> +
> +static void mxic_nfc_cs_disable(struct mxic_nand_ctlr *nfc)
> +{
> +	writel(~HC_CFG_MAN_CS_ASSERT & readl(nfc->regs + HC_CFG),
> +	       nfc->regs + HC_CFG);
> +}
> +
> +static int  mxic_nfc_wait_ready(struct nand_chip *chip)
> +{
> +	struct mxic_nand_ctlr *nfc = nand_get_controller_data(chip);
> +	u32 sts;
> +
> +	return readl_poll_timeout(nfc->regs + INT_STS, sts,
> +				  sts & INT_RDY_PIN, 0, USEC_PER_SEC);

You're not using interrupts at all? For things like R/B wait it's
usually a good thing to rely on interrupts instead of status-polling.

> +}
> +
> +static int mxic_nfc_data_xfer(struct mxic_nand_ctlr *nfc, const void *txbuf,
> +			      void *rxbuf, unsigned int len)
> +{
> +	unsigned int pos = 0;
> +
> +	while (pos < len) {
> +		unsigned int nbytes = len - pos;
> +		u32 data = 0xffffffff;
> +		u32 sts;
> +		int ret;
> +
> +		if (nbytes > 4)
> +			nbytes = 4;
> +
> +		if (txbuf)
> +			memcpy(&data, txbuf + pos, nbytes);
> +
> +		ret = readl_poll_timeout(nfc->regs + INT_STS, sts,
> +					 sts & INT_TX_EMPTY, 0, USEC_PER_SEC);
> +		if (ret)
> +			return ret;
> +
> +		writel(data, nfc->regs + TXD(nbytes % 4));
> +
> +		ret = readl_poll_timeout(nfc->regs + INT_STS, sts,
> +					 sts & INT_TX_EMPTY, 0,
> +					 USEC_PER_SEC);
> +		if (ret)
> +			return ret;
> +
> +		ret = readl_poll_timeout(nfc->regs + INT_STS, sts,
> +					 sts & INT_RX_NOT_EMPTY, 0,
> +					 USEC_PER_SEC);
> +		if (ret)
> +			return ret;
> +
> +		data = readl(nfc->regs + RXD);
> +		if (rxbuf) {
> +			data >>= (8 * (4 - nbytes));
> +			memcpy(rxbuf + pos, &data, nbytes);
> +		}
> +		if (readl(nfc->regs + INT_STS) & INT_RX_NOT_EMPTY)
> +			dev_warn(nfc->dev, "RX FIFO not empty\n")
> +
> +		pos += nbytes;
> +	}
> +
> +	return 0;
> +}
> +
> +static int mxic_nfc_exec_op(struct nand_chip *chip,
> +			    const struct nand_operation *op, bool check_only)
> +{
> +	struct mxic_nand_ctlr *nfc = nand_get_controller_data(chip);
> +	const struct nand_op_instr *instr = NULL;
> +	int ret = 0;
> +	unsigned int op_id;
> +
> +	mxic_nfc_cs_enable(nfc);
> +	for (op_id = 0; op_id < op->ninstrs; op_id++) {
> +		instr = &op->instrs[op_id];
> +
> +		switch (instr->type) {
> +		case NAND_OP_CMD_INSTR:
> +			writel(0, nfc->regs + HC_EN);
> +			writel(HC_EN_BIT, nfc->regs + HC_EN);
> +			writel(OP_CMD_BUSW(OP_BUSW_8) |  OP_DUMMY_CYC(0x3F) |
> +			       OP_CMD_BYTES(0), nfc->regs + SS_CTRL(0));
> +
> +			ret = mxic_nfc_data_xfer(nfc,
> +						 &instr->ctx.cmd.opcode,
> +						 NULL, 1);
> +			break;
> +
> +		case NAND_OP_ADDR_INSTR:
> +			writel(OP_ADDR_BUSW(OP_BUSW_8) | OP_DUMMY_CYC(0x3F) |
> +			       OP_ADDR_BYTES(instr->ctx.addr.naddrs),
> +			       nfc->regs + SS_CTRL(0));
> +			ret = mxic_nfc_data_xfer(nfc,
> +						 instr->ctx.addr.addrs, NULL,
> +						 instr->ctx.addr.naddrs);
> +			break;
> +
> +		case NAND_OP_DATA_IN_INSTR:
> +			writel(0x0, nfc->regs + ONFI_DIN_CNT(0));
> +			writel(OP_DATA_BUSW(OP_BUSW_8) | OP_DUMMY_CYC(0x3F) |
> +			       OP_READ, nfc->regs + SS_CTRL(0));
> +			ret = mxic_nfc_data_xfer(nfc, NULL,
> +						 instr->ctx.data.buf.in,
> +						 instr->ctx.data.len);
> +			break;
> +
> +		case NAND_OP_DATA_OUT_INSTR:
> +			writel(instr->ctx.data.len,
> +			       nfc->regs + ONFI_DIN_CNT(0));
> +			writel(OP_DATA_BUSW(OP_BUSW_8) | OP_DUMMY_CYC(0x3F),
> +			       nfc->regs + SS_CTRL(0));
> +			ret = mxic_nfc_data_xfer(nfc,
> +						 instr->ctx.data.buf.out, NULL,
> +						 instr->ctx.data.len);
> +			break;
> +
> +		case NAND_OP_WAITRDY_INSTR:
> +			ret = mxic_nfc_wait_ready(chip);
> +			break;
> +		}
> +	}
> +	mxic_nfc_cs_disable(nfc);
> +
> +	return ret;
> +}
> +
> +static int mxic_nfc_setup_data_interface(struct nand_chip *chip, int chipnr,
> +					 const struct nand_data_interface *conf)
> +{
> +	struct mxic_nand_ctlr *nfc = nand_get_controller_data(chip);
> +	const struct nand_sdr_timings *sdr;
> +	unsigned long freq;
> +
> +	sdr = nand_get_sdr_timings(conf);
> +	if (IS_ERR(sdr))
> +		return PTR_ERR(sdr);
> +
> +	if (chipnr < 0)

Please use the NAND_DATA_IFACE_CHECK_ONLY macro for this check:

	if (chipnr == NAND_DATA_IFACE_CHECK_ONLY)
		return 0;

> +		return 0;
> +
> +	if (sdr->tRC_min)
> +		freq = 1000000000 / (sdr->tRC_min / 1000);

Please use NSEC_PER_SEC instead of 1000000000. And I think you can get
rid of the check on sdr->tRC_min (it should never be 0).

> +
> +	return mxic_nfc_set_freq(nfc, freq);

You should set the EDO when ->tRC_min < 30000 IIRC, clear it otherwise.

> +}
> +
> +static const struct nand_controller_ops mxic_nand_controller_ops = {
> +	.exec_op = mxic_nfc_exec_op,
> +	.setup_data_interface = mxic_nfc_setup_data_interface,
> +};
> +
> +static int mxic_nfc_probe(struct platform_device *pdev)
> +{
> +	struct mtd_info *mtd;
> +	struct mxic_nand_ctlr *nfc;
> +	struct mxic_nand_chip *mxic_nand;
> +	struct nand_chip *nand_chip;
> +	struct resource *res;
> +	int err;
> +
> +	nfc = devm_kzalloc(&pdev->dev, sizeof(struct mxic_nand_ctlr),
> +			   GFP_KERNEL);
> +	if (!nfc)
> +		return -ENOMEM;
> +
> +	mxic_nand = devm_kzalloc(&pdev->dev, sizeof(struct mxic_nand_chip),
> +				 GFP_KERNEL);
> +	if (!mxic_nand)
> +		return -ENOMEM;
> +
> +	nfc->ps_clk = devm_clk_get(&pdev->dev, "ps");
> +	if (IS_ERR(nfc->ps_clk))
> +		return PTR_ERR(nfc->ps_clk);
> +
> +	nfc->send_clk = devm_clk_get(&pdev->dev, "send");
> +	if (IS_ERR(nfc->send_clk))
> +		return PTR_ERR(nfc->send_clk);
> +
> +	nfc->send_dly_clk = devm_clk_get(&pdev->dev, "send_dly");
> +	if (IS_ERR(nfc->send_dly_clk))
> +		return PTR_ERR(nfc->send_dly_clk);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	nfc->regs = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(nfc->regs))
> +		return PTR_ERR(nfc->regs);
> +
> +	nand_chip = &mxic_nand->chip;
> +	mtd = nand_to_mtd(nand_chip);
> +	mtd->dev.parent = &pdev->dev;
> +	nand_chip->ecc.priv = NULL;

No need to do this NULL assignment, the object is allocated with
devm_kzalloc().

> +	nand_set_flash_node(nand_chip, pdev->dev.of_node);

The flash node should be a child of pdev->dev.of_node,
pdev->dev.of_node is representing your controller not the NAND chip.

> +	nand_chip->priv = nfc;
> +	nfc->dev = &pdev->dev;
> +	nfc->priv = nand_chip;
> +
> +	nfc->controller.ops = &mxic_nand_controller_ops;
> +	nand_controller_init(&nfc->controller);
> +	nand_chip->controller = &nfc->controller;
> +
> +	mxic_nfc_hw_init(nfc);
> +
> +	err = nand_scan(nand_chip, 1);
> +	if (err)
> +		goto fail;
> +
> +	err = mtd_device_register(mtd, NULL, 0);
> +	if (err)
> +		goto fail;
> +
> +	platform_set_drvdata(pdev, nfc);
> +	return 0;
> +
> +fail:
> +	mxic_nfc_clk_disable(nfc);

Looks like you never call mxic_nfc_clk_enable(), which means you'll end
up with unbalanced prepare/enable counts. Also not sure how that can
work unless the bootloader takes care of enabling the clks for you.

> +	return err;
> +}
> +
> +static int mxic_nfc_remove(struct platform_device *pdev)
> +{
> +	struct mxic_nand_ctlr *nfc = platform_get_drvdata(pdev);
> +
> +	nand_release(nfc->priv);
> +	mxic_nfc_clk_disable(nfc);
> +	return 0;
> +}
> +
> +static const struct of_device_id mxic_nfc_of_ids[] = {
> +	{ .compatible = "mxicy,multi-itfc-v009-nand-morph", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, mxic_nfc_of_ids);
> +
> +static struct platform_driver mxic_nfc_driver = {
> +	.probe = mxic_nfc_probe,
> +	.remove = mxic_nfc_remove,
> +	.driver = {
> +		.name = "mxic-nfc",
> +		.of_match_table = mxic_nfc_of_ids,
> +	},
> +};
> +module_platform_driver(mxic_nfc_driver);
> +
> +MODULE_AUTHOR("Mason Yang <masonccyang@mxic.com.tw>");
> +MODULE_DESCRIPTION("Macronix raw NAND controller driver");
> +MODULE_LICENSE("GPL v2");