Message-ID: <dca2b64b040a18a2271527e3a79d70ea823cfd1c.camel@microchip.com>
Date:   Tue, 9 Aug 2022 09:42:52 +0000
From:   <Valentina.FernandezAlanis@...rochip.com>
To:     <Nagasuresh.Relli@...rochip.com>, <broonie@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <Conor.Dooley@...rochip.com>,
        <robh+dt@...nel.org>
CC:     <linux-spi@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 3/4] spi: microchip-core-qspi: Add support for
 microchip fpga qspi controllers

Tested-by: Valentina Fernandez <valentina.fernandezalanis@...rochip.com
>

On Mon, 2022-08-08 at 12:16 +0530, Naga Sureshkumar Relli wrote:
> Add a driver for Microchip FPGA QSPI controllers. This driver also
> supports "hard" QSPI controllers on Polarfire SoC.
> 
> Signed-off-by: Naga Sureshkumar Relli <nagasuresh.relli@...rochip.com
> >
> Reviewed-by: Conor Dooley <conor.dooley@...rochip.com>
> ---
>  drivers/spi/Kconfig                   |   9 +
>  drivers/spi/Makefile                  |   1 +
>  drivers/spi/spi-microchip-core-qspi.c | 600
> ++++++++++++++++++++++++++
>  3 files changed, 610 insertions(+)
>  create mode 100644 drivers/spi/spi-microchip-core-qspi.c
> 
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> index 9987c3f2bd1c..78e447327cc4 100644
> --- a/drivers/spi/Kconfig
> +++ b/drivers/spi/Kconfig
> @@ -591,6 +591,15 @@ config SPI_MICROCHIP_CORE
>  	  PolarFire SoC.
>  	  If built as a module, it will be called spi-microchip-core.
>  
> +config SPI_MICROCHIP_CORE_QSPI
> +	tristate "Microchip FPGA QSPI controllers"
> +	depends on SPI_MASTER
> +	help
> +	  This enables the QSPI driver for Microchip FPGA QSPI
> controllers.
> +	  Say Y or M here if you want to use the QSPI controllers on
> +	  PolarFire SoC.
> +	  If built as a module, it will be called spi-microchip-core-
> qspi.
> +
>  config SPI_MT65XX
>  	tristate "MediaTek SPI controller"
>  	depends on ARCH_MEDIATEK || COMPILE_TEST
> diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
> index 15d2f3835e45..4b34e855c841 100644
> --- a/drivers/spi/Makefile
> +++ b/drivers/spi/Makefile
> @@ -73,6 +73,7 @@ obj-$(CONFIG_SPI_LP8841_RTC)		+= spi-
> lp8841-rtc.o
>  obj-$(CONFIG_SPI_MESON_SPICC)		+= spi-meson-spicc.o
>  obj-$(CONFIG_SPI_MESON_SPIFC)		+= spi-meson-spifc.o
>  obj-$(CONFIG_SPI_MICROCHIP_CORE)	+= spi-microchip-core.o
> +obj-$(CONFIG_SPI_MICROCHIP_CORE_QSPI)	+= spi-microchip-core-
> qspi.o
>  obj-$(CONFIG_SPI_MPC512x_PSC)		+= spi-mpc512x-psc.o
>  obj-$(CONFIG_SPI_MPC52xx_PSC)		+= spi-mpc52xx-psc.o
>  obj-$(CONFIG_SPI_MPC52xx)		+= spi-mpc52xx.o
> diff --git a/drivers/spi/spi-microchip-core-qspi.c b/drivers/spi/spi-
> microchip-core-qspi.c
> new file mode 100644
> index 000000000000..19a6a46829f6
> --- /dev/null
> +++ b/drivers/spi/spi-microchip-core-qspi.c
> @@ -0,0 +1,600 @@
> +// SPDX-License-Identifier: (GPL-2.0)
> +/*
> + * Microchip coreQSPI QSPI controller driver
> + *
> + * Copyright (C) 2018-2022 Microchip Technology Inc. and its
> subsidiaries
> + *
> + * Author: Naga Sureshkumar Relli <nagasuresh.relli@...rochip.com>
> + *
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/spi/spi.h>
> +#include <linux/spi/spi-mem.h>
> +
> +/*
> + * QSPI Control register mask defines
> + */
> +#define CONTROL_ENABLE		BIT(0)
> +#define CONTROL_MASTER		BIT(1)
> +#define CONTROL_XIP		BIT(2)
> +#define CONTROL_XIPADDR		BIT(3)
> +#define CONTROL_CLKIDLE		BIT(10)
> +#define CONTROL_SAMPLE_MASK	GENMASK(12, 11)
> +#define CONTROL_MODE0		BIT(13)
> +#define CONTROL_MODE12_MASK	GENMASK(15, 14)
> +#define CONTROL_MODE12_EX_RO	BIT(14)
> +#define CONTROL_MODE12_EX_RW	BIT(15)
> +#define CONTROL_MODE12_FULL	GENMASK(15, 14)
> +#define CONTROL_FLAGSX4		BIT(16)
> +#define CONTROL_CLKRATE_MASK	GENMASK(27, 24)
> +#define CONTROL_CLKRATE_SHIFT	24
> +
> +/*
> + * QSPI Frames register mask defines
> + */
> +#define FRAMES_TOTALBYTES_MASK	GENMASK(15, 0)
> +#define FRAMES_CMDBYTES_MASK	GENMASK(24, 16)
> +#define FRAMES_CMDBYTES_SHIFT	16
> +#define FRAMES_SHIFT		25
> +#define FRAMES_IDLE_MASK	GENMASK(29, 26)
> +#define FRAMES_IDLE_SHIFT	26
> +#define FRAMES_FLAGBYTE		BIT(30)
> +#define FRAMES_FLAGWORD		BIT(31)
> +
> +/*
> + * QSPI Interrupt Enable register mask defines
> + */
> +#define IEN_TXDONE		BIT(0)
> +#define IEN_RXDONE		BIT(1)
> +#define IEN_RXAVAILABLE		BIT(2)
> +#define IEN_TXAVAILABLE		BIT(3)
> +#define IEN_RXFIFOEMPTY		BIT(4)
> +#define IEN_TXFIFOFULL		BIT(5)
> +
> +/*
> + * QSPI Status register mask defines
> + */
> +#define STATUS_TXDONE		BIT(0)
> +#define STATUS_RXDONE		BIT(1)
> +#define STATUS_RXAVAILABLE	BIT(2)
> +#define STATUS_TXAVAILABLE	BIT(3)
> +#define STATUS_RXFIFOEMPTY	BIT(4)
> +#define STATUS_TXFIFOFULL	BIT(5)
> +#define STATUS_READY		BIT(7)
> +#define STATUS_FLAGSX4		BIT(8)
> +#define STATUS_MASK		GENMASK(8, 0)
> +
> +#define BYTESUPPER_MASK		GENMASK(31, 16)
> +#define BYTESLOWER_MASK		GENMASK(15, 0)
> +
> +#define MAX_DIVIDER		16
> +#define MIN_DIVIDER		0
> +#define MAX_DATA_CMD_LEN	256
> +
> +/* QSPI ready time out value */
> +#define TIMEOUT_MS		500
> +
> +/*
> + * QSPI Register offsets.
> + */
> +#define REG_CONTROL		(0x00)
> +#define REG_FRAMES		(0x04)
> +#define REG_IEN			(0x0c)
> +#define REG_STATUS		(0x10)
> +#define REG_DIRECT_ACCESS	(0x14)
> +#define REG_UPPER_ACCESS	(0x18)
> +#define REG_RX_DATA		(0x40)
> +#define REG_TX_DATA		(0x44)
> +#define REG_X4_RX_DATA		(0x48)
> +#define REG_X4_TX_DATA		(0x4c)
> +#define REG_FRAMESUP		(0x50)
> +
> +/**
> + * struct mchp_coreqspi - Defines qspi driver instance
> + * @regs:              Virtual address of the QSPI controller
> registers
> + * @clk:               QSPI Operating clock
> + * @data_completion:   completion structure
> + * @op_lock:           lock access to the device
> + * @txbuf:             TX buffer
> + * @rxbuf:             RX buffer
> + * @irq:               IRQ number
> + * @tx_len:            Number of bytes left to transfer
> + * @rx_len:            Number of bytes left to receive
> + */
> +struct mchp_coreqspi {
> +	void __iomem *regs;
> +	struct clk *clk;
> +	struct completion data_completion;
> +	struct mutex op_lock; /* lock access to the device */
> +	u8 *txbuf;
> +	u8 *rxbuf;
> +	int irq;
> +	int tx_len;
> +	int rx_len;
> +};
> +
> +static int mchp_coreqspi_set_mode(struct mchp_coreqspi *qspi, const
> struct spi_mem_op *op)
> +{
> +	u32 control = readl_relaxed(qspi->regs + REG_CONTROL);
> +
> +	/*
> +	 * The operating mode can be configured based on the command
> that needs to be send.
> +	 * bits[15:14]: Sets whether multiple bit SPI operates in
> normal, extended or full modes.
> +	 *		00: Normal (single DQ0 TX and single DQ1 RX
> lines)
> +	 *		01: Extended RO (command and address bytes on
> DQ0 only)
> +	 *		10: Extended RW (command byte on DQ0 only)
> +	 *		11: Full. (command and address are on all DQ
> lines)
> +	 * bit[13]:	Sets whether multiple bit SPI uses 2 or 4
> bits of data
> +	 *		0: 2-bits (BSPI)
> +	 *		1: 4-bits (QSPI)
> +	 */
> +	if (op->data.buswidth == 4 || op->data.buswidth == 2) {
> +		control &= ~CONTROL_MODE12_MASK;
> +		if (op->cmd.buswidth == 1 && (op->addr.buswidth == 1 ||
> op->addr.buswidth == 0))
> +			control |= CONTROL_MODE12_EX_RO;
> +		else if (op->cmd.buswidth == 1)
> +			control |= CONTROL_MODE12_EX_RW;
> +		else
> +			control |= CONTROL_MODE12_FULL;
> +
> +		control |= CONTROL_MODE0;
> +	} else {
> +		control &= ~(CONTROL_MODE12_MASK |
> +			     CONTROL_MODE0);
> +	}
> +
> +	writel_relaxed(control, qspi->regs + REG_CONTROL);
> +
> +	return 0;
> +}
> +
> +static inline void mchp_coreqspi_read_op(struct mchp_coreqspi *qspi)
> +{
> +	u32 control, data;
> +
> +	if (!qspi->rx_len)
> +		return;
> +
> +	control = readl_relaxed(qspi->regs + REG_CONTROL);
> +
> +	/*
> +	 * Read 4-bytes from the SPI FIFO in single transaction and
> then read
> +	 * the reamaining data byte wise.
> +	 */
> +	control |= CONTROL_FLAGSX4;
> +	writel_relaxed(control, qspi->regs + REG_CONTROL);
> +
> +	while (qspi->rx_len >= 4) {
> +		while (readl_relaxed(qspi->regs + REG_STATUS) &
> STATUS_RXFIFOEMPTY)
> +			;
> +		data = readl_relaxed(qspi->regs + REG_X4_RX_DATA);
> +		*(u32 *)qspi->rxbuf = data;
> +		qspi->rxbuf += 4;
> +		qspi->rx_len -= 4;
> +	}
> +
> +	control &= ~CONTROL_FLAGSX4;
> +	writel_relaxed(control, qspi->regs + REG_CONTROL);
> +
> +	while (qspi->rx_len--) {
> +		while (readl_relaxed(qspi->regs + REG_STATUS) &
> STATUS_RXFIFOEMPTY)
> +			;
> +		data = readl_relaxed(qspi->regs + REG_RX_DATA);
> +		*qspi->rxbuf++ = (data & 0xFF);
> +	}
> +}
> +
> +static inline void mchp_coreqspi_write_op(struct mchp_coreqspi
> *qspi, bool word)
> +{
> +	u32 control, data;
> +
> +	control = readl_relaxed(qspi->regs + REG_CONTROL);
> +	control |= CONTROL_FLAGSX4;
> +	writel_relaxed(control, qspi->regs + REG_CONTROL);
> +
> +	while (qspi->tx_len >= 4) {
> +		while (readl_relaxed(qspi->regs + REG_STATUS) &
> STATUS_TXFIFOFULL)
> +			;
> +		data = *(u32 *)qspi->txbuf;
> +		qspi->txbuf += 4;
> +		qspi->tx_len -= 4;
> +		writel_relaxed(data, qspi->regs + REG_X4_TX_DATA);
> +	}
> +
> +	control &= ~CONTROL_FLAGSX4;
> +	writel_relaxed(control, qspi->regs + REG_CONTROL);
> +
> +	while (qspi->tx_len--) {
> +		while (readl_relaxed(qspi->regs + REG_STATUS) &
> STATUS_TXFIFOFULL)
> +			;
> +		data =  *qspi->txbuf++;
> +		writel_relaxed(data, qspi->regs + REG_TX_DATA);
> +	}
> +}
> +
> +static void mchp_coreqspi_enable_ints(struct mchp_coreqspi *qspi)
> +{
> +	u32 mask = IEN_TXDONE |
> +		   IEN_RXDONE |
> +		   IEN_RXAVAILABLE;
> +
> +	writel_relaxed(mask, qspi->regs + REG_IEN);
> +}
> +
> +static void mchp_coreqspi_disable_ints(struct mchp_coreqspi *qspi)
> +{
> +	writel_relaxed(0, qspi->regs + REG_IEN);
> +}
> +
> +static irqreturn_t mchp_coreqspi_isr(int irq, void *dev_id)
> +{
> +	struct mchp_coreqspi *qspi = (struct mchp_coreqspi *)dev_id;
> +	irqreturn_t ret = IRQ_NONE;
> +	int intfield = readl_relaxed(qspi->regs + REG_STATUS) &
> STATUS_MASK;
> +
> +	if (intfield == 0)
> +		return ret;
> +
> +	if (intfield & IEN_TXDONE) {
> +		writel_relaxed(IEN_TXDONE, qspi->regs + REG_STATUS);
> +		ret = IRQ_HANDLED;
> +	}
> +
> +	if (intfield & IEN_RXAVAILABLE) {
> +		writel_relaxed(IEN_RXAVAILABLE, qspi->regs +
> REG_STATUS);
> +		mchp_coreqspi_read_op(qspi);
> +		ret = IRQ_HANDLED;
> +	}
> +
> +	if (intfield & IEN_RXDONE) {
> +		writel_relaxed(IEN_RXDONE, qspi->regs + REG_STATUS);
> +		complete(&qspi->data_completion);
> +		ret = IRQ_HANDLED;
> +	}
> +
> +	return ret;
> +}
> +
> +static int mchp_coreqspi_setup_clock(struct mchp_coreqspi *qspi,
> struct spi_device *spi)
> +{
> +	unsigned long clk_hz;
> +	u32 control, baud_rate_val = 0;
> +
> +	clk_hz = clk_get_rate(qspi->clk);
> +	if (!clk_hz)
> +		return -EINVAL;
> +
> +	baud_rate_val = DIV_ROUND_UP(clk_hz, 2 * spi->max_speed_hz);
> +	if (baud_rate_val > MAX_DIVIDER || baud_rate_val < MIN_DIVIDER)
> {
> +		dev_err(&spi->dev,
> +			"could not configure the clock for spi clock %d
> Hz & system clock %ld Hz\n",
> +			spi->max_speed_hz, clk_hz);
> +		return -EINVAL;
> +	}
> +
> +	control = readl_relaxed(qspi->regs + REG_CONTROL);
> +	control |= baud_rate_val << CONTROL_CLKRATE_SHIFT;
> +	writel_relaxed(control, qspi->regs + REG_CONTROL);
> +	control = readl_relaxed(qspi->regs + REG_CONTROL);
> +
> +	if ((spi->mode & SPI_CPOL) && (spi->mode & SPI_CPHA))
> +		control |= CONTROL_CLKIDLE;
> +	else
> +		control &= ~CONTROL_CLKIDLE;
> +
> +	writel_relaxed(control, qspi->regs + REG_CONTROL);
> +
> +	return 0;
> +}
> +
> +static int mchp_coreqspi_setup_op(struct spi_device *spi_dev)
> +{
> +	struct spi_controller *ctlr = spi_dev->master;
> +	struct mchp_coreqspi *qspi = spi_controller_get_devdata(ctlr);
> +	u32 control = readl_relaxed(qspi->regs + REG_CONTROL);
> +
> +	control |= (CONTROL_MASTER | CONTROL_ENABLE);
> +	control &= ~CONTROL_CLKIDLE;
> +	writel_relaxed(control, qspi->regs + REG_CONTROL);
> +
> +	return 0;
> +}
> +
> +static inline void mchp_coreqspi_config_op(struct mchp_coreqspi
> *qspi, const struct spi_mem_op *op)
> +{
> +	u32 idle_cycles = 0;
> +	int total_bytes, cmd_bytes, frames, ctrl;
> +
> +	cmd_bytes = op->cmd.nbytes + op->addr.nbytes;
> +	total_bytes = cmd_bytes + op->data.nbytes;
> +
> +	/*
> +	 * As per the coreQSPI IP spec,the number of command and data
> bytes are
> +	 * controlled by the frames register for each SPI sequence.
> This supports
> +	 * the SPI flash memory read and writes sequences as below. so
> configure
> +	 * the cmd and total bytes accordingly.
> +	 * ------------------------------------------------------------
> ---------
> +	 * TOTAL BYTES  |  CMD BYTES | What
> happens                             |
> +	 *
> _____________________________________________________________________
> _
> +	 *              |            |                                 
>          |
> +	 *     1        |   1        | The SPI core will transmit a
> single byte |
> +	 *              |            | and receive data is
> discarded            |
> +	 *              |            |                                 
>          |
> +	 *     1        |   0        | The SPI core will transmit a
> single byte |
> +	 *              |            | and return a single
> byte                 |
> +	 *              |            |                                 
>          |
> +	 *     10       |   4        | The SPI core will transmit 4
> command     |
> +	 *              |            | bytes discarding the receive
> data and    |
> +	 *              |            | transmits 6 dummy bytes
> returning the 6  |
> +	 *              |            | received bytes and return a
> single byte  |
> +	 *              |            |                                 
>          |
> +	 *     10       |   10       | The SPI core will transmit 10
> command    |
> +	 *              |            |                                 
>          |
> +	 *     10       |    0       | The SPI core will transmit 10
> command    |
> +	 *              |            | bytes and returning 10 received
> bytes    |
> +	 *
> _____________________________________________________________________
> _
> +	 */
> +	if (!(op->data.dir == SPI_MEM_DATA_IN))
> +		cmd_bytes = total_bytes;
> +
> +	frames = total_bytes & BYTESUPPER_MASK;
> +	writel_relaxed(frames, qspi->regs + REG_FRAMESUP);
> +	frames = total_bytes & BYTESLOWER_MASK;
> +	frames |= cmd_bytes << FRAMES_CMDBYTES_SHIFT;
> +
> +	if (op->dummy.buswidth)
> +		idle_cycles = op->dummy.nbytes * 8 / op-
> >dummy.buswidth;
> +
> +	frames |= idle_cycles << FRAMES_IDLE_SHIFT;
> +	ctrl = readl_relaxed(qspi->regs + REG_CONTROL);
> +
> +	if (ctrl & CONTROL_MODE12_MASK)
> +		frames |= (1 << FRAMES_SHIFT);
> +
> +	frames |= FRAMES_FLAGWORD;
> +	writel_relaxed(frames, qspi->regs + REG_FRAMES);
> +}
> +
> +static int mchp_qspi_wait_for_ready(struct spi_mem *mem)
> +{
> +	struct mchp_coreqspi *qspi = spi_controller_get_devdata
> +				    (mem->spi->master);
> +	u32 status;
> +	int ret;
> +
> +	ret = readl_poll_timeout(qspi->regs + REG_STATUS, status,
> +				 (status & STATUS_READY), 0,
> +				 TIMEOUT_MS);
> +	if (ret) {
> +		dev_err(&mem->spi->dev,
> +			"Timeout waiting on QSPI ready.\n");
> +		return -ETIMEDOUT;
> +	}
> +
> +	return ret;
> +}
> +
> +static int mchp_coreqspi_exec_op(struct spi_mem *mem, const struct
> spi_mem_op *op)
> +{
> +	struct mchp_coreqspi *qspi = spi_controller_get_devdata
> +				    (mem->spi->master);
> +	u32 address = op->addr.val;
> +	u8 opcode = op->cmd.opcode;
> +	u8 opaddr[5];
> +	int err, i;
> +
> +	mutex_lock(&qspi->op_lock);
> +	err = mchp_qspi_wait_for_ready(mem);
> +	if (err)
> +		goto error;
> +
> +	err = mchp_coreqspi_setup_clock(qspi, mem->spi);
> +	if (err)
> +		goto error;
> +
> +	err = mchp_coreqspi_set_mode(qspi, op);
> +	if (err)
> +		goto error;
> +
> +	reinit_completion(&qspi->data_completion);
> +	mchp_coreqspi_config_op(qspi, op);
> +	if (op->cmd.opcode) {
> +		qspi->txbuf = &opcode;
> +		qspi->rxbuf = NULL;
> +		qspi->tx_len = op->cmd.nbytes;
> +		qspi->rx_len = 0;
> +		mchp_coreqspi_write_op(qspi, false);
> +	}
> +
> +	qspi->txbuf = &opaddr[0];
> +	if (op->addr.nbytes) {
> +		for (i = 0; i < op->addr.nbytes; i++)
> +			qspi->txbuf[i] = address >> (8 * (op-
> >addr.nbytes - i - 1));
> +
> +		qspi->rxbuf = NULL;
> +		qspi->tx_len = op->addr.nbytes;
> +		qspi->rx_len = 0;
> +		mchp_coreqspi_write_op(qspi, false);
> +	}
> +
> +	if (op->data.nbytes) {
> +		if (op->data.dir == SPI_MEM_DATA_OUT) {
> +			qspi->txbuf = (u8 *)op->data.buf.out;
> +			qspi->rxbuf = NULL;
> +			qspi->rx_len = 0;
> +			qspi->tx_len = op->data.nbytes;
> +			mchp_coreqspi_write_op(qspi, true);
> +		} else {
> +			qspi->txbuf = NULL;
> +			qspi->rxbuf = (u8 *)op->data.buf.in;
> +			qspi->rx_len = op->data.nbytes;
> +			qspi->tx_len = 0;
> +		}
> +	}
> +
> +	mchp_coreqspi_enable_ints(qspi);
> +
> +	if (!wait_for_completion_timeout(&qspi->data_completion,
> msecs_to_jiffies(1000)))
> +		err = -ETIMEDOUT;
> +
> +error:
> +	mutex_unlock(&qspi->op_lock);
> +	mchp_coreqspi_disable_ints(qspi);
> +
> +	return err;
> +}
> +
> +static bool mchp_coreqspi_supports_op(struct spi_mem *mem, const
> struct spi_mem_op *op)
> +{
> +	if (!spi_mem_default_supports_op(mem, op))
> +		return false;
> +
> +	if ((op->data.buswidth == 4 || op->data.buswidth == 2) &&
> +	    (op->cmd.buswidth == 1 && (op->addr.buswidth == 1 || op-
> >addr.buswidth == 0))) {
> +		/*
> +		 * If the command and address are on DQ0 only, then
> this
> +		 * controller doesn't support sending data on dual and
> +		 * quad lines. but it supports reading data on dual and
> +		 * quad lines with same configuration as command and
> +		 * address on DQ0.
> +		 * i.e. The control register[15:13] :EX_RO(read only)
> is
> +		 * meant only for the command and address are on DQ0
> but
> +		 * not to write data, it is just to read.
> +		 * Ex: 0x34h is Quad Load Program Data which is not
> +		 * supported. Then the spi-mem layer will iterate over
> +		 * each command and it will chose the supported one.
> +		 */
> +		if (op->data.dir == SPI_MEM_DATA_OUT)
> +			return false;
> +	}
> +
> +	return true;
> +}
> +
> +static int mchp_coreqspi_adjust_op_size(struct spi_mem *mem, struct
> spi_mem_op *op)
> +{
> +	if (op->data.dir == SPI_MEM_DATA_OUT || op->data.dir ==
> SPI_MEM_DATA_IN) {
> +		if (op->data.nbytes > MAX_DATA_CMD_LEN)
> +			op->data.nbytes = MAX_DATA_CMD_LEN;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct spi_controller_mem_ops mchp_coreqspi_mem_ops = {
> +	.adjust_op_size = mchp_coreqspi_adjust_op_size,
> +	.supports_op = mchp_coreqspi_supports_op,
> +	.exec_op = mchp_coreqspi_exec_op,
> +};
> +
> +static int mchp_coreqspi_probe(struct platform_device *pdev)
> +{
> +	struct spi_controller *ctlr;
> +	struct mchp_coreqspi *qspi;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	int ret;
> +
> +	ctlr = devm_spi_alloc_master(&pdev->dev, sizeof(*qspi));
> +	if (!ctlr)
> +		return dev_err_probe(&pdev->dev, -ENOMEM,
> +				     "unable to allocate master for
> QSPI controller\n");
> +
> +	qspi = spi_controller_get_devdata(ctlr);
> +	platform_set_drvdata(pdev, qspi);
> +
> +	qspi->regs = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(qspi->regs))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(qspi->regs),
> +				     "failed to map registers\n");
> +
> +	qspi->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(qspi->clk))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(qspi->clk),
> +				     "could not get clock\n");
> +
> +	ret = clk_prepare_enable(qspi->clk);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret,
> +				     "failed to enable clock\n");
> +
> +	init_completion(&qspi->data_completion);
> +	mutex_init(&qspi->op_lock);
> +
> +	qspi->irq = platform_get_irq(pdev, 0);
> +	if (qspi->irq < 0) {
> +		ret = qspi->irq;
> +		goto out;
> +	}
> +
> +	ret = devm_request_irq(&pdev->dev, qspi->irq,
> mchp_coreqspi_isr,
> +			       IRQF_SHARED, pdev->name, qspi);
> +	if (ret) {
> +		dev_err(&pdev->dev, "request_irq failed %d\n", ret);
> +		goto out;
> +	}
> +
> +	ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
> +	ctlr->mem_ops = &mchp_coreqspi_mem_ops;
> +	ctlr->setup = mchp_coreqspi_setup_op;
> +	ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_RX_DUAL |
> SPI_RX_QUAD |
> +			  SPI_TX_DUAL | SPI_TX_QUAD;
> +	ctlr->dev.of_node = np;
> +
> +	ret = devm_spi_register_controller(&pdev->dev, ctlr);
> +	if (ret) {
> +		dev_err_probe(&pdev->dev, ret,
> +			      "spi_register_controller failed\n");
> +		goto out;
> +	}
> +
> +	return 0;
> +
> +out:
> +	clk_disable_unprepare(qspi->clk);
> +
> +	return ret;
> +}
> +
> +static int mchp_coreqspi_remove(struct platform_device *pdev)
> +{
> +	struct mchp_coreqspi *qspi = platform_get_drvdata(pdev);
> +	u32 control = readl_relaxed(qspi->regs + REG_CONTROL);
> +
> +	mchp_coreqspi_disable_ints(qspi);
> +	control &= ~CONTROL_ENABLE;
> +	writel_relaxed(control, qspi->regs + REG_CONTROL);
> +	clk_disable_unprepare(qspi->clk);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id mchp_coreqspi_of_match[] = {
> +	{ .compatible = "microchip,coreqspi-rtl-v2" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, mchp_coreqspi_of_match);
> +
> +static struct platform_driver mchp_coreqspi_driver = {
> +	.probe = mchp_coreqspi_probe,
> +	.driver = {
> +		.name = "microchip,coreqspi",
> +		.of_match_table = mchp_coreqspi_of_match,
> +	},
> +	.remove = mchp_coreqspi_remove,
> +};
> +module_platform_driver(mchp_coreqspi_driver);
> +
> +MODULE_AUTHOR("Naga Sureshkumar Relli <
> nagasuresh.relli@...rochip.com");
> +MODULE_DESCRIPTION("Microchip coreQSPI QSPI controller driver");
> +MODULE_LICENSE("GPL");

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