drivers/spi/spi-dw-mmio.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Memory-mapped interface driver for DW SPI Core
  *
  * Copyright (c) 2010, Octasic semiconductor.
  */

 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
 #include <linux/scatterlist.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/acpi.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>

 #include "spi-dw.h"

 #define DRIVER_NAME "dw_spi_mmio"

 struct dw_spi_mmio {
 	struct dw_spi  dws;
 	struct clk     *clk;
 	struct clk     *pclk;
 	void           *priv;
 	struct reset_control *rstc;
 };

 #define MSCC_CPU_SYSTEM_CTRL_GENERAL_CTRL	0x24
 #define OCELOT_IF_SI_OWNER_OFFSET		4
 #define JAGUAR2_IF_SI_OWNER_OFFSET		6
 #define MSCC_IF_SI_OWNER_MASK			GENMASK(1, 0)
 #define MSCC_IF_SI_OWNER_SISL			0
 #define MSCC_IF_SI_OWNER_SIBM			1
 #define MSCC_IF_SI_OWNER_SIMC			2

 #define MSCC_SPI_MST_SW_MODE			0x14
 #define MSCC_SPI_MST_SW_MODE_SW_PIN_CTRL_MODE	BIT(13)
 #define MSCC_SPI_MST_SW_MODE_SW_SPI_CS(x)	(x << 5)

 #define SPARX5_FORCE_ENA			0xa4
 #define SPARX5_FORCE_VAL			0xa8

 struct dw_spi_mscc {
 	struct regmap       *syscon;
 	void __iomem        *spi_mst; /* Not sparx5 */
 };

 /*
  * Elba SoC does not use ssi, pin override is used for cs 0,1 and
  * gpios for cs 2,3 as defined in the device tree.
  *
  * cs:  |       1               0
  * bit: |---3-------2-------1-------0
  *      |  cs1   cs1_ovr   cs0   cs0_ovr
  */
 #define ELBA_SPICS_REG			0x2468
 #define ELBA_SPICS_OFFSET(cs)		((cs) << 1)
 #define ELBA_SPICS_MASK(cs)		(GENMASK(1, 0) << ELBA_SPICS_OFFSET(cs))
 #define ELBA_SPICS_SET(cs, val)		\
 		((((val) << 1) | BIT(0)) << ELBA_SPICS_OFFSET(cs))

 /*
  * The Designware SPI controller (referred to as master in the documentation)
  * automatically deasserts chip select when the tx fifo is empty. The chip
  * selects then needs to be either driven as GPIOs or, for the first 4 using
  * the SPI boot controller registers. the final chip select is an OR gate
  * between the Designware SPI controller and the SPI boot controller.
  */
 static void dw_spi_mscc_set_cs(struct spi_device *spi, bool enable)
 {
 	struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
 	struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
 	struct dw_spi_mscc *dwsmscc = dwsmmio->priv;
 	u32 cs = spi_get_chipselect(spi, 0);

 	if (cs < 4) {
 		u32 sw_mode = MSCC_SPI_MST_SW_MODE_SW_PIN_CTRL_MODE;

 		if (!enable)
 			sw_mode |= MSCC_SPI_MST_SW_MODE_SW_SPI_CS(BIT(cs));

 		writel(sw_mode, dwsmscc->spi_mst + MSCC_SPI_MST_SW_MODE);
 	}

 	dw_spi_set_cs(spi, enable);
 }

 static int dw_spi_mscc_init(struct platform_device *pdev,
 			    struct dw_spi_mmio *dwsmmio,
 			    const char *cpu_syscon, u32 if_si_owner_offset)
 {
 	struct dw_spi_mscc *dwsmscc;

 	dwsmscc = devm_kzalloc(&pdev->dev, sizeof(*dwsmscc), GFP_KERNEL);
 	if (!dwsmscc)
 		return -ENOMEM;

 	dwsmscc->spi_mst = devm_platform_ioremap_resource(pdev, 1);
 	if (IS_ERR(dwsmscc->spi_mst)) {
 		dev_err(&pdev->dev, "SPI_MST region map failed\n");
 		return PTR_ERR(dwsmscc->spi_mst);
 	}

 	dwsmscc->syscon = syscon_regmap_lookup_by_compatible(cpu_syscon);
 	if (IS_ERR(dwsmscc->syscon))
 		return PTR_ERR(dwsmscc->syscon);

 	/* Deassert all CS */
 	writel(0, dwsmscc->spi_mst + MSCC_SPI_MST_SW_MODE);

 	/* Select the owner of the SI interface */
 	regmap_update_bits(dwsmscc->syscon, MSCC_CPU_SYSTEM_CTRL_GENERAL_CTRL,
 			   MSCC_IF_SI_OWNER_MASK << if_si_owner_offset,
 			   MSCC_IF_SI_OWNER_SIMC << if_si_owner_offset);

 	dwsmmio->dws.set_cs = dw_spi_mscc_set_cs;
 	dwsmmio->priv = dwsmscc;

 	return 0;
 }

 static int dw_spi_mscc_ocelot_init(struct platform_device *pdev,
 				   struct dw_spi_mmio *dwsmmio)
 {
 	return dw_spi_mscc_init(pdev, dwsmmio, "mscc,ocelot-cpu-syscon",
 				OCELOT_IF_SI_OWNER_OFFSET);
 }

 static int dw_spi_mscc_jaguar2_init(struct platform_device *pdev,
 				    struct dw_spi_mmio *dwsmmio)
 {
 	return dw_spi_mscc_init(pdev, dwsmmio, "mscc,jaguar2-cpu-syscon",
 				JAGUAR2_IF_SI_OWNER_OFFSET);
 }

 /*
  * The Designware SPI controller (referred to as master in the
  * documentation) automatically deasserts chip select when the tx fifo
  * is empty. The chip selects then needs to be driven by a CS override
  * register. enable is an active low signal.
  */
 static void dw_spi_sparx5_set_cs(struct spi_device *spi, bool enable)
 {
 	struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
 	struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
 	struct dw_spi_mscc *dwsmscc = dwsmmio->priv;
 	u8 cs = spi_get_chipselect(spi, 0);

 	if (!enable) {
 		/* CS override drive enable */
 		regmap_write(dwsmscc->syscon, SPARX5_FORCE_ENA, 1);
 		/* Now set CSx enabled */
 		regmap_write(dwsmscc->syscon, SPARX5_FORCE_VAL, ~BIT(cs));
 		/* Allow settle */
 		usleep_range(1, 5);
 	} else {
 		/* CS value */
 		regmap_write(dwsmscc->syscon, SPARX5_FORCE_VAL, ~0);
 		/* Allow settle */
 		usleep_range(1, 5);
 		/* CS override drive disable */
 		regmap_write(dwsmscc->syscon, SPARX5_FORCE_ENA, 0);
 	}

 	dw_spi_set_cs(spi, enable);
 }

 static int dw_spi_mscc_sparx5_init(struct platform_device *pdev,
 				   struct dw_spi_mmio *dwsmmio)
 {
 	const char *syscon_name = "microchip,sparx5-cpu-syscon";
 	struct device *dev = &pdev->dev;
 	struct dw_spi_mscc *dwsmscc;

 	if (!IS_ENABLED(CONFIG_SPI_MUX)) {
 		dev_err(dev, "This driver needs CONFIG_SPI_MUX\n");
 		return -EOPNOTSUPP;
 	}

 	dwsmscc = devm_kzalloc(dev, sizeof(*dwsmscc), GFP_KERNEL);
 	if (!dwsmscc)
 		return -ENOMEM;

 	dwsmscc->syscon =
 		syscon_regmap_lookup_by_compatible(syscon_name);
 	if (IS_ERR(dwsmscc->syscon)) {
 		dev_err(dev, "No syscon map %s\n", syscon_name);
 		return PTR_ERR(dwsmscc->syscon);
 	}

 	dwsmmio->dws.set_cs = dw_spi_sparx5_set_cs;
 	dwsmmio->priv = dwsmscc;

 	return 0;
 }

 static int dw_spi_alpine_init(struct platform_device *pdev,
 			      struct dw_spi_mmio *dwsmmio)
 {
 	dwsmmio->dws.caps = DW_SPI_CAP_CS_OVERRIDE;

 	return 0;
 }

 static int dw_spi_pssi_init(struct platform_device *pdev,
 			    struct dw_spi_mmio *dwsmmio)
 {
 	dw_spi_dma_setup_generic(&dwsmmio->dws);

 	return 0;
 }

 static int dw_spi_hssi_init(struct platform_device *pdev,
 			    struct dw_spi_mmio *dwsmmio)
 {
 	dwsmmio->dws.ip = DW_HSSI_ID;

 	dw_spi_dma_setup_generic(&dwsmmio->dws);

 	return 0;
 }

 static int dw_spi_intel_init(struct platform_device *pdev,
 			     struct dw_spi_mmio *dwsmmio)
 {
 	dwsmmio->dws.ip = DW_HSSI_ID;

 	return 0;
 }

 /*
  * DMA-based mem ops are not configured for this device and are not tested.
  */
 static int dw_spi_mountevans_imc_init(struct platform_device *pdev,
 				      struct dw_spi_mmio *dwsmmio)
 {
 	/*
 	 * The Intel Mount Evans SoC's Integrated Management Complex DW
 	 * apb_ssi_v4.02a controller has an errata where a full TX FIFO can
 	 * result in data corruption. The suggested workaround is to never
 	 * completely fill the FIFO. The TX FIFO has a size of 32 so the
 	 * fifo_len is set to 31.
 	 */
 	dwsmmio->dws.fifo_len = 31;

 	return 0;
 }

 static int dw_spi_canaan_k210_init(struct platform_device *pdev,
 				   struct dw_spi_mmio *dwsmmio)
 {
 	/*
 	 * The Canaan Kendryte K210 SoC DW apb_ssi v4 spi controller is
 	 * documented to have a 32 word deep TX and RX FIFO, which
 	 * spi_hw_init() detects. However, when the RX FIFO is filled up to
 	 * 32 entries (RXFLR = 32), an RX FIFO overrun error occurs. Avoid this
 	 * problem by force setting fifo_len to 31.
 	 */
 	dwsmmio->dws.fifo_len = 31;

 	return 0;
 }

 static void dw_spi_elba_override_cs(struct regmap *syscon, int cs, int enable)
 {
 	regmap_update_bits(syscon, ELBA_SPICS_REG, ELBA_SPICS_MASK(cs),
 			   ELBA_SPICS_SET(cs, enable));
 }

 static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
 {
 	struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
 	struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
 	struct regmap *syscon = dwsmmio->priv;
 	u8 cs;

 	cs = spi_get_chipselect(spi, 0);
 	if (cs < 2)
 		dw_spi_elba_override_cs(syscon, spi_get_chipselect(spi, 0), enable);

 	/*
 	 * The DW SPI controller needs a native CS bit selected to start
 	 * the serial engine.
 	 */
 	spi_set_chipselect(spi, 0, 0);
 	dw_spi_set_cs(spi, enable);
 	spi_set_chipselect(spi, 0, cs);
 }

 static int dw_spi_elba_init(struct platform_device *pdev,
 			    struct dw_spi_mmio *dwsmmio)
 {
 	struct regmap *syscon;

 	syscon = syscon_regmap_lookup_by_phandle(dev_of_node(&pdev->dev),
 						 "amd,pensando-elba-syscon");
 	if (IS_ERR(syscon))
 		return dev_err_probe(&pdev->dev, PTR_ERR(syscon),
 				     "syscon regmap lookup failed\n");

 	dwsmmio->priv = syscon;
 	dwsmmio->dws.set_cs = dw_spi_elba_set_cs;

 	return 0;
 }

 static int dw_spi_mmio_probe(struct platform_device *pdev)
 {
 	int (*init_func)(struct platform_device *pdev,
 			 struct dw_spi_mmio *dwsmmio);
 	struct dw_spi_mmio *dwsmmio;
 	struct resource *mem;
 	struct dw_spi *dws;
 	int ret;
 	int num_cs;

 	dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
 			GFP_KERNEL);
 	if (!dwsmmio)
 		return -ENOMEM;

 	dws = &dwsmmio->dws;

 	/* Get basic io resource and map it */
 	dws->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
 	if (IS_ERR(dws->regs))
 		return PTR_ERR(dws->regs);

 	dws->paddr = mem->start;

 	dws->irq = platform_get_irq(pdev, 0);
 	if (dws->irq < 0)
 		return dws->irq; /* -ENXIO */

 	dwsmmio->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(dwsmmio->clk))
 		return PTR_ERR(dwsmmio->clk);
 	ret = clk_prepare_enable(dwsmmio->clk);
 	if (ret)
 		return ret;

 	/* Optional clock needed to access the registers */
 	dwsmmio->pclk = devm_clk_get_optional(&pdev->dev, "pclk");
 	if (IS_ERR(dwsmmio->pclk)) {
 		ret = PTR_ERR(dwsmmio->pclk);
 		goto out_clk;
 	}
 	ret = clk_prepare_enable(dwsmmio->pclk);
 	if (ret)
 		goto out_clk;

 	/* find an optional reset controller */
 	dwsmmio->rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, "spi");
 	if (IS_ERR(dwsmmio->rstc)) {
 		ret = PTR_ERR(dwsmmio->rstc);
 		goto out_clk;
 	}
 	reset_control_deassert(dwsmmio->rstc);

 	dws->bus_num = pdev->id;

 	dws->max_freq = clk_get_rate(dwsmmio->clk);

 	if (device_property_read_u32(&pdev->dev, "reg-io-width",
 				     &dws->reg_io_width))
 		dws->reg_io_width = 4;

 	num_cs = 4;

 	device_property_read_u32(&pdev->dev, "num-cs", &num_cs);

 	dws->num_cs = num_cs;

 	init_func = device_get_match_data(&pdev->dev);
 	if (init_func) {
 		ret = init_func(pdev, dwsmmio);
 		if (ret)
 			goto out;
 	}

 	pm_runtime_enable(&pdev->dev);

 	ret = dw_spi_add_host(&pdev->dev, dws);
 	if (ret)
 		goto out;

 	platform_set_drvdata(pdev, dwsmmio);
 	return 0;

 out:
 	pm_runtime_disable(&pdev->dev);
 	clk_disable_unprepare(dwsmmio->pclk);
 out_clk:
 	clk_disable_unprepare(dwsmmio->clk);
 	reset_control_assert(dwsmmio->rstc);

 	return ret;
 }

 static void dw_spi_mmio_remove(struct platform_device *pdev)
 {
 	struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);

 	dw_spi_remove_host(&dwsmmio->dws);
 	pm_runtime_disable(&pdev->dev);
 	clk_disable_unprepare(dwsmmio->pclk);
 	clk_disable_unprepare(dwsmmio->clk);
 	reset_control_assert(dwsmmio->rstc);
 }

 static const struct of_device_id dw_spi_mmio_of_match[] = {
 	{ .compatible = "snps,dw-apb-ssi", .data = dw_spi_pssi_init},
 	{ .compatible = "mscc,ocelot-spi", .data = dw_spi_mscc_ocelot_init},
 	{ .compatible = "mscc,jaguar2-spi", .data = dw_spi_mscc_jaguar2_init},
 	{ .compatible = "amazon,alpine-dw-apb-ssi", .data = dw_spi_alpine_init},
 	{ .compatible = "renesas,rzn1-spi", .data = dw_spi_pssi_init},
 	{ .compatible = "snps,dwc-ssi-1.01a", .data = dw_spi_hssi_init},
 	{ .compatible = "intel,keembay-ssi", .data = dw_spi_intel_init},
 	{ .compatible = "intel,thunderbay-ssi", .data = dw_spi_intel_init},
 	{
 		.compatible = "intel,mountevans-imc-ssi",
 		.data = dw_spi_mountevans_imc_init,
 	},
 	{ .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
 	{ .compatible = "canaan,k210-spi", dw_spi_canaan_k210_init},
 	{ .compatible = "amd,pensando-elba-spi", .data = dw_spi_elba_init},
 	{ /* end of table */}
 };
 MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);

 #ifdef CONFIG_ACPI
 static const struct acpi_device_id dw_spi_mmio_acpi_match[] = {
 	{"HISI0173", (kernel_ulong_t)dw_spi_pssi_init},
 	{},
 };
 MODULE_DEVICE_TABLE(acpi, dw_spi_mmio_acpi_match);
 #endif

 static struct platform_driver dw_spi_mmio_driver = {
 	.probe		= dw_spi_mmio_probe,
 	.remove_new	= dw_spi_mmio_remove,
 	.driver		= {
 		.name	= DRIVER_NAME,
 		.of_match_table = dw_spi_mmio_of_match,
 		.acpi_match_table = ACPI_PTR(dw_spi_mmio_acpi_match),
 	},
 };
 module_platform_driver(dw_spi_mmio_driver);

 MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
 MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
 MODULE_LICENSE("GPL v2");
 MODULE_IMPORT_NS(SPI_DW_CORE);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Memory-mapped interface driver for DW SPI Core
	*
	* Copyright (c) 2010, Octasic semiconductor.
	*/

	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/platform_device.h>
	#include <linux/pm_runtime.h>
	#include <linux/slab.h>
	#include <linux/spi/spi.h>
	#include <linux/scatterlist.h>
	#include <linux/mfd/syscon.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_platform.h>
	#include <linux/acpi.h>
	#include <linux/property.h>
	#include <linux/regmap.h>
	#include <linux/reset.h>

	#include "spi-dw.h"

	#define DRIVER_NAME "dw_spi_mmio"

	struct dw_spi_mmio {
	struct dw_spi dws;
	struct clk *clk;
	struct clk *pclk;
	void *priv;
	struct reset_control *rstc;
	};

	#define MSCC_CPU_SYSTEM_CTRL_GENERAL_CTRL 0x24
	#define OCELOT_IF_SI_OWNER_OFFSET 4
	#define JAGUAR2_IF_SI_OWNER_OFFSET 6
	#define MSCC_IF_SI_OWNER_MASK GENMASK(1, 0)
	#define MSCC_IF_SI_OWNER_SISL 0
	#define MSCC_IF_SI_OWNER_SIBM 1
	#define MSCC_IF_SI_OWNER_SIMC 2

	#define MSCC_SPI_MST_SW_MODE 0x14
	#define MSCC_SPI_MST_SW_MODE_SW_PIN_CTRL_MODE BIT(13)
	#define MSCC_SPI_MST_SW_MODE_SW_SPI_CS(x) (x << 5)

	#define SPARX5_FORCE_ENA 0xa4
	#define SPARX5_FORCE_VAL 0xa8

	struct dw_spi_mscc {
	struct regmap *syscon;
	void __iomem spi_mst; / Not sparx5 */
	};

	/*
	* Elba SoC does not use ssi, pin override is used for cs 0,1 and
	* gpios for cs 2,3 as defined in the device tree.
	*
	* cs: \| 1 0
	* bit: \|---3-------2-------1-------0
	* \| cs1 cs1_ovr cs0 cs0_ovr
	*/
	#define ELBA_SPICS_REG 0x2468
	#define ELBA_SPICS_OFFSET(cs) ((cs) << 1)
	#define ELBA_SPICS_MASK(cs) (GENMASK(1, 0) << ELBA_SPICS_OFFSET(cs))
	#define ELBA_SPICS_SET(cs, val) \
	((((val) << 1) \| BIT(0)) << ELBA_SPICS_OFFSET(cs))

	/*
	* The Designware SPI controller (referred to as master in the documentation)
	* automatically deasserts chip select when the tx fifo is empty. The chip
	* selects then needs to be either driven as GPIOs or, for the first 4 using
	* the SPI boot controller registers. the final chip select is an OR gate
	* between the Designware SPI controller and the SPI boot controller.
	*/
	static void dw_spi_mscc_set_cs(struct spi_device *spi, bool enable)
	{
	struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
	struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
	struct dw_spi_mscc *dwsmscc = dwsmmio->priv;
	u32 cs = spi_get_chipselect(spi, 0);

	if (cs < 4) {
	u32 sw_mode = MSCC_SPI_MST_SW_MODE_SW_PIN_CTRL_MODE;

	if (!enable)
	sw_mode \|= MSCC_SPI_MST_SW_MODE_SW_SPI_CS(BIT(cs));

	writel(sw_mode, dwsmscc->spi_mst + MSCC_SPI_MST_SW_MODE);
	}

	dw_spi_set_cs(spi, enable);
	}

	static int dw_spi_mscc_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio,
	const char *cpu_syscon, u32 if_si_owner_offset)
	{
	struct dw_spi_mscc *dwsmscc;

	dwsmscc = devm_kzalloc(&pdev->dev, sizeof(*dwsmscc), GFP_KERNEL);
	if (!dwsmscc)
	return -ENOMEM;

	dwsmscc->spi_mst = devm_platform_ioremap_resource(pdev, 1);
	if (IS_ERR(dwsmscc->spi_mst)) {
	dev_err(&pdev->dev, "SPI_MST region map failed\n");
	return PTR_ERR(dwsmscc->spi_mst);
	}

	dwsmscc->syscon = syscon_regmap_lookup_by_compatible(cpu_syscon);
	if (IS_ERR(dwsmscc->syscon))
	return PTR_ERR(dwsmscc->syscon);

	/* Deassert all CS */
	writel(0, dwsmscc->spi_mst + MSCC_SPI_MST_SW_MODE);

	/* Select the owner of the SI interface */
	regmap_update_bits(dwsmscc->syscon, MSCC_CPU_SYSTEM_CTRL_GENERAL_CTRL,
	MSCC_IF_SI_OWNER_MASK << if_si_owner_offset,
	MSCC_IF_SI_OWNER_SIMC << if_si_owner_offset);

	dwsmmio->dws.set_cs = dw_spi_mscc_set_cs;
	dwsmmio->priv = dwsmscc;

	return 0;
	}

	static int dw_spi_mscc_ocelot_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio)
	{
	return dw_spi_mscc_init(pdev, dwsmmio, "mscc,ocelot-cpu-syscon",
	OCELOT_IF_SI_OWNER_OFFSET);
	}

	static int dw_spi_mscc_jaguar2_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio)
	{
	return dw_spi_mscc_init(pdev, dwsmmio, "mscc,jaguar2-cpu-syscon",
	JAGUAR2_IF_SI_OWNER_OFFSET);
	}

	/*
	* The Designware SPI controller (referred to as master in the
	* documentation) automatically deasserts chip select when the tx fifo
	* is empty. The chip selects then needs to be driven by a CS override
	* register. enable is an active low signal.
	*/
	static void dw_spi_sparx5_set_cs(struct spi_device *spi, bool enable)
	{
	struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
	struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
	struct dw_spi_mscc *dwsmscc = dwsmmio->priv;
	u8 cs = spi_get_chipselect(spi, 0);

	if (!enable) {
	/* CS override drive enable */
	regmap_write(dwsmscc->syscon, SPARX5_FORCE_ENA, 1);
	/* Now set CSx enabled */
	regmap_write(dwsmscc->syscon, SPARX5_FORCE_VAL, ~BIT(cs));
	/* Allow settle */
	usleep_range(1, 5);
	} else {
	/* CS value */
	regmap_write(dwsmscc->syscon, SPARX5_FORCE_VAL, ~0);
	/* Allow settle */
	usleep_range(1, 5);
	/* CS override drive disable */
	regmap_write(dwsmscc->syscon, SPARX5_FORCE_ENA, 0);
	}

	dw_spi_set_cs(spi, enable);
	}

	static int dw_spi_mscc_sparx5_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio)
	{
	const char *syscon_name = "microchip,sparx5-cpu-syscon";
	struct device *dev = &pdev->dev;
	struct dw_spi_mscc *dwsmscc;

	if (!IS_ENABLED(CONFIG_SPI_MUX)) {
	dev_err(dev, "This driver needs CONFIG_SPI_MUX\n");
	return -EOPNOTSUPP;
	}

	dwsmscc = devm_kzalloc(dev, sizeof(*dwsmscc), GFP_KERNEL);
	if (!dwsmscc)
	return -ENOMEM;

	dwsmscc->syscon =
	syscon_regmap_lookup_by_compatible(syscon_name);
	if (IS_ERR(dwsmscc->syscon)) {
	dev_err(dev, "No syscon map %s\n", syscon_name);
	return PTR_ERR(dwsmscc->syscon);
	}

	dwsmmio->dws.set_cs = dw_spi_sparx5_set_cs;
	dwsmmio->priv = dwsmscc;

	return 0;
	}

	static int dw_spi_alpine_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio)
	{
	dwsmmio->dws.caps = DW_SPI_CAP_CS_OVERRIDE;

	return 0;
	}

	static int dw_spi_pssi_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio)
	{
	dw_spi_dma_setup_generic(&dwsmmio->dws);

	return 0;
	}

	static int dw_spi_hssi_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio)
	{
	dwsmmio->dws.ip = DW_HSSI_ID;

	dw_spi_dma_setup_generic(&dwsmmio->dws);

	return 0;
	}

	static int dw_spi_intel_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio)
	{
	dwsmmio->dws.ip = DW_HSSI_ID;

	return 0;
	}

	/*
	* DMA-based mem ops are not configured for this device and are not tested.
	*/
	static int dw_spi_mountevans_imc_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio)
	{
	/*
	* The Intel Mount Evans SoC's Integrated Management Complex DW
	* apb_ssi_v4.02a controller has an errata where a full TX FIFO can
	* result in data corruption. The suggested workaround is to never
	* completely fill the FIFO. The TX FIFO has a size of 32 so the
	* fifo_len is set to 31.
	*/
	dwsmmio->dws.fifo_len = 31;

	return 0;
	}

	static int dw_spi_canaan_k210_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio)
	{
	/*
	* The Canaan Kendryte K210 SoC DW apb_ssi v4 spi controller is
	* documented to have a 32 word deep TX and RX FIFO, which
	* spi_hw_init() detects. However, when the RX FIFO is filled up to
	* 32 entries (RXFLR = 32), an RX FIFO overrun error occurs. Avoid this
	* problem by force setting fifo_len to 31.
	*/
	dwsmmio->dws.fifo_len = 31;

	return 0;
	}

	static void dw_spi_elba_override_cs(struct regmap *syscon, int cs, int enable)
	{
	regmap_update_bits(syscon, ELBA_SPICS_REG, ELBA_SPICS_MASK(cs),
	ELBA_SPICS_SET(cs, enable));
	}

	static void dw_spi_elba_set_cs(struct spi_device *spi, bool enable)
	{
	struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
	struct dw_spi_mmio *dwsmmio = container_of(dws, struct dw_spi_mmio, dws);
	struct regmap *syscon = dwsmmio->priv;
	u8 cs;

	cs = spi_get_chipselect(spi, 0);
	if (cs < 2)
	dw_spi_elba_override_cs(syscon, spi_get_chipselect(spi, 0), enable);

	/*
	* The DW SPI controller needs a native CS bit selected to start
	* the serial engine.
	*/
	spi_set_chipselect(spi, 0, 0);
	dw_spi_set_cs(spi, enable);
	spi_set_chipselect(spi, 0, cs);
	}

	static int dw_spi_elba_init(struct platform_device *pdev,
	struct dw_spi_mmio *dwsmmio)
	{
	struct regmap *syscon;

	syscon = syscon_regmap_lookup_by_phandle(dev_of_node(&pdev->dev),
	"amd,pensando-elba-syscon");
	if (IS_ERR(syscon))
	return dev_err_probe(&pdev->dev, PTR_ERR(syscon),
	"syscon regmap lookup failed\n");

	dwsmmio->priv = syscon;
	dwsmmio->dws.set_cs = dw_spi_elba_set_cs;

	return 0;
	}

	static int dw_spi_mmio_probe(struct platform_device *pdev)
	{
	int (init_func)(struct platform_device pdev,
	struct dw_spi_mmio *dwsmmio);
	struct dw_spi_mmio *dwsmmio;
	struct resource *mem;
	struct dw_spi *dws;
	int ret;
	int num_cs;

	dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
	GFP_KERNEL);
	if (!dwsmmio)
	return -ENOMEM;

	dws = &dwsmmio->dws;

	/* Get basic io resource and map it */
	dws->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
	if (IS_ERR(dws->regs))
	return PTR_ERR(dws->regs);

	dws->paddr = mem->start;

	dws->irq = platform_get_irq(pdev, 0);
	if (dws->irq < 0)
	return dws->irq; /* -ENXIO */

	dwsmmio->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(dwsmmio->clk))
	return PTR_ERR(dwsmmio->clk);
	ret = clk_prepare_enable(dwsmmio->clk);
	if (ret)
	return ret;

	/* Optional clock needed to access the registers */
	dwsmmio->pclk = devm_clk_get_optional(&pdev->dev, "pclk");
	if (IS_ERR(dwsmmio->pclk)) {
	ret = PTR_ERR(dwsmmio->pclk);
	goto out_clk;
	}
	ret = clk_prepare_enable(dwsmmio->pclk);
	if (ret)
	goto out_clk;

	/* find an optional reset controller */
	dwsmmio->rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, "spi");
	if (IS_ERR(dwsmmio->rstc)) {
	ret = PTR_ERR(dwsmmio->rstc);
	goto out_clk;
	}
	reset_control_deassert(dwsmmio->rstc);

	dws->bus_num = pdev->id;

	dws->max_freq = clk_get_rate(dwsmmio->clk);

	if (device_property_read_u32(&pdev->dev, "reg-io-width",
	&dws->reg_io_width))
	dws->reg_io_width = 4;

	num_cs = 4;

	device_property_read_u32(&pdev->dev, "num-cs", &num_cs);

	dws->num_cs = num_cs;

	init_func = device_get_match_data(&pdev->dev);
	if (init_func) {
	ret = init_func(pdev, dwsmmio);
	if (ret)
	goto out;
	}

	pm_runtime_enable(&pdev->dev);

	ret = dw_spi_add_host(&pdev->dev, dws);
	if (ret)
	goto out;

	platform_set_drvdata(pdev, dwsmmio);
	return 0;

	out:
	pm_runtime_disable(&pdev->dev);
	clk_disable_unprepare(dwsmmio->pclk);
	out_clk:
	clk_disable_unprepare(dwsmmio->clk);
	reset_control_assert(dwsmmio->rstc);

	return ret;
	}

	static void dw_spi_mmio_remove(struct platform_device *pdev)
	{
	struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);

	dw_spi_remove_host(&dwsmmio->dws);
	pm_runtime_disable(&pdev->dev);
	clk_disable_unprepare(dwsmmio->pclk);
	clk_disable_unprepare(dwsmmio->clk);
	reset_control_assert(dwsmmio->rstc);
	}

	static const struct of_device_id dw_spi_mmio_of_match[] = {
	{ .compatible = "snps,dw-apb-ssi", .data = dw_spi_pssi_init},
	{ .compatible = "mscc,ocelot-spi", .data = dw_spi_mscc_ocelot_init},
	{ .compatible = "mscc,jaguar2-spi", .data = dw_spi_mscc_jaguar2_init},
	{ .compatible = "amazon,alpine-dw-apb-ssi", .data = dw_spi_alpine_init},
	{ .compatible = "renesas,rzn1-spi", .data = dw_spi_pssi_init},
	{ .compatible = "snps,dwc-ssi-1.01a", .data = dw_spi_hssi_init},
	{ .compatible = "intel,keembay-ssi", .data = dw_spi_intel_init},
	{ .compatible = "intel,thunderbay-ssi", .data = dw_spi_intel_init},
	{
	.compatible = "intel,mountevans-imc-ssi",
	.data = dw_spi_mountevans_imc_init,
	},
	{ .compatible = "microchip,sparx5-spi", dw_spi_mscc_sparx5_init},
	{ .compatible = "canaan,k210-spi", dw_spi_canaan_k210_init},
	{ .compatible = "amd,pensando-elba-spi", .data = dw_spi_elba_init},
	{ /* end of table */}
	};
	MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);

	#ifdef CONFIG_ACPI
	static const struct acpi_device_id dw_spi_mmio_acpi_match[] = {
	{"HISI0173", (kernel_ulong_t)dw_spi_pssi_init},
	{},
	};
	MODULE_DEVICE_TABLE(acpi, dw_spi_mmio_acpi_match);
	#endif

	static struct platform_driver dw_spi_mmio_driver = {
	.probe = dw_spi_mmio_probe,
	.remove_new = dw_spi_mmio_remove,
	.driver = {
	.name = DRIVER_NAME,
	.of_match_table = dw_spi_mmio_of_match,
	.acpi_match_table = ACPI_PTR(dw_spi_mmio_acpi_match),
	},
	};
	module_platform_driver(dw_spi_mmio_driver);

	MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
	MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
	MODULE_LICENSE("GPL v2");
	MODULE_IMPORT_NS(SPI_DW_CORE);