Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 761 insertions, 0 deletions

diff --git a/drivers/spi/spi-ep93xx.c b/drivers/spi/spi-ep93xx.c
new file mode 100644
index 0000000000..a1d60e51c0
--- /dev/null
+++ b/drivers/spi/spi-ep93xx.c
@@ -0,0 +1,761 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Cirrus Logic EP93xx SPI controller.
+ *
+ * Copyright (C) 2010-2011 Mika Westerberg
+ *
+ * Explicit FIFO handling code was inspired by amba-pl022 driver.
+ *
+ * Chip select support using other than built-in GPIOs by H. Hartley Sweeten.
+ *
+ * For more information about the SPI controller see documentation on Cirrus
+ * Logic web site:
+ *     https://www.cirrus.com/en/pubs/manual/EP93xx_Users_Guide_UM1.pdf
+ */
+
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dmaengine.h>
+#include <linux/bitops.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/scatterlist.h>
+#include <linux/spi/spi.h>
+
+#include <linux/platform_data/dma-ep93xx.h>
+#include <linux/platform_data/spi-ep93xx.h>
+
+#define SSPCR0			0x0000
+#define SSPCR0_SPO		BIT(6)
+#define SSPCR0_SPH		BIT(7)
+#define SSPCR0_SCR_SHIFT	8
+
+#define SSPCR1			0x0004
+#define SSPCR1_RIE		BIT(0)
+#define SSPCR1_TIE		BIT(1)
+#define SSPCR1_RORIE		BIT(2)
+#define SSPCR1_LBM		BIT(3)
+#define SSPCR1_SSE		BIT(4)
+#define SSPCR1_MS		BIT(5)
+#define SSPCR1_SOD		BIT(6)
+
+#define SSPDR			0x0008
+
+#define SSPSR			0x000c
+#define SSPSR_TFE		BIT(0)
+#define SSPSR_TNF		BIT(1)
+#define SSPSR_RNE		BIT(2)
+#define SSPSR_RFF		BIT(3)
+#define SSPSR_BSY		BIT(4)
+#define SSPCPSR			0x0010
+
+#define SSPIIR			0x0014
+#define SSPIIR_RIS		BIT(0)
+#define SSPIIR_TIS		BIT(1)
+#define SSPIIR_RORIS		BIT(2)
+#define SSPICR			SSPIIR
+
+/* timeout in milliseconds */
+#define SPI_TIMEOUT		5
+/* maximum depth of RX/TX FIFO */
+#define SPI_FIFO_SIZE		8
+
+/**
+ * struct ep93xx_spi - EP93xx SPI controller structure
+ * @clk: clock for the controller
+ * @mmio: pointer to ioremap()'d registers
+ * @sspdr_phys: physical address of the SSPDR register
+ * @tx: current byte in transfer to transmit
+ * @rx: current byte in transfer to receive
+ * @fifo_level: how full is FIFO (%0..%SPI_FIFO_SIZE - %1). Receiving one
+ *              frame decreases this level and sending one frame increases it.
+ * @dma_rx: RX DMA channel
+ * @dma_tx: TX DMA channel
+ * @dma_rx_data: RX parameters passed to the DMA engine
+ * @dma_tx_data: TX parameters passed to the DMA engine
+ * @rx_sgt: sg table for RX transfers
+ * @tx_sgt: sg table for TX transfers
+ * @zeropage: dummy page used as RX buffer when only TX buffer is passed in by
+ *            the client
+ */
+struct ep93xx_spi {
+	struct clk			*clk;
+	void __iomem			*mmio;
+	unsigned long			sspdr_phys;
+	size_t				tx;
+	size_t				rx;
+	size_t				fifo_level;
+	struct dma_chan			*dma_rx;
+	struct dma_chan			*dma_tx;
+	struct ep93xx_dma_data		dma_rx_data;
+	struct ep93xx_dma_data		dma_tx_data;
+	struct sg_table			rx_sgt;
+	struct sg_table			tx_sgt;
+	void				*zeropage;
+};
+
+/* converts bits per word to CR0.DSS value */
+#define bits_per_word_to_dss(bpw)	((bpw) - 1)
+
+/**
+ * ep93xx_spi_calc_divisors() - calculates SPI clock divisors
+ * @host: SPI host
+ * @rate: desired SPI output clock rate
+ * @div_cpsr: pointer to return the cpsr (pre-scaler) divider
+ * @div_scr: pointer to return the scr divider
+ */
+static int ep93xx_spi_calc_divisors(struct spi_controller *host,
+				    u32 rate, u8 *div_cpsr, u8 *div_scr)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	unsigned long spi_clk_rate = clk_get_rate(espi->clk);
+	int cpsr, scr;
+
+	/*
+	 * Make sure that max value is between values supported by the
+	 * controller.
+	 */
+	rate = clamp(rate, host->min_speed_hz, host->max_speed_hz);
+
+	/*
+	 * Calculate divisors so that we can get speed according the
+	 * following formula:
+	 *	rate = spi_clock_rate / (cpsr * (1 + scr))
+	 *
+	 * cpsr must be even number and starts from 2, scr can be any number
+	 * between 0 and 255.
+	 */
+	for (cpsr = 2; cpsr <= 254; cpsr += 2) {
+		for (scr = 0; scr <= 255; scr++) {
+			if ((spi_clk_rate / (cpsr * (scr + 1))) <= rate) {
+				*div_scr = (u8)scr;
+				*div_cpsr = (u8)cpsr;
+				return 0;
+			}
+		}
+	}
+
+	return -EINVAL;
+}
+
+static int ep93xx_spi_chip_setup(struct spi_controller *host,
+				 struct spi_device *spi,
+				 struct spi_transfer *xfer)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	u8 dss = bits_per_word_to_dss(xfer->bits_per_word);
+	u8 div_cpsr = 0;
+	u8 div_scr = 0;
+	u16 cr0;
+	int err;
+
+	err = ep93xx_spi_calc_divisors(host, xfer->speed_hz,
+				       &div_cpsr, &div_scr);
+	if (err)
+		return err;
+
+	cr0 = div_scr << SSPCR0_SCR_SHIFT;
+	if (spi->mode & SPI_CPOL)
+		cr0 |= SSPCR0_SPO;
+	if (spi->mode & SPI_CPHA)
+		cr0 |= SSPCR0_SPH;
+	cr0 |= dss;
+
+	dev_dbg(&host->dev, "setup: mode %d, cpsr %d, scr %d, dss %d\n",
+		spi->mode, div_cpsr, div_scr, dss);
+	dev_dbg(&host->dev, "setup: cr0 %#x\n", cr0);
+
+	writel(div_cpsr, espi->mmio + SSPCPSR);
+	writel(cr0, espi->mmio + SSPCR0);
+
+	return 0;
+}
+
+static void ep93xx_do_write(struct spi_controller *host)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	struct spi_transfer *xfer = host->cur_msg->state;
+	u32 val = 0;
+
+	if (xfer->bits_per_word > 8) {
+		if (xfer->tx_buf)
+			val = ((u16 *)xfer->tx_buf)[espi->tx];
+		espi->tx += 2;
+	} else {
+		if (xfer->tx_buf)
+			val = ((u8 *)xfer->tx_buf)[espi->tx];
+		espi->tx += 1;
+	}
+	writel(val, espi->mmio + SSPDR);
+}
+
+static void ep93xx_do_read(struct spi_controller *host)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	struct spi_transfer *xfer = host->cur_msg->state;
+	u32 val;
+
+	val = readl(espi->mmio + SSPDR);
+	if (xfer->bits_per_word > 8) {
+		if (xfer->rx_buf)
+			((u16 *)xfer->rx_buf)[espi->rx] = val;
+		espi->rx += 2;
+	} else {
+		if (xfer->rx_buf)
+			((u8 *)xfer->rx_buf)[espi->rx] = val;
+		espi->rx += 1;
+	}
+}
+
+/**
+ * ep93xx_spi_read_write() - perform next RX/TX transfer
+ * @host: SPI host
+ *
+ * This function transfers next bytes (or half-words) to/from RX/TX FIFOs. If
+ * called several times, the whole transfer will be completed. Returns
+ * %-EINPROGRESS when current transfer was not yet completed otherwise %0.
+ *
+ * When this function is finished, RX FIFO should be empty and TX FIFO should be
+ * full.
+ */
+static int ep93xx_spi_read_write(struct spi_controller *host)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	struct spi_transfer *xfer = host->cur_msg->state;
+
+	/* read as long as RX FIFO has frames in it */
+	while ((readl(espi->mmio + SSPSR) & SSPSR_RNE)) {
+		ep93xx_do_read(host);
+		espi->fifo_level--;
+	}
+
+	/* write as long as TX FIFO has room */
+	while (espi->fifo_level < SPI_FIFO_SIZE && espi->tx < xfer->len) {
+		ep93xx_do_write(host);
+		espi->fifo_level++;
+	}
+
+	if (espi->rx == xfer->len)
+		return 0;
+
+	return -EINPROGRESS;
+}
+
+static enum dma_transfer_direction
+ep93xx_dma_data_to_trans_dir(enum dma_data_direction dir)
+{
+	switch (dir) {
+	case DMA_TO_DEVICE:
+		return DMA_MEM_TO_DEV;
+	case DMA_FROM_DEVICE:
+		return DMA_DEV_TO_MEM;
+	default:
+		return DMA_TRANS_NONE;
+	}
+}
+
+/**
+ * ep93xx_spi_dma_prepare() - prepares a DMA transfer
+ * @host: SPI host
+ * @dir: DMA transfer direction
+ *
+ * Function configures the DMA, maps the buffer and prepares the DMA
+ * descriptor. Returns a valid DMA descriptor in case of success and ERR_PTR
+ * in case of failure.
+ */
+static struct dma_async_tx_descriptor *
+ep93xx_spi_dma_prepare(struct spi_controller *host,
+		       enum dma_data_direction dir)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	struct spi_transfer *xfer = host->cur_msg->state;
+	struct dma_async_tx_descriptor *txd;
+	enum dma_slave_buswidth buswidth;
+	struct dma_slave_config conf;
+	struct scatterlist *sg;
+	struct sg_table *sgt;
+	struct dma_chan *chan;
+	const void *buf, *pbuf;
+	size_t len = xfer->len;
+	int i, ret, nents;
+
+	if (xfer->bits_per_word > 8)
+		buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES;
+	else
+		buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
+
+	memset(&conf, 0, sizeof(conf));
+	conf.direction = ep93xx_dma_data_to_trans_dir(dir);
+
+	if (dir == DMA_FROM_DEVICE) {
+		chan = espi->dma_rx;
+		buf = xfer->rx_buf;
+		sgt = &espi->rx_sgt;
+
+		conf.src_addr = espi->sspdr_phys;
+		conf.src_addr_width = buswidth;
+	} else {
+		chan = espi->dma_tx;
+		buf = xfer->tx_buf;
+		sgt = &espi->tx_sgt;
+
+		conf.dst_addr = espi->sspdr_phys;
+		conf.dst_addr_width = buswidth;
+	}
+
+	ret = dmaengine_slave_config(chan, &conf);
+	if (ret)
+		return ERR_PTR(ret);
+
+	/*
+	 * We need to split the transfer into PAGE_SIZE'd chunks. This is
+	 * because we are using @espi->zeropage to provide a zero RX buffer
+	 * for the TX transfers and we have only allocated one page for that.
+	 *
+	 * For performance reasons we allocate a new sg_table only when
+	 * needed. Otherwise we will re-use the current one. Eventually the
+	 * last sg_table is released in ep93xx_spi_release_dma().
+	 */
+
+	nents = DIV_ROUND_UP(len, PAGE_SIZE);
+	if (nents != sgt->nents) {
+		sg_free_table(sgt);
+
+		ret = sg_alloc_table(sgt, nents, GFP_KERNEL);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	pbuf = buf;
+	for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+		size_t bytes = min_t(size_t, len, PAGE_SIZE);
+
+		if (buf) {
+			sg_set_page(sg, virt_to_page(pbuf), bytes,
+				    offset_in_page(pbuf));
+		} else {
+			sg_set_page(sg, virt_to_page(espi->zeropage),
+				    bytes, 0);
+		}
+
+		pbuf += bytes;
+		len -= bytes;
+	}
+
+	if (WARN_ON(len)) {
+		dev_warn(&host->dev, "len = %zu expected 0!\n", len);
+		return ERR_PTR(-EINVAL);
+	}
+
+	nents = dma_map_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
+	if (!nents)
+		return ERR_PTR(-ENOMEM);
+
+	txd = dmaengine_prep_slave_sg(chan, sgt->sgl, nents, conf.direction,
+				      DMA_CTRL_ACK);
+	if (!txd) {
+		dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
+		return ERR_PTR(-ENOMEM);
+	}
+	return txd;
+}
+
+/**
+ * ep93xx_spi_dma_finish() - finishes with a DMA transfer
+ * @host: SPI host
+ * @dir: DMA transfer direction
+ *
+ * Function finishes with the DMA transfer. After this, the DMA buffer is
+ * unmapped.
+ */
+static void ep93xx_spi_dma_finish(struct spi_controller *host,
+				  enum dma_data_direction dir)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	struct dma_chan *chan;
+	struct sg_table *sgt;
+
+	if (dir == DMA_FROM_DEVICE) {
+		chan = espi->dma_rx;
+		sgt = &espi->rx_sgt;
+	} else {
+		chan = espi->dma_tx;
+		sgt = &espi->tx_sgt;
+	}
+
+	dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir);
+}
+
+static void ep93xx_spi_dma_callback(void *callback_param)
+{
+	struct spi_controller *host = callback_param;
+
+	ep93xx_spi_dma_finish(host, DMA_TO_DEVICE);
+	ep93xx_spi_dma_finish(host, DMA_FROM_DEVICE);
+
+	spi_finalize_current_transfer(host);
+}
+
+static int ep93xx_spi_dma_transfer(struct spi_controller *host)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	struct dma_async_tx_descriptor *rxd, *txd;
+
+	rxd = ep93xx_spi_dma_prepare(host, DMA_FROM_DEVICE);
+	if (IS_ERR(rxd)) {
+		dev_err(&host->dev, "DMA RX failed: %ld\n", PTR_ERR(rxd));
+		return PTR_ERR(rxd);
+	}
+
+	txd = ep93xx_spi_dma_prepare(host, DMA_TO_DEVICE);
+	if (IS_ERR(txd)) {
+		ep93xx_spi_dma_finish(host, DMA_FROM_DEVICE);
+		dev_err(&host->dev, "DMA TX failed: %ld\n", PTR_ERR(txd));
+		return PTR_ERR(txd);
+	}
+
+	/* We are ready when RX is done */
+	rxd->callback = ep93xx_spi_dma_callback;
+	rxd->callback_param = host;
+
+	/* Now submit both descriptors and start DMA */
+	dmaengine_submit(rxd);
+	dmaengine_submit(txd);
+
+	dma_async_issue_pending(espi->dma_rx);
+	dma_async_issue_pending(espi->dma_tx);
+
+	/* signal that we need to wait for completion */
+	return 1;
+}
+
+static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id)
+{
+	struct spi_controller *host = dev_id;
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	u32 val;
+
+	/*
+	 * If we got ROR (receive overrun) interrupt we know that something is
+	 * wrong. Just abort the message.
+	 */
+	if (readl(espi->mmio + SSPIIR) & SSPIIR_RORIS) {
+		/* clear the overrun interrupt */
+		writel(0, espi->mmio + SSPICR);
+		dev_warn(&host->dev,
+			 "receive overrun, aborting the message\n");
+		host->cur_msg->status = -EIO;
+	} else {
+		/*
+		 * Interrupt is either RX (RIS) or TX (TIS). For both cases we
+		 * simply execute next data transfer.
+		 */
+		if (ep93xx_spi_read_write(host)) {
+			/*
+			 * In normal case, there still is some processing left
+			 * for current transfer. Let's wait for the next
+			 * interrupt then.
+			 */
+			return IRQ_HANDLED;
+		}
+	}
+
+	/*
+	 * Current transfer is finished, either with error or with success. In
+	 * any case we disable interrupts and notify the worker to handle
+	 * any post-processing of the message.
+	 */
+	val = readl(espi->mmio + SSPCR1);
+	val &= ~(SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE);
+	writel(val, espi->mmio + SSPCR1);
+
+	spi_finalize_current_transfer(host);
+
+	return IRQ_HANDLED;
+}
+
+static int ep93xx_spi_transfer_one(struct spi_controller *host,
+				   struct spi_device *spi,
+				   struct spi_transfer *xfer)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	u32 val;
+	int ret;
+
+	ret = ep93xx_spi_chip_setup(host, spi, xfer);
+	if (ret) {
+		dev_err(&host->dev, "failed to setup chip for transfer\n");
+		return ret;
+	}
+
+	host->cur_msg->state = xfer;
+	espi->rx = 0;
+	espi->tx = 0;
+
+	/*
+	 * There is no point of setting up DMA for the transfers which will
+	 * fit into the FIFO and can be transferred with a single interrupt.
+	 * So in these cases we will be using PIO and don't bother for DMA.
+	 */
+	if (espi->dma_rx && xfer->len > SPI_FIFO_SIZE)
+		return ep93xx_spi_dma_transfer(host);
+
+	/* Using PIO so prime the TX FIFO and enable interrupts */
+	ep93xx_spi_read_write(host);
+
+	val = readl(espi->mmio + SSPCR1);
+	val |= (SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE);
+	writel(val, espi->mmio + SSPCR1);
+
+	/* signal that we need to wait for completion */
+	return 1;
+}
+
+static int ep93xx_spi_prepare_message(struct spi_controller *host,
+				      struct spi_message *msg)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	unsigned long timeout;
+
+	/*
+	 * Just to be sure: flush any data from RX FIFO.
+	 */
+	timeout = jiffies + msecs_to_jiffies(SPI_TIMEOUT);
+	while (readl(espi->mmio + SSPSR) & SSPSR_RNE) {
+		if (time_after(jiffies, timeout)) {
+			dev_warn(&host->dev,
+				 "timeout while flushing RX FIFO\n");
+			return -ETIMEDOUT;
+		}
+		readl(espi->mmio + SSPDR);
+	}
+
+	/*
+	 * We explicitly handle FIFO level. This way we don't have to check TX
+	 * FIFO status using %SSPSR_TNF bit which may cause RX FIFO overruns.
+	 */
+	espi->fifo_level = 0;
+
+	return 0;
+}
+
+static int ep93xx_spi_prepare_hardware(struct spi_controller *host)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	u32 val;
+	int ret;
+
+	ret = clk_prepare_enable(espi->clk);
+	if (ret)
+		return ret;
+
+	val = readl(espi->mmio + SSPCR1);
+	val |= SSPCR1_SSE;
+	writel(val, espi->mmio + SSPCR1);
+
+	return 0;
+}
+
+static int ep93xx_spi_unprepare_hardware(struct spi_controller *host)
+{
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+	u32 val;
+
+	val = readl(espi->mmio + SSPCR1);
+	val &= ~SSPCR1_SSE;
+	writel(val, espi->mmio + SSPCR1);
+
+	clk_disable_unprepare(espi->clk);
+
+	return 0;
+}
+
+static bool ep93xx_spi_dma_filter(struct dma_chan *chan, void *filter_param)
+{
+	if (ep93xx_dma_chan_is_m2p(chan))
+		return false;
+
+	chan->private = filter_param;
+	return true;
+}
+
+static int ep93xx_spi_setup_dma(struct ep93xx_spi *espi)
+{
+	dma_cap_mask_t mask;
+	int ret;
+
+	espi->zeropage = (void *)get_zeroed_page(GFP_KERNEL);
+	if (!espi->zeropage)
+		return -ENOMEM;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	espi->dma_rx_data.port = EP93XX_DMA_SSP;
+	espi->dma_rx_data.direction = DMA_DEV_TO_MEM;
+	espi->dma_rx_data.name = "ep93xx-spi-rx";
+
+	espi->dma_rx = dma_request_channel(mask, ep93xx_spi_dma_filter,
+					   &espi->dma_rx_data);
+	if (!espi->dma_rx) {
+		ret = -ENODEV;
+		goto fail_free_page;
+	}
+
+	espi->dma_tx_data.port = EP93XX_DMA_SSP;
+	espi->dma_tx_data.direction = DMA_MEM_TO_DEV;
+	espi->dma_tx_data.name = "ep93xx-spi-tx";
+
+	espi->dma_tx = dma_request_channel(mask, ep93xx_spi_dma_filter,
+					   &espi->dma_tx_data);
+	if (!espi->dma_tx) {
+		ret = -ENODEV;
+		goto fail_release_rx;
+	}
+
+	return 0;
+
+fail_release_rx:
+	dma_release_channel(espi->dma_rx);
+	espi->dma_rx = NULL;
+fail_free_page:
+	free_page((unsigned long)espi->zeropage);
+
+	return ret;
+}
+
+static void ep93xx_spi_release_dma(struct ep93xx_spi *espi)
+{
+	if (espi->dma_rx) {
+		dma_release_channel(espi->dma_rx);
+		sg_free_table(&espi->rx_sgt);
+	}
+	if (espi->dma_tx) {
+		dma_release_channel(espi->dma_tx);
+		sg_free_table(&espi->tx_sgt);
+	}
+
+	if (espi->zeropage)
+		free_page((unsigned long)espi->zeropage);
+}
+
+static int ep93xx_spi_probe(struct platform_device *pdev)
+{
+	struct spi_controller *host;
+	struct ep93xx_spi_info *info;
+	struct ep93xx_spi *espi;
+	struct resource *res;
+	int irq;
+	int error;
+
+	info = dev_get_platdata(&pdev->dev);
+	if (!info) {
+		dev_err(&pdev->dev, "missing platform data\n");
+		return -EINVAL;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	host = spi_alloc_host(&pdev->dev, sizeof(*espi));
+	if (!host)
+		return -ENOMEM;
+
+	host->use_gpio_descriptors = true;
+	host->prepare_transfer_hardware = ep93xx_spi_prepare_hardware;
+	host->unprepare_transfer_hardware = ep93xx_spi_unprepare_hardware;
+	host->prepare_message = ep93xx_spi_prepare_message;
+	host->transfer_one = ep93xx_spi_transfer_one;
+	host->bus_num = pdev->id;
+	host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+	host->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16);
+	/*
+	 * The SPI core will count the number of GPIO descriptors to figure
+	 * out the number of chip selects available on the platform.
+	 */
+	host->num_chipselect = 0;
+
+	platform_set_drvdata(pdev, host);
+
+	espi = spi_controller_get_devdata(host);
+
+	espi->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(espi->clk)) {
+		dev_err(&pdev->dev, "unable to get spi clock\n");
+		error = PTR_ERR(espi->clk);
+		goto fail_release_host;
+	}
+
+	/*
+	 * Calculate maximum and minimum supported clock rates
+	 * for the controller.
+	 */
+	host->max_speed_hz = clk_get_rate(espi->clk) / 2;
+	host->min_speed_hz = clk_get_rate(espi->clk) / (254 * 256);
+
+	espi->mmio = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+	if (IS_ERR(espi->mmio)) {
+		error = PTR_ERR(espi->mmio);
+		goto fail_release_host;
+	}
+	espi->sspdr_phys = res->start + SSPDR;
+
+	error = devm_request_irq(&pdev->dev, irq, ep93xx_spi_interrupt,
+				0, "ep93xx-spi", host);
+	if (error) {
+		dev_err(&pdev->dev, "failed to request irq\n");
+		goto fail_release_host;
+	}
+
+	if (info->use_dma && ep93xx_spi_setup_dma(espi))
+		dev_warn(&pdev->dev, "DMA setup failed. Falling back to PIO\n");
+
+	/* make sure that the hardware is disabled */
+	writel(0, espi->mmio + SSPCR1);
+
+	error = devm_spi_register_controller(&pdev->dev, host);
+	if (error) {
+		dev_err(&pdev->dev, "failed to register SPI host\n");
+		goto fail_free_dma;
+	}
+
+	dev_info(&pdev->dev, "EP93xx SPI Controller at 0x%08lx irq %d\n",
+		 (unsigned long)res->start, irq);
+
+	return 0;
+
+fail_free_dma:
+	ep93xx_spi_release_dma(espi);
+fail_release_host:
+	spi_controller_put(host);
+
+	return error;
+}
+
+static void ep93xx_spi_remove(struct platform_device *pdev)
+{
+	struct spi_controller *host = platform_get_drvdata(pdev);
+	struct ep93xx_spi *espi = spi_controller_get_devdata(host);
+
+	ep93xx_spi_release_dma(espi);
+}
+
+static struct platform_driver ep93xx_spi_driver = {
+	.driver		= {
+		.name	= "ep93xx-spi",
+	},
+	.probe		= ep93xx_spi_probe,
+	.remove_new	= ep93xx_spi_remove,
+};
+module_platform_driver(ep93xx_spi_driver);
+
+MODULE_DESCRIPTION("EP93xx SPI Controller driver");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ep93xx-spi");