Initial import

1 files changed, 1540 insertions, 0 deletions

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
new file mode 100644
index 000000000..a2f40b1b2
--- /dev/null
+++ b/drivers/spi/spi-atmel.c
@@ -0,0 +1,1540 @@
+/*
+ * Driver for Atmel AT32 and AT91 SPI Controllers
+ *
+ * Copyright (C) 2006 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/spi/spi.h>
+#include <linux/slab.h>
+#include <linux/platform_data/atmel.h>
+#include <linux/platform_data/dma-atmel.h>
+#include <linux/of.h>
+
+#include <linux/io.h>
+#include <linux/gpio.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/pm_runtime.h>
+
+/* SPI register offsets */
+#define SPI_CR					0x0000
+#define SPI_MR					0x0004
+#define SPI_RDR					0x0008
+#define SPI_TDR					0x000c
+#define SPI_SR					0x0010
+#define SPI_IER					0x0014
+#define SPI_IDR					0x0018
+#define SPI_IMR					0x001c
+#define SPI_CSR0				0x0030
+#define SPI_CSR1				0x0034
+#define SPI_CSR2				0x0038
+#define SPI_CSR3				0x003c
+#define SPI_VERSION				0x00fc
+#define SPI_RPR					0x0100
+#define SPI_RCR					0x0104
+#define SPI_TPR					0x0108
+#define SPI_TCR					0x010c
+#define SPI_RNPR				0x0110
+#define SPI_RNCR				0x0114
+#define SPI_TNPR				0x0118
+#define SPI_TNCR				0x011c
+#define SPI_PTCR				0x0120
+#define SPI_PTSR				0x0124
+
+/* Bitfields in CR */
+#define SPI_SPIEN_OFFSET			0
+#define SPI_SPIEN_SIZE				1
+#define SPI_SPIDIS_OFFSET			1
+#define SPI_SPIDIS_SIZE				1
+#define SPI_SWRST_OFFSET			7
+#define SPI_SWRST_SIZE				1
+#define SPI_LASTXFER_OFFSET			24
+#define SPI_LASTXFER_SIZE			1
+
+/* Bitfields in MR */
+#define SPI_MSTR_OFFSET				0
+#define SPI_MSTR_SIZE				1
+#define SPI_PS_OFFSET				1
+#define SPI_PS_SIZE				1
+#define SPI_PCSDEC_OFFSET			2
+#define SPI_PCSDEC_SIZE				1
+#define SPI_FDIV_OFFSET				3
+#define SPI_FDIV_SIZE				1
+#define SPI_MODFDIS_OFFSET			4
+#define SPI_MODFDIS_SIZE			1
+#define SPI_WDRBT_OFFSET			5
+#define SPI_WDRBT_SIZE				1
+#define SPI_LLB_OFFSET				7
+#define SPI_LLB_SIZE				1
+#define SPI_PCS_OFFSET				16
+#define SPI_PCS_SIZE				4
+#define SPI_DLYBCS_OFFSET			24
+#define SPI_DLYBCS_SIZE				8
+
+/* Bitfields in RDR */
+#define SPI_RD_OFFSET				0
+#define SPI_RD_SIZE				16
+
+/* Bitfields in TDR */
+#define SPI_TD_OFFSET				0
+#define SPI_TD_SIZE				16
+
+/* Bitfields in SR */
+#define SPI_RDRF_OFFSET				0
+#define SPI_RDRF_SIZE				1
+#define SPI_TDRE_OFFSET				1
+#define SPI_TDRE_SIZE				1
+#define SPI_MODF_OFFSET				2
+#define SPI_MODF_SIZE				1
+#define SPI_OVRES_OFFSET			3
+#define SPI_OVRES_SIZE				1
+#define SPI_ENDRX_OFFSET			4
+#define SPI_ENDRX_SIZE				1
+#define SPI_ENDTX_OFFSET			5
+#define SPI_ENDTX_SIZE				1
+#define SPI_RXBUFF_OFFSET			6
+#define SPI_RXBUFF_SIZE				1
+#define SPI_TXBUFE_OFFSET			7
+#define SPI_TXBUFE_SIZE				1
+#define SPI_NSSR_OFFSET				8
+#define SPI_NSSR_SIZE				1
+#define SPI_TXEMPTY_OFFSET			9
+#define SPI_TXEMPTY_SIZE			1
+#define SPI_SPIENS_OFFSET			16
+#define SPI_SPIENS_SIZE				1
+
+/* Bitfields in CSR0 */
+#define SPI_CPOL_OFFSET				0
+#define SPI_CPOL_SIZE				1
+#define SPI_NCPHA_OFFSET			1
+#define SPI_NCPHA_SIZE				1
+#define SPI_CSAAT_OFFSET			3
+#define SPI_CSAAT_SIZE				1
+#define SPI_BITS_OFFSET				4
+#define SPI_BITS_SIZE				4
+#define SPI_SCBR_OFFSET				8
+#define SPI_SCBR_SIZE				8
+#define SPI_DLYBS_OFFSET			16
+#define SPI_DLYBS_SIZE				8
+#define SPI_DLYBCT_OFFSET			24
+#define SPI_DLYBCT_SIZE				8
+
+/* Bitfields in RCR */
+#define SPI_RXCTR_OFFSET			0
+#define SPI_RXCTR_SIZE				16
+
+/* Bitfields in TCR */
+#define SPI_TXCTR_OFFSET			0
+#define SPI_TXCTR_SIZE				16
+
+/* Bitfields in RNCR */
+#define SPI_RXNCR_OFFSET			0
+#define SPI_RXNCR_SIZE				16
+
+/* Bitfields in TNCR */
+#define SPI_TXNCR_OFFSET			0
+#define SPI_TXNCR_SIZE				16
+
+/* Bitfields in PTCR */
+#define SPI_RXTEN_OFFSET			0
+#define SPI_RXTEN_SIZE				1
+#define SPI_RXTDIS_OFFSET			1
+#define SPI_RXTDIS_SIZE				1
+#define SPI_TXTEN_OFFSET			8
+#define SPI_TXTEN_SIZE				1
+#define SPI_TXTDIS_OFFSET			9
+#define SPI_TXTDIS_SIZE				1
+
+/* Constants for BITS */
+#define SPI_BITS_8_BPT				0
+#define SPI_BITS_9_BPT				1
+#define SPI_BITS_10_BPT				2
+#define SPI_BITS_11_BPT				3
+#define SPI_BITS_12_BPT				4
+#define SPI_BITS_13_BPT				5
+#define SPI_BITS_14_BPT				6
+#define SPI_BITS_15_BPT				7
+#define SPI_BITS_16_BPT				8
+
+/* Bit manipulation macros */
+#define SPI_BIT(name) \
+	(1 << SPI_##name##_OFFSET)
+#define SPI_BF(name, value) \
+	(((value) & ((1 << SPI_##name##_SIZE) - 1)) << SPI_##name##_OFFSET)
+#define SPI_BFEXT(name, value) \
+	(((value) >> SPI_##name##_OFFSET) & ((1 << SPI_##name##_SIZE) - 1))
+#define SPI_BFINS(name, value, old) \
+	(((old) & ~(((1 << SPI_##name##_SIZE) - 1) << SPI_##name##_OFFSET)) \
+	  | SPI_BF(name, value))
+
+/* Register access macros */
+#ifdef CONFIG_AVR32
+#define spi_readl(port, reg) \
+	__raw_readl((port)->regs + SPI_##reg)
+#define spi_writel(port, reg, value) \
+	__raw_writel((value), (port)->regs + SPI_##reg)
+#else
+#define spi_readl(port, reg) \
+	readl_relaxed((port)->regs + SPI_##reg)
+#define spi_writel(port, reg, value) \
+	writel_relaxed((value), (port)->regs + SPI_##reg)
+#endif
+/* use PIO for small transfers, avoiding DMA setup/teardown overhead and
+ * cache operations; better heuristics consider wordsize and bitrate.
+ */
+#define DMA_MIN_BYTES	16
+
+#define SPI_DMA_TIMEOUT		(msecs_to_jiffies(1000))
+
+#define AUTOSUSPEND_TIMEOUT	2000
+
+struct atmel_spi_dma {
+	struct dma_chan			*chan_rx;
+	struct dma_chan			*chan_tx;
+	struct scatterlist		sgrx;
+	struct scatterlist		sgtx;
+	struct dma_async_tx_descriptor	*data_desc_rx;
+	struct dma_async_tx_descriptor	*data_desc_tx;
+
+	struct at_dma_slave	dma_slave;
+};
+
+struct atmel_spi_caps {
+	bool	is_spi2;
+	bool	has_wdrbt;
+	bool	has_dma_support;
+};
+
+/*
+ * The core SPI transfer engine just talks to a register bank to set up
+ * DMA transfers; transfer queue progress is driven by IRQs.  The clock
+ * framework provides the base clock, subdivided for each spi_device.
+ */
+struct atmel_spi {
+	spinlock_t		lock;
+	unsigned long		flags;
+
+	phys_addr_t		phybase;
+	void __iomem		*regs;
+	int			irq;
+	struct clk		*clk;
+	struct platform_device	*pdev;
+
+	struct spi_transfer	*current_transfer;
+	int			current_remaining_bytes;
+	int			done_status;
+
+	struct completion	xfer_completion;
+
+	/* scratch buffer */
+	void			*buffer;
+	dma_addr_t		buffer_dma;
+
+	struct atmel_spi_caps	caps;
+
+	bool			use_dma;
+	bool			use_pdc;
+	/* dmaengine data */
+	struct atmel_spi_dma	dma;
+
+	bool			keep_cs;
+	bool			cs_active;
+};
+
+/* Controller-specific per-slave state */
+struct atmel_spi_device {
+	unsigned int		npcs_pin;
+	u32			csr;
+};
+
+#define BUFFER_SIZE		PAGE_SIZE
+#define INVALID_DMA_ADDRESS	0xffffffff
+
+/*
+ * Version 2 of the SPI controller has
+ *  - CR.LASTXFER
+ *  - SPI_MR.DIV32 may become FDIV or must-be-zero (here: always zero)
+ *  - SPI_SR.TXEMPTY, SPI_SR.NSSR (and corresponding irqs)
+ *  - SPI_CSRx.CSAAT
+ *  - SPI_CSRx.SBCR allows faster clocking
+ */
+static bool atmel_spi_is_v2(struct atmel_spi *as)
+{
+	return as->caps.is_spi2;
+}
+
+/*
+ * Earlier SPI controllers (e.g. on at91rm9200) have a design bug whereby
+ * they assume that spi slave device state will not change on deselect, so
+ * that automagic deselection is OK.  ("NPCSx rises if no data is to be
+ * transmitted")  Not so!  Workaround uses nCSx pins as GPIOs; or newer
+ * controllers have CSAAT and friends.
+ *
+ * Since the CSAAT functionality is a bit weird on newer controllers as
+ * well, we use GPIO to control nCSx pins on all controllers, updating
+ * MR.PCS to avoid confusing the controller.  Using GPIOs also lets us
+ * support active-high chipselects despite the controller's belief that
+ * only active-low devices/systems exists.
+ *
+ * However, at91rm9200 has a second erratum whereby nCS0 doesn't work
+ * right when driven with GPIO.  ("Mode Fault does not allow more than one
+ * Master on Chip Select 0.")  No workaround exists for that ... so for
+ * nCS0 on that chip, we (a) don't use the GPIO, (b) can't support CS_HIGH,
+ * and (c) will trigger that first erratum in some cases.
+ */
+
+static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
+{
+	struct atmel_spi_device *asd = spi->controller_state;
+	unsigned active = spi->mode & SPI_CS_HIGH;
+	u32 mr;
+
+	if (atmel_spi_is_v2(as)) {
+		spi_writel(as, CSR0 + 4 * spi->chip_select, asd->csr);
+		/* For the low SPI version, there is a issue that PDC transfer
+		 * on CS1,2,3 needs SPI_CSR0.BITS config as SPI_CSR1,2,3.BITS
+		 */
+		spi_writel(as, CSR0, asd->csr);
+		if (as->caps.has_wdrbt) {
+			spi_writel(as, MR,
+					SPI_BF(PCS, ~(0x01 << spi->chip_select))
+					| SPI_BIT(WDRBT)
+					| SPI_BIT(MODFDIS)
+					| SPI_BIT(MSTR));
+		} else {
+			spi_writel(as, MR,
+					SPI_BF(PCS, ~(0x01 << spi->chip_select))
+					| SPI_BIT(MODFDIS)
+					| SPI_BIT(MSTR));
+		}
+
+		mr = spi_readl(as, MR);
+		gpio_set_value(asd->npcs_pin, active);
+	} else {
+		u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
+		int i;
+		u32 csr;
+
+		/* Make sure clock polarity is correct */
+		for (i = 0; i < spi->master->num_chipselect; i++) {
+			csr = spi_readl(as, CSR0 + 4 * i);
+			if ((csr ^ cpol) & SPI_BIT(CPOL))
+				spi_writel(as, CSR0 + 4 * i,
+						csr ^ SPI_BIT(CPOL));
+		}
+
+		mr = spi_readl(as, MR);
+		mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr);
+		if (spi->chip_select != 0)
+			gpio_set_value(asd->npcs_pin, active);
+		spi_writel(as, MR, mr);
+	}
+
+	dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
+			asd->npcs_pin, active ? " (high)" : "",
+			mr);
+}
+
+static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
+{
+	struct atmel_spi_device *asd = spi->controller_state;
+	unsigned active = spi->mode & SPI_CS_HIGH;
+	u32 mr;
+
+	/* only deactivate *this* device; sometimes transfers to
+	 * another device may be active when this routine is called.
+	 */
+	mr = spi_readl(as, MR);
+	if (~SPI_BFEXT(PCS, mr) & (1 << spi->chip_select)) {
+		mr = SPI_BFINS(PCS, 0xf, mr);
+		spi_writel(as, MR, mr);
+	}
+
+	dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
+			asd->npcs_pin, active ? " (low)" : "",
+			mr);
+
+	if (atmel_spi_is_v2(as) || spi->chip_select != 0)
+		gpio_set_value(asd->npcs_pin, !active);
+}
+
+static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
+{
+	spin_lock_irqsave(&as->lock, as->flags);
+}
+
+static void atmel_spi_unlock(struct atmel_spi *as) __releases(&as->lock)
+{
+	spin_unlock_irqrestore(&as->lock, as->flags);
+}
+
+static inline bool atmel_spi_use_dma(struct atmel_spi *as,
+				struct spi_transfer *xfer)
+{
+	return as->use_dma && xfer->len >= DMA_MIN_BYTES;
+}
+
+static int atmel_spi_dma_slave_config(struct atmel_spi *as,
+				struct dma_slave_config *slave_config,
+				u8 bits_per_word)
+{
+	int err = 0;
+
+	if (bits_per_word > 8) {
+		slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+		slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+	} else {
+		slave_config->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+		slave_config->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+	}
+
+	slave_config->dst_addr = (dma_addr_t)as->phybase + SPI_TDR;
+	slave_config->src_addr = (dma_addr_t)as->phybase + SPI_RDR;
+	slave_config->src_maxburst = 1;
+	slave_config->dst_maxburst = 1;
+	slave_config->device_fc = false;
+
+	slave_config->direction = DMA_MEM_TO_DEV;
+	if (dmaengine_slave_config(as->dma.chan_tx, slave_config)) {
+		dev_err(&as->pdev->dev,
+			"failed to configure tx dma channel\n");
+		err = -EINVAL;
+	}
+
+	slave_config->direction = DMA_DEV_TO_MEM;
+	if (dmaengine_slave_config(as->dma.chan_rx, slave_config)) {
+		dev_err(&as->pdev->dev,
+			"failed to configure rx dma channel\n");
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+static int atmel_spi_configure_dma(struct atmel_spi *as)
+{
+	struct dma_slave_config	slave_config;
+	struct device *dev = &as->pdev->dev;
+	int err;
+
+	dma_cap_mask_t mask;
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	as->dma.chan_tx = dma_request_slave_channel_reason(dev, "tx");
+	if (IS_ERR(as->dma.chan_tx)) {
+		err = PTR_ERR(as->dma.chan_tx);
+		if (err == -EPROBE_DEFER) {
+			dev_warn(dev, "no DMA channel available at the moment\n");
+			return err;
+		}
+		dev_err(dev,
+			"DMA TX channel not available, SPI unable to use DMA\n");
+		err = -EBUSY;
+		goto error;
+	}
+
+	/*
+	 * No reason to check EPROBE_DEFER here since we have already requested
+	 * tx channel. If it fails here, it's for another reason.
+	 */
+	as->dma.chan_rx = dma_request_slave_channel(dev, "rx");
+
+	if (!as->dma.chan_rx) {
+		dev_err(dev,
+			"DMA RX channel not available, SPI unable to use DMA\n");
+		err = -EBUSY;
+		goto error;
+	}
+
+	err = atmel_spi_dma_slave_config(as, &slave_config, 8);
+	if (err)
+		goto error;
+
+	dev_info(&as->pdev->dev,
+			"Using %s (tx) and %s (rx) for DMA transfers\n",
+			dma_chan_name(as->dma.chan_tx),
+			dma_chan_name(as->dma.chan_rx));
+	return 0;
+error:
+	if (as->dma.chan_rx)
+		dma_release_channel(as->dma.chan_rx);
+	if (!IS_ERR(as->dma.chan_tx))
+		dma_release_channel(as->dma.chan_tx);
+	return err;
+}
+
+static void atmel_spi_stop_dma(struct atmel_spi *as)
+{
+	if (as->dma.chan_rx)
+		dmaengine_terminate_all(as->dma.chan_rx);
+	if (as->dma.chan_tx)
+		dmaengine_terminate_all(as->dma.chan_tx);
+}
+
+static void atmel_spi_release_dma(struct atmel_spi *as)
+{
+	if (as->dma.chan_rx)
+		dma_release_channel(as->dma.chan_rx);
+	if (as->dma.chan_tx)
+		dma_release_channel(as->dma.chan_tx);
+}
+
+/* This function is called by the DMA driver from tasklet context */
+static void dma_callback(void *data)
+{
+	struct spi_master	*master = data;
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+
+	complete(&as->xfer_completion);
+}
+
+/*
+ * Next transfer using PIO.
+ */
+static void atmel_spi_next_xfer_pio(struct spi_master *master,
+				struct spi_transfer *xfer)
+{
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	unsigned long xfer_pos = xfer->len - as->current_remaining_bytes;
+
+	dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_pio\n");
+
+	/* Make sure data is not remaining in RDR */
+	spi_readl(as, RDR);
+	while (spi_readl(as, SR) & SPI_BIT(RDRF)) {
+		spi_readl(as, RDR);
+		cpu_relax();
+	}
+
+	if (xfer->tx_buf) {
+		if (xfer->bits_per_word > 8)
+			spi_writel(as, TDR, *(u16 *)(xfer->tx_buf + xfer_pos));
+		else
+			spi_writel(as, TDR, *(u8 *)(xfer->tx_buf + xfer_pos));
+	} else {
+		spi_writel(as, TDR, 0);
+	}
+
+	dev_dbg(master->dev.parent,
+		"  start pio xfer %p: len %u tx %p rx %p bitpw %d\n",
+		xfer, xfer->len, xfer->tx_buf, xfer->rx_buf,
+		xfer->bits_per_word);
+
+	/* Enable relevant interrupts */
+	spi_writel(as, IER, SPI_BIT(RDRF) | SPI_BIT(OVRES));
+}
+
+/*
+ * Submit next transfer for DMA.
+ */
+static int atmel_spi_next_xfer_dma_submit(struct spi_master *master,
+				struct spi_transfer *xfer,
+				u32 *plen)
+{
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	struct dma_chan		*rxchan = as->dma.chan_rx;
+	struct dma_chan		*txchan = as->dma.chan_tx;
+	struct dma_async_tx_descriptor *rxdesc;
+	struct dma_async_tx_descriptor *txdesc;
+	struct dma_slave_config	slave_config;
+	dma_cookie_t		cookie;
+	u32	len = *plen;
+
+	dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_dma_submit\n");
+
+	/* Check that the channels are available */
+	if (!rxchan || !txchan)
+		return -ENODEV;
+
+	/* release lock for DMA operations */
+	atmel_spi_unlock(as);
+
+	/* prepare the RX dma transfer */
+	sg_init_table(&as->dma.sgrx, 1);
+	if (xfer->rx_buf) {
+		as->dma.sgrx.dma_address = xfer->rx_dma + xfer->len - *plen;
+	} else {
+		as->dma.sgrx.dma_address = as->buffer_dma;
+		if (len > BUFFER_SIZE)
+			len = BUFFER_SIZE;
+	}
+
+	/* prepare the TX dma transfer */
+	sg_init_table(&as->dma.sgtx, 1);
+	if (xfer->tx_buf) {
+		as->dma.sgtx.dma_address = xfer->tx_dma + xfer->len - *plen;
+	} else {
+		as->dma.sgtx.dma_address = as->buffer_dma;
+		if (len > BUFFER_SIZE)
+			len = BUFFER_SIZE;
+		memset(as->buffer, 0, len);
+	}
+
+	sg_dma_len(&as->dma.sgtx) = len;
+	sg_dma_len(&as->dma.sgrx) = len;
+
+	*plen = len;
+
+	if (atmel_spi_dma_slave_config(as, &slave_config, 8))
+		goto err_exit;
+
+	/* Send both scatterlists */
+	rxdesc = dmaengine_prep_slave_sg(rxchan, &as->dma.sgrx, 1,
+					 DMA_FROM_DEVICE,
+					 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!rxdesc)
+		goto err_dma;
+
+	txdesc = dmaengine_prep_slave_sg(txchan, &as->dma.sgtx, 1,
+					 DMA_TO_DEVICE,
+					 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!txdesc)
+		goto err_dma;
+
+	dev_dbg(master->dev.parent,
+		"  start dma xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
+		xfer, xfer->len, xfer->tx_buf, (unsigned long long)xfer->tx_dma,
+		xfer->rx_buf, (unsigned long long)xfer->rx_dma);
+
+	/* Enable relevant interrupts */
+	spi_writel(as, IER, SPI_BIT(OVRES));
+
+	/* Put the callback on the RX transfer only, that should finish last */
+	rxdesc->callback = dma_callback;
+	rxdesc->callback_param = master;
+
+	/* Submit and fire RX and TX with TX last so we're ready to read! */
+	cookie = rxdesc->tx_submit(rxdesc);
+	if (dma_submit_error(cookie))
+		goto err_dma;
+	cookie = txdesc->tx_submit(txdesc);
+	if (dma_submit_error(cookie))
+		goto err_dma;
+	rxchan->device->device_issue_pending(rxchan);
+	txchan->device->device_issue_pending(txchan);
+
+	/* take back lock */
+	atmel_spi_lock(as);
+	return 0;
+
+err_dma:
+	spi_writel(as, IDR, SPI_BIT(OVRES));
+	atmel_spi_stop_dma(as);
+err_exit:
+	atmel_spi_lock(as);
+	return -ENOMEM;
+}
+
+static void atmel_spi_next_xfer_data(struct spi_master *master,
+				struct spi_transfer *xfer,
+				dma_addr_t *tx_dma,
+				dma_addr_t *rx_dma,
+				u32 *plen)
+{
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	u32			len = *plen;
+
+	/* use scratch buffer only when rx or tx data is unspecified */
+	if (xfer->rx_buf)
+		*rx_dma = xfer->rx_dma + xfer->len - *plen;
+	else {
+		*rx_dma = as->buffer_dma;
+		if (len > BUFFER_SIZE)
+			len = BUFFER_SIZE;
+	}
+
+	if (xfer->tx_buf)
+		*tx_dma = xfer->tx_dma + xfer->len - *plen;
+	else {
+		*tx_dma = as->buffer_dma;
+		if (len > BUFFER_SIZE)
+			len = BUFFER_SIZE;
+		memset(as->buffer, 0, len);
+		dma_sync_single_for_device(&as->pdev->dev,
+				as->buffer_dma, len, DMA_TO_DEVICE);
+	}
+
+	*plen = len;
+}
+
+static int atmel_spi_set_xfer_speed(struct atmel_spi *as,
+				    struct spi_device *spi,
+				    struct spi_transfer *xfer)
+{
+	u32			scbr, csr;
+	unsigned long		bus_hz;
+
+	/* v1 chips start out at half the peripheral bus speed. */
+	bus_hz = clk_get_rate(as->clk);
+	if (!atmel_spi_is_v2(as))
+		bus_hz /= 2;
+
+	/*
+	 * Calculate the lowest divider that satisfies the
+	 * constraint, assuming div32/fdiv/mbz == 0.
+	 */
+	if (xfer->speed_hz)
+		scbr = DIV_ROUND_UP(bus_hz, xfer->speed_hz);
+	else
+		/*
+		 * This can happend if max_speed is null.
+		 * In this case, we set the lowest possible speed
+		 */
+		scbr = 0xff;
+
+	/*
+	 * If the resulting divider doesn't fit into the
+	 * register bitfield, we can't satisfy the constraint.
+	 */
+	if (scbr >= (1 << SPI_SCBR_SIZE)) {
+		dev_err(&spi->dev,
+			"setup: %d Hz too slow, scbr %u; min %ld Hz\n",
+			xfer->speed_hz, scbr, bus_hz/255);
+		return -EINVAL;
+	}
+	if (scbr == 0) {
+		dev_err(&spi->dev,
+			"setup: %d Hz too high, scbr %u; max %ld Hz\n",
+			xfer->speed_hz, scbr, bus_hz);
+		return -EINVAL;
+	}
+	csr = spi_readl(as, CSR0 + 4 * spi->chip_select);
+	csr = SPI_BFINS(SCBR, scbr, csr);
+	spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
+
+	return 0;
+}
+
+/*
+ * Submit next transfer for PDC.
+ * lock is held, spi irq is blocked
+ */
+static void atmel_spi_pdc_next_xfer(struct spi_master *master,
+					struct spi_message *msg,
+					struct spi_transfer *xfer)
+{
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	u32			len;
+	dma_addr_t		tx_dma, rx_dma;
+
+	spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+
+	len = as->current_remaining_bytes;
+	atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
+	as->current_remaining_bytes -= len;
+
+	spi_writel(as, RPR, rx_dma);
+	spi_writel(as, TPR, tx_dma);
+
+	if (msg->spi->bits_per_word > 8)
+		len >>= 1;
+	spi_writel(as, RCR, len);
+	spi_writel(as, TCR, len);
+
+	dev_dbg(&msg->spi->dev,
+		"  start xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
+		xfer, xfer->len, xfer->tx_buf,
+		(unsigned long long)xfer->tx_dma, xfer->rx_buf,
+		(unsigned long long)xfer->rx_dma);
+
+	if (as->current_remaining_bytes) {
+		len = as->current_remaining_bytes;
+		atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
+		as->current_remaining_bytes -= len;
+
+		spi_writel(as, RNPR, rx_dma);
+		spi_writel(as, TNPR, tx_dma);
+
+		if (msg->spi->bits_per_word > 8)
+			len >>= 1;
+		spi_writel(as, RNCR, len);
+		spi_writel(as, TNCR, len);
+
+		dev_dbg(&msg->spi->dev,
+			"  next xfer %p: len %u tx %p/%08llx rx %p/%08llx\n",
+			xfer, xfer->len, xfer->tx_buf,
+			(unsigned long long)xfer->tx_dma, xfer->rx_buf,
+			(unsigned long long)xfer->rx_dma);
+	}
+
+	/* REVISIT: We're waiting for RXBUFF before we start the next
+	 * transfer because we need to handle some difficult timing
+	 * issues otherwise. If we wait for TXBUFE in one transfer and
+	 * then starts waiting for RXBUFF in the next, it's difficult
+	 * to tell the difference between the RXBUFF interrupt we're
+	 * actually waiting for and the RXBUFF interrupt of the
+	 * previous transfer.
+	 *
+	 * It should be doable, though. Just not now...
+	 */
+	spi_writel(as, IER, SPI_BIT(RXBUFF) | SPI_BIT(OVRES));
+	spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
+}
+
+/*
+ * For DMA, tx_buf/tx_dma have the same relationship as rx_buf/rx_dma:
+ *  - The buffer is either valid for CPU access, else NULL
+ *  - If the buffer is valid, so is its DMA address
+ *
+ * This driver manages the dma address unless message->is_dma_mapped.
+ */
+static int
+atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
+{
+	struct device	*dev = &as->pdev->dev;
+
+	xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
+	if (xfer->tx_buf) {
+		/* tx_buf is a const void* where we need a void * for the dma
+		 * mapping */
+		void *nonconst_tx = (void *)xfer->tx_buf;
+
+		xfer->tx_dma = dma_map_single(dev,
+				nonconst_tx, xfer->len,
+				DMA_TO_DEVICE);
+		if (dma_mapping_error(dev, xfer->tx_dma))
+			return -ENOMEM;
+	}
+	if (xfer->rx_buf) {
+		xfer->rx_dma = dma_map_single(dev,
+				xfer->rx_buf, xfer->len,
+				DMA_FROM_DEVICE);
+		if (dma_mapping_error(dev, xfer->rx_dma)) {
+			if (xfer->tx_buf)
+				dma_unmap_single(dev,
+						xfer->tx_dma, xfer->len,
+						DMA_TO_DEVICE);
+			return -ENOMEM;
+		}
+	}
+	return 0;
+}
+
+static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
+				     struct spi_transfer *xfer)
+{
+	if (xfer->tx_dma != INVALID_DMA_ADDRESS)
+		dma_unmap_single(master->dev.parent, xfer->tx_dma,
+				 xfer->len, DMA_TO_DEVICE);
+	if (xfer->rx_dma != INVALID_DMA_ADDRESS)
+		dma_unmap_single(master->dev.parent, xfer->rx_dma,
+				 xfer->len, DMA_FROM_DEVICE);
+}
+
+static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as)
+{
+	spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+}
+
+/* Called from IRQ
+ *
+ * Must update "current_remaining_bytes" to keep track of data
+ * to transfer.
+ */
+static void
+atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer)
+{
+	u8		*rxp;
+	u16		*rxp16;
+	unsigned long	xfer_pos = xfer->len - as->current_remaining_bytes;
+
+	if (xfer->rx_buf) {
+		if (xfer->bits_per_word > 8) {
+			rxp16 = (u16 *)(((u8 *)xfer->rx_buf) + xfer_pos);
+			*rxp16 = spi_readl(as, RDR);
+		} else {
+			rxp = ((u8 *)xfer->rx_buf) + xfer_pos;
+			*rxp = spi_readl(as, RDR);
+		}
+	} else {
+		spi_readl(as, RDR);
+	}
+	if (xfer->bits_per_word > 8) {
+		if (as->current_remaining_bytes > 2)
+			as->current_remaining_bytes -= 2;
+		else
+			as->current_remaining_bytes = 0;
+	} else {
+		as->current_remaining_bytes--;
+	}
+}
+
+/* Interrupt
+ *
+ * No need for locking in this Interrupt handler: done_status is the
+ * only information modified.
+ */
+static irqreturn_t
+atmel_spi_pio_interrupt(int irq, void *dev_id)
+{
+	struct spi_master	*master = dev_id;
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	u32			status, pending, imr;
+	struct spi_transfer	*xfer;
+	int			ret = IRQ_NONE;
+
+	imr = spi_readl(as, IMR);
+	status = spi_readl(as, SR);
+	pending = status & imr;
+
+	if (pending & SPI_BIT(OVRES)) {
+		ret = IRQ_HANDLED;
+		spi_writel(as, IDR, SPI_BIT(OVRES));
+		dev_warn(master->dev.parent, "overrun\n");
+
+		/*
+		 * When we get an overrun, we disregard the current
+		 * transfer. Data will not be copied back from any
+		 * bounce buffer and msg->actual_len will not be
+		 * updated with the last xfer.
+		 *
+		 * We will also not process any remaning transfers in
+		 * the message.
+		 */
+		as->done_status = -EIO;
+		smp_wmb();
+
+		/* Clear any overrun happening while cleaning up */
+		spi_readl(as, SR);
+
+		complete(&as->xfer_completion);
+
+	} else if (pending & SPI_BIT(RDRF)) {
+		atmel_spi_lock(as);
+
+		if (as->current_remaining_bytes) {
+			ret = IRQ_HANDLED;
+			xfer = as->current_transfer;
+			atmel_spi_pump_pio_data(as, xfer);
+			if (!as->current_remaining_bytes)
+				spi_writel(as, IDR, pending);
+
+			complete(&as->xfer_completion);
+		}
+
+		atmel_spi_unlock(as);
+	} else {
+		WARN_ONCE(pending, "IRQ not handled, pending = %x\n", pending);
+		ret = IRQ_HANDLED;
+		spi_writel(as, IDR, pending);
+	}
+
+	return ret;
+}
+
+static irqreturn_t
+atmel_spi_pdc_interrupt(int irq, void *dev_id)
+{
+	struct spi_master	*master = dev_id;
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+	u32			status, pending, imr;
+	int			ret = IRQ_NONE;
+
+	imr = spi_readl(as, IMR);
+	status = spi_readl(as, SR);
+	pending = status & imr;
+
+	if (pending & SPI_BIT(OVRES)) {
+
+		ret = IRQ_HANDLED;
+
+		spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
+				     | SPI_BIT(OVRES)));
+
+		/* Clear any overrun happening while cleaning up */
+		spi_readl(as, SR);
+
+		as->done_status = -EIO;
+
+		complete(&as->xfer_completion);
+
+	} else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
+		ret = IRQ_HANDLED;
+
+		spi_writel(as, IDR, pending);
+
+		complete(&as->xfer_completion);
+	}
+
+	return ret;
+}
+
+static int atmel_spi_setup(struct spi_device *spi)
+{
+	struct atmel_spi	*as;
+	struct atmel_spi_device	*asd;
+	u32			csr;
+	unsigned int		bits = spi->bits_per_word;
+	unsigned int		npcs_pin;
+	int			ret;
+
+	as = spi_master_get_devdata(spi->master);
+
+	/* see notes above re chipselect */
+	if (!atmel_spi_is_v2(as)
+			&& spi->chip_select == 0
+			&& (spi->mode & SPI_CS_HIGH)) {
+		dev_dbg(&spi->dev, "setup: can't be active-high\n");
+		return -EINVAL;
+	}
+
+	csr = SPI_BF(BITS, bits - 8);
+	if (spi->mode & SPI_CPOL)
+		csr |= SPI_BIT(CPOL);
+	if (!(spi->mode & SPI_CPHA))
+		csr |= SPI_BIT(NCPHA);
+
+	/* DLYBS is mostly irrelevant since we manage chipselect using GPIOs.
+	 *
+	 * DLYBCT would add delays between words, slowing down transfers.
+	 * It could potentially be useful to cope with DMA bottlenecks, but
+	 * in those cases it's probably best to just use a lower bitrate.
+	 */
+	csr |= SPI_BF(DLYBS, 0);
+	csr |= SPI_BF(DLYBCT, 0);
+
+	/* chipselect must have been muxed as GPIO (e.g. in board setup) */
+	npcs_pin = (unsigned long)spi->controller_data;
+
+	if (gpio_is_valid(spi->cs_gpio))
+		npcs_pin = spi->cs_gpio;
+
+	asd = spi->controller_state;
+	if (!asd) {
+		asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
+		if (!asd)
+			return -ENOMEM;
+
+		ret = gpio_request(npcs_pin, dev_name(&spi->dev));
+		if (ret) {
+			kfree(asd);
+			return ret;
+		}
+
+		asd->npcs_pin = npcs_pin;
+		spi->controller_state = asd;
+		gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
+	}
+
+	asd->csr = csr;
+
+	dev_dbg(&spi->dev,
+		"setup: bpw %u mode 0x%x -> csr%d %08x\n",
+		bits, spi->mode, spi->chip_select, csr);
+
+	if (!atmel_spi_is_v2(as))
+		spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
+
+	return 0;
+}
+
+static int atmel_spi_one_transfer(struct spi_master *master,
+					struct spi_message *msg,
+					struct spi_transfer *xfer)
+{
+	struct atmel_spi	*as;
+	struct spi_device	*spi = msg->spi;
+	u8			bits;
+	u32			len;
+	struct atmel_spi_device	*asd;
+	int			timeout;
+	int			ret;
+	unsigned long		dma_timeout;
+
+	as = spi_master_get_devdata(master);
+
+	if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
+		dev_dbg(&spi->dev, "missing rx or tx buf\n");
+		return -EINVAL;
+	}
+
+	if (xfer->bits_per_word) {
+		asd = spi->controller_state;
+		bits = (asd->csr >> 4) & 0xf;
+		if (bits != xfer->bits_per_word - 8) {
+			dev_dbg(&spi->dev,
+			"you can't yet change bits_per_word in transfers\n");
+			return -ENOPROTOOPT;
+		}
+	}
+
+	/*
+	 * DMA map early, for performance (empties dcache ASAP) and
+	 * better fault reporting.
+	 */
+	if ((!msg->is_dma_mapped)
+		&& (atmel_spi_use_dma(as, xfer)	|| as->use_pdc)) {
+		if (atmel_spi_dma_map_xfer(as, xfer) < 0)
+			return -ENOMEM;
+	}
+
+	atmel_spi_set_xfer_speed(as, msg->spi, xfer);
+
+	as->done_status = 0;
+	as->current_transfer = xfer;
+	as->current_remaining_bytes = xfer->len;
+	while (as->current_remaining_bytes) {
+		reinit_completion(&as->xfer_completion);
+
+		if (as->use_pdc) {
+			atmel_spi_pdc_next_xfer(master, msg, xfer);
+		} else if (atmel_spi_use_dma(as, xfer)) {
+			len = as->current_remaining_bytes;
+			ret = atmel_spi_next_xfer_dma_submit(master,
+								xfer, &len);
+			if (ret) {
+				dev_err(&spi->dev,
+					"unable to use DMA, fallback to PIO\n");
+				atmel_spi_next_xfer_pio(master, xfer);
+			} else {
+				as->current_remaining_bytes -= len;
+				if (as->current_remaining_bytes < 0)
+					as->current_remaining_bytes = 0;
+			}
+		} else {
+			atmel_spi_next_xfer_pio(master, xfer);
+		}
+
+		/* interrupts are disabled, so free the lock for schedule */
+		atmel_spi_unlock(as);
+		dma_timeout = wait_for_completion_timeout(&as->xfer_completion,
+							  SPI_DMA_TIMEOUT);
+		atmel_spi_lock(as);
+		if (WARN_ON(dma_timeout == 0)) {
+			dev_err(&spi->dev, "spi transfer timeout\n");
+			as->done_status = -EIO;
+		}
+
+		if (as->done_status)
+			break;
+	}
+
+	if (as->done_status) {
+		if (as->use_pdc) {
+			dev_warn(master->dev.parent,
+				"overrun (%u/%u remaining)\n",
+				spi_readl(as, TCR), spi_readl(as, RCR));
+
+			/*
+			 * Clean up DMA registers and make sure the data
+			 * registers are empty.
+			 */
+			spi_writel(as, RNCR, 0);
+			spi_writel(as, TNCR, 0);
+			spi_writel(as, RCR, 0);
+			spi_writel(as, TCR, 0);
+			for (timeout = 1000; timeout; timeout--)
+				if (spi_readl(as, SR) & SPI_BIT(TXEMPTY))
+					break;
+			if (!timeout)
+				dev_warn(master->dev.parent,
+					 "timeout waiting for TXEMPTY");
+			while (spi_readl(as, SR) & SPI_BIT(RDRF))
+				spi_readl(as, RDR);
+
+			/* Clear any overrun happening while cleaning up */
+			spi_readl(as, SR);
+
+		} else if (atmel_spi_use_dma(as, xfer)) {
+			atmel_spi_stop_dma(as);
+		}
+
+		if (!msg->is_dma_mapped
+			&& (atmel_spi_use_dma(as, xfer) || as->use_pdc))
+			atmel_spi_dma_unmap_xfer(master, xfer);
+
+		return 0;
+
+	} else {
+		/* only update length if no error */
+		msg->actual_length += xfer->len;
+	}
+
+	if (!msg->is_dma_mapped
+		&& (atmel_spi_use_dma(as, xfer) || as->use_pdc))
+		atmel_spi_dma_unmap_xfer(master, xfer);
+
+	if (xfer->delay_usecs)
+		udelay(xfer->delay_usecs);
+
+	if (xfer->cs_change) {
+		if (list_is_last(&xfer->transfer_list,
+				 &msg->transfers)) {
+			as->keep_cs = true;
+		} else {
+			as->cs_active = !as->cs_active;
+			if (as->cs_active)
+				cs_activate(as, msg->spi);
+			else
+				cs_deactivate(as, msg->spi);
+		}
+	}
+
+	return 0;
+}
+
+static int atmel_spi_transfer_one_message(struct spi_master *master,
+						struct spi_message *msg)
+{
+	struct atmel_spi *as;
+	struct spi_transfer *xfer;
+	struct spi_device *spi = msg->spi;
+	int ret = 0;
+
+	as = spi_master_get_devdata(master);
+
+	dev_dbg(&spi->dev, "new message %p submitted for %s\n",
+					msg, dev_name(&spi->dev));
+
+	atmel_spi_lock(as);
+	cs_activate(as, spi);
+
+	as->cs_active = true;
+	as->keep_cs = false;
+
+	msg->status = 0;
+	msg->actual_length = 0;
+
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		ret = atmel_spi_one_transfer(master, msg, xfer);
+		if (ret)
+			goto msg_done;
+	}
+
+	if (as->use_pdc)
+		atmel_spi_disable_pdc_transfer(as);
+
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		dev_dbg(&spi->dev,
+			"  xfer %p: len %u tx %p/%pad rx %p/%pad\n",
+			xfer, xfer->len,
+			xfer->tx_buf, &xfer->tx_dma,
+			xfer->rx_buf, &xfer->rx_dma);
+	}
+
+msg_done:
+	if (!as->keep_cs)
+		cs_deactivate(as, msg->spi);
+
+	atmel_spi_unlock(as);
+
+	msg->status = as->done_status;
+	spi_finalize_current_message(spi->master);
+
+	return ret;
+}
+
+static void atmel_spi_cleanup(struct spi_device *spi)
+{
+	struct atmel_spi_device	*asd = spi->controller_state;
+	unsigned		gpio = (unsigned long) spi->controller_data;
+
+	if (!asd)
+		return;
+
+	spi->controller_state = NULL;
+	gpio_free(gpio);
+	kfree(asd);
+}
+
+static inline unsigned int atmel_get_version(struct atmel_spi *as)
+{
+	return spi_readl(as, VERSION) & 0x00000fff;
+}
+
+static void atmel_get_caps(struct atmel_spi *as)
+{
+	unsigned int version;
+
+	version = atmel_get_version(as);
+	dev_info(&as->pdev->dev, "version: 0x%x\n", version);
+
+	as->caps.is_spi2 = version > 0x121;
+	as->caps.has_wdrbt = version >= 0x210;
+	as->caps.has_dma_support = version >= 0x212;
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int atmel_spi_probe(struct platform_device *pdev)
+{
+	struct resource		*regs;
+	int			irq;
+	struct clk		*clk;
+	int			ret;
+	struct spi_master	*master;
+	struct atmel_spi	*as;
+
+	/* Select default pin state */
+	pinctrl_pm_select_default_state(&pdev->dev);
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!regs)
+		return -ENXIO;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	clk = devm_clk_get(&pdev->dev, "spi_clk");
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	/* setup spi core then atmel-specific driver state */
+	ret = -ENOMEM;
+	master = spi_alloc_master(&pdev->dev, sizeof(*as));
+	if (!master)
+		goto out_free;
+
+	/* the spi->mode bits understood by this driver: */
+	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 16);
+	master->dev.of_node = pdev->dev.of_node;
+	master->bus_num = pdev->id;
+	master->num_chipselect = master->dev.of_node ? 0 : 4;
+	master->setup = atmel_spi_setup;
+	master->transfer_one_message = atmel_spi_transfer_one_message;
+	master->cleanup = atmel_spi_cleanup;
+	master->auto_runtime_pm = true;
+	platform_set_drvdata(pdev, master);
+
+	as = spi_master_get_devdata(master);
+
+	/*
+	 * Scratch buffer is used for throwaway rx and tx data.
+	 * It's coherent to minimize dcache pollution.
+	 */
+	as->buffer = dma_alloc_coherent(&pdev->dev, BUFFER_SIZE,
+					&as->buffer_dma, GFP_KERNEL);
+	if (!as->buffer)
+		goto out_free;
+
+	spin_lock_init(&as->lock);
+
+	as->pdev = pdev;
+	as->regs = devm_ioremap_resource(&pdev->dev, regs);
+	if (IS_ERR(as->regs)) {
+		ret = PTR_ERR(as->regs);
+		goto out_free_buffer;
+	}
+	as->phybase = regs->start;
+	as->irq = irq;
+	as->clk = clk;
+
+	init_completion(&as->xfer_completion);
+
+	atmel_get_caps(as);
+
+	as->use_dma = false;
+	as->use_pdc = false;
+	if (as->caps.has_dma_support) {
+		ret = atmel_spi_configure_dma(as);
+		if (ret == 0)
+			as->use_dma = true;
+		else if (ret == -EPROBE_DEFER)
+			return ret;
+	} else {
+		as->use_pdc = true;
+	}
+
+	if (as->caps.has_dma_support && !as->use_dma)
+		dev_info(&pdev->dev, "Atmel SPI Controller using PIO only\n");
+
+	if (as->use_pdc) {
+		ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pdc_interrupt,
+					0, dev_name(&pdev->dev), master);
+	} else {
+		ret = devm_request_irq(&pdev->dev, irq, atmel_spi_pio_interrupt,
+					0, dev_name(&pdev->dev), master);
+	}
+	if (ret)
+		goto out_unmap_regs;
+
+	/* Initialize the hardware */
+	ret = clk_prepare_enable(clk);
+	if (ret)
+		goto out_free_irq;
+	spi_writel(as, CR, SPI_BIT(SWRST));
+	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
+	if (as->caps.has_wdrbt) {
+		spi_writel(as, MR, SPI_BIT(WDRBT) | SPI_BIT(MODFDIS)
+				| SPI_BIT(MSTR));
+	} else {
+		spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
+	}
+
+	if (as->use_pdc)
+		spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
+	spi_writel(as, CR, SPI_BIT(SPIEN));
+
+	/* go! */
+	dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n",
+			(unsigned long)regs->start, irq);
+
+	pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	ret = devm_spi_register_master(&pdev->dev, master);
+	if (ret)
+		goto out_free_dma;
+
+	return 0;
+
+out_free_dma:
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+
+	if (as->use_dma)
+		atmel_spi_release_dma(as);
+
+	spi_writel(as, CR, SPI_BIT(SWRST));
+	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
+	clk_disable_unprepare(clk);
+out_free_irq:
+out_unmap_regs:
+out_free_buffer:
+	dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
+			as->buffer_dma);
+out_free:
+	spi_master_put(master);
+	return ret;
+}
+
+static int atmel_spi_remove(struct platform_device *pdev)
+{
+	struct spi_master	*master = platform_get_drvdata(pdev);
+	struct atmel_spi	*as = spi_master_get_devdata(master);
+
+	pm_runtime_get_sync(&pdev->dev);
+
+	/* reset the hardware and block queue progress */
+	spin_lock_irq(&as->lock);
+	if (as->use_dma) {
+		atmel_spi_stop_dma(as);
+		atmel_spi_release_dma(as);
+	}
+
+	spi_writel(as, CR, SPI_BIT(SWRST));
+	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
+	spi_readl(as, SR);
+	spin_unlock_irq(&as->lock);
+
+	dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
+			as->buffer_dma);
+
+	clk_disable_unprepare(as->clk);
+
+	pm_runtime_put_noidle(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int atmel_spi_runtime_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct atmel_spi *as = spi_master_get_devdata(master);
+
+	clk_disable_unprepare(as->clk);
+	pinctrl_pm_select_sleep_state(dev);
+
+	return 0;
+}
+
+static int atmel_spi_runtime_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct atmel_spi *as = spi_master_get_devdata(master);
+
+	pinctrl_pm_select_default_state(dev);
+
+	return clk_prepare_enable(as->clk);
+}
+
+static int atmel_spi_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	int ret;
+
+	/* Stop the queue running */
+	ret = spi_master_suspend(master);
+	if (ret) {
+		dev_warn(dev, "cannot suspend master\n");
+		return ret;
+	}
+
+	if (!pm_runtime_suspended(dev))
+		atmel_spi_runtime_suspend(dev);
+
+	return 0;
+}
+
+static int atmel_spi_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	int ret;
+
+	if (!pm_runtime_suspended(dev)) {
+		ret = atmel_spi_runtime_resume(dev);
+		if (ret)
+			return ret;
+	}
+
+	/* Start the queue running */
+	ret = spi_master_resume(master);
+	if (ret)
+		dev_err(dev, "problem starting queue (%d)\n", ret);
+
+	return ret;
+}
+
+static const struct dev_pm_ops atmel_spi_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(atmel_spi_suspend, atmel_spi_resume)
+	SET_RUNTIME_PM_OPS(atmel_spi_runtime_suspend,
+			   atmel_spi_runtime_resume, NULL)
+};
+#define ATMEL_SPI_PM_OPS	(&atmel_spi_pm_ops)
+#else
+#define ATMEL_SPI_PM_OPS	NULL
+#endif
+
+#if defined(CONFIG_OF)
+static const struct of_device_id atmel_spi_dt_ids[] = {
+	{ .compatible = "atmel,at91rm9200-spi" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, atmel_spi_dt_ids);
+#endif
+
+static struct platform_driver atmel_spi_driver = {
+	.driver		= {
+		.name	= "atmel_spi",
+		.pm	= ATMEL_SPI_PM_OPS,
+		.of_match_table	= of_match_ptr(atmel_spi_dt_ids),
+	},
+	.probe		= atmel_spi_probe,
+	.remove		= atmel_spi_remove,
+};
+module_platform_driver(atmel_spi_driver);
+
+MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
+MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:atmel_spi");