spi-atmel.c 27.9 KB
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/*
 * 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/init.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/err.h>
#include <linux/interrupt.h>
#include <linux/spi/spi.h>
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#include <linux/slab.h>
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#include <linux/platform_data/atmel.h>
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#include <linux/of.h>
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#include <asm/io.h>
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#include <asm/gpio.h>
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#include <mach/cpu.h>
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/* 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_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_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 */
#define spi_readl(port,reg) \
	__raw_readl((port)->regs + SPI_##reg)
#define spi_writel(port,reg,value) \
	__raw_writel((value), (port)->regs + SPI_##reg)

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/*
 * 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;

	void __iomem		*regs;
	int			irq;
	struct clk		*clk;
	struct platform_device	*pdev;
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	struct spi_device	*stay;
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	u8			stopping;
	struct list_head	queue;
	struct spi_transfer	*current_transfer;
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	unsigned long		current_remaining_bytes;
	struct spi_transfer	*next_transfer;
	unsigned long		next_remaining_bytes;
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	void			*buffer;
	dma_addr_t		buffer_dma;
};

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/* Controller-specific per-slave state */
struct atmel_spi_device {
	unsigned int		npcs_pin;
	u32			csr;
};

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#define BUFFER_SIZE		PAGE_SIZE
#define INVALID_DMA_ADDRESS	0xffffffff

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/*
 * 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
 *
 * We can determine the controller version by reading the VERSION
 * register, but I haven't checked that it exists on all chips, and
 * this is cheaper anyway.
 */
static bool atmel_spi_is_v2(void)
{
	return !cpu_is_at91rm9200();
}

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/*
 * 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
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 * 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.
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 *
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 * 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.
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 *
 * TODO: Test if the atmel_spi_is_v2() branch below works on
 * AT91RM9200 if we use some other register than CSR0. However, don't
 * do this unconditionally since AP7000 has an errata where the BITS
 * field in CSR0 overrides all other CSRs.
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 */

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static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
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{
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	struct atmel_spi_device *asd = spi->controller_state;
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	unsigned active = spi->mode & SPI_CS_HIGH;
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	u32 mr;

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	if (atmel_spi_is_v2()) {
		/*
		 * Always use CSR0. This ensures that the clock
		 * switches to the correct idle polarity before we
		 * toggle the CS.
		 */
		spi_writel(as, CSR0, asd->csr);
		spi_writel(as, MR, SPI_BF(PCS, 0x0e) | 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);
	}
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	dev_dbg(&spi->dev, "activate %u%s, mr %08x\n",
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			asd->npcs_pin, active ? " (high)" : "",
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			mr);
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}

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static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
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{
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	struct atmel_spi_device *asd = spi->controller_state;
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	unsigned active = spi->mode & SPI_CS_HIGH;
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	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);
	}
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	dev_dbg(&spi->dev, "DEactivate %u%s, mr %08x\n",
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			asd->npcs_pin, active ? " (low)" : "",
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			mr);

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	if (atmel_spi_is_v2() || spi->chip_select != 0)
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		gpio_set_value(asd->npcs_pin, !active);
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}

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static inline int atmel_spi_xfer_is_last(struct spi_message *msg,
					struct spi_transfer *xfer)
{
	return msg->transfers.prev == &xfer->transfer_list;
}

static inline int atmel_spi_xfer_can_be_chained(struct spi_transfer *xfer)
{
	return xfer->delay_usecs == 0 && !xfer->cs_change;
}

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)
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		*rx_dma = xfer->rx_dma + xfer->len - *plen;
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	else {
		*rx_dma = as->buffer_dma;
		if (len > BUFFER_SIZE)
			len = BUFFER_SIZE;
	}
	if (xfer->tx_buf)
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		*tx_dma = xfer->tx_dma + xfer->len - *plen;
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	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;
}

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/*
 * Submit next transfer for DMA.
 * lock is held, spi irq is blocked
 */
static void atmel_spi_next_xfer(struct spi_master *master,
				struct spi_message *msg)
{
	struct atmel_spi	*as = spi_master_get_devdata(master);
	struct spi_transfer	*xfer;
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	u32			len, remaining;
	u32			ieval;
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	dma_addr_t		tx_dma, rx_dma;

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	if (!as->current_transfer)
		xfer = list_entry(msg->transfers.next,
				struct spi_transfer, transfer_list);
	else if (!as->next_transfer)
		xfer = list_entry(as->current_transfer->transfer_list.next,
				struct spi_transfer, transfer_list);
	else
		xfer = NULL;

	if (xfer) {
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		spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));

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		len = xfer->len;
		atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
		remaining = xfer->len - 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);
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		dev_dbg(&msg->spi->dev,
			"  start xfer %p: len %u tx %p/%08x rx %p/%08x\n",
			xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
			xfer->rx_buf, xfer->rx_dma);
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	} else {
		xfer = as->next_transfer;
		remaining = as->next_remaining_bytes;
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	}

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	as->current_transfer = xfer;
	as->current_remaining_bytes = remaining;
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	if (remaining > 0)
		len = remaining;
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	else if (!atmel_spi_xfer_is_last(msg, xfer)
			&& atmel_spi_xfer_can_be_chained(xfer)) {
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		xfer = list_entry(xfer->transfer_list.next,
				struct spi_transfer, transfer_list);
		len = xfer->len;
	} else
		xfer = NULL;
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	as->next_transfer = xfer;
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	if (xfer) {
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		u32	total;

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		total = len;
		atmel_spi_next_xfer_data(master, xfer, &tx_dma, &rx_dma, &len);
		as->next_remaining_bytes = total - len;
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		spi_writel(as, RNPR, rx_dma);
		spi_writel(as, TNPR, tx_dma);
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		if (msg->spi->bits_per_word > 8)
			len >>= 1;
		spi_writel(as, RNCR, len);
		spi_writel(as, TNCR, len);
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		dev_dbg(&msg->spi->dev,
			"  next xfer %p: len %u tx %p/%08x rx %p/%08x\n",
			xfer, xfer->len, xfer->tx_buf, xfer->tx_dma,
			xfer->rx_buf, xfer->rx_dma);
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		ieval = SPI_BIT(ENDRX) | SPI_BIT(OVRES);
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	} else {
		spi_writel(as, RNCR, 0);
		spi_writel(as, TNCR, 0);
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		ieval = SPI_BIT(RXBUFF) | SPI_BIT(ENDRX) | SPI_BIT(OVRES);
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	}

	/* REVISIT: We're waiting for ENDRX before we start the next
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	 * transfer because we need to handle some difficult timing
	 * issues otherwise. If we wait for ENDTX in one transfer and
	 * then starts waiting for ENDRX in the next, it's difficult
	 * to tell the difference between the ENDRX interrupt we're
	 * actually waiting for and the ENDRX interrupt of the
	 * previous transfer.
	 *
	 * It should be doable, though. Just not now...
	 */
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	spi_writel(as, IER, ieval);
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	spi_writel(as, PTCR, SPI_BIT(TXTEN) | SPI_BIT(RXTEN));
}

static void atmel_spi_next_message(struct spi_master *master)
{
	struct atmel_spi	*as = spi_master_get_devdata(master);
	struct spi_message	*msg;
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	struct spi_device	*spi;
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	BUG_ON(as->current_transfer);

	msg = list_entry(as->queue.next, struct spi_message, queue);
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	spi = msg->spi;
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	dev_dbg(master->dev.parent, "start message %p for %s\n",
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			msg, dev_name(&spi->dev));
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	/* select chip if it's not still active */
	if (as->stay) {
		if (as->stay != spi) {
			cs_deactivate(as, as->stay);
			cs_activate(as, spi);
		}
		as->stay = NULL;
	} else
		cs_activate(as, spi);
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	atmel_spi_next_xfer(master, msg);
}

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/*
 * 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
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 *  - If the buffer is valid, so is its DMA address
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 *
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 * This driver manages the dma address unless message->is_dma_mapped.
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 */
static int
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atmel_spi_dma_map_xfer(struct atmel_spi *as, struct spi_transfer *xfer)
{
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	struct device	*dev = &as->pdev->dev;

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	xfer->tx_dma = xfer->rx_dma = INVALID_DMA_ADDRESS;
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	if (xfer->tx_buf) {
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		/* tx_buf is a const void* where we need a void * for the dma
		 * mapping */
		void *nonconst_tx = (void *)xfer->tx_buf;

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		xfer->tx_dma = dma_map_single(dev,
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				nonconst_tx, xfer->len,
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				DMA_TO_DEVICE);
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		if (dma_mapping_error(dev, xfer->tx_dma))
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			return -ENOMEM;
	}
	if (xfer->rx_buf) {
		xfer->rx_dma = dma_map_single(dev,
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				xfer->rx_buf, xfer->len,
				DMA_FROM_DEVICE);
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		if (dma_mapping_error(dev, xfer->rx_dma)) {
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			if (xfer->tx_buf)
				dma_unmap_single(dev,
						xfer->tx_dma, xfer->len,
						DMA_TO_DEVICE);
			return -ENOMEM;
		}
	}
	return 0;
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}

static void atmel_spi_dma_unmap_xfer(struct spi_master *master,
				     struct spi_transfer *xfer)
{
	if (xfer->tx_dma != INVALID_DMA_ADDRESS)
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		dma_unmap_single(master->dev.parent, xfer->tx_dma,
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				 xfer->len, DMA_TO_DEVICE);
	if (xfer->rx_dma != INVALID_DMA_ADDRESS)
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		dma_unmap_single(master->dev.parent, xfer->rx_dma,
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				 xfer->len, DMA_FROM_DEVICE);
}

static void
atmel_spi_msg_done(struct spi_master *master, struct atmel_spi *as,
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		struct spi_message *msg, int status, int stay)
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{
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	if (!stay || status < 0)
		cs_deactivate(as, msg->spi);
	else
		as->stay = msg->spi;

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	list_del(&msg->queue);
	msg->status = status;

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	dev_dbg(master->dev.parent,
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		"xfer complete: %u bytes transferred\n",
		msg->actual_length);

	spin_unlock(&as->lock);
	msg->complete(msg->context);
	spin_lock(&as->lock);

	as->current_transfer = NULL;
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	as->next_transfer = NULL;
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	/* continue if needed */
	if (list_empty(&as->queue) || as->stopping)
		spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
	else
		atmel_spi_next_message(master);
}

static irqreturn_t
atmel_spi_interrupt(int irq, void *dev_id)
{
	struct spi_master	*master = dev_id;
	struct atmel_spi	*as = spi_master_get_devdata(master);
	struct spi_message	*msg;
	struct spi_transfer	*xfer;
	u32			status, pending, imr;
	int			ret = IRQ_NONE;

	spin_lock(&as->lock);

	xfer = as->current_transfer;
	msg = list_entry(as->queue.next, struct spi_message, queue);

	imr = spi_readl(as, IMR);
	status = spi_readl(as, SR);
	pending = status & imr;

	if (pending & SPI_BIT(OVRES)) {
		int timeout;

		ret = IRQ_HANDLED;

599
		spi_writel(as, IDR, (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX)
600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620
				     | SPI_BIT(OVRES)));

		/*
		 * 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.
		 *
		 * First, stop the transfer and unmap the DMA buffers.
		 */
		spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS));
		if (!msg->is_dma_mapped)
			atmel_spi_dma_unmap_xfer(master, xfer);

		/* REVISIT: udelay in irq is unfriendly */
		if (xfer->delay_usecs)
			udelay(xfer->delay_usecs);

621
		dev_warn(master->dev.parent, "overrun (%u/%u remaining)\n",
622 623 624 625 626 627 628 629 630 631 632 633 634 635
			 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)
T
Tony Jones 已提交
636
			dev_warn(master->dev.parent,
637 638 639 640 641 642 643
				 "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);

644
		atmel_spi_msg_done(master, as, msg, -EIO, 0);
645
	} else if (pending & (SPI_BIT(RXBUFF) | SPI_BIT(ENDRX))) {
646 647 648 649
		ret = IRQ_HANDLED;

		spi_writel(as, IDR, pending);

S
Silvester Erdeg 已提交
650
		if (as->current_remaining_bytes == 0) {
651 652 653 654 655 656 657 658 659
			msg->actual_length += xfer->len;

			if (!msg->is_dma_mapped)
				atmel_spi_dma_unmap_xfer(master, xfer);

			/* REVISIT: udelay in irq is unfriendly */
			if (xfer->delay_usecs)
				udelay(xfer->delay_usecs);

S
Silvester Erdeg 已提交
660
			if (atmel_spi_xfer_is_last(msg, xfer)) {
661
				/* report completed message */
662 663
				atmel_spi_msg_done(master, as, msg, 0,
						xfer->cs_change);
664 665
			} else {
				if (xfer->cs_change) {
666
					cs_deactivate(as, msg->spi);
667
					udelay(1);
668
					cs_activate(as, msg->spi);
669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694
				}

				/*
				 * Not done yet. Submit the next transfer.
				 *
				 * FIXME handle protocol options for xfer
				 */
				atmel_spi_next_xfer(master, msg);
			}
		} else {
			/*
			 * Keep going, we still have data to send in
			 * the current transfer.
			 */
			atmel_spi_next_xfer(master, msg);
		}
	}

	spin_unlock(&as->lock);

	return ret;
}

static int atmel_spi_setup(struct spi_device *spi)
{
	struct atmel_spi	*as;
695
	struct atmel_spi_device	*asd;
696 697
	u32			scbr, csr;
	unsigned int		bits = spi->bits_per_word;
698
	unsigned long		bus_hz;
699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720
	unsigned int		npcs_pin;
	int			ret;

	as = spi_master_get_devdata(spi->master);

	if (as->stopping)
		return -ESHUTDOWN;

	if (spi->chip_select > spi->master->num_chipselect) {
		dev_dbg(&spi->dev,
				"setup: invalid chipselect %u (%u defined)\n",
				spi->chip_select, spi->master->num_chipselect);
		return -EINVAL;
	}

	if (bits < 8 || bits > 16) {
		dev_dbg(&spi->dev,
				"setup: invalid bits_per_word %u (8 to 16)\n",
				bits);
		return -EINVAL;
	}

721
	/* see notes above re chipselect */
722
	if (!atmel_spi_is_v2()
723 724 725 726 727 728
			&& spi->chip_select == 0
			&& (spi->mode & SPI_CS_HIGH)) {
		dev_dbg(&spi->dev, "setup: can't be active-high\n");
		return -EINVAL;
	}

729
	/* v1 chips start out at half the peripheral bus speed. */
730
	bus_hz = clk_get_rate(as->clk);
731
	if (!atmel_spi_is_v2())
732 733
		bus_hz /= 2;

734
	if (spi->max_speed_hz) {
735 736 737 738 739 740 741 742 743 744
		/*
		 * Calculate the lowest divider that satisfies the
		 * constraint, assuming div32/fdiv/mbz == 0.
		 */
		scbr = DIV_ROUND_UP(bus_hz, spi->max_speed_hz);

		/*
		 * If the resulting divider doesn't fit into the
		 * register bitfield, we can't satisfy the constraint.
		 */
745
		if (scbr >= (1 << SPI_SCBR_SIZE)) {
D
David Brownell 已提交
746 747 748
			dev_dbg(&spi->dev,
				"setup: %d Hz too slow, scbr %u; min %ld Hz\n",
				spi->max_speed_hz, scbr, bus_hz/255);
749 750 751
			return -EINVAL;
		}
	} else
752
		/* speed zero means "as slow as possible" */
753 754 755 756 757 758 759 760
		scbr = 0xff;

	csr = SPI_BF(SCBR, scbr) | SPI_BF(BITS, bits - 8);
	if (spi->mode & SPI_CPOL)
		csr |= SPI_BIT(CPOL);
	if (!(spi->mode & SPI_CPHA))
		csr |= SPI_BIT(NCPHA);

761 762 763 764 765 766 767 768
	/* 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);
769 770 771

	/* chipselect must have been muxed as GPIO (e.g. in board setup) */
	npcs_pin = (unsigned int)spi->controller_data;
772 773 774 775

	if (gpio_is_valid(spi->cs_gpio))
		npcs_pin = spi->cs_gpio;

776 777 778 779 780 781
	asd = spi->controller_state;
	if (!asd) {
		asd = kzalloc(sizeof(struct atmel_spi_device), GFP_KERNEL);
		if (!asd)
			return -ENOMEM;

782
		ret = gpio_request(npcs_pin, dev_name(&spi->dev));
783 784
		if (ret) {
			kfree(asd);
785
			return ret;
786 787 788 789
		}

		asd->npcs_pin = npcs_pin;
		spi->controller_state = asd;
790
		gpio_direction_output(npcs_pin, !(spi->mode & SPI_CS_HIGH));
791 792 793 794 795 796 797 798
	} else {
		unsigned long		flags;

		spin_lock_irqsave(&as->lock, flags);
		if (as->stay == spi)
			as->stay = NULL;
		cs_deactivate(as, spi);
		spin_unlock_irqrestore(&as->lock, flags);
799 800
	}

801 802
	asd->csr = csr;

803 804
	dev_dbg(&spi->dev,
		"setup: %lu Hz bpw %u mode 0x%x -> csr%d %08x\n",
805
		bus_hz / scbr, bits, spi->mode, spi->chip_select, csr);
806

807 808
	if (!atmel_spi_is_v2())
		spi_writel(as, CSR0 + 4 * spi->chip_select, csr);
809 810 811 812 813 814 815 816 817

	return 0;
}

static int atmel_spi_transfer(struct spi_device *spi, struct spi_message *msg)
{
	struct atmel_spi	*as;
	struct spi_transfer	*xfer;
	unsigned long		flags;
T
Tony Jones 已提交
818
	struct device		*controller = spi->master->dev.parent;
819 820
	u8			bits;
	struct atmel_spi_device	*asd;
821 822 823 824

	as = spi_master_get_devdata(spi->master);

	dev_dbg(controller, "new message %p submitted for %s\n",
825
			msg, dev_name(&spi->dev));
826

827
	if (unlikely(list_empty(&msg->transfers)))
828 829 830 831 832 833
		return -EINVAL;

	if (as->stopping)
		return -ESHUTDOWN;

	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
834
		if (!(xfer->tx_buf || xfer->rx_buf) && xfer->len) {
835 836 837 838
			dev_dbg(&spi->dev, "missing rx or tx buf\n");
			return -EINVAL;
		}

839 840 841 842 843
		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 "
844
					 "bits_per_word in transfers\n");
845 846 847 848
				return -ENOPROTOOPT;
			}
		}

849
		/* FIXME implement these protocol options!! */
850
		if (xfer->speed_hz) {
851 852 853 854
			dev_dbg(&spi->dev, "no protocol options yet\n");
			return -ENOPROTOOPT;
		}

D
David Brownell 已提交
855 856 857 858 859 860 861 862 863 864 865 866
		/*
		 * DMA map early, for performance (empties dcache ASAP) and
		 * better fault reporting.  This is a DMA-only driver.
		 *
		 * NOTE that if dma_unmap_single() ever starts to do work on
		 * platforms supported by this driver, we would need to clean
		 * up mappings for previously-mapped transfers.
		 */
		if (!msg->is_dma_mapped) {
			if (atmel_spi_dma_map_xfer(as, xfer) < 0)
				return -ENOMEM;
		}
867 868
	}

869
#ifdef VERBOSE
870 871 872 873 874 875 876
	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
		dev_dbg(controller,
			"  xfer %p: len %u tx %p/%08x rx %p/%08x\n",
			xfer, xfer->len,
			xfer->tx_buf, xfer->tx_dma,
			xfer->rx_buf, xfer->rx_dma);
	}
877
#endif
878 879 880 881 882 883 884 885 886 887 888 889 890

	msg->status = -EINPROGRESS;
	msg->actual_length = 0;

	spin_lock_irqsave(&as->lock, flags);
	list_add_tail(&msg->queue, &as->queue);
	if (!as->current_transfer)
		atmel_spi_next_message(spi->master);
	spin_unlock_irqrestore(&as->lock, flags);

	return 0;
}

891
static void atmel_spi_cleanup(struct spi_device *spi)
892
{
893
	struct atmel_spi	*as = spi_master_get_devdata(spi->master);
894
	struct atmel_spi_device	*asd = spi->controller_state;
895 896 897
	unsigned		gpio = (unsigned) spi->controller_data;
	unsigned long		flags;

898
	if (!asd)
899 900 901 902 903 904 905 906 907
		return;

	spin_lock_irqsave(&as->lock, flags);
	if (as->stay == spi) {
		as->stay = NULL;
		cs_deactivate(as, spi);
	}
	spin_unlock_irqrestore(&as->lock, flags);

908
	spi->controller_state = NULL;
909
	gpio_free(gpio);
910
	kfree(asd);
911 912 913 914
}

/*-------------------------------------------------------------------------*/

915
static int atmel_spi_probe(struct platform_device *pdev)
916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941
{
	struct resource		*regs;
	int			irq;
	struct clk		*clk;
	int			ret;
	struct spi_master	*master;
	struct atmel_spi	*as;

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!regs)
		return -ENXIO;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	clk = 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;

942 943 944
	/* the spi->mode bits understood by this driver: */
	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;

945
	master->dev.of_node = pdev->dev.of_node;
946
	master->bus_num = pdev->id;
947
	master->num_chipselect = master->dev.of_node ? 0 : 4;
948 949 950 951 952 953 954
	master->setup = atmel_spi_setup;
	master->transfer = atmel_spi_transfer;
	master->cleanup = atmel_spi_cleanup;
	platform_set_drvdata(pdev, master);

	as = spi_master_get_devdata(master);

D
David Brownell 已提交
955 956 957 958
	/*
	 * Scratch buffer is used for throwaway rx and tx data.
	 * It's coherent to minimize dcache pollution.
	 */
959 960 961 962 963 964 965 966
	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);
	INIT_LIST_HEAD(&as->queue);
	as->pdev = pdev;
H
hartleys 已提交
967
	as->regs = ioremap(regs->start, resource_size(regs));
968 969 970 971 972 973
	if (!as->regs)
		goto out_free_buffer;
	as->irq = irq;
	as->clk = clk;

	ret = request_irq(irq, atmel_spi_interrupt, 0,
974
			dev_name(&pdev->dev), master);
975 976 977 978 979 980
	if (ret)
		goto out_unmap_regs;

	/* Initialize the hardware */
	clk_enable(clk);
	spi_writel(as, CR, SPI_BIT(SWRST));
981
	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997
	spi_writel(as, MR, SPI_BIT(MSTR) | SPI_BIT(MODFDIS));
	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);

	ret = spi_register_master(master);
	if (ret)
		goto out_reset_hw;

	return 0;

out_reset_hw:
	spi_writel(as, CR, SPI_BIT(SWRST));
998
	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011
	clk_disable(clk);
	free_irq(irq, master);
out_unmap_regs:
	iounmap(as->regs);
out_free_buffer:
	dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
			as->buffer_dma);
out_free:
	clk_put(clk);
	spi_master_put(master);
	return ret;
}

1012
static int atmel_spi_remove(struct platform_device *pdev)
1013 1014 1015 1016 1017 1018 1019 1020 1021
{
	struct spi_master	*master = platform_get_drvdata(pdev);
	struct atmel_spi	*as = spi_master_get_devdata(master);
	struct spi_message	*msg;

	/* reset the hardware and block queue progress */
	spin_lock_irq(&as->lock);
	as->stopping = 1;
	spi_writel(as, CR, SPI_BIT(SWRST));
1022
	spi_writel(as, CR, SPI_BIT(SWRST)); /* AT91SAM9263 Rev B workaround */
1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072
	spi_readl(as, SR);
	spin_unlock_irq(&as->lock);

	/* Terminate remaining queued transfers */
	list_for_each_entry(msg, &as->queue, queue) {
		/* REVISIT unmapping the dma is a NOP on ARM and AVR32
		 * but we shouldn't depend on that...
		 */
		msg->status = -ESHUTDOWN;
		msg->complete(msg->context);
	}

	dma_free_coherent(&pdev->dev, BUFFER_SIZE, as->buffer,
			as->buffer_dma);

	clk_disable(as->clk);
	clk_put(as->clk);
	free_irq(as->irq, master);
	iounmap(as->regs);

	spi_unregister_master(master);

	return 0;
}

#ifdef	CONFIG_PM

static int atmel_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
{
	struct spi_master	*master = platform_get_drvdata(pdev);
	struct atmel_spi	*as = spi_master_get_devdata(master);

	clk_disable(as->clk);
	return 0;
}

static int atmel_spi_resume(struct platform_device *pdev)
{
	struct spi_master	*master = platform_get_drvdata(pdev);
	struct atmel_spi	*as = spi_master_get_devdata(master);

	clk_enable(as->clk);
	return 0;
}

#else
#define	atmel_spi_suspend	NULL
#define	atmel_spi_resume	NULL
#endif

1073 1074 1075 1076 1077 1078 1079 1080
#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
1081 1082 1083 1084 1085

static struct platform_driver atmel_spi_driver = {
	.driver		= {
		.name	= "atmel_spi",
		.owner	= THIS_MODULE,
1086
		.of_match_table	= of_match_ptr(atmel_spi_dt_ids),
1087 1088 1089
	},
	.suspend	= atmel_spi_suspend,
	.resume		= atmel_spi_resume,
1090
	.probe		= atmel_spi_probe,
1091
	.remove		= atmel_spi_remove,
1092
};
1093
module_platform_driver(atmel_spi_driver);
1094 1095

MODULE_DESCRIPTION("Atmel AT32/AT91 SPI Controller driver");
J
Jean Delvare 已提交
1096
MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
1097
MODULE_LICENSE("GPL");
1098
MODULE_ALIAS("platform:atmel_spi");