Merge branch 'next-spi' of git://git.secretlab.ca/git/linux-2.6

* 'next-spi' of git://git.secretlab.ca/git/linux-2.6:
  spi/amba_pl022: Fix probe and remove hook section annotations.
  spi/mpc5121: change annotations for probe and remove functions
  spi/bitbang: reinitialize transfer parameters for every message
  spi/spi-gpio: add support for controllers without MISO or MOSI pin
  spi/bitbang: add support for SPI_MASTER_NO_{TX, RX} modes
  SPI100k: Fix 8-bit and RX-only transfers
  spi/mmc_spi: mmc_spi adaptations for SPI bus locking API
  spi/mmc_spi: SPI bus locking API, using mutex

Fix trivial conflict in drivers/spi/mpc512x_psc_spi.c due to 'struct
of_device' => 'struct platform_device' rename and __init/__exit to
__devinit/__devexit fix.

drivers/mmc/host/mmc_spi.c

@@ -182,7 +182,7 @@ mmc_spi_readbytes(struct mmc_spi_host *host, unsigned len)
 				host->data_dma, sizeof(*host->data),
 				DMA_FROM_DEVICE);
 
-	status = spi_sync(host->spi, &host->readback);
+	status = spi_sync_locked(host->spi, &host->readback);
 
 	if (host->dma_dev)
 		dma_sync_single_for_cpu(host->dma_dev,
@@ -541,7 +541,7 @@ mmc_spi_command_send(struct mmc_spi_host *host,
 				host->data_dma, sizeof(*host->data),
 				DMA_BIDIRECTIONAL);
 	}
-	status = spi_sync(host->spi, &host->m);
+	status = spi_sync_locked(host->spi, &host->m);
 
 	if (host->dma_dev)
 		dma_sync_single_for_cpu(host->dma_dev,
@@ -685,7 +685,7 @@ mmc_spi_writeblock(struct mmc_spi_host *host, struct spi_transfer *t,
 				host->data_dma, sizeof(*scratch),
 				DMA_BIDIRECTIONAL);
 
-	status = spi_sync(spi, &host->m);
+	status = spi_sync_locked(spi, &host->m);
 
 	if (status != 0) {
 		dev_dbg(&spi->dev, "write error (%d)\n", status);
@@ -822,7 +822,7 @@ mmc_spi_readblock(struct mmc_spi_host *host, struct spi_transfer *t,
 				DMA_FROM_DEVICE);
 	}
 
-	status = spi_sync(spi, &host->m);
+	status = spi_sync_locked(spi, &host->m);
 
 	if (host->dma_dev) {
 		dma_sync_single_for_cpu(host->dma_dev,
@@ -1018,7 +1018,7 @@ mmc_spi_data_do(struct mmc_spi_host *host, struct mmc_command *cmd,
 					host->data_dma, sizeof(*scratch),
 					DMA_BIDIRECTIONAL);
 
-		tmp = spi_sync(spi, &host->m);
+		tmp = spi_sync_locked(spi, &host->m);
 
 		if (host->dma_dev)
 			dma_sync_single_for_cpu(host->dma_dev,
@@ -1084,6 +1084,9 @@ static void mmc_spi_request(struct mmc_host *mmc, struct mmc_request *mrq)
 	}
 #endif
 
+	/* request exclusive bus access */
+	spi_bus_lock(host->spi->master);
+
 	/* issue command; then optionally data and stop */
 	status = mmc_spi_command_send(host, mrq, mrq->cmd, mrq->data != NULL);
 	if (status == 0 && mrq->data) {
@@ -1094,6 +1097,9 @@ static void mmc_spi_request(struct mmc_host *mmc, struct mmc_request *mrq)
 			mmc_cs_off(host);
 	}
 
+	/* release the bus */
+	spi_bus_unlock(host->spi->master);
+
 	mmc_request_done(host->mmc, mrq);
 }
 
@@ -1290,23 +1296,6 @@ mmc_spi_detect_irq(int irq, void *mmc)
 	return IRQ_HANDLED;
 }
 
-struct count_children {
-	unsigned	n;
-	struct bus_type	*bus;
-};
-
-static int maybe_count_child(struct device *dev, void *c)
-{
-	struct count_children *ccp = c;
-
-	if (dev->bus == ccp->bus) {
-		if (ccp->n)
-			return -EBUSY;
-		ccp->n++;
-	}
-	return 0;
-}
-
 static int mmc_spi_probe(struct spi_device *spi)
 {
 	void			*ones;
@@ -1338,32 +1327,6 @@ static int mmc_spi_probe(struct spi_device *spi)
 		return status;
 	}
 
-	/* We can use the bus safely iff nobody else will interfere with us.
-	 * Most commands consist of one SPI message to issue a command, then
-	 * several more to collect its response, then possibly more for data
-	 * transfer.  Clocking access to other devices during that period will
-	 * corrupt the command execution.
-	 *
-	 * Until we have software primitives which guarantee non-interference,
-	 * we'll aim for a hardware-level guarantee.
-	 *
-	 * REVISIT we can't guarantee another device won't be added later...
-	 */
-	if (spi->master->num_chipselect > 1) {
-		struct count_children cc;
-
-		cc.n = 0;
-		cc.bus = spi->dev.bus;
-		status = device_for_each_child(spi->dev.parent, &cc,
-				maybe_count_child);
-		if (status < 0) {
-			dev_err(&spi->dev, "can't share SPI bus\n");
-			return status;
-		}
-
-		dev_warn(&spi->dev, "ASSUMING SPI bus stays unshared!\n");
-	}
-
 	/* We need a supply of ones to transmit.  This is the only time
 	 * the CPU touches these, so cache coherency isn't a concern.
 	 *

drivers/spi/amba-pl022.c

@@ -1723,7 +1723,7 @@ static void pl022_cleanup(struct spi_device *spi)
 }
 
 
-static int __init
+static int __devinit
 pl022_probe(struct amba_device *adev, struct amba_id *id)
 {
 	struct device *dev = &adev->dev;
@@ -1838,7 +1838,7 @@ pl022_probe(struct amba_device *adev, struct amba_id *id)
 	return status;
 }
 
-static int __exit
+static int __devexit
 pl022_remove(struct amba_device *adev)
 {
 	struct pl022 *pl022 = amba_get_drvdata(adev);
@@ -1970,7 +1970,7 @@ static struct amba_driver pl022_driver = {
 	},
 	.id_table	= pl022_ids,
 	.probe		= pl022_probe,
-	.remove		= __exit_p(pl022_remove),
+	.remove		= __devexit_p(pl022_remove),
 	.suspend        = pl022_suspend,
 	.resume         = pl022_resume,
 };

drivers/spi/mpc512x_psc_spi.c

@@ -406,7 +406,7 @@ static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id)
 }
 
 /* bus_num is used only for the case dev->platform_data == NULL */
-static int __init mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
+static int __devinit mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
 					      u32 size, unsigned int irq,
 					      s16 bus_num)
 {
@@ -492,7 +492,7 @@ static int __init mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
 	return ret;
 }
 
-static int __exit mpc512x_psc_spi_do_remove(struct device *dev)
+static int __devexit mpc512x_psc_spi_do_remove(struct device *dev)
 {
 	struct spi_master *master = dev_get_drvdata(dev);
 	struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
@@ -507,7 +507,7 @@ static int __exit mpc512x_psc_spi_do_remove(struct device *dev)
 	return 0;
 }
 
-static int __init mpc512x_psc_spi_of_probe(struct platform_device *op,
+static int __devinit mpc512x_psc_spi_of_probe(struct platform_device *op,
 					      const struct of_device_id *match)
 {
 	const u32 *regaddr_p;
@@ -539,7 +539,7 @@ static int __init mpc512x_psc_spi_of_probe(struct platform_device *op,
 				irq_of_parse_and_map(op->dev.of_node, 0), id);
 }
 
-static int __exit mpc512x_psc_spi_of_remove(struct platform_device *op)
+static int __devexit mpc512x_psc_spi_of_remove(struct platform_device *op)
 {
 	return mpc512x_psc_spi_do_remove(&op->dev);
 }
@@ -553,7 +553,7 @@ MODULE_DEVICE_TABLE(of, mpc512x_psc_spi_of_match);
 
 static struct of_platform_driver mpc512x_psc_spi_of_driver = {
 	.probe = mpc512x_psc_spi_of_probe,
-	.remove = __exit_p(mpc512x_psc_spi_of_remove),
+	.remove = __devexit_p(mpc512x_psc_spi_of_remove),
 	.driver = {
 		.name = "mpc512x-psc-spi",
 		.owner = THIS_MODULE,

drivers/spi/omap_spi_100k.c

@@ -141,7 +141,12 @@ static void spi100k_write_data(struct spi_master *master, int len, int data)
 {
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 
-	/* write 16-bit word */
+	/* write 16-bit word, shifting 8-bit data if necessary */
+	if (len <= 8) {
+		data <<= 8;
+		len = 16;
+	}
+
 	spi100k_enable_clock(master);
 	writew( data , spi100k->base + SPI_TX_MSB);
 
@@ -162,6 +167,10 @@ static int spi100k_read_data(struct spi_master *master, int len)
 	int dataH,dataL;
 	struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 
+	/* Always do at least 16 bits */
+	if (len <= 8)
+		len = 16;
+
 	spi100k_enable_clock(master);
 	writew(SPI_CTRL_SEN(0) |
 	       SPI_CTRL_WORD_SIZE(len) |
@@ -214,10 +223,6 @@ omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 	c = count;
 	word_len = cs->word_len;
 
-	/* RX_ONLY mode needs dummy data in TX reg */
-	if (xfer->tx_buf == NULL)
-		spi100k_write_data(spi->master,word_len, 0);
-
 	if (word_len <= 8) {
 		u8              *rx;
 		const u8        *tx;
@@ -227,9 +232,9 @@ omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 		do {
 			c-=1;
 			if (xfer->tx_buf != NULL)
-				spi100k_write_data(spi->master,word_len, *tx);
+				spi100k_write_data(spi->master, word_len, *tx++);
 			if (xfer->rx_buf != NULL)
-				*rx = spi100k_read_data(spi->master,word_len);
+				*rx++ = spi100k_read_data(spi->master, word_len);
 		} while(c);
 	} else if (word_len <= 16) {
 		u16             *rx;
@@ -380,10 +385,6 @@ static void omap1_spi100k_work(struct work_struct *work)
 			if (t->len) {
 				unsigned count;
 
-				/* RX_ONLY mode needs dummy data in TX reg */
-				if (t->tx_buf == NULL)
-					spi100k_write_data(spi->master, 8, 0);
-
 				count = omap1_spi100k_txrx_pio(spi, t);
 				m->actual_length += count;
 

drivers/spi/spi.c

@@ -528,6 +528,10 @@ int spi_register_master(struct spi_master *master)
 		dynamic = 1;
 	}
 
+	spin_lock_init(&master->bus_lock_spinlock);
+	mutex_init(&master->bus_lock_mutex);
+	master->bus_lock_flag = 0;
+
 	/* register the device, then userspace will see it.
 	 * registration fails if the bus ID is in use.
 	 */
@@ -670,6 +674,35 @@ int spi_setup(struct spi_device *spi)
 }
 EXPORT_SYMBOL_GPL(spi_setup);
 
+static int __spi_async(struct spi_device *spi, struct spi_message *message)
+{
+	struct spi_master *master = spi->master;
+
+	/* Half-duplex links include original MicroWire, and ones with
+	 * only one data pin like SPI_3WIRE (switches direction) or where
+	 * either MOSI or MISO is missing.  They can also be caused by
+	 * software limitations.
+	 */
+	if ((master->flags & SPI_MASTER_HALF_DUPLEX)
+			|| (spi->mode & SPI_3WIRE)) {
+		struct spi_transfer *xfer;
+		unsigned flags = master->flags;
+
+		list_for_each_entry(xfer, &message->transfers, transfer_list) {
+			if (xfer->rx_buf && xfer->tx_buf)
+				return -EINVAL;
+			if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
+				return -EINVAL;
+			if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
+				return -EINVAL;
+		}
+	}
+
+	message->spi = spi;
+	message->status = -EINPROGRESS;
+	return master->transfer(spi, message);
+}
+
 /**
  * spi_async - asynchronous SPI transfer
  * @spi: device with which data will be exchanged
@@ -702,33 +735,68 @@ EXPORT_SYMBOL_GPL(spi_setup);
 int spi_async(struct spi_device *spi, struct spi_message *message)
 {
 	struct spi_master *master = spi->master;
+	int ret;
+	unsigned long flags;
 
-	/* Half-duplex links include original MicroWire, and ones with
-	 * only one data pin like SPI_3WIRE (switches direction) or where
-	 * either MOSI or MISO is missing.  They can also be caused by
-	 * software limitations.
-	 */
-	if ((master->flags & SPI_MASTER_HALF_DUPLEX)
-			|| (spi->mode & SPI_3WIRE)) {
-		struct spi_transfer *xfer;
-		unsigned flags = master->flags;
+	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
 
-		list_for_each_entry(xfer, &message->transfers, transfer_list) {
-			if (xfer->rx_buf && xfer->tx_buf)
-				return -EINVAL;
-			if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
-				return -EINVAL;
-			if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
-				return -EINVAL;
-		}
-	}
+	if (master->bus_lock_flag)
+		ret = -EBUSY;
+	else
+		ret = __spi_async(spi, message);
 
-	message->spi = spi;
-	message->status = -EINPROGRESS;
-	return master->transfer(spi, message);
+	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(spi_async);
 
+/**
+ * spi_async_locked - version of spi_async with exclusive bus usage
+ * @spi: device with which data will be exchanged
+ * @message: describes the data transfers, including completion callback
+ * Context: any (irqs may be blocked, etc)
+ *
+ * This call may be used in_irq and other contexts which can't sleep,
+ * as well as from task contexts which can sleep.
+ *
+ * The completion callback is invoked in a context which can't sleep.
+ * Before that invocation, the value of message->status is undefined.
+ * When the callback is issued, message->status holds either zero (to
+ * indicate complete success) or a negative error code.  After that
+ * callback returns, the driver which issued the transfer request may
+ * deallocate the associated memory; it's no longer in use by any SPI
+ * core or controller driver code.
+ *
+ * Note that although all messages to a spi_device are handled in
+ * FIFO order, messages may go to different devices in other orders.
+ * Some device might be higher priority, or have various "hard" access
+ * time requirements, for example.
+ *
+ * On detection of any fault during the transfer, processing of
+ * the entire message is aborted, and the device is deselected.
+ * Until returning from the associated message completion callback,
+ * no other spi_message queued to that device will be processed.
+ * (This rule applies equally to all the synchronous transfer calls,
+ * which are wrappers around this core asynchronous primitive.)
+ */
+int spi_async_locked(struct spi_device *spi, struct spi_message *message)
+{
+	struct spi_master *master = spi->master;
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
+
+	ret = __spi_async(spi, message);
+
+	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
+
+	return ret;
+
+}
+EXPORT_SYMBOL_GPL(spi_async_locked);
+
 
 /*-------------------------------------------------------------------------*/
 
@@ -742,6 +810,32 @@ static void spi_complete(void *arg)
 	complete(arg);
 }
 
+static int __spi_sync(struct spi_device *spi, struct spi_message *message,
+		      int bus_locked)
+{
+	DECLARE_COMPLETION_ONSTACK(done);
+	int status;
+	struct spi_master *master = spi->master;
+
+	message->complete = spi_complete;
+	message->context = &done;
+
+	if (!bus_locked)
+		mutex_lock(&master->bus_lock_mutex);
+
+	status = spi_async_locked(spi, message);
+
+	if (!bus_locked)
+		mutex_unlock(&master->bus_lock_mutex);
+
+	if (status == 0) {
+		wait_for_completion(&done);
+		status = message->status;
+	}
+	message->context = NULL;
+	return status;
+}
+
 /**
  * spi_sync - blocking/synchronous SPI data transfers
  * @spi: device with which data will be exchanged
@@ -765,21 +859,86 @@ static void spi_complete(void *arg)
  */
 int spi_sync(struct spi_device *spi, struct spi_message *message)
 {
-	DECLARE_COMPLETION_ONSTACK(done);
-	int status;
-
-	message->complete = spi_complete;
-	message->context = &done;
-	status = spi_async(spi, message);
-	if (status == 0) {
-		wait_for_completion(&done);
-		status = message->status;
-	}
-	message->context = NULL;
-	return status;
+	return __spi_sync(spi, message, 0);
 }
 EXPORT_SYMBOL_GPL(spi_sync);
 
+/**
+ * spi_sync_locked - version of spi_sync with exclusive bus usage
+ * @spi: device with which data will be exchanged
+ * @message: describes the data transfers
+ * Context: can sleep
+ *
+ * This call may only be used from a context that may sleep.  The sleep
+ * is non-interruptible, and has no timeout.  Low-overhead controller
+ * drivers may DMA directly into and out of the message buffers.
+ *
+ * This call should be used by drivers that require exclusive access to the
+ * SPI bus. It has to be preceeded by a spi_bus_lock call. The SPI bus must
+ * be released by a spi_bus_unlock call when the exclusive access is over.
+ *
+ * It returns zero on success, else a negative error code.
+ */
+int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
+{
+	return __spi_sync(spi, message, 1);
+}
+EXPORT_SYMBOL_GPL(spi_sync_locked);
+
+/**
+ * spi_bus_lock - obtain a lock for exclusive SPI bus usage
+ * @master: SPI bus master that should be locked for exclusive bus access
+ * Context: can sleep
+ *
+ * This call may only be used from a context that may sleep.  The sleep
+ * is non-interruptible, and has no timeout.
+ *
+ * This call should be used by drivers that require exclusive access to the
+ * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
+ * exclusive access is over. Data transfer must be done by spi_sync_locked
+ * and spi_async_locked calls when the SPI bus lock is held.
+ *
+ * It returns zero on success, else a negative error code.
+ */
+int spi_bus_lock(struct spi_master *master)
+{
+	unsigned long flags;
+
+	mutex_lock(&master->bus_lock_mutex);
+
+	spin_lock_irqsave(&master->bus_lock_spinlock, flags);
+	master->bus_lock_flag = 1;
+	spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
+
+	/* mutex remains locked until spi_bus_unlock is called */
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(spi_bus_lock);
+
+/**
+ * spi_bus_unlock - release the lock for exclusive SPI bus usage
+ * @master: SPI bus master that was locked for exclusive bus access
+ * Context: can sleep
+ *
+ * This call may only be used from a context that may sleep.  The sleep
+ * is non-interruptible, and has no timeout.
+ *
+ * This call releases an SPI bus lock previously obtained by an spi_bus_lock
+ * call.
+ *
+ * It returns zero on success, else a negative error code.
+ */
+int spi_bus_unlock(struct spi_master *master)
+{
+	master->bus_lock_flag = 0;
+
+	mutex_unlock(&master->bus_lock_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(spi_bus_unlock);
+
 /* portable code must never pass more than 32 bytes */
 #define	SPI_BUFSIZ	max(32,SMP_CACHE_BYTES)
 

drivers/spi/spi_bitbang.c

@@ -259,7 +259,6 @@ static void bitbang_work(struct work_struct *work)
 	struct spi_bitbang	*bitbang =
 		container_of(work, struct spi_bitbang, work);
 	unsigned long		flags;
-	int			do_setup = -1;
 	int			(*setup_transfer)(struct spi_device *,
 					struct spi_transfer *);
 
@@ -275,6 +274,7 @@ static void bitbang_work(struct work_struct *work)
 		unsigned		tmp;
 		unsigned		cs_change;
 		int			status;
+		int			do_setup = -1;
 
 		m = container_of(bitbang->queue.next, struct spi_message,
 				queue);
@@ -307,6 +307,8 @@ static void bitbang_work(struct work_struct *work)
 				status = setup_transfer(spi, t);
 				if (status < 0)
 					break;
+				if (do_setup == -1)
+					do_setup = 0;
 			}
 
 			/* set up default clock polarity, and activate chip;
@@ -367,11 +369,6 @@ static void bitbang_work(struct work_struct *work)
 		m->status = status;
 		m->complete(m->context);
 
-		/* restore speed and wordsize if it was overridden */
-		if (do_setup == 1)
-			setup_transfer(spi, NULL);
-		do_setup = 0;
-
 		/* normally deactivate chipselect ... unless no error and
 		 * cs_change has hinted that the next message will probably
 		 * be for this chip too.

drivers/spi/spi_bitbang_txrx.h

@@ -44,7 +44,7 @@
 
 static inline u32
 bitbang_txrx_be_cpha0(struct spi_device *spi,
-		unsigned nsecs, unsigned cpol,
+		unsigned nsecs, unsigned cpol, unsigned flags,
 		u32 word, u8 bits)
 {
 	/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */
@@ -53,6 +53,7 @@ bitbang_txrx_be_cpha0(struct spi_device *spi,
 	for (word <<= (32 - bits); likely(bits); bits--) {
 
 		/* setup MSB (to slave) on trailing edge */
+		if ((flags & SPI_MASTER_NO_TX) == 0)
 			setmosi(spi, word & (1 << 31));
 		spidelay(nsecs);	/* T(setup) */
 
@@ -61,6 +62,7 @@ bitbang_txrx_be_cpha0(struct spi_device *spi,
 
 		/* sample MSB (from slave) on leading edge */
 		word <<= 1;
+		if ((flags & SPI_MASTER_NO_RX) == 0)
 			word |= getmiso(spi);
 		setsck(spi, cpol);
 	}
@@ -69,7 +71,7 @@ bitbang_txrx_be_cpha0(struct spi_device *spi,
 
 static inline u32
 bitbang_txrx_be_cpha1(struct spi_device *spi,
-		unsigned nsecs, unsigned cpol,
+		unsigned nsecs, unsigned cpol, unsigned flags,
 		u32 word, u8 bits)
 {
 	/* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */
@@ -79,6 +81,7 @@ bitbang_txrx_be_cpha1(struct spi_device *spi,
 
 		/* setup MSB (to slave) on leading edge */
 		setsck(spi, !cpol);
+		if ((flags & SPI_MASTER_NO_TX) == 0)
 			setmosi(spi, word & (1 << 31));
 		spidelay(nsecs); /* T(setup) */
 
@@ -87,6 +90,7 @@ bitbang_txrx_be_cpha1(struct spi_device *spi,
 
 		/* sample MSB (from slave) on trailing edge */
 		word <<= 1;
+		if ((flags & SPI_MASTER_NO_RX) == 0)
 			word |= getmiso(spi);
 	}
 	return word;

drivers/spi/spi_butterfly.c

@@ -156,7 +156,7 @@ butterfly_txrx_word_mode0(struct spi_device *spi,
 		unsigned nsecs,
 		u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
+	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
 }
 
 /*----------------------------------------------------------------------*/

drivers/spi/spi_gpio.c

@@ -146,25 +146,63 @@ static inline int getmiso(const struct spi_device *spi)
 static u32 spi_gpio_txrx_word_mode0(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
+	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
 }
 
 static u32 spi_gpio_txrx_word_mode1(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
+	return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);
 }
 
 static u32 spi_gpio_txrx_word_mode2(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
+	return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);
 }
 
 static u32 spi_gpio_txrx_word_mode3(struct spi_device *spi,
 		unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
+	return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
+}
+
+/*
+ * These functions do not call setmosi or getmiso if respective flag
+ * (SPI_MASTER_NO_RX or SPI_MASTER_NO_TX) is set, so they are safe to
+ * call when such pin is not present or defined in the controller.
+ * A separate set of callbacks is defined to get highest possible
+ * speed in the generic case (when both MISO and MOSI lines are
+ * available), as optimiser will remove the checks when argument is
+ * constant.
+ */
+
+static u32 spi_gpio_spec_txrx_word_mode0(struct spi_device *spi,
+		unsigned nsecs, u32 word, u8 bits)
+{
+	unsigned flags = spi->master->flags;
+	return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits);
+}
+
+static u32 spi_gpio_spec_txrx_word_mode1(struct spi_device *spi,
+		unsigned nsecs, u32 word, u8 bits)
+{
+	unsigned flags = spi->master->flags;
+	return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits);
+}
+
+static u32 spi_gpio_spec_txrx_word_mode2(struct spi_device *spi,
+		unsigned nsecs, u32 word, u8 bits)
+{
+	unsigned flags = spi->master->flags;
+	return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits);
+}
+
+static u32 spi_gpio_spec_txrx_word_mode3(struct spi_device *spi,
+		unsigned nsecs, u32 word, u8 bits)
+{
+	unsigned flags = spi->master->flags;
+	return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, word, bits);
 }
 
 /*----------------------------------------------------------------------*/
@@ -232,19 +270,30 @@ static int __init spi_gpio_alloc(unsigned pin, const char *label, bool is_in)
 }
 
 static int __init
-spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label)
+spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label,
+	u16 *res_flags)
 {
 	int value;
 
 	/* NOTE:  SPI_*_GPIO symbols may reference "pdata" */
 
+	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI) {
 		value = spi_gpio_alloc(SPI_MOSI_GPIO, label, false);
 		if (value)
 			goto done;
+	} else {
+		/* HW configuration without MOSI pin */
+		*res_flags |= SPI_MASTER_NO_TX;
+	}
 
+	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO) {
 		value = spi_gpio_alloc(SPI_MISO_GPIO, label, true);
 		if (value)
 			goto free_mosi;
+	} else {
+		/* HW configuration without MISO pin */
+		*res_flags |= SPI_MASTER_NO_RX;
+	}
 
 	value = spi_gpio_alloc(SPI_SCK_GPIO, label, false);
 	if (value)
@@ -253,8 +302,10 @@ spi_gpio_request(struct spi_gpio_platform_data *pdata, const char *label)
 	goto done;
 
 free_miso:
+	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
 		gpio_free(SPI_MISO_GPIO);
 free_mosi:
+	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
 		gpio_free(SPI_MOSI_GPIO);
 done:
 	return value;
@@ -266,6 +317,7 @@ static int __init spi_gpio_probe(struct platform_device *pdev)
 	struct spi_master		*master;
 	struct spi_gpio			*spi_gpio;
 	struct spi_gpio_platform_data	*pdata;
+	u16 master_flags = 0;
 
 	pdata = pdev->dev.platform_data;
 #ifdef GENERIC_BITBANG
@@ -273,7 +325,7 @@ static int __init spi_gpio_probe(struct platform_device *pdev)
 		return -ENODEV;
 #endif
 
-	status = spi_gpio_request(pdata, dev_name(&pdev->dev));
+	status = spi_gpio_request(pdata, dev_name(&pdev->dev), &master_flags);
 	if (status < 0)
 		return status;
 
@@ -289,6 +341,7 @@ static int __init spi_gpio_probe(struct platform_device *pdev)
 	if (pdata)
 		spi_gpio->pdata = *pdata;
 
+	master->flags = master_flags;
 	master->bus_num = pdev->id;
 	master->num_chipselect = SPI_N_CHIPSEL;
 	master->setup = spi_gpio_setup;
@@ -296,10 +349,18 @@ static int __init spi_gpio_probe(struct platform_device *pdev)
 
 	spi_gpio->bitbang.master = spi_master_get(master);
 	spi_gpio->bitbang.chipselect = spi_gpio_chipselect;
+
+	if ((master_flags & (SPI_MASTER_NO_RX | SPI_MASTER_NO_RX)) == 0) {
 		spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0;
 		spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1;
 		spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2;
 		spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_word_mode3;
+	} else {
+		spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_spec_txrx_word_mode0;
+		spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_spec_txrx_word_mode1;
+		spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_spec_txrx_word_mode2;
+		spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3;
+	}
 	spi_gpio->bitbang.setup_transfer = spi_bitbang_setup_transfer;
 	spi_gpio->bitbang.flags = SPI_CS_HIGH;
 
@@ -307,7 +368,9 @@ static int __init spi_gpio_probe(struct platform_device *pdev)
 	if (status < 0) {
 		spi_master_put(spi_gpio->bitbang.master);
 gpio_free:
+		if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
 			gpio_free(SPI_MISO_GPIO);
+		if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
 			gpio_free(SPI_MOSI_GPIO);
 		gpio_free(SPI_SCK_GPIO);
 		spi_master_put(master);
@@ -331,7 +394,9 @@ static int __exit spi_gpio_remove(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, NULL);
 
+	if (SPI_MISO_GPIO != SPI_GPIO_NO_MISO)
 		gpio_free(SPI_MISO_GPIO);
+	if (SPI_MOSI_GPIO != SPI_GPIO_NO_MOSI)
 		gpio_free(SPI_MOSI_GPIO);
 	gpio_free(SPI_SCK_GPIO);
 

drivers/spi/spi_lm70llp.c

@@ -191,7 +191,7 @@ static void lm70_chipselect(struct spi_device *spi, int value)
  */
 static u32 lm70_txrx(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
+	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
 }
 
 static void spi_lm70llp_attach(struct parport *p)

drivers/spi/spi_s3c24xx_gpio.c

@@ -64,25 +64,25 @@ static inline u32 getmiso(struct spi_device *dev)
 static u32 s3c2410_spigpio_txrx_mode0(struct spi_device *spi,
 				      unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
+	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
 }
 
 static u32 s3c2410_spigpio_txrx_mode1(struct spi_device *spi,
 				      unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
+	return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);
 }
 
 static u32 s3c2410_spigpio_txrx_mode2(struct spi_device *spi,
 				      unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
+	return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);
 }
 
 static u32 s3c2410_spigpio_txrx_mode3(struct spi_device *spi,
 				      unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
+	return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
 }
 
 

drivers/spi/spi_sh_sci.c

@@ -83,25 +83,25 @@ static inline u32 getmiso(struct spi_device *dev)
 static u32 sh_sci_spi_txrx_mode0(struct spi_device *spi,
 				      unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
+	return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
 }
 
 static u32 sh_sci_spi_txrx_mode1(struct spi_device *spi,
 				      unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
+	return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);
 }
 
 static u32 sh_sci_spi_txrx_mode2(struct spi_device *spi,
 				      unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
+	return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);
 }
 
 static u32 sh_sci_spi_txrx_mode3(struct spi_device *spi,
 				      unsigned nsecs, u32 word, u8 bits)
 {
-	return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
+	return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
 }
 
 static void sh_sci_spi_chipselect(struct spi_device *dev, int value)

include/linux/spi/spi.h

@@ -262,6 +262,13 @@ struct spi_master {
 #define SPI_MASTER_NO_RX	BIT(1)		/* can't do buffer read */
 #define SPI_MASTER_NO_TX	BIT(2)		/* can't do buffer write */
 
+	/* lock and mutex for SPI bus locking */
+	spinlock_t		bus_lock_spinlock;
+	struct mutex		bus_lock_mutex;
+
+	/* flag indicating that the SPI bus is locked for exclusive use */
+	bool			bus_lock_flag;
+
 	/* Setup mode and clock, etc (spi driver may call many times).
 	 *
 	 * IMPORTANT:  this may be called when transfers to another
@@ -542,6 +549,8 @@ static inline void spi_message_free(struct spi_message *m)
 
 extern int spi_setup(struct spi_device *spi);
 extern int spi_async(struct spi_device *spi, struct spi_message *message);
+extern int spi_async_locked(struct spi_device *spi,
+			    struct spi_message *message);
 
 /*---------------------------------------------------------------------------*/
 
@@ -551,6 +560,9 @@ extern int spi_async(struct spi_device *spi, struct spi_message *message);
  */
 
 extern int spi_sync(struct spi_device *spi, struct spi_message *message);
+extern int spi_sync_locked(struct spi_device *spi, struct spi_message *message);
+extern int spi_bus_lock(struct spi_master *master);
+extern int spi_bus_unlock(struct spi_master *master);
 
 /**
  * spi_write - SPI synchronous write

include/linux/spi/spi_gpio.h

@@ -29,11 +29,16 @@
  * SPI_GPIO_NO_CHIPSELECT to the controller_data:
  *		.controller_data = (void *) SPI_GPIO_NO_CHIPSELECT;
  *
+ * If the MISO or MOSI pin is not available then it should be set to
+ * SPI_GPIO_NO_MISO or SPI_GPIO_NO_MOSI.
+ *
  * If the bitbanged bus is later switched to a "native" controller,
  * that platform_device and controller_data should be removed.
  */
 
 #define SPI_GPIO_NO_CHIPSELECT		((unsigned long)-1l)
+#define SPI_GPIO_NO_MISO		((unsigned long)-1l)
+#define SPI_GPIO_NO_MOSI		((unsigned long)-1l)
 
 /**
  * struct spi_gpio_platform_data - parameter for bitbanged SPI master