spi/bitbang: Use core message pump

Convert drivers using bitbang to use the core mesasge pump infrastructure,
saving some code and meaning that these drivers get to take advantage of
work done on improving the core implementation.
Signed-off-by: Mark Brown <broonie@linaro.org>

drivers/spi/spi-bitbang.c

@@ -255,6 +255,21 @@ static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t)
  * Drivers can provide word-at-a-time i/o primitives, or provide
  * transfer-at-a-time ones to leverage dma or fifo hardware.
  */
+
+static int spi_bitbang_prepare_hardware(struct spi_master *spi)
+{
+	struct spi_bitbang 	*bitbang;
+	unsigned long		flags;
+
+	bitbang = spi_master_get_devdata(spi);
+
+	spin_lock_irqsave(&bitbang->lock, flags);
+	bitbang->busy = 1;
+	spin_unlock_irqrestore(&bitbang->lock, flags);
+
+	return 0;
+}
+
 static int spi_bitbang_transfer_one(struct spi_device *spi,
 				    struct spi_message *m)
 {
@@ -346,7 +361,6 @@ static int spi_bitbang_transfer_one(struct spi_device *spi,
 	}
 
 	m->status = status;
-	m->complete(m->context);
 
 	/* normally deactivate chipselect ... unless no error and
 	 * cs_change has hinted that the next message will probably
@@ -358,54 +372,23 @@ static int spi_bitbang_transfer_one(struct spi_device *spi,
 		ndelay(nsecs);
 	}
 
-	return status;
-}
+	spi_finalize_current_message(spi->master);
 
-static void bitbang_work(struct work_struct *work)
-{
-	struct spi_bitbang	*bitbang =
-		container_of(work, struct spi_bitbang, work);
-	unsigned long		flags;
-	struct spi_message	*m, *_m;
-
-	spin_lock_irqsave(&bitbang->lock, flags);
-	bitbang->busy = 1;
-	list_for_each_entry_safe(m, _m, &bitbang->queue, queue) {
-		list_del(&m->queue);
-		spin_unlock_irqrestore(&bitbang->lock, flags);
-
-		spi_bitbang_transfer_one(m->spi, m);
-
-		spin_lock_irqsave(&bitbang->lock, flags);
-	}
-	bitbang->busy = 0;
-	spin_unlock_irqrestore(&bitbang->lock, flags);
+	return status;
 }
 
-/**
- * spi_bitbang_transfer - default submit to transfer queue
- */
-static int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m)
+static int spi_bitbang_unprepare_hardware(struct spi_master *spi)
 {
 	struct spi_bitbang 	*bitbang;
 	unsigned long		flags;
-	int			status = 0;
 
-	m->actual_length = 0;
-	m->status = -EINPROGRESS;
-
-	bitbang = spi_master_get_devdata(spi->master);
+	bitbang = spi_master_get_devdata(spi);
 
 	spin_lock_irqsave(&bitbang->lock, flags);
-	if (!spi->max_speed_hz)
-		status = -ENETDOWN;
-	else {
-		list_add_tail(&m->queue, &bitbang->queue);
-		queue_work(bitbang->workqueue, &bitbang->work);
-	}
+	bitbang->busy = 0;
 	spin_unlock_irqrestore(&bitbang->lock, flags);
 
-	return status;
+	return 0;
 }
 
 /*----------------------------------------------------------------------*/
@@ -436,20 +419,22 @@ static int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m)
 int spi_bitbang_start(struct spi_bitbang *bitbang)
 {
 	struct spi_master *master = bitbang->master;
-	int status;
 
 	if (!master || !bitbang->chipselect)
 		return -EINVAL;
 
-	INIT_WORK(&bitbang->work, bitbang_work);
 	spin_lock_init(&bitbang->lock);
-	INIT_LIST_HEAD(&bitbang->queue);
 
 	if (!master->mode_bits)
 		master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags;
 
-	if (!master->transfer)
-		master->transfer = spi_bitbang_transfer;
+	if (master->transfer || master->transfer_one_message)
+		return -EINVAL;
+
+	master->prepare_transfer_hardware = spi_bitbang_prepare_hardware;
+	master->unprepare_transfer_hardware = spi_bitbang_unprepare_hardware;
+	master->transfer_one_message = spi_bitbang_transfer_one;
+
 	if (!bitbang->txrx_bufs) {
 		bitbang->use_dma = 0;
 		bitbang->txrx_bufs = spi_bitbang_bufs;
@@ -462,32 +447,11 @@ int spi_bitbang_start(struct spi_bitbang *bitbang)
 		}
 	} else if (!master->setup)
 		return -EINVAL;
-	if (master->transfer == spi_bitbang_transfer &&
-			!bitbang->setup_transfer)
-		return -EINVAL;
-
-	/* this task is the only thing to touch the SPI bits */
-	bitbang->busy = 0;
-	bitbang->workqueue = create_singlethread_workqueue(
-			dev_name(master->dev.parent));
-	if (bitbang->workqueue == NULL) {
-		status = -EBUSY;
-		goto err1;
-	}
 
 	/* driver may get busy before register() returns, especially
 	 * if someone registered boardinfo for devices
 	 */
-	status = spi_register_master(master);
-	if (status < 0)
-		goto err2;
-
-	return status;
-
-err2:
-	destroy_workqueue(bitbang->workqueue);
-err1:
-	return status;
+	return spi_register_master(master);
 }
 EXPORT_SYMBOL_GPL(spi_bitbang_start);
 
@@ -498,10 +462,6 @@ int spi_bitbang_stop(struct spi_bitbang *bitbang)
 {
 	spi_unregister_master(bitbang->master);
 
-	WARN_ON(!list_empty(&bitbang->queue));
-
-	destroy_workqueue(bitbang->workqueue);
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(spi_bitbang_stop);

include/linux/spi/spi_bitbang.h

@@ -4,11 +4,7 @@
 #include <linux/workqueue.h>
 
 struct spi_bitbang {
-	struct workqueue_struct	*workqueue;
-	struct work_struct	work;
-
 	spinlock_t		lock;
-	struct list_head	queue;
 	u8			busy;
 	u8			use_dma;
 	u8			flags;		/* extra spi->mode support */