diff options
Diffstat (limited to 'drivers/spi/spi-bitbang.c')
| -rw-r--r-- | drivers/spi/spi-bitbang.c | 260 | 
1 files changed, 113 insertions, 147 deletions
| diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c index 1c2ba17760b8..8c11355dec23 100644 --- a/drivers/spi/spi-bitbang.c +++ b/drivers/spi/spi-bitbang.c @@ -255,150 +255,140 @@ 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 void bitbang_work(struct work_struct *work) + +static int spi_bitbang_prepare_hardware(struct spi_master *spi)  { -	struct spi_bitbang	*bitbang = -		container_of(work, struct spi_bitbang, work); +	struct spi_bitbang 	*bitbang;  	unsigned long		flags; -	struct spi_message	*m, *_m; + +	bitbang = spi_master_get_devdata(spi);  	spin_lock_irqsave(&bitbang->lock, flags);  	bitbang->busy = 1; -	list_for_each_entry_safe(m, _m, &bitbang->queue, queue) { -		struct spi_device	*spi; -		unsigned		nsecs; -		struct spi_transfer	*t = NULL; -		unsigned		tmp; -		unsigned		cs_change; -		int			status; -		int			do_setup = -1; - -		list_del(&m->queue); -		spin_unlock_irqrestore(&bitbang->lock, flags); - -		/* FIXME this is made-up ... the correct value is known to -		 * word-at-a-time bitbang code, and presumably chipselect() -		 * should enforce these requirements too? -		 */ -		nsecs = 100; +	spin_unlock_irqrestore(&bitbang->lock, flags); -		spi = m->spi; -		tmp = 0; -		cs_change = 1; -		status = 0; +	return 0; +} -		list_for_each_entry (t, &m->transfers, transfer_list) { - -			/* override speed or wordsize? */ -			if (t->speed_hz || t->bits_per_word) -				do_setup = 1; - -			/* init (-1) or override (1) transfer params */ -			if (do_setup != 0) { -				status = bitbang->setup_transfer(spi, t); -				if (status < 0) -					break; -				if (do_setup == -1) -					do_setup = 0; -			} - -			/* set up default clock polarity, and activate chip; -			 * this implicitly updates clock and spi modes as -			 * previously recorded for this device via setup(). -			 * (and also deselects any other chip that might be -			 * selected ...) -			 */ -			if (cs_change) { -				bitbang->chipselect(spi, BITBANG_CS_ACTIVE); -				ndelay(nsecs); -			} -			cs_change = t->cs_change; -			if (!t->tx_buf && !t->rx_buf && t->len) { -				status = -EINVAL; -				break; -			} +static int spi_bitbang_transfer_one(struct spi_master *master, +				    struct spi_message *m) +{ +	struct spi_bitbang 	*bitbang; +	unsigned		nsecs; +	struct spi_transfer	*t = NULL; +	unsigned		cs_change; +	int			status; +	int			do_setup = -1; +	struct spi_device	*spi = m->spi; + +	bitbang = spi_master_get_devdata(master); + +	/* FIXME this is made-up ... the correct value is known to +	 * word-at-a-time bitbang code, and presumably chipselect() +	 * should enforce these requirements too? +	 */ +	nsecs = 100; -			/* transfer data.  the lower level code handles any -			 * new dma mappings it needs. our caller always gave -			 * us dma-safe buffers. -			 */ -			if (t->len) { -				/* REVISIT dma API still needs a designated -				 * DMA_ADDR_INVALID; ~0 might be better. -				 */ -				if (!m->is_dma_mapped) -					t->rx_dma = t->tx_dma = 0; -				status = bitbang->txrx_bufs(spi, t); -			} -			if (status > 0) -				m->actual_length += status; -			if (status != t->len) { -				/* always report some kind of error */ -				if (status >= 0) -					status = -EREMOTEIO; +	cs_change = 1; +	status = 0; + +	list_for_each_entry (t, &m->transfers, transfer_list) { + +		/* override speed or wordsize? */ +		if (t->speed_hz || t->bits_per_word) +			do_setup = 1; + +		/* init (-1) or override (1) transfer params */ +		if (do_setup != 0) { +			status = bitbang->setup_transfer(spi, t); +			if (status < 0)  				break; -			} -			status = 0; - -			/* protocol tweaks before next transfer */ -			if (t->delay_usecs) -				udelay(t->delay_usecs); - -			if (cs_change && !list_is_last(&t->transfer_list, &m->transfers)) { -				/* sometimes a short mid-message deselect of the chip -				 * may be needed to terminate a mode or command -				 */ -				ndelay(nsecs); -				bitbang->chipselect(spi, BITBANG_CS_INACTIVE); -				ndelay(nsecs); -			} +			if (do_setup == -1) +				do_setup = 0;  		} -		m->status = status; -		m->complete(m->context); +		/* set up default clock polarity, and activate chip; +		 * this implicitly updates clock and spi modes as +		 * previously recorded for this device via setup(). +		 * (and also deselects any other chip that might be +		 * selected ...) +		 */ +		if (cs_change) { +			bitbang->chipselect(spi, BITBANG_CS_ACTIVE); +			ndelay(nsecs); +		} +		cs_change = t->cs_change; +		if (!t->tx_buf && !t->rx_buf && t->len) { +			status = -EINVAL; +			break; +		} -		/* normally deactivate chipselect ... unless no error and -		 * cs_change has hinted that the next message will probably -		 * be for this chip too. +		/* transfer data.  the lower level code handles any +		 * new dma mappings it needs. our caller always gave +		 * us dma-safe buffers.  		 */ -		if (!(status == 0 && cs_change)) { +		if (t->len) { +			/* REVISIT dma API still needs a designated +			 * DMA_ADDR_INVALID; ~0 might be better. +			 */ +			if (!m->is_dma_mapped) +				t->rx_dma = t->tx_dma = 0; +			status = bitbang->txrx_bufs(spi, t); +		} +		if (status > 0) +			m->actual_length += status; +		if (status != t->len) { +			/* always report some kind of error */ +			if (status >= 0) +				status = -EREMOTEIO; +			break; +		} +		status = 0; + +		/* protocol tweaks before next transfer */ +		if (t->delay_usecs) +			udelay(t->delay_usecs); + +		if (cs_change && !list_is_last(&t->transfer_list, &m->transfers)) { +			/* sometimes a short mid-message deselect of the chip +			 * may be needed to terminate a mode or command +			 */  			ndelay(nsecs);  			bitbang->chipselect(spi, BITBANG_CS_INACTIVE);  			ndelay(nsecs);  		} +	} + +	m->status = status; -		spin_lock_irqsave(&bitbang->lock, flags); +	/* normally deactivate chipselect ... unless no error and +	 * cs_change has hinted that the next message will probably +	 * be for this chip too. +	 */ +	if (!(status == 0 && cs_change)) { +		ndelay(nsecs); +		bitbang->chipselect(spi, BITBANG_CS_INACTIVE); +		ndelay(nsecs);  	} -	bitbang->busy = 0; -	spin_unlock_irqrestore(&bitbang->lock, flags); + +	spi_finalize_current_message(master); + +	return status;  } -/** - * spi_bitbang_transfer - default submit to transfer queue - */ -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; +	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;  } -EXPORT_SYMBOL_GPL(spi_bitbang_transfer);  /*----------------------------------------------------------------------*/ @@ -428,20 +418,22 @@ EXPORT_SYMBOL_GPL(spi_bitbang_transfer);  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; @@ -452,34 +444,12 @@ int spi_bitbang_start(struct spi_bitbang *bitbang)  			master->setup = spi_bitbang_setup;  			master->cleanup = spi_bitbang_cleanup;  		} -	} 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); @@ -490,10 +460,6 @@ 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); | 
