diff options
Diffstat (limited to 'drivers/spi/spi.c')
| -rw-r--r-- | drivers/spi/spi.c | 335 |
1 files changed, 253 insertions, 82 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index b3a1f9259b62..709c836607de 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -23,15 +23,12 @@ #include <linux/init.h> #include <linux/cache.h> #include <linux/mutex.h> +#include <linux/of_device.h> #include <linux/slab.h> #include <linux/mod_devicetable.h> #include <linux/spi/spi.h> +#include <linux/of_spi.h> - -/* SPI bustype and spi_master class are registered after board init code - * provides the SPI device tables, ensuring that both are present by the - * time controller driver registration causes spi_devices to "enumerate". - */ static void spidev_release(struct device *dev) { struct spi_device *spi = to_spi_device(dev); @@ -85,6 +82,10 @@ static int spi_match_device(struct device *dev, struct device_driver *drv) const struct spi_device *spi = to_spi_device(dev); const struct spi_driver *sdrv = to_spi_driver(drv); + /* Attempt an OF style match */ + if (of_driver_match_device(dev, drv)) + return 1; + if (sdrv->id_table) return !!spi_match_id(sdrv->id_table, spi); @@ -196,11 +197,16 @@ EXPORT_SYMBOL_GPL(spi_register_driver); struct boardinfo { struct list_head list; - unsigned n_board_info; - struct spi_board_info board_info[0]; + struct spi_board_info board_info; }; static LIST_HEAD(board_list); +static LIST_HEAD(spi_master_list); + +/* + * Used to protect add/del opertion for board_info list and + * spi_master list, and their matching process + */ static DEFINE_MUTEX(board_lock); /** @@ -294,16 +300,16 @@ int spi_add_device(struct spi_device *spi) */ status = spi_setup(spi); if (status < 0) { - dev_err(dev, "can't %s %s, status %d\n", - "setup", dev_name(&spi->dev), status); + dev_err(dev, "can't setup %s, status %d\n", + dev_name(&spi->dev), status); goto done; } /* Device may be bound to an active driver when this returns */ status = device_add(&spi->dev); if (status < 0) - dev_err(dev, "can't %s %s, status %d\n", - "add", dev_name(&spi->dev), status); + dev_err(dev, "can't add %s, status %d\n", + dev_name(&spi->dev), status); else dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev)); @@ -365,6 +371,20 @@ struct spi_device *spi_new_device(struct spi_master *master, } EXPORT_SYMBOL_GPL(spi_new_device); +static void spi_match_master_to_boardinfo(struct spi_master *master, + struct spi_board_info *bi) +{ + struct spi_device *dev; + + if (master->bus_num != bi->bus_num) + return; + + dev = spi_new_device(master, bi); + if (!dev) + dev_err(master->dev.parent, "can't create new device for %s\n", + bi->modalias); +} + /** * spi_register_board_info - register SPI devices for a given board * @info: array of chip descriptors @@ -387,43 +407,25 @@ EXPORT_SYMBOL_GPL(spi_new_device); int __init spi_register_board_info(struct spi_board_info const *info, unsigned n) { - struct boardinfo *bi; + struct boardinfo *bi; + int i; - bi = kmalloc(sizeof(*bi) + n * sizeof *info, GFP_KERNEL); + bi = kzalloc(n * sizeof(*bi), GFP_KERNEL); if (!bi) return -ENOMEM; - bi->n_board_info = n; - memcpy(bi->board_info, info, n * sizeof *info); - mutex_lock(&board_lock); - list_add_tail(&bi->list, &board_list); - mutex_unlock(&board_lock); - return 0; -} - -/* FIXME someone should add support for a __setup("spi", ...) that - * creates board info from kernel command lines - */ + for (i = 0; i < n; i++, bi++, info++) { + struct spi_master *master; -static void scan_boardinfo(struct spi_master *master) -{ - struct boardinfo *bi; - - mutex_lock(&board_lock); - list_for_each_entry(bi, &board_list, list) { - struct spi_board_info *chip = bi->board_info; - unsigned n; - - for (n = bi->n_board_info; n > 0; n--, chip++) { - if (chip->bus_num != master->bus_num) - continue; - /* NOTE: this relies on spi_new_device to - * issue diagnostics when given bogus inputs - */ - (void) spi_new_device(master, chip); - } + memcpy(&bi->board_info, info, sizeof(*info)); + mutex_lock(&board_lock); + list_add_tail(&bi->list, &board_list); + list_for_each_entry(master, &spi_master_list, list) + spi_match_master_to_boardinfo(master, &bi->board_info); + mutex_unlock(&board_lock); } - mutex_unlock(&board_lock); + + return 0; } /*-------------------------------------------------------------------------*/ @@ -506,6 +508,7 @@ int spi_register_master(struct spi_master *master) { static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1); struct device *dev = master->dev.parent; + struct boardinfo *bi; int status = -ENODEV; int dynamic = 0; @@ -527,6 +530,10 @@ 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. */ @@ -537,20 +544,25 @@ int spi_register_master(struct spi_master *master) dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev), dynamic ? " (dynamic)" : ""); - /* populate children from any spi device tables */ - scan_boardinfo(master); + mutex_lock(&board_lock); + list_add_tail(&master->list, &spi_master_list); + list_for_each_entry(bi, &board_list, list) + spi_match_master_to_boardinfo(master, &bi->board_info); + mutex_unlock(&board_lock); + status = 0; + + /* Register devices from the device tree */ + of_register_spi_devices(master); done: return status; } EXPORT_SYMBOL_GPL(spi_register_master); -static int __unregister(struct device *dev, void *master_dev) +static int __unregister(struct device *dev, void *null) { - /* note: before about 2.6.14-rc1 this would corrupt memory: */ - if (dev != master_dev) - spi_unregister_device(to_spi_device(dev)); + spi_unregister_device(to_spi_device(dev)); return 0; } @@ -568,6 +580,10 @@ void spi_unregister_master(struct spi_master *master) { int dummy; + mutex_lock(&board_lock); + list_del(&master->list); + mutex_unlock(&board_lock); + dummy = device_for_each_child(master->dev.parent, &master->dev, __unregister); device_unregister(&master->dev); @@ -642,7 +658,7 @@ int spi_setup(struct spi_device *spi) */ bad_bits = spi->mode & ~spi->master->mode_bits; if (bad_bits) { - dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n", + dev_err(&spi->dev, "setup: unsupported mode bits %x\n", bad_bits); return -EINVAL; } @@ -666,6 +682,35 @@ 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 @@ -698,33 +743,68 @@ 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); + /*-------------------------------------------------------------------------*/ @@ -738,6 +818,32 @@ 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 @@ -761,21 +867,86 @@ 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) |