* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
-#include <linux/autoconf.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/cache.h>
+#include <linux/mutex.h>
+#include <linux/mod_devicetable.h>
#include <linux/spi/spi.h>
*/
static void spidev_release(struct device *dev)
{
- const struct spi_device *spi = to_spi_device(dev);
+ struct spi_device *spi = to_spi_device(dev);
/* spi masters may cleanup for released devices */
if (spi->master->cleanup)
{
const struct spi_device *spi = to_spi_device(dev);
- return snprintf(buf, BUS_ID_SIZE + 1, "%s\n", spi->modalias);
+ return sprintf(buf, "%s\n", spi->modalias);
}
static struct device_attribute spi_dev_attrs[] = {
* and the sysfs version makes coldplug work too.
*/
+static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
+ const struct spi_device *sdev)
+{
+ while (id->name[0]) {
+ if (!strcmp(sdev->modalias, id->name))
+ return id;
+ id++;
+ }
+ return NULL;
+}
+
+const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
+{
+ const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
+
+ return spi_match_id(sdrv->id_table, sdev);
+}
+EXPORT_SYMBOL_GPL(spi_get_device_id);
+
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);
+
+ if (sdrv->id_table)
+ return !!spi_match_id(sdrv->id_table, spi);
- return strncmp(spi->modalias, drv->name, BUS_ID_SIZE) == 0;
+ return strcmp(spi->modalias, drv->name) == 0;
}
-static int spi_uevent(struct device *dev, char **envp, int num_envp,
- char *buffer, int buffer_size)
+static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
{
const struct spi_device *spi = to_spi_device(dev);
- envp[0] = buffer;
- snprintf(buffer, buffer_size, "MODALIAS=%s", spi->modalias);
- envp[1] = NULL;
+ add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
return 0;
}
#ifdef CONFIG_PM
-/*
- * NOTE: the suspend() method for an spi_master controller driver
- * should verify that all its child devices are marked as suspended;
- * suspend requests delivered through sysfs power/state files don't
- * enforce such constraints.
- */
static int spi_suspend(struct device *dev, pm_message_t message)
{
- int value;
+ int value = 0;
struct spi_driver *drv = to_spi_driver(dev->driver);
- if (!drv || !drv->suspend)
- return 0;
-
/* suspend will stop irqs and dma; no more i/o */
- value = drv->suspend(to_spi_device(dev), message);
- if (value == 0)
- dev->power.power_state = message;
+ if (drv) {
+ if (drv->suspend)
+ value = drv->suspend(to_spi_device(dev), message);
+ else
+ dev_dbg(dev, "... can't suspend\n");
+ }
return value;
}
static int spi_resume(struct device *dev)
{
- int value;
+ int value = 0;
struct spi_driver *drv = to_spi_driver(dev->driver);
- if (!drv || !drv->resume)
- return 0;
-
/* resume may restart the i/o queue */
- value = drv->resume(to_spi_device(dev));
- if (value == 0)
- dev->power.power_state = PMSG_ON;
+ if (drv) {
+ if (drv->resume)
+ value = drv->resume(to_spi_device(dev));
+ else
+ dev_dbg(dev, "... can't resume\n");
+ }
return value;
}
sdrv->shutdown(to_spi_device(dev));
}
+/**
+ * spi_register_driver - register a SPI driver
+ * @sdrv: the driver to register
+ * Context: can sleep
+ */
int spi_register_driver(struct spi_driver *sdrv)
{
sdrv->driver.bus = &spi_bus_type;
};
static LIST_HEAD(board_list);
-static DECLARE_MUTEX(board_lock);
+static DEFINE_MUTEX(board_lock);
+
+/**
+ * spi_alloc_device - Allocate a new SPI device
+ * @master: Controller to which device is connected
+ * Context: can sleep
+ *
+ * Allows a driver to allocate and initialize a spi_device without
+ * registering it immediately. This allows a driver to directly
+ * fill the spi_device with device parameters before calling
+ * spi_add_device() on it.
+ *
+ * Caller is responsible to call spi_add_device() on the returned
+ * spi_device structure to add it to the SPI master. If the caller
+ * needs to discard the spi_device without adding it, then it should
+ * call spi_dev_put() on it.
+ *
+ * Returns a pointer to the new device, or NULL.
+ */
+struct spi_device *spi_alloc_device(struct spi_master *master)
+{
+ struct spi_device *spi;
+ struct device *dev = master->dev.parent;
+
+ if (!spi_master_get(master))
+ return NULL;
+
+ spi = kzalloc(sizeof *spi, GFP_KERNEL);
+ if (!spi) {
+ dev_err(dev, "cannot alloc spi_device\n");
+ spi_master_put(master);
+ return NULL;
+ }
+
+ spi->master = master;
+ spi->dev.parent = dev;
+ spi->dev.bus = &spi_bus_type;
+ spi->dev.release = spidev_release;
+ device_initialize(&spi->dev);
+ return spi;
+}
+EXPORT_SYMBOL_GPL(spi_alloc_device);
+/**
+ * spi_add_device - Add spi_device allocated with spi_alloc_device
+ * @spi: spi_device to register
+ *
+ * Companion function to spi_alloc_device. Devices allocated with
+ * spi_alloc_device can be added onto the spi bus with this function.
+ *
+ * Returns 0 on success; negative errno on failure
+ */
+int spi_add_device(struct spi_device *spi)
+{
+ static DEFINE_MUTEX(spi_add_lock);
+ struct device *dev = spi->master->dev.parent;
+ int status;
+
+ /* Chipselects are numbered 0..max; validate. */
+ if (spi->chip_select >= spi->master->num_chipselect) {
+ dev_err(dev, "cs%d >= max %d\n",
+ spi->chip_select,
+ spi->master->num_chipselect);
+ return -EINVAL;
+ }
+
+ /* Set the bus ID string */
+ dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
+ spi->chip_select);
+
+
+ /* We need to make sure there's no other device with this
+ * chipselect **BEFORE** we call setup(), else we'll trash
+ * its configuration. Lock against concurrent add() calls.
+ */
+ mutex_lock(&spi_add_lock);
+
+ if (bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev))
+ != NULL) {
+ dev_err(dev, "chipselect %d already in use\n",
+ spi->chip_select);
+ status = -EBUSY;
+ goto done;
+ }
+
+ /* Drivers may modify this initial i/o setup, but will
+ * normally rely on the device being setup. Devices
+ * using SPI_CS_HIGH can't coexist well otherwise...
+ */
+ status = spi_setup(spi);
+ if (status < 0) {
+ dev_err(dev, "can't %s %s, status %d\n",
+ "setup", dev_name(&spi->dev), status);
+ goto done;
+ }
-/* On typical mainboards, this is purely internal; and it's not needed
+ /* 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);
+ else
+ dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
+
+done:
+ mutex_unlock(&spi_add_lock);
+ return status;
+}
+EXPORT_SYMBOL_GPL(spi_add_device);
+
+/**
+ * spi_new_device - instantiate one new SPI device
+ * @master: Controller to which device is connected
+ * @chip: Describes the SPI device
+ * Context: can sleep
+ *
+ * On typical mainboards, this is purely internal; and it's not needed
* after board init creates the hard-wired devices. Some development
* platforms may not be able to use spi_register_board_info though, and
* this is exported so that for example a USB or parport based adapter
* driver could add devices (which it would learn about out-of-band).
+ *
+ * Returns the new device, or NULL.
*/
-struct spi_device *__init_or_module
-spi_new_device(struct spi_master *master, struct spi_board_info *chip)
+struct spi_device *spi_new_device(struct spi_master *master,
+ struct spi_board_info *chip)
{
struct spi_device *proxy;
- struct device *dev = master->cdev.dev;
int status;
- /* NOTE: caller did any chip->bus_num checks necessary */
+ /* NOTE: caller did any chip->bus_num checks necessary.
+ *
+ * Also, unless we change the return value convention to use
+ * error-or-pointer (not NULL-or-pointer), troubleshootability
+ * suggests syslogged diagnostics are best here (ugh).
+ */
- if (!spi_master_get(master))
+ proxy = spi_alloc_device(master);
+ if (!proxy)
return NULL;
- proxy = kzalloc(sizeof *proxy, GFP_KERNEL);
- if (!proxy) {
- dev_err(dev, "can't alloc dev for cs%d\n",
- chip->chip_select);
- goto fail;
- }
- proxy->master = master;
+ WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
+
proxy->chip_select = chip->chip_select;
proxy->max_speed_hz = chip->max_speed_hz;
proxy->mode = chip->mode;
proxy->irq = chip->irq;
- proxy->modalias = chip->modalias;
-
- snprintf(proxy->dev.bus_id, sizeof proxy->dev.bus_id,
- "%s.%u", master->cdev.class_id,
- chip->chip_select);
- proxy->dev.parent = dev;
- proxy->dev.bus = &spi_bus_type;
+ strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
proxy->dev.platform_data = (void *) chip->platform_data;
proxy->controller_data = chip->controller_data;
proxy->controller_state = NULL;
- proxy->dev.release = spidev_release;
- /* drivers may modify this default i/o setup */
- status = master->setup(proxy);
+ status = spi_add_device(proxy);
if (status < 0) {
- dev_dbg(dev, "can't %s %s, status %d\n",
- "setup", proxy->dev.bus_id, status);
- goto fail;
+ spi_dev_put(proxy);
+ return NULL;
}
- /* driver core catches callers that misbehave by defining
- * devices that already exist.
- */
- status = device_register(&proxy->dev);
- if (status < 0) {
- dev_dbg(dev, "can't %s %s, status %d\n",
- "add", proxy->dev.bus_id, status);
- goto fail;
- }
- dev_dbg(dev, "registered child %s\n", proxy->dev.bus_id);
return proxy;
-
-fail:
- spi_master_put(master);
- kfree(proxy);
- return NULL;
}
EXPORT_SYMBOL_GPL(spi_new_device);
-/*
+/**
+ * spi_register_board_info - register SPI devices for a given board
+ * @info: array of chip descriptors
+ * @n: how many descriptors are provided
+ * Context: can sleep
+ *
* Board-specific early init code calls this (probably during arch_initcall)
* with segments of the SPI device table. Any device nodes are created later,
* after the relevant parent SPI controller (bus_num) is defined. We keep
bi->n_board_info = n;
memcpy(bi->board_info, info, n * sizeof *info);
- down(&board_lock);
+ mutex_lock(&board_lock);
list_add_tail(&bi->list, &board_list);
- up(&board_lock);
+ mutex_unlock(&board_lock);
return 0;
}
* creates board info from kernel command lines
*/
-static void __init_or_module
-scan_boardinfo(struct spi_master *master)
+static void scan_boardinfo(struct spi_master *master)
{
struct boardinfo *bi;
- struct device *dev = master->cdev.dev;
- down(&board_lock);
+ 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;
- /* some controllers only have one chip, so they
- * might not use chipselects. otherwise, the
- * chipselects are numbered 0..max.
+ /* NOTE: this relies on spi_new_device to
+ * issue diagnostics when given bogus inputs
*/
- if (chip->chip_select >= master->num_chipselect
- && master->num_chipselect) {
- dev_dbg(dev, "cs%d > max %d\n",
- chip->chip_select,
- master->num_chipselect);
- continue;
- }
(void) spi_new_device(master, chip);
}
}
- up(&board_lock);
+ mutex_unlock(&board_lock);
}
/*-------------------------------------------------------------------------*/
-static void spi_master_release(struct class_device *cdev)
+static void spi_master_release(struct device *dev)
{
struct spi_master *master;
- master = container_of(cdev, struct spi_master, cdev);
+ master = container_of(dev, struct spi_master, dev);
kfree(master);
}
static struct class spi_master_class = {
.name = "spi_master",
.owner = THIS_MODULE,
- .release = spi_master_release,
+ .dev_release = spi_master_release,
};
/**
* spi_alloc_master - allocate SPI master controller
* @dev: the controller, possibly using the platform_bus
- * @size: how much driver-private data to preallocate; the pointer to this
- * memory is in the class_data field of the returned class_device,
+ * @size: how much zeroed driver-private data to allocate; the pointer to this
+ * memory is in the driver_data field of the returned device,
* accessible with spi_master_get_devdata().
+ * Context: can sleep
*
* This call is used only by SPI master controller drivers, which are the
* only ones directly touching chip registers. It's how they allocate
* the master's methods before calling spi_register_master(); and (after errors
* adding the device) calling spi_master_put() to prevent a memory leak.
*/
-struct spi_master * __init_or_module
-spi_alloc_master(struct device *dev, unsigned size)
+struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
{
struct spi_master *master;
if (!master)
return NULL;
- class_device_initialize(&master->cdev);
- master->cdev.class = &spi_master_class;
- master->cdev.dev = get_device(dev);
+ device_initialize(&master->dev);
+ master->dev.class = &spi_master_class;
+ master->dev.parent = get_device(dev);
spi_master_set_devdata(master, &master[1]);
return master;
/**
* spi_register_master - register SPI master controller
* @master: initialized master, originally from spi_alloc_master()
+ * Context: can sleep
*
* SPI master controllers connect to their drivers using some non-SPI bus,
* such as the platform bus. The final stage of probe() in that code
* After a successful return, the caller is responsible for calling
* spi_unregister_master().
*/
-int __init_or_module
-spi_register_master(struct spi_master *master)
+int spi_register_master(struct spi_master *master)
{
- static atomic_t dyn_bus_id = ATOMIC_INIT((1<<16) - 1);
- struct device *dev = master->cdev.dev;
+ static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
+ struct device *dev = master->dev.parent;
int status = -ENODEV;
int dynamic = 0;
if (!dev)
return -ENODEV;
+ /* even if it's just one always-selected device, there must
+ * be at least one chipselect
+ */
+ if (master->num_chipselect == 0)
+ return -EINVAL;
+
/* convention: dynamically assigned bus IDs count down from the max */
if (master->bus_num < 0) {
+ /* FIXME switch to an IDR based scheme, something like
+ * I2C now uses, so we can't run out of "dynamic" IDs
+ */
master->bus_num = atomic_dec_return(&dyn_bus_id);
dynamic = 1;
}
/* register the device, then userspace will see it.
* registration fails if the bus ID is in use.
*/
- snprintf(master->cdev.class_id, sizeof master->cdev.class_id,
- "spi%u", master->bus_num);
- status = class_device_add(&master->cdev);
+ dev_set_name(&master->dev, "spi%u", master->bus_num);
+ status = device_add(&master->dev);
if (status < 0)
goto done;
- dev_dbg(dev, "registered master %s%s\n", master->cdev.class_id,
+ dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
dynamic ? " (dynamic)" : "");
/* populate children from any spi device tables */
EXPORT_SYMBOL_GPL(spi_register_master);
-static int __unregister(struct device *dev, void *unused)
+static int __unregister(struct device *dev, void *master_dev)
{
/* note: before about 2.6.14-rc1 this would corrupt memory: */
- spi_unregister_device(to_spi_device(dev));
+ if (dev != master_dev)
+ spi_unregister_device(to_spi_device(dev));
return 0;
}
/**
* spi_unregister_master - unregister SPI master controller
* @master: the master being unregistered
+ * Context: can sleep
*
* This call is used only by SPI master controller drivers, which are the
* only ones directly touching chip registers.
*/
void spi_unregister_master(struct spi_master *master)
{
- (void) device_for_each_child(master->cdev.dev, NULL, __unregister);
- class_device_unregister(&master->cdev);
+ int dummy;
+
+ dummy = device_for_each_child(master->dev.parent, &master->dev,
+ __unregister);
+ device_unregister(&master->dev);
}
EXPORT_SYMBOL_GPL(spi_unregister_master);
+static int __spi_master_match(struct device *dev, void *data)
+{
+ struct spi_master *m;
+ u16 *bus_num = data;
+
+ m = container_of(dev, struct spi_master, dev);
+ return m->bus_num == *bus_num;
+}
+
/**
* spi_busnum_to_master - look up master associated with bus_num
* @bus_num: the master's bus number
+ * Context: can sleep
*
* This call may be used with devices that are registered after
* arch init time. It returns a refcounted pointer to the relevant
*/
struct spi_master *spi_busnum_to_master(u16 bus_num)
{
- if (bus_num) {
- char name[8];
- struct kobject *bus;
-
- snprintf(name, sizeof name, "spi%u", bus_num);
- bus = kset_find_obj(&spi_master_class.subsys.kset, name);
- if (bus)
- return container_of(bus, struct spi_master, cdev.kobj);
- }
- return NULL;
+ struct device *dev;
+ struct spi_master *master = NULL;
+
+ dev = class_find_device(&spi_master_class, NULL, &bus_num,
+ __spi_master_match);
+ if (dev)
+ master = container_of(dev, struct spi_master, dev);
+ /* reference got in class_find_device */
+ return master;
}
EXPORT_SYMBOL_GPL(spi_busnum_to_master);
/*-------------------------------------------------------------------------*/
+/* Core methods for SPI master protocol drivers. Some of the
+ * other core methods are currently defined as inline functions.
+ */
+
+/**
+ * spi_setup - setup SPI mode and clock rate
+ * @spi: the device whose settings are being modified
+ * Context: can sleep, and no requests are queued to the device
+ *
+ * SPI protocol drivers may need to update the transfer mode if the
+ * device doesn't work with its default. They may likewise need
+ * to update clock rates or word sizes from initial values. This function
+ * changes those settings, and must be called from a context that can sleep.
+ * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
+ * effect the next time the device is selected and data is transferred to
+ * or from it. When this function returns, the spi device is deselected.
+ *
+ * Note that this call will fail if the protocol driver specifies an option
+ * that the underlying controller or its driver does not support. For
+ * example, not all hardware supports wire transfers using nine bit words,
+ * LSB-first wire encoding, or active-high chipselects.
+ */
+int spi_setup(struct spi_device *spi)
+{
+ unsigned bad_bits;
+ int status;
+
+ /* help drivers fail *cleanly* when they need options
+ * that aren't supported with their current master
+ */
+ bad_bits = spi->mode & ~spi->master->mode_bits;
+ if (bad_bits) {
+ dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
+ bad_bits);
+ return -EINVAL;
+ }
+
+ if (!spi->bits_per_word)
+ spi->bits_per_word = 8;
+
+ status = spi->master->setup(spi);
+
+ dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
+ "%u bits/w, %u Hz max --> %d\n",
+ (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
+ (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
+ (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
+ (spi->mode & SPI_3WIRE) ? "3wire, " : "",
+ (spi->mode & SPI_LOOP) ? "loopback, " : "",
+ spi->bits_per_word, spi->max_speed_hz,
+ status);
+
+ return status;
+}
+EXPORT_SYMBOL_GPL(spi_setup);
+
+/**
+ * spi_async - asynchronous SPI transfer
+ * @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(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);
+}
+EXPORT_SYMBOL_GPL(spi_async);
+
+
+/*-------------------------------------------------------------------------*/
+
+/* Utility methods for SPI master protocol drivers, layered on
+ * top of the core. Some other utility methods are defined as
+ * inline functions.
+ */
+
static void spi_complete(void *arg)
{
complete(arg);
* spi_sync - blocking/synchronous SPI data transfers
* @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
* Also, the caller is guaranteeing that the memory associated with the
* message will not be freed before this call returns.
*
- * The return value is a negative error code if the message could not be
- * submitted, else zero. When the value is zero, then message->status is
- * also defined: it's the completion code for the transfer, either zero
- * or a negative error code from the controller driver.
+ * It returns zero on success, else a negative error code.
*/
int spi_sync(struct spi_device *spi, struct spi_message *message)
{
message->complete = spi_complete;
message->context = &done;
status = spi_async(spi, message);
- if (status == 0)
+ if (status == 0) {
wait_for_completion(&done);
+ status = message->status;
+ }
message->context = NULL;
return status;
}
* @spi: device with which data will be exchanged
* @txbuf: data to be written (need not be dma-safe)
* @n_tx: size of txbuf, in bytes
- * @rxbuf: buffer into which data will be read
- * @n_rx: size of rxbuf, in bytes (need not be dma-safe)
+ * @rxbuf: buffer into which data will be read (need not be dma-safe)
+ * @n_rx: size of rxbuf, in bytes
+ * Context: can sleep
*
* This performs a half duplex MicroWire style transaction with the
* device, sending txbuf and then reading rxbuf. The return value
* This call may only be used from a context that may sleep.
*
* Parameters to this routine are always copied using a small buffer;
- * performance-sensitive or bulk transfer code should instead use
+ * portable code should never use this for more than 32 bytes.
+ * Performance-sensitive or bulk transfer code should instead use
* spi_{async,sync}() calls with dma-safe buffers.
*/
int spi_write_then_read(struct spi_device *spi,
const u8 *txbuf, unsigned n_tx,
u8 *rxbuf, unsigned n_rx)
{
- static DECLARE_MUTEX(lock);
+ static DEFINE_MUTEX(lock);
int status;
struct spi_message message;
}
/* ... unless someone else is using the pre-allocated buffer */
- if (down_trylock(&lock)) {
+ if (!mutex_trylock(&lock)) {
local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
if (!local_buf)
return -ENOMEM;
/* do the i/o */
status = spi_sync(spi, &message);
- if (status == 0) {
+ if (status == 0)
memcpy(rxbuf, x[1].rx_buf, n_rx);
- status = message.status;
- }
if (x[0].tx_buf == buf)
- up(&lock);
+ mutex_unlock(&lock);
else
kfree(local_buf);
* driver registration) _could_ be dynamically linked (modular) ... costs
* include needing to have boardinfo data structures be much more public.
*/
-subsys_initcall(spi_init);
+postcore_initcall(spi_init);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff