diff options
Diffstat (limited to 'drivers/spi/spi.c')
| -rw-r--r-- | drivers/spi/spi.c | 45 |
1 files changed, 23 insertions, 22 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index b31f4431849..682a6a48fec 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -485,6 +485,15 @@ void spi_unregister_master(struct spi_master *master) } 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 @@ -499,17 +508,12 @@ struct spi_master *spi_busnum_to_master(u16 bus_num) { struct device *dev; struct spi_master *master = NULL; - struct spi_master *m; - - down(&spi_master_class.sem); - list_for_each_entry(dev, &spi_master_class.children, node) { - m = container_of(dev, struct spi_master, dev); - if (m->bus_num == bus_num) { - master = spi_master_get(m); - break; - } - } - up(&spi_master_class.sem); + + dev = class_find_device(&spi_master_class, &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); @@ -541,10 +545,7 @@ static void spi_complete(void *arg) * 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) { @@ -554,8 +555,10 @@ 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; } @@ -589,7 +592,7 @@ 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; @@ -615,7 +618,7 @@ int spi_write_then_read(struct spi_device *spi, } /* ... 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; @@ -628,13 +631,11 @@ int spi_write_then_read(struct spi_device *spi, /* 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); |