diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi.c | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 8a30c6b66a64..85c18d8a86b3 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -526,6 +526,95 @@ int spi_register_board_info(struct spi_board_info const *info, unsigned n) /*-------------------------------------------------------------------------*/ +static void spi_set_cs(struct spi_device *spi, bool enable) +{ + if (spi->mode & SPI_CS_HIGH) + enable = !enable; + + if (spi->cs_gpio >= 0) + gpio_set_value(spi->cs_gpio, !enable); + else if (spi->master->set_cs) + spi->master->set_cs(spi, !enable); +} + +/* + * spi_transfer_one_message - Default implementation of transfer_one_message() + * + * This is a standard implementation of transfer_one_message() for + * drivers which impelment a transfer_one() operation. It provides + * standard handling of delays and chip select management. + */ +static int spi_transfer_one_message(struct spi_master *master, + struct spi_message *msg) +{ + struct spi_transfer *xfer; + bool cur_cs = true; + bool keep_cs = false; + int ret = 0; + + spi_set_cs(msg->spi, true); + + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + trace_spi_transfer_start(msg, xfer); + + INIT_COMPLETION(master->xfer_completion); + + ret = master->transfer_one(master, msg->spi, xfer); + if (ret < 0) { + dev_err(&msg->spi->dev, + "SPI transfer failed: %d\n", ret); + goto out; + } + + if (ret > 0) + wait_for_completion(&master->xfer_completion); + + trace_spi_transfer_stop(msg, xfer); + + if (msg->status != -EINPROGRESS) + goto out; + + if (xfer->delay_usecs) + udelay(xfer->delay_usecs); + + if (xfer->cs_change) { + if (list_is_last(&xfer->transfer_list, + &msg->transfers)) { + keep_cs = true; + } else { + cur_cs = !cur_cs; + spi_set_cs(msg->spi, cur_cs); + } + } + + msg->actual_length += xfer->len; + } + +out: + if (ret != 0 || !keep_cs) + spi_set_cs(msg->spi, false); + + if (msg->status == -EINPROGRESS) + msg->status = ret; + + spi_finalize_current_message(master); + + return ret; +} + +/** + * spi_finalize_current_transfer - report completion of a transfer + * + * Called by SPI drivers using the core transfer_one_message() + * implementation to notify it that the current interrupt driven + * transfer has finised and the next one may be scheduled. + */ +void spi_finalize_current_transfer(struct spi_master *master) +{ + complete(&master->xfer_completion); +} +EXPORT_SYMBOL_GPL(spi_finalize_current_transfer); + /** * spi_pump_messages - kthread work function which processes spi message queue * @work: pointer to kthread work struct contained in the master struct @@ -836,6 +925,8 @@ static int spi_master_initialize_queue(struct spi_master *master) master->queued = true; master->transfer = spi_queued_transfer; + if (!master->transfer_one_message) + master->transfer_one_message = spi_transfer_one_message; /* Initialize and start queue */ ret = spi_init_queue(master); @@ -1242,6 +1333,7 @@ int spi_register_master(struct spi_master *master) spin_lock_init(&master->bus_lock_spinlock); mutex_init(&master->bus_lock_mutex); master->bus_lock_flag = 0; + init_completion(&master->xfer_completion); /* register the device, then userspace will see it. * registration fails if the bus ID is in use. |
