scottellis

static void spike_prepare_spi_message(void)
{
	spi_message_init(&spike_ctl.msg);

	/* put some changing values in tx_buff for testing */	
	spike_ctl.tx_buff[0] = spike_dev.test_data++;
	spike_ctl.tx_buff[1] = spike_dev.test_data++;
	spike_ctl.tx_buff[2] = spike_dev.test_data++;
	spike_ctl.tx_buff[3] = spike_dev.test_data++;

scottellis

static int spike_do_one_message(void)
{
	int status;

	if (down_interruptible(&spike_dev.spi_sem))
		return -ERESTARTSYS;

	if (!spike_dev.spi_device) {
		up(&spike_dev.spi_sem);
		return -ENODEV;

scottellis

static int __init add_spike_device_to_bus(void)
{
	struct spi_master *spi_master;
	struct spi_device *spi_device;
	struct device *pdev;
	char buff[64];
	int status = 0;

	spi_master = spi_busnum_to_master(SPI_BUS);
	if (!spi_master) {

scottellis

static void spike_completion_handler(void *arg)
{	
	spike_ctl.spi_callbacks++;
	spike_ctl.busy = 0;
}

scottellis

struct spike_control {
	struct spi_message msg;
	struct spi_transfer transfer;
	u32 busy;
	u32 spi_callbacks;
	u32 busy_counter;
	u8 *tx_buff; 
};

scottellis

struct spike_control {
	struct spi_message msg;
	struct spi_transfer transfer;
	u32 busy;
	u32 spi_callbacks;
	u32 busy_counter;
	u8 *tx_buff; 
};

scottellis

static int spike_queue_spi_write(void)
{
	int status;
	unsigned long flags;

	spi_message_init(&spike_ctl.msg);

	/* this gets called when the spi_message completes */
	spike_ctl.msg.complete = spike_completion_handler;
	spike_ctl.msg.context = NULL;

scottellis

struct spike_dev {
	spinlock_t spi_lock;
	struct semaphore fop_sem;
	dev_t devt;
	struct cdev cdev;
	struct class *class;
	struct spi_device *spi_device;
	struct hrtimer timer;
	u32 timer_period_sec;
	u32 timer_period_ns;

scottellis

static enum hrtimer_restart spike_timer_callback(struct hrtimer *timer)
{
	if (!spike_dev.running) {
		return HRTIMER_NORESTART;
	}

	/* busy means the previous message has not completed */
	if (spike_ctl.busy) {
		spike_ctl.busy_counter++;
	}

scottellis

struct spi_board_info {
	/* the device name and module name are coupled, like platform_bus;
	 * "modalias" is normally the driver name.
	 *
	 * platform_data goes to spi_device.dev.platform_data,
	 * controller_data goes to spi_device.controller_data,
	 * irq is copied too
	 */
	char		modalias[SPI_NAME_SIZE];
	const void	*platform_data;