#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
+#define SPI_BITBANG_CS_DELAY 100
+
/*----------------------------------------------------------------------*/
{
struct spi_bitbang_cs *cs = spi->controller_state;
struct spi_bitbang *bitbang;
- unsigned long flags;
bitbang = spi_master_get_devdata(spi->master);
*/
/* deselect chip (low or high) */
- spin_lock_irqsave(&bitbang->lock, flags);
+ mutex_lock(&bitbang->lock);
if (!bitbang->busy) {
bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
ndelay(cs->nsecs);
}
- spin_unlock_irqrestore(&bitbang->lock, flags);
+ mutex_unlock(&bitbang->lock);
return 0;
}
static int spi_bitbang_prepare_hardware(struct spi_master *spi)
{
struct spi_bitbang *bitbang;
- unsigned long flags;
bitbang = spi_master_get_devdata(spi);
- spin_lock_irqsave(&bitbang->lock, flags);
+ mutex_lock(&bitbang->lock);
bitbang->busy = 1;
- spin_unlock_irqrestore(&bitbang->lock, flags);
+ mutex_unlock(&bitbang->lock);
return 0;
}
static int spi_bitbang_transfer_one(struct spi_master *master,
- struct spi_message *m)
+ struct spi_device *spi,
+ struct spi_transfer *transfer)
{
- struct spi_bitbang *bitbang;
- unsigned nsecs;
- struct spi_transfer *t = NULL;
- unsigned cs_change;
- int status;
- int do_setup = -1;
- struct spi_device *spi = m->spi;
-
- bitbang = spi_master_get_devdata(master);
-
- /* FIXME this is made-up ... the correct value is known to
- * word-at-a-time bitbang code, and presumably chipselect()
- * should enforce these requirements too?
- */
- nsecs = 100;
-
- cs_change = 1;
- status = 0;
-
- list_for_each_entry(t, &m->transfers, transfer_list) {
-
- /* override speed or wordsize? */
- if (t->speed_hz || t->bits_per_word)
- do_setup = 1;
-
- /* init (-1) or override (1) transfer params */
- if (do_setup != 0) {
- if (bitbang->setup_transfer) {
- status = bitbang->setup_transfer(spi, t);
- if (status < 0)
- break;
- }
- if (do_setup == -1)
- do_setup = 0;
- }
-
- /* set up default clock polarity, and activate chip;
- * this implicitly updates clock and spi modes as
- * previously recorded for this device via setup().
- * (and also deselects any other chip that might be
- * selected ...)
- */
- if (cs_change) {
- bitbang->chipselect(spi, BITBANG_CS_ACTIVE);
- ndelay(nsecs);
- }
- cs_change = t->cs_change;
- if (!t->tx_buf && !t->rx_buf && t->len) {
- status = -EINVAL;
- break;
- }
-
- /* transfer data. the lower level code handles any
- * new dma mappings it needs. our caller always gave
- * us dma-safe buffers.
- */
- if (t->len) {
- /* REVISIT dma API still needs a designated
- * DMA_ADDR_INVALID; ~0 might be better.
- */
- if (!m->is_dma_mapped)
- t->rx_dma = t->tx_dma = 0;
- status = bitbang->txrx_bufs(spi, t);
- }
- if (status > 0)
- m->actual_length += status;
- if (status != t->len) {
- /* always report some kind of error */
- if (status >= 0)
- status = -EREMOTEIO;
- break;
- }
- status = 0;
+ struct spi_bitbang *bitbang = spi_master_get_devdata(master);
+ int status = 0;
- /* protocol tweaks before next transfer */
- if (t->delay_usecs)
- udelay(t->delay_usecs);
-
- if (cs_change &&
- !list_is_last(&t->transfer_list, &m->transfers)) {
- /* sometimes a short mid-message deselect of the chip
- * may be needed to terminate a mode or command
- */
- ndelay(nsecs);
- bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
- ndelay(nsecs);
- }
+ if (bitbang->setup_transfer) {
+ status = bitbang->setup_transfer(spi, transfer);
+ if (status < 0)
+ goto out;
}
- m->status = status;
+ if (transfer->len)
+ status = bitbang->txrx_bufs(spi, transfer);
- /* normally deactivate chipselect ... unless no error and
- * cs_change has hinted that the next message will probably
- * be for this chip too.
- */
- if (!(status == 0 && cs_change)) {
- ndelay(nsecs);
- bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
- ndelay(nsecs);
- }
+ if (status == transfer->len)
+ status = 0;
+ else if (status >= 0)
+ status = -EREMOTEIO;
- spi_finalize_current_message(master);
+out:
+ spi_finalize_current_transfer(master);
return status;
}
static int spi_bitbang_unprepare_hardware(struct spi_master *spi)
{
struct spi_bitbang *bitbang;
- unsigned long flags;
bitbang = spi_master_get_devdata(spi);
- spin_lock_irqsave(&bitbang->lock, flags);
+ mutex_lock(&bitbang->lock);
bitbang->busy = 0;
- spin_unlock_irqrestore(&bitbang->lock, flags);
+ mutex_unlock(&bitbang->lock);
return 0;
}
+static void spi_bitbang_set_cs(struct spi_device *spi, bool enable)
+{
+ struct spi_bitbang *bitbang = spi_master_get_devdata(spi->master);
+
+ /* SPI core provides CS high / low, but bitbang driver
+ * expects CS active
+ * spi device driver takes care of handling SPI_CS_HIGH
+ */
+ enable = (!!(spi->mode & SPI_CS_HIGH) == enable);
+
+ ndelay(SPI_BITBANG_CS_DELAY);
+ bitbang->chipselect(spi, enable ? BITBANG_CS_ACTIVE :
+ BITBANG_CS_INACTIVE);
+ ndelay(SPI_BITBANG_CS_DELAY);
+}
+
/*----------------------------------------------------------------------*/
/**
if (!master || !bitbang->chipselect)
return -EINVAL;
- spin_lock_init(&bitbang->lock);
+ mutex_init(&bitbang->lock);
if (!master->mode_bits)
master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags;
master->prepare_transfer_hardware = spi_bitbang_prepare_hardware;
master->unprepare_transfer_hardware = spi_bitbang_unprepare_hardware;
- master->transfer_one_message = spi_bitbang_transfer_one;
+ master->transfer_one = spi_bitbang_transfer_one;
+ master->set_cs = spi_bitbang_set_cs;
if (!bitbang->txrx_bufs) {
bitbang->use_dma = 0;
Code Review / kvmfornfv.git / blobdiff