spi: spi-omap2-mcspi.c: Toggle CS after each word
This patch allows the board code to define SPI devices which needs to
toggle the chip select after every word send. This is needed to get a
better resolution reading e.g. an ADC data stream.
Apart from that, as in the normal code CS is controlled by software,
a transfer is done much faster.
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 31f6e84..12789fc 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -927,6 +927,7 @@
struct spi_device *spi;
struct spi_transfer *t = NULL;
+ struct spi_master *master;
int cs_active = 0;
struct omap2_mcspi_cs *cs;
struct omap2_mcspi_device_config *cd;
@@ -935,6 +936,7 @@
u32 chconf;
spi = m->spi;
+ master = spi->master;
cs = spi->controller_state;
cd = spi->controller_data;
@@ -952,6 +954,14 @@
if (!t->speed_hz && !t->bits_per_word)
par_override = 0;
}
+ if (cd && cd->cs_per_word) {
+ chconf = mcspi->ctx.modulctrl;
+ chconf &= ~OMAP2_MCSPI_MODULCTRL_SINGLE;
+ mcspi_write_reg(master, OMAP2_MCSPI_MODULCTRL, chconf);
+ mcspi->ctx.modulctrl =
+ mcspi_read_cs_reg(spi, OMAP2_MCSPI_MODULCTRL);
+ }
+
if (!cs_active) {
omap2_mcspi_force_cs(spi, 1);
@@ -1013,6 +1023,14 @@
if (cs_active)
omap2_mcspi_force_cs(spi, 0);
+ if (cd && cd->cs_per_word) {
+ chconf = mcspi->ctx.modulctrl;
+ chconf |= OMAP2_MCSPI_MODULCTRL_SINGLE;
+ mcspi_write_reg(master, OMAP2_MCSPI_MODULCTRL, chconf);
+ mcspi->ctx.modulctrl =
+ mcspi_read_cs_reg(spi, OMAP2_MCSPI_MODULCTRL);
+ }
+
omap2_mcspi_set_enable(spi, 0);
m->status = status;
