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@xxxxxxxxx>
---
drivers/spi/spi-omap2-mcspi.c | 18 ++++++++++++++++++
include/linux/platform_data/spi-omap2-mcspi.h | 3 +++
2 files changed, 21 insertions(+)
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 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m)
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 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m)
u32 chconf;
spi = m->spi;
+ master = spi->master;
cs = spi->controller_state;
cd = spi->controller_data;
@@ -952,6 +954,14 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m)
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 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m)
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;
diff --git a/include/linux/platform_data/spi-omap2-mcspi.h b/include/linux/platform_data/spi-omap2-mcspi.h
index a65572d..c100456 100644
--- a/include/linux/platform_data/spi-omap2-mcspi.h
+++ b/include/linux/platform_data/spi-omap2-mcspi.h
@@ -22,6 +22,9 @@ struct omap2_mcspi_dev_attr {
struct omap2_mcspi_device_config {
unsigned turbo_mode:1;
+
+ /* toggle chip select after every word */
+ unsigned cs_per_word:1;
};
#endif
--
1.7.11.7
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
