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 | 34 ++++++++++++++++++++-------
include/linux/platform_data/spi-omap2-mcspi.h | 3 +++
2 files changed, 29 insertions(+), 8 deletions(-)
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index b610f52..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;
@@ -1020,7 +1038,7 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m)
}
static int omap2_mcspi_transfer_one_message(struct spi_master *master,
- struct spi_message *m)
+ struct spi_message *m)
{
struct omap2_mcspi *mcspi;
struct spi_transfer *t;
@@ -1041,7 +1059,7 @@ static int omap2_mcspi_transfer_one_message(struct spi_master *master,
|| (len && !(rx_buf || tx_buf))
|| (t->bits_per_word &&
( t->bits_per_word < 4
- || t->bits_per_word > 32))) {
+ || t->bits_per_word > 32))) {
dev_dbg(mcspi->dev, "transfer: %d Hz, %d %s%s, %d bpw\n",
t->speed_hz,
len,
@@ -1052,8 +1070,8 @@ static int omap2_mcspi_transfer_one_message(struct spi_master *master,
}
if (t->speed_hz && t->speed_hz < (OMAP2_MCSPI_MAX_FREQ >> 15)) {
dev_dbg(mcspi->dev, "speed_hz %d below minimum %d Hz\n",
- t->speed_hz,
- OMAP2_MCSPI_MAX_FREQ >> 15);
+ t->speed_hz,
+ OMAP2_MCSPI_MAX_FREQ >> 15);
return -EINVAL;
}
@@ -1099,7 +1117,7 @@ static int omap2_mcspi_master_setup(struct omap2_mcspi *mcspi)
return ret;
mcspi_write_reg(master, OMAP2_MCSPI_WAKEUPENABLE,
- OMAP2_MCSPI_WAKEUPENABLE_WKEN);
+ OMAP2_MCSPI_WAKEUPENABLE_WKEN);
ctx->wakeupenable = OMAP2_MCSPI_WAKEUPENABLE_WKEN;
omap2_mcspi_set_master_mode(master);
@@ -1228,7 +1246,7 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
sprintf(dma_ch_name, "rx%d", i);
dma_res = platform_get_resource_byname(pdev, IORESOURCE_DMA,
- dma_ch_name);
+ dma_ch_name);
if (!dma_res) {
dev_dbg(&pdev->dev, "cannot get DMA RX channel\n");
status = -ENODEV;
@@ -1238,7 +1256,7 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
mcspi->dma_channels[i].dma_rx_sync_dev = dma_res->start;
sprintf(dma_ch_name, "tx%d", i);
dma_res = platform_get_resource_byname(pdev, IORESOURCE_DMA,
- dma_ch_name);
+ dma_ch_name);
if (!dma_res) {
dev_dbg(&pdev->dev, "cannot get DMA TX channel\n");
status = -ENODEV;
@@ -1254,7 +1272,7 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
if (IS_ERR(pinctrl))
dev_warn(&pdev->dev,
- "pins are not configured from the driver\n");
+ "pins are not configured from the driver\n");
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
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
--
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