When the CS line is not connected, it is not needed to enable or
disable the chip selection functionality from the s3c64xx
devices in order to perform a transfer.
Set the CS controller logically always enabled already during
initialization (by writing '0' in the S3C64XX_SPI_SLAVE_SEL
register) and never disable it.
Signed-off-by: Andi Shyti <andi.sh...@samsung.com>
---
Documentation/devicetree/bindings/spi/spi-samsung.txt | 3 +++
drivers/spi/spi-s3c64xx.c | 9 ++++++++-
include/linux/platform_data/spi-s3c64xx.h | 1 +
3 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/spi/spi-samsung.txt
b/Documentation/devicetree/bindings/spi/spi-samsung.txt
index 6dbdeb3..930bc73 100644
--- a/Documentation/devicetree/bindings/spi/spi-samsung.txt
+++ b/Documentation/devicetree/bindings/spi/spi-samsung.txt
@@ -40,6 +40,9 @@ Optional Board Specific Properties:
- cs-gpios: should specify GPIOs used for chipselects (see spi-bus.txt)
+- no-cs-readback: the CS line is disconnected, therefore the device should not
+ operate based on CS signalling.
+
SPI Controller specific data in SPI slave nodes:
- The spi slave nodes should provide the following information which is
required
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 972367d..14269b0 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -315,6 +315,9 @@ static void s3c64xx_spi_set_cs(struct spi_device *spi, bool
enable)
struct s3c64xx_spi_driver_data *sdd =
spi_master_get_devdata(spi->master);
+ if (sdd->cntrlr_info->no_cs)
+ return;
+
if (enable) {
if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO)) {
writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
@@ -960,7 +963,9 @@ static void s3c64xx_spi_hwinit(struct
s3c64xx_spi_driver_data *sdd, int channel)
sdd->cur_speed = 0;
- if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO))
+ if (sci->no_cs)
+ writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL);
+ else if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_CS_AUTO))
writel(S3C64XX_SPI_SLAVE_SIG_INACT, sdd->regs +
S3C64XX_SPI_SLAVE_SEL);
/* Disable Interrupts - we use Polling if not DMA mode */
@@ -1015,6 +1020,8 @@ static struct s3c64xx_spi_info
*s3c64xx_spi_parse_dt(struct device *dev)
sci->num_cs = temp;
}
+ sci->no_cs = of_property_read_bool(dev->of_node, "broken-cs");
+
return sci;
}
#else
diff --git a/include/linux/platform_data/spi-s3c64xx.h
b/include/linux/platform_data/spi-s3c64xx.h
index fb5625b..5c1e21c 100644
--- a/include/linux/platform_data/spi-s3c64xx.h
+++ b/include/linux/platform_data/spi-s3c64xx.h
@@ -38,6 +38,7 @@ struct s3c64xx_spi_csinfo {
struct s3c64xx_spi_info {
int src_clk_nr;
int num_cs;
+ bool no_cs;
int (*cfg_gpio)(void);
dma_filter_fn filter;
void *dma_tx;
--
2.8.1
