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authorMiquel Raynal <miquel.raynal@bootlin.com>2019-11-08 15:07:42 +0100
committerMark Brown <broonie@kernel.org>2019-11-08 17:44:30 +0000
commitdffaf7439979e6dbb820633bb4f44dcadcac847e (patch)
tree3b6930b2fc120f60986d480f7e698775006bc0bf /drivers/spi
parent044ac826200f08adebe3207a618d829279e9f3b1 (diff)
spi: zynq-qspi: Clarify the select chip function
The code used to assert and de-assert a chip select line is very complicated for no reason. Simplify the logic by either setting or resetting the concerned bit, which actually only changes an electrical state. Update the comment to reflect that there is no possibility to actually choose a CS as the default (CS0) will be driven in any case. Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Link: https://lore.kernel.org/r/20191108140744.1734-6-miquel.raynal@bootlin.com Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi-zynq-qspi.c17
1 files changed, 6 insertions, 11 deletions
diff --git a/drivers/spi/spi-zynq-qspi.c b/drivers/spi/spi-zynq-qspi.c
index 70ecefd817f7..80e51c894eaa 100644
--- a/drivers/spi/spi-zynq-qspi.c
+++ b/drivers/spi/spi-zynq-qspi.c
@@ -50,7 +50,6 @@
#define ZYNQ_QSPI_CONFIG_BDRATE_MASK GENMASK(5, 3) /* Baud Rate Mask */
#define ZYNQ_QSPI_CONFIG_CPHA_MASK BIT(2) /* Clock Phase Control */
#define ZYNQ_QSPI_CONFIG_CPOL_MASK BIT(1) /* Clock Polarity Control */
-#define ZYNQ_QSPI_CONFIG_SSCTRL_MASK BIT(10) /* Slave Select Mask */
#define ZYNQ_QSPI_CONFIG_FWIDTH_MASK GENMASK(7, 6) /* FIFO width */
#define ZYNQ_QSPI_CONFIG_MSTREN_MASK BIT(0) /* Master Mode */
@@ -62,7 +61,7 @@
*/
#define ZYNQ_QSPI_CONFIG_BAUD_DIV_MAX GENMASK(2, 0) /* Baud rate maximum */
#define ZYNQ_QSPI_CONFIG_BAUD_DIV_SHIFT 3 /* Baud rate divisor shift */
-#define ZYNQ_QSPI_CONFIG_PCS 10 /* Peripheral Chip Select */
+#define ZYNQ_QSPI_CONFIG_PCS BIT(10) /* Peripheral Chip Select */
/*
* QSPI Interrupt Registers bit Masks
@@ -287,16 +286,12 @@ static void zynq_qspi_chipselect(struct spi_device *spi, bool assert)
struct zynq_qspi *xqspi = spi_controller_get_devdata(ctlr);
u32 config_reg;
+ /* Ground the line to assert the CS */
config_reg = zynq_qspi_read(xqspi, ZYNQ_QSPI_CONFIG_OFFSET);
- if (assert) {
- /* Select the slave */
- config_reg &= ~ZYNQ_QSPI_CONFIG_SSCTRL_MASK;
- config_reg |= (((~(BIT(spi->chip_select))) <<
- ZYNQ_QSPI_CONFIG_PCS) &
- ZYNQ_QSPI_CONFIG_SSCTRL_MASK);
- } else {
- config_reg |= ZYNQ_QSPI_CONFIG_SSCTRL_MASK;
- }
+ if (assert)
+ config_reg &= ~ZYNQ_QSPI_CONFIG_PCS;
+ else
+ config_reg |= ZYNQ_QSPI_CONFIG_PCS;
zynq_qspi_write(xqspi, ZYNQ_QSPI_CONFIG_OFFSET, config_reg);
}