From dffaf7439979e6dbb820633bb4f44dcadcac847e Mon Sep 17 00:00:00 2001 From: Miquel Raynal Date: Fri, 8 Nov 2019 15:07:42 +0100 Subject: 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 Link: https://lore.kernel.org/r/20191108140744.1734-6-miquel.raynal@bootlin.com Signed-off-by: Mark Brown --- drivers/spi/spi-zynq-qspi.c | 17 ++++++----------- 1 file 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); } -- cgit v1.2.3