[U-Boot] [PATCH 7/7] spi: cadence_qspi: Support specifying the sample edge used

[Phil Edworthy]

The HW manual does not give details about what the register
value for this bit actually does, other than "Choose edge on
which data outputs from flash memory will be sampled".

Signed-off-by: Phil Edworthy <phil.edworthy at renesas.com>

---
Our HW engineers tell me that it needs to be set for our hardware.
---
 doc/device-tree-bindings/spi/spi-cadence.txt |  2 ++
 drivers/spi/cadence_qspi.c                   | 10 +++++++---
 drivers/spi/cadence_qspi.h                   |  3 ++-
 drivers/spi/cadence_qspi_apb.c               |  8 +++++++-
 4 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/doc/device-tree-bindings/spi/spi-cadence.txt b/doc/device-tree-bindings/spi/spi-cadence.txt
index c1e2233..71aa06a 100644
--- a/doc/device-tree-bindings/spi/spi-cadence.txt
+++ b/doc/device-tree-bindings/spi/spi-cadence.txt
@@ -26,3 +26,5 @@ connected flash properties
 			  select (n_ss_out).
 - tslch-ns		: Delay in master reference clocks between setting
 			  n_ss_out low and first bit transfer
+- sample-edge		: The edge on which data outputs from flash memory will
+			  be sampled.
diff --git a/drivers/spi/cadence_qspi.c b/drivers/spi/cadence_qspi.c
index 1051afb..afe7cb2 100644
--- a/drivers/spi/cadence_qspi.c
+++ b/drivers/spi/cadence_qspi.c
@@ -39,8 +39,10 @@ static int cadence_spi_write_speed(struct udevice *bus, uint hz)
 /* Calibration sequence to determine the read data capture delay register */
 static int spi_calibration(struct udevice *bus, uint hz)
 {
+	struct cadence_spi_platdata *plat = bus->platdata;
 	struct cadence_spi_priv *priv = dev_get_priv(bus);
 	void *base = priv->regbase;
+	unsigned int edge = plat->sample_edge;
 	u8 opcode_rdid = 0x9F;
 	unsigned int idcode = 0, temp = 0;
 	int err = 0, i, range_lo = -1, range_hi = -1;
@@ -49,7 +51,7 @@ static int spi_calibration(struct udevice *bus, uint hz)
 	cadence_spi_write_speed(bus, 1000000);
 
 	/* configure the read data capture delay register to 0 */
-	cadence_qspi_apb_readdata_capture(base, 1, 0);
+	cadence_qspi_apb_readdata_capture(base, 1, edge, 0);
 
 	/* Enable QSPI */
 	cadence_qspi_apb_controller_enable(base);
@@ -69,7 +71,7 @@ static int spi_calibration(struct udevice *bus, uint hz)
 		cadence_qspi_apb_controller_disable(base);
 
 		/* reconfigure the read data capture delay register */
-		cadence_qspi_apb_readdata_capture(base, 1, i);
+		cadence_qspi_apb_readdata_capture(base, 1, edge, i);
 
 		/* Enable back QSPI */
 		cadence_qspi_apb_controller_enable(base);
@@ -105,7 +107,8 @@ static int spi_calibration(struct udevice *bus, uint hz)
 	cadence_qspi_apb_controller_disable(base);
 
 	/* configure the final value for read data capture delay register */
-	cadence_qspi_apb_readdata_capture(base, 1, (range_hi + range_lo) / 2);
+	cadence_qspi_apb_readdata_capture(base, 1, edge,
+		(range_hi + range_lo) / 2);
 	debug("SF: Read data capture delay calibrated to %i (%i - %i)\n",
 	      (range_hi + range_lo) / 2, range_lo, range_hi);
 
@@ -318,6 +321,7 @@ static int cadence_spi_ofdata_to_platdata(struct udevice *bus)
 	plat->tchsh_ns = fdtdec_get_int(blob, subnode, "tchsh-ns", 20);
 	plat->tslch_ns = fdtdec_get_int(blob, subnode, "tslch-ns", 20);
 	plat->sram_size = fdtdec_get_int(blob, node, "sram-size", 128);
+	plat->sample_edge = fdtdec_get_int(blob, subnode, "sample-edge", 0);
 
 	debug("%s: regbase=%p ahbbase=%p max-frequency=%d page-size=%d\n",
 	      __func__, plat->regbase, plat->ahbbase, plat->max_hz,
diff --git a/drivers/spi/cadence_qspi.h b/drivers/spi/cadence_qspi.h
index a849f7b..3cd3b00 100644
--- a/drivers/spi/cadence_qspi.h
+++ b/drivers/spi/cadence_qspi.h
@@ -26,6 +26,7 @@ struct cadence_spi_platdata {
 	u32		tchsh_ns;
 	u32		tslch_ns;
 	u32		sram_size;
+	unsigned int	sample_edge;
 };
 
 struct cadence_spi_priv {
@@ -73,6 +74,6 @@ void cadence_qspi_apb_delay(void *reg_base,
 	unsigned int tchsh_ns, unsigned int tslch_ns);
 void cadence_qspi_apb_enter_xip(void *reg_base, char xip_dummy);
 void cadence_qspi_apb_readdata_capture(void *reg_base,
-	unsigned int bypass, unsigned int delay);
+	unsigned int bypass, unsigned int edge, unsigned int delay);
 
 #endif /* __CADENCE_QSPI_H__ */
diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
index 533274d..c43fde6 100644
--- a/drivers/spi/cadence_qspi_apb.c
+++ b/drivers/spi/cadence_qspi_apb.c
@@ -98,6 +98,7 @@
 #define	CQSPI_REG_RD_DATA_CAPTURE_BYPASS	BIT(0)
 #define	CQSPI_REG_RD_DATA_CAPTURE_DELAY_LSB	1
 #define	CQSPI_REG_RD_DATA_CAPTURE_DELAY_MASK	0xF
+#define	CQSPI_REG_RD_DATA_CAPTURE_EDGE		BIT(5)
 
 #define	CQSPI_REG_SIZE				0x14
 #define	CQSPI_REG_SIZE_ADDRESS_LSB		0
@@ -237,7 +238,7 @@ static unsigned int cadence_qspi_wait_idle(void *reg_base)
 }
 
 void cadence_qspi_apb_readdata_capture(void *reg_base,
-				unsigned int bypass, unsigned int delay)
+	unsigned int bypass, unsigned int edge, unsigned int delay)
 {
 	unsigned int reg;
 	cadence_qspi_apb_controller_disable(reg_base);
@@ -249,6 +250,11 @@ void cadence_qspi_apb_readdata_capture(void *reg_base,
 	else
 		reg &= ~CQSPI_REG_RD_DATA_CAPTURE_BYPASS;
 
+	if (edge)
+		reg |= CQSPI_REG_RD_DATA_CAPTURE_EDGE;
+	else
+		reg &= ~CQSPI_REG_RD_DATA_CAPTURE_EDGE;
+
 	reg &= ~(CQSPI_REG_RD_DATA_CAPTURE_DELAY_MASK
 		<< CQSPI_REG_RD_DATA_CAPTURE_DELAY_LSB);
 
-- 
2.5.0