[PATCH] spi: zynq_spi: Use clk subsystem to get reference spi clk

[Michal Simek]

From: T Karthik Reddy <t.karthik.reddy at xilinx.com>

Remove fixed reference clk used by plat->frequency and use clk
subsystem to get reference clk. As per spi dt bindings
"spi-max-frequency" property should be used by the slave devices.
This property is read by spi-uclass driver for the slave device.
So avoid reading above property from the platform driver.

Signed-off-by: T Karthik Reddy <t.karthik.reddy at xilinx.com>
Signed-off-by: Michal Simek <michal.simek at xilinx.com>
---

 drivers/spi/zynq_spi.c | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/zynq_spi.c b/drivers/spi/zynq_spi.c
index 9923931e36ec..c26df182f6ba 100644
--- a/drivers/spi/zynq_spi.c
+++ b/drivers/spi/zynq_spi.c
@@ -12,6 +12,7 @@
 #include <malloc.h>
 #include <spi.h>
 #include <time.h>
+#include <clk.h>
 #include <asm/io.h>
 #include <linux/bitops.h>
 #include <linux/delay.h>
@@ -79,17 +80,10 @@ static int zynq_spi_ofdata_to_platdata(struct udevice *bus)
 
 	plat->regs = dev_read_addr_ptr(bus);
 
-	/* FIXME: Use 250MHz as a suitable default */
-	plat->frequency = fdtdec_get_int(blob, node, "spi-max-frequency",
-					250000000);
 	plat->deactivate_delay_us = fdtdec_get_int(blob, node,
 					"spi-deactivate-delay", 0);
 	plat->activate_delay_us = fdtdec_get_int(blob, node,
 						 "spi-activate-delay", 0);
-	plat->speed_hz = plat->frequency / 2;
-
-	debug("%s: regs=%p max-frequency=%d\n", __func__,
-	      plat->regs, plat->frequency);
 
 	return 0;
 }
@@ -128,13 +122,39 @@ static int zynq_spi_probe(struct udevice *bus)
 {
 	struct zynq_spi_platdata *plat = dev_get_platdata(bus);
 	struct zynq_spi_priv *priv = dev_get_priv(bus);
+	struct clk clk;
+	unsigned long clock;
+	int ret;
 
 	priv->regs = plat->regs;
 	priv->fifo_depth = ZYNQ_SPI_FIFO_DEPTH;
 
+	ret = clk_get_by_name(bus, "ref_clk", &clk);
+	if (ret < 0) {
+		dev_err(dev, "failed to get clock\n");
+		return ret;
+	}
+
+	clock = clk_get_rate(&clk);
+	if (IS_ERR_VALUE(clock)) {
+		dev_err(dev, "failed to get rate\n");
+		return clock;
+	}
+
+	ret = clk_enable(&clk);
+	if (ret && ret != -ENOSYS) {
+		dev_err(dev, "failed to enable clock\n");
+		return ret;
+	}
+
 	/* init the zynq spi hw */
 	zynq_spi_init_hw(priv);
 
+	plat->frequency = clock;
+	plat->speed_hz = plat->frequency / 2;
+
+	debug("%s: max-frequency=%d\n", __func__, plat->speed_hz);
+
 	return 0;
 }
 
-- 
2.28.0