[U-Boot] [PATCH v5 2/2] DW SPI: Get clock value from Device Tree

[Eugeniy Paltsev]

Add option to set spi controller clock frequency via device tree
using standard clock bindings.

Define dw_spi_get_clk function as 'weak' as some targets
(like SOCFPGA_GEN5 and SOCFPGA_ARRIA10) don't use standard clock API
and implement dw_spi_get_clk their own way in their clock manager.

Get rid of clock_manager.h include as we don't use
cm_get_spi_controller_clk_hz function anymore. (we use redefined
dw_spi_get_clk in SOCFPGA clock managers instead)

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev at synopsys.com>
---
 drivers/spi/designware_spi.c | 42 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c
index 6cc4f51..470a3a7 100644
--- a/drivers/spi/designware_spi.c
+++ b/drivers/spi/designware_spi.c
@@ -12,6 +12,7 @@
 
 #include <asm-generic/gpio.h>
 #include <common.h>
+#include <clk.h>
 #include <dm.h>
 #include <errno.h>
 #include <malloc.h>
@@ -19,7 +20,6 @@
 #include <fdtdec.h>
 #include <linux/compat.h>
 #include <asm/io.h>
-#include <asm/arch/clock_manager.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -95,6 +95,7 @@ struct dw_spi_priv {
 	void __iomem *regs;
 	unsigned int freq;		/* Default frequency */
 	unsigned int mode;
+	unsigned long bus_clk_rate;
 
 	struct gpio_desc cs_gpio;	/* External chip-select gpio */
 
@@ -195,14 +196,51 @@ static void spi_hw_init(struct dw_spi_priv *priv)
 	debug("%s: fifo_len=%d\n", __func__, priv->fifo_len);
 }
 
+/*
+ * We define dw_spi_get_clk function as 'weak' as some targets
+ * (like SOCFPGA_GEN5 and SOCFPGA_ARRIA10) fon't use standard clock API
+ * and implement dw_spi_get_clk their own way in their clock manager.
+ */
+__weak int dw_spi_get_clk(struct udevice *bus, ulong *rate)
+{
+	struct clk clk;
+	int ret;
+
+	ret = clk_get_by_index(bus, 0, &clk);
+	if (ret)
+		return -EINVAL;
+
+	ret = clk_enable(&clk);
+	if (ret && ret != -ENOSYS)
+		return ret;
+
+	*rate = clk_get_rate(&clk);
+	if (!*rate) {
+		clk_disable(&clk);
+		return -EINVAL;
+	}
+
+	debug("%s: get spi controller clk via device tree: %lu Hz\n",
+	      __func__, *rate);
+
+	clk_free(&clk);
+
+	return 0;
+}
+
 static int dw_spi_probe(struct udevice *bus)
 {
 	struct dw_spi_platdata *plat = dev_get_platdata(bus);
 	struct dw_spi_priv *priv = dev_get_priv(bus);
+	int ret;
 
 	priv->regs = plat->regs;
 	priv->freq = plat->frequency;
 
+	ret = dw_spi_get_clk(bus, &priv->bus_clk_rate);
+	if (ret)
+		return ret;
+
 	/* Currently only bits_per_word == 8 supported */
 	priv->bits_per_word = 8;
 
@@ -411,7 +449,7 @@ static int dw_spi_set_speed(struct udevice *bus, uint speed)
 	spi_enable_chip(priv, 0);
 
 	/* clk_div doesn't support odd number */
-	clk_div = cm_get_spi_controller_clk_hz() / speed;
+	clk_div = priv->bus_clk_rate / speed;
 	clk_div = (clk_div + 1) & 0xfffe;
 	dw_write(priv, DW_SPI_BAUDR, clk_div);
 
-- 
2.9.3