mmc: spi: Pull out the SSP clock configuration function

Pull out the MMC clock configuration function and make it
into SSP clock configuration function, so it can be used by
the SPI driver too.

Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Chris Ball <cjb@laptop.org>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

2 files changed, 63 insertions, 1 deletions

diff --git a/drivers/clk/mxs/Makefile b/drivers/clk/mxs/Makefile
index 7bedeec0852..a6a22237e86 100644
--- a/drivers/clk/mxs/Makefile
+++ b/drivers/clk/mxs/Makefile
@@ -2,7 +2,7 @@
 # Makefile for mxs specific clk
 #
 
-obj-y += clk.o clk-pll.o clk-ref.o clk-div.o clk-frac.o
+obj-y += clk.o clk-pll.o clk-ref.o clk-div.o clk-frac.o clk-ssp.o
 
 obj-$(CONFIG_SOC_IMX23) += clk-imx23.o
 obj-$(CONFIG_SOC_IMX28) += clk-imx28.o
diff --git a/drivers/clk/mxs/clk-ssp.c b/drivers/clk/mxs/clk-ssp.c
new file mode 100644
index 00000000000..af7bdbf9ebd
--- /dev/null
+++ b/drivers/clk/mxs/clk-ssp.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright 2012 DENX Software Engineering, GmbH
+ *
+ * Pulled from code:
+ * Portions copyright (C) 2003 Russell King, PXA MMCI Driver
+ * Portions copyright (C) 2004-2005 Pierre Ossman, W83L51xD SD/MMC driver
+ *
+ * Copyright 2008 Embedded Alley Solutions, Inc.
+ * Copyright 2009-2011 Freescale Semiconductor, Inc.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/spi/mxs-spi.h>
+
+void mxs_ssp_set_clk_rate(struct mxs_ssp *ssp, unsigned int rate)
+{
+	unsigned int ssp_clk, ssp_sck;
+	u32 clock_divide, clock_rate;
+	u32 val;
+
+	ssp_clk = clk_get_rate(ssp->clk);
+
+	for (clock_divide = 2; clock_divide <= 254; clock_divide += 2) {
+		clock_rate = DIV_ROUND_UP(ssp_clk, rate * clock_divide);
+		clock_rate = (clock_rate > 0) ? clock_rate - 1 : 0;
+		if (clock_rate <= 255)
+			break;
+	}
+
+	if (clock_divide > 254) {
+		dev_err(ssp->dev,
+			"%s: cannot set clock to %d\n", __func__, rate);
+		return;
+	}
+
+	ssp_sck = ssp_clk / clock_divide / (1 + clock_rate);
+
+	val = readl(ssp->base + HW_SSP_TIMING(ssp));
+	val &= ~(BM_SSP_TIMING_CLOCK_DIVIDE | BM_SSP_TIMING_CLOCK_RATE);
+	val |= BF_SSP(clock_divide, TIMING_CLOCK_DIVIDE);
+	val |= BF_SSP(clock_rate, TIMING_CLOCK_RATE);
+	writel(val, ssp->base + HW_SSP_TIMING(ssp));
+
+	ssp->clk_rate = ssp_sck;
+
+	dev_dbg(ssp->dev,
+		"%s: clock_divide %d, clock_rate %d, ssp_clk %d, rate_actual %d, rate_requested %d\n",
+		__func__, clock_divide, clock_rate, ssp_clk, ssp_sck, rate);
+}
+EXPORT_SYMBOL_GPL(mxs_ssp_set_clk_rate);