clk: imx: Add clk-cpu support

Taken from the kernel as of 4.10-rc3. Needed for i.MX7

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

drivers/clk/imx/Makefile

@@ -5,6 +5,7 @@ obj-$(CONFIG_COMMON_CLK) +=	\
 	clk-pfd.o		\
 	clk-gate2.o		\
 	clk-gate-exclusive.o	\
+	clk-cpu.o		\
 	clk.o
 
 obj-$(CONFIG_ARCH_IMX1)   += clk-imx1.o

drivers/clk/imx/clk-cpu.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright (c) 2014 Lucas Stach <l.stach@pengutronix.de>, Pengutronix
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <common.h>
+#include <init.h>
+#include <driver.h>
+#include <linux/clk.h>
+#include <io.h>
+#include <linux/clkdev.h>
+#include <linux/err.h>
+#include <malloc.h>
+#include <clock.h>
+
+#include "clk.h"
+
+struct clk_cpu {
+	struct clk	clk;
+	struct clk	*div;
+	struct clk	*mux;
+	struct clk	*pll;
+	struct clk	*step;
+};
+
+static inline struct clk_cpu *to_clk_cpu(struct clk *clk)
+{
+	return container_of(clk, struct clk_cpu, clk);
+}
+
+static unsigned long clk_cpu_recalc_rate(struct clk *clk,
+					 unsigned long parent_rate)
+{
+	struct clk_cpu *cpu = to_clk_cpu(clk);
+
+	return clk_get_rate(cpu->div);
+}
+
+static long clk_cpu_round_rate(struct clk *clk, unsigned long rate,
+			       unsigned long *prate)
+{
+	struct clk_cpu *cpu = to_clk_cpu(clk);
+
+	return clk_round_rate(cpu->pll, rate);
+}
+
+static int clk_cpu_set_rate(struct clk *clk, unsigned long rate,
+			    unsigned long parent_rate)
+{
+	struct clk_cpu *cpu = to_clk_cpu(clk);
+	int ret;
+
+	/* switch to PLL bypass clock */
+	ret = clk_set_parent(cpu->mux, cpu->step);
+	if (ret)
+		return ret;
+
+	/* reprogram PLL */
+	ret = clk_set_rate(cpu->pll, rate);
+	if (ret) {
+		clk_set_parent(cpu->mux, cpu->pll);
+		return ret;
+	}
+	/* switch back to PLL clock */
+	clk_set_parent(cpu->mux, cpu->pll);
+
+	/* Ensure the divider is what we expect */
+	clk_set_rate(cpu->div, rate);
+
+	return 0;
+}
+
+static const struct clk_ops clk_cpu_ops = {
+	.recalc_rate	= clk_cpu_recalc_rate,
+	.round_rate	= clk_cpu_round_rate,
+	.set_rate	= clk_cpu_set_rate,
+};
+
+struct clk *imx_clk_cpu(const char *name, const char *parent_name,
+		struct clk *div, struct clk *mux, struct clk *pll,
+		struct clk *step)
+{
+	struct clk_cpu *cpu;
+	int ret;
+
+	cpu = xzalloc(sizeof(*cpu));
+
+	cpu->div = div;
+	cpu->mux = mux;
+	cpu->pll = pll;
+	cpu->step = step;
+
+	cpu->clk.name = name;
+	cpu->clk.ops = &clk_cpu_ops;
+	cpu->clk.flags = 0;
+	cpu->clk.parent_names = &parent_name;
+	cpu->clk.num_parents = 1;
+
+	ret = clk_register(&cpu->clk);
+	if (ret)
+		free(cpu);
+
+	return &cpu->clk;
+}

drivers/clk/imx/clk.h

@@ -125,5 +125,8 @@ struct clk *imx_clk_gate_exclusive(const char *name, const char *parent,
 
 void imx_check_clocks(struct clk *clks[], unsigned int count);
 
+struct clk *imx_clk_cpu(const char *name, const char *parent_name,
+		struct clk *div, struct clk *mux, struct clk *pll,
+		struct clk *step);
 
 #endif /* __IMX_CLK_H */