1 files changed, 284 insertions, 0 deletions
diff --git a/drivers/clk/shmobile/clk-div6.c b/drivers/clk/shmobile/clk-div6.c
new file mode 100644
index 000000000..036a692c7
--- /dev/null
+++ b/drivers/clk/shmobile/clk-div6.c
@@ -0,0 +1,284 @@
+/*
+ * r8a7790 Common Clock Framework support
+ *
+ * Copyright (C) 2013  Renesas Solutions Corp.
+ *
+ * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+#define CPG_DIV6_CKSTP		BIT(8)
+#define CPG_DIV6_DIV(d)		((d) & 0x3f)
+#define CPG_DIV6_DIV_MASK	0x3f
+
+/**
+ * struct div6_clock - CPG 6 bit divider clock
+ * @hw: handle between common and hardware-specific interfaces
+ * @reg: IO-remapped register
+ * @div: divisor value (1-64)
+ */
+struct div6_clock {
+	struct clk_hw hw;
+	void __iomem *reg;
+	unsigned int div;
+	u32 src_shift;
+	u32 src_width;
+	u8 *parents;
+};
+
+#define to_div6_clock(_hw) container_of(_hw, struct div6_clock, hw)
+
+static int cpg_div6_clock_enable(struct clk_hw *hw)
+{
+	struct div6_clock *clock = to_div6_clock(hw);
+	u32 val;
+
+	val = (clk_readl(clock->reg) & ~(CPG_DIV6_DIV_MASK | CPG_DIV6_CKSTP))
+	    | CPG_DIV6_DIV(clock->div - 1);
+	clk_writel(val, clock->reg);
+
+	return 0;
+}
+
+static void cpg_div6_clock_disable(struct clk_hw *hw)
+{
+	struct div6_clock *clock = to_div6_clock(hw);
+	u32 val;
+
+	val = clk_readl(clock->reg);
+	val |= CPG_DIV6_CKSTP;
+	/*
+	 * DIV6 clocks require the divisor field to be non-zero when stopping
+	 * the clock. However, some clocks (e.g. ZB on sh73a0) fail to be
+	 * re-enabled later if the divisor field is changed when stopping the
+	 * clock
+	 */
+	if (!(val & CPG_DIV6_DIV_MASK))
+		val |= CPG_DIV6_DIV_MASK;
+	clk_writel(val, clock->reg);
+}
+
+static int cpg_div6_clock_is_enabled(struct clk_hw *hw)
+{
+	struct div6_clock *clock = to_div6_clock(hw);
+
+	return !(clk_readl(clock->reg) & CPG_DIV6_CKSTP);
+}
+
+static unsigned long cpg_div6_clock_recalc_rate(struct clk_hw *hw,
+						unsigned long parent_rate)
+{
+	struct div6_clock *clock = to_div6_clock(hw);
+	unsigned int div = (clk_readl(clock->reg) & CPG_DIV6_DIV_MASK) + 1;
+
+	return parent_rate / div;
+}
+
+static unsigned int cpg_div6_clock_calc_div(unsigned long rate,
+					    unsigned long parent_rate)
+{
+	unsigned int div;
+
+	if (!rate)
+		rate = 1;
+
+	div = DIV_ROUND_CLOSEST(parent_rate, rate);
+	return clamp_t(unsigned int, div, 1, 64);
+}
+
+static long cpg_div6_clock_round_rate(struct clk_hw *hw, unsigned long rate,
+				      unsigned long *parent_rate)
+{
+	unsigned int div = cpg_div6_clock_calc_div(rate, *parent_rate);
+
+	return *parent_rate / div;
+}
+
+static int cpg_div6_clock_set_rate(struct clk_hw *hw, unsigned long rate,
+				   unsigned long parent_rate)
+{
+	struct div6_clock *clock = to_div6_clock(hw);
+	unsigned int div = cpg_div6_clock_calc_div(rate, parent_rate);
+	u32 val;
+
+	clock->div = div;
+
+	val = clk_readl(clock->reg) & ~CPG_DIV6_DIV_MASK;
+	/* Only program the new divisor if the clock isn't stopped. */
+	if (!(val & CPG_DIV6_CKSTP))
+		clk_writel(val | CPG_DIV6_DIV(clock->div - 1), clock->reg);
+
+	return 0;
+}
+
+static u8 cpg_div6_clock_get_parent(struct clk_hw *hw)
+{
+	struct div6_clock *clock = to_div6_clock(hw);
+	unsigned int i;
+	u8 hw_index;
+
+	if (clock->src_width == 0)
+		return 0;
+
+	hw_index = (clk_readl(clock->reg) >> clock->src_shift) &
+		   (BIT(clock->src_width) - 1);
+	for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
+		if (clock->parents[i] == hw_index)
+			return i;
+	}
+
+	pr_err("%s: %s DIV6 clock set to invalid parent %u\n",
+	       __func__, __clk_get_name(hw->clk), hw_index);
+	return 0;
+}
+
+static int cpg_div6_clock_set_parent(struct clk_hw *hw, u8 index)
+{
+	struct div6_clock *clock = to_div6_clock(hw);
+	u8 hw_index;
+	u32 mask;
+
+	if (index >= __clk_get_num_parents(hw->clk))
+		return -EINVAL;
+
+	mask = ~((BIT(clock->src_width) - 1) << clock->src_shift);
+	hw_index = clock->parents[index];
+
+	clk_writel((clk_readl(clock->reg) & mask) |
+		(hw_index << clock->src_shift), clock->reg);
+
+	return 0;
+}
+
+static const struct clk_ops cpg_div6_clock_ops = {
+	.enable = cpg_div6_clock_enable,
+	.disable = cpg_div6_clock_disable,
+	.is_enabled = cpg_div6_clock_is_enabled,
+	.get_parent = cpg_div6_clock_get_parent,
+	.set_parent = cpg_div6_clock_set_parent,
+	.recalc_rate = cpg_div6_clock_recalc_rate,
+	.round_rate = cpg_div6_clock_round_rate,
+	.set_rate = cpg_div6_clock_set_rate,
+};
+
+static void __init cpg_div6_clock_init(struct device_node *np)
+{
+	unsigned int num_parents, valid_parents;
+	const char **parent_names;
+	struct clk_init_data init;
+	struct div6_clock *clock;
+	const char *name;
+	struct clk *clk;
+	unsigned int i;
+	int ret;
+
+	clock = kzalloc(sizeof(*clock), GFP_KERNEL);
+	if (!clock)
+		return;
+
+	num_parents = of_clk_get_parent_count(np);
+	if (num_parents < 1) {
+		pr_err("%s: no parent found for %s DIV6 clock\n",
+		       __func__, np->name);
+		return;
+	}
+
+	clock->parents = kmalloc_array(num_parents, sizeof(*clock->parents),
+		GFP_KERNEL);
+	parent_names = kmalloc_array(num_parents, sizeof(*parent_names),
+				GFP_KERNEL);
+	if (!parent_names)
+		return;
+
+	/* Remap the clock register and read the divisor. Disabling the
+	 * clock overwrites the divisor, so we need to cache its value for the
+	 * enable operation.
+	 */
+	clock->reg = of_iomap(np, 0);
+	if (clock->reg == NULL) {
+		pr_err("%s: failed to map %s DIV6 clock register\n",
+		       __func__, np->name);
+		goto error;
+	}
+
+	clock->div = (clk_readl(clock->reg) & CPG_DIV6_DIV_MASK) + 1;
+
+	/* Parse the DT properties. */
+	ret = of_property_read_string(np, "clock-output-names", &name);
+	if (ret < 0) {
+		pr_err("%s: failed to get %s DIV6 clock output name\n",
+		       __func__, np->name);
+		goto error;
+	}
+
+
+	for (i = 0, valid_parents = 0; i < num_parents; i++) {
+		const char *name = of_clk_get_parent_name(np, i);
+
+		if (name) {
+			parent_names[valid_parents] = name;
+			clock->parents[valid_parents] = i;
+			valid_parents++;
+		}
+	}
+
+	switch (num_parents) {
+	case 1:
+		/* fixed parent clock */
+		clock->src_shift = clock->src_width = 0;
+		break;
+	case 4:
+		/* clock with EXSRC bits 6-7 */
+		clock->src_shift = 6;
+		clock->src_width = 2;
+		break;
+	case 8:
+		/* VCLK with EXSRC bits 12-14 */
+		clock->src_shift = 12;
+		clock->src_width = 3;
+		break;
+	default:
+		pr_err("%s: invalid number of parents for DIV6 clock %s\n",
+		       __func__, np->name);
+		goto error;
+	}
+
+	/* Register the clock. */
+	init.name = name;
+	init.ops = &cpg_div6_clock_ops;
+	init.flags = CLK_IS_BASIC;
+	init.parent_names = parent_names;
+	init.num_parents = valid_parents;
+
+	clock->hw.init = &init;
+
+	clk = clk_register(NULL, &clock->hw);
+	if (IS_ERR(clk)) {
+		pr_err("%s: failed to register %s DIV6 clock (%ld)\n",
+		       __func__, np->name, PTR_ERR(clk));
+		goto error;
+	}
+
+	of_clk_add_provider(np, of_clk_src_simple_get, clk);
+
+	kfree(parent_names);
+	return;
+
+error:
+	if (clock->reg)
+		iounmap(clock->reg);
+	kfree(parent_names);
+	kfree(clock);
+}
+CLK_OF_DECLARE(cpg_div6_clk, "renesas,cpg-div6-clock", cpg_div6_clock_init);