[U-Boot] [PATCH V2 3/4] clk: imx: add i.MX8M composite clk support

[Peng Fan]

Import i.MX8M composite clk from Linux Kernel 5.3.0-rc2

Signed-off-by: Peng Fan <peng.fan at nxp.com>
---
 drivers/clk/imx/clk-composite-8m.c | 170 +++++++++++++++++++++++++++++++++++++
 1 file changed, 170 insertions(+)
 create mode 100644 drivers/clk/imx/clk-composite-8m.c

diff --git a/drivers/clk/imx/clk-composite-8m.c b/drivers/clk/imx/clk-composite-8m.c
new file mode 100644
index 0000000000..57ebbc3bb0
--- /dev/null
+++ b/drivers/clk/imx/clk-composite-8m.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 NXP
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <malloc.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <linux/clk-provider.h>
+#include <clk.h>
+#include "clk.h"
+
+#define UBOOT_DM_CLK_IMX_COMPOSITE "imx_clk_composite"
+
+#define PCG_PREDIV_SHIFT	16
+#define PCG_PREDIV_WIDTH	3
+#define PCG_PREDIV_MAX		8
+
+#define PCG_DIV_SHIFT		0
+#define PCG_DIV_WIDTH		6
+#define PCG_DIV_MAX		64
+
+#define PCG_PCS_SHIFT		24
+#define PCG_PCS_MASK		0x7
+
+#define PCG_CGC_SHIFT		28
+
+static unsigned long imx8m_clk_composite_divider_recalc_rate(struct clk *clk)
+{
+	struct clk_divider *divider = (struct clk_divider *)to_clk_divider(clk);
+	struct clk_composite *composite = (struct clk_composite *)clk->data;
+	ulong parent_rate = clk_get_parent_rate(&composite->clk);
+	unsigned long prediv_rate;
+	unsigned int prediv_value;
+	unsigned int div_value;
+
+	debug("%s: name %s prate: %lu reg: %p\n", __func__,
+	      (&composite->clk)->dev->name, parent_rate, divider->reg);
+	prediv_value = readl(divider->reg) >> divider->shift;
+	prediv_value &= clk_div_mask(divider->width);
+
+	prediv_rate = divider_recalc_rate(clk, parent_rate, prediv_value,
+					  NULL, divider->flags,
+					  divider->width);
+
+	div_value = readl(divider->reg) >> PCG_DIV_SHIFT;
+	div_value &= clk_div_mask(PCG_DIV_WIDTH);
+
+	return divider_recalc_rate(clk, prediv_rate, div_value, NULL,
+				   divider->flags, PCG_DIV_WIDTH);
+}
+
+static int imx8m_clk_composite_compute_dividers(unsigned long rate,
+						unsigned long parent_rate,
+						int *prediv, int *postdiv)
+{
+	int div1, div2;
+	int error = INT_MAX;
+	int ret = -EINVAL;
+
+	*prediv = 1;
+	*postdiv = 1;
+
+	for (div1 = 1; div1 <= PCG_PREDIV_MAX; div1++) {
+		for (div2 = 1; div2 <= PCG_DIV_MAX; div2++) {
+			int new_error = ((parent_rate / div1) / div2) - rate;
+
+			if (abs(new_error) < abs(error)) {
+				*prediv = div1;
+				*postdiv = div2;
+				error = new_error;
+				ret = 0;
+			}
+		}
+	}
+	return ret;
+}
+
+/*
+ * The clk are not binded to a dev, because it is part of composite clk
+ * use composite clk to get dev
+ */
+static ulong imx8m_clk_composite_divider_set_rate(struct clk *clk,
+						  unsigned long rate)
+{
+	struct clk_divider *divider = (struct clk_divider *)to_clk_divider(clk);
+	struct clk_composite *composite = (struct clk_composite *)clk->data;
+	ulong parent_rate = clk_get_parent_rate(&composite->clk);
+	int prediv_value;
+	int div_value;
+	int ret;
+	u32 val;
+
+	ret = imx8m_clk_composite_compute_dividers(rate, parent_rate,
+						   &prediv_value, &div_value);
+	if (ret)
+		return -EINVAL;
+
+	val = readl(divider->reg);
+	val &= ~((clk_div_mask(divider->width) << divider->shift) |
+			(clk_div_mask(PCG_DIV_WIDTH) << PCG_DIV_SHIFT));
+
+	val |= (u32)(prediv_value  - 1) << divider->shift;
+	val |= (u32)(div_value - 1) << PCG_DIV_SHIFT;
+	writel(val, divider->reg);
+
+	return clk_get_rate(&composite->clk);
+}
+
+static const struct clk_ops imx8m_clk_composite_divider_ops = {
+	.get_rate = imx8m_clk_composite_divider_recalc_rate,
+	.set_rate = imx8m_clk_composite_divider_set_rate,
+};
+
+struct clk *imx8m_clk_composite_flags(const char *name,
+				      const char * const *parent_names,
+				      int num_parents, void __iomem *reg,
+				      unsigned long flags)
+{
+	struct clk *clk = ERR_PTR(-ENOMEM);
+	struct clk_divider *div = NULL;
+	struct clk_gate *gate = NULL;
+	struct clk_mux *mux = NULL;
+
+	mux = kzalloc(sizeof(*mux), GFP_KERNEL);
+	if (!mux)
+		goto fail;
+
+	mux->reg = reg;
+	mux->shift = PCG_PCS_SHIFT;
+	mux->mask = PCG_PCS_MASK;
+	mux->num_parents = num_parents;
+	mux->flags = flags;
+	mux->parent_names = parent_names;
+
+	div = kzalloc(sizeof(*div), GFP_KERNEL);
+	if (!div)
+		goto fail;
+
+	div->reg = reg;
+	div->shift = PCG_PREDIV_SHIFT;
+	div->width = PCG_PREDIV_WIDTH;
+	div->flags = CLK_DIVIDER_ROUND_CLOSEST | flags;
+
+	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
+	if (!gate)
+		goto fail;
+
+	gate->reg = reg;
+	gate->bit_idx = PCG_CGC_SHIFT;
+	gate->flags = flags;
+
+	clk = clk_register_composite(NULL, name,
+				     parent_names, num_parents,
+				     &mux->clk, &clk_mux_ops, &div->clk,
+				     &imx8m_clk_composite_divider_ops,
+				     &gate->clk, &clk_gate_ops, flags);
+	if (IS_ERR(clk))
+		goto fail;
+
+	return clk;
+
+fail:
+	kfree(gate);
+	kfree(div);
+	kfree(mux);
+	return ERR_CAST(clk);
+}
-- 
2.16.4