clk: mvebu: add clock gating control provider for DT

This driver allows to provide DT clocks for clock gates found on
Marvell Dove and Kirkwood SoCs. The clock gates are referenced by
the phandle index of the corresponding bit in the clock gating control
register to ease lookup in the datasheet.

Signed-off-by: Sebastian Hesselbarth <[email protected]>

drivers/clk/mvebu/Kconfig

@@ -4,3 +4,5 @@ config MVEBU_CLK_CORE
 config MVEBU_CLK_CPU
        bool
 
+config MVEBU_CLK_GATING
+       bool

drivers/clk/mvebu/Makefile

@@ -1,2 +1,3 @@
 obj-$(CONFIG_MVEBU_CLK_CORE) 	+= clk.o clk-core.o
 obj-$(CONFIG_MVEBU_CLK_CPU) 	+= clk-cpu.o
+obj-$(CONFIG_MVEBU_CLK_GATING) 	+= clk-gating-ctrl.o

drivers/clk/mvebu/clk-gating-ctrl.c

@@ -0,0 +1,177 @@
+/*
+ * Marvell MVEBU clock gating control.
+ *
+ * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
+ * Andrew Lunn <andrew@lunn.ch>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/kernel.h>
+#include <linux/bitops.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/clk-provider.h>
+#include <linux/clk/mvebu.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+
+struct mvebu_gating_ctrl {
+	spinlock_t lock;
+	struct clk **gates;
+	int num_gates;
+};
+
+struct mvebu_soc_descr {
+	const char *name;
+	const char *parent;
+	int bit_idx;
+};
+
+#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)
+
+static struct clk __init *mvebu_clk_gating_get_src(
+	struct of_phandle_args *clkspec, void *data)
+{
+	struct mvebu_gating_ctrl *ctrl = (struct mvebu_gating_ctrl *)data;
+	int n;
+
+	if (clkspec->args_count < 1)
+		return ERR_PTR(-EINVAL);
+
+	for (n = 0; n < ctrl->num_gates; n++) {
+		struct clk_gate *gate =
+			to_clk_gate(__clk_get_hw(ctrl->gates[n]));
+		if (clkspec->args[0] == gate->bit_idx)
+			return ctrl->gates[n];
+	}
+	return ERR_PTR(-ENODEV);
+}
+
+static void __init mvebu_clk_gating_setup(
+	struct device_node *np, const struct mvebu_soc_descr *descr)
+{
+	struct mvebu_gating_ctrl *ctrl;
+	struct clk *clk;
+	void __iomem *base;
+	const char *default_parent = NULL;
+	int n;
+
+	base = of_iomap(np, 0);
+
+	clk = of_clk_get(np, 0);
+	if (!IS_ERR(clk)) {
+		default_parent = __clk_get_name(clk);
+		clk_put(clk);
+	}
+
+	ctrl = kzalloc(sizeof(struct mvebu_gating_ctrl), GFP_KERNEL);
+	if (WARN_ON(!ctrl))
+		return;
+
+	spin_lock_init(&ctrl->lock);
+
+	/*
+	 * Count, allocate, and register clock gates
+	 */
+	for (n = 0; descr[n].name;)
+		n++;
+
+	ctrl->num_gates = n;
+	ctrl->gates = kzalloc(ctrl->num_gates * sizeof(struct clk *),
+			      GFP_KERNEL);
+	if (WARN_ON(!ctrl->gates)) {
+		kfree(ctrl);
+		return;
+	}
+
+	for (n = 0; n < ctrl->num_gates; n++) {
+		const char *parent =
+			(descr[n].parent) ? descr[n].parent : default_parent;
+		ctrl->gates[n] = clk_register_gate(NULL, descr[n].name, parent,
+				   0, base, descr[n].bit_idx, 0, &ctrl->lock);
+		WARN_ON(IS_ERR(ctrl->gates[n]));
+	}
+	of_clk_add_provider(np, mvebu_clk_gating_get_src, ctrl);
+}
+
+/*
+ * SoC specific clock gating control
+ */
+
+#ifdef CONFIG_ARCH_DOVE
+static const struct mvebu_soc_descr __initconst dove_gating_descr[] = {
+	{ "usb0", NULL, 0 },
+	{ "usb1", NULL, 1 },
+	{ "ge", "gephy", 2 },
+	{ "sata", NULL, 3 },
+	{ "pex0", NULL, 4 },
+	{ "pex1", NULL, 5 },
+	{ "sdio0", NULL, 8 },
+	{ "sdio1", NULL, 9 },
+	{ "nand", NULL, 10 },
+	{ "camera", NULL, 11 },
+	{ "i2s0", NULL, 12 },
+	{ "i2s1", NULL, 13 },
+	{ "crypto", NULL, 15 },
+	{ "ac97", NULL, 21 },
+	{ "pdma", NULL, 22 },
+	{ "xor0", NULL, 23 },
+	{ "xor1", NULL, 24 },
+	{ "gephy", NULL, 30 },
+	{ }
+};
+#endif
+
+#ifdef CONFIG_ARCH_KIRKWOOD
+static const struct mvebu_soc_descr __initconst kirkwood_gating_descr[] = {
+	{ "ge0", NULL, 0 },
+	{ "pex0", NULL, 2 },
+	{ "usb0", NULL, 3 },
+	{ "sdio", NULL, 4 },
+	{ "tsu", NULL, 5 },
+	{ "runit", NULL, 7 },
+	{ "xor0", NULL, 8 },
+	{ "audio", NULL, 9 },
+	{ "sata0", NULL, 14 },
+	{ "sata1", NULL, 15 },
+	{ "xor1", NULL, 16 },
+	{ "crypto", NULL, 17 },
+	{ "pex1", NULL, 18 },
+	{ "ge1", NULL, 19 },
+	{ "tdm", NULL, 20 },
+	{ }
+};
+#endif
+
+static const __initdata struct of_device_id clk_gating_match[] = {
+#ifdef CONFIG_ARCH_DOVE
+	{
+		.compatible = "marvell,dove-gating-clock",
+		.data = dove_gating_descr,
+	},
+#endif
+
+#ifdef CONFIG_ARCH_KIRKWOOD
+	{
+		.compatible = "marvell,kirkwood-gating-clock",
+		.data = kirkwood_gating_descr,
+	},
+#endif
+
+	{ }
+};
+
+void __init mvebu_gating_clk_init(void)
+{
+	struct device_node *np;
+
+	for_each_matching_node(np, clk_gating_match) {
+		const struct of_device_id *match =
+			of_match_node(clk_gating_match, np);
+		mvebu_clk_gating_setup(np,
+		       (const struct mvebu_soc_descr *)match->data);
+	}
+}

drivers/clk/mvebu/clk-gating-ctrl.h

@@ -0,0 +1,22 @@
+/*
+ * Marvell EBU gating clock handling
+ *
+ * Copyright (C) 2012 Marvell
+ *
+ * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef __MVEBU_CLK_GATING_H
+#define __MVEBU_CLK_GATING_H
+
+#ifdef CONFIG_MVEBU_CLK_GATING
+void __init mvebu_gating_clk_init(void);
+#else
+void mvebu_gating_clk_init(void) {}
+#endif
+
+#endif

drivers/clk/mvebu/clk.c

@@ -17,9 +17,11 @@
 #include <linux/of.h>
 #include "clk-core.h"
 #include "clk-cpu.h"
+#include "clk-gating-ctrl.h"
 
 void __init mvebu_clocks_init(void)
 {
 	mvebu_core_clk_init();
+	mvebu_gating_clk_init();
 	mvebu_cpu_clk_init();
 }