[PATCH linux-next 2/2] clk: bcm6345: Add BCM6345 gated clock support

[Simon Arlott <simon@fire.lp0.eu>]

The BCM6345 contains clocks gated with a register. Clocks are indexed
by bits in the register and are active high. Clock gate bits are
interleaved with other status bits and configurable clocks in the same
register.

Enabled by default for BMIPS_GENERIC.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
---
Renamed to BCM6345.

 MAINTAINERS                   |   1 +
 drivers/clk/bcm/Kconfig       |   9 ++
 drivers/clk/bcm/Makefile      |   1 +
 drivers/clk/bcm/clk-bcm6345.c | 191 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 202 insertions(+)
 create mode 100644 drivers/clk/bcm/clk-bcm6345.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 577e5ea..9a61f48 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2381,6 +2381,7 @@ F:	arch/mips/bmips/*
 F:	arch/mips/include/asm/mach-bmips/*
 F:	arch/mips/kernel/*bmips*
 F:	arch/mips/boot/dts/brcm/bcm*.dts*
+F:	drivers/clk/bcm/clk-bcm6345*
 F:	drivers/irqchip/irq-bcm63*
 F:	drivers/irqchip/irq-bcm7*
 F:	drivers/irqchip/irq-brcmstb*
diff --git a/drivers/clk/bcm/Kconfig b/drivers/clk/bcm/Kconfig
index f287845..043353a 100644
--- a/drivers/clk/bcm/Kconfig
+++ b/drivers/clk/bcm/Kconfig
@@ -8,6 +8,15 @@ config CLK_BCM_63XX
 	  Enable common clock framework support for Broadcom BCM63xx DSL SoCs
 	  based on the ARM architecture
 
+config CLK_BCM_6345
+	bool "Broadcom BCM6345 clock support"
+	depends on BMIPS_GENERIC || COMPILE_TEST
+	depends on COMMON_CLK
+	default BMIPS_GENERIC
+	help
+	  Enable common clock framework support for Broadcom BCM6345 DSL SoCs
+	  based on the MIPS architecture
+
 config CLK_BCM_KONA
 	bool "Broadcom Kona CCU clock support"
 	depends on ARCH_BCM_MOBILE || COMPILE_TEST
diff --git a/drivers/clk/bcm/Makefile b/drivers/clk/bcm/Makefile
index 247c267..e2bac43 100644
--- a/drivers/clk/bcm/Makefile
+++ b/drivers/clk/bcm/Makefile
@@ -1,4 +1,5 @@
 obj-$(CONFIG_CLK_BCM_63XX)	+= clk-bcm63xx.o
+obj-$(CONFIG_CLK_BCM_6345)	+= clk-bcm6345.o
 obj-$(CONFIG_CLK_BCM_KONA)	+= clk-kona.o
 obj-$(CONFIG_CLK_BCM_KONA)	+= clk-kona-setup.o
 obj-$(CONFIG_CLK_BCM_KONA)	+= clk-bcm281xx.o
diff --git a/drivers/clk/bcm/clk-bcm6345.c b/drivers/clk/bcm/clk-bcm6345.c
new file mode 100644
index 0000000..88a1e7e
--- /dev/null
+++ b/drivers/clk/bcm/clk-bcm6345.c
@@ -0,0 +1,191 @@
+/*
+ * Copyright 2015 Simon Arlott
+ *
+ * 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.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Derived from clk-gate.c:
+ * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
+ * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+/**
+ * DOC: Basic clock which uses a bit in a regmap to gate and ungate the output
+ *
+ * Traits of this clock:
+ * prepare - clk_(un)prepare only ensures parent is (un)prepared
+ * enable - clk_enable and clk_disable are functional & control gating
+ * rate - inherits rate from parent.  No clk_set_rate support
+ * parent - fixed parent.  No clk_set_parent support
+ */
+
+struct clk_bcm6345 {
+	struct clk_hw hw;
+	struct regmap *map;
+	u32 offset;
+	u32 mask;
+};
+
+#define to_clk_bcm6345(_hw) container_of(_hw, struct clk_bcm6345, hw)
+
+static int clk_bcm6345_enable(struct clk_hw *hw)
+{
+	struct clk_bcm6345 *gate = to_clk_bcm6345(hw);
+
+	return regmap_write_bits(gate->map, gate->offset,
+					gate->mask, gate->mask);
+}
+
+static void clk_bcm6345_disable(struct clk_hw *hw)
+{
+	struct clk_bcm6345 *gate = to_clk_bcm6345(hw);
+
+	regmap_write_bits(gate->map, gate->offset,
+					gate->mask, 0);
+}
+
+static int clk_bcm6345_is_enabled(struct clk_hw *hw)
+{
+	struct clk_bcm6345 *gate = to_clk_bcm6345(hw);
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(gate->map, gate->offset, &val);
+	if (ret)
+		return ret;
+
+	val &= gate->mask;
+
+	return val ? 1 : 0;
+}
+
+const struct clk_ops clk_bcm6345_ops = {
+	.enable = clk_bcm6345_enable,
+	.disable = clk_bcm6345_disable,
+	.is_enabled = clk_bcm6345_is_enabled,
+};
+
+static struct clk * __init of_bcm6345_clk_register(const char *parent_name,
+	const char *clk_name, struct regmap *map, u32 offset, u32 mask)
+{
+	struct clk_bcm6345 *gate;
+	struct clk_init_data init;
+	struct clk *ret;
+
+	gate = kzalloc(sizeof(*gate), GFP_KERNEL);
+	if (!gate)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = clk_name;
+	init.ops = &clk_bcm6345_ops;
+	init.flags = CLK_IS_BASIC;
+	init.parent_names = (parent_name ? &parent_name : NULL);
+	init.num_parents = (parent_name ? 1 : 0);
+	gate->hw.init = &init;
+	gate->map = map;
+	gate->offset = offset;
+	gate->mask = mask;
+
+	ret = clk_register(NULL, &gate->hw);
+	if (IS_ERR(ret))
+		kfree(gate);
+
+	return ret;
+}
+
+static void __init of_bcm6345_clk_setup(struct device_node *node)
+{
+	struct clk_onecell_data *clk_data;
+	const char *parent_name = NULL;
+	struct regmap *map;
+	u32 offset;
+	unsigned int clocks = 0;
+	int i;
+
+	clk_data = kzalloc(sizeof(*clk_data), GFP_KERNEL);
+	if (!clk_data)
+		return;
+
+	clk_data->clk_num = 32;
+	clk_data->clks = kmalloc_array(clk_data->clk_num,
+		sizeof(*clk_data->clks), GFP_KERNEL);
+
+	for (i = 0; i < clk_data->clk_num; i++)
+		clk_data->clks[i] = ERR_PTR(-ENODEV);
+
+	if (of_clk_get_parent_count(node) > 0)
+		parent_name = of_clk_get_parent_name(node, 0);
+
+	map = syscon_regmap_lookup_by_phandle(node, "regmap");
+	if (IS_ERR(map)) {
+		pr_err("%s: regmap lookup error %ld\n",
+			node->full_name, PTR_ERR(map));
+		goto out;
+	}
+
+	if (of_property_read_u32(node, "offset", &offset)) {
+		pr_err("%s: offset not specified\n", node->full_name);
+		goto out;
+	}
+
+	/* clks[] is sparse, indexed by bit, maximum clocks checked using i */
+	for (i = 0; i < clk_data->clk_num; i++) {
+		u32 bit;
+		const char *clk_name;
+
+		if (of_property_read_u32_index(node, "clock-indices",
+				i, &bit))
+			goto out;
+
+		if (of_property_read_string_index(node, "clock-output-names",
+				i, &clk_name))
+			goto out;
+
+		if (bit >= clk_data->clk_num) {
+			pr_err("%s: clock bit %u out of range\n",
+				node->full_name, bit);
+			continue;
+		}
+
+		if (!IS_ERR(clk_data->clks[bit])) {
+			pr_err("%s: clock bit %u already exists\n",
+				node->full_name, bit);
+			continue;
+		}
+
+		clk_data->clks[bit] = of_bcm6345_clk_register(parent_name,
+					clk_name, map, offset, BIT(bit));
+		if (!IS_ERR(clk_data->clks[bit]))
+			clocks++;
+	}
+
+out:
+	if (clocks) {
+		of_clk_add_provider(node, of_clk_src_onecell_get, clk_data);
+		pr_info("%s: registered %u clocks\n", node->name, clocks);
+	} else {
+		kfree(clk_data->clks);
+		kfree(clk_data);
+	}
+}
+
+CLK_OF_DECLARE(bcm6345_clk, "brcm,bcm6345-gate-clk", of_bcm6345_clk_setup);
-- 
2.1.4

-- 
Simon Arlott