clk: Add clock driver for AXM55xx SoC

Add clk driver to support clock blocks found on the AXM55xx devices. The driver
provides clock implementations for three different types of clock devices on
the AXM55xx device: PLL clock, a clock divider and a clock mux.
Signed-off-by: NAnders Berg <anders.berg@lsi.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: NMike Turquette <mturquette@linaro.org>

Documentation/devicetree/bindings/clock/lsi,axm5516-clks.txt

+AXM5516 clock driver bindings
+-----------------------------
+
+Required properties :
+- compatible : shall contain "lsi,axm5516-clks"
+- reg : shall contain base register location and length
+- #clock-cells : shall contain 1
+
+The consumer specifies the desired clock by having the clock ID in its "clocks"
+phandle cell. See <dt-bindings/clock/lsi,axxia-clock.h> for the list of
+supported clock IDs.
+
+Example:
+
+	clks: clock-controller@2010020000 {
+		compatible = "lsi,axm5516-clks";
+		#clock-cells = <1>;
+		reg = <0x20 0x10020000 0 0x20000>;
+	};
+
+	serial0: uart@2010080000 {
+		compatible = "arm,pl011", "arm,primecell";
+		reg = <0x20 0x10080000 0 0x1000>;
+		interrupts = <GIC_SPI 56 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&clks AXXIA_CLK_PER>;
+		clock-names = "apb_pclk";
+	};
+																																};
+

drivers/clk/Makefile

@@ -12,6 +12,7 @@ obj-$(CONFIG_COMMON_CLK)	+= clk-composite.o
 # hardware specific clock types
 # please keep this section sorted lexicographically by file/directory path name
 obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN)	+= clk-axi-clkgen.o
+obj-$(CONFIG_ARCH_AXXIA)		+= clk-axm5516.o
 obj-$(CONFIG_ARCH_BCM2835)		+= clk-bcm2835.o
 obj-$(CONFIG_ARCH_EFM32)		+= clk-efm32gg.o
 obj-$(CONFIG_ARCH_HIGHBANK)		+= clk-highbank.o

drivers/clk/clk-axm5516.c

+/*
+ * drivers/clk/clk-axm5516.c
+ *
+ * Provides clock implementations for three different types of clock devices on
+ * the Axxia device: PLL clock, a clock divider and a clock mux.
+ *
+ * Copyright (C) 2014 LSI Corporation
+ *
+ * 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.
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/clk-provider.h>
+#include <linux/regmap.h>
+#include <dt-bindings/clock/lsi,axm5516-clks.h>
+
+
+/**
+ * struct axxia_clk - Common struct to all Axxia clocks.
+ * @hw: clk_hw for the common clk framework
+ * @regmap: Regmap for the clock control registers
+ */
+struct axxia_clk {
+	struct clk_hw hw;
+	struct regmap *regmap;
+};
+#define to_axxia_clk(_hw) container_of(_hw, struct axxia_clk, hw)
+
+/**
+ * struct axxia_pllclk - Axxia PLL generated clock.
+ * @aclk: Common struct
+ * @reg: Offset into regmap for PLL control register
+ */
+struct axxia_pllclk {
+	struct axxia_clk aclk;
+	u32 reg;
+};
+#define to_axxia_pllclk(_aclk) container_of(_aclk, struct axxia_pllclk, aclk)
+
+/**
+ * axxia_pllclk_recalc - Calculate the PLL generated clock rate given the
+ * parent clock rate.
+ */
+static unsigned long
+axxia_pllclk_recalc(struct clk_hw *hw, unsigned long parent_rate)
+{
+	struct axxia_clk *aclk = to_axxia_clk(hw);
+	struct axxia_pllclk *pll = to_axxia_pllclk(aclk);
+	unsigned long rate, fbdiv, refdiv, postdiv;
+	u32 control;
+
+	regmap_read(aclk->regmap, pll->reg, &control);
+	postdiv = ((control >> 0) & 0xf) + 1;
+	fbdiv   = ((control >> 4) & 0xfff) + 3;
+	refdiv  = ((control >> 16) & 0x1f) + 1;
+	rate = (parent_rate / (refdiv * postdiv)) * fbdiv;
+
+	return rate;
+}
+
+static const struct clk_ops axxia_pllclk_ops = {
+	.recalc_rate = axxia_pllclk_recalc,
+};
+
+/**
+ * struct axxia_divclk - Axxia clock divider
+ * @aclk: Common struct
+ * @reg: Offset into regmap for PLL control register
+ * @shift: Bit position for divider value
+ * @width: Number of bits in divider value
+ */
+struct axxia_divclk {
+	struct axxia_clk aclk;
+	u32 reg;
+	u32 shift;
+	u32 width;
+};
+#define to_axxia_divclk(_aclk) container_of(_aclk, struct axxia_divclk, aclk)
+
+/**
+ * axxia_divclk_recalc_rate - Calculate clock divider output rage
+ */
+static unsigned long
+axxia_divclk_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+	struct axxia_clk *aclk = to_axxia_clk(hw);
+	struct axxia_divclk *divclk = to_axxia_divclk(aclk);
+	u32 ctrl, div;
+
+	regmap_read(aclk->regmap, divclk->reg, &ctrl);
+	div = 1 + ((ctrl >> divclk->shift) & ((1 << divclk->width)-1));
+
+	return parent_rate / div;
+}
+
+static const struct clk_ops axxia_divclk_ops = {
+	.recalc_rate = axxia_divclk_recalc_rate,
+};
+
+/**
+ * struct axxia_clkmux - Axxia clock mux
+ * @aclk: Common struct
+ * @reg: Offset into regmap for PLL control register
+ * @shift: Bit position for selection value
+ * @width: Number of bits in selection value
+ */
+struct axxia_clkmux {
+	struct axxia_clk aclk;
+	u32 reg;
+	u32 shift;
+	u32 width;
+};
+#define to_axxia_clkmux(_aclk) container_of(_aclk, struct axxia_clkmux, aclk)
+
+/**
+ * axxia_clkmux_get_parent - Return the index of selected parent clock
+ */
+static u8 axxia_clkmux_get_parent(struct clk_hw *hw)
+{
+	struct axxia_clk *aclk = to_axxia_clk(hw);
+	struct axxia_clkmux *mux = to_axxia_clkmux(aclk);
+	u32 ctrl, parent;
+
+	regmap_read(aclk->regmap, mux->reg, &ctrl);
+	parent = (ctrl >> mux->shift) & ((1 << mux->width) - 1);
+
+	return (u8) parent;
+}
+
+static const struct clk_ops axxia_clkmux_ops = {
+	.get_parent = axxia_clkmux_get_parent,
+};
+
+
+/*
+ * PLLs
+ */
+
+static struct axxia_pllclk clk_fab_pll = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_fab_pll",
+		.parent_names = (const char *[]){
+			"clk_ref0"
+		},
+		.num_parents = 1,
+		.ops = &axxia_pllclk_ops,
+	},
+	.reg   = 0x01800,
+};
+
+static struct axxia_pllclk clk_cpu_pll = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_cpu_pll",
+		.parent_names = (const char *[]){
+			"clk_ref0"
+		},
+		.num_parents = 1,
+		.ops = &axxia_pllclk_ops,
+	},
+	.reg   = 0x02000,
+};
+
+static struct axxia_pllclk clk_sys_pll = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_sys_pll",
+		.parent_names = (const char *[]){
+			"clk_ref0"
+		},
+		.num_parents = 1,
+		.ops = &axxia_pllclk_ops,
+	},
+	.reg   = 0x02800,
+};
+
+static struct axxia_pllclk clk_sm0_pll = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_sm0_pll",
+		.parent_names = (const char *[]){
+			"clk_ref2"
+		},
+		.num_parents = 1,
+		.ops = &axxia_pllclk_ops,
+	},
+	.reg   = 0x03000,
+};
+
+static struct axxia_pllclk clk_sm1_pll = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_sm1_pll",
+		.parent_names = (const char *[]){
+			"clk_ref1"
+		},
+		.num_parents = 1,
+		.ops = &axxia_pllclk_ops,
+	},
+	.reg   = 0x03800,
+};
+
+/*
+ * Clock dividers
+ */
+
+static struct axxia_divclk clk_cpu0_div = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_cpu0_div",
+		.parent_names = (const char *[]){
+			"clk_cpu_pll"
+		},
+		.num_parents = 1,
+		.ops = &axxia_divclk_ops,
+	},
+	.reg   = 0x10008,
+	.shift = 0,
+	.width = 4,
+};
+
+static struct axxia_divclk clk_cpu1_div = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_cpu1_div",
+		.parent_names = (const char *[]){
+			"clk_cpu_pll"
+		},
+		.num_parents = 1,
+		.ops = &axxia_divclk_ops,
+	},
+	.reg   = 0x10008,
+	.shift = 4,
+	.width = 4,
+};
+
+static struct axxia_divclk clk_cpu2_div = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_cpu2_div",
+		.parent_names = (const char *[]){
+			"clk_cpu_pll"
+		},
+		.num_parents = 1,
+		.ops = &axxia_divclk_ops,
+	},
+	.reg   = 0x10008,
+	.shift = 8,
+	.width = 4,
+};
+
+static struct axxia_divclk clk_cpu3_div = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_cpu3_div",
+		.parent_names = (const char *[]){
+			"clk_cpu_pll"
+		},
+		.num_parents = 1,
+		.ops = &axxia_divclk_ops,
+	},
+	.reg   = 0x10008,
+	.shift = 12,
+	.width = 4,
+};
+
+static struct axxia_divclk clk_nrcp_div = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_nrcp_div",
+		.parent_names = (const char *[]){
+			"clk_sys_pll"
+		},
+		.num_parents = 1,
+		.ops = &axxia_divclk_ops,
+	},
+	.reg   = 0x1000c,
+	.shift = 0,
+	.width = 4,
+};
+
+static struct axxia_divclk clk_sys_div = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_sys_div",
+		.parent_names = (const char *[]){
+			"clk_sys_pll"
+		},
+		.num_parents = 1,
+		.ops = &axxia_divclk_ops,
+	},
+	.reg   = 0x1000c,
+	.shift = 4,
+	.width = 4,
+};
+
+static struct axxia_divclk clk_fab_div = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_fab_div",
+		.parent_names = (const char *[]){
+			"clk_fab_pll"
+		},
+		.num_parents = 1,
+		.ops = &axxia_divclk_ops,
+	},
+	.reg   = 0x1000c,
+	.shift = 8,
+	.width = 4,
+};
+
+static struct axxia_divclk clk_per_div = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_per_div",
+		.parent_names = (const char *[]){
+			"clk_sm1_pll"
+		},
+		.num_parents = 1,
+		.flags = CLK_IS_BASIC,
+		.ops = &axxia_divclk_ops,
+	},
+	.reg   = 0x1000c,
+	.shift = 12,
+	.width = 4,
+};
+
+static struct axxia_divclk clk_mmc_div = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_mmc_div",
+		.parent_names = (const char *[]){
+			"clk_sm1_pll"
+		},
+		.num_parents = 1,
+		.flags = CLK_IS_BASIC,
+		.ops = &axxia_divclk_ops,
+	},
+	.reg   = 0x1000c,
+	.shift = 16,
+	.width = 4,
+};
+
+/*
+ * Clock MUXes
+ */
+
+static struct axxia_clkmux clk_cpu0_mux = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_cpu0",
+		.parent_names = (const char *[]){
+			"clk_ref0",
+			"clk_cpu_pll",
+			"clk_cpu0_div",
+			"clk_cpu0_div"
+		},
+		.num_parents = 4,
+		.ops = &axxia_clkmux_ops,
+	},
+	.reg   = 0x10000,
+	.shift = 0,
+	.width = 2,
+};
+
+static struct axxia_clkmux clk_cpu1_mux = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_cpu1",
+		.parent_names = (const char *[]){
+			"clk_ref0",
+			"clk_cpu_pll",
+			"clk_cpu1_div",
+			"clk_cpu1_div"
+		},
+		.num_parents = 4,
+		.ops = &axxia_clkmux_ops,
+	},
+	.reg   = 0x10000,
+	.shift = 2,
+	.width = 2,
+};
+
+static struct axxia_clkmux clk_cpu2_mux = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_cpu2",
+		.parent_names = (const char *[]){
+			"clk_ref0",
+			"clk_cpu_pll",
+			"clk_cpu2_div",
+			"clk_cpu2_div"
+		},
+		.num_parents = 4,
+		.ops = &axxia_clkmux_ops,
+	},
+	.reg   = 0x10000,
+	.shift = 4,
+	.width = 2,
+};
+
+static struct axxia_clkmux clk_cpu3_mux = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_cpu3",
+		.parent_names = (const char *[]){
+			"clk_ref0",
+			"clk_cpu_pll",
+			"clk_cpu3_div",
+			"clk_cpu3_div"
+		},
+		.num_parents = 4,
+		.ops = &axxia_clkmux_ops,
+	},
+	.reg   = 0x10000,
+	.shift = 6,
+	.width = 2,
+};
+
+static struct axxia_clkmux clk_nrcp_mux = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_nrcp",
+		.parent_names = (const char *[]){
+			"clk_ref0",
+			"clk_sys_pll",
+			"clk_nrcp_div",
+			"clk_nrcp_div"
+		},
+		.num_parents = 4,
+		.ops = &axxia_clkmux_ops,
+	},
+	.reg   = 0x10004,
+	.shift = 0,
+	.width = 2,
+};
+
+static struct axxia_clkmux clk_sys_mux = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_sys",
+		.parent_names = (const char *[]){
+			"clk_ref0",
+			"clk_sys_pll",
+			"clk_sys_div",
+			"clk_sys_div"
+		},
+		.num_parents = 4,
+		.ops = &axxia_clkmux_ops,
+	},
+	.reg   = 0x10004,
+	.shift = 2,
+	.width = 2,
+};
+
+static struct axxia_clkmux clk_fab_mux = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_fab",
+		.parent_names = (const char *[]){
+			"clk_ref0",
+			"clk_fab_pll",
+			"clk_fab_div",
+			"clk_fab_div"
+		},
+		.num_parents = 4,
+		.ops = &axxia_clkmux_ops,
+	},
+	.reg   = 0x10004,
+	.shift = 4,
+	.width = 2,
+};
+
+static struct axxia_clkmux clk_per_mux = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_per",
+		.parent_names = (const char *[]){
+			"clk_ref1",
+			"clk_per_div"
+		},
+		.num_parents = 2,
+		.ops = &axxia_clkmux_ops,
+	},
+	.reg   = 0x10004,
+	.shift = 6,
+	.width = 1,
+};
+
+static struct axxia_clkmux clk_mmc_mux = {
+	.aclk.hw.init = &(struct clk_init_data){
+		.name = "clk_mmc",
+		.parent_names = (const char *[]){
+			"clk_ref1",
+			"clk_mmc_div"
+		},
+		.num_parents = 2,
+		.ops = &axxia_clkmux_ops,
+	},
+	.reg   = 0x10004,
+	.shift = 9,
+	.width = 1,
+};
+
+/* Table of all supported clocks indexed by the clock identifiers from the
+ * device tree binding
+ */
+static struct axxia_clk *axmclk_clocks[] = {
+	[AXXIA_CLK_FAB_PLL]  = &clk_fab_pll.aclk,
+	[AXXIA_CLK_CPU_PLL]  = &clk_cpu_pll.aclk,
+	[AXXIA_CLK_SYS_PLL]  = &clk_sys_pll.aclk,
+	[AXXIA_CLK_SM0_PLL]  = &clk_sm0_pll.aclk,
+	[AXXIA_CLK_SM1_PLL]  = &clk_sm1_pll.aclk,
+	[AXXIA_CLK_FAB_DIV]  = &clk_fab_div.aclk,
+	[AXXIA_CLK_SYS_DIV]  = &clk_sys_div.aclk,
+	[AXXIA_CLK_NRCP_DIV] = &clk_nrcp_div.aclk,
+	[AXXIA_CLK_CPU0_DIV] = &clk_cpu0_div.aclk,
+	[AXXIA_CLK_CPU1_DIV] = &clk_cpu1_div.aclk,
+	[AXXIA_CLK_CPU2_DIV] = &clk_cpu2_div.aclk,
+	[AXXIA_CLK_CPU3_DIV] = &clk_cpu3_div.aclk,
+	[AXXIA_CLK_PER_DIV]  = &clk_per_div.aclk,
+	[AXXIA_CLK_MMC_DIV]  = &clk_mmc_div.aclk,
+	[AXXIA_CLK_FAB]      = &clk_fab_mux.aclk,
+	[AXXIA_CLK_SYS]      = &clk_sys_mux.aclk,
+	[AXXIA_CLK_NRCP]     = &clk_nrcp_mux.aclk,
+	[AXXIA_CLK_CPU0]     = &clk_cpu0_mux.aclk,
+	[AXXIA_CLK_CPU1]     = &clk_cpu1_mux.aclk,
+	[AXXIA_CLK_CPU2]     = &clk_cpu2_mux.aclk,
+	[AXXIA_CLK_CPU3]     = &clk_cpu3_mux.aclk,
+	[AXXIA_CLK_PER]      = &clk_per_mux.aclk,
+	[AXXIA_CLK_MMC]      = &clk_mmc_mux.aclk,
+};
+
+static const struct regmap_config axmclk_regmap_config = {
+	.reg_bits	= 32,
+	.reg_stride	= 4,
+	.val_bits	= 32,
+	.max_register	= 0x1fffc,
+	.fast_io	= true,
+};
+
+static const struct of_device_id axmclk_match_table[] = {
+	{ .compatible = "lsi,axm5516-clks" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, axmclk_match_table);
+
+struct axmclk_priv {
+	struct clk_onecell_data onecell;
+	struct clk *clks[];
+};
+
+static int axmclk_probe(struct platform_device *pdev)
+{
+	void __iomem *base;
+	struct resource *res;
+	int i, ret;
+	struct device *dev = &pdev->dev;
+	struct clk *clk;
+	struct regmap *regmap;
+	size_t num_clks;
+	struct axmclk_priv *priv;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	regmap = devm_regmap_init_mmio(dev, base, &axmclk_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	num_clks = ARRAY_SIZE(axmclk_clocks);
+	pr_info("axmclk: supporting %u clocks\n", num_clks);
+	priv = devm_kzalloc(dev, sizeof(*priv) + sizeof(*priv->clks) * num_clks,
+			    GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->onecell.clks = priv->clks;
+	priv->onecell.clk_num = num_clks;
+
+	/* Update each entry with the allocated regmap and register the clock
+	 * with the common clock framework
+	 */
+	for (i = 0; i < num_clks; i++) {
+		axmclk_clocks[i]->regmap = regmap;
+		clk = devm_clk_register(dev, &axmclk_clocks[i]->hw);
+		if (IS_ERR(clk))
+			return PTR_ERR(clk);
+		priv->clks[i] = clk;
+	}
+
+	ret = of_clk_add_provider(dev->of_node,
+				  of_clk_src_onecell_get, &priv->onecell);
+
+	return ret;
+}
+
+static int axmclk_remove(struct platform_device *pdev)
+{
+	of_clk_del_provider(pdev->dev.of_node);
+	return 0;
+}
+
+static struct platform_driver axmclk_driver = {
+	.probe		= axmclk_probe,
+	.remove		= axmclk_remove,
+	.driver		= {
+		.name	= "clk-axm5516",
+		.owner	= THIS_MODULE,
+		.of_match_table = axmclk_match_table,
+	},
+};
+
+static int __init axmclk_init(void)
+{
+	return platform_driver_register(&axmclk_driver);
+}
+core_initcall(axmclk_init);
+
+static void __exit axmclk_exit(void)
+{
+	platform_driver_unregister(&axmclk_driver);
+}
+module_exit(axmclk_exit);
+
+MODULE_DESCRIPTION("AXM5516 clock driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:clk-axm5516");