clk: arm: sunxi: Add a new clock driver for sunxi SOCs

This commit implements the base CPU clocks for sunxi devices. It has been tested using a slightly modified cpufreq driver from the linux-sunxi 3.0 tree. Additionally, document the new bindings introduced by this patch. Idling: / # cat /sys/kernel/debug/clk/clk_summary clock enable_cnt prepare_cnt rate --------------------------------------------------------------------- osc32k 0 0 32768 osc24M_fixed 0 0 24000000 osc24M 0 0 24000000 apb1_mux 0 0 24000000 apb1 0 0 24000000 pll1 0 0 60000000 cpu 0 0 60000000 axi 0 0 60000000 ahb 0 0 60000000 apb0 0 0 30000000 dummy 0 0 0 After "yes >/dev/null &": / # cat /sys/kernel/debug/clk/clk_summary clock enable_cnt prepare_cnt rate --------------------------------------------------------------------- osc32k 0 0 32768 osc24M_fixed 0 0 24000000 osc24M 0 0 24000000 apb1_mux 0 0 24000000 apb1 0 0 24000000 pll1 0 0 1008000000 cpu 0 0 1008000000 axi 0 0 336000000 ahb 0 0 168000000 apb0 0 0 84000000 dummy 0 0 0 Signed-off-by: Emilio López <emilio@elopez.com.ar> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Mike Turquette <mturquette@linaro.org>
git-mirror · Mar 27, 2013 · e874a66 · e874a66
1 parent b548916
commit e874a66
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diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt b/Documentation/devicetree/bindings/clock/sunxi.txt
@@ -0,0 +1,44 @@
+Device Tree Clock bindings for arch-sunxi
+
+This binding uses the common clock binding[1].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- compatible : shall be one of the following:
+	"allwinner,sunxi-osc-clk" - for a gatable oscillator
+	"allwinner,sunxi-pll1-clk" - for the main PLL clock
+	"allwinner,sunxi-cpu-clk" - for the CPU multiplexer clock
+	"allwinner,sunxi-axi-clk" - for the sunxi AXI clock
+	"allwinner,sunxi-ahb-clk" - for the sunxi AHB clock
+	"allwinner,sunxi-apb0-clk" - for the sunxi APB0 clock
+	"allwinner,sunxi-apb1-clk" - for the sunxi APB1 clock
+	"allwinner,sunxi-apb1-mux-clk" - for the sunxi APB1 clock muxing
+
+Required properties for all clocks:
+- reg : shall be the control register address for the clock.
+- clocks : shall be the input parent clock(s) phandle for the clock
+- #clock-cells : from common clock binding; shall be set to 0.
+
+For example:
+
+osc24M: osc24M@01c20050 {
+	#clock-cells = <0>;
+	compatible = "allwinner,sunxi-osc-clk";
+	reg = <0x01c20050 0x4>;
+	clocks = <&osc24M_fixed>;
+};
+
+pll1: pll1@01c20000 {
+	#clock-cells = <0>;
+	compatible = "allwinner,sunxi-pll1-clk";
+	reg = <0x01c20000 0x4>;
+	clocks = <&osc24M>;
+};
+
+cpu: cpu@01c20054 {
+	#clock-cells = <0>;
+	compatible = "allwinner,sunxi-cpu-clk";
+	reg = <0x01c20054 0x4>;
+	clocks = <&osc32k>, <&osc24M>, <&pll1>;
+};
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
@@ -24,6 +24,7 @@ ifeq ($(CONFIG_COMMON_CLK), y)
 obj-$(CONFIG_ARCH_MMP)		+= mmp/
 endif
 obj-$(CONFIG_MACH_LOONGSON1)	+= clk-ls1x.o
+obj-$(CONFIG_ARCH_SUNXI)	+= sunxi/
 obj-$(CONFIG_ARCH_U8500)	+= ux500/
 obj-$(CONFIG_ARCH_VT8500)	+= clk-vt8500.o
 obj-$(CONFIG_ARCH_ZYNQ)		+= clk-zynq.o

diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for sunxi specific clk
+#
+
+obj-y += clk-sunxi.o clk-factors.o
diff --git a/drivers/clk/sunxi/clk-factors.c b/drivers/clk/sunxi/clk-factors.c
@@ -0,0 +1,180 @@
+/*
+ * Copyright (C) 2013 Emilio López <emilio@elopez.com.ar>
+ *
+ * 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.
+ *
+ * Adjustable factor-based clock implementation
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/string.h>
+
+#include <linux/delay.h>
+
+#include "clk-factors.h"
+
+/*
+ * DOC: basic adjustable factor-based clock that cannot gate
+ *
+ * Traits of this clock:
+ * prepare - clk_prepare only ensures that parents are prepared
+ * enable - clk_enable only ensures that parents are enabled
+ * rate - rate is adjustable.
+ *        clk->rate = (parent->rate * N * (K + 1) >> P) / (M + 1)
+ * parent - fixed parent.  No clk_set_parent support
+ */
+
+struct clk_factors {
+	struct clk_hw hw;
+	void __iomem *reg;
+	struct clk_factors_config *config;
+	void (*get_factors) (u32 *rate, u32 parent, u8 *n, u8 *k, u8 *m, u8 *p);
+	spinlock_t *lock;
+};
+
+#define to_clk_factors(_hw) container_of(_hw, struct clk_factors, hw)
+
+#define SETMASK(len, pos)		(((-1U) >> (31-len))  << (pos))
+#define CLRMASK(len, pos)		(~(SETMASK(len, pos)))
+#define FACTOR_GET(bit, len, reg)	(((reg) & SETMASK(len, bit)) >> (bit))
+
+#define FACTOR_SET(bit, len, reg, val) \
+	(((reg) & CLRMASK(len, bit)) | (val << (bit)))
+
+static unsigned long clk_factors_recalc_rate(struct clk_hw *hw,
+					     unsigned long parent_rate)
+{
+	u8 n = 1, k = 0, p = 0, m = 0;
+	u32 reg;
+	unsigned long rate;
+	struct clk_factors *factors = to_clk_factors(hw);
+	struct clk_factors_config *config = factors->config;
+
+	/* Fetch the register value */
+	reg = readl(factors->reg);
+
+	/* Get each individual factor if applicable */
+	if (config->nwidth != SUNXI_FACTORS_NOT_APPLICABLE)
+		n = FACTOR_GET(config->nshift, config->nwidth, reg);
+	if (config->kwidth != SUNXI_FACTORS_NOT_APPLICABLE)
+		k = FACTOR_GET(config->kshift, config->kwidth, reg);
+	if (config->mwidth != SUNXI_FACTORS_NOT_APPLICABLE)
+		m = FACTOR_GET(config->mshift, config->mwidth, reg);
+	if (config->pwidth != SUNXI_FACTORS_NOT_APPLICABLE)
+		p = FACTOR_GET(config->pshift, config->pwidth, reg);
+
+	/* Calculate the rate */
+	rate = (parent_rate * n * (k + 1) >> p) / (m + 1);
+
+	return rate;
+}
+
+static long clk_factors_round_rate(struct clk_hw *hw, unsigned long rate,
+				   unsigned long *parent_rate)
+{
+	struct clk_factors *factors = to_clk_factors(hw);
+	factors->get_factors((u32 *)&rate, (u32)*parent_rate,
+			     NULL, NULL, NULL, NULL);
+
+	return rate;
+}
+
+static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long parent_rate)
+{
+	u8 n, k, m, p;
+	u32 reg;
+	struct clk_factors *factors = to_clk_factors(hw);
+	struct clk_factors_config *config = factors->config;
+	unsigned long flags = 0;
+
+	factors->get_factors((u32 *)&rate, (u32)parent_rate, &n, &k, &m, &p);
+
+	if (factors->lock)
+		spin_lock_irqsave(factors->lock, flags);
+
+	/* Fetch the register value */
+	reg = readl(factors->reg);
+
+	/* Set up the new factors - macros do not do anything if width is 0 */
+	reg = FACTOR_SET(config->nshift, config->nwidth, reg, n);
+	reg = FACTOR_SET(config->kshift, config->kwidth, reg, k);
+	reg = FACTOR_SET(config->mshift, config->mwidth, reg, m);
+	reg = FACTOR_SET(config->pshift, config->pwidth, reg, p);
+
+	/* Apply them now */
+	writel(reg, factors->reg);
+
+	/* delay 500us so pll stabilizes */
+	__delay((rate >> 20) * 500 / 2);
+
+	if (factors->lock)
+		spin_unlock_irqrestore(factors->lock, flags);
+
+	return 0;
+}
+
+static const struct clk_ops clk_factors_ops = {
+	.recalc_rate = clk_factors_recalc_rate,
+	.round_rate = clk_factors_round_rate,
+	.set_rate = clk_factors_set_rate,
+};
+
+/**
+ * clk_register_factors - register a factors clock with
+ * the clock framework
+ * @dev: device registering this clock
+ * @name: name of this clock
+ * @parent_name: name of clock's parent
+ * @flags: framework-specific flags
+ * @reg: register address to adjust factors
+ * @config: shift and width of factors n, k, m and p
+ * @get_factors: function to calculate the factors for a given frequency
+ * @lock: shared register lock for this clock
+ */
+struct clk *clk_register_factors(struct device *dev, const char *name,
+				 const char *parent_name,
+				 unsigned long flags, void __iomem *reg,
+				 struct clk_factors_config *config,
+				 void (*get_factors)(u32 *rate, u32 parent,
+						     u8 *n, u8 *k, u8 *m, u8 *p),
+				 spinlock_t *lock)
+{
+	struct clk_factors *factors;
+	struct clk *clk;
+	struct clk_init_data init;
+
+	/* allocate the factors */
+	factors = kzalloc(sizeof(struct clk_factors), GFP_KERNEL);
+	if (!factors) {
+		pr_err("%s: could not allocate factors clk\n", __func__);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	init.name = name;
+	init.ops = &clk_factors_ops;
+	init.flags = flags;
+	init.parent_names = (parent_name ? &parent_name : NULL);
+	init.num_parents = (parent_name ? 1 : 0);
+
+	/* struct clk_factors assignments */
+	factors->reg = reg;
+	factors->config = config;
+	factors->lock = lock;
+	factors->hw.init = &init;
+	factors->get_factors = get_factors;
+
+	/* register the clock */
+	clk = clk_register(dev, &factors->hw);
+
+	if (IS_ERR(clk))
+		kfree(factors);
+
+	return clk;
+}
diff --git a/drivers/clk/sunxi/clk-factors.h b/drivers/clk/sunxi/clk-factors.h
@@ -0,0 +1,27 @@
+#ifndef __MACH_SUNXI_CLK_FACTORS_H
+#define __MACH_SUNXI_CLK_FACTORS_H
+
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
+
+#define SUNXI_FACTORS_NOT_APPLICABLE	(0)
+
+struct clk_factors_config {
+	u8 nshift;
+	u8 nwidth;
+	u8 kshift;
+	u8 kwidth;
+	u8 mshift;
+	u8 mwidth;
+	u8 pshift;
+	u8 pwidth;
+};
+
+struct clk *clk_register_factors(struct device *dev, const char *name,
+				 const char *parent_name,
+				 unsigned long flags, void __iomem *reg,
+				 struct clk_factors_config *config,
+				 void (*get_factors) (u32 *rate, u32 parent_rate,
+						      u8 *n, u8 *k, u8 *m, u8 *p),
+				 spinlock_t *lock);
+#endif