clk: Add support for fundamental zynq clks

Provide simplified models for the necessary clocks on the zynq-7000
platform.  Currently, the PLLs, the CPU clock network, and the basic
peripheral clock networks (for SDIO, SMC, SPI, QSPI, UART) are modelled.

OF bindings are also provided and documented.
Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Acked-by: Mike Turquette <mturquette@linaro.org>
Acked-by: Michal Simek <michal.simek@xilinx.com>

Documentation/devicetree/bindings/clock/zynq-7000.txt

+Device Tree Clock bindings for the Zynq 7000 EPP
+
+The Zynq EPP has several different clk providers, each with there own bindings.
+The purpose of this document is to document their usage.
+
+See clock_bindings.txt for more information on the generic clock bindings.
+See Chapter 25 of Zynq TRM for more information about Zynq clocks.
+
+== PLLs ==
+
+Used to describe the ARM_PLL, DDR_PLL, and IO_PLL.
+
+Required properties:
+- #clock-cells : shall be 0 (only one clock is output from this node)
+- compatible : "xlnx,zynq-pll"
+- reg : pair of u32 values, which are the address offsets within the SLCR
+        of the relevant PLL_CTRL register and PLL_CFG register respectively
+- clocks : phandle for parent clock.  should be the phandle for ps_clk
+
+Optional properties:
+- clock-output-names : name of the output clock
+
+Example:
+	armpll: armpll {
+		#clock-cells = <0>;
+		compatible = "xlnx,zynq-pll";
+		clocks = <&ps_clk>;
+		reg = <0x100 0x110>;
+		clock-output-names = "armpll";
+	};
+
+== Peripheral clocks ==
+
+Describes clock node for the SDIO, SMC, SPI, QSPI, and UART clocks.
+
+Required properties:
+- #clock-cells : shall be 1
+- compatible : "xlnx,zynq-periph-clock"
+- reg : a single u32 value, describing the offset within the SLCR where
+        the CLK_CTRL register is found for this peripheral
+- clocks : phandle for parent clocks.  should hold phandles for
+           the IO_PLL, ARM_PLL, and DDR_PLL in order
+- clock-output-names : names of the output clock(s).  For peripherals that have
+                       two output clocks (for example, the UART), two clocks
+                       should be listed.
+
+Example:
+	uart_clk: uart_clk {
+		#clock-cells = <1>;
+		compatible = "xlnx,zynq-periph-clock";
+		clocks = <&iopll &armpll &ddrpll>;
+		reg = <0x154>;
+		clock-output-names = "uart0_ref_clk",
+				     "uart1_ref_clk";
+	};

drivers/clk/clk-zynq.c

+/*
+ * Copyright (c) 2012 National Instruments
+ *
+ * Josh Cartwright <josh.cartwright@ni.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/clk-provider.h>
+
+static void __iomem *slcr_base;
+
+struct zynq_pll_clk {
+	struct clk_hw	hw;
+	void __iomem	*pll_ctrl;
+	void __iomem	*pll_cfg;
+};
+
+#define to_zynq_pll_clk(hw)	container_of(hw, struct zynq_pll_clk, hw)
+
+#define CTRL_PLL_FDIV(x)	((x) >> 12)
+
+static unsigned long zynq_pll_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	struct zynq_pll_clk *pll = to_zynq_pll_clk(hw);
+	return parent_rate * CTRL_PLL_FDIV(ioread32(pll->pll_ctrl));
+}
+
+static const struct clk_ops zynq_pll_clk_ops = {
+	.recalc_rate	= zynq_pll_recalc_rate,
+};
+
+static void __init zynq_pll_clk_setup(struct device_node *np)
+{
+	struct clk_init_data init;
+	struct zynq_pll_clk *pll;
+	const char *parent_name;
+	struct clk *clk;
+	u32 regs[2];
+	int ret;
+
+	ret = of_property_read_u32_array(np, "reg", regs, ARRAY_SIZE(regs));
+	if (WARN_ON(ret))
+		return;
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (WARN_ON(!pll))
+		return;
+
+	pll->pll_ctrl = slcr_base + regs[0];
+	pll->pll_cfg  = slcr_base + regs[1];
+
+	of_property_read_string(np, "clock-output-names", &init.name);
+
+	init.ops = &zynq_pll_clk_ops;
+	parent_name = of_clk_get_parent_name(np, 0);
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	pll->hw.init = &init;
+
+	clk = clk_register(NULL, &pll->hw);
+	if (WARN_ON(IS_ERR(clk)))
+		return;
+
+	ret = of_clk_add_provider(np, of_clk_src_simple_get, clk);
+	if (WARN_ON(ret))
+		return;
+}
+
+struct zynq_periph_clk {
+	struct clk_hw		hw;
+	struct clk_onecell_data	onecell_data;
+	struct clk		*gates[2];
+	void __iomem		*clk_ctrl;
+	spinlock_t		clkact_lock;
+};
+
+#define to_zynq_periph_clk(hw)	container_of(hw, struct zynq_periph_clk, hw)
+
+static const u8 periph_clk_parent_map[] = {
+	0, 0, 1, 2
+};
+#define PERIPH_CLK_CTRL_SRC(x)	(periph_clk_parent_map[((x) & 0x30) >> 4])
+#define PERIPH_CLK_CTRL_DIV(x)	(((x) & 0x3F00) >> 8)
+
+static unsigned long zynq_periph_recalc_rate(struct clk_hw *hw,
+					     unsigned long parent_rate)
+{
+	struct zynq_periph_clk *periph = to_zynq_periph_clk(hw);
+	return parent_rate / PERIPH_CLK_CTRL_DIV(ioread32(periph->clk_ctrl));
+}
+
+static u8 zynq_periph_get_parent(struct clk_hw *hw)
+{
+	struct zynq_periph_clk *periph = to_zynq_periph_clk(hw);
+	return PERIPH_CLK_CTRL_SRC(ioread32(periph->clk_ctrl));
+}
+
+static const struct clk_ops zynq_periph_clk_ops = {
+	.recalc_rate	= zynq_periph_recalc_rate,
+	.get_parent	= zynq_periph_get_parent,
+};
+
+static void __init zynq_periph_clk_setup(struct device_node *np)
+{
+	struct zynq_periph_clk *periph;
+	const char *parent_names[3];
+	struct clk_init_data init;
+	int clk_num = 0, err;
+	const char *name;
+	struct clk *clk;
+	u32 reg;
+	int i;
+
+	err = of_property_read_u32(np, "reg", &reg);
+	if (WARN_ON(err))
+		return;
+
+	periph = kzalloc(sizeof(*periph), GFP_KERNEL);
+	if (WARN_ON(!periph))
+		return;
+
+	periph->clk_ctrl = slcr_base + reg;
+	spin_lock_init(&periph->clkact_lock);
+
+	init.name = np->name;
+	init.ops = &zynq_periph_clk_ops;
+	for (i = 0; i < ARRAY_SIZE(parent_names); i++)
+		parent_names[i] = of_clk_get_parent_name(np, i);
+	init.parent_names = parent_names;
+	init.num_parents = ARRAY_SIZE(parent_names);
+
+	periph->hw.init = &init;
+
+	clk = clk_register(NULL, &periph->hw);
+	if (WARN_ON(IS_ERR(clk)))
+		return;
+
+	err = of_clk_add_provider(np, of_clk_src_simple_get, clk);
+	if (WARN_ON(err))
+		return;
+
+	err = of_property_read_string_index(np, "clock-output-names", 0,
+					    &name);
+	if (WARN_ON(err))
+		return;
+
+	periph->gates[0] = clk_register_gate(NULL, name, np->name, 0,
+					     periph->clk_ctrl, 0, 0,
+					     &periph->clkact_lock);
+	if (WARN_ON(IS_ERR(periph->gates[0])))
+		return;
+	clk_num++;
+
+	/* some periph clks have 2 downstream gates */
+	err = of_property_read_string_index(np, "clock-output-names", 1,
+					    &name);
+	if (err != -ENODATA) {
+		periph->gates[1] = clk_register_gate(NULL, name, np->name, 0,
+						     periph->clk_ctrl, 1, 0,
+						     &periph->clkact_lock);
+		if (WARN_ON(IS_ERR(periph->gates[1])))
+			return;
+		clk_num++;
+	}
+
+	periph->onecell_data.clks = periph->gates;
+	periph->onecell_data.clk_num = clk_num;
+
+	err = of_clk_add_provider(np, of_clk_src_onecell_get,
+				  &periph->onecell_data);
+	if (WARN_ON(err))
+		return;
+}
+
+/* CPU Clock domain is modelled as a mux with 4 children subclks, whose
+ * derivative rates depend on CLK_621_TRUE
+ */
+
+struct zynq_cpu_clk {
+	struct clk_hw		hw;
+	struct clk_onecell_data	onecell_data;
+	struct clk		*subclks[4];
+	void __iomem		*clk_ctrl;
+	spinlock_t		clkact_lock;
+};
+
+#define to_zynq_cpu_clk(hw)	container_of(hw, struct zynq_cpu_clk, hw)
+
+static const u8 zynq_cpu_clk_parent_map[] = {
+	1, 1, 2, 0
+};
+#define CPU_CLK_SRCSEL(x)	(zynq_cpu_clk_parent_map[(((x) & 0x30) >> 4)])
+#define CPU_CLK_CTRL_DIV(x)	(((x) & 0x3F00) >> 8)
+
+static u8 zynq_cpu_clk_get_parent(struct clk_hw *hw)
+{
+	struct zynq_cpu_clk *cpuclk = to_zynq_cpu_clk(hw);
+	return CPU_CLK_SRCSEL(ioread32(cpuclk->clk_ctrl));
+}
+
+static unsigned long zynq_cpu_clk_recalc_rate(struct clk_hw *hw,
+					      unsigned long parent_rate)
+{
+	struct zynq_cpu_clk *cpuclk = to_zynq_cpu_clk(hw);
+	return parent_rate / CPU_CLK_CTRL_DIV(ioread32(cpuclk->clk_ctrl));
+}
+
+static const struct clk_ops zynq_cpu_clk_ops = {
+	.get_parent	= zynq_cpu_clk_get_parent,
+	.recalc_rate	= zynq_cpu_clk_recalc_rate,
+};
+
+struct zynq_cpu_subclk {
+	struct clk_hw	hw;
+	void __iomem	*clk_621;
+	enum {
+		CPU_SUBCLK_6X4X,
+		CPU_SUBCLK_3X2X,
+		CPU_SUBCLK_2X,
+		CPU_SUBCLK_1X,
+	} which;
+};
+
+#define CLK_621_TRUE(x)	((x) & 1)
+
+#define to_zynq_cpu_subclk(hw)	container_of(hw, struct zynq_cpu_subclk, hw);
+
+static unsigned long zynq_cpu_subclk_recalc_rate(struct clk_hw *hw,
+						 unsigned long parent_rate)
+{
+	unsigned long uninitialized_var(rate);
+	struct zynq_cpu_subclk *subclk;
+	bool is_621;
+
+	subclk = to_zynq_cpu_subclk(hw)
+	is_621 = CLK_621_TRUE(ioread32(subclk->clk_621));
+
+	switch (subclk->which) {
+	case CPU_SUBCLK_6X4X:
+		rate = parent_rate;
+		break;
+	case CPU_SUBCLK_3X2X:
+		rate = parent_rate / 2;
+		break;
+	case CPU_SUBCLK_2X:
+		rate = parent_rate / (is_621 ? 3 : 2);
+		break;
+	case CPU_SUBCLK_1X:
+		rate = parent_rate / (is_621 ? 6 : 4);
+		break;
+	};
+
+	return rate;
+}
+
+static const struct clk_ops zynq_cpu_subclk_ops = {
+	.recalc_rate	= zynq_cpu_subclk_recalc_rate,
+};
+
+static struct clk *zynq_cpu_subclk_setup(struct device_node *np, u8 which,
+					 void __iomem *clk_621)
+{
+	struct zynq_cpu_subclk *subclk;
+	struct clk_init_data init;
+	struct clk *clk;
+	int err;
+
+	err = of_property_read_string_index(np, "clock-output-names",
+					    which, &init.name);
+	if (WARN_ON(err))
+		goto err_read_output_name;
+
+	subclk = kzalloc(sizeof(*subclk), GFP_KERNEL);
+	if (!subclk)
+		goto err_subclk_alloc;
+
+	subclk->clk_621 = clk_621;
+	subclk->which = which;
+
+	init.ops = &zynq_cpu_subclk_ops;
+	init.parent_names = &np->name;
+	init.num_parents = 1;
+
+	subclk->hw.init = &init;
+
+	clk = clk_register(NULL, &subclk->hw);
+	if (WARN_ON(IS_ERR(clk)))
+		goto err_clk_register;
+
+	return clk;
+
+err_clk_register:
+	kfree(subclk);
+err_subclk_alloc:
+err_read_output_name:
+	return ERR_PTR(-EINVAL);
+}
+
+static void __init zynq_cpu_clk_setup(struct device_node *np)
+{
+	struct zynq_cpu_clk *cpuclk;
+	const char *parent_names[3];
+	struct clk_init_data init;
+	void __iomem *clk_621;
+	struct clk *clk;
+	u32 reg[2];
+	int err;
+	int i;
+
+	err = of_property_read_u32_array(np, "reg", reg, ARRAY_SIZE(reg));
+	if (WARN_ON(err))
+		return;
+
+	cpuclk = kzalloc(sizeof(*cpuclk), GFP_KERNEL);
+	if (WARN_ON(!cpuclk))
+		return;
+
+	cpuclk->clk_ctrl = slcr_base + reg[0];
+	clk_621 = slcr_base + reg[1];
+	spin_lock_init(&cpuclk->clkact_lock);
+
+	init.name = np->name;
+	init.ops = &zynq_cpu_clk_ops;
+	for (i = 0; i < ARRAY_SIZE(parent_names); i++)
+		parent_names[i] = of_clk_get_parent_name(np, i);
+	init.parent_names = parent_names;
+	init.num_parents = ARRAY_SIZE(parent_names);
+
+	cpuclk->hw.init = &init;
+
+	clk = clk_register(NULL, &cpuclk->hw);
+	if (WARN_ON(IS_ERR(clk)))
+		return;
+
+	err = of_clk_add_provider(np, of_clk_src_simple_get, clk);
+	if (WARN_ON(err))
+		return;
+
+	for (i = 0; i < 4; i++) {
+		cpuclk->subclks[i] = zynq_cpu_subclk_setup(np, i, clk_621);
+		if (WARN_ON(IS_ERR(cpuclk->subclks[i])))
+			return;
+	}
+
+	cpuclk->onecell_data.clks = cpuclk->subclks;
+	cpuclk->onecell_data.clk_num = i;
+
+	err = of_clk_add_provider(np, of_clk_src_onecell_get,
+				  &cpuclk->onecell_data);
+	if (WARN_ON(err))
+		return;
+}
+
+static const __initconst struct of_device_id zynq_clk_match[] = {
+	{ .compatible = "fixed-clock", .data = of_fixed_clk_setup, },
+	{ .compatible = "xlnx,zynq-pll", .data = zynq_pll_clk_setup, },
+	{ .compatible = "xlnx,zynq-periph-clock",
+		.data = zynq_periph_clk_setup, },
+	{ .compatible = "xlnx,zynq-cpu-clock", .data = zynq_cpu_clk_setup, },
+	{}
+};
+
+void __init xilinx_zynq_clocks_init(void __iomem *slcr)
+{
+	slcr_base = slcr;
+	of_clk_init(zynq_clk_match);
+}

include/linux/clk/zynq.h

+/*
+ * Copyright (C) 2012 National Instruments
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef __LINUX_CLK_ZYNQ_H_
+#define __LINUX_CLK_ZYNQ_H_
+
+void __init xilinx_zynq_clocks_init(void __iomem *slcr);
+
+#endif