clk: keystone: add Keystone PLL clock driver

Add the driver for the PLL IPs found on Keystone 2 devices. The PLL
IP typically has a multiplier, a divider and a post-divider. The PLL IPs like
ARMPLL, DDRPLL and PAPLL are controlled by the memory mapped register where
as the Main PLL is controlled by a PLL controller and memory map registers.

Signed-off-by: Santosh Shilimkar <[e-mail]>
Signed-off-by: Mike Turquette <[e-mail]>

Documentation/devicetree/bindings/clock/keystone-pll.txt

···
+Status: Unstable - ABI compatibility may be broken in the future
+
+Binding for keystone PLLs. The main PLL IP typically has a multiplier,
+a divider and a post divider. The additional PLL IPs like ARMPLL, DDRPLL
+and PAPLL are controlled by the memory mapped register where as the Main
+PLL is controlled by a PLL controller registers along with memory mapped
+registers.
+
+This binding uses the common clock binding[1].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- #clock-cells : from common clock binding; shall be set to 0.
+- compatible : shall be "ti,keystone,main-pll-clock" or "ti,keystone,pll-clock"
+- clocks : parent clock phandle
+- reg - pll control0 and pll multipler registers
+- reg-names : control and multiplier. The multiplier is applicable only for
+		main pll clock
+- fixed-postdiv : fixed post divider value
+
+Example:
+	mainpllclk: mainpllclk@2310110 {
+		#clock-cells = <0>;
+		compatible = "ti,keystone,main-pll-clock";
+		clocks = <&refclkmain>;
+		reg = <0x02620350 4>, <0x02310110 4>;
+		reg-names = "control", "multiplier";
+		fixed-postdiv = <2>;
+	};
+
+	papllclk: papllclk@2620358 {
+		#clock-cells = <0>;
+		compatible = "ti,keystone,pll-clock";
+		clocks = <&refclkmain>;
+		clock-output-names = "pa-pll-clk";
+		reg = <0x02620358 4>;
+		reg-names = "control";
+		fixed-postdiv = <6>;
+	};
+
+Required properties:
+- #clock-cells : from common clock binding; shall be set to 0.
+- compatible : shall be "ti,keystone,pll-mux-clock"
+- clocks : link phandles of parent clocks
+- reg - pll mux register
+- bit-shift : number of bits to shift the bit-mask
+- bit-mask : arbitrary bitmask for programming the mux
+
+Optional properties:
+- clock-output-names : From common clock binding.
+
+Example:
+	mainmuxclk: mainmuxclk@2310108 {
+		#clock-cells = <0>;
+		compatible = "ti,keystone,pll-mux-clock";
+		clocks = <&mainpllclk>, <&refclkmain>;
+		reg = <0x02310108 4>;
+		bit-shift = <23>;
+		bit-mask = <1>;
+		clock-output-names = "mainmuxclk";
+	};
+
+Required properties:
+- #clock-cells : from common clock binding; shall be set to 0.
+- compatible : shall be "ti,keystone,pll-divider-clock"
+- clocks : parent clock phandle
+- reg - pll mux register
+- bit-shift : number of bits to shift the bit-mask
+- bit-mask : arbitrary bitmask for programming the divider
+
+Optional properties:
+- clock-output-names : From common clock binding.
+
+Example:
+	gemtraceclk: gemtraceclk@2310120 {
+		#clock-cells = <0>;
+		compatible = "ti,keystone,pll-divider-clock";
+		clocks = <&mainmuxclk>;
+		reg = <0x02310120 4>;
+		bit-shift = <0>;
+		bit-mask = <8>;
+		clock-output-names = "gemtraceclk";
+	};

drivers/clk/keystone/pll.c

···
+/*
+ * PLL clock driver for Keystone devices
+ *
+ * Copyright (C) 2013 Texas Instruments Inc.
+ *	Murali Karicheri <[e-mail]>
+ *	Santosh Shilimkar <[e-mail]>
+ *
+ * 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.
+ */
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/of_address.h>
+#include <linux/of.h>
+#include <linux/module.h>
+
+#define PLLM_LOW_MASK		0x3f
+#define PLLM_HIGH_MASK		0x7ffc0
+#define MAIN_PLLM_HIGH_MASK	0x7f000
+#define PLLM_HIGH_SHIFT		6
+#define PLLD_MASK		0x3f
+
+/**
+ * struct clk_pll_data - pll data structure
+ * @has_pllctrl: If set to non zero, lower 6 bits of multiplier is in pllm
+ *	register of pll controller, else it is in the pll_ctrl0((bit 11-6)
+ * @phy_pllm: Physical address of PLLM in pll controller. Used when
+ *	has_pllctrl is non zero.
+ * @phy_pll_ctl0: Physical address of PLL ctrl0. This could be that of
+ *	Main PLL or any other PLLs in the device such as ARM PLL, DDR PLL
+ *	or PA PLL available on keystone2. These PLLs are controlled by
+ *	this register. Main PLL is controlled by a PLL controller.
+ * @pllm: PLL register map address
+ * @pll_ctl0: PLL controller map address
+ * @pllm_lower_mask: multiplier lower mask
+ * @pllm_upper_mask: multiplier upper mask
+ * @pllm_upper_shift: multiplier upper shift
+ * @plld_mask: divider mask
+ * @postdiv: Post divider
+ */
+struct clk_pll_data {
+	bool has_pllctrl;
+	u32 phy_pllm;
+	u32 phy_pll_ctl0;
+	void __iomem *pllm;
+	void __iomem *pll_ctl0;
+	u32 pllm_lower_mask;
+	u32 pllm_upper_mask;
+	u32 pllm_upper_shift;
+	u32 plld_mask;
+	u32 postdiv;
+};
+
+/**
+ * struct clk_pll - Main pll clock
+ * @hw: clk_hw for the pll
+ * @pll_data: PLL driver specific data
+ */
+struct clk_pll {
+	struct clk_hw hw;
+	struct clk_pll_data *pll_data;
+};
+
+#define to_clk_pll(_hw) container_of(_hw, struct clk_pll, hw)
+
+static unsigned long clk_pllclk_recalc(struct clk_hw *hw,
+					unsigned long parent_rate)
+{
+	struct clk_pll *pll = to_clk_pll(hw);
+	struct clk_pll_data *pll_data = pll->pll_data;
+	unsigned long rate = parent_rate;
+	u32  mult = 0, prediv, postdiv, val;
+
+	/*
+	 * get bits 0-5 of multiplier from pllctrl PLLM register
+	 * if has_pllctrl is non zero
+	 */
+	if (pll_data->has_pllctrl) {
+		val = readl(pll_data->pllm);
+		mult = (val & pll_data->pllm_lower_mask);
+	}
+
+	/* bit6-12 of PLLM is in Main PLL control register */
+	val = readl(pll_data->pll_ctl0);
+	mult |= ((val & pll_data->pllm_upper_mask)
+			>> pll_data->pllm_upper_shift);
+	prediv = (val & pll_data->plld_mask);
+	postdiv = pll_data->postdiv;
+
+	rate /= (prediv + 1);
+	rate = (rate * (mult + 1));
+	rate /= postdiv;
+
+	return rate;
+}
+
+static const struct clk_ops clk_pll_ops = {
+	.recalc_rate = clk_pllclk_recalc,
+};
+
+static struct clk *clk_register_pll(struct device *dev,
+			const char *name,
+			const char *parent_name,
+			struct clk_pll_data *pll_data)
+{
+	struct clk_init_data init;
+	struct clk_pll *pll;
+	struct clk *clk;
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = &clk_pll_ops;
+	init.flags = 0;
+	init.parent_names = (parent_name ? &parent_name : NULL);
+	init.num_parents = (parent_name ? 1 : 0);
+
+	pll->pll_data	= pll_data;
+	pll->hw.init = &init;
+
+	clk = clk_register(NULL, &pll->hw);
+	if (IS_ERR(clk))
+		goto out;
+
+	return clk;
+out:
+	kfree(pll);
+	return NULL;
+}
+
+/**
+ * _of_clk_init - PLL initialisation via DT
+ * @node: device tree node for this clock
+ * @pllctrl: If true, lower 6 bits of multiplier is in pllm register of
+ *		pll controller, else it is in the control regsiter0(bit 11-6)
+ */
+static void __init _of_pll_clk_init(struct device_node *node, bool pllctrl)
+{
+	struct clk_pll_data *pll_data;
+	const char *parent_name;
+	struct clk *clk;
+	int i;
+
+	pll_data = kzalloc(sizeof(*pll_data), GFP_KERNEL);
+	if (!pll_data) {
+		pr_err("%s: Out of memory\n", __func__);
+		return;
+	}
+
+	parent_name = of_clk_get_parent_name(node, 0);
+	if (of_property_read_u32(node, "fixed-postdiv",	&pll_data->postdiv))
+		goto out;
+
+	i = of_property_match_string(node, "reg-names", "control");
+	pll_data->pll_ctl0 = of_iomap(node, i);
+	if (!pll_data->pll_ctl0) {
+		pr_err("%s: ioremap failed\n", __func__);
+		goto out;
+	}
+
+	pll_data->pllm_lower_mask = PLLM_LOW_MASK;
+	pll_data->pllm_upper_shift = PLLM_HIGH_SHIFT;
+	pll_data->plld_mask = PLLD_MASK;
+	pll_data->has_pllctrl = pllctrl;
+	if (!pll_data->has_pllctrl) {
+		pll_data->pllm_upper_mask = PLLM_HIGH_MASK;
+	} else {
+		pll_data->pllm_upper_mask = MAIN_PLLM_HIGH_MASK;
+		i = of_property_match_string(node, "reg-names", "multiplier");
+		pll_data->pllm = of_iomap(node, i);
+		if (!pll_data->pllm) {
+			iounmap(pll_data->pll_ctl0);
+			goto out;
+		}
+	}
+
+	clk = clk_register_pll(NULL, node->name, parent_name, pll_data);
+	if (clk) {
+		of_clk_add_provider(node, of_clk_src_simple_get, clk);
+		return;
+	}
+
+out:
+	pr_err("%s: error initializing pll %s\n", __func__, node->name);
+	kfree(pll_data);
+}
+
+/**
+ * of_keystone_pll_clk_init - PLL initialisation DT wrapper
+ * @node: device tree node for this clock
+ */
+static void __init of_keystone_pll_clk_init(struct device_node *node)
+{
+	_of_pll_clk_init(node, false);
+}
+CLK_OF_DECLARE(keystone_pll_clock, "ti,keystone,pll-clock",
+					of_keystone_pll_clk_init);
+
+/**
+ * of_keystone_pll_main_clk_init - Main PLL initialisation DT wrapper
+ * @node: device tree node for this clock
+ */
+static void __init of_keystone_main_pll_clk_init(struct device_node *node)
+{
+	_of_pll_clk_init(node, true);
+}
+CLK_OF_DECLARE(keystone_main_pll_clock, "ti,keystone,main-pll-clock",
+						of_keystone_main_pll_clk_init);
+
+/**
+ * of_pll_div_clk_init - PLL divider setup function
+ * @node: device tree node for this clock
+ */
+static void __init of_pll_div_clk_init(struct device_node *node)
+{
+	const char *parent_name;
+	void __iomem *reg;
+	u32 shift, mask;
+	struct clk *clk;
+	const char *clk_name = node->name;
+
+	of_property_read_string(node, "clock-output-names", &clk_name);
+	reg = of_iomap(node, 0);
+	if (!reg) {
+		pr_err("%s: ioremap failed\n", __func__);
+		return;
+	}
+
+	parent_name = of_clk_get_parent_name(node, 0);
+	if (!parent_name) {
+		pr_err("%s: missing parent clock\n", __func__);
+		return;
+	}
+
+	if (of_property_read_u32(node, "bit-shift", &shift)) {
+		pr_err("%s: missing 'shift' property\n", __func__);
+		return;
+	}
+
+	if (of_property_read_u32(node, "bit-mask", &mask)) {
+		pr_err("%s: missing 'bit-mask' property\n", __func__);
+		return;
+	}
+
+	clk = clk_register_divider(NULL, clk_name, parent_name, 0, reg, shift,
+				 mask, 0, NULL);
+	if (clk)
+		of_clk_add_provider(node, of_clk_src_simple_get, clk);
+	else
+		pr_err("%s: error registering divider %s\n", __func__, clk_name);
+}
+CLK_OF_DECLARE(pll_divider_clock, "ti,keystone,pll-divider-clock", of_pll_div_clk_init);
+
+/**
+ * of_pll_mux_clk_init - PLL mux setup function
+ * @node: device tree node for this clock
+ */
+static void __init of_pll_mux_clk_init(struct device_node *node)
+{
+	void __iomem *reg;
+	u32 shift, mask;
+	struct clk *clk;
+	const char *parents[2];
+	const char *clk_name = node->name;
+
+	of_property_read_string(node, "clock-output-names", &clk_name);
+	reg = of_iomap(node, 0);
+	if (!reg) {
+		pr_err("%s: ioremap failed\n", __func__);
+		return;
+	}
+
+	parents[0] = of_clk_get_parent_name(node, 0);
+	parents[1] = of_clk_get_parent_name(node, 1);
+	if (!parents[0] || !parents[1]) {
+		pr_err("%s: missing parent clocks\n", __func__);
+		return;
+	}
+
+	if (of_property_read_u32(node, "bit-shift", &shift)) {
+		pr_err("%s: missing 'shift' property\n", __func__);
+		return;
+	}
+
+	if (of_property_read_u32(node, "bit-mask", &mask)) {
+		pr_err("%s: missing 'bit-mask' property\n", __func__);
+		return;
+	}
+
+	clk = clk_register_mux(NULL, clk_name, (const char **)&parents,
+				ARRAY_SIZE(parents) , 0, reg, shift, mask,
+				0, NULL);
+	if (clk)
+		of_clk_add_provider(node, of_clk_src_simple_get, clk);
+	else
+		pr_err("%s: error registering mux %s\n", __func__, clk_name);
+}
+CLK_OF_DECLARE(pll_mux_clock, "ti,keystone,pll-mux-clock", of_pll_mux_clk_init);