clk: axs10x: introduce AXS10X pll driver

AXS10X boards manages it's clocks using various PLLs. These PLL has same
dividers and corresponding control registers mapped to different addresses.
So we add one common driver for such PLLs.

Each PLL on AXS10X board consist of three dividers: IDIV, FBDIV and
ODIV. Output clock value is managed using these dividers.

We add pre-defined tables with supported rate values and appropriate
configurations of IDIV, FBDIV and ODIV for each value.

As of today we add support for PLLs that generate clock for the
following devices:
 * ARC core on AXC CPU tiles.
 * ARC PGU on ARC SDP Mainboard.
and more to come later.

By this patch we add support for two plls (arc core pll and pgu pll),
so we had to use two different init types: CLK_OF_DECLARE for arc core pll and
regular probing for pgu pll.
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vlad Zakharov <vzakhar@synopsys.com>
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
[sboyd@codeaurora.org: Silence dubious !x & y sparse warning,
make of_axs10x_pll_clk_setup() unregister clk on failure]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

Documentation/devicetree/bindings/clock/snps,pll-clock.txt

+Binding for the AXS10X Generic PLL clock
+
+This binding uses the common clock binding[1].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+Required properties:
+- compatible: should be "snps,axs10x-<name>-pll-clock"
+  "snps,axs10x-arc-pll-clock"
+  "snps,axs10x-pgu-pll-clock"
+- reg: should always contain 2 pairs address - length: first for PLL config
+registers and second for corresponding LOCK CGU register.
+- clocks: shall be the input parent clock phandle for the PLL.
+- #clock-cells: from common clock binding; Should always be set to 0.
+
+Example:
+	input-clk: input-clk {
+		clock-frequency = <33333333>;
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+	};
+
+	core-clk: core-clk@80 {
+		compatible = "snps,axs10x-arc-pll-clock";
+		reg = <0x80 0x10>, <0x100 0x10>;
+		#clock-cells = <0>;
+		clocks = <&input-clk>;
+	};

MAINTAINERS

@@ -12745,6 +12745,12 @@ F:	arch/arc/plat-axs10x
 F:	arch/arc/boot/dts/ax*
 F:	Documentation/devicetree/bindings/arc/axs10*
 
+SYNOPSYS ARC SDP clock driver
+M:	Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
+S:	Supported
+F:	drivers/clk/axs10x/*
+F:	Documentation/devicetree/bindings/clock/snps,pll-clock.txt
+
 SYSTEM CONFIGURATION (SYSCON)
 M:	Lee Jones <lee.jones@linaro.org>
 M:	Arnd Bergmann <arnd@arndb.de>

drivers/clk/axs10x/Makefile

 obj-y += i2s_pll_clock.o
+obj-y += pll_clock.o

drivers/clk/axs10x/pll_clock.c

+/*
+ * Synopsys AXS10X SDP Generic PLL clock driver
+ *
+ * Copyright (C) 2017 Synopsys
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+
+/* PLL registers addresses */
+#define PLL_REG_IDIV	0x0
+#define PLL_REG_FBDIV	0x4
+#define PLL_REG_ODIV	0x8
+
+/*
+ * Bit fields of the PLL IDIV/FBDIV/ODIV registers:
+ *  ________________________________________________________________________
+ * |31                15|    14    |   13   |  12  |11         6|5         0|
+ * |-------RESRVED------|-NOUPDATE-|-BYPASS-|-EDGE-|--HIGHTIME--|--LOWTIME--|
+ * |____________________|__________|________|______|____________|___________|
+ *
+ * Following macros determine the way of access to these registers
+ * They should be set up only using the macros.
+ * reg should be an u32 variable.
+ */
+
+#define PLL_REG_GET_LOW(reg)			\
+	(((reg) & (0x3F << 0)) >> 0)
+#define PLL_REG_GET_HIGH(reg)			\
+	(((reg) & (0x3F << 6)) >> 6)
+#define PLL_REG_GET_EDGE(reg)			\
+	(((reg) & (BIT(12))) ? 1 : 0)
+#define PLL_REG_GET_BYPASS(reg)			\
+	(((reg) & (BIT(13))) ? 1 : 0)
+#define PLL_REG_GET_NOUPD(reg)			\
+	(((reg) & (BIT(14))) ? 1 : 0)
+#define PLL_REG_GET_PAD(reg)			\
+	(((reg) & (0x1FFFF << 15)) >> 15)
+
+#define PLL_REG_SET_LOW(reg, value)		\
+	{ reg |= (((value) & 0x3F) << 0); }
+#define PLL_REG_SET_HIGH(reg, value)		\
+	{ reg |= (((value) & 0x3F) << 6); }
+#define PLL_REG_SET_EDGE(reg, value)		\
+	{ reg |= (((value) & 0x01) << 12); }
+#define PLL_REG_SET_BYPASS(reg, value)		\
+	{ reg |= (((value) & 0x01) << 13); }
+#define PLL_REG_SET_NOUPD(reg, value)		\
+	{ reg |= (((value) & 0x01) << 14); }
+#define PLL_REG_SET_PAD(reg, value)		\
+	{ reg |= (((value) & 0x1FFFF) << 15); }
+
+#define PLL_LOCK	BIT(0)
+#define PLL_ERROR	BIT(1)
+#define PLL_MAX_LOCK_TIME 100 /* 100 us */
+
+struct axs10x_pll_cfg {
+	u32 rate;
+	u32 idiv;
+	u32 fbdiv;
+	u32 odiv;
+};
+
+static const struct axs10x_pll_cfg arc_pll_cfg[] = {
+	{ 33333333,  1, 1,  1 },
+	{ 50000000,  1, 30, 20 },
+	{ 75000000,  2, 45, 10 },
+	{ 90000000,  2, 54, 10 },
+	{ 100000000, 1, 30, 10 },
+	{ 125000000, 2, 45, 6 },
+	{}
+};
+
+static const struct axs10x_pll_cfg pgu_pll_cfg[] = {
+	{ 25200000, 1, 84, 90 },
+	{ 50000000, 1, 100, 54 },
+	{ 74250000, 1, 44, 16 },
+	{}
+};
+
+struct axs10x_pll_clk {
+	struct clk_hw hw;
+	void __iomem *base;
+	void __iomem *lock;
+	const struct axs10x_pll_cfg *pll_cfg;
+	struct device *dev;
+};
+
+static inline void axs10x_pll_write(struct axs10x_pll_clk *clk, u32 reg,
+				    u32 val)
+{
+	iowrite32(val, clk->base + reg);
+}
+
+static inline u32 axs10x_pll_read(struct axs10x_pll_clk *clk, u32 reg)
+{
+	return ioread32(clk->base + reg);
+}
+
+static inline struct axs10x_pll_clk *to_axs10x_pll_clk(struct clk_hw *hw)
+{
+	return container_of(hw, struct axs10x_pll_clk, hw);
+}
+
+static inline u32 axs10x_div_get_value(u32 reg)
+{
+	if (PLL_REG_GET_BYPASS(reg))
+		return 1;
+
+	return PLL_REG_GET_HIGH(reg) + PLL_REG_GET_LOW(reg);
+}
+
+static inline u32 axs10x_encode_div(unsigned int id, int upd)
+{
+	u32 div = 0;
+
+	PLL_REG_SET_LOW(div, (id % 2 == 0) ? id >> 1 : (id >> 1) + 1);
+	PLL_REG_SET_HIGH(div, id >> 1);
+	PLL_REG_SET_EDGE(div, id % 2);
+	PLL_REG_SET_BYPASS(div, id == 1 ? 1 : 0);
+	PLL_REG_SET_NOUPD(div, upd == 0 ? 1 : 0);
+
+	return div;
+}
+
+static unsigned long axs10x_pll_recalc_rate(struct clk_hw *hw,
+					    unsigned long parent_rate)
+{
+	u64 rate;
+	u32 idiv, fbdiv, odiv;
+	struct axs10x_pll_clk *clk = to_axs10x_pll_clk(hw);
+
+	idiv = axs10x_div_get_value(axs10x_pll_read(clk, PLL_REG_IDIV));
+	fbdiv = axs10x_div_get_value(axs10x_pll_read(clk, PLL_REG_FBDIV));
+	odiv = axs10x_div_get_value(axs10x_pll_read(clk, PLL_REG_ODIV));
+
+	rate = (u64)parent_rate * fbdiv;
+	do_div(rate, idiv * odiv);
+
+	return rate;
+}
+
+static long axs10x_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long *prate)
+{
+	int i;
+	long best_rate;
+	struct axs10x_pll_clk *clk = to_axs10x_pll_clk(hw);
+	const struct axs10x_pll_cfg *pll_cfg = clk->pll_cfg;
+
+	if (pll_cfg[0].rate == 0)
+		return -EINVAL;
+
+	best_rate = pll_cfg[0].rate;
+
+	for (i = 1; pll_cfg[i].rate != 0; i++) {
+		if (abs(rate - pll_cfg[i].rate) < abs(rate - best_rate))
+			best_rate = pll_cfg[i].rate;
+	}
+
+	return best_rate;
+}
+
+static int axs10x_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+			       unsigned long parent_rate)
+{
+	int i;
+	struct axs10x_pll_clk *clk = to_axs10x_pll_clk(hw);
+	const struct axs10x_pll_cfg *pll_cfg = clk->pll_cfg;
+
+	for (i = 0; pll_cfg[i].rate != 0; i++) {
+		if (pll_cfg[i].rate == rate) {
+			axs10x_pll_write(clk, PLL_REG_IDIV,
+					 axs10x_encode_div(pll_cfg[i].idiv, 0));
+			axs10x_pll_write(clk, PLL_REG_FBDIV,
+					 axs10x_encode_div(pll_cfg[i].fbdiv, 0));
+			axs10x_pll_write(clk, PLL_REG_ODIV,
+					 axs10x_encode_div(pll_cfg[i].odiv, 1));
+
+			/*
+			 * Wait until CGU relocks and check error status.
+			 * If after timeout CGU is unlocked yet return error
+			 */
+			udelay(PLL_MAX_LOCK_TIME);
+			if (!(ioread32(clk->lock) & PLL_LOCK))
+				return -ETIMEDOUT;
+
+			if (ioread32(clk->lock) & PLL_ERROR)
+				return -EINVAL;
+
+			return 0;
+		}
+	}
+
+	dev_err(clk->dev, "invalid rate=%ld, parent_rate=%ld\n", rate,
+			parent_rate);
+	return -EINVAL;
+}
+
+static const struct clk_ops axs10x_pll_ops = {
+	.recalc_rate = axs10x_pll_recalc_rate,
+	.round_rate = axs10x_pll_round_rate,
+	.set_rate = axs10x_pll_set_rate,
+};
+
+static int axs10x_pll_clk_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const char *parent_name;
+	struct axs10x_pll_clk *pll_clk;
+	struct resource *mem;
+	struct clk_init_data init = { };
+	int ret;
+
+	pll_clk = devm_kzalloc(dev, sizeof(*pll_clk), GFP_KERNEL);
+	if (!pll_clk)
+		return -ENOMEM;
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pll_clk->base = devm_ioremap_resource(dev, mem);
+	if (IS_ERR(pll_clk->base))
+		return PTR_ERR(pll_clk->base);
+
+	mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	pll_clk->lock = devm_ioremap_resource(dev, mem);
+	if (IS_ERR(pll_clk->lock))
+		return PTR_ERR(pll_clk->lock);
+
+	init.name = dev->of_node->name;
+	init.ops = &axs10x_pll_ops;
+	parent_name = of_clk_get_parent_name(dev->of_node, 0);
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+	pll_clk->hw.init = &init;
+	pll_clk->dev = dev;
+	pll_clk->pll_cfg = of_device_get_match_data(dev);
+
+	if (!pll_clk->pll_cfg) {
+		dev_err(dev, "No OF match data provided\n");
+		return -EINVAL;
+	}
+
+	ret = devm_clk_hw_register(dev, &pll_clk->hw);
+	if (ret) {
+		dev_err(dev, "failed to register %s clock\n", init.name);
+		return ret;
+	}
+
+	return of_clk_add_hw_provider(dev->of_node, of_clk_hw_simple_get,
+			&pll_clk->hw);
+}
+
+static int axs10x_pll_clk_remove(struct platform_device *pdev)
+{
+	of_clk_del_provider(pdev->dev.of_node);
+	return 0;
+}
+
+static void __init of_axs10x_pll_clk_setup(struct device_node *node)
+{
+	const char *parent_name;
+	struct axs10x_pll_clk *pll_clk;
+	struct clk_init_data init = { };
+	int ret;
+
+	pll_clk = kzalloc(sizeof(*pll_clk), GFP_KERNEL);
+	if (!pll_clk)
+		return;
+
+	pll_clk->base = of_iomap(node, 0);
+	if (!pll_clk->base) {
+		pr_err("failed to map pll div registers\n");
+		goto err_free_pll_clk;
+	}
+
+	pll_clk->lock = of_iomap(node, 1);
+	if (!pll_clk->lock) {
+		pr_err("failed to map pll lock register\n");
+		goto err_unmap_base;
+	}
+
+	init.name = node->name;
+	init.ops = &axs10x_pll_ops;
+	parent_name = of_clk_get_parent_name(node, 0);
+	init.parent_names = &parent_name;
+	init.num_parents = parent_name ? 1 : 0;
+	pll_clk->hw.init = &init;
+	pll_clk->pll_cfg = arc_pll_cfg;
+
+	ret = clk_hw_register(NULL, &pll_clk->hw);
+	if (ret) {
+		pr_err("failed to register %s clock\n", node->name);
+		goto err_unmap_lock;
+	}
+
+	ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, &pll_clk->hw);
+	if (ret) {
+		pr_err("failed to add hw provider for %s clock\n", node->name);
+		goto err_unregister_clk;
+	}
+
+	return;
+
+err_unregister_clk:
+	clk_hw_unregister(&pll_clk->hw);
+err_unmap_lock:
+	iounmap(pll_clk->lock);
+err_unmap_base:
+	iounmap(pll_clk->base);
+err_free_pll_clk:
+	kfree(pll_clk);
+}
+CLK_OF_DECLARE(axs10x_pll_clock, "snps,axs10x-arc-pll-clock",
+	       of_axs10x_pll_clk_setup);
+
+static const struct of_device_id axs10x_pll_clk_id[] = {
+	{ .compatible = "snps,axs10x-pgu-pll-clock", .data = &pgu_pll_cfg},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, axs10x_pll_clk_id);
+
+static struct platform_driver axs10x_pll_clk_driver = {
+	.driver = {
+		.name = "axs10x-pll-clock",
+		.of_match_table = axs10x_pll_clk_id,
+	},
+	.probe = axs10x_pll_clk_probe,
+	.remove = axs10x_pll_clk_remove,
+};
+builtin_platform_driver(axs10x_pll_clk_driver);
+
+MODULE_AUTHOR("Vlad Zakharov <vzakhar@synopsys.com>");
+MODULE_DESCRIPTION("Synopsys AXS10X SDP Generic PLL Clock Driver");
+MODULE_LICENSE("GPL v2");