clk: intel: Add CGU clock driver for a new SoC

Clock Generation Unit(CGU) is a new clock controller IP of a forthcoming
Intel network processor SoC named Lightning Mountain(LGM). It provides
programming interfaces to control & configure all CPU & peripheral clocks.
Add common clock framework based clock controller driver for CGU.

Signed-off-by: Rahul Tanwar <[email protected]>
Link: https://lkml.kernel.org/r/42a4f71847714df482bacffdcd84341a4052800b.1587102634.git.rahul.tanwar@linux.intel.com
[[email protected]: Kill init function to alloc and cleanup newline]
Signed-off-by: Stephen Boyd <[email protected]>

Author: Rahul Tanwar

drivers/clk/Kconfig

@@ -360,6 +360,7 @@ source "drivers/clk/sunxi-ng/Kconfig"
 source "drivers/clk/tegra/Kconfig"
 source "drivers/clk/ti/Kconfig"
 source "drivers/clk/uniphier/Kconfig"
+source "drivers/clk/x86/Kconfig"
 source "drivers/clk/zynqmp/Kconfig"
 
 endmenu

drivers/clk/x86/Kconfig

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config CLK_LGM_CGU
+	depends on OF && HAS_IOMEM && (X86 || COMPILE_TEST)
+	select OF_EARLY_FLATTREE
+	bool "Clock driver for Lightning Mountain(LGM) platform"
+	help
+	  Clock Generation Unit(CGU) driver for Intel Lightning Mountain(LGM)
+	  network processor SoC.

drivers/clk/x86/Makefile

@@ -3,3 +3,4 @@ obj-$(CONFIG_PMC_ATOM)		+= clk-pmc-atom.o
 obj-$(CONFIG_X86_AMD_PLATFORM_DEVICE)	+= clk-st.o
 clk-x86-lpss-objs		:= clk-lpt.o
 obj-$(CONFIG_X86_INTEL_LPSS)	+= clk-x86-lpss.o
+obj-$(CONFIG_CLK_LGM_CGU)	+= clk-cgu.o clk-cgu-pll.o clk-lgm.o

drivers/clk/x86/clk-cgu-pll.c

@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Intel Corporation.
+ * Zhu YiXin <[email protected]>
+ * Rahul Tanwar <[email protected]>
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/iopoll.h>
+#include <linux/of.h>
+
+#include "clk-cgu.h"
+
+#define to_lgm_clk_pll(_hw)	container_of(_hw, struct lgm_clk_pll, hw)
+#define PLL_REF_DIV(x)		((x) + 0x08)
+
+/*
+ * Calculate formula:
+ * rate = (prate * mult + (prate * frac) / frac_div) / div
+ */
+static unsigned long
+lgm_pll_calc_rate(unsigned long prate, unsigned int mult,
+		  unsigned int div, unsigned int frac, unsigned int frac_div)
+{
+	u64 crate, frate, rate64;
+
+	rate64 = prate;
+	crate = rate64 * mult;
+	frate = rate64 * frac;
+	do_div(frate, frac_div);
+	crate += frate;
+	do_div(crate, div);
+
+	return crate;
+}
+
+static unsigned long lgm_pll_recalc_rate(struct clk_hw *hw, unsigned long prate)
+{
+	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
+	unsigned int div, mult, frac;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pll->lock, flags);
+	mult = lgm_get_clk_val(pll->membase, PLL_REF_DIV(pll->reg), 0, 12);
+	div = lgm_get_clk_val(pll->membase, PLL_REF_DIV(pll->reg), 18, 6);
+	frac = lgm_get_clk_val(pll->membase, pll->reg, 2, 24);
+	spin_unlock_irqrestore(&pll->lock, flags);
+
+	if (pll->type == TYPE_LJPLL)
+		div *= 4;
+
+	return lgm_pll_calc_rate(prate, mult, div, frac, BIT(24));
+}
+
+static int lgm_pll_is_enabled(struct clk_hw *hw)
+{
+	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
+	unsigned long flags;
+	unsigned int ret;
+
+	spin_lock_irqsave(&pll->lock, flags);
+	ret = lgm_get_clk_val(pll->membase, pll->reg, 0, 1);
+	spin_unlock_irqrestore(&pll->lock, flags);
+
+	return ret;
+}
+
+static int lgm_pll_enable(struct clk_hw *hw)
+{
+	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
+	unsigned long flags;
+	u32 val;
+	int ret;
+
+	spin_lock_irqsave(&pll->lock, flags);
+	lgm_set_clk_val(pll->membase, pll->reg, 0, 1, 1);
+	ret = readl_poll_timeout_atomic(pll->membase + pll->reg,
+					val, (val & 0x1), 1, 100);
+	spin_unlock_irqrestore(&pll->lock, flags);
+
+	return ret;
+}
+
+static void lgm_pll_disable(struct clk_hw *hw)
+{
+	struct lgm_clk_pll *pll = to_lgm_clk_pll(hw);
+	unsigned long flags;
+
+	spin_lock_irqsave(&pll->lock, flags);
+	lgm_set_clk_val(pll->membase, pll->reg, 0, 1, 0);
+	spin_unlock_irqrestore(&pll->lock, flags);
+}
+
+static const struct clk_ops lgm_pll_ops = {
+	.recalc_rate = lgm_pll_recalc_rate,
+	.is_enabled = lgm_pll_is_enabled,
+	.enable = lgm_pll_enable,
+	.disable = lgm_pll_disable,
+};
+
+static struct clk_hw *
+lgm_clk_register_pll(struct lgm_clk_provider *ctx,
+		     const struct lgm_pll_clk_data *list)
+{
+	struct clk_init_data init = {};
+	struct lgm_clk_pll *pll;
+	struct device *dev = ctx->dev;
+	struct clk_hw *hw;
+	int ret;
+
+	init.ops = &lgm_pll_ops;
+	init.name = list->name;
+	init.flags = list->flags;
+	init.parent_data = list->parent_data;
+	init.num_parents = list->num_parents;
+
+	pll = devm_kzalloc(dev, sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	pll->membase = ctx->membase;
+	pll->lock = ctx->lock;
+	pll->reg = list->reg;
+	pll->flags = list->flags;
+	pll->type = list->type;
+	pll->hw.init = &init;
+
+	hw = &pll->hw;
+	ret = clk_hw_register(dev, hw);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return hw;
+}
+
+int lgm_clk_register_plls(struct lgm_clk_provider *ctx,
+			  const struct lgm_pll_clk_data *list,
+			  unsigned int nr_clk)
+{
+	struct clk_hw *hw;
+	int i;
+
+	for (i = 0; i < nr_clk; i++, list++) {
+		hw = lgm_clk_register_pll(ctx, list);
+		if (IS_ERR(hw)) {
+			dev_err(ctx->dev, "failed to register pll: %s\n",
+				list->name);
+			return PTR_ERR(hw);
+		}
+		ctx->clk_data.hws[list->id] = hw;
+	}
+
+	return 0;
+}