[PATCH 4/9] clk: imx: add pllv4 support

[Dong Aisheng]

pllv4 is designed for System Clock Generation (SCG) module observed
in IMX ULP SoC series. e.g. i.MX7ULP.

The SCG modules generates clock used to derive processor, system,
peripheral bus and external memory interface clocks while this patch
intends to support the PLL part.

Cc: Stephen Boyd <sboyd at codeaurora.org>
Cc: Michael Turquette <mturquette at baylibre.com>
Cc: Shawn Guo <shawnguo at kernel.org>
Cc: Anson Huang <Anson.Huang at nxp.com>
Cc: Bai Ping <ping.bai at nxp.com>
Signed-off-by: Dong Aisheng <aisheng.dong at nxp.com>
---
 drivers/clk/imx/Makefile    |   1 +
 drivers/clk/imx/clk-pllv4.c | 196 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/clk/imx/clk.h       |   3 +
 3 files changed, 200 insertions(+)
 create mode 100644 drivers/clk/imx/clk-pllv4.c

diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
index 1ada68a..1e308e2 100644
--- a/drivers/clk/imx/Makefile
+++ b/drivers/clk/imx/Makefile
@@ -10,6 +10,7 @@ obj-y += \
 	clk-pllv1.o \
 	clk-pllv2.o \
 	clk-pllv3.o \
+	clk-pllv4.o \
 	clk-pfd.o
 
 obj-$(CONFIG_SOC_IMX1)   += clk-imx1.o
diff --git a/drivers/clk/imx/clk-pllv4.c b/drivers/clk/imx/clk-pllv4.c
new file mode 100644
index 0000000..502da64
--- /dev/null
+++ b/drivers/clk/imx/clk-pllv4.c
@@ -0,0 +1,196 @@
+/*
+ * Copyright (C) 2016 Freescale Semiconductor, Inc.
+ * Copyright 2017 NXP
+ *
+ * Author: Dong Aisheng <aisheng.dong at nxp.com>
+ *
+ * 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.
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+
+/* PLL Control Status Register (xPLLCSR) */
+#define PLL_CSR_OFFSET		0x0
+#define PLL_VLD			BIT(24)
+#define PLL_EN			BIT(0)
+
+/* PLL Configuration Register (xPLLCFG) */
+#define PLL_CFG_OFFSET		0x08
+#define BP_PLL_MULT		16
+#define BM_PLL_MULT		(0x7f << 16)
+
+/* PLL Numerator Register (xPLLNUM) */
+#define PLL_NUM_OFFSET		0x10
+
+/* PLL Denominator Register (xPLLDENOM) */
+#define PLL_DENOM_OFFSET	0x14
+
+struct clk_pllv4 {
+	struct clk_hw	hw;
+	void __iomem	*base;
+};
+
+/* Valid PLL MULT Table */
+static const int pllv4_mult_table[] = {33, 27, 22, 20, 17, 16};
+
+#define to_clk_pllv4(__hw) container_of(__hw, struct clk_pllv4, hw)
+
+static int clk_pllv4_wait_lock(struct clk_pllv4 *pll)
+{
+	unsigned long timeout = jiffies + msecs_to_jiffies(5);
+
+	/* Wait for PLL to lock */
+	do {
+		if (readl_relaxed(pll->base  + PLL_CSR_OFFSET) & PLL_VLD)
+			break;
+		if (time_after(jiffies, timeout))
+			break;
+			usleep_range(50, 500);
+	} while (1);
+
+	return readl_relaxed(pll->base + PLL_CSR_OFFSET) & PLL_VLD ?
+	       0 : -ETIMEDOUT;
+}
+
+static int clk_pllv4_is_enabled(struct clk_hw *hw)
+{
+	struct clk_pllv4 *pll = to_clk_pllv4(hw);
+
+	if (readl_relaxed(pll->base) & PLL_EN)
+		return 1;
+
+	return 0;
+}
+
+static unsigned long clk_pllv4_recalc_rate(struct clk_hw *hw,
+					   unsigned long parent_rate)
+{
+	struct clk_pllv4 *pll = to_clk_pllv4(hw);
+	u32 div;
+
+	div = (readl_relaxed(pll->base + PLL_CFG_OFFSET)
+	       & BM_PLL_MULT) >> BP_PLL_MULT;
+
+	return parent_rate * div;
+}
+
+static long clk_pllv4_round_rate(struct clk_hw *hw, unsigned long rate,
+				 unsigned long *prate)
+{
+	unsigned long parent_rate = *prate;
+	unsigned long round_rate, i;
+
+	for (i = 0; i < ARRAY_SIZE(pllv4_mult_table); i++) {
+		round_rate = parent_rate * pllv4_mult_table[i];
+		if (rate >= round_rate)
+			return round_rate;
+	}
+
+	return round_rate;
+}
+
+static bool clk_pllv4_is_valid_mult(unsigned int mult)
+{
+	int i;
+
+	/* check if mult is in valid MULT table */
+	for (i = 0; i < ARRAY_SIZE(pllv4_mult_table); i++) {
+		if (pllv4_mult_table[i] == mult)
+			return true;
+	}
+
+	return false;
+}
+
+static int clk_pllv4_set_rate(struct clk_hw *hw, unsigned long rate,
+			      unsigned long parent_rate)
+{
+	struct clk_pllv4 *pll = to_clk_pllv4(hw);
+	u32 val, mult;
+
+	if (clk_pllv4_is_enabled(hw)) {
+		WARN(1, "clk_pllv4: can't change rate when pll is enabled");
+		return -EINVAL;
+	}
+
+	mult = rate / parent_rate;
+
+	if (clk_pllv4_is_valid_mult(mult))
+		return -EINVAL;
+
+	val = readl_relaxed(pll->base + PLL_CFG_OFFSET);
+	val &= ~BM_PLL_MULT;
+	val |= mult << BP_PLL_MULT;
+	writel_relaxed(val, pll->base + PLL_CFG_OFFSET);
+
+	return 0;
+}
+
+static int clk_pllv4_enable(struct clk_hw *hw)
+{
+	u32 val;
+	struct clk_pllv4 *pll = to_clk_pllv4(hw);
+
+	val = readl_relaxed(pll->base);
+	val |= PLL_EN;
+	writel_relaxed(val, pll->base);
+
+	return clk_pllv4_wait_lock(pll);
+}
+
+static void clk_pllv4_disable(struct clk_hw *hw)
+{
+	u32 val;
+	struct clk_pllv4 *pll = to_clk_pllv4(hw);
+
+	val = readl_relaxed(pll->base);
+	val &= ~PLL_EN;
+	writel_relaxed(val, pll->base);
+}
+
+static const struct clk_ops clk_pllv4_ops = {
+	.recalc_rate	= clk_pllv4_recalc_rate,
+	.round_rate	= clk_pllv4_round_rate,
+	.set_rate	= clk_pllv4_set_rate,
+	.enable		= clk_pllv4_enable,
+	.disable	= clk_pllv4_disable,
+	.is_enabled	= clk_pllv4_is_enabled,
+};
+
+struct clk *imx_clk_pllv4(const char *name, const char *parent_name,
+			  void __iomem *base)
+{
+	struct clk_pllv4 *pll;
+	struct clk *clk;
+	struct clk_init_data init;
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	pll->base = base;
+
+	init.name = name;
+	init.ops = &clk_pllv4_ops;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+	init.flags = CLK_SET_RATE_GATE;
+
+	pll->hw.init = &init;
+
+	clk = clk_register(NULL, &pll->hw);
+	if (IS_ERR(clk))
+		kfree(pll);
+
+	return clk;
+}
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index e1f5e42..f599732 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -40,6 +40,9 @@ enum imx_pllv3_type {
 struct clk *imx_clk_pllv3(enum imx_pllv3_type type, const char *name,
 		const char *parent_name, void __iomem *base, u32 div_mask);
 
+struct clk *imx_clk_pllv4(const char *name, const char *parent_name,
+			  void __iomem *base);
+
 struct clk *clk_register_gate2(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
 		void __iomem *reg, u8 bit_idx, u8 cgr_val,
-- 
2.7.4