clk: mediatek: Add initial common clock support for Mediatek SoCs.

This patch adds common clock support for Mediatek SoCs, including plls,
muxes and clock gates.

Signed-off-by: James Liao <jamesjj.liao@mediatek.com>
Signed-off-by: Henry Chen <henryc.chen@mediatek.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
[sboyd@codeaurora.org: Squelch checkpatch warning in clk-mtk.h]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

1 files changed, 332 insertions, 0 deletions

diff --git a/drivers/clk/mediatek/clk-pll.c b/drivers/clk/mediatek/clk-pll.c
new file mode 100644
index 000000000000..66154caf992a
--- /dev/null
+++ b/drivers/clk/mediatek/clk-pll.c
@@ -0,0 +1,332 @@
+/*
+ * Copyright (c) 2014 MediaTek Inc.
+ * Author: James Liao <jamesjj.liao@mediatek.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/clkdev.h>
+#include <linux/delay.h>
+
+#include "clk-mtk.h"
+
+#define REG_CON0		0
+#define REG_CON1		4
+
+#define CON0_BASE_EN		BIT(0)
+#define CON0_PWR_ON		BIT(0)
+#define CON0_ISO_EN		BIT(1)
+#define CON0_PCW_CHG		BIT(31)
+
+#define AUDPLL_TUNER_EN		BIT(31)
+
+#define POSTDIV_MASK		0x7
+#define INTEGER_BITS		7
+
+/*
+ * MediaTek PLLs are configured through their pcw value. The pcw value describes
+ * a divider in the PLL feedback loop which consists of 7 bits for the integer
+ * part and the remaining bits (if present) for the fractional part. Also they
+ * have a 3 bit power-of-two post divider.
+ */
+
+struct mtk_clk_pll {
+	struct clk_hw	hw;
+	void __iomem	*base_addr;
+	void __iomem	*pd_addr;
+	void __iomem	*pwr_addr;
+	void __iomem	*tuner_addr;
+	void __iomem	*pcw_addr;
+	const struct mtk_pll_data *data;
+};
+
+static inline struct mtk_clk_pll *to_mtk_clk_pll(struct clk_hw *hw)
+{
+	return container_of(hw, struct mtk_clk_pll, hw);
+}
+
+static int mtk_pll_is_prepared(struct clk_hw *hw)
+{
+	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
+
+	return (readl(pll->base_addr + REG_CON0) & CON0_BASE_EN) != 0;
+}
+
+static unsigned long __mtk_pll_recalc_rate(struct mtk_clk_pll *pll, u32 fin,
+		u32 pcw, int postdiv)
+{
+	int pcwbits = pll->data->pcwbits;
+	int pcwfbits;
+	u64 vco;
+	u8 c = 0;
+
+	/* The fractional part of the PLL divider. */
+	pcwfbits = pcwbits > INTEGER_BITS ? pcwbits - INTEGER_BITS : 0;
+
+	vco = (u64)fin * pcw;
+
+	if (pcwfbits && (vco & GENMASK(pcwfbits - 1, 0)))
+		c = 1;
+
+	vco >>= pcwfbits;
+
+	if (c)
+		vco++;
+
+	return ((unsigned long)vco + postdiv - 1) / postdiv;
+}
+
+static void mtk_pll_set_rate_regs(struct mtk_clk_pll *pll, u32 pcw,
+		int postdiv)
+{
+	u32 con1, pd, val;
+	int pll_en;
+
+	/* set postdiv */
+	pd = readl(pll->pd_addr);
+	pd &= ~(POSTDIV_MASK << pll->data->pd_shift);
+	pd |= (ffs(postdiv) - 1) << pll->data->pd_shift;
+	writel(pd, pll->pd_addr);
+
+	pll_en = readl(pll->base_addr + REG_CON0) & CON0_BASE_EN;
+
+	/* set pcw */
+	val = readl(pll->pcw_addr);
+
+	val &= ~GENMASK(pll->data->pcw_shift + pll->data->pcwbits - 1,
+			pll->data->pcw_shift);
+	val |= pcw << pll->data->pcw_shift;
+	writel(val, pll->pcw_addr);
+
+	con1 = readl(pll->base_addr + REG_CON1);
+
+	if (pll_en)
+		con1 |= CON0_PCW_CHG;
+
+	writel(con1, pll->base_addr + REG_CON1);
+	if (pll->tuner_addr)
+		writel(con1 + 1, pll->tuner_addr);
+
+	if (pll_en)
+		udelay(20);
+}
+
+/*
+ * mtk_pll_calc_values - calculate good values for a given input frequency.
+ * @pll:	The pll
+ * @pcw:	The pcw value (output)
+ * @postdiv:	The post divider (output)
+ * @freq:	The desired target frequency
+ * @fin:	The input frequency
+ *
+ */
+static void mtk_pll_calc_values(struct mtk_clk_pll *pll, u32 *pcw, u32 *postdiv,
+		u32 freq, u32 fin)
+{
+	unsigned long fmin = 1000 * MHZ;
+	u64 _pcw;
+	u32 val;
+
+	if (freq > pll->data->fmax)
+		freq = pll->data->fmax;
+
+	for (val = 0; val < 4; val++) {
+		*postdiv = 1 << val;
+		if (freq * *postdiv >= fmin)
+			break;
+	}
+
+	/* _pcw = freq * postdiv / fin * 2^pcwfbits */
+	_pcw = ((u64)freq << val) << (pll->data->pcwbits - INTEGER_BITS);
+	do_div(_pcw, fin);
+
+	*pcw = (u32)_pcw;
+}
+
+static int mtk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+		unsigned long parent_rate)
+{
+	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
+	u32 pcw = 0;
+	u32 postdiv;
+
+	mtk_pll_calc_values(pll, &pcw, &postdiv, rate, parent_rate);
+	mtk_pll_set_rate_regs(pll, pcw, postdiv);
+
+	return 0;
+}
+
+static unsigned long mtk_pll_recalc_rate(struct clk_hw *hw,
+		unsigned long parent_rate)
+{
+	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
+	u32 postdiv;
+	u32 pcw;
+
+	postdiv = (readl(pll->pd_addr) >> pll->data->pd_shift) & POSTDIV_MASK;
+	postdiv = 1 << postdiv;
+
+	pcw = readl(pll->pcw_addr) >> pll->data->pcw_shift;
+	pcw &= GENMASK(pll->data->pcwbits - 1, 0);
+
+	return __mtk_pll_recalc_rate(pll, parent_rate, pcw, postdiv);
+}
+
+static long mtk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+		unsigned long *prate)
+{
+	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
+	u32 pcw = 0;
+	int postdiv;
+
+	mtk_pll_calc_values(pll, &pcw, &postdiv, rate, *prate);
+
+	return __mtk_pll_recalc_rate(pll, *prate, pcw, postdiv);
+}
+
+static int mtk_pll_prepare(struct clk_hw *hw)
+{
+	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
+	u32 r;
+
+	r = readl(pll->pwr_addr) | CON0_PWR_ON;
+	writel(r, pll->pwr_addr);
+	udelay(1);
+
+	r = readl(pll->pwr_addr) & ~CON0_ISO_EN;
+	writel(r, pll->pwr_addr);
+	udelay(1);
+
+	r = readl(pll->base_addr + REG_CON0);
+	r |= pll->data->en_mask;
+	writel(r, pll->base_addr + REG_CON0);
+
+	if (pll->tuner_addr) {
+		r = readl(pll->tuner_addr) | AUDPLL_TUNER_EN;
+		writel(r, pll->tuner_addr);
+	}
+
+	udelay(20);
+
+	if (pll->data->flags & HAVE_RST_BAR) {
+		r = readl(pll->base_addr + REG_CON0);
+		r |= pll->data->rst_bar_mask;
+		writel(r, pll->base_addr + REG_CON0);
+	}
+
+	return 0;
+}
+
+static void mtk_pll_unprepare(struct clk_hw *hw)
+{
+	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
+	u32 r;
+
+	if (pll->data->flags & HAVE_RST_BAR) {
+		r = readl(pll->base_addr + REG_CON0);
+		r &= ~pll->data->rst_bar_mask;
+		writel(r, pll->base_addr + REG_CON0);
+	}
+
+	if (pll->tuner_addr) {
+		r = readl(pll->tuner_addr) & ~AUDPLL_TUNER_EN;
+		writel(r, pll->tuner_addr);
+	}
+
+	r = readl(pll->base_addr + REG_CON0);
+	r &= ~CON0_BASE_EN;
+	writel(r, pll->base_addr + REG_CON0);
+
+	r = readl(pll->pwr_addr) | CON0_ISO_EN;
+	writel(r, pll->pwr_addr);
+
+	r = readl(pll->pwr_addr) & ~CON0_PWR_ON;
+	writel(r, pll->pwr_addr);
+}
+
+static const struct clk_ops mtk_pll_ops = {
+	.is_prepared	= mtk_pll_is_prepared,
+	.prepare	= mtk_pll_prepare,
+	.unprepare	= mtk_pll_unprepare,
+	.recalc_rate	= mtk_pll_recalc_rate,
+	.round_rate	= mtk_pll_round_rate,
+	.set_rate	= mtk_pll_set_rate,
+};
+
+static struct clk *mtk_clk_register_pll(const struct mtk_pll_data *data,
+		void __iomem *base)
+{
+	struct mtk_clk_pll *pll;
+	struct clk_init_data init;
+	struct clk *clk;
+	const char *parent_name = "clk26m";
+
+	pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+	if (!pll)
+		return ERR_PTR(-ENOMEM);
+
+	pll->base_addr = base + data->reg;
+	pll->pwr_addr = base + data->pwr_reg;
+	pll->pd_addr = base + data->pd_reg;
+	pll->pcw_addr = base + data->pcw_reg;
+	if (data->tuner_reg)
+		pll->tuner_addr = base + data->tuner_reg;
+	pll->hw.init = &init;
+	pll->data = data;
+
+	init.name = data->name;
+	init.ops = &mtk_pll_ops;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	clk = clk_register(NULL, &pll->hw);
+
+	if (IS_ERR(clk))
+		kfree(pll);
+
+	return clk;
+}
+
+void __init mtk_clk_register_plls(struct device_node *node,
+		const struct mtk_pll_data *plls, int num_plls, struct clk_onecell_data *clk_data)
+{
+	void __iomem *base;
+	int r, i;
+	struct clk *clk;
+
+	base = of_iomap(node, 0);
+	if (!base) {
+		pr_err("%s(): ioremap failed\n", __func__);
+		return;
+	}
+
+	for (i = 0; i < num_plls; i++) {
+		const struct mtk_pll_data *pll = &plls[i];
+
+		clk = mtk_clk_register_pll(pll, base);
+
+		if (IS_ERR(clk)) {
+			pr_err("Failed to register clk %s: %ld\n",
+					pll->name, PTR_ERR(clk));
+			continue;
+		}
+
+		clk_data->clks[pll->id] = clk;
+	}
+
+	r = of_clk_add_provider(node, of_clk_src_onecell_get, clk_data);
+	if (r)
+		pr_err("%s(): could not register clock provider: %d\n",
+			__func__, r);
+}