clk: qcom: Add Alpha PLL support

Add support for configuring rates of, enabling, and disabling
Alpha PLLs. This is sufficient for the types of PLLs found in
the global and multimedia clock controllers.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/qcom/Makefile

@@ -2,6 +2,7 @@ obj-$(CONFIG_COMMON_CLK_QCOM) += clk-qcom.o
 
 clk-qcom-y += common.o
 clk-qcom-y += clk-regmap.o
+clk-qcom-y += clk-alpha-pll.o
 clk-qcom-y += clk-pll.o
 clk-qcom-y += clk-rcg.o
 clk-qcom-y += clk-rcg2.o

drivers/clk/qcom/clk-alpha-pll.c

+/*
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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/kernel.h>
+#include <linux/export.h>
+#include <linux/clk-provider.h>
+#include <linux/regmap.h>
+#include <linux/delay.h>
+
+#include "clk-alpha-pll.h"
+
+#define PLL_MODE		0x00
+# define PLL_OUTCTRL		BIT(0)
+# define PLL_BYPASSNL		BIT(1)
+# define PLL_RESET_N		BIT(2)
+# define PLL_LOCK_COUNT_SHIFT	8
+# define PLL_LOCK_COUNT_MASK	0x3f
+# define PLL_BIAS_COUNT_SHIFT	14
+# define PLL_BIAS_COUNT_MASK	0x3f
+# define PLL_VOTE_FSM_ENA	BIT(20)
+# define PLL_VOTE_FSM_RESET	BIT(21)
+# define PLL_ACTIVE_FLAG	BIT(30)
+# define PLL_LOCK_DET		BIT(31)
+
+#define PLL_L_VAL		0x04
+#define PLL_ALPHA_VAL		0x08
+#define PLL_ALPHA_VAL_U		0x0c
+
+#define PLL_USER_CTL		0x10
+# define PLL_POST_DIV_SHIFT	8
+# define PLL_POST_DIV_MASK	0xf
+# define PLL_ALPHA_EN		BIT(24)
+# define PLL_VCO_SHIFT		20
+# define PLL_VCO_MASK		0x3
+
+#define PLL_USER_CTL_U		0x14
+
+#define PLL_CONFIG_CTL		0x18
+#define PLL_TEST_CTL		0x1c
+#define PLL_TEST_CTL_U		0x20
+#define PLL_STATUS		0x24
+
+/*
+ * Even though 40 bits are present, use only 32 for ease of calculation.
+ */
+#define ALPHA_REG_BITWIDTH	40
+#define ALPHA_BITWIDTH		32
+
+#define to_clk_alpha_pll(_hw) container_of(to_clk_regmap(_hw), \
+					   struct clk_alpha_pll, clkr)
+
+#define to_clk_alpha_pll_postdiv(_hw) container_of(to_clk_regmap(_hw), \
+					   struct clk_alpha_pll_postdiv, clkr)
+
+static int wait_for_pll(struct clk_alpha_pll *pll)
+{
+	u32 val, mask, off;
+	int count;
+	int ret;
+	const char *name = clk_hw_get_name(&pll->clkr.hw);
+
+	off = pll->offset;
+	ret = regmap_read(pll->clkr.regmap, off + PLL_MODE, &val);
+	if (ret)
+		return ret;
+
+	if (val & PLL_VOTE_FSM_ENA)
+		mask = PLL_ACTIVE_FLAG;
+	else
+		mask = PLL_LOCK_DET;
+
+	/* Wait for pll to enable. */
+	for (count = 100; count > 0; count--) {
+		ret = regmap_read(pll->clkr.regmap, off + PLL_MODE, &val);
+		if (ret)
+			return ret;
+		if ((val & mask) == mask)
+			return 0;
+
+		udelay(1);
+	}
+
+	WARN(1, "%s didn't enable after voting for it!\n", name);
+	return -ETIMEDOUT;
+}
+
+static int clk_alpha_pll_enable(struct clk_hw *hw)
+{
+	int ret;
+	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
+	u32 val, mask, off;
+
+	off = pll->offset;
+
+	mask = PLL_OUTCTRL | PLL_RESET_N | PLL_BYPASSNL;
+	ret = regmap_read(pll->clkr.regmap, off + PLL_MODE, &val);
+	if (ret)
+		return ret;
+
+	/* If in FSM mode, just vote for it */
+	if (val & PLL_VOTE_FSM_ENA) {
+		ret = clk_enable_regmap(hw);
+		if (ret)
+			return ret;
+		return wait_for_pll(pll);
+	}
+
+	/* Skip if already enabled */
+	if ((val & mask) == mask)
+		return 0;
+
+	ret = regmap_update_bits(pll->clkr.regmap, off + PLL_MODE,
+				 PLL_BYPASSNL, PLL_BYPASSNL);
+	if (ret)
+		return ret;
+
+	/*
+	 * H/W requires a 5us delay between disabling the bypass and
+	 * de-asserting the reset.
+	 */
+	mb();
+	udelay(5);
+
+	ret = regmap_update_bits(pll->clkr.regmap, off + PLL_MODE,
+				 PLL_RESET_N, PLL_RESET_N);
+	if (ret)
+		return ret;
+
+	ret = wait_for_pll(pll);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(pll->clkr.regmap, off + PLL_MODE,
+				 PLL_OUTCTRL, PLL_OUTCTRL);
+
+	/* Ensure that the write above goes through before returning. */
+	mb();
+	return ret;
+}
+
+static void clk_alpha_pll_disable(struct clk_hw *hw)
+{
+	int ret;
+	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
+	u32 val, mask, off;
+
+	off = pll->offset;
+
+	ret = regmap_read(pll->clkr.regmap, off + PLL_MODE, &val);
+	if (ret)
+		return;
+
+	/* If in FSM mode, just unvote it */
+	if (val & PLL_VOTE_FSM_ENA) {
+		clk_disable_regmap(hw);
+		return;
+	}
+
+	mask = PLL_OUTCTRL;
+	regmap_update_bits(pll->clkr.regmap, off + PLL_MODE, mask, 0);
+
+	/* Delay of 2 output clock ticks required until output is disabled */
+	mb();
+	udelay(1);
+
+	mask = PLL_RESET_N | PLL_BYPASSNL;
+	regmap_update_bits(pll->clkr.regmap, off + PLL_MODE, mask, 0);
+}
+
+static unsigned long alpha_pll_calc_rate(u64 prate, u32 l, u32 a)
+{
+	return (prate * l) + ((prate * a) >> ALPHA_BITWIDTH);
+}
+
+static unsigned long
+alpha_pll_round_rate(unsigned long rate, unsigned long prate, u32 *l, u64 *a)
+{
+	u64 remainder;
+	u64 quotient;
+
+	quotient = rate;
+	remainder = do_div(quotient, prate);
+	*l = quotient;
+
+	if (!remainder) {
+		*a = 0;
+		return rate;
+	}
+
+	/* Upper ALPHA_BITWIDTH bits of Alpha */
+	quotient = remainder << ALPHA_BITWIDTH;
+	remainder = do_div(quotient, prate);
+
+	if (remainder)
+		quotient++;
+
+	*a = quotient;
+	return alpha_pll_calc_rate(prate, *l, *a);
+}
+
+static const struct pll_vco *
+alpha_pll_find_vco(const struct clk_alpha_pll *pll, unsigned long rate)
+{
+	const struct pll_vco *v = pll->vco_table;
+	const struct pll_vco *end = v + pll->num_vco;
+
+	for (; v < end; v++)
+		if (rate >= v->min_freq && rate <= v->max_freq)
+			return v;
+
+	return NULL;
+}
+
+static unsigned long
+clk_alpha_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+	u32 l, low, high, ctl;
+	u64 a = 0, prate = parent_rate;
+	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
+	u32 off = pll->offset;
+
+	regmap_read(pll->clkr.regmap, off + PLL_L_VAL, &l);
+
+	regmap_read(pll->clkr.regmap, off + PLL_USER_CTL, &ctl);
+	if (ctl & PLL_ALPHA_EN) {
+		regmap_read(pll->clkr.regmap, off + PLL_ALPHA_VAL, &low);
+		regmap_read(pll->clkr.regmap, off + PLL_ALPHA_VAL_U, &high);
+		a = (u64)high << 32 | low;
+		a >>= ALPHA_REG_BITWIDTH - ALPHA_BITWIDTH;
+	}
+
+	return alpha_pll_calc_rate(prate, l, a);
+}
+
+static int clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
+				  unsigned long prate)
+{
+	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
+	const struct pll_vco *vco;
+	u32 l, off = pll->offset;
+	u64 a;
+
+	rate = alpha_pll_round_rate(rate, prate, &l, &a);
+	vco = alpha_pll_find_vco(pll, rate);
+	if (!vco) {
+		pr_err("alpha pll not in a valid vco range\n");
+		return -EINVAL;
+	}
+
+	a <<= (ALPHA_REG_BITWIDTH - ALPHA_BITWIDTH);
+
+	regmap_write(pll->clkr.regmap, off + PLL_L_VAL, l);
+	regmap_write(pll->clkr.regmap, off + PLL_ALPHA_VAL, a);
+	regmap_write(pll->clkr.regmap, off + PLL_ALPHA_VAL_U, a >> 32);
+
+	regmap_update_bits(pll->clkr.regmap, off + PLL_USER_CTL,
+			   PLL_VCO_MASK << PLL_VCO_SHIFT,
+			   vco->val << PLL_VCO_SHIFT);
+
+	regmap_update_bits(pll->clkr.regmap, off + PLL_USER_CTL, PLL_ALPHA_EN,
+			   PLL_ALPHA_EN);
+
+	return 0;
+}
+
+static long clk_alpha_pll_round_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long *prate)
+{
+	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
+	u32 l;
+	u64 a;
+	unsigned long min_freq, max_freq;
+
+	rate = alpha_pll_round_rate(rate, *prate, &l, &a);
+	if (alpha_pll_find_vco(pll, rate))
+		return rate;
+
+	min_freq = pll->vco_table[0].min_freq;
+	max_freq = pll->vco_table[pll->num_vco - 1].max_freq;
+
+	return clamp(rate, min_freq, max_freq);
+}
+
+const struct clk_ops clk_alpha_pll_ops = {
+	.enable = clk_alpha_pll_enable,
+	.disable = clk_alpha_pll_disable,
+	.recalc_rate = clk_alpha_pll_recalc_rate,
+	.round_rate = clk_alpha_pll_round_rate,
+	.set_rate = clk_alpha_pll_set_rate,
+};
+EXPORT_SYMBOL_GPL(clk_alpha_pll_ops);
+
+static unsigned long
+clk_alpha_pll_postdiv_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+	struct clk_alpha_pll_postdiv *pll = to_clk_alpha_pll_postdiv(hw);
+	u32 ctl;
+
+	regmap_read(pll->clkr.regmap, pll->offset + PLL_USER_CTL, &ctl);
+
+	ctl >>= PLL_POST_DIV_SHIFT;
+	ctl &= PLL_POST_DIV_MASK;
+
+	return parent_rate >> fls(ctl);
+}
+
+static const struct clk_div_table clk_alpha_div_table[] = {
+	{ 0x0, 1 },
+	{ 0x1, 2 },
+	{ 0x3, 4 },
+	{ 0x7, 8 },
+	{ 0xf, 16 },
+	{ }
+};
+
+static long
+clk_alpha_pll_postdiv_round_rate(struct clk_hw *hw, unsigned long rate,
+				 unsigned long *prate)
+{
+	struct clk_alpha_pll_postdiv *pll = to_clk_alpha_pll_postdiv(hw);
+
+	return divider_round_rate(hw, rate, prate, clk_alpha_div_table,
+				  pll->width, CLK_DIVIDER_POWER_OF_TWO);
+}
+
+static int clk_alpha_pll_postdiv_set_rate(struct clk_hw *hw, unsigned long rate,
+					  unsigned long parent_rate)
+{
+	struct clk_alpha_pll_postdiv *pll = to_clk_alpha_pll_postdiv(hw);
+	int div;
+
+	/* 16 -> 0xf, 8 -> 0x7, 4 -> 0x3, 2 -> 0x1, 1 -> 0x0 */
+	div = DIV_ROUND_UP_ULL((u64)parent_rate, rate) - 1;
+
+	return regmap_update_bits(pll->clkr.regmap, pll->offset + PLL_USER_CTL,
+				  PLL_POST_DIV_MASK << PLL_POST_DIV_SHIFT,
+				  div << PLL_POST_DIV_SHIFT);
+}
+
+const struct clk_ops clk_alpha_pll_postdiv_ops = {
+	.recalc_rate = clk_alpha_pll_postdiv_recalc_rate,
+	.round_rate = clk_alpha_pll_postdiv_round_rate,
+	.set_rate = clk_alpha_pll_postdiv_set_rate,
+};
+EXPORT_SYMBOL_GPL(clk_alpha_pll_postdiv_ops);

drivers/clk/qcom/clk-alpha-pll.h

+/*
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#ifndef __QCOM_CLK_ALPHA_PLL_H__
+#define __QCOM_CLK_ALPHA_PLL_H__
+
+#include <linux/clk-provider.h>
+#include "clk-regmap.h"
+
+struct pll_vco {
+	unsigned long min_freq;
+	unsigned long max_freq;
+	u32 val;
+};
+
+/**
+ * struct clk_alpha_pll - phase locked loop (PLL)
+ * @offset: base address of registers
+ * @vco_table: array of VCO settings
+ * @clkr: regmap clock handle
+ */
+struct clk_alpha_pll {
+	u32 offset;
+
+	const struct pll_vco *vco_table;
+	size_t num_vco;
+
+	struct clk_regmap clkr;
+};
+
+/**
+ * struct clk_alpha_pll_postdiv - phase locked loop (PLL) post-divider
+ * @offset: base address of registers
+ * @width: width of post-divider
+ * @clkr: regmap clock handle
+ */
+struct clk_alpha_pll_postdiv {
+	u32 offset;
+	u8 width;
+
+	struct clk_regmap clkr;
+};
+
+extern const struct clk_ops clk_alpha_pll_ops;
+extern const struct clk_ops clk_alpha_pll_postdiv_ops;
+
+#endif