[PATCH v3 05/13] clk: qcom: Add support for High-Frequency PLLs (HFPLLs)

Stephen Boyd
2015-03-21T06:46:48Z

HFPLLs are the main frequency source for Krait CPU clocks. Add
support for changing the rate of these PLLs.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---

I'd really like to get rid of __clk_hfpll_init_once() if possible...

drivers/clk/qcom/Makefile | 1 +
drivers/clk/qcom/clk-hfpll.c | 253 +++++++++++++++++++++++++++++++++++++++++++
drivers/clk/qcom/clk-hfpll.h | 54 +++++++++
3 files changed, 308 insertions(+)
create mode 100644 drivers/clk/qcom/clk-hfpll.c
create mode 100644 drivers/clk/qcom/clk-hfpll.h

diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
index 617826469595..953f792d2133 100644
--- a/drivers/clk/qcom/Makefile
+++ b/drivers/clk/qcom/Makefile
@@ -8,6 +8,7 @@ clk-qcom-y += clk-rcg2.o
clk-qcom-y += clk-branch.o
clk-qcom-y += clk-regmap-divider.o
clk-qcom-y += clk-regmap-mux.o
+clk-qcom-y += clk-hfpll.o
clk-qcom-y += reset.o

obj-$(CONFIG_APQ_GCC_8084) += gcc-apq8084.o
diff --git a/drivers/clk/qcom/clk-hfpll.c b/drivers/clk/qcom/clk-hfpll.c
new file mode 100644
index 000000000000..367eb95f1477
--- /dev/null
+++ b/drivers/clk/qcom/clk-hfpll.c
@@ -0,0 +1,253 @@
+/*
+ * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only 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/kernel.h>
+#include <linux/export.h>
+#include <linux/regmap.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/clk-provider.h>
+#include <linux/spinlock.h>
+
+#include "clk-regmap.h"
+#include "clk-hfpll.h"
+
+#define PLL_OUTCTRL BIT(0)
+#define PLL_BYPASSNL BIT(1)
+#define PLL_RESET_N BIT(2)
+
+/* Initialize a HFPLL at a given rate and enable it. */
+static void __clk_hfpll_init_once(struct clk_hw *hw)
+{
+ struct clk_hfpll *h = to_clk_hfpll(hw);
+ struct hfpll_data const *hd = h->d;
+ struct regmap *regmap = h->clkr.regmap;
+
+ if (likely(h->init_done))
+ return;
+
+ /* Configure PLL parameters for integer mode. */
+ if (hd->config_val)
+ regmap_write(regmap, hd->config_reg, hd->config_val);
+ regmap_write(regmap, hd->m_reg, 0);
+ regmap_write(regmap, hd->n_reg, 1);
+
+ if (hd->user_reg) {
+ u32 regval = hd->user_val;
+ unsigned long rate;
+
+ rate = __clk_get_rate(hw->clk);
+
+ /* Pick the right VCO. */
+ if (hd->user_vco_mask && rate > hd->low_vco_max_rate)
+ regval |= hd->user_vco_mask;
+ regmap_write(regmap, hd->user_reg, regval);
+ }
+
+ if (hd->droop_reg)
+ regmap_write(regmap, hd->droop_reg, hd->droop_val);
+
+ h->init_done = true;
+}
+
+static void __clk_hfpll_enable(struct clk_hw *hw)
+{
+ struct clk_hfpll *h = to_clk_hfpll(hw);
+ struct hfpll_data const *hd = h->d;
+ struct regmap *regmap = h->clkr.regmap;
+ u32 val;
+
+ __clk_hfpll_init_once(hw);
+
+ /* Disable PLL bypass mode. */
+ regmap_update_bits(regmap, hd->mode_reg, PLL_BYPASSNL, PLL_BYPASSNL);
+
+ /*
+ * H/W requires a 5us delay between disabling the bypass and
+ * de-asserting the reset. Delay 10us just to be safe.
+ */
+ udelay(10);
+
+ /* De-assert active-low PLL reset. */
+ regmap_update_bits(regmap, hd->mode_reg, PLL_RESET_N, PLL_RESET_N);
+
+ /* Wait for PLL to lock. */
+ if (hd->status_reg) {
+ do {
+ regmap_read(regmap, hd->status_reg, &val);
+ } while (!(val & BIT(hd->lock_bit)));
+ } else {
+ udelay(60);
+ }
+
+ /* Enable PLL output. */
+ regmap_update_bits(regmap, hd->mode_reg, PLL_OUTCTRL, PLL_OUTCTRL);
+}
+
+/* Enable an already-configured HFPLL. */
+static int clk_hfpll_enable(struct clk_hw *hw)
+{
+ unsigned long flags;
+ struct clk_hfpll *h = to_clk_hfpll(hw);
+ struct hfpll_data const *hd = h->d;
+ struct regmap *regmap = h->clkr.regmap;
+ u32 mode;
+
+ spin_lock_irqsave(&h->lock, flags);
+ regmap_read(regmap, hd->mode_reg, &mode);
+ if (!(mode & (PLL_BYPASSNL | PLL_RESET_N | PLL_OUTCTRL)))
+ __clk_hfpll_enable(hw);
+ spin_unlock_irqrestore(&h->lock, flags);
+
+ return 0;
+}
+
+static void __clk_hfpll_disable(struct clk_hfpll *h)
+{
+ struct hfpll_data const *hd = h->d;
+ struct regmap *regmap = h->clkr.regmap;
+
+ /*
+ * Disable the PLL output, disable test mode, enable the bypass mode,
+ * and assert the reset.
+ */
+ regmap_update_bits(regmap, hd->mode_reg,
+ PLL_BYPASSNL | PLL_RESET_N | PLL_OUTCTRL, 0);
+}
+
+static void clk_hfpll_disable(struct clk_hw *hw)
+{
+ struct clk_hfpll *h = to_clk_hfpll(hw);
+ unsigned long flags;
+
+ spin_lock_irqsave(&h->lock, flags);
+ __clk_hfpll_disable(h);
+ spin_unlock_irqrestore(&h->lock, flags);
+}
+
+static long clk_hfpll_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct clk_hfpll *h = to_clk_hfpll(hw);
+ struct hfpll_data const *hd = h->d;
+ unsigned long rrate;
+
+ rate = clamp(rate, hd->min_rate, hd->max_rate);
+
+ rrate = DIV_ROUND_UP(rate, *parent_rate) * *parent_rate;
+ if (rrate > hd->max_rate)
+ rrate -= *parent_rate;
+
+ return rrate;
+}
+
+/*
+ * For optimization reasons, assumes no downstream clocks are actively using
+ * it.
+ */
+static int clk_hfpll_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_hfpll *h = to_clk_hfpll(hw);
+ struct hfpll_data const *hd = h->d;
+ struct regmap *regmap = h->clkr.regmap;
+ unsigned long flags;
+ u32 l_val, val;
+ bool enabled;
+
+ l_val = rate / parent_rate;
+
+ spin_lock_irqsave(&h->lock, flags);
+
+ enabled = __clk_is_enabled(hw->clk);
+ if (enabled)
+ __clk_hfpll_disable(h);
+
+ /* Pick the right VCO. */
+ if (hd->user_reg && hd->user_vco_mask) {
+ regmap_read(regmap, hd->user_reg, &val);
+ if (rate <= hd->low_vco_max_rate)
+ val &= ~hd->user_vco_mask;
+ else
+ val |= hd->user_vco_mask;
+ regmap_write(regmap, hd->user_reg, val);
+ }
+
+ regmap_write(regmap, hd->l_reg, l_val);
+
+ if (enabled)
+ __clk_hfpll_enable(hw);
+
+ spin_unlock_irqrestore(&h->lock, flags);
+
+ return 0;
+}
+
+static unsigned long clk_hfpll_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_hfpll *h = to_clk_hfpll(hw);
+ struct hfpll_data const *hd = h->d;
+ struct regmap *regmap = h->clkr.regmap;
+ u32 l_val;
+
+ regmap_read(regmap, hd->l_reg, &l_val);
+
+ return l_val * parent_rate;
+}
+
+static void clk_hfpll_init(struct clk_hw *hw)
+{
+ struct clk_hfpll *h = to_clk_hfpll(hw);
+ struct hfpll_data const *hd = h->d;
+ struct regmap *regmap = h->clkr.regmap;
+ u32 mode, status;
+
+ regmap_read(regmap, hd->mode_reg, &mode);
+ if (mode != (PLL_BYPASSNL | PLL_RESET_N | PLL_OUTCTRL)) {
+ __clk_hfpll_init_once(hw);
+ return;
+ }
+
+ if (hd->status_reg) {
+ regmap_read(regmap, hd->status_reg, &status);
+ if (!(status & BIT(hd->lock_bit))) {
+ WARN(1, "HFPLL %s is ON, but not locked!\n",
+ __clk_get_name(hw->clk));
+ clk_hfpll_disable(hw);
+ __clk_hfpll_init_once(hw);
+ }
+ }
+}
+
+static int hfpll_is_enabled(struct clk_hw *hw)
+{
+ struct clk_hfpll *h = to_clk_hfpll(hw);
+ struct hfpll_data const *hd = h->d;
+ struct regmap *regmap = h->clkr.regmap;
+ u32 mode;
+
+ regmap_read(regmap, hd->mode_reg, &mode);
+ mode &= 0x7;
+ return mode == (PLL_BYPASSNL | PLL_RESET_N | PLL_OUTCTRL);
+}
+
+const struct clk_ops clk_ops_hfpll = {
+ .enable = clk_hfpll_enable,
+ .disable = clk_hfpll_disable,
+ .is_enabled = hfpll_is_enabled,
+ .round_rate = clk_hfpll_round_rate,
+ .set_rate = clk_hfpll_set_rate,
+ .recalc_rate = clk_hfpll_recalc_rate,
+ .init = clk_hfpll_init,
+};
+EXPORT_SYMBOL_GPL(clk_ops_hfpll);
diff --git a/drivers/clk/qcom/clk-hfpll.h b/drivers/clk/qcom/clk-hfpll.h
new file mode 100644
index 000000000000..48c18d664f4e
--- /dev/null
+++ b/drivers/clk/qcom/clk-hfpll.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2013-2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only 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.
+ */
+#ifndef __QCOM_CLK_HFPLL_H__
+#define __QCOM_CLK_HFPLL_H__
+
+#include <linux/clk-provider.h>
+#include <linux/spinlock.h>
+#include "clk-regmap.h"
+
+struct hfpll_data {
+ u32 mode_reg;
+ u32 l_reg;
+ u32 m_reg;
+ u32 n_reg;
+ u32 user_reg;
+ u32 droop_reg;
+ u32 config_reg;
+ u32 status_reg;
+ u8 lock_bit;
+
+ u32 droop_val;
+ u32 config_val;
+ u32 user_val;
+ u32 user_vco_mask;
+ unsigned long low_vco_max_rate;
+
+ unsigned long min_rate;
+ unsigned long max_rate;
+};
+
+struct clk_hfpll {
+ struct hfpll_data const *d;
+ int init_done;
+
+ struct clk_regmap clkr;
+ spinlock_t lock;
+};
+
+#define to_clk_hfpll(_hw) \
+ container_of(to_clk_regmap(_hw), struct clk_hfpll, clkr)
+
+extern const struct clk_ops clk_ops_hfpll;
+
+#endif