[PATCH V2 1/6] SPEAr: clk: Add VCO-PLL Synthesizer clock
Viresh Kumar
viresh.linux at gmail.com
Thu Apr 19 12:28:16 EDT 2012
All SPEAr SoC's contain PLLs. Their Fout is derived based on following equations
- In normal mode
vco = (2 * M[15:8] * Fin)/N
- In Dithered mode
vco = (2 * M[15:0] * Fin)/(256 * N)
pll_rate = vco/2^p
vco and pll are very closely bound to each other,
"vco needs to program: mode, m & n" and "pll needs to program p",
both share common enable/disable logic and registers.
This patch adds in support for this type of clock.
Signed-off-by: Viresh Kumar <viresh.kumar at st.com>
---
drivers/clk/Makefile | 3 +
drivers/clk/spear/Makefile | 5 +
drivers/clk/spear/clk-vco-pll.c | 346 +++++++++++++++++++++++++++++++++++++++
drivers/clk/spear/clk.h | 76 +++++++++
4 files changed, 430 insertions(+), 0 deletions(-)
create mode 100644 drivers/clk/spear/Makefile
create mode 100644 drivers/clk/spear/clk-vco-pll.c
create mode 100644 drivers/clk/spear/clk.h
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 24aa714..0f5e03d 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -2,3 +2,6 @@
obj-$(CONFIG_CLKDEV_LOOKUP) += clkdev.o
obj-$(CONFIG_COMMON_CLK) += clk.o clk-fixed-rate.o clk-gate.o \
clk-mux.o clk-divider.o clk-fixed-factor.o
+
+# SoCs specific
+obj-$(CONFIG_PLAT_SPEAR) += spear/
diff --git a/drivers/clk/spear/Makefile b/drivers/clk/spear/Makefile
new file mode 100644
index 0000000..f59469f
--- /dev/null
+++ b/drivers/clk/spear/Makefile
@@ -0,0 +1,5 @@
+#
+# SPEAr Clock specific Makefile
+#
+
+obj-y += clk-vco-pll.o
diff --git a/drivers/clk/spear/clk-vco-pll.c b/drivers/clk/spear/clk-vco-pll.c
new file mode 100644
index 0000000..9efa30d
--- /dev/null
+++ b/drivers/clk/spear/clk-vco-pll.c
@@ -0,0 +1,346 @@
+/*
+ * Copyright (C) 2012 ST Microelectronics
+ * Viresh Kumar <viresh.kumar at st.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * VCO-PLL clock implementation
+ */
+
+#define pr_fmt(fmt) "clk-vco-pll: " fmt
+
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include "clk.h"
+
+/*
+ * DOC: VCO-PLL clock
+ *
+ * VCO and PLL rate are derived from following equations:
+ *
+ * In normal mode
+ * vco = (2 * M[15:8] * Fin)/N
+ *
+ * In Dithered mode
+ * vco = (2 * M[15:0] * Fin)/(256 * N)
+ *
+ * pll_rate = pll/2^p
+ *
+ * vco and pll are very closely bound to each other, "vco needs to program:
+ * mode, m & n" and "pll needs to program p", both share common enable/disable
+ * logic.
+ *
+ * clk_register_vco_pll() registers instances of both vco & pll.
+ * CLK_SET_RATE_PARENT flag is forced for pll, as it will always pass its
+ * set_rate to vco. A single rate table exists for both the clocks, which
+ * configures m, n and p.
+ */
+
+/* PLL_CTR register masks */
+#define PLL_MODE_NORMAL 0
+#define PLL_MODE_FRACTION 1
+#define PLL_MODE_DITH_DSM 2
+#define PLL_MODE_DITH_SSM 3
+#define PLL_MODE_MASK 3
+#define PLL_MODE_SHIFT 3
+#define PLL_ENABLE 2
+
+#define PLL_LOCK_SHIFT 0
+#define PLL_LOCK_MASK 1
+
+/* PLL FRQ register masks */
+#define PLL_NORM_FDBK_M_MASK 0xFF
+#define PLL_NORM_FDBK_M_SHIFT 24
+#define PLL_DITH_FDBK_M_MASK 0xFFFF
+#define PLL_DITH_FDBK_M_SHIFT 16
+#define PLL_DIV_P_MASK 0x7
+#define PLL_DIV_P_SHIFT 8
+#define PLL_DIV_N_MASK 0xFF
+#define PLL_DIV_N_SHIFT 0
+
+#define to_clk_vco(_hw) container_of(_hw, struct clk_vco, hw)
+#define to_clk_pll(_hw) container_of(_hw, struct clk_pll, hw)
+
+/* Calculates pll clk rate for specific value of mode, m, n and p */
+static unsigned long pll_calc_rate(struct pll_rate_tbl *rtbl,
+ unsigned long prate, int index, unsigned long *pll_rate)
+{
+ unsigned long rate = prate;
+ unsigned int mode;
+
+ mode = rtbl[index].mode ? 256 : 1;
+ rate = (((2 * rate / 10000) * rtbl[index].m) / (mode * rtbl[index].n));
+
+ if (pll_rate)
+ *pll_rate = (rate / (1 << rtbl[index].p)) * 10000;
+
+ return rate * 10000;
+}
+
+static long clk_pll_round_rate_index(struct clk_hw *hw, unsigned long drate,
+ unsigned long *prate, int *index)
+{
+ struct clk_pll *pll = to_clk_pll(hw);
+ unsigned long prev_rate, vco_prev_rate, rate = 0;
+ unsigned long vco_parent_rate =
+ __clk_get_rate(__clk_get_parent(__clk_get_parent(hw->clk)));
+
+ if (!prate) {
+ pr_err("%s: prate is must for pll clk\n", __func__);
+ return -EINVAL;
+ }
+
+ for (*index = 0; *index < pll->vco->rtbl_cnt; (*index)++) {
+ prev_rate = rate;
+ vco_prev_rate = *prate;
+ *prate = pll_calc_rate(pll->vco->rtbl, vco_parent_rate, *index,
+ &rate);
+ if (drate < rate) {
+ /* previous clock was best */
+ if (*index) {
+ rate = prev_rate;
+ *prate = vco_prev_rate;
+ (*index)--;
+ }
+ break;
+ }
+ }
+
+ return rate;
+}
+
+static long clk_pll_round_rate(struct clk_hw *hw, unsigned long drate,
+ unsigned long *prate)
+{
+ int unused;
+
+ return clk_pll_round_rate_index(hw, drate, prate, &unused);
+}
+
+static unsigned long clk_pll_recalc_rate(struct clk_hw *hw, unsigned long
+ parent_rate)
+{
+ struct clk_pll *pll = to_clk_pll(hw);
+ unsigned long flags = 0;
+ unsigned int p;
+
+ if (pll->vco->lock)
+ spin_lock_irqsave(pll->vco->lock, flags);
+
+ p = readl_relaxed(pll->vco->cfg_reg);
+
+ if (pll->vco->lock)
+ spin_unlock_irqrestore(pll->vco->lock, flags);
+
+ p = (p >> PLL_DIV_P_SHIFT) & PLL_DIV_P_MASK;
+
+ return parent_rate / (1 << p);
+}
+
+static int clk_pll_set_rate(struct clk_hw *hw, unsigned long drate)
+{
+ struct clk_pll *pll = to_clk_pll(hw);
+ struct pll_rate_tbl *rtbl = pll->vco->rtbl;
+ unsigned long flags = 0, val;
+ int i;
+
+ clk_pll_round_rate_index(hw, drate, NULL, &i);
+
+ if (pll->vco->lock)
+ spin_lock_irqsave(pll->vco->lock, flags);
+
+ val = readl_relaxed(pll->vco->cfg_reg);
+ val &= ~(PLL_DIV_P_MASK << PLL_DIV_P_SHIFT);
+ val |= (rtbl[i].p & PLL_DIV_P_MASK) << PLL_DIV_P_SHIFT;
+ writel_relaxed(val, pll->vco->cfg_reg);
+
+ if (pll->vco->lock)
+ spin_unlock_irqrestore(pll->vco->lock, flags);
+
+ return 0;
+}
+
+static struct clk_ops clk_pll_ops = {
+ .recalc_rate = clk_pll_recalc_rate,
+ .round_rate = clk_pll_round_rate,
+ .set_rate = clk_pll_set_rate,
+};
+
+static inline unsigned long vco_calc_rate(struct clk_hw *hw,
+ unsigned long prate, int index)
+{
+ struct clk_vco *vco = to_clk_vco(hw);
+
+ return pll_calc_rate(vco->rtbl, prate, index, NULL);
+}
+
+static long clk_vco_round_rate(struct clk_hw *hw, unsigned long drate,
+ unsigned long *prate)
+{
+ struct clk_vco *vco = to_clk_vco(hw);
+ int unused;
+
+ return clk_round_rate_index(hw, drate, vco_calc_rate, vco->rtbl_cnt,
+ &unused);
+}
+
+static unsigned long clk_vco_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_vco *vco = to_clk_vco(hw);
+ unsigned long flags = 0;
+ unsigned int num = 2, den = 0, val, mode = 0;
+
+ if (vco->lock)
+ spin_lock_irqsave(vco->lock, flags);
+
+ mode = (readl_relaxed(vco->mode_reg) >> PLL_MODE_SHIFT) & PLL_MODE_MASK;
+
+ val = readl_relaxed(vco->cfg_reg);
+
+ if (vco->lock)
+ spin_unlock_irqrestore(vco->lock, flags);
+
+ den = (val >> PLL_DIV_N_SHIFT) & PLL_DIV_N_MASK;
+
+ /* calculate numerator & denominator */
+ if (!mode) {
+ /* Normal mode */
+ num *= (val >> PLL_NORM_FDBK_M_SHIFT) & PLL_NORM_FDBK_M_MASK;
+ } else {
+ /* Dithered mode */
+ num *= (val >> PLL_DITH_FDBK_M_SHIFT) & PLL_DITH_FDBK_M_MASK;
+ den *= 256;
+ }
+
+ if (!den) {
+ WARN(1, "%s: denominator can't be zero\n", __func__);
+ return 0;
+ }
+
+ return (((parent_rate / 10000) * num) / den) * 10000;
+}
+
+/* Configures new clock rate of vco */
+static int clk_vco_set_rate(struct clk_hw *hw, unsigned long drate)
+{
+ struct clk_vco *vco = to_clk_vco(hw);
+ struct pll_rate_tbl *rtbl = vco->rtbl;
+ unsigned long flags = 0, val;
+ int i;
+
+ clk_round_rate_index(hw, drate, vco_calc_rate, vco->rtbl_cnt, &i);
+
+ if (vco->lock)
+ spin_lock_irqsave(vco->lock, flags);
+
+ val = readl_relaxed(vco->mode_reg);
+ val &= ~(PLL_MODE_MASK << PLL_MODE_SHIFT);
+ val |= (rtbl[i].mode & PLL_MODE_MASK) << PLL_MODE_SHIFT;
+ writel_relaxed(val, vco->mode_reg);
+
+ val = readl_relaxed(vco->cfg_reg);
+ val &= ~(PLL_DIV_N_MASK << PLL_DIV_N_SHIFT);
+ val |= (rtbl[i].n & PLL_DIV_N_MASK) << PLL_DIV_N_SHIFT;
+
+ val &= ~(PLL_DITH_FDBK_M_MASK << PLL_DITH_FDBK_M_SHIFT);
+ if (rtbl[i].mode)
+ val |= (rtbl[i].m & PLL_DITH_FDBK_M_MASK) <<
+ PLL_DITH_FDBK_M_SHIFT;
+ else
+ val |= (rtbl[i].m & PLL_NORM_FDBK_M_MASK) <<
+ PLL_NORM_FDBK_M_SHIFT;
+
+ writel_relaxed(val, vco->cfg_reg);
+
+ if (vco->lock)
+ spin_unlock_irqrestore(vco->lock, flags);
+
+ return 0;
+}
+
+static struct clk_ops clk_vco_ops = {
+ .recalc_rate = clk_vco_recalc_rate,
+ .round_rate = clk_vco_round_rate,
+ .set_rate = clk_vco_set_rate,
+};
+
+struct clk *clk_register_vco_pll(const char *vco_name, const char *pll_name,
+ const char *vco_gate_name, const char *parent_name,
+ unsigned long flags, void __iomem *mode_reg, void __iomem
+ *cfg_reg, struct pll_rate_tbl *rtbl, u8 rtbl_cnt,
+ spinlock_t *lock, struct clk **pll_clk,
+ struct clk **vco_gate_clk)
+{
+ struct clk_vco *vco;
+ struct clk_pll *pll;
+ struct clk *vco_clk, *tpll_clk, *tvco_gate_clk;
+ const char **vco_parent_name;
+
+ if (!vco_name || !pll_name || !parent_name || !mode_reg || !cfg_reg ||
+ !rtbl || !rtbl_cnt) {
+ pr_err("Invalid arguments passed");
+ return ERR_PTR(-EINVAL);
+ }
+
+ vco = kzalloc(sizeof(*vco), GFP_KERNEL);
+ if (!vco) {
+ pr_err("could not allocate vco clk\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+ if (!pll) {
+ pr_err("could not allocate pll clk\n");
+ goto free_vco;
+ }
+
+ /* struct clk_vco assignments */
+ vco->mode_reg = mode_reg;
+ vco->cfg_reg = cfg_reg;
+ vco->rtbl = rtbl;
+ vco->rtbl_cnt = rtbl_cnt;
+ vco->lock = lock;
+ pll->vco = vco;
+
+ if (vco_gate_name) {
+ tvco_gate_clk = clk_register_gate(NULL, vco_gate_name,
+ parent_name, 0, mode_reg, PLL_ENABLE, 0, lock);
+ if (IS_ERR_OR_NULL(tvco_gate_clk))
+ goto free_pll;
+
+ if (vco_gate_clk)
+ *vco_gate_clk = tvco_gate_clk;
+ vco_parent_name = &vco_gate_name;
+ } else {
+ vco_parent_name = &parent_name;
+ }
+
+ vco_clk = clk_register(NULL, vco_name, &clk_vco_ops, &vco->hw,
+ vco_parent_name, 1, flags);
+ if (IS_ERR_OR_NULL(vco_clk))
+ goto free_pll;
+
+ tpll_clk = clk_register(NULL, pll_name, &clk_pll_ops, &pll->hw,
+ &vco_name, 1, CLK_SET_RATE_PARENT);
+ if (IS_ERR_OR_NULL(tpll_clk))
+ goto free_pll;
+
+ if (pll_clk)
+ *pll_clk = tpll_clk;
+
+ return vco_clk;
+
+free_pll:
+ kfree(pll);
+free_vco:
+ kfree(vco);
+
+ pr_err("Failed to register vco pll clock\n");
+
+ return ERR_PTR(-ENOMEM);
+}
diff --git a/drivers/clk/spear/clk.h b/drivers/clk/spear/clk.h
new file mode 100644
index 0000000..a66024e
--- /dev/null
+++ b/drivers/clk/spear/clk.h
@@ -0,0 +1,76 @@
+/*
+ * Clock framework definitions for SPEAr platform
+ *
+ * Copyright (C) 2012 ST Microelectronics
+ * Viresh Kumar <viresh.kumar at st.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#ifndef __PLAT_CLOCK_H
+#define __PLAT_CLOCK_H
+
+#include <linux/clk-provider.h>
+#include <linux/spinlock_types.h>
+#include <linux/types.h>
+
+/* VCO-PLL clk */
+struct pll_rate_tbl {
+ u8 mode;
+ u16 m;
+ u8 n;
+ u8 p;
+};
+
+struct clk_vco {
+ struct clk_hw hw;
+ void __iomem *mode_reg;
+ void __iomem *cfg_reg;
+ struct pll_rate_tbl *rtbl;
+ u8 rtbl_cnt;
+ spinlock_t *lock;
+};
+
+struct clk_pll {
+ struct clk_hw hw;
+ struct clk_vco *vco;
+ const char *parent[1];
+ spinlock_t *lock;
+};
+
+typedef unsigned long (*clk_calc_rate)(struct clk_hw *hw, unsigned long prate,
+ int index);
+
+/* clk register routines */
+struct clk *clk_register_vco_pll(const char *vco_name, const char *pll_name,
+ const char *vco_gate_name, const char *parent_name,
+ unsigned long flags, void __iomem *mode_reg, void __iomem
+ *cfg_reg, struct pll_rate_tbl *rtbl, u8 rtbl_cnt,
+ spinlock_t *lock, struct clk **pll_clk,
+ struct clk **vco_gate_clk);
+
+static inline long clk_round_rate_index(struct clk_hw *hw, unsigned long drate,
+ clk_calc_rate calc_rate, u8 rtbl_cnt, int *index)
+{
+ unsigned long prev_rate, rate = 0;
+ unsigned long parent_rate = __clk_get_rate(__clk_get_parent(hw->clk));
+
+ for (*index = 0; *index < rtbl_cnt; (*index)++) {
+ prev_rate = rate;
+ rate = calc_rate(hw, parent_rate, *index);
+ if (drate < rate) {
+ /* previous clock was best */
+ if (*index) {
+ rate = prev_rate;
+ (*index)--;
+ }
+ break;
+ }
+ }
+
+ return rate;
+}
+
+#endif /* __PLAT_CLOCK_H */
--
1.7.9
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