[PATCH V5 4/5] clk: imx: support fracn gppll

Peng Fan (OSS)
2022-02-25T01:41:14Z

From: Peng Fan <peng.fan@nxp.com>

This PLL module is a Fractional-N synthesizer,
supporting 30-bit numerator and denominator. Numerator is a signed
number. It has feature to adjust fractional portion of feedback
divider dynamically. This fracn gppll is used in i.MX93.

Reviewed-by: Abel Vesa <abel.vesa@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
drivers/clk/imx/Makefile | 1 +
drivers/clk/imx/clk-fracn-gppll.c | 324 ++++++++++++++++++++++++++++++
drivers/clk/imx/clk.h | 21 ++
3 files changed, 346 insertions(+)
create mode 100644 drivers/clk/imx/clk-fracn-gppll.c

diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
index 36c04922d789..60c8a4bb7574 100644
--- a/drivers/clk/imx/Makefile
+++ b/drivers/clk/imx/Makefile
@@ -5,6 +5,7 @@ mxc-clk-objs += clk-busy.o
mxc-clk-objs += clk-composite-7ulp.o
mxc-clk-objs += clk-composite-8m.o
mxc-clk-objs += clk-composite-93.o
+mxc-clk-objs += clk-fracn-gppll.o
mxc-clk-objs += clk-cpu.o
mxc-clk-objs += clk-divider-gate.o
mxc-clk-objs += clk-fixup-div.o
diff --git a/drivers/clk/imx/clk-fracn-gppll.c b/drivers/clk/imx/clk-fracn-gppll.c
new file mode 100644
index 000000000000..57b38147f05a
--- /dev/null
+++ b/drivers/clk/imx/clk-fracn-gppll.c
@@ -0,0 +1,324 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2021 NXP
+ */
+
+#include <asm/div64.h>
+#include <linux/bitfield.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+
+#include "clk.h"
+
+#define PLL_CTRL 0x0
+#define CLKMUX_BYPASS BIT(2)
+#define CLKMUX_EN BIT(1)
+#define POWERUP_MASK BIT(0)
+
+#define PLL_ANA_PRG 0x10
+#define PLL_SPREAD_SPECTRUM 0x30
+
+#define PLL_NUMERATOR 0x40
+#define PLL_MFN_MASK GENMASK(31, 2)
+
+#define PLL_DENOMINATOR 0x50
+#define PLL_MFD_MASK GENMASK(29, 0)
+
+#define PLL_DIV 0x60
+#define PLL_MFI_MASK GENMASK(24, 16)
+#define PLL_RDIV_MASK GENMASK(15, 13)
+#define PLL_ODIV_MASK GENMASK(7, 0)
+
+#define PLL_DFS_CTRL(x) (0x70 + (x) * 0x10)
+
+#define PLL_STATUS 0xF0
+#define LOCK_STATUS BIT(0)
+
+#define DFS_STATUS 0xF4
+
+#define LOCK_TIMEOUT_US 200
+
+#define PLL_FRACN_GP(_rate, _mfi, _mfn, _mfd, _rdiv, _odiv) \
+ { \
+ .rate = (_rate), \
+ .mfi = (_mfi), \
+ .mfn = (_mfn), \
+ .mfd = (_mfd), \
+ .rdiv = (_rdiv), \
+ .odiv = (_odiv), \
+ }
+
+struct clk_fracn_gppll {
+ struct clk_hw hw;
+ void __iomem *base;
+ const struct imx_fracn_gppll_rate_table *rate_table;
+ int rate_count;
+};
+
+/*
+ * Fvco = Fref * (MFI + MFN / MFD)
+ * Fout = Fvco / (rdiv * odiv)
+ */
+static const struct imx_fracn_gppll_rate_table fracn_tbl[] = {
+ PLL_FRACN_GP(650000000U, 81, 0, 0, 0, 3),
+ PLL_FRACN_GP(594000000U, 198, 0, 0, 0, 8),
+ PLL_FRACN_GP(560000000U, 70, 0, 0, 0, 3),
+ PLL_FRACN_GP(400000000U, 50, 0, 0, 0, 3),
+ PLL_FRACN_GP(393216000U, 81, 92, 100, 0, 5)
+};
+
+struct imx_fracn_gppll_clk imx_fracn_gppll = {
+ .rate_table = fracn_tbl,
+ .rate_count = ARRAY_SIZE(fracn_tbl),
+};
+EXPORT_SYMBOL_GPL(imx_fracn_gppll);
+
+static inline struct clk_fracn_gppll *to_clk_fracn_gppll(struct clk_hw *hw)
+{
+ return container_of(hw, struct clk_fracn_gppll, hw);
+}
+
+static const struct imx_fracn_gppll_rate_table *
+imx_get_pll_settings(struct clk_fracn_gppll *pll, unsigned long rate)
+{
+ const struct imx_fracn_gppll_rate_table *rate_table = pll->rate_table;
+ int i;
+
+ for (i = 0; i < pll->rate_count; i++)
+ if (rate == rate_table[i].rate)
+ return &rate_table[i];
+
+ return NULL;
+}
+
+static long clk_fracn_gppll_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ struct clk_fracn_gppll *pll = to_clk_fracn_gppll(hw);
+ const struct imx_fracn_gppll_rate_table *rate_table = pll->rate_table;
+ int i;
+
+ /* Assuming rate_table is in descending order */
+ for (i = 0; i < pll->rate_count; i++)
+ if (rate >= rate_table[i].rate)
+ return rate_table[i].rate;
+
+ /* return minimum supported value */
+ return rate_table[pll->rate_count - 1].rate;
+}
+
+static unsigned long clk_fracn_gppll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+ struct clk_fracn_gppll *pll = to_clk_fracn_gppll(hw);
+ const struct imx_fracn_gppll_rate_table *rate_table = pll->rate_table;
+ u32 pll_numerator, pll_denominator, pll_div;
+ u32 mfi, mfn, mfd, rdiv, odiv;
+ u64 fvco = parent_rate;
+ long rate = 0;
+ int i;
+
+ pll_numerator = readl_relaxed(pll->base + PLL_NUMERATOR);
+ mfn = FIELD_GET(PLL_MFN_MASK, pll_numerator);
+
+ pll_denominator = readl_relaxed(pll->base + PLL_DENOMINATOR);
+ mfd = FIELD_GET(PLL_MFD_MASK, pll_denominator);
+
+ pll_div = readl_relaxed(pll->base + PLL_DIV);
+ mfi = FIELD_GET(PLL_MFI_MASK, pll_div);
+
+ rdiv = FIELD_GET(PLL_RDIV_MASK, pll_div);
+ rdiv = rdiv + 1;
+ odiv = FIELD_GET(PLL_ODIV_MASK, pll_div);
+ switch (odiv) {
+ case 0:
+ odiv = 2;
+ break;
+ case 1:
+ odiv = 3;
+ break;
+ default:
+ break;
+ }
+
+ /*
+ * Sometimes, the recalculated rate has deviation due to
+ * the frac part. So find the accurate pll rate from the table
+ * first, if no match rate in the table, use the rate calculated
+ * from the equation below.
+ */
+ for (i = 0; i < pll->rate_count; i++) {
+ if (rate_table[i].mfn == mfn && rate_table[i].mfi == mfi &&
+ rate_table[i].mfd == mfd && rate_table[i].rdiv == rdiv &&
+ rate_table[i].odiv == odiv)
+ rate = rate_table[i].rate;
+ }
+
+ if (rate)
+ return (unsigned long)rate;
+
+ /* Fvco = Fref * (MFI + MFN / MFD) */
+ fvco = fvco * mfi * mfd + fvco * mfn;
+ do_div(fvco, mfd * rdiv * odiv);
+
+ return (unsigned long)fvco;
+}
+
+static int clk_fracn_gppll_wait_lock(struct clk_fracn_gppll *pll)
+{
+ u32 val;
+
+ return readl_poll_timeout(pll->base + PLL_STATUS, val,
+ val & LOCK_STATUS, 0, LOCK_TIMEOUT_US);
+}
+
+static int clk_fracn_gppll_set_rate(struct clk_hw *hw, unsigned long drate,
+ unsigned long prate)
+{
+ struct clk_fracn_gppll *pll = to_clk_fracn_gppll(hw);
+ const struct imx_fracn_gppll_rate_table *rate;
+ u32 tmp, pll_div, ana_mfn;
+ int ret;
+
+ rate = imx_get_pll_settings(pll, drate);
+
+ /* Disable output */
+ tmp = readl_relaxed(pll->base + PLL_CTRL);
+ tmp &= ~CLKMUX_EN;
+ writel_relaxed(tmp, pll->base + PLL_CTRL);
+
+ /* Power Down */
+ tmp &= ~POWERUP_MASK;
+ writel_relaxed(tmp, pll->base + PLL_CTRL);
+
+ /* Disable BYPASS */
+ tmp &= ~CLKMUX_BYPASS;
+ writel_relaxed(tmp, pll->base + PLL_CTRL);
+
+ pll_div = FIELD_PREP(PLL_RDIV_MASK, rate->rdiv) | rate->odiv |
+ FIELD_PREP(PLL_MFI_MASK, rate->mfi);
+ writel_relaxed(pll_div, pll->base + PLL_DIV);
+ writel_relaxed(rate->mfd, pll->base + PLL_DENOMINATOR);
+ writel_relaxed(FIELD_PREP(PLL_MFN_MASK, rate->mfn), pll->base + PLL_NUMERATOR);
+
+ /* Wait for 5us according to fracn mode pll doc */
+ udelay(5);
+
+ /* Enable Powerup */
+ tmp |= POWERUP_MASK;
+ writel_relaxed(tmp, pll->base + PLL_CTRL);
+
+ /* Wait Lock */
+ ret = clk_fracn_gppll_wait_lock(pll);
+ if (ret)
+ return ret;
+
+ /* Enable output */
+ tmp |= CLKMUX_EN;
+ writel_relaxed(tmp, pll->base + PLL_CTRL);
+
+ ana_mfn = readl_relaxed(pll->base + PLL_STATUS);
+ ana_mfn = FIELD_GET(PLL_MFN_MASK, ana_mfn);
+
+ WARN(ana_mfn != rate->mfn, "ana_mfn != rate->mfn\n");
+
+ return 0;
+}
+
+static int clk_fracn_gppll_prepare(struct clk_hw *hw)
+{
+ struct clk_fracn_gppll *pll = to_clk_fracn_gppll(hw);
+ u32 val;
+ int ret;
+
+ val = readl_relaxed(pll->base + PLL_CTRL);
+ if (val & POWERUP_MASK)
+ return 0;
+
+ val |= CLKMUX_BYPASS;
+ writel_relaxed(val, pll->base + PLL_CTRL);
+
+ val |= POWERUP_MASK;
+ writel_relaxed(val, pll->base + PLL_CTRL);
+
+ val |= CLKMUX_EN;
+ writel_relaxed(val, pll->base + PLL_CTRL);
+
+ ret = clk_fracn_gppll_wait_lock(pll);
+ if (ret)
+ return ret;
+
+ val &= ~CLKMUX_BYPASS;
+ writel_relaxed(val, pll->base + PLL_CTRL);
+
+ return 0;
+}
+
+static int clk_fracn_gppll_is_prepared(struct clk_hw *hw)
+{
+ struct clk_fracn_gppll *pll = to_clk_fracn_gppll(hw);
+ u32 val;
+
+ val = readl_relaxed(pll->base + PLL_CTRL);
+
+ return (val & POWERUP_MASK) ? 1 : 0;
+}
+
+static void clk_fracn_gppll_unprepare(struct clk_hw *hw)
+{
+ struct clk_fracn_gppll *pll = to_clk_fracn_gppll(hw);
+ u32 val;
+
+ val = readl_relaxed(pll->base + PLL_CTRL);
+ val &= ~POWERUP_MASK;
+ writel_relaxed(val, pll->base + PLL_CTRL);
+}
+
+static const struct clk_ops clk_fracn_gppll_ops = {
+ .prepare = clk_fracn_gppll_prepare,
+ .unprepare = clk_fracn_gppll_unprepare,
+ .is_prepared = clk_fracn_gppll_is_prepared,
+ .recalc_rate = clk_fracn_gppll_recalc_rate,
+ .round_rate = clk_fracn_gppll_round_rate,
+ .set_rate = clk_fracn_gppll_set_rate,
+};
+
+struct clk_hw *imx_clk_fracn_gppll(const char *name, const char *parent_name, void __iomem *base,
+ const struct imx_fracn_gppll_clk *pll_clk)
+{
+ struct clk_fracn_gppll *pll;
+ struct clk_hw *hw;
+ struct clk_init_data init;
+ int ret;
+
+ pll = kzalloc(sizeof(*pll), GFP_KERNEL);
+ if (!pll)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.flags = pll_clk->flags;
+ init.parent_names = &parent_name;
+ init.num_parents = 1;
+ init.ops = &clk_fracn_gppll_ops;
+
+ pll->base = base;
+ pll->hw.init = &init;
+ pll->rate_table = pll_clk->rate_table;
+ pll->rate_count = pll_clk->rate_count;
+
+ hw = &pll->hw;
+
+ ret = clk_hw_register(NULL, hw);
+ if (ret) {
+ pr_err("%s: failed to register pll %s %d\n", __func__, name, ret);
+ kfree(pll);
+ return ERR_PTR(ret);
+ }
+
+ return hw;
+}
+EXPORT_SYMBOL_GPL(imx_clk_fracn_gppll);
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index 63eb7c53b123..a7cbbcd1a3f4 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -72,6 +72,27 @@ extern struct imx_pll14xx_clk imx_1416x_pll;
extern struct imx_pll14xx_clk imx_1443x_pll;
extern struct imx_pll14xx_clk imx_1443x_dram_pll;

+/* NOTE: Rate table should be kept sorted in descending order. */
+struct imx_fracn_gppll_rate_table {
+ unsigned int rate;
+ unsigned int mfi;
+ unsigned int mfn;
+ unsigned int mfd;
+ unsigned int rdiv;
+ unsigned int odiv;
+};
+
+struct imx_fracn_gppll_clk {
+ const struct imx_fracn_gppll_rate_table *rate_table;
+ int rate_count;
+ int flags;
+};
+
+struct clk_hw *imx_clk_fracn_gppll(const char *name, const char *parent_name, void __iomem *base,
+ const struct imx_fracn_gppll_clk *pll_clk);
+
+extern struct imx_fracn_gppll_clk imx_fracn_gppll;
+
#define imx_clk_cpu(name, parent_name, div, mux, pll, step) \
to_clk(imx_clk_hw_cpu(name, parent_name, div, mux, pll, step))

--
2.25.1