clk: mediatek: Add new clock driver to handle FHCTL hardware

To implement frequency hopping and spread spectrum clocking
function, we introduce new clock type and APIs to handle
FHCTL hardware.

Co-developed-by: Edward-JW Yang <edward-jw.yang@mediatek.com>
Signed-off-by: Edward-JW Yang <edward-jw.yang@mediatek.com>
Signed-off-by: Johnson Wang <johnson.wang@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20221121122957.21611-4-johnson.wang@mediatek.com
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>

1 files changed, 244 insertions, 0 deletions

diff --git a/drivers/clk/mediatek/clk-fhctl.c b/drivers/clk/mediatek/clk-fhctl.c
new file mode 100644
index 000000000000..4f271acef5fe
--- /dev/null
+++ b/drivers/clk/mediatek/clk-fhctl.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022 MediaTek Inc.
+ * Author: Edward-JW Yang <edward-jw.yang@mediatek.com>
+ */
+
+#include <linux/io.h>
+#include <linux/iopoll.h>
+
+#include "clk-mtk.h"
+#include "clk-pllfh.h"
+#include "clk-fhctl.h"
+
+#define PERCENT_TO_DDSLMT(dds, percent_m10) \
+	((((dds) * (percent_m10)) >> 5) / 100)
+
+static const struct fhctl_offset fhctl_offset = {
+	.offset_hp_en = 0x0,
+	.offset_clk_con = 0x8,
+	.offset_rst_con = 0xc,
+	.offset_slope0 = 0x10,
+	.offset_slope1 = 0x14,
+	.offset_cfg = 0x0,
+	.offset_updnlmt = 0x4,
+	.offset_dds = 0x8,
+	.offset_dvfs = 0xc,
+	.offset_mon = 0x10,
+};
+
+const struct fhctl_offset *fhctl_get_offset_table(void)
+{
+	return &fhctl_offset;
+}
+
+static void dump_hw(struct mtk_clk_pll *pll, struct fh_pll_regs *regs,
+		    const struct fh_pll_data *data)
+{
+	pr_info("hp_en<%x>,clk_con<%x>,slope0<%x>,slope1<%x>\n",
+		readl(regs->reg_hp_en), readl(regs->reg_clk_con),
+		readl(regs->reg_slope0), readl(regs->reg_slope1));
+	pr_info("cfg<%x>,lmt<%x>,dds<%x>,dvfs<%x>,mon<%x>\n",
+		readl(regs->reg_cfg), readl(regs->reg_updnlmt),
+		readl(regs->reg_dds), readl(regs->reg_dvfs),
+		readl(regs->reg_mon));
+	pr_info("pcw<%x>\n", readl(pll->pcw_addr));
+}
+
+static int fhctl_set_ssc_regs(struct mtk_clk_pll *pll, struct fh_pll_regs *regs,
+			      const struct fh_pll_data *data, u32 rate)
+{
+	u32 updnlmt_val, r;
+
+	writel((readl(regs->reg_cfg) & ~(data->frddsx_en)), regs->reg_cfg);
+	writel((readl(regs->reg_cfg) & ~(data->sfstrx_en)), regs->reg_cfg);
+	writel((readl(regs->reg_cfg) & ~(data->fhctlx_en)), regs->reg_cfg);
+
+	if (rate > 0) {
+		/* Set the relative parameter registers (dt/df/upbnd/downbnd) */
+		r = readl(regs->reg_cfg);
+		r &= ~(data->msk_frddsx_dys);
+		r |= (data->df_val << (ffs(data->msk_frddsx_dys) - 1));
+		writel(r, regs->reg_cfg);
+
+		r = readl(regs->reg_cfg);
+		r &= ~(data->msk_frddsx_dts);
+		r |= (data->dt_val << (ffs(data->msk_frddsx_dts) - 1));
+		writel(r, regs->reg_cfg);
+
+		writel((readl(pll->pcw_addr) & data->dds_mask) | data->tgl_org,
+			regs->reg_dds);
+
+		/* Calculate UPDNLMT */
+		updnlmt_val = PERCENT_TO_DDSLMT((readl(regs->reg_dds) &
+						 data->dds_mask), rate) <<
+						 data->updnlmt_shft;
+
+		writel(updnlmt_val, regs->reg_updnlmt);
+		writel(readl(regs->reg_hp_en) | BIT(data->fh_id),
+		       regs->reg_hp_en);
+		/* Enable SSC */
+		writel(readl(regs->reg_cfg) | data->frddsx_en, regs->reg_cfg);
+		/* Enable Hopping control */
+		writel(readl(regs->reg_cfg) | data->fhctlx_en, regs->reg_cfg);
+
+	} else {
+		/* Switch to APMIXEDSYS control */
+		writel(readl(regs->reg_hp_en) & ~BIT(data->fh_id),
+		       regs->reg_hp_en);
+		/* Wait for DDS to be stable */
+		udelay(30);
+	}
+
+	return 0;
+}
+
+static int hopping_hw_flow(struct mtk_clk_pll *pll, struct fh_pll_regs *regs,
+			   const struct fh_pll_data *data,
+			   struct fh_pll_state *state, unsigned int new_dds)
+{
+	u32 dds_mask = data->dds_mask;
+	u32 mon_dds = 0;
+	u32 con_pcw_tmp;
+	int ret;
+
+	if (state->ssc_rate)
+		fhctl_set_ssc_regs(pll, regs, data, 0);
+
+	writel((readl(pll->pcw_addr) & dds_mask) | data->tgl_org,
+		regs->reg_dds);
+
+	writel(readl(regs->reg_cfg) | data->sfstrx_en, regs->reg_cfg);
+	writel(readl(regs->reg_cfg) | data->fhctlx_en, regs->reg_cfg);
+	writel(data->slope0_value, regs->reg_slope0);
+	writel(data->slope1_value, regs->reg_slope1);
+
+	writel(readl(regs->reg_hp_en) | BIT(data->fh_id), regs->reg_hp_en);
+	writel((new_dds) | (data->dvfs_tri), regs->reg_dvfs);
+
+	/* Wait 1000 us until DDS stable */
+	ret = readl_poll_timeout_atomic(regs->reg_mon, mon_dds,
+				       (mon_dds & dds_mask) == new_dds,
+					10, 1000);
+	if (ret) {
+		pr_warn("%s: FHCTL hopping timeout\n", pll->data->name);
+		dump_hw(pll, regs, data);
+	}
+
+	con_pcw_tmp = readl(pll->pcw_addr) & (~dds_mask);
+	con_pcw_tmp = (con_pcw_tmp | (readl(regs->reg_mon) & dds_mask) |
+		       data->pcwchg);
+
+	writel(con_pcw_tmp, pll->pcw_addr);
+	writel(readl(regs->reg_hp_en) & ~BIT(data->fh_id), regs->reg_hp_en);
+
+	if (state->ssc_rate)
+		fhctl_set_ssc_regs(pll, regs, data, state->ssc_rate);
+
+	return ret;
+}
+
+static unsigned int __get_postdiv(struct mtk_clk_pll *pll)
+{
+	unsigned int regval;
+
+	regval = readl(pll->pd_addr) >> pll->data->pd_shift;
+	regval &= POSTDIV_MASK;
+
+	return BIT(regval);
+}
+
+static void __set_postdiv(struct mtk_clk_pll *pll, unsigned int postdiv)
+{
+	unsigned int regval;
+
+	regval = readl(pll->pd_addr);
+	regval &= ~(POSTDIV_MASK << pll->data->pd_shift);
+	regval |= (ffs(postdiv) - 1) << pll->data->pd_shift;
+	writel(regval, pll->pd_addr);
+}
+
+static int fhctl_hopping(struct mtk_fh *fh, unsigned int new_dds,
+			 unsigned int postdiv)
+{
+	const struct fh_pll_data *data = &fh->pllfh_data->data;
+	struct fh_pll_state *state = &fh->pllfh_data->state;
+	struct fh_pll_regs *regs = &fh->regs;
+	struct mtk_clk_pll *pll = &fh->clk_pll;
+	spinlock_t *lock = fh->lock;
+	unsigned int pll_postdiv;
+	unsigned long flags = 0;
+	int ret;
+
+	if (postdiv) {
+		pll_postdiv = __get_postdiv(pll);
+
+		if (postdiv > pll_postdiv)
+			__set_postdiv(pll, postdiv);
+	}
+
+	spin_lock_irqsave(lock, flags);
+
+	ret = hopping_hw_flow(pll, regs, data, state, new_dds);
+
+	spin_unlock_irqrestore(lock, flags);
+
+	if (postdiv && postdiv < pll_postdiv)
+		__set_postdiv(pll, postdiv);
+
+	return ret;
+}
+
+static int fhctl_ssc_enable(struct mtk_fh *fh, u32 rate)
+{
+	const struct fh_pll_data *data = &fh->pllfh_data->data;
+	struct fh_pll_state *state = &fh->pllfh_data->state;
+	struct fh_pll_regs *regs = &fh->regs;
+	struct mtk_clk_pll *pll = &fh->clk_pll;
+	spinlock_t *lock = fh->lock;
+	unsigned long flags = 0;
+
+	spin_lock_irqsave(lock, flags);
+
+	fhctl_set_ssc_regs(pll, regs, data, rate);
+	state->ssc_rate = rate;
+
+	spin_unlock_irqrestore(lock, flags);
+
+	return 0;
+}
+
+static const struct fh_operation fhctl_ops = {
+	.hopping = fhctl_hopping,
+	.ssc_enable = fhctl_ssc_enable,
+};
+
+const struct fh_operation *fhctl_get_ops(void)
+{
+	return &fhctl_ops;
+}
+
+void fhctl_hw_init(struct mtk_fh *fh)
+{
+	const struct fh_pll_data data = fh->pllfh_data->data;
+	struct fh_pll_state state = fh->pllfh_data->state;
+	struct fh_pll_regs regs = fh->regs;
+	u32 val;
+
+	/* initial hw register */
+	val = readl(regs.reg_clk_con) | BIT(data.fh_id);
+	writel(val, regs.reg_clk_con);
+
+	val = readl(regs.reg_rst_con) & ~BIT(data.fh_id);
+	writel(val, regs.reg_rst_con);
+	val = readl(regs.reg_rst_con) | BIT(data.fh_id);
+	writel(val, regs.reg_rst_con);
+
+	writel(0x0, regs.reg_cfg);
+	writel(0x0, regs.reg_updnlmt);
+	writel(0x0, regs.reg_dds);
+
+	/* enable ssc if needed */
+	if (state.ssc_rate)
+		fh->ops->ssc_enable(fh, state.ssc_rate);
+}