linux-kernel - [PATCH v10 2/5] clk: meson: introduce new pll power-on sequence for A1 SoC family

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Date:   Mon, 13 Mar 2023 23:12:56 +0300
From:   Dmitry Rokosov <ddrokosov@...rdevices.ru>
To:     <neil.armstrong@...aro.org>, <jbrunet@...libre.com>,
        <mturquette@...libre.com>, <sboyd@...nel.org>,
        <robh+dt@...nel.org>, <krzysztof.kozlowski+dt@...aro.org>,
        <khilman@...libre.com>, <martin.blumenstingl@...glemail.com>
CC:     <jian.hu@...ogic.com>, <kernel@...rdevices.ru>,
        <rockosov@...il.com>, <linux-amlogic@...ts.infradead.org>,
        <linux-clk@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Dmitry Rokosov <ddrokosov@...rdevices.ru>
Subject: [PATCH v10 2/5] clk: meson: introduce new pll power-on sequence for A1 SoC family

Modern meson PLL IPs are a little bit different from early known PLLs.
The main difference is located in the init/enable/disable sequences; the
rate logic is the same.

In A1 PLL, the PLL enable sequence is different, so add new optional pll
reg bits and use the new power-on sequence to enable the PLL:
    1. enable the pll, delay for 10us
    2. enable the pll self-adaption current module, delay for 40us
    3. enable the lock detect module

Signed-off-by: Jian Hu <jian.hu@...ogic.com>
Acked-by: Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Signed-off-by: Dmitry Rokosov <ddrokosov@...rdevices.ru>
---
 drivers/clk/meson/clk-pll.c | 23 +++++++++++++++++++++++
 drivers/clk/meson/clk-pll.h |  2 ++
 2 files changed, 25 insertions(+)

diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c
index 314ca945a4d0..56ec2210f1ad 100644
--- a/drivers/clk/meson/clk-pll.c
+++ b/drivers/clk/meson/clk-pll.c
@@ -358,6 +358,25 @@ static int meson_clk_pll_enable(struct clk_hw *hw)
 	if (MESON_PARM_APPLICABLE(&pll->rst))
 		meson_parm_write(clk->map, &pll->rst, 0);
 
+	/*
+	 * Compared with the previous SoCs, self-adaption current module
+	 * is newly added for A1, keep the new power-on sequence to enable the
+	 * PLL. The sequence is:
+	 * 1. enable the pll, delay for 10us
+	 * 2. enable the pll self-adaption current module, delay for 40us
+	 * 3. enable the lock detect module
+	 */
+	if (MESON_PARM_APPLICABLE(&pll->current_en)) {
+		usleep_range(10, 20);
+		meson_parm_write(clk->map, &pll->current_en, 1);
+		usleep_range(40, 50);
+	};
+
+	if (MESON_PARM_APPLICABLE(&pll->l_detect)) {
+		meson_parm_write(clk->map, &pll->l_detect, 1);
+		meson_parm_write(clk->map, &pll->l_detect, 0);
+	}
+
 	if (meson_clk_pll_wait_lock(hw))
 		return -EIO;
 
@@ -375,6 +394,10 @@ static void meson_clk_pll_disable(struct clk_hw *hw)
 
 	/* Disable the pll */
 	meson_parm_write(clk->map, &pll->en, 0);
+
+	/* Disable PLL internal self-adaption current module */
+	if (MESON_PARM_APPLICABLE(&pll->current_en))
+		meson_parm_write(clk->map, &pll->current_en, 0);
 }
 
 static int meson_clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
diff --git a/drivers/clk/meson/clk-pll.h b/drivers/clk/meson/clk-pll.h
index 367efd0f6410..a2228c0fdce5 100644
--- a/drivers/clk/meson/clk-pll.h
+++ b/drivers/clk/meson/clk-pll.h
@@ -36,6 +36,8 @@ struct meson_clk_pll_data {
 	struct parm frac;
 	struct parm l;
 	struct parm rst;
+	struct parm current_en;
+	struct parm l_detect;
 	const struct reg_sequence *init_regs;
 	unsigned int init_count;
 	const struct pll_params_table *table;
-- 
2.36.0