linux-kernel - [PATCH V6 10/21] clk: tegra: clk-super: Add save and restore support

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Message-ID: <1563738060-30213-11-git-send-email-skomatineni@nvidia.com>
Date:   Sun, 21 Jul 2019 12:40:49 -0700
From:   Sowjanya Komatineni <skomatineni@...dia.com>
To:     <thierry.reding@...il.com>, <jonathanh@...dia.com>,
        <tglx@...utronix.de>, <jason@...edaemon.net>,
        <marc.zyngier@....com>, <linus.walleij@...aro.org>,
        <stefan@...er.ch>, <mark.rutland@....com>
CC:     <pdeschrijver@...dia.com>, <pgaikwad@...dia.com>,
        <sboyd@...nel.org>, <linux-clk@...r.kernel.org>,
        <linux-gpio@...r.kernel.org>, <jckuo@...dia.com>,
        <josephl@...dia.com>, <talho@...dia.com>, <skomatineni@...dia.com>,
        <linux-tegra@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <mperttunen@...dia.com>, <spatra@...dia.com>, <robh+dt@...nel.org>,
        <digetx@...il.com>, <devicetree@...r.kernel.org>
Subject: [PATCH V6 10/21] clk: tegra: clk-super: Add save and restore support

This patch implements save and restore context for clk_super_mux
and clk_super.

During system supend, core power goes off the and context of Tegra
CAR registers is lost.

So during suspend entry, context of super clock registers are saved
through save_context clk_ops and are restored through restore_context
clk_ops to have them in same state as before suspend.

Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
---
 drivers/clk/tegra/clk-super.c | 40 ++++++++++++++++++++++++++++++++++++++++
 drivers/clk/tegra/clk.h       |  1 +
 2 files changed, 41 insertions(+)

diff --git a/drivers/clk/tegra/clk-super.c b/drivers/clk/tegra/clk-super.c
index d73c587e4853..84492afd3f1d 100644
--- a/drivers/clk/tegra/clk-super.c
+++ b/drivers/clk/tegra/clk-super.c
@@ -121,9 +121,27 @@ static int clk_super_set_parent(struct clk_hw *hw, u8 index)
 	return err;
 }
 
+static int clk_super_mux_save_context(struct clk_hw *hw)
+{
+	struct tegra_clk_super_mux *mux = to_clk_super_mux(hw);
+
+	mux->parent_index_ctx = clk_super_get_parent(hw);
+
+	return 0;
+}
+
+static void clk_super_mux_restore_context(struct clk_hw *hw)
+{
+	struct tegra_clk_super_mux *mux = to_clk_super_mux(hw);
+
+	clk_super_set_parent(hw, mux->parent_index_ctx);
+}
+
 static const struct clk_ops tegra_clk_super_mux_ops = {
 	.get_parent = clk_super_get_parent,
 	.set_parent = clk_super_set_parent,
+	.save_context = clk_super_mux_save_context,
+	.restore_context = clk_super_mux_restore_context,
 };
 
 static long clk_super_round_rate(struct clk_hw *hw, unsigned long rate,
@@ -159,12 +177,34 @@ static int clk_super_set_rate(struct clk_hw *hw, unsigned long rate,
 	return super->div_ops->set_rate(div_hw, rate, parent_rate);
 }
 
+static int clk_super_save_context(struct clk_hw *hw)
+{
+	struct tegra_clk_super_mux *super = to_clk_super_mux(hw);
+	struct clk_hw *div_hw = &super->frac_div.hw;
+
+	super->parent_index_ctx = clk_super_get_parent(hw);
+
+	return super->div_ops->save_context(div_hw);
+}
+
+static void clk_super_restore_context(struct clk_hw *hw)
+{
+	struct tegra_clk_super_mux *super = to_clk_super_mux(hw);
+	struct clk_hw *div_hw = &super->frac_div.hw;
+
+	clk_super_set_parent(hw, super->parent_index_ctx);
+
+	super->div_ops->restore_context(div_hw);
+}
+
 const struct clk_ops tegra_clk_super_ops = {
 	.get_parent = clk_super_get_parent,
 	.set_parent = clk_super_set_parent,
 	.set_rate = clk_super_set_rate,
 	.round_rate = clk_super_round_rate,
 	.recalc_rate = clk_super_recalc_rate,
+	.save_context = clk_super_save_context,
+	.restore_context = clk_super_restore_context,
 };
 
 struct clk *tegra_clk_register_super_mux(const char *name,
diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
index c357b49e49b0..562a3ee2d537 100644
--- a/drivers/clk/tegra/clk.h
+++ b/drivers/clk/tegra/clk.h
@@ -708,6 +708,7 @@ struct tegra_clk_super_mux {
 	u8		div2_index;
 	u8		pllx_index;
 	spinlock_t	*lock;
+	u8		parent_index_ctx;
 };
 
 #define to_clk_super_mux(_hw) container_of(_hw, struct tegra_clk_super_mux, hw)
-- 
2.7.4