linux-kernel - [PATCH v7 03/20] clk: tegra: divider: Save and restore divider rate

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Date:   Tue, 30 Jul 2019 17:20:07 -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 v7 03/20] clk: tegra: divider: Save and restore divider rate

This patch implements context restore for clock divider.

During system suspend, core power goes off and looses the settings
of the Tegra CAR controller registers.

So on resume, clock dividers are restored back for normal operation.

Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
---
 drivers/clk/tegra/clk-divider.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/clk/tegra/clk-divider.c b/drivers/clk/tegra/clk-divider.c
index e76731fb7d69..ca0de5f11f84 100644
--- a/drivers/clk/tegra/clk-divider.c
+++ b/drivers/clk/tegra/clk-divider.c
@@ -109,10 +109,21 @@ static int clk_frac_div_set_rate(struct clk_hw *hw, unsigned long rate,
 	return 0;
 }
 
+static void clk_divider_restore_context(struct clk_hw *hw)
+{
+	struct clk_hw *parent = clk_hw_get_parent(hw);
+	unsigned long parent_rate = clk_hw_get_rate(parent);
+	unsigned long rate = clk_hw_get_rate(hw);
+
+	if (clk_frac_div_set_rate(hw, rate, parent_rate) < 0)
+		WARN_ON(1);
+}
+
 const struct clk_ops tegra_clk_frac_div_ops = {
 	.recalc_rate = clk_frac_div_recalc_rate,
 	.set_rate = clk_frac_div_set_rate,
 	.round_rate = clk_frac_div_round_rate,
+	.restore_context = clk_divider_restore_context,
 };
 
 struct clk *tegra_clk_register_divider(const char *name,
-- 
2.7.4