linux-kernel - [PATCH V3 05/17] clk: tegra: pllout: save and restore pllout context

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Message-ID: <1560843991-24123-6-git-send-email-skomatineni@nvidia.com>
Date:   Tue, 18 Jun 2019 00:46:19 -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 V3 05/17] clk: tegra: pllout: save and restore pllout context

This patch implements save and restore of pllout context.

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

So during suspend entry the state of pllout is saved and on resume
it is restored back to have pllout in same state as before suspend.

pllout rate is saved and restore in clock divider so it will be at
same rate as before suspend when pllout state is restored.

Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
---
 drivers/clk/tegra/clk-pll-out.c | 28 ++++++++++++++++++++++++++++
 drivers/clk/tegra/clk.h         |  3 +++
 2 files changed, 31 insertions(+)

diff --git a/drivers/clk/tegra/clk-pll-out.c b/drivers/clk/tegra/clk-pll-out.c
index 35f2bf00e1e6..52d140379ce3 100644
--- a/drivers/clk/tegra/clk-pll-out.c
+++ b/drivers/clk/tegra/clk-pll-out.c
@@ -69,10 +69,38 @@ static void clk_pll_out_disable(struct clk_hw *hw)
 		spin_unlock_irqrestore(pll_out->lock, flags);
 }
 
+static int tegra_clk_pll_out_save_context(struct clk_hw *hw)
+{
+	struct tegra_clk_pll_out *pll_out = to_clk_pll_out(hw);
+
+	if (!strcmp(__clk_get_name(hw->clk), "pll_re_out1"))
+		pll_out->pllout_ctx = readl_relaxed(pll_out->reg);
+	else
+		pll_out->pllout_ctx = clk_hw_get_rate(hw);
+
+	return 0;
+}
+
+static void tegra_clk_pll_out_restore_context(struct clk_hw *hw)
+{
+	struct tegra_clk_pll_out *pll_out = to_clk_pll_out(hw);
+
+	if (!strcmp(__clk_get_name(hw->clk), "pll_re_out1")) {
+		writel_relaxed(pll_out->pllout_ctx, pll_out->reg);
+	} else {
+		if (!__clk_get_enable_count(hw->clk))
+			clk_pll_out_disable(hw);
+		else
+			clk_pll_out_enable(hw);
+	}
+}
+
 const struct clk_ops tegra_clk_pll_out_ops = {
 	.is_enabled = clk_pll_out_is_enabled,
 	.enable = clk_pll_out_enable,
 	.disable = clk_pll_out_disable,
+	.save_context = tegra_clk_pll_out_save_context,
+	.restore_context = tegra_clk_pll_out_restore_context,
 };
 
 struct clk *tegra_clk_register_pll_out(const char *name,
diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
index 83623f5f55f3..b47f373c35ad 100644
--- a/drivers/clk/tegra/clk.h
+++ b/drivers/clk/tegra/clk.h
@@ -439,6 +439,8 @@ struct clk *tegra_clk_register_pllu_tegra210(const char *name,
  * @rst_bit_idx:	bit to reset PLL divider
  * @lock:		register lock
  * @flags:		hardware-specific flags
+ * @pllout_ctx:		pllout context to save and restore during suspend
+ *			and resume
  */
 struct tegra_clk_pll_out {
 	struct clk_hw	hw;
@@ -447,6 +449,7 @@ struct tegra_clk_pll_out {
 	u8		rst_bit_idx;
 	spinlock_t	*lock;
 	u8		flags;
+	unsigned int	pllout_ctx;
 };
 
 #define to_clk_pll_out(_hw) container_of(_hw, struct tegra_clk_pll_out, hw)
-- 
2.7.4