[PATCH v8 08/21] clk: tegra: periph: Add restore_context support

[Sowjanya Komatineni]

This patch implements restore_context support for clk-periph and
clk-sdmmc-mux clock operations to restore clock parent and rates
on system resume.

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

So on system resume, clocks parent and rate are restored back to
the context before suspend based on cached data.

Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
---
 drivers/clk/tegra/clk-periph.c    | 18 ++++++++++++++++++
 drivers/clk/tegra/clk-sdmmc-mux.c | 12 ++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/drivers/clk/tegra/clk-periph.c b/drivers/clk/tegra/clk-periph.c
index 58437da25156..c9d28cbadccc 100644
--- a/drivers/clk/tegra/clk-periph.c
+++ b/drivers/clk/tegra/clk-periph.c
@@ -3,6 +3,7 @@
  * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
  */
 
+#include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/export.h>
 #include <linux/slab.h>
@@ -99,6 +100,20 @@ static void clk_periph_disable(struct clk_hw *hw)
 	gate_ops->disable(gate_hw);
 }
 
+static void clk_periph_restore_context(struct clk_hw *hw)
+{
+	struct tegra_clk_periph *periph = to_clk_periph(hw);
+	const struct clk_ops *div_ops = periph->div_ops;
+	struct clk_hw *div_hw = &periph->divider.hw;
+	struct clk_hw *parent = clk_hw_get_parent(hw);
+	int parent_id = clk_hw_get_parent_index(hw, parent);
+
+	if (!(periph->gate.flags & TEGRA_PERIPH_NO_DIV))
+		div_ops->restore_context(div_hw);
+
+	clk_periph_set_parent(hw, parent_id);
+}
+
 const struct clk_ops tegra_clk_periph_ops = {
 	.get_parent = clk_periph_get_parent,
 	.set_parent = clk_periph_set_parent,
@@ -108,6 +123,7 @@ const struct clk_ops tegra_clk_periph_ops = {
 	.is_enabled = clk_periph_is_enabled,
 	.enable = clk_periph_enable,
 	.disable = clk_periph_disable,
+	.restore_context = clk_periph_restore_context,
 };
 
 static const struct clk_ops tegra_clk_periph_nodiv_ops = {
@@ -116,6 +132,7 @@ static const struct clk_ops tegra_clk_periph_nodiv_ops = {
 	.is_enabled = clk_periph_is_enabled,
 	.enable = clk_periph_enable,
 	.disable = clk_periph_disable,
+	.restore_context = clk_periph_restore_context,
 };
 
 static const struct clk_ops tegra_clk_periph_no_gate_ops = {
@@ -124,6 +141,7 @@ static const struct clk_ops tegra_clk_periph_no_gate_ops = {
 	.recalc_rate = clk_periph_recalc_rate,
 	.round_rate = clk_periph_round_rate,
 	.set_rate = clk_periph_set_rate,
+	.restore_context = clk_periph_restore_context,
 };
 
 static struct clk *_tegra_clk_register_periph(const char *name,
diff --git a/drivers/clk/tegra/clk-sdmmc-mux.c b/drivers/clk/tegra/clk-sdmmc-mux.c
index a5cd3e31dbae..8db48966b100 100644
--- a/drivers/clk/tegra/clk-sdmmc-mux.c
+++ b/drivers/clk/tegra/clk-sdmmc-mux.c
@@ -194,6 +194,17 @@ static void clk_sdmmc_mux_disable(struct clk_hw *hw)
 	gate_ops->disable(gate_hw);
 }
 
+static void clk_sdmmc_mux_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);
+	int parent_id = clk_hw_get_parent_index(hw, parent);
+
+	clk_sdmmc_mux_set_parent(hw, parent_id);
+	clk_sdmmc_mux_set_rate(hw, rate, parent_rate);
+}
+
 static const struct clk_ops tegra_clk_sdmmc_mux_ops = {
 	.get_parent = clk_sdmmc_mux_get_parent,
 	.set_parent = clk_sdmmc_mux_set_parent,
@@ -203,6 +214,7 @@ static const struct clk_ops tegra_clk_sdmmc_mux_ops = {
 	.is_enabled = clk_sdmmc_mux_is_enabled,
 	.enable = clk_sdmmc_mux_enable,
 	.disable = clk_sdmmc_mux_disable,
+	.restore_context = clk_sdmmc_mux_restore_context,
 };
 
 struct clk *tegra_clk_register_sdmmc_mux_div(const char *name,
-- 
2.7.4