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

Sowjanya Komatineni
2019-07-21T19:42:17Z

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@nvidia.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