clk: tegra: periph: Add restore_context support

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.

Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/clk/tegra/clk-periph.c b/drivers/clk/tegra/clk-periph.c
index 58437da2515652beddd9a9f89ad969188bf05bb4..67620c7ecd9ee299b274d9784fa5e675e08e4e8e 100644 (file)
--- 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 +100,23 @@ 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;
+       int parent_id;
+
+       parent_id = clk_hw_get_parent_index(hw);
+       if (WARN_ON(parent_id < 0))
+               return;
+
+       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 +126,7 @@ 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 +135,7 @@ 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 +144,7 @@ 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 a5cd3e31dbaed5a44ffb616275a7bd7db77cf0ab..316912d3b1a4f0e4cc206f104f5219cc25f287d1 100644 (file)
--- a/drivers/clk/tegra/clk-sdmmc-mux.c
+++ b/drivers/clk/tegra/clk-sdmmc-mux.c
@@ -194,6 +194,21 @@ 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;
+
+       parent_id = clk_hw_get_parent_index(hw);
+       if (WARN_ON(parent_id < 0))
+               return;
+
+       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 +218,7 @@ 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,