[PATCH v3 3/4] clk: ti: Add functions to save/restore clk context

From: Keerthy
Date: Thu Jun 21 2018 - 04:41:41 EST

From: Russ Dill <Russ.Dill@xxxxxx>

SoCs like AM43XX lose clock registers context during RTC-only
suspend. Hence add functions to save/restore the clock registers
context.

Signed-off-by: Keerthy <j-keerthy@xxxxxx>
Signed-off-by: Russ Dill <Russ.Dill@xxxxxx>
---

Changes in v2:

* Replaced clk_dflt_restore instances to clk_gate_restore_context

drivers/clk/ti/clock.h | 2 +
drivers/clk/ti/divider.c | 36 ++++++++++++++
drivers/clk/ti/dpll.c | 6 +++
drivers/clk/ti/dpll3xxx.c | 124 ++++++++++++++++++++++++++++++++++++++++++++++
drivers/clk/ti/gate.c | 3 ++
drivers/clk/ti/mux.c | 29 +++++++++++
include/linux/clk/ti.h | 6 +++
7 files changed, 206 insertions(+)

diff --git a/drivers/clk/ti/clock.h b/drivers/clk/ti/clock.h
index b582780..26fbdf2 100644
--- a/drivers/clk/ti/clock.h
+++ b/drivers/clk/ti/clock.h
@@ -24,6 +24,7 @@ struct clk_omap_divider {
u8 flags;
s8 latch;
const struct clk_div_table *table;
+ u32 context;
};

#define to_clk_omap_divider(_hw) container_of(_hw, struct clk_omap_divider, hw)
@@ -36,6 +37,7 @@ struct clk_omap_mux {
u8 shift;
s8 latch;
u8 flags;
+ u8 saved_parent;
};

#define to_clk_omap_mux(_hw) container_of(_hw, struct clk_omap_mux, hw)
diff --git a/drivers/clk/ti/divider.c b/drivers/clk/ti/divider.c
index aaa277d..4418e0d 100644
--- a/drivers/clk/ti/divider.c
+++ b/drivers/clk/ti/divider.c
@@ -268,10 +268,46 @@ static int ti_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
return 0;
}

+/**
+ * clk_divider_save_context - Save the divider value
+ * @hw: pointer struct clk_hw
+ *
+ * Save the divider value
+ */
+static int clk_divider_save_context(struct clk_hw *hw)
+{
+ struct clk_omap_divider *divider = to_clk_omap_divider(hw);
+ u32 val;
+
+ val = ti_clk_ll_ops->clk_readl(&divider->reg) >> divider->shift;
+ divider->context = val & div_mask(divider);
+
+ return 0;
+}
+
+/**
+ * clk_divider_restore_context - restore the saved the divider value
+ * @hw: pointer struct clk_hw
+ *
+ * Restore the saved the divider value
+ */
+static void clk_divider_restore_context(struct clk_hw *hw)
+{
+ struct clk_omap_divider *divider = to_clk_omap_divider(hw);
+ u32 val;
+
+ val = ti_clk_ll_ops->clk_readl(&divider->reg);
+ val &= ~(div_mask(divider) << divider->shift);
+ val |= divider->context << divider->shift;
+ ti_clk_ll_ops->clk_writel(val, &divider->reg);
+}
+
const struct clk_ops ti_clk_divider_ops = {
.recalc_rate = ti_clk_divider_recalc_rate,
.round_rate = ti_clk_divider_round_rate,
.set_rate = ti_clk_divider_set_rate,
+ .save_context = clk_divider_save_context,
+ .restore_context = clk_divider_restore_context,
};

static struct clk *_register_divider(struct device *dev, const char *name,
diff --git a/drivers/clk/ti/dpll.c b/drivers/clk/ti/dpll.c
index 7d33ca9..b1c4d8a 100644
--- a/drivers/clk/ti/dpll.c
+++ b/drivers/clk/ti/dpll.c
@@ -39,6 +39,8 @@
.set_rate_and_parent = &omap3_noncore_dpll_set_rate_and_parent,
.determine_rate = &omap4_dpll_regm4xen_determine_rate,
.get_parent = &omap2_init_dpll_parent,
+ .save_context = &omap3_core_dpll_save_context,
+ .restore_context = &omap3_core_dpll_restore_context,
};
#else
static const struct clk_ops dpll_m4xen_ck_ops = {};
@@ -62,6 +64,8 @@
.set_rate_and_parent = &omap3_noncore_dpll_set_rate_and_parent,
.determine_rate = &omap3_noncore_dpll_determine_rate,
.get_parent = &omap2_init_dpll_parent,
+ .save_context = &omap3_noncore_dpll_save_context,
+ .restore_context = &omap3_noncore_dpll_restore_context,
};

static const struct clk_ops dpll_no_gate_ck_ops = {
@@ -72,6 +76,8 @@
.set_parent = &omap3_noncore_dpll_set_parent,
.set_rate_and_parent = &omap3_noncore_dpll_set_rate_and_parent,
.determine_rate = &omap3_noncore_dpll_determine_rate,
+ .save_context = &omap3_noncore_dpll_save_context,
+ .restore_context = &omap3_noncore_dpll_restore_context
};
#else
static const struct clk_ops dpll_core_ck_ops = {};
diff --git a/drivers/clk/ti/dpll3xxx.c b/drivers/clk/ti/dpll3xxx.c
index 4534de2..44b6b64 100644
--- a/drivers/clk/ti/dpll3xxx.c
+++ b/drivers/clk/ti/dpll3xxx.c
@@ -782,6 +782,130 @@ unsigned long omap3_clkoutx2_recalc(struct clk_hw *hw,
return rate;
}

+/**
+ * omap3_core_dpll_save_context - Save the m and n values of the divider
+ * @hw: pointer struct clk_hw
+ *
+ * Before the dpll registers are lost save the last rounded rate m and n
+ * and the enable mask.
+ */
+int omap3_core_dpll_save_context(struct clk_hw *hw)
+{
+ struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+ struct dpll_data *dd;
+ u32 v;
+
+ dd = clk->dpll_data;
+
+ v = ti_clk_ll_ops->clk_readl(&dd->control_reg);
+ clk->context = (v & dd->enable_mask) >> __ffs(dd->enable_mask);
+
+ if (clk->context == DPLL_LOCKED) {
+ v = ti_clk_ll_ops->clk_readl(&dd->mult_div1_reg);
+ dd->last_rounded_m = (v & dd->mult_mask) >>
+ __ffs(dd->mult_mask);
+ dd->last_rounded_n = ((v & dd->div1_mask) >>
+ __ffs(dd->div1_mask)) + 1;
+ }
+
+ return 0;
+}
+
+/**
+ * omap3_core_dpll_restore_context - restore the m and n values of the divider
+ * @hw: pointer struct clk_hw
+ *
+ * Restore the last rounded rate m and n
+ * and the enable mask.
+ */
+void omap3_core_dpll_restore_context(struct clk_hw *hw)
+{
+ struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+ const struct dpll_data *dd;
+ u32 v;
+
+ dd = clk->dpll_data;
+
+ if (clk->context == DPLL_LOCKED) {
+ _omap3_dpll_write_clken(clk, 0x4);
+ _omap3_wait_dpll_status(clk, 0);
+
+ v = ti_clk_ll_ops->clk_readl(&dd->mult_div1_reg);
+ v &= ~(dd->mult_mask | dd->div1_mask);
+ v |= dd->last_rounded_m << __ffs(dd->mult_mask);
+ v |= (dd->last_rounded_n - 1) << __ffs(dd->div1_mask);
+ ti_clk_ll_ops->clk_writel(v, &dd->mult_div1_reg);
+
+ _omap3_dpll_write_clken(clk, DPLL_LOCKED);
+ _omap3_wait_dpll_status(clk, 1);
+ } else {
+ _omap3_dpll_write_clken(clk, clk->context);
+ }
+}
+
+/**
+ * omap3_non_core_dpll_save_context - Save the m and n values of the divider
+ * @hw: pointer struct clk_hw
+ *
+ * Before the dpll registers are lost save the last rounded rate m and n
+ * and the enable mask.
+ */
+int omap3_noncore_dpll_save_context(struct clk_hw *hw)
+{
+ struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+ struct dpll_data *dd;
+ u32 v;
+
+ dd = clk->dpll_data;
+
+ v = ti_clk_ll_ops->clk_readl(&dd->control_reg);
+ clk->context = (v & dd->enable_mask) >> __ffs(dd->enable_mask);
+
+ if (clk->context == DPLL_LOCKED) {
+ v = ti_clk_ll_ops->clk_readl(&dd->mult_div1_reg);
+ dd->last_rounded_m = (v & dd->mult_mask) >>
+ __ffs(dd->mult_mask);
+ dd->last_rounded_n = ((v & dd->div1_mask) >>
+ __ffs(dd->div1_mask)) + 1;
+ }
+
+ return 0;
+}
+
+/**
+ * omap3_core_dpll_restore_context - restore the m and n values of the divider
+ * @hw: pointer struct clk_hw
+ *
+ * Restore the last rounded rate m and n
+ * and the enable mask.
+ */
+void omap3_noncore_dpll_restore_context(struct clk_hw *hw)
+{
+ struct clk_hw_omap *clk = to_clk_hw_omap(hw);
+ const struct dpll_data *dd;
+ u32 ctrl, mult_div1;
+
+ dd = clk->dpll_data;
+
+ ctrl = ti_clk_ll_ops->clk_readl(&dd->control_reg);
+ mult_div1 = ti_clk_ll_ops->clk_readl(&dd->mult_div1_reg);
+
+ if (clk->context == ((ctrl & dd->enable_mask) >>
+ __ffs(dd->enable_mask)) &&
+ dd->last_rounded_m == ((mult_div1 & dd->mult_mask) >>
+ __ffs(dd->mult_mask)) &&
+ dd->last_rounded_n == ((mult_div1 & dd->div1_mask) >>
+ __ffs(dd->div1_mask)) + 1) {
+ /* nothing to be done */
+ return;
+ }
+
+ if (clk->context == DPLL_LOCKED)
+ omap3_noncore_dpll_program(clk, 0);
+ else
+ _omap3_dpll_write_clken(clk, clk->context);
+}
+
/* OMAP3/4 non-CORE DPLL clkops */
const struct clk_hw_omap_ops clkhwops_omap3_dpll = {
.allow_idle = omap3_dpll_allow_idle,
diff --git a/drivers/clk/ti/gate.c b/drivers/clk/ti/gate.c
index 935b2de..2453b36 100644
--- a/drivers/clk/ti/gate.c
+++ b/drivers/clk/ti/gate.c
@@ -33,6 +33,7 @@
.init = &omap2_init_clk_clkdm,
.enable = &omap2_clkops_enable_clkdm,
.disable = &omap2_clkops_disable_clkdm,
+ .restore_context = clk_gate_restore_context,
};

const struct clk_ops omap_gate_clk_ops = {
@@ -40,6 +41,7 @@
.enable = &omap2_dflt_clk_enable,
.disable = &omap2_dflt_clk_disable,
.is_enabled = &omap2_dflt_clk_is_enabled,
+ .restore_context = clk_gate_restore_context,
};

static const struct clk_ops omap_gate_clk_hsdiv_restore_ops = {
@@ -47,6 +49,7 @@
.enable = &omap36xx_gate_clk_enable_with_hsdiv_restore,
.disable = &omap2_dflt_clk_disable,
.is_enabled = &omap2_dflt_clk_is_enabled,
+ .restore_context = clk_gate_restore_context,
};

/**
diff --git a/drivers/clk/ti/mux.c b/drivers/clk/ti/mux.c
index 69a4308..5749b2b 100644
--- a/drivers/clk/ti/mux.c
+++ b/drivers/clk/ti/mux.c
@@ -91,10 +91,39 @@ static int ti_clk_mux_set_parent(struct clk_hw *hw, u8 index)
return 0;
}

+/**
+ * clk_mux_save_context - Save the parent selcted in the mux
+ * @hw: pointer struct clk_hw
+ *
+ * Save the parent mux value.
+ */
+static int clk_mux_save_context(struct clk_hw *hw)
+{
+ struct clk_omap_mux *mux = to_clk_omap_mux(hw);
+
+ mux->saved_parent = ti_clk_mux_get_parent(hw);
+ return 0;
+}
+
+/**
+ * clk_mux_restore_context - Restore the parent in the mux
+ * @hw: pointer struct clk_hw
+ *
+ * Restore the saved parent mux value.
+ */
+static void clk_mux_restore_context(struct clk_hw *hw)
+{
+ struct clk_omap_mux *mux = to_clk_omap_mux(hw);
+
+ ti_clk_mux_set_parent(hw, mux->saved_parent);
+}
+
const struct clk_ops ti_clk_mux_ops = {
.get_parent = ti_clk_mux_get_parent,
.set_parent = ti_clk_mux_set_parent,
.determine_rate = __clk_mux_determine_rate,
+ .save_context = clk_mux_save_context,
+ .restore_context = clk_mux_restore_context,
};

static struct clk *_register_mux(struct device *dev, const char *name,
diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h
index a8faa38..c1b13bb 100644
--- a/include/linux/clk/ti.h
+++ b/include/linux/clk/ti.h
@@ -159,6 +159,7 @@ struct clk_hw_omap {
const char *clkdm_name;
struct clockdomain *clkdm;
const struct clk_hw_omap_ops *ops;
+ u32 context;
};

/*
@@ -293,6 +294,11 @@ struct ti_clk_features {

void ti_clk_setup_features(struct ti_clk_features *features);
const struct ti_clk_features *ti_clk_get_features(void);
+int omap3_noncore_dpll_save_context(struct clk_hw *hw);
+void omap3_noncore_dpll_restore_context(struct clk_hw *hw);
+
+int omap3_core_dpll_save_context(struct clk_hw *hw);
+void omap3_core_dpll_restore_context(struct clk_hw *hw);

extern const struct clk_hw_omap_ops clkhwops_omap2xxx_dpll;

--
1.9.1