clk: ti: Add functions to save/restore clk context

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@ti.com>
Signed-off-by: Russ Dill <Russ.Dill@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Tero Kristo <t-kristo@ti.com>

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)

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,

drivers/clk/ti/dpll.c

@@ -39,6 +39,8 @@ static const struct clk_ops dpll_m4xen_ck_ops = {
 	.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 @@ static const struct clk_ops dpll_ck_ops = {
 	.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 @@ static const struct clk_ops dpll_no_gate_ck_ops = {
 	.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 = {};

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,

drivers/clk/ti/gate.c

@@ -33,6 +33,7 @@ static const struct clk_ops omap_gate_clkdm_clk_ops = {
 	.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 @@ const struct clk_ops omap_gate_clk_ops = {
 	.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 @@ static const struct clk_ops omap_gate_clk_hsdiv_restore_ops = {
 	.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,
 };
 
 /**

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,

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;
 };
 
 /*
@@ -294,6 +295,11 @@ 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;