ARM: OMAP2+: clock: fix clkoutx2 with CLK_SET_RATE_PARENT

If CLK_SET_RATE_PARENT is set for a clkoutx2 clock, calling
clk_set_rate() on the clock "skips" the x2 multiplier as there are no
set_rate and round_rate functions defined for the clkoutx2.

This results in getting double the requested clock rates, breaking the
display on omap3430 based devices. This got broken when
d0f58bd3bb and related patches were merged
for v3.14, as omapdss driver now relies more on the clk-framework and
CLK_SET_RATE_PARENT.

This patch implements set_rate and round_rate for clkoutx2.

Tested on OMAP3430, OMAP3630, OMAP4460.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>

arch/arm/mach-omap2/cclock3xxx_data.c

@@ -433,7 +433,9 @@ static const struct clk_ops dpll4_m5x2_ck_ops = {
 	.enable		= &omap2_dflt_clk_enable,
 	.disable	= &omap2_dflt_clk_disable,
 	.is_enabled	= &omap2_dflt_clk_is_enabled,
+	.set_rate	= &omap3_clkoutx2_set_rate,
 	.recalc_rate	= &omap3_clkoutx2_recalc,
+	.round_rate	= &omap3_clkoutx2_round_rate,
 };
 
 static const struct clk_ops dpll4_m5x2_ck_3630_ops = {

arch/arm/mach-omap2/dpll3xxx.c

@@ -623,25 +623,12 @@ void omap3_dpll_deny_idle(struct clk_hw_omap *clk)
 
 /* Clock control for DPLL outputs */
 
-/**
- * omap3_clkoutx2_recalc - recalculate DPLL X2 output virtual clock rate
- * @clk: DPLL output struct clk
- *
- * Using parent clock DPLL data, look up DPLL state.  If locked, set our
- * rate to the dpll_clk * 2; otherwise, just use dpll_clk.
- */
-unsigned long omap3_clkoutx2_recalc(struct clk_hw *hw,
-				    unsigned long parent_rate)
+/* Find the parent DPLL for the given clkoutx2 clock */
+static struct clk_hw_omap *omap3_find_clkoutx2_dpll(struct clk_hw *hw)
 {
-	const struct dpll_data *dd;
-	unsigned long rate;
-	u32 v;
 	struct clk_hw_omap *pclk = NULL;
 	struct clk *parent;
 
-	if (!parent_rate)
-		return 0;
-
 	/* Walk up the parents of clk, looking for a DPLL */
 	do {
 		do {
@@ -656,9 +643,35 @@ unsigned long omap3_clkoutx2_recalc(struct clk_hw *hw,
 	/* clk does not have a DPLL as a parent?  error in the clock data */
 	if (!pclk) {
 		WARN_ON(1);
-		return 0;
+		return NULL;
 	}
 
+	return pclk;
+}
+
+/**
+ * omap3_clkoutx2_recalc - recalculate DPLL X2 output virtual clock rate
+ * @clk: DPLL output struct clk
+ *
+ * Using parent clock DPLL data, look up DPLL state.  If locked, set our
+ * rate to the dpll_clk * 2; otherwise, just use dpll_clk.
+ */
+unsigned long omap3_clkoutx2_recalc(struct clk_hw *hw,
+				    unsigned long parent_rate)
+{
+	const struct dpll_data *dd;
+	unsigned long rate;
+	u32 v;
+	struct clk_hw_omap *pclk = NULL;
+
+	if (!parent_rate)
+		return 0;
+
+	pclk = omap3_find_clkoutx2_dpll(hw);
+
+	if (!pclk)
+		return 0;
+
 	dd = pclk->dpll_data;
 
 	WARN_ON(!dd->enable_mask);
@@ -672,6 +685,55 @@ unsigned long omap3_clkoutx2_recalc(struct clk_hw *hw,
 	return rate;
 }
 
+int omap3_clkoutx2_set_rate(struct clk_hw *hw, unsigned long rate,
+					unsigned long parent_rate)
+{
+	return 0;
+}
+
+long omap3_clkoutx2_round_rate(struct clk_hw *hw, unsigned long rate,
+		unsigned long *prate)
+{
+	const struct dpll_data *dd;
+	u32 v;
+	struct clk_hw_omap *pclk = NULL;
+
+	if (!*prate)
+		return 0;
+
+	pclk = omap3_find_clkoutx2_dpll(hw);
+
+	if (!pclk)
+		return 0;
+
+	dd = pclk->dpll_data;
+
+	/* TYPE J does not have a clkoutx2 */
+	if (dd->flags & DPLL_J_TYPE) {
+		*prate = __clk_round_rate(__clk_get_parent(pclk->hw.clk), rate);
+		return *prate;
+	}
+
+	WARN_ON(!dd->enable_mask);
+
+	v = omap2_clk_readl(pclk, dd->control_reg) & dd->enable_mask;
+	v >>= __ffs(dd->enable_mask);
+
+	/* If in bypass, the rate is fixed to the bypass rate*/
+	if (v != OMAP3XXX_EN_DPLL_LOCKED)
+		return *prate;
+
+	if (__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT) {
+		unsigned long best_parent;
+
+		best_parent = (rate / 2);
+		*prate = __clk_round_rate(__clk_get_parent(hw->clk),
+				best_parent);
+	}
+
+	return *prate * 2;
+}
+
 /* OMAP3/4 non-CORE DPLL clkops */
 const struct clk_hw_omap_ops clkhwops_omap3_dpll = {
 	.allow_idle	= omap3_dpll_allow_idle,

include/linux/clk/ti.h

@@ -245,6 +245,10 @@ long omap2_dpll_round_rate(struct clk_hw *hw, unsigned long target_rate,
 void omap2_init_clk_clkdm(struct clk_hw *clk);
 unsigned long omap3_clkoutx2_recalc(struct clk_hw *hw,
 				    unsigned long parent_rate);
+int omap3_clkoutx2_set_rate(struct clk_hw *hw, unsigned long rate,
+					unsigned long parent_rate);
+long omap3_clkoutx2_round_rate(struct clk_hw *hw, unsigned long rate,
+		unsigned long *prate);
 int omap2_clkops_enable_clkdm(struct clk_hw *hw);
 void omap2_clkops_disable_clkdm(struct clk_hw *hw);
 int omap2_clk_disable_autoidle_all(void);