clk: tegra: pll: Add logic for SS

Add some logic for Spread Spectrum control. It is used in conjuncture
with SDM fractional dividers. SSC has to be disabled when we configure
the divider settings.

Signed-off-by: Bill Huang <bilhuang@nvidia.com>
Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/clk/tegra/clk-pll.c

@@ -658,6 +658,26 @@ static void _update_pll_cpcon(struct tegra_clk_pll *pll,
 	pll_writel_misc(val, pll);
 }
 
+static void pll_clk_start_ss(struct tegra_clk_pll *pll)
+{
+	if (pll->params->defaults_set && pll->params->ssc_ctrl_reg) {
+		u32 val = pll_readl(pll->params->ssc_ctrl_reg, pll);
+
+		val |= pll->params->ssc_ctrl_en_mask;
+		pll_writel(val, pll->params->ssc_ctrl_reg, pll);
+	}
+}
+
+static void pll_clk_stop_ss(struct tegra_clk_pll *pll)
+{
+	if (pll->params->defaults_set && pll->params->ssc_ctrl_reg) {
+		u32 val = pll_readl(pll->params->ssc_ctrl_reg, pll);
+
+		val &= ~pll->params->ssc_ctrl_en_mask;
+		pll_writel(val, pll->params->ssc_ctrl_reg, pll);
+	}
+}
+
 static int _program_pll(struct clk_hw *hw, struct tegra_clk_pll_freq_table *cfg,
 			unsigned long rate)
 {
@@ -676,8 +696,10 @@ static int _program_pll(struct clk_hw *hw, struct tegra_clk_pll_freq_table *cfg,
 			return 0;
 	}
 
-	if (state)
+	if (state) {
+		pll_clk_stop_ss(pll);
 		_clk_pll_disable(hw);
+	}
 
 	if (!pll->params->defaults_set && pll->params->set_defaults)
 		pll->params->set_defaults(pll);
@@ -690,6 +712,7 @@ static int _program_pll(struct clk_hw *hw, struct tegra_clk_pll_freq_table *cfg,
 	if (state) {
 		_clk_pll_enable(hw);
 		ret = clk_pll_wait_for_lock(pll);
+		pll_clk_start_ss(pll);
 	}
 
 	return ret;

drivers/clk/tegra/clk.h

@@ -184,6 +184,8 @@ struct tegra_clk_pll;
  * @sdm_din_mask:		Mask of SDM divider bits
  * @sdm_ctrl_reg:		Register offset where SDM enable is
  * @sdm_ctrl_en_mask:		Mask of SDM enable bit
+ * @ssc_ctrl_reg:		Register offset where SSC settings are
+ * @ssc_ctrl_en_mask:		Mask of SSC enable bit
  * @aux_reg:			AUX register offset
  * @dyn_ramp_reg:		Dynamic ramp control register offset
  * @ext_misc_reg:		Miscellaneous control register offsets
@@ -262,6 +264,8 @@ struct tegra_clk_pll_params {
 	u32		sdm_din_mask;
 	u32		sdm_ctrl_reg;
 	u32		sdm_ctrl_en_mask;
+	u32		ssc_ctrl_reg;
+	u32		ssc_ctrl_en_mask;
 	u32		aux_reg;
 	u32		dyn_ramp_reg;
 	u32		ext_misc_reg[MAX_PLL_MISC_REG_COUNT];