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>

1 files changed, 24 insertions, 1 deletions

diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
index 8901004025e7..7ef08861c35d 100644
--- a/drivers/clk/tegra/clk-pll.c
+++ b/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;