[PATCH v5 17/21] clk: tegra: pll: Add logic for SS

From: Rhyland Klein
Date: Tue May 12 2015 - 13:28:31 EST


From: Bill Huang <bilhuang@xxxxxxxxxx>

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@xxxxxxxxxx>
---
v5:
- Reorderd Patch so set_defaults logic is present already

drivers/clk/tegra/clk-pll.c | 25 ++++++++++++++++++++++++-
drivers/clk/tegra/clk.h | 4 ++++
2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
index 36aa2a95fac0..727fedff824d 100644
--- a/drivers/clk/tegra/clk-pll.c
+++ b/drivers/clk/tegra/clk-pll.c
@@ -648,6 +648,26 @@ 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_en_mask) {
+ 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_en_mask) {
+ 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)
{
@@ -666,8 +686,10 @@ 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);
@@ -680,6 +702,7 @@ 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;
diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
index 38b4c95cfb2f..32ce32a056ca 100644
--- a/drivers/clk/tegra/clk.h
+++ b/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
@@ -251,6 +253,8 @@ 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];
--
1.7.9.5

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