clk: tegra: pll: Add Set_default logic

Add logic which (if specified for a pll) can verify that a PLL is set
to the proper default value and if not can set it. This can be
specified per PLL as each will have different default values.

Based on original work by Aleksandr Frid <afrid@nvidia.com>

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

@@ -662,13 +662,19 @@ static int _program_pll(struct clk_hw *hw, struct tegra_clk_pll_freq_table *cfg,
 			unsigned long rate)
 {
 	struct tegra_clk_pll *pll = to_clk_pll(hw);
+	struct tegra_clk_pll_freq_table old_cfg;
 	int state, ret = 0;
 
 	state = clk_pll_is_enabled(hw);
 
+	_get_pll_mnp(pll, &old_cfg);
+
 	if (state)
 		_clk_pll_disable(hw);
 
+	if (!pll->params->defaults_set && pll->params->set_defaults)
+		pll->params->set_defaults(pll);
+
 	_update_pll_mnp(pll, cfg);
 
 	if (pll->params->flags & TEGRA_PLL_HAS_CPCON)
@@ -1494,6 +1500,9 @@ static struct clk *_tegra_clk_register_pll(struct tegra_clk_pll *pll,
 			pll->params->calc_rate = _calc_rate;
 	}
 
+	if (pll->params->set_defaults)
+		pll->params->set_defaults(pll);
+
 	/* Data in .init is copied by clk_register(), so stack variable OK */
 	pll->hw.init = &init;
 
@@ -1604,7 +1613,6 @@ struct clk *tegra_clk_register_pllxc(const char *name, const char *parent_name,
 	struct tegra_clk_pll *pll;
 	struct clk *clk, *parent;
 	unsigned long parent_rate;
-	int err;
 	u32 val, val_iddq;
 
 	parent = __clk_lookup(parent_name);
@@ -1625,18 +1633,27 @@ struct clk *tegra_clk_register_pllxc(const char *name, const char *parent_name,
 		pll_params->vco_min = pll_params->adjust_vco(pll_params,
 							     parent_rate);
 
-	err = _setup_dynamic_ramp(pll_params, clk_base, parent_rate);
-	if (err)
-		return ERR_PTR(err);
+	/*
+	 * If the pll has a set_defaults callback, it will take care of
+	 * configuring dynamic ramping and setting IDDQ in that path.
+	 */
+	if (!pll_params->set_defaults) {
+		int err;
 
-	val = readl_relaxed(clk_base + pll_params->base_reg);
-	val_iddq = readl_relaxed(clk_base + pll_params->iddq_reg);
+		err = _setup_dynamic_ramp(pll_params, clk_base, parent_rate);
+		if (err)
+			return ERR_PTR(err);
 
-	if (val & PLL_BASE_ENABLE)
-		WARN_ON(val_iddq & BIT(pll_params->iddq_bit_idx));
-	else {
-		val_iddq |= BIT(pll_params->iddq_bit_idx);
-		writel_relaxed(val_iddq, clk_base + pll_params->iddq_reg);
+		val = readl_relaxed(clk_base + pll_params->base_reg);
+		val_iddq = readl_relaxed(clk_base + pll_params->iddq_reg);
+
+		if (val & PLL_BASE_ENABLE)
+			WARN_ON(val_iddq & BIT(pll_params->iddq_bit_idx));
+		else {
+			val_iddq |= BIT(pll_params->iddq_bit_idx);
+			writel_relaxed(val_iddq,
+				       clk_base + pll_params->iddq_reg);
+		}
 	}
 
 	pll = _tegra_init_pll(clk_base, pmc, pll_params, lock);

drivers/clk/tegra/clk.h

@@ -160,6 +160,8 @@ struct div_nmp {
 
 #define MAX_PLL_MISC_REG_COUNT	6
 
+struct tegra_clk_pll;
+
 /**
  * struct tegra_clk_pll_params - PLL parameters
  *
@@ -192,6 +194,7 @@ struct div_nmp {
  * @stepb_shift:		Dynamic ramp step B field shift
  * @lock_delay:			Delay in us if PLL lock is not used
  * @max_p:			maximum value for the p divider
+ * @defaults_set:		Boolean signaling all reg defaults for PLL set.
  * @pdiv_tohw:			mapping of p divider to register values
  * @div_nmp:			offsets and widths on n, m and p fields
  * @freq_table:			array of frequencies supported by PLL
@@ -204,6 +207,12 @@ struct div_nmp {
  *				rates (dividers and multipler) are calculated.
  * @adjust_vco:			Callback to adjust the programming range of the
  *				divider range (if SDM is present)
+ * @set_defaults:		Callback which will try to initialize PLL
+ *				registers to sane default values. This is first
+ *				tried during PLL registration, but if the PLL
+ *				is already enabled, it will be done the first
+ *				time the rate is changed while the PLL is
+ *				disabled.
  *
  * Flags:
  * TEGRA_PLL_USE_LOCK - This flag indicated to use lock bits for
@@ -261,6 +270,7 @@ struct tegra_clk_pll_params {
 	int		stepb_shift;
 	int		lock_delay;
 	int		max_p;
+	bool		defaults_set;
 	const struct pdiv_map *pdiv_tohw;
 	struct div_nmp	*div_nmp;
 	struct tegra_clk_pll_freq_table	*freq_table;
@@ -273,6 +283,7 @@ struct tegra_clk_pll_params {
 			unsigned long rate, unsigned long parent_rate);
 	unsigned long	(*adjust_vco)(struct tegra_clk_pll_params *pll_params,
 				unsigned long parent_rate);
+	void	(*set_defaults)(struct tegra_clk_pll *pll);
 };
 
 #define TEGRA_PLL_USE_LOCK BIT(0)