clk: qcom: support Huayra type Alpha PLL

The Huayra type Alpha PLL  has a 16 bit alpha value, and
depending on the alpha_mode, the alpha value can be treated as
M/N value or as a two’s compliment number. This PLL supports
dynamic programming.

Since the decoding of alpha val and dynamic programming are
completely different from other Alpha PLLs we add separate
functions for Huayra PLLs.

Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

2 files changed, 189 insertions, 5 deletions

diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
index 2a4b0c9f5c4d..6860f5b1db88 100644
--- a/drivers/clk/qcom/clk-alpha-pll.c
+++ b/drivers/clk/qcom/clk-alpha-pll.c
@@ -47,6 +47,7 @@
 # define PLL_POST_DIV_SHIFT	8
 # define PLL_POST_DIV_MASK	0xf
 # define PLL_ALPHA_EN		BIT(24)
+# define PLL_ALPHA_MODE		BIT(25)
 # define PLL_VCO_SHIFT		20
 # define PLL_VCO_MASK		0x3
 
@@ -70,6 +71,16 @@ const u8 clk_alpha_pll_regs[][PLL_OFF_MAX_REGS] = {
 		[PLL_OFF_TEST_CTL_U] = 0x20,
 		[PLL_OFF_STATUS] = 0x24,
 	},
+	[CLK_ALPHA_PLL_TYPE_HUAYRA] =  {
+		[PLL_OFF_L_VAL] = 0x04,
+		[PLL_OFF_ALPHA_VAL] = 0x08,
+		[PLL_OFF_USER_CTL] = 0x10,
+		[PLL_OFF_CONFIG_CTL] = 0x14,
+		[PLL_OFF_CONFIG_CTL_U] = 0x18,
+		[PLL_OFF_TEST_CTL] = 0x1c,
+		[PLL_OFF_TEST_CTL_U] = 0x20,
+		[PLL_OFF_STATUS] = 0x24,
+	},
 };
 EXPORT_SYMBOL_GPL(clk_alpha_pll_regs);
 
@@ -81,6 +92,13 @@ EXPORT_SYMBOL_GPL(clk_alpha_pll_regs);
 #define ALPHA_BITWIDTH		32U
 #define ALPHA_SHIFT(w)		min(w, ALPHA_BITWIDTH)
 
+#define PLL_HUAYRA_M_WIDTH		8
+#define PLL_HUAYRA_M_SHIFT		8
+#define PLL_HUAYRA_M_MASK		0xff
+#define PLL_HUAYRA_N_SHIFT		0
+#define PLL_HUAYRA_N_MASK		0xff
+#define PLL_HUAYRA_ALPHA_WIDTH		16
+
 #define pll_alpha_width(p)					\
 		((PLL_ALPHA_VAL_U(p) - PLL_ALPHA_VAL(p) == 4) ?	\
 				 ALPHA_REG_BITWIDTH : ALPHA_REG_16BIT_WIDTH)
@@ -473,7 +491,7 @@ static int __clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 
 	rate = alpha_pll_round_rate(rate, prate, &l, &a, alpha_width);
 	vco = alpha_pll_find_vco(pll, rate);
-	if (!vco) {
+	if (pll->vco_table && !vco) {
 		pr_err("alpha pll not in a valid vco range\n");
 		return -EINVAL;
 	}
@@ -488,9 +506,11 @@ static int __clk_alpha_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 
 	regmap_write(pll->clkr.regmap, PLL_ALPHA_VAL(pll), a);
 
-	regmap_update_bits(pll->clkr.regmap, PLL_USER_CTL(pll),
-			   PLL_VCO_MASK << PLL_VCO_SHIFT,
-			   vco->val << PLL_VCO_SHIFT);
+	if (vco) {
+		regmap_update_bits(pll->clkr.regmap, PLL_USER_CTL(pll),
+				   PLL_VCO_MASK << PLL_VCO_SHIFT,
+				   vco->val << PLL_VCO_SHIFT);
+	}
 
 	regmap_update_bits(pll->clkr.regmap, PLL_USER_CTL(pll),
 			   PLL_ALPHA_EN, PLL_ALPHA_EN);
@@ -521,7 +541,7 @@ static long clk_alpha_pll_round_rate(struct clk_hw *hw, unsigned long rate,
 	unsigned long min_freq, max_freq;
 
 	rate = alpha_pll_round_rate(rate, *prate, &l, &a, alpha_width);
-	if (alpha_pll_find_vco(pll, rate))
+	if (!pll->vco_table || alpha_pll_find_vco(pll, rate))
 		return rate;
 
 	min_freq = pll->vco_table[0].min_freq;
@@ -530,6 +550,158 @@ static long clk_alpha_pll_round_rate(struct clk_hw *hw, unsigned long rate,
 	return clamp(rate, min_freq, max_freq);
 }
 
+static unsigned long
+alpha_huayra_pll_calc_rate(u64 prate, u32 l, u32 a)
+{
+	/*
+	 * a contains 16 bit alpha_val in two’s compliment number in the range
+	 * of [-0.5, 0.5).
+	 */
+	if (a >= BIT(PLL_HUAYRA_ALPHA_WIDTH - 1))
+		l -= 1;
+
+	return (prate * l) + (prate * a >> PLL_HUAYRA_ALPHA_WIDTH);
+}
+
+static unsigned long
+alpha_huayra_pll_round_rate(unsigned long rate, unsigned long prate,
+			    u32 *l, u32 *a)
+{
+	u64 remainder;
+	u64 quotient;
+
+	quotient = rate;
+	remainder = do_div(quotient, prate);
+	*l = quotient;
+
+	if (!remainder) {
+		*a = 0;
+		return rate;
+	}
+
+	quotient = remainder << PLL_HUAYRA_ALPHA_WIDTH;
+	remainder = do_div(quotient, prate);
+
+	if (remainder)
+		quotient++;
+
+	/*
+	 * alpha_val should be in two’s compliment number in the range
+	 * of [-0.5, 0.5) so if quotient >= 0.5 then increment the l value
+	 * since alpha value will be subtracted in this case.
+	 */
+	if (quotient >= BIT(PLL_HUAYRA_ALPHA_WIDTH - 1))
+		*l += 1;
+
+	*a = quotient;
+	return alpha_huayra_pll_calc_rate(prate, *l, *a);
+}
+
+static unsigned long
+alpha_pll_huayra_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+	u64 rate = parent_rate, tmp;
+	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
+	u32 l, alpha = 0, ctl, alpha_m, alpha_n;
+
+	regmap_read(pll->clkr.regmap, PLL_L_VAL(pll), &l);
+	regmap_read(pll->clkr.regmap, PLL_USER_CTL(pll), &ctl);
+
+	if (ctl & PLL_ALPHA_EN) {
+		regmap_read(pll->clkr.regmap, PLL_ALPHA_VAL(pll), &alpha);
+		/*
+		 * Depending upon alpha_mode, it can be treated as M/N value or
+		 * as a two’s compliment number. When alpha_mode=1,
+		 * pll_alpha_val<15:8>=M and pll_apla_val<7:0>=N
+		 *
+		 *		Fout=FIN*(L+(M/N))
+		 *
+		 * M is a signed number (-128 to 127) and N is unsigned
+		 * (0 to 255). M/N has to be within +/-0.5.
+		 *
+		 * When alpha_mode=0, it is a two’s compliment number in the
+		 * range [-0.5, 0.5).
+		 *
+		 *		Fout=FIN*(L+(alpha_val)/2^16)
+		 *
+		 * where alpha_val is two’s compliment number.
+		 */
+		if (!(ctl & PLL_ALPHA_MODE))
+			return alpha_huayra_pll_calc_rate(rate, l, alpha);
+
+		alpha_m = alpha >> PLL_HUAYRA_M_SHIFT & PLL_HUAYRA_M_MASK;
+		alpha_n = alpha >> PLL_HUAYRA_N_SHIFT & PLL_HUAYRA_N_MASK;
+
+		rate *= l;
+		tmp = parent_rate;
+		if (alpha_m >= BIT(PLL_HUAYRA_M_WIDTH - 1)) {
+			alpha_m = BIT(PLL_HUAYRA_M_WIDTH) - alpha_m;
+			tmp *= alpha_m;
+			do_div(tmp, alpha_n);
+			rate -= tmp;
+		} else {
+			tmp *= alpha_m;
+			do_div(tmp, alpha_n);
+			rate += tmp;
+		}
+
+		return rate;
+	}
+
+	return alpha_huayra_pll_calc_rate(rate, l, alpha);
+}
+
+static int alpha_pll_huayra_set_rate(struct clk_hw *hw, unsigned long rate,
+				     unsigned long prate)
+{
+	struct clk_alpha_pll *pll = to_clk_alpha_pll(hw);
+	u32 l, a, ctl, cur_alpha = 0;
+
+	rate = alpha_huayra_pll_round_rate(rate, prate, &l, &a);
+
+	regmap_read(pll->clkr.regmap, PLL_USER_CTL(pll), &ctl);
+
+	if (ctl & PLL_ALPHA_EN)
+		regmap_read(pll->clkr.regmap, PLL_ALPHA_VAL(pll), &cur_alpha);
+
+	/*
+	 * Huayra PLL supports PLL dynamic programming. User can change L_VAL,
+	 * without having to go through the power on sequence.
+	 */
+	if (clk_alpha_pll_is_enabled(hw)) {
+		if (cur_alpha != a) {
+			pr_err("clock needs to be gated %s\n",
+			       clk_hw_get_name(hw));
+			return -EBUSY;
+		}
+
+		regmap_write(pll->clkr.regmap, PLL_L_VAL(pll), l);
+		/* Ensure that the write above goes to detect L val change. */
+		mb();
+		return wait_for_pll_enable_lock(pll);
+	}
+
+	regmap_write(pll->clkr.regmap, PLL_L_VAL(pll), l);
+	regmap_write(pll->clkr.regmap, PLL_ALPHA_VAL(pll), a);
+
+	if (a == 0)
+		regmap_update_bits(pll->clkr.regmap, PLL_USER_CTL(pll),
+				   PLL_ALPHA_EN, 0x0);
+	else
+		regmap_update_bits(pll->clkr.regmap, PLL_USER_CTL(pll),
+				   PLL_ALPHA_EN | PLL_ALPHA_MODE, PLL_ALPHA_EN);
+
+	return 0;
+}
+
+static long alpha_pll_huayra_round_rate(struct clk_hw *hw, unsigned long rate,
+					unsigned long *prate)
+{
+	u32 l, a;
+
+	return alpha_huayra_pll_round_rate(rate, *prate, &l, &a);
+}
+
 const struct clk_ops clk_alpha_pll_ops = {
 	.enable = clk_alpha_pll_enable,
 	.disable = clk_alpha_pll_disable,
@@ -540,6 +712,16 @@ const struct clk_ops clk_alpha_pll_ops = {
 };
 EXPORT_SYMBOL_GPL(clk_alpha_pll_ops);
 
+const struct clk_ops clk_alpha_pll_huayra_ops = {
+	.enable = clk_alpha_pll_enable,
+	.disable = clk_alpha_pll_disable,
+	.is_enabled = clk_alpha_pll_is_enabled,
+	.recalc_rate = alpha_pll_huayra_recalc_rate,
+	.round_rate = alpha_pll_huayra_round_rate,
+	.set_rate = alpha_pll_huayra_set_rate,
+};
+EXPORT_SYMBOL_GPL(clk_alpha_pll_huayra_ops);
+
 const struct clk_ops clk_alpha_pll_hwfsm_ops = {
 	.enable = clk_alpha_pll_hwfsm_enable,
 	.disable = clk_alpha_pll_hwfsm_disable,
diff --git a/drivers/clk/qcom/clk-alpha-pll.h b/drivers/clk/qcom/clk-alpha-pll.h
index 82fef8f1c9af..667e9069d086 100644
--- a/drivers/clk/qcom/clk-alpha-pll.h
+++ b/drivers/clk/qcom/clk-alpha-pll.h
@@ -20,6 +20,7 @@
 /* Alpha PLL types */
 enum {
 	CLK_ALPHA_PLL_TYPE_DEFAULT,
+	CLK_ALPHA_PLL_TYPE_HUAYRA,
 	CLK_ALPHA_PLL_TYPE_MAX,
 };
 
@@ -104,6 +105,7 @@ struct alpha_pll_config {
 extern const struct clk_ops clk_alpha_pll_ops;
 extern const struct clk_ops clk_alpha_pll_hwfsm_ops;
 extern const struct clk_ops clk_alpha_pll_postdiv_ops;
+extern const struct clk_ops clk_alpha_pll_huayra_ops;
 
 void clk_alpha_pll_configure(struct clk_alpha_pll *pll, struct regmap *regmap,
 			     const struct alpha_pll_config *config);