[PATCH 10/13] clk: qcom: support for Huayra PLL

[Abhishek Sahu]

Following are the major differences in Huayra PLL

1. PLL Alpha Value is 16 bits
2. Depending on alpha_mode, the pll_alpha_val can be treated as
   M/N value or as a twoâs compliment number.
3. Huayra PLL supports PLL dynamic programming. User can change
   L_VAL, without having to go through the power on sequence.

Since the decoding of alpha val and dynamic programming are
completely different from other Alpha PLLâs so this patch
made adds separate functions for Huayra PLL.

Signed-off-by: Abhishek Sahu <absahu@xxxxxxxxxxxxxx>
---
 drivers/clk/qcom/clk-alpha-pll.c | 184 +++++++++++++++++++++++++++++++++++++++
 drivers/clk/qcom/clk-alpha-pll.h |   1 +
 2 files changed, 185 insertions(+)

diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
index bb35c60..4844e63 100644
--- a/drivers/clk/qcom/clk-alpha-pll.c
+++ b/drivers/clk/qcom/clk-alpha-pll.c
@@ -41,9 +41,17 @@
 # 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
 
+#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
+
 /*
  * Even though 40 bits are present, use only 32 for ease of calculation.
  */
@@ -585,6 +593,157 @@ static long alpha_pll_default_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 twoâs 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 twoâs 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);
+	u8 type = pll->pll_type;
+	u32 l, alpha = 0, ctl, alpha_m, alpha_n, off = pll->offset;
+
+	regmap_read(pll->clkr.regmap, off + pll_l(type), &l);
+	regmap_read(pll->clkr.regmap, off + pll_user_ctl(type), &ctl);
+
+	if (ctl & PLL_ALPHA_EN) {
+		regmap_read(pll->clkr.regmap, off + pll_alpha(type), &alpha);
+		/*
+		 * Depending upon alpha_mode, it can be treated as M/N value or
+		 * as a twoâs compliment number. When
+		 * alpha_mode=1 pll_alpha_val<15:8>=M & 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.
+		 *
+		 * alpha_mode=0, it is a twoâs compliment number in the range
+		 * of [-0.5, 0.5).
+		 *		Fout=FIN*(L+(alpha_val)/2^16),where alpha_val is
+		 * twoâs 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);
+	u8 type = pll->pll_type;
+	u32 l, a, ctl, cur_alpha = 0, off = pll->offset;
+
+	rate = alpha_huayra_pll_round_rate(rate, prate, &l, &a);
+
+	regmap_read(pll->clkr.regmap, off + pll_user_ctl(type), &ctl);
+
+	if (ctl & PLL_ALPHA_EN)
+		regmap_read(pll->clkr.regmap, off + pll_alpha(type),
+			    &cur_alpha);
+
+	/*
+	 * Huayra PLL supports PLL dynamic programming. User can change L_VAL,
+	 * without having to go through the power on sequence.
+	 */
+	if (clk_hw_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, off + pll_l(type), 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, off + pll_l(type), l);
+	regmap_write(pll->clkr.regmap, off + pll_alpha(type), a);
+
+	if (a == 0)
+		regmap_update_bits(pll->clkr.regmap, off + pll_user_ctl(type),
+				   PLL_ALPHA_EN, 0x0);
+	else
+		regmap_update_bits(pll->clkr.regmap, off + pll_user_ctl(type),
+				   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);
+}
+
 static int clk_alpha_pll_enable(struct clk_hw *hw)
 {
 	return pll_clk_ops(hw).enable(hw);
@@ -738,4 +897,29 @@ static int clk_alpha_pll_postdiv_set_rate(struct clk_hw *hw, unsigned long rate,
 			.set_rate = alpha_pll_default_set_rate,
 		},
 	},
+	[CLK_ALPHA_PLL_TYPE_HUAYRA] =  {
+		.reg_offsets = {
+			[PLL_L_VAL] = 0x04,
+			[PLL_ALPHA_VAL] = 0x08,
+			[PLL_USER_CTL] = 0x10,
+			[PLL_CONFIG_CTL] = 0x14,
+			[PLL_CONFIG_CTL_U] = 0x18,
+			[PLL_TEST_CTL] = 0x1c,
+			[PLL_TEST_CTL_U] = 0x20,
+			[PLL_STATUS] = 0x24,
+		},
+		.alpha_width = 16,
+		.flags = SUPPORTS_DYNAMIC_UPDATE | HAVE_64BIT_CONFIG_CTL,
+		.ops = {
+			.enable = alpha_pll_default_enable,
+			.disable = alpha_pll_default_disable,
+			.is_enabled = alpha_pll_default_is_enabled,
+			.hwfsm_enable = alpha_pll_default_hwfsm_enable,
+			.hwfsm_disable = alpha_pll_default_hwfsm_disable,
+			.hwfsm_is_enabled = alpha_pll_default_hwfsm_is_enabled,
+			.recalc_rate = alpha_pll_huayra_recalc_rate,
+			.round_rate = alpha_pll_huayra_round_rate,
+			.set_rate = alpha_pll_huayra_set_rate,
+		},
+	},
 };
diff --git a/drivers/clk/qcom/clk-alpha-pll.h b/drivers/clk/qcom/clk-alpha-pll.h
index 17aa27c..fed783e 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,
 };
 
-- 
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