[PATCH v2 1/5] clk: samsung: clk-pll: Implement pll0822x PLL type

[Sam Protsenko]

pll0822x PLL is used in Exynos850 SoC for top-level integer PLLs. The
code was derived from very similar pll35xx type, with next differences:

1. Lock time for pll0822x is 150*P_DIV, when for pll35xx it's 270*P_DIV
2. It's not suggested in Exynos850 TRM that S_DIV change doesn't require
   performing PLL lock procedure (which is done in pll35xx
   implementation)

When defining pll0822x type, CON3 register offset should be provided as
a "con" parameter of PLL() macro, like this:

    PLL(pll_0822x, 0, "fout_shared0_pll", "oscclk",
        PLL_LOCKTIME_PLL_SHARED0, PLL_CON3_PLL_SHARED0,
        exynos850_shared0_pll_rates),

To define PLL rates table, one can use PLL_35XX_RATE() macro, e.g.:

    PLL_35XX_RATE(26 * MHZ, 1600 * MHZ, 800, 13, 0)

as it's completely appropriate for pl0822x type and there is no sense in
duplicating that.

If bit #1 (MANUAL_PLL_CTRL) is not set in CON1 register, it won't be
possible to set new rate, with next error showing in kernel log:

    Could not lock PLL fout_shared1_pll

That can happen for example if bootloader clears that bit beforehand.
PLL driver doesn't account for that, so if MANUAL_PLL_CTRL bit was
cleared, it's assumed it was done for a reason and it shouldn't be
possible to change that PLL's rate at all.

Signed-off-by: Sam Protsenko <semen.protsenko at linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski at canonical.com>
Acked-by: Chanwoo Choi <cw00.choi at samsung.com>
---
Changes in v2:
  - Added R-b tag by Krzysztof Kozlowski
  - Added Ack tag by Chanwoo Choi

 drivers/clk/samsung/clk-pll.c | 91 +++++++++++++++++++++++++++++++++++
 drivers/clk/samsung/clk-pll.h |  1 +
 2 files changed, 92 insertions(+)

diff --git a/drivers/clk/samsung/clk-pll.c b/drivers/clk/samsung/clk-pll.c
index 5873a9354b50..03131b149c0b 100644
--- a/drivers/clk/samsung/clk-pll.c
+++ b/drivers/clk/samsung/clk-pll.c
@@ -415,6 +415,89 @@ static const struct clk_ops samsung_pll36xx_clk_min_ops = {
 	.recalc_rate = samsung_pll36xx_recalc_rate,
 };
 
+/*
+ * PLL0822x Clock Type
+ */
+/* Maximum lock time can be 150 * PDIV cycles */
+#define PLL0822X_LOCK_FACTOR		(150)
+
+#define PLL0822X_MDIV_MASK		(0x3FF)
+#define PLL0822X_PDIV_MASK		(0x3F)
+#define PLL0822X_SDIV_MASK		(0x7)
+#define PLL0822X_MDIV_SHIFT		(16)
+#define PLL0822X_PDIV_SHIFT		(8)
+#define PLL0822X_SDIV_SHIFT		(0)
+#define PLL0822X_LOCK_STAT_SHIFT	(29)
+#define PLL0822X_ENABLE_SHIFT		(31)
+
+static unsigned long samsung_pll0822x_recalc_rate(struct clk_hw *hw,
+						  unsigned long parent_rate)
+{
+	struct samsung_clk_pll *pll = to_clk_pll(hw);
+	u32 mdiv, pdiv, sdiv, pll_con3;
+	u64 fvco = parent_rate;
+
+	pll_con3 = readl_relaxed(pll->con_reg);
+	mdiv = (pll_con3 >> PLL0822X_MDIV_SHIFT) & PLL0822X_MDIV_MASK;
+	pdiv = (pll_con3 >> PLL0822X_PDIV_SHIFT) & PLL0822X_PDIV_MASK;
+	sdiv = (pll_con3 >> PLL0822X_SDIV_SHIFT) & PLL0822X_SDIV_MASK;
+
+	fvco *= mdiv;
+	do_div(fvco, (pdiv << sdiv));
+
+	return (unsigned long)fvco;
+}
+
+static int samsung_pll0822x_set_rate(struct clk_hw *hw, unsigned long drate,
+				     unsigned long prate)
+{
+	const struct samsung_pll_rate_table *rate;
+	struct samsung_clk_pll *pll = to_clk_pll(hw);
+	u32 pll_con3;
+
+	/* Get required rate settings from table */
+	rate = samsung_get_pll_settings(pll, drate);
+	if (!rate) {
+		pr_err("%s: Invalid rate : %lu for pll clk %s\n", __func__,
+			drate, clk_hw_get_name(hw));
+		return -EINVAL;
+	}
+
+	/* Change PLL PMS values */
+	pll_con3 = readl_relaxed(pll->con_reg);
+	pll_con3 &= ~((PLL0822X_MDIV_MASK << PLL0822X_MDIV_SHIFT) |
+			(PLL0822X_PDIV_MASK << PLL0822X_PDIV_SHIFT) |
+			(PLL0822X_SDIV_MASK << PLL0822X_SDIV_SHIFT));
+	pll_con3 |= (rate->mdiv << PLL0822X_MDIV_SHIFT) |
+			(rate->pdiv << PLL0822X_PDIV_SHIFT) |
+			(rate->sdiv << PLL0822X_SDIV_SHIFT);
+
+	/* Set PLL lock time */
+	writel_relaxed(rate->pdiv * PLL0822X_LOCK_FACTOR,
+			pll->lock_reg);
+
+	/* Write PMS values */
+	writel_relaxed(pll_con3, pll->con_reg);
+
+	/* Wait for PLL lock if the PLL is enabled */
+	if (pll_con3 & BIT(pll->enable_offs))
+		return samsung_pll_lock_wait(pll, BIT(pll->lock_offs));
+
+	return 0;
+}
+
+static const struct clk_ops samsung_pll0822x_clk_ops = {
+	.recalc_rate = samsung_pll0822x_recalc_rate,
+	.round_rate = samsung_pll_round_rate,
+	.set_rate = samsung_pll0822x_set_rate,
+	.enable = samsung_pll3xxx_enable,
+	.disable = samsung_pll3xxx_disable,
+};
+
+static const struct clk_ops samsung_pll0822x_clk_min_ops = {
+	.recalc_rate = samsung_pll0822x_recalc_rate,
+};
+
 /*
  * PLL45xx Clock Type
  */
@@ -1296,6 +1379,14 @@ static void __init _samsung_clk_register_pll(struct samsung_clk_provider *ctx,
 		else
 			init.ops = &samsung_pll35xx_clk_ops;
 		break;
+	case pll_0822x:
+		pll->enable_offs = PLL0822X_ENABLE_SHIFT;
+		pll->lock_offs = PLL0822X_LOCK_STAT_SHIFT;
+		if (!pll->rate_table)
+			init.ops = &samsung_pll0822x_clk_min_ops;
+		else
+			init.ops = &samsung_pll0822x_clk_ops;
+		break;
 	case pll_4500:
 		init.ops = &samsung_pll45xx_clk_min_ops;
 		break;
diff --git a/drivers/clk/samsung/clk-pll.h b/drivers/clk/samsung/clk-pll.h
index 79e41c226b90..213e94a97f23 100644
--- a/drivers/clk/samsung/clk-pll.h
+++ b/drivers/clk/samsung/clk-pll.h
@@ -36,6 +36,7 @@ enum samsung_pll_type {
 	pll_1451x,
 	pll_1452x,
 	pll_1460x,
+	pll_0822x,
 };
 
 #define PLL_RATE(_fin, _m, _p, _s, _k, _ks) \
-- 
2.30.2