[PATCH 2/6] clk: samsung: clk-pll: Implement pll0822x PLL type

Sam Protsenko
2021-09-14T15:56:17Z

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@linaro.org>
---
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