// SPDX-License-Identifier: GPL-2.0 /* * Copyright (c) 2015 Endless Mobile, Inc. * Author: Carlo Caione * * Copyright (c) 2018 Baylibre, SAS. * Author: Jerome Brunet */ /* * In the most basic form, a Meson PLL is composed as follows: * * PLL * +------------------------------+ * | | * in -----[ /N ]---[ *M ]---[ >>OD ]----->> out * | ^ ^ | * +------------------------------+ * | | * FREF VCO * * out = in * (m + frac / frac_max) / (n << sum(ods)) */ #include #include #include #include #include #include #include #include #include #include "clkc.h" static inline struct meson_clk_pll_data * meson_clk_pll_data(struct clk_regmap *clk) { return (struct meson_clk_pll_data *)clk->data; } static unsigned long __pll_params_to_rate(unsigned long parent_rate, const struct pll_rate_table *pllt, u16 frac, struct meson_clk_pll_data *pll) { u64 rate = (u64)parent_rate * pllt->m; unsigned int od = pllt->od + pllt->od2 + pllt->od3; if (frac && MESON_PARM_APPLICABLE(&pll->frac)) { u64 frac_rate = (u64)parent_rate * frac; rate += DIV_ROUND_UP_ULL(frac_rate, (1 << pll->frac.width)); } return DIV_ROUND_UP_ULL(rate, pllt->n << od); } static unsigned long meson_clk_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) { struct clk_regmap *clk = to_clk_regmap(hw); struct meson_clk_pll_data *pll = meson_clk_pll_data(clk); struct pll_rate_table pllt; u16 frac; pllt.n = meson_parm_read(clk->map, &pll->n); pllt.m = meson_parm_read(clk->map, &pll->m); pllt.od = meson_parm_read(clk->map, &pll->od); pllt.od2 = MESON_PARM_APPLICABLE(&pll->od2) ? meson_parm_read(clk->map, &pll->od2) : 0; pllt.od3 = MESON_PARM_APPLICABLE(&pll->od3) ? meson_parm_read(clk->map, &pll->od3) : 0; frac = MESON_PARM_APPLICABLE(&pll->frac) ? meson_parm_read(clk->map, &pll->frac) : 0; return __pll_params_to_rate(parent_rate, &pllt, frac, pll); } static u16 __pll_params_with_frac(unsigned long rate, unsigned long parent_rate, const struct pll_rate_table *pllt, struct meson_clk_pll_data *pll) { u16 frac_max = (1 << pll->frac.width); u64 val = (u64)rate * pllt->n; val <<= pllt->od + pllt->od2 + pllt->od3; if (pll->flags & CLK_MESON_PLL_ROUND_CLOSEST) val = DIV_ROUND_CLOSEST_ULL(val * frac_max, parent_rate); else val = div_u64(val * frac_max, parent_rate); val -= pllt->m * frac_max; return min((u16)val, (u16)(frac_max - 1)); } static const struct pll_rate_table * meson_clk_get_pll_settings(unsigned long rate, struct meson_clk_pll_data *pll) { const struct pll_rate_table *table = pll->table; unsigned int i = 0; if (!table) return NULL; /* Find the first table element exceeding rate */ while (table[i].rate && table[i].rate <= rate) i++; if (i != 0) { if (MESON_PARM_APPLICABLE(&pll->frac) || !(pll->flags & CLK_MESON_PLL_ROUND_CLOSEST) || (abs(rate - table[i - 1].rate) < abs(rate - table[i].rate))) i--; } return (struct pll_rate_table *)&table[i]; } static long meson_clk_pll_round_rate(struct clk_hw *hw, unsigned long rate, unsigned long *parent_rate) { struct clk_regmap *clk = to_clk_regmap(hw); struct meson_clk_pll_data *pll = meson_clk_pll_data(clk); const struct pll_rate_table *pllt = meson_clk_get_pll_settings(rate, pll); u16 frac; if (!pllt) return meson_clk_pll_recalc_rate(hw, *parent_rate); if (!MESON_PARM_APPLICABLE(&pll->frac) || rate == pllt->rate) return pllt->rate; /* * The rate provided by the setting is not an exact match, let's * try to improve the result using the fractional parameter */ frac = __pll_params_with_frac(rate, *parent_rate, pllt, pll); return __pll_params_to_rate(*parent_rate, pllt, frac, pll); } static int meson_clk_pll_wait_lock(struct clk_hw *hw) { struct clk_regmap *clk = to_clk_regmap(hw); struct meson_clk_pll_data *pll = meson_clk_pll_data(clk); int delay = 24000000; do { /* Is the clock locked now ? */ if (meson_parm_read(clk->map, &pll->l)) return 0; delay--; } while (delay > 0); return -ETIMEDOUT; } static void meson_clk_pll_init(struct clk_hw *hw) { struct clk_regmap *clk = to_clk_regmap(hw); struct meson_clk_pll_data *pll = meson_clk_pll_data(clk); if (pll->init_count) { meson_parm_write(clk->map, &pll->rst, 1); regmap_multi_reg_write(clk->map, pll->init_regs, pll->init_count); meson_parm_write(clk->map, &pll->rst, 0); } } static int meson_clk_pll_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate) { struct clk_regmap *clk = to_clk_regmap(hw); struct meson_clk_pll_data *pll = meson_clk_pll_data(clk); const struct pll_rate_table *pllt; unsigned long old_rate; u16 frac = 0; if (parent_rate == 0 || rate == 0) return -EINVAL; old_rate = clk_hw_get_rate(hw); pllt = meson_clk_get_pll_settings(rate, pll); if (!pllt) return -EINVAL; /* Put the pll in reset to write the params */ meson_parm_write(clk->map, &pll->rst, 1); meson_parm_write(clk->map, &pll->n, pllt->n); meson_parm_write(clk->map, &pll->m, pllt->m); meson_parm_write(clk->map, &pll->od, pllt->od); if (MESON_PARM_APPLICABLE(&pll->od2)) meson_parm_write(clk->map, &pll->od2, pllt->od2); if (MESON_PARM_APPLICABLE(&pll->od3)) meson_parm_write(clk->map, &pll->od3, pllt->od3); if (MESON_PARM_APPLICABLE(&pll->frac)) { frac = __pll_params_with_frac(rate, parent_rate, pllt, pll); meson_parm_write(clk->map, &pll->frac, frac); } /* make sure the reset is cleared at this point */ meson_parm_write(clk->map, &pll->rst, 0); if (meson_clk_pll_wait_lock(hw)) { pr_warn("%s: pll did not lock, trying to restore old rate %lu\n", __func__, old_rate); /* * FIXME: Do we really need/want this HACK ? * It looks unsafe. what happens if the clock gets into a * broken state and we can't lock back on the old_rate ? Looks * like an infinite recursion is possible */ meson_clk_pll_set_rate(hw, old_rate, parent_rate); } return 0; } const struct clk_ops meson_clk_pll_ops = { .init = meson_clk_pll_init, .recalc_rate = meson_clk_pll_recalc_rate, .round_rate = meson_clk_pll_round_rate, .set_rate = meson_clk_pll_set_rate, }; const struct clk_ops meson_clk_pll_ro_ops = { .recalc_rate = meson_clk_pll_recalc_rate, };