diff options
Diffstat (limited to 'drivers/clk/meson/clk-mpll.c')
| -rw-r--r-- | drivers/clk/meson/clk-mpll.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/drivers/clk/meson/clk-mpll.c b/drivers/clk/meson/clk-mpll.c new file mode 100644 index 0000000000..20255e129b --- /dev/null +++ b/drivers/clk/meson/clk-mpll.c @@ -0,0 +1,180 @@ +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) +/* + * Copyright (c) 2016 AmLogic, Inc. + * Author: Michael Turquette <mturquette@baylibre.com> + */ + +/* + * MultiPhase Locked Loops are outputs from a PLL with additional frequency + * scaling capabilities. MPLL rates are calculated as: + * + * f(N2_integer, SDM_IN ) = 2.0G/(N2_integer + SDM_IN/16384) + */ + +#include <linux/clk-provider.h> +#include <linux/module.h> +#include <linux/spinlock.h> + +#include "clk-regmap.h" +#include "clk-mpll.h" + +#define SDM_DEN 16384 +#define N2_MIN 4 +#define N2_MAX 511 + +static inline struct meson_clk_mpll_data * +meson_clk_mpll_data(struct clk_regmap *clk) +{ + return (struct meson_clk_mpll_data *)clk->data; +} + +static long rate_from_params(unsigned long parent_rate, + unsigned int sdm, + unsigned int n2) +{ + unsigned long divisor = (SDM_DEN * n2) + sdm; + + if (n2 < N2_MIN) + return -EINVAL; + + return DIV_ROUND_UP_ULL((u64)parent_rate * SDM_DEN, divisor); +} + +static void params_from_rate(unsigned long requested_rate, + unsigned long parent_rate, + unsigned int *sdm, + unsigned int *n2, + u8 flags) +{ + uint64_t div = parent_rate; + uint64_t frac = do_div(div, requested_rate); + + frac *= SDM_DEN; + + if (flags & CLK_MESON_MPLL_ROUND_CLOSEST) + *sdm = DIV_ROUND_CLOSEST_ULL(frac, requested_rate); + else + *sdm = DIV_ROUND_UP_ULL(frac, requested_rate); + + if (*sdm == SDM_DEN) { + *sdm = 0; + div += 1; + } + + if (div < N2_MIN) { + *n2 = N2_MIN; + *sdm = 0; + } else if (div > N2_MAX) { + *n2 = N2_MAX; + *sdm = SDM_DEN - 1; + } else { + *n2 = div; + } +} + +static unsigned long mpll_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk); + unsigned int sdm, n2; + long rate; + + sdm = meson_parm_read(clk->map, &mpll->sdm); + n2 = meson_parm_read(clk->map, &mpll->n2); + + rate = rate_from_params(parent_rate, sdm, n2); + return rate < 0 ? 0 : rate; +} + +static int mpll_determine_rate(struct clk_hw *hw, struct clk_rate_request *req) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk); + unsigned int sdm, n2; + long rate; + + params_from_rate(req->rate, req->best_parent_rate, &sdm, &n2, + mpll->flags); + + rate = rate_from_params(req->best_parent_rate, sdm, n2); + if (rate < 0) + return rate; + + req->rate = rate; + return 0; +} + +static int mpll_set_rate(struct clk_hw *hw, + unsigned long rate, + unsigned long parent_rate) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk); + unsigned int sdm, n2; + unsigned long flags = 0; + + params_from_rate(rate, parent_rate, &sdm, &n2, mpll->flags); + + if (mpll->lock) + spin_lock_irqsave(mpll->lock, flags); + else + __acquire(mpll->lock); + + /* Set the fractional part */ + meson_parm_write(clk->map, &mpll->sdm, sdm); + + /* Set the integer divider part */ + meson_parm_write(clk->map, &mpll->n2, n2); + + if (mpll->lock) + spin_unlock_irqrestore(mpll->lock, flags); + else + __release(mpll->lock); + + return 0; +} + +static int mpll_init(struct clk_hw *hw) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk); + + if (mpll->init_count) + regmap_multi_reg_write(clk->map, mpll->init_regs, + mpll->init_count); + + /* Enable the fractional part */ + meson_parm_write(clk->map, &mpll->sdm_en, 1); + + /* Set spread spectrum if possible */ + if (MESON_PARM_APPLICABLE(&mpll->ssen)) { + unsigned int ss = + mpll->flags & CLK_MESON_MPLL_SPREAD_SPECTRUM ? 1 : 0; + meson_parm_write(clk->map, &mpll->ssen, ss); + } + + /* Set the magic misc bit if required */ + if (MESON_PARM_APPLICABLE(&mpll->misc)) + meson_parm_write(clk->map, &mpll->misc, 1); + + return 0; +} + +const struct clk_ops meson_clk_mpll_ro_ops = { + .recalc_rate = mpll_recalc_rate, + .determine_rate = mpll_determine_rate, +}; +EXPORT_SYMBOL_GPL(meson_clk_mpll_ro_ops); + +const struct clk_ops meson_clk_mpll_ops = { + .recalc_rate = mpll_recalc_rate, + .determine_rate = mpll_determine_rate, + .set_rate = mpll_set_rate, + .init = mpll_init, +}; +EXPORT_SYMBOL_GPL(meson_clk_mpll_ops); + +MODULE_DESCRIPTION("Amlogic MPLL driver"); +MODULE_AUTHOR("Michael Turquette <mturquette@baylibre.com>"); +MODULE_LICENSE("GPL v2"); |