From a8d552a63857c73c6f0ea28dc8a70df10764b820 Mon Sep 17 00:00:00 2001 From: Jerome Brunet Date: Fri, 21 Dec 2018 17:02:37 +0100 Subject: [PATCH] clk: meson: add dual divider clock driver Add the dual divider driver. This special divider make a weighted average between 2 dividers to reach fractional divider values. Signed-off-by: Jerome Brunet Acked-by: Neil Armstrong Signed-off-by: Neil Armstrong Link: https://lkml.kernel.org/r/20181221160239.26265-4-jbrunet@baylibre.com --- drivers/clk/meson/Makefile | 2 +- drivers/clk/meson/clk-dualdiv.c | 130 ++++++++++++++++++++++++++++++++ drivers/clk/meson/clkc.h | 19 +++++ 3 files changed, 150 insertions(+), 1 deletion(-) create mode 100644 drivers/clk/meson/clk-dualdiv.c diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile index a849aa809825..f1fcafc046d5 100644 --- a/drivers/clk/meson/Makefile +++ b/drivers/clk/meson/Makefile @@ -3,7 +3,7 @@ # obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-pll.o clk-mpll.o clk-phase.o vid-pll-div.o -obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-input.o +obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-input.o clk-dualdiv.o obj-$(CONFIG_COMMON_CLK_AMLOGIC_AUDIO) += clk-triphase.o sclk-div.o obj-$(CONFIG_COMMON_CLK_MESON_AO) += meson-aoclk.o obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o diff --git a/drivers/clk/meson/clk-dualdiv.c b/drivers/clk/meson/clk-dualdiv.c new file mode 100644 index 000000000000..4d9e161de627 --- /dev/null +++ b/drivers/clk/meson/clk-dualdiv.c @@ -0,0 +1,130 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2017 BayLibre, SAS + * Author: Neil Armstrong + * Author: Jerome Brunet + */ + +/* + * The AO Domain embeds a dual/divider to generate a more precise + * 32,768KHz clock for low-power suspend mode and CEC. + * ______ ______ + * | | | | + * | Div1 |-| Cnt1 | + * /|______| |______|\ + * -| ______ ______ X--> Out + * \| | | |/ + * | Div2 |-| Cnt2 | + * |______| |______| + * + * The dividing can be switched to single or dual, with a counter + * for each divider to set when the switching is done. + */ + +#include +#include "clkc.h" + +static inline struct meson_clk_dualdiv_data * +meson_clk_dualdiv_data(struct clk_regmap *clk) +{ + return (struct meson_clk_dualdiv_data *)clk->data; +} + +static unsigned long +__dualdiv_param_to_rate(unsigned long parent_rate, + const struct meson_clk_dualdiv_param *p) +{ + if (!p->dual) + return DIV_ROUND_CLOSEST(parent_rate, p->n1); + + return DIV_ROUND_CLOSEST(parent_rate * (p->m1 + p->m2), + p->n1 * p->m1 + p->n2 * p->m2); +} + +static unsigned long meson_clk_dualdiv_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk); + struct meson_clk_dualdiv_param setting; + + setting.dual = meson_parm_read(clk->map, &dualdiv->dual); + setting.n1 = meson_parm_read(clk->map, &dualdiv->n1) + 1; + setting.m1 = meson_parm_read(clk->map, &dualdiv->m1) + 1; + setting.n2 = meson_parm_read(clk->map, &dualdiv->n2) + 1; + setting.m2 = meson_parm_read(clk->map, &dualdiv->m2) + 1; + + return __dualdiv_param_to_rate(parent_rate, &setting); +} + +static const struct meson_clk_dualdiv_param * +__dualdiv_get_setting(unsigned long rate, unsigned long parent_rate, + struct meson_clk_dualdiv_data *dualdiv) +{ + const struct meson_clk_dualdiv_param *table = dualdiv->table; + unsigned long best = 0, now = 0; + unsigned int i, best_i = 0; + + if (!table) + return NULL; + + for (i = 0; table[i].n1; i++) { + now = __dualdiv_param_to_rate(parent_rate, &table[i]); + + /* If we get an exact match, don't bother any further */ + if (now == rate) { + return &table[i]; + } else if (abs(now - rate) < abs(best - rate)) { + best = now; + best_i = i; + } + } + + return (struct meson_clk_dualdiv_param *)&table[best_i]; +} + +static long meson_clk_dualdiv_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk); + const struct meson_clk_dualdiv_param *setting = + __dualdiv_get_setting(rate, *parent_rate, dualdiv); + + if (!setting) + return meson_clk_dualdiv_recalc_rate(hw, *parent_rate); + + return __dualdiv_param_to_rate(*parent_rate, setting); +} + +static int meson_clk_dualdiv_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_regmap *clk = to_clk_regmap(hw); + struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk); + const struct meson_clk_dualdiv_param *setting = + __dualdiv_get_setting(rate, parent_rate, dualdiv); + + if (!setting) + return -EINVAL; + + meson_parm_write(clk->map, &dualdiv->dual, setting->dual); + meson_parm_write(clk->map, &dualdiv->n1, setting->n1 - 1); + meson_parm_write(clk->map, &dualdiv->m1, setting->m1 - 1); + meson_parm_write(clk->map, &dualdiv->n2, setting->n2 - 1); + meson_parm_write(clk->map, &dualdiv->m2, setting->m2 - 1); + + return 0; +} + +const struct clk_ops meson_clk_dualdiv_ops = { + .recalc_rate = meson_clk_dualdiv_recalc_rate, + .round_rate = meson_clk_dualdiv_round_rate, + .set_rate = meson_clk_dualdiv_set_rate, +}; +EXPORT_SYMBOL_GPL(meson_clk_dualdiv_ops); + +const struct clk_ops meson_clk_dualdiv_ro_ops = { + .recalc_rate = meson_clk_dualdiv_recalc_rate, +}; +EXPORT_SYMBOL_GPL(meson_clk_dualdiv_ro_ops); diff --git a/drivers/clk/meson/clkc.h b/drivers/clk/meson/clkc.h index 6183b22c4bf2..e3cd442db739 100644 --- a/drivers/clk/meson/clkc.h +++ b/drivers/clk/meson/clkc.h @@ -110,6 +110,23 @@ struct clk_regmap _name = { \ }, \ }; +struct meson_clk_dualdiv_param { + unsigned int n1; + unsigned int n2; + unsigned int m1; + unsigned int m2; + unsigned int dual; +}; + +struct meson_clk_dualdiv_data { + struct parm n1; + struct parm n2; + struct parm m1; + struct parm m2; + struct parm dual; + const struct meson_clk_dualdiv_param *table; +}; + /* clk_ops */ extern const struct clk_ops meson_clk_pll_ro_ops; extern const struct clk_ops meson_clk_pll_ops; @@ -118,6 +135,8 @@ extern const struct clk_ops meson_clk_mpll_ro_ops; extern const struct clk_ops meson_clk_mpll_ops; extern const struct clk_ops meson_clk_phase_ops; extern const struct clk_ops meson_vid_pll_div_ro_ops; +extern const struct clk_ops meson_clk_dualdiv_ops; +extern const struct clk_ops meson_clk_dualdiv_ro_ops; struct clk_hw *meson_clk_hw_register_input(struct device *dev, const char *of_name,