diff options
| -rw-r--r-- | drivers/clk/meson/Makefile | 2 | ||||
| -rw-r--r-- | drivers/clk/meson/clk-audio-divider.c | 144 | ||||
| -rw-r--r-- | drivers/clk/meson/clkc.h | 10 |
3 files changed, 155 insertions, 1 deletions
diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile index 349583405b7c..83b6d9d65aa1 100644 --- a/drivers/clk/meson/Makefile +++ b/drivers/clk/meson/Makefile @@ -2,6 +2,6 @@ # Makefile for Meson specific clk # -obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-pll.o clk-cpu.o clk-mpll.o +obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-pll.o clk-cpu.o clk-mpll.o clk-audio-divider.o obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o obj-$(CONFIG_COMMON_CLK_GXBB) += gxbb.o gxbb-aoclk.o diff --git a/drivers/clk/meson/clk-audio-divider.c b/drivers/clk/meson/clk-audio-divider.c new file mode 100644 index 000000000000..6c07db06642d --- /dev/null +++ b/drivers/clk/meson/clk-audio-divider.c @@ -0,0 +1,144 @@ +/* + * Copyright (c) 2017 AmLogic, Inc. + * Author: Jerome Brunet <jbrunet@baylibre.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/* + * i2s master clock divider: The algorithm of the generic clk-divider used with + * a very precise clock parent such as the mpll tends to select a low divider + * factor. This gives poor results with this particular divider, especially with + * high frequencies (> 100 MHz) + * + * This driver try to select the maximum possible divider with the rate the + * upstream clock can provide. + */ + +#include <linux/clk-provider.h> +#include "clkc.h" + +#define to_meson_clk_audio_divider(_hw) container_of(_hw, \ + struct meson_clk_audio_divider, hw) + +static int _div_round(unsigned long parent_rate, unsigned long rate, + unsigned long flags) +{ + if (flags & CLK_DIVIDER_ROUND_CLOSEST) + return DIV_ROUND_CLOSEST_ULL((u64)parent_rate, rate); + + return DIV_ROUND_UP_ULL((u64)parent_rate, rate); +} + +static int _get_val(unsigned long parent_rate, unsigned long rate) +{ + return DIV_ROUND_UP_ULL((u64)parent_rate, rate) - 1; +} + +static int _valid_divider(struct clk_hw *hw, int divider) +{ + struct meson_clk_audio_divider *adiv = + to_meson_clk_audio_divider(hw); + int max_divider; + u8 width; + + width = adiv->div.width; + max_divider = 1 << width; + + return clamp(divider, 1, max_divider); +} + +static unsigned long audio_divider_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct meson_clk_audio_divider *adiv = + to_meson_clk_audio_divider(hw); + struct parm *p; + unsigned long reg, divider; + + p = &adiv->div; + reg = readl(adiv->base + p->reg_off); + divider = PARM_GET(p->width, p->shift, reg) + 1; + + return DIV_ROUND_UP_ULL((u64)parent_rate, divider); +} + +static long audio_divider_round_rate(struct clk_hw *hw, + unsigned long rate, + unsigned long *parent_rate) +{ + struct meson_clk_audio_divider *adiv = + to_meson_clk_audio_divider(hw); + unsigned long max_prate; + int divider; + + if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) { + divider = _div_round(*parent_rate, rate, adiv->flags); + divider = _valid_divider(hw, divider); + return DIV_ROUND_UP_ULL((u64)*parent_rate, divider); + } + + /* Get the maximum parent rate */ + max_prate = clk_hw_round_rate(clk_hw_get_parent(hw), ULONG_MAX); + + /* Get the corresponding rounded down divider */ + divider = max_prate / rate; + divider = _valid_divider(hw, divider); + + /* Get actual rate of the parent */ + *parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw), + divider * rate); + + return DIV_ROUND_UP_ULL((u64)*parent_rate, divider); +} + +static int audio_divider_set_rate(struct clk_hw *hw, + unsigned long rate, + unsigned long parent_rate) +{ + struct meson_clk_audio_divider *adiv = + to_meson_clk_audio_divider(hw); + struct parm *p; + unsigned long reg, flags = 0; + int val; + + val = _get_val(parent_rate, rate); + + if (adiv->lock) + spin_lock_irqsave(adiv->lock, flags); + else + __acquire(adiv->lock); + + p = &adiv->div; + reg = readl(adiv->base + p->reg_off); + reg = PARM_SET(p->width, p->shift, reg, val); + writel(reg, adiv->base + p->reg_off); + + if (adiv->lock) + spin_unlock_irqrestore(adiv->lock, flags); + else + __release(adiv->lock); + + return 0; +} + +const struct clk_ops meson_clk_audio_divider_ro_ops = { + .recalc_rate = audio_divider_recalc_rate, + .round_rate = audio_divider_round_rate, +}; + +const struct clk_ops meson_clk_audio_divider_ops = { + .recalc_rate = audio_divider_recalc_rate, + .round_rate = audio_divider_round_rate, + .set_rate = audio_divider_set_rate, +}; diff --git a/drivers/clk/meson/clkc.h b/drivers/clk/meson/clkc.h index b0c9999d03de..d6feafe8bd6c 100644 --- a/drivers/clk/meson/clkc.h +++ b/drivers/clk/meson/clkc.h @@ -121,6 +121,14 @@ struct meson_clk_mpll { spinlock_t *lock; }; +struct meson_clk_audio_divider { + struct clk_hw hw; + void __iomem *base; + struct parm div; + u8 flags; + spinlock_t *lock; +}; + #define MESON_GATE(_name, _reg, _bit) \ struct clk_gate _name = { \ .reg = (void __iomem *) _reg, \ @@ -141,5 +149,7 @@ extern const struct clk_ops meson_clk_pll_ops; extern const struct clk_ops meson_clk_cpu_ops; 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_audio_divider_ro_ops; +extern const struct clk_ops meson_clk_audio_divider_ops; #endif /* __CLKC_H */ |