Re: [PATCH 08/16] clk: sunxi-ng: Add M-factor clock support

Chen-Yu Tsai
2016-05-21T17:09:09Z

Hi,

On Mon, May 9, 2016 at 4:01 AM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:
> Introduce support for clocks that divide by a linear factor.

I think we can have just one implementation for single divide factor
(either P or M)
clocks, using the CCF divider helpers. Even the divider table clock
could be merged
in.

>
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
> drivers/clk/sunxi-ng/Makefile | 1 +
> drivers/clk/sunxi-ng/ccu_m.c | 135 ++++++++++++++++++++++++++++++++++++++++++
> drivers/clk/sunxi-ng/ccu_m.h | 101 +++++++++++++++++++++++++++++++
> 3 files changed, 237 insertions(+)
> create mode 100644 drivers/clk/sunxi-ng/ccu_m.c
> create mode 100644 drivers/clk/sunxi-ng/ccu_m.h
>
> diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
> index a47a3bbdf285..f41de901c607 100644
> --- a/drivers/clk/sunxi-ng/Makefile
> +++ b/drivers/clk/sunxi-ng/Makefile
> @@ -4,5 +4,6 @@ obj-y += ccu_reset.o
> obj-y += ccu_div_table.o
> obj-y += ccu_fixed_factor.o
> obj-y += ccu_gate.o
> +obj-y += ccu_m.o
> obj-y += ccu_mux.o
> obj-y += ccu_phase.o
> diff --git a/drivers/clk/sunxi-ng/ccu_m.c b/drivers/clk/sunxi-ng/ccu_m.c
> new file mode 100644
> index 000000000000..424eb6da0d5b
> --- /dev/null
> +++ b/drivers/clk/sunxi-ng/ccu_m.c
> @@ -0,0 +1,135 @@
> +/*
> + * Copyright (C) 2016 Maxime Ripard
> + * Maxime Ripard <maxime.ripard@free-electrons.com>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + */
> +
> +#include <linux/clk-provider.h>
> +
> +#include "ccu_gate.h"
> +#include "ccu_m.h"
> +#include "ccu_mux.h"
> +
> +static void ccu_m_find_best(unsigned long parent, unsigned long rate,
> + unsigned int max_m, unsigned int *m)
> +{
> + unsigned int _m = parent / rate;
> +
> + if (_m > max_m)
> + _m = max_m;
> +
> + *m = _m;
> +}

This can go.

> +
> +static unsigned long ccu_m_round_rate(struct ccu_mux_internal *mux,
> + unsigned long parent_rate,
> + unsigned long rate,
> + void *data)
> +{
> + struct ccu_m *cm = data;
> + unsigned int m;
> +
> + ccu_m_find_best(parent_rate, rate, 1 << cm->m.width, &m);
> +
> + return parent_rate / m;

Use divider_round_rate() helper instead.

> +}
> +
> +
> +static void ccu_m_disable(struct clk_hw *hw)
> +{
> + struct ccu_m *cm = hw_to_ccu_m(hw);
> +
> + return ccu_gate_helper_disable(&cm->common, cm->enable);
> +}
> +
> +static int ccu_m_enable(struct clk_hw *hw)
> +{
> + struct ccu_m *cm = hw_to_ccu_m(hw);
> +
> + return ccu_gate_helper_enable(&cm->common, cm->enable);
> +}
> +
> +static int ccu_m_is_enabled(struct clk_hw *hw)
> +{
> + struct ccu_m *cm = hw_to_ccu_m(hw);
> +
> + return ccu_gate_helper_is_enabled(&cm->common, cm->enable);
> +}
> +
> +static unsigned long ccu_m_recalc_rate(struct clk_hw *hw,
> + unsigned long parent_rate)
> +{
> + struct ccu_m *cm = hw_to_ccu_m(hw);
> + unsigned long m;
> + u32 reg;
> +
> + reg = readl(cm->common.base + cm->common.reg);
> +
> + m = reg >> cm->m.shift;
> + m &= (1 << cm->m.width) - 1;
> +
> + return parent_rate / (m + 1);

Use divider_recalc_rate() helper.

> +}
> +
> +static int ccu_m_determine_rate(struct clk_hw *hw,
> + struct clk_rate_request *req)
> +{
> + struct ccu_m *cm = hw_to_ccu_m(hw);
> +
> + return ccu_mux_helper_determine_rate(&cm->common, &cm->mux,
> + req, ccu_m_round_rate, cm);
> +}
> +
> +static int ccu_m_set_rate(struct clk_hw *hw, unsigned long rate,
> + unsigned long parent_rate)
> +{
> + struct ccu_m *cm = hw_to_ccu_m(hw);
> + unsigned long flags;
> + unsigned int m;
> + u32 reg;
> +
> + ccu_m_find_best(parent_rate, rate, 1 << cm->m.width, &m);

Use divider_get_val() helper.

> +
> + spin_lock_irqsave(cm->common.lock, flags);
> +
> + reg = readl(cm->common.base + cm->common.reg);
> + reg &= ((1 << cm->m.width) - 1) << cm->m.shift;
> +
> + writel(reg | ((m - 1) << cm->m.shift),
> + cm->common.base + cm->common.reg);
> +
> + spin_unlock_irqrestore(cm->common.lock, flags);
> +
> + return 0;
> +}
> +
> +static u8 ccu_m_get_parent(struct clk_hw *hw)
> +{
> + struct ccu_m *cm = hw_to_ccu_m(hw);
> +
> + return ccu_mux_helper_get_parent(&cm->common, &cm->mux);
> +}
> +
> +static int ccu_m_set_parent(struct clk_hw *hw, u8 index)
> +{
> + struct ccu_m *cm = hw_to_ccu_m(hw);
> +
> + return ccu_mux_helper_set_parent(&cm->common, &cm->mux, index);
> +}
> +
> +const struct clk_ops ccu_m_ops = {
> + .disable = ccu_m_disable,
> + .enable = ccu_m_enable,
> + .is_enabled = ccu_m_is_enabled,
> +
> + .get_parent = ccu_m_get_parent,
> + .set_parent = ccu_m_set_parent,
> +
> + .determine_rate = ccu_m_determine_rate,
> + .recalc_rate = ccu_m_recalc_rate,
> + .set_rate = ccu_m_set_rate,
> +};
> diff --git a/drivers/clk/sunxi-ng/ccu_m.h b/drivers/clk/sunxi-ng/ccu_m.h
> new file mode 100644
> index 000000000000..625c0a7cef43
> --- /dev/null
> +++ b/drivers/clk/sunxi-ng/ccu_m.h
> @@ -0,0 +1,101 @@
> +/*
> + * Copyright (c) 2016 Maxime Ripard. All rights reserved.
> + *
> + * This software is licensed under the terms of the GNU General Public
> + * License version 2, as published by the Free Software Foundation, and
> + * may be copied, distributed, and modified under those terms.
> + *
> + * This program is distributed in the hope that 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.
> + */
> +
> +#ifndef _CCU_M_H_
> +#define _CCU_M_H_
> +
> +#include <linux/clk-provider.h>
> +
> +#include "ccu_common.h"
> +#include "ccu_factor.h"
> +#include "ccu_mux.h"
> +
> +struct ccu_m {
> + u32 enable;

Add a field for divider flags, such as CLK_DIVIDER_ONE_BASED and
CLK_DIVIDER_POWER_OF_TWO. With these we can merge P & M factor clocks,
and also be able to handle M factors starting from both 1 and 0.

Also add a field for divider tables to merge the divider table clock.

> +
> + struct ccu_factor m;
> + struct ccu_mux_internal mux;
> + struct ccu_common common;
> +};
> +
> +#define SUNXI_CCU_M(_struct, _name, _parent, _reg, _mshift, _mwidth, \
> + _flags) \
> + struct ccu_m _struct = { \
> + .m = SUNXI_CLK_FACTOR(_mshift, _mwidth), \
> + .common = { \
> + .reg = _reg, \
> + .hw.init = SUNXI_HW_INIT(_name, \
> + _parent, \
> + &ccu_m_ops, \
> + _flags), \
> + }, \
> + }
> +
> +#define SUNXI_CCU_M_WITH_GATE(_struct, _name, _parent, _reg, \
> + _mshift, _mwidth, _gate, \
> + _flags) \
> + struct ccu_m _struct = { \
> + .enable = _gate, \
> + .m = SUNXI_CLK_FACTOR(_mshift, _mwidth), \
> + .common = { \
> + .reg = _reg, \
> + .features = CCU_FEATURE_GATE, \
> + .hw.init = SUNXI_HW_INIT(_name, \
> + _parent, \
> + &ccu_m_ops, \
> + _flags), \
> + }, \
> + }
> +
> +#define SUNXI_CCU_M_WITH_MUX(_struct, _name, _parents, _reg, \
> + _mshift, _mwidth, _muxshift, _muxwidth, \
> + _flags) \
> + struct ccu_m _struct = { \
> + .m = SUNXI_CLK_FACTOR(_mshift, _mwidth), \
> + .mux = SUNXI_CLK_MUX(_muxshift, _muxwidth), \
> + .common = { \
> + .reg = _reg, \
> + .hw.init = SUNXI_HW_INIT_PARENTS(_name, \
> + _parents, \
> + &ccu_m_ops, \
> + _flags), \
> + }, \
> + }

Maybe you could use the full macro below to simplify the above 3, with
the unused fields set to 0?

Regards
ChenYu

> +
> +#define SUNXI_CCU_M_WITH_MUX_GATE(_struct, _name, _parents, _reg, \
> + _mshift, _mwidth, _muxshift, _muxwidth, \
> + _gate, _flags) \
> + struct ccu_m _struct = { \
> + .enable = _gate, \
> + .m = SUNXI_CLK_FACTOR(_mshift, _mwidth), \
> + .mux = SUNXI_CLK_MUX(_muxshift, _muxwidth), \
> + .common = { \
> + .reg = _reg, \
> + .features = CCU_FEATURE_GATE, \
> + .hw.init = SUNXI_HW_INIT_PARENTS(_name, \
> + _parents, \
> + &ccu_m_ops, \
> + _flags), \
> + }, \
> + }
> +
> +static inline struct ccu_m *hw_to_ccu_m(struct clk_hw *hw)
> +{
> + struct ccu_common *common = hw_to_ccu_common(hw);
> +
> + return container_of(common, struct ccu_m, common);
> +}
> +
> +extern const struct clk_ops ccu_m_ops;
> +
> +#endif /* _CCU_M_H_ */
> --
> 2.8.2
>