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Date: Tue, 22 Jan 2019 10:25:15 +0100
From: Jerome Brunet <jbrunet@...libre.com>
To: Jianxin Pan <jianxin.pan@...ogic.com>,
Neil Armstrong <narmstrong@...libre.com>
Cc: Kevin Hilman <khilman@...libre.com>,
Carlo Caione <carlo@...one.org>,
Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...nel.org>, Rob Herring <robh@...nel.org>,
Miquel Raynal <miquel.raynal@...tlin.com>,
Boris Brezillon <boris.brezillon@...tlin.com>,
Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
Yixun Lan <yixun.lan@...ogic.com>,
Liang Yang <liang.yang@...ogic.com>,
Jian Hu <jian.hu@...ogic.com>,
Qiufang Dai <qiufang.dai@...ogic.com>,
Hanjie Lin <hanjie.lin@...ogic.com>,
Victor Wan <victor.wan@...ogic.com>, linux-clk@...r.kernel.org,
linux-amlogic@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org
Subject: Re: [PATCH v9 1/4] clk: meson: add one based divider support for
sclk divider
On Tue, 2019-01-08 at 21:50 +0800, Jianxin Pan wrote:
> When CLK_DIVIDER_ONE_BASED flag is set, the sclk divider will be:
> one based divider (div = val), and zero value gates the clock
>
> Signed-off-by: Jianxin Pan <jianxin.pan@...ogic.com>
> ---
> drivers/clk/meson/Makefile | 3 ++-
> drivers/clk/meson/clkc-audio.h | 8 ------
> drivers/clk/meson/clkc.h | 10 ++++++-
> drivers/clk/meson/sclk-div.c | 59 ++++++++++++++++++++++++++++-----------
> ---
> 4 files changed, 50 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
> index a849aa8..acd8694 100644
> --- a/drivers/clk/meson/Makefile
> +++ b/drivers/clk/meson/Makefile
> @@ -4,7 +4,8 @@
>
> 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-$(CONFIG_COMMON_CLK_AMLOGIC_AUDIO) += clk-triphase.o sclk-div.o
> +obj-$(CONFIG_COMMON_CLK_AMLOGIC) += sclk-div.o
> +obj-$(CONFIG_COMMON_CLK_AMLOGIC_AUDIO) += clk-triphase.o
> obj-$(CONFIG_COMMON_CLK_MESON_AO) += meson-aoclk.o
> obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o
> obj-$(CONFIG_COMMON_CLK_GXBB) += gxbb.o gxbb-aoclk.o gxbb-aoclk-
> 32k.o
> diff --git a/drivers/clk/meson/clkc-audio.h b/drivers/clk/meson/clkc-audio.h
> index 0a7c157..286ff12 100644
> --- a/drivers/clk/meson/clkc-audio.h
> +++ b/drivers/clk/meson/clkc-audio.h
> @@ -15,14 +15,6 @@ struct meson_clk_triphase_data {
> struct parm ph2;
> };
>
> -struct meson_sclk_div_data {
> - struct parm div;
> - struct parm hi;
> - unsigned int cached_div;
> - struct clk_duty cached_duty;
> -};
> -
> extern const struct clk_ops meson_clk_triphase_ops;
> -extern const struct clk_ops meson_sclk_div_ops;
>
> #endif /* __MESON_CLKC_AUDIO_H */
> diff --git a/drivers/clk/meson/clkc.h b/drivers/clk/meson/clkc.h
> index 6183b22..00b3320 100644
> --- a/drivers/clk/meson/clkc.h
> +++ b/drivers/clk/meson/clkc.h
> @@ -27,6 +27,14 @@ struct parm {
> u8 width;
> };
>
> +struct meson_sclk_div_data {
> + struct parm div;
> + struct parm hi;
> + unsigned int cached_div;
> + struct clk_duty cached_duty;
> + u8 flags;
> +};
> +
> static inline unsigned int meson_parm_read(struct regmap *map, struct parm
> *p)
> {
> unsigned int val;
> @@ -118,10 +126,10 @@ struct clk_regmap _name = {
> \
> 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_sclk_div_ops;
>
> struct clk_hw *meson_clk_hw_register_input(struct device *dev,
> const char *of_name,
> const char *clk_name,
> unsigned long flags);
> -
> #endif /* __CLKC_H */
> diff --git a/drivers/clk/meson/sclk-div.c b/drivers/clk/meson/sclk-div.c
> index bc64019..a6c425b 100644
> --- a/drivers/clk/meson/sclk-div.c
> +++ b/drivers/clk/meson/sclk-div.c
> @@ -4,42 +4,60 @@
> * Author: Jerome Brunet <jbrunet@...libre.com>
> *
> * Sample clock generator divider:
> - * This HW divider gates with value 0 but is otherwise a zero based
> divider:
> + * This HW divider gates with value 0
> *
> * val >= 1
> - * divider = val + 1
> + * divider = val + 1 if ONE_BASED is not set, otherwise divider = val.
> *
> * The duty cycle may also be set for the LR clock variant. The duty cycle
> * ratio is:
> *
> * hi = [0 - val]
> - * duty_cycle = (1 + hi) / (1 + val)
> + * duty_cycle = (1 + hi) / (1 + val) if ONE_BASED is not set, otherwise:
> + * duty_cycle = hi / (1 + val)
> */
>
> -#include "clkc-audio.h"
> +#include "clkc.h"
>
> -static inline struct meson_sclk_div_data *
> -meson_sclk_div_data(struct clk_regmap *clk)
> +static inline int get_reg(int val, unsigned char flag)
s/get_reg/sclk_get_reg
> {
> - return (struct meson_sclk_div_data *)clk->data;
> + WARN_ON(val < 1);
I don't think this WARN is justified, especially since you are using this
function to set the hi value.
> + if ((flag & CLK_DIVIDER_ONE_BASED) || !val)
I don't like that you make a dependency on the generic divider just for this.
Please make your own flag like MESON_SCLK_ONE_BASED
> + return val;
> + else
> + return val - 1;
> +}
> +
> +static inline int get_value(int reg, unsigned char flag)
s/get_value/sclk_get_divider
> +{
> + if (flag & CLK_DIVIDER_ONE_BASED)
> + return reg;
> + else
> + return reg + 1;
> }
>
> -static int sclk_div_maxval(struct meson_sclk_div_data *sclk)
> +static inline struct meson_sclk_div_data *
> +meson_sclk_div_data(struct clk_regmap *clk)
> {
> - return (1 << sclk->div.width) - 1;
> + return (struct meson_sclk_div_data *)clk->data;
> }
>
> static int sclk_div_maxdiv(struct meson_sclk_div_data *sclk)
> {
> - return sclk_div_maxval(sclk) + 1;
> + unsigned int reg = clk_div_mask(sclk->div.width);
same here, leave the generic divider alone.
`(1 << sclk->div.width) - 1` was fine to get max register value.
> +
> + return get_value(reg, sclk->flags);
> }
>
> static int sclk_div_getdiv(struct clk_hw *hw, unsigned long rate,
> unsigned long prate, int maxdiv)
> {
> int div = DIV_ROUND_CLOSEST_ULL((u64)prate, rate);
> + struct clk_regmap *clk = to_clk_regmap(hw);
> + struct meson_sclk_div_data *sclk = meson_sclk_div_data(clk);
> + int mindiv = get_value(1, sclk->flags);
maxdiv is provided as a param while mindiv is computed inside this function.
let's be coherent and pick one approach.
>
> - return clamp(div, 2, maxdiv);
> + return clamp(div, mindiv, maxdiv);
> }
>
> static int sclk_div_bestdiv(struct clk_hw *hw, unsigned long rate,
> @@ -47,7 +65,7 @@ static int sclk_div_bestdiv(struct clk_hw *hw, unsigned
> long rate,
> struct meson_sclk_div_data *sclk)
> {
> struct clk_hw *parent = clk_hw_get_parent(hw);
> - int bestdiv = 0, i;
> + int bestdiv = 0, i, mindiv;
> unsigned long maxdiv, now, parent_now;
> unsigned long best = 0, best_parent = 0;
>
> @@ -64,8 +82,9 @@ static int sclk_div_bestdiv(struct clk_hw *hw, unsigned
> long rate,
> * unsigned long in rate * i below
> */
> maxdiv = min(ULONG_MAX / rate, maxdiv);
> + mindiv = get_value(1, sclk->flags);
>
> - for (i = 2; i <= maxdiv; i++) {
> + for (i = mindiv; i <= maxdiv; i++) {
> /*
> * It's the most ideal case if the requested rate can be
> * divided from parent clock without needing to change
> @@ -111,10 +130,7 @@ static void sclk_apply_ratio(struct clk_regmap *clk,
> sclk->cached_duty.num,
> sclk->cached_duty.den);
>
> - if (hi)
> - hi -= 1;
> -
> - meson_parm_write(clk->map, &sclk->hi, hi);
> + meson_parm_write(clk->map, &sclk->hi, get_reg(hi, sclk->flags));
> }
>
> static int sclk_div_set_duty_cycle(struct clk_hw *hw,
> @@ -145,7 +161,7 @@ static int sclk_div_get_duty_cycle(struct clk_hw *hw,
> }
>
> hi = meson_parm_read(clk->map, &sclk->hi);
> - duty->num = hi + 1;
> + duty->num = get_value(hi, sclk->flags);
> duty->den = sclk->cached_div;
> return 0;
> }
> @@ -153,10 +169,13 @@ static int sclk_div_get_duty_cycle(struct clk_hw *hw,
> static void sclk_apply_divider(struct clk_regmap *clk,
> struct meson_sclk_div_data *sclk)
> {
> + unsigned int div;
> +
> if (MESON_PARM_APPLICABLE(&sclk->hi))
> sclk_apply_ratio(clk, sclk);
>
> - meson_parm_write(clk->map, &sclk->div, sclk->cached_div - 1);
> + div = get_reg(sclk->cached_div, sclk->flags);
> + meson_parm_write(clk->map, &sclk->div, div);
> }
>
> static int sclk_div_set_rate(struct clk_hw *hw, unsigned long rate,
> @@ -224,7 +243,7 @@ static void sclk_div_init(struct clk_hw *hw)
> if (!val)
> sclk->cached_div = sclk_div_maxdiv(sclk);
> else
> - sclk->cached_div = val + 1;
> + sclk->cached_div = get_value(val, sclk->flags);
>
> sclk_div_get_duty_cycle(hw, &sclk->cached_duty);
> }
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