Re: [PATCH RESEND v7 4/4] clk: meson: add one based divider support for sclk divider
From: Jerome Brunet <jbrunet@baylibre.com>
Date: 2018-12-11 17:17:04
Also in:
linux-amlogic, linux-clk, lkml
On Tue, 2018-12-11 at 00:04 +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 <redacted> --- drivers/clk/meson/clkc-audio.h | 1 + drivers/clk/meson/sclk-div.c | 28 ++++++++++++++++++---------- 2 files changed, 19 insertions(+), 10 deletions(-)
Such a patch should be done earlier in the series, at least before using sclk in your controller, otherwise thing will be broken in between In general, I would prefer if you had added two helper function to deal with the translation between register value and divider value. Only these function should care about CLK_DIVIDER_ONE_BASED, the rest should just call them. This, we will be able to deal the with HI (duty cycle) part as well, which you completly skiped. I know your device does not have this, but still the code has to make sense.
quoted hunk ↗ jump to hunk
diff --git a/drivers/clk/meson/clkc-audio.h b/drivers/clk/meson/clkc-audio.h index 0a7c157..9bd6ced 100644 --- a/drivers/clk/meson/clkc-audio.h +++ b/drivers/clk/meson/clkc-audio.h@@ -20,6 +20,7 @@ struct meson_sclk_div_data { struct parm hi; unsigned int cached_div; struct clk_duty cached_duty; + u8 flags; }; extern const struct clk_ops meson_clk_triphase_ops;diff --git a/drivers/clk/meson/sclk-div.c b/drivers/clk/meson/sclk-div.c index bc64019..d98707b 100644 --- a/drivers/clk/meson/sclk-div.c +++ b/drivers/clk/meson/sclk-div.c@@ -24,22 +24,23 @@ return (struct meson_sclk_div_data *)clk->data; } -static int sclk_div_maxval(struct meson_sclk_div_data *sclk) -{ - return (1 << sclk->div.width) - 1; -} - static int sclk_div_maxdiv(struct meson_sclk_div_data *sclk) { - return sclk_div_maxval(sclk) + 1; + if (sclk->flags & CLK_DIVIDER_ONE_BASED) + return clk_div_mask(sclk->div.width); + else + return clk_div_mask(sclk->div.width) + 1;
seems over complicated. why no call clk_div_mask just once, and add 1 if necessary ?
}
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 = (sclk->flags & CLK_DIVIDER_ONE_BASED) ? 1 : 2;This is why I want helpers, don't like this above
quoted hunk ↗ jump to hunk
- return clamp(div, 2, maxdiv); + return clamp(div, mindiv, maxdiv); } static int sclk_div_bestdiv(struct clk_hw *hw, unsigned long rate,@@ -47,7 +48,7 @@ static int sclk_div_bestdiv(struct clk_hw *hw, unsignedlong 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 +65,9 @@ static int sclk_div_bestdiv(struct clk_hw *hw, unsignedlong rate, * unsigned long in rate * i below */ maxdiv = min(ULONG_MAX / rate, maxdiv); + mindiv = (sclk->flags & CLK_DIVIDER_ONE_BASED) ? 1 : 2; - 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@@ -153,10 +155,14 @@ 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 = (sclk->flags & CLK_DIVIDER_ONE_BASED) ? + sclk->cached_div : (sclk->cached_div - 1);
helpers again.
quoted hunk ↗ jump to hunk
+ meson_parm_write(clk->map, &sclk->div, div); } static int sclk_div_set_rate(struct clk_hw *hw, unsigned long rate,@@ -223,6 +229,8 @@ static void sclk_div_init(struct clk_hw *hw) /* if the divider is initially disabled, assume max */ if (!val) sclk->cached_div = sclk_div_maxdiv(sclk); + else if (sclk->flags & CLK_DIVIDER_ONE_BASED) + sclk->cached_div = val; else sclk->cached_div = val + 1;
same ...
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