| Message ID | 1391012648-12481-3-git-send-email-maxime.coquelin@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Quoting Maxime COQUELIN (2014-01-29 08:24:07) > In some cases, we want to be able to round the divider to the closest one, > instead than rounding up. > > This patch adds a new CLK_DIVIDER_ROUND_CLOSEST flag to specify the divider > has to round to closest div, keeping rounding up as de default behaviour. I've taken patch #2 and #3 into clk-next for 3.16. Thanks! Mike > > Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com> > --- > drivers/clk/clk-divider.c | 69 ++++++++++++++++++++++++++++++++++++++++-- > include/linux/clk-provider.h | 3 ++ > 2 files changed, 70 insertions(+), 2 deletions(-) > > diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c > index 2137d58..1eaa5d8 100644 > --- a/drivers/clk/clk-divider.c > +++ b/drivers/clk/clk-divider.c > @@ -43,6 +43,17 @@ static unsigned int _get_table_maxdiv(const struct clk_div_table *table) > return maxdiv; > } > > +static unsigned int _get_table_mindiv(const struct clk_div_table *table) > +{ > + unsigned int mindiv = UINT_MAX; > + const struct clk_div_table *clkt; > + > + for (clkt = table; clkt->div; clkt++) > + if (clkt->div < mindiv) > + mindiv = clkt->div; > + return mindiv; > +} > + > static unsigned int _get_maxdiv(struct clk_divider *divider) > { > if (divider->flags & CLK_DIVIDER_ONE_BASED) > @@ -162,6 +173,24 @@ static int _round_up_table(const struct clk_div_table *table, int div) > return up; > } > > +static int _round_down_table(const struct clk_div_table *table, int div) > +{ > + const struct clk_div_table *clkt; > + int down = _get_table_mindiv(table); > + > + for (clkt = table; clkt->div; clkt++) { > + if (clkt->div == div) > + return clkt->div; > + else if (clkt->div > div) > + continue; > + > + if ((div - clkt->div) < (div - down)) > + down = clkt->div; > + } > + > + return down; > +} > + > static int _div_round_up(struct clk_divider *divider, > unsigned long parent_rate, unsigned long rate) > { > @@ -175,6 +204,42 @@ static int _div_round_up(struct clk_divider *divider, > return div; > } > > +static int _div_round_closest(struct clk_divider *divider, > + unsigned long parent_rate, unsigned long rate) > +{ > + int up, down, div; > + > + up = down = div = DIV_ROUND_CLOSEST(parent_rate, rate); > + > + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) { > + up = __roundup_pow_of_two(div); > + down = __rounddown_pow_of_two(div); > + } else if (divider->table) { > + up = _round_up_table(divider->table, div); > + down = _round_down_table(divider->table, div); > + } > + > + return (up - div) <= (div - down) ? up : down; > +} > + > +static int _div_round(struct clk_divider *divider, unsigned long parent_rate, > + unsigned long rate) > +{ > + if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST) > + return _div_round_closest(divider, parent_rate, rate); > + > + return _div_round_up(divider, parent_rate, rate); > +} > + > +static bool _is_best_div(struct clk_divider *divider, > + int rate, int now, int best) > +{ > + if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST) > + return abs(rate - now) < abs(rate - best); > + > + return now <= rate && now > best; > +} > + > static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, > unsigned long *best_parent_rate) > { > @@ -190,7 +255,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, > > if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) { > parent_rate = *best_parent_rate; > - bestdiv = _div_round_up(divider, parent_rate, rate); > + bestdiv = _div_round(divider, parent_rate, rate); > bestdiv = bestdiv == 0 ? 1 : bestdiv; > bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv; > return bestdiv; > @@ -217,7 +282,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, > parent_rate = __clk_round_rate(__clk_get_parent(hw->clk), > MULT_ROUND_UP(rate, i)); > now = parent_rate / i; > - if (now <= rate && now > best) { > + if (_is_best_div(divider, rate, now, best)) { > bestdiv = i; > best = now; > *best_parent_rate = parent_rate; > diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h > index 7e59253..595f0ba 100644 > --- a/include/linux/clk-provider.h > +++ b/include/linux/clk-provider.h > @@ -275,6 +275,8 @@ struct clk_div_table { > * of this register, and mask of divider bits are in higher 16-bit of this > * register. While setting the divider bits, higher 16-bit should also be > * updated to indicate changing divider bits. > + * CLK_DIVIDER_ROUND_CLOSEST - Makes the best calculated divider to be rounded > + * to the closest integer instead of the up one. > */ > struct clk_divider { > struct clk_hw hw; > @@ -290,6 +292,7 @@ struct clk_divider { > #define CLK_DIVIDER_POWER_OF_TWO BIT(1) > #define CLK_DIVIDER_ALLOW_ZERO BIT(2) > #define CLK_DIVIDER_HIWORD_MASK BIT(3) > +#define CLK_DIVIDER_ROUND_CLOSEST BIT(4) > > extern const struct clk_ops clk_divider_ops; > struct clk *clk_register_divider(struct device *dev, const char *name, > -- > 1.7.9.5 >
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c index 2137d58..1eaa5d8 100644 --- a/drivers/clk/clk-divider.c +++ b/drivers/clk/clk-divider.c @@ -43,6 +43,17 @@ static unsigned int _get_table_maxdiv(const struct clk_div_table *table) return maxdiv; } +static unsigned int _get_table_mindiv(const struct clk_div_table *table) +{ + unsigned int mindiv = UINT_MAX; + const struct clk_div_table *clkt; + + for (clkt = table; clkt->div; clkt++) + if (clkt->div < mindiv) + mindiv = clkt->div; + return mindiv; +} + static unsigned int _get_maxdiv(struct clk_divider *divider) { if (divider->flags & CLK_DIVIDER_ONE_BASED) @@ -162,6 +173,24 @@ static int _round_up_table(const struct clk_div_table *table, int div) return up; } +static int _round_down_table(const struct clk_div_table *table, int div) +{ + const struct clk_div_table *clkt; + int down = _get_table_mindiv(table); + + for (clkt = table; clkt->div; clkt++) { + if (clkt->div == div) + return clkt->div; + else if (clkt->div > div) + continue; + + if ((div - clkt->div) < (div - down)) + down = clkt->div; + } + + return down; +} + static int _div_round_up(struct clk_divider *divider, unsigned long parent_rate, unsigned long rate) { @@ -175,6 +204,42 @@ static int _div_round_up(struct clk_divider *divider, return div; } +static int _div_round_closest(struct clk_divider *divider, + unsigned long parent_rate, unsigned long rate) +{ + int up, down, div; + + up = down = div = DIV_ROUND_CLOSEST(parent_rate, rate); + + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) { + up = __roundup_pow_of_two(div); + down = __rounddown_pow_of_two(div); + } else if (divider->table) { + up = _round_up_table(divider->table, div); + down = _round_down_table(divider->table, div); + } + + return (up - div) <= (div - down) ? up : down; +} + +static int _div_round(struct clk_divider *divider, unsigned long parent_rate, + unsigned long rate) +{ + if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST) + return _div_round_closest(divider, parent_rate, rate); + + return _div_round_up(divider, parent_rate, rate); +} + +static bool _is_best_div(struct clk_divider *divider, + int rate, int now, int best) +{ + if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST) + return abs(rate - now) < abs(rate - best); + + return now <= rate && now > best; +} + static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, unsigned long *best_parent_rate) { @@ -190,7 +255,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) { parent_rate = *best_parent_rate; - bestdiv = _div_round_up(divider, parent_rate, rate); + bestdiv = _div_round(divider, parent_rate, rate); bestdiv = bestdiv == 0 ? 1 : bestdiv; bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv; return bestdiv; @@ -217,7 +282,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, parent_rate = __clk_round_rate(__clk_get_parent(hw->clk), MULT_ROUND_UP(rate, i)); now = parent_rate / i; - if (now <= rate && now > best) { + if (_is_best_div(divider, rate, now, best)) { bestdiv = i; best = now; *best_parent_rate = parent_rate; diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 7e59253..595f0ba 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -275,6 +275,8 @@ struct clk_div_table { * of this register, and mask of divider bits are in higher 16-bit of this * register. While setting the divider bits, higher 16-bit should also be * updated to indicate changing divider bits. + * CLK_DIVIDER_ROUND_CLOSEST - Makes the best calculated divider to be rounded + * to the closest integer instead of the up one. */ struct clk_divider { struct clk_hw hw; @@ -290,6 +292,7 @@ struct clk_divider { #define CLK_DIVIDER_POWER_OF_TWO BIT(1) #define CLK_DIVIDER_ALLOW_ZERO BIT(2) #define CLK_DIVIDER_HIWORD_MASK BIT(3) +#define CLK_DIVIDER_ROUND_CLOSEST BIT(4) extern const struct clk_ops clk_divider_ops; struct clk *clk_register_divider(struct device *dev, const char *name,
In some cases, we want to be able to round the divider to the closest one, instead than rounding up. This patch adds a new CLK_DIVIDER_ROUND_CLOSEST flag to specify the divider has to round to closest div, keeping rounding up as de default behaviour. Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com> --- drivers/clk/clk-divider.c | 69 ++++++++++++++++++++++++++++++++++++++++-- include/linux/clk-provider.h | 3 ++ 2 files changed, 70 insertions(+), 2 deletions(-)