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authorLinus Torvalds <torvalds@linux-foundation.org>2014-06-07 20:27:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-07 20:27:30 -0700
commit1a5700bc2d10cd379a795fd2bb377a190af5acd4 (patch)
treee9f754cbc34020dd23c1d2e3e45fb6890ba7593c /drivers/clk/clk-divider.c
parenta68a7509d3af8ee458d32b2416b0c2aaf2a4a7e3 (diff)
parent3cbcb16095f916f50a5a55066fcc4be06946ce1e (diff)
downloadlwn-next.tar.gz
lwn-next.zip
Merge tag 'clk-for-linus-3.16' of git://git.linaro.org/people/mike.turquette/linux into nextnext
Pull clock framework updates from Mike Turquette: "The clock framework changes for 3.16 are pretty typical: mostly clock driver additions and fixes. There are additions to the clock core code for some of the basic types (e.g. the common divider type has some fixes and featured added to it). One minor annoyance is a last-minute dependency that wasn't handled quite right. Commit ba0fae3b06a6 ("clk: berlin: add core clock driver for BG2/BG2CD") in this pull request depends on include/dt-bindings/clock/berlin2.h, which is already in your tree via the arm-soc pull request. Building for the berlin platform will break when the clk tree is built on it's own, but merged into your master branch everything should be fine" * tag 'clk-for-linus-3.16' of git://git.linaro.org/people/mike.turquette/linux: (75 commits) mmc: sunxi: Add driver for SD/MMC hosts found on Allwinner sunxi SoCs clk: export __clk_round_rate for providers clk: versatile: free icst on error return clk: qcom: Return error pointers for unimplemented clocks clk: qcom: Support msm8974pro global clock control hardware clk: qcom: Properly support display clocks on msm8974 clk: qcom: Support display RCG clocks clk: qcom: Return highest rate when round_rate() exceeds plan clk: qcom: Fix mmcc-8974's PLL configurations clk: qcom: Fix clk_rcg2_is_enabled() check clk: berlin: add core clock driver for BG2Q clk: berlin: add core clock driver for BG2/BG2CD clk: berlin: add driver for BG2x complex divider cells clk: berlin: add driver for BG2x simple PLLs clk: berlin: add driver for BG2x audio/video PLL clk: st: Terminate of match table clk/exynos4: Fix compilation warning ARM: shmobile: r8a7779: Add clock index macros for DT sources clk: divider: Fix overflow in clk_divider_bestdiv clk: u300: Terminate of match table ...
Diffstat (limited to 'drivers/clk/clk-divider.c')
-rw-r--r--drivers/clk/clk-divider.c93
1 files changed, 89 insertions, 4 deletions
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 3fbee4540228..18a9de29df0e 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 +204,54 @@ 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,
+ unsigned long rate, unsigned long now, unsigned long best)
+{
+ if (divider->flags & CLK_DIVIDER_ROUND_CLOSEST)
+ return abs(rate - now) < abs(rate - best);
+
+ return now <= rate && now > best;
+}
+
+static int _next_div(struct clk_divider *divider, int div)
+{
+ div++;
+
+ if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
+ return __roundup_pow_of_two(div);
+ if (divider->table)
+ return _round_up_table(divider->table, div);
+
+ return div;
+}
+
static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
unsigned long *best_parent_rate)
{
@@ -190,7 +267,7 @@ 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;
@@ -202,7 +279,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
*/
maxdiv = min(ULONG_MAX / rate, maxdiv);
- for (i = 1; i <= maxdiv; i++) {
+ for (i = 1; i <= maxdiv; i = _next_div(divider, i)) {
if (!_is_valid_div(divider, i))
continue;
if (rate * i == parent_rate_saved) {
@@ -217,7 +294,7 @@ 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 = DIV_ROUND_UP(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;
@@ -284,6 +361,11 @@ const struct clk_ops clk_divider_ops = {
};
EXPORT_SYMBOL_GPL(clk_divider_ops);
+const struct clk_ops clk_divider_ro_ops = {
+ .recalc_rate = clk_divider_recalc_rate,
+};
+EXPORT_SYMBOL_GPL(clk_divider_ro_ops);
+
static struct clk *_register_divider(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
void __iomem *reg, u8 shift, u8 width,
@@ -309,7 +391,10 @@ static struct clk *_register_divider(struct device *dev, const char *name,
}
init.name = name;
- init.ops = &clk_divider_ops;
+ if (clk_divider_flags & CLK_DIVIDER_READ_ONLY)
+ init.ops = &clk_divider_ro_ops;
+ else
+ init.ops = &clk_divider_ops;
init.flags = flags | CLK_IS_BASIC;
init.parent_names = (parent_name ? &parent_name: NULL);
init.num_parents = (parent_name ? 1 : 0);