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path: root/drivers/clk/clk-divider.c
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Diffstat (limited to 'drivers/clk/clk-divider.c')
-rw-r--r--drivers/clk/clk-divider.c25
1 files changed, 23 insertions, 2 deletions
diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
index 6d9674160430..6d55eb2cb959 100644
--- a/drivers/clk/clk-divider.c
+++ b/drivers/clk/clk-divider.c
@@ -150,6 +150,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
struct clk_divider *divider = to_clk_divider(hw);
int i, bestdiv = 0;
unsigned long parent_rate, best = 0, now, maxdiv;
+ unsigned long parent_rate_saved = *best_parent_rate;
if (!rate)
rate = 1;
@@ -173,6 +174,15 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
for (i = 1; i <= maxdiv; i++) {
if (!_is_valid_div(divider, i))
continue;
+ if (rate * i == parent_rate_saved) {
+ /*
+ * It's the most ideal case if the requested rate can be
+ * divided from parent clock without needing to change
+ * parent rate, so return the divider immediately.
+ */
+ *best_parent_rate = parent_rate_saved;
+ return i;
+ }
parent_rate = __clk_round_rate(__clk_get_parent(hw->clk),
MULT_ROUND_UP(rate, i));
now = parent_rate / i;
@@ -217,8 +227,12 @@ static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
if (divider->lock)
spin_lock_irqsave(divider->lock, flags);
- val = readl(divider->reg);
- val &= ~(div_mask(divider) << divider->shift);
+ if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
+ val = div_mask(divider) << (divider->shift + 16);
+ } else {
+ val = readl(divider->reg);
+ val &= ~(div_mask(divider) << divider->shift);
+ }
val |= value << divider->shift;
writel(val, divider->reg);
@@ -245,6 +259,13 @@ static struct clk *_register_divider(struct device *dev, const char *name,
struct clk *clk;
struct clk_init_data init;
+ if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) {
+ if (width + shift > 16) {
+ pr_warn("divider value exceeds LOWORD field\n");
+ return ERR_PTR(-EINVAL);
+ }
+ }
+
/* allocate the divider */
div = kzalloc(sizeof(struct clk_divider), GFP_KERNEL);
if (!div) {