From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
Reorganize bcm2835_clock_determine_rate so that the per
clock frequency calculation is separated from the
selection logic.
This allows for different clock selection policies
to be use while keeping code common.
Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
---
drivers/clk/bcm/clk-bcm2835.c | 98 +++++++++++++++++++++++++++++------------
1 file changed, 70 insertions(+), 28 deletions(-)
diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 48c1ad0..f1ab525 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1668,44 +1668,86 @@ unlock_exit:
return 0;
}
-static int bcm2835_clock_determine_rate(struct clk_hw *hw,
- struct clk_rate_request *req)
+struct bcm2835_rates {
+ struct clk_hw *parent;
+ unsigned long rate;
+ unsigned long prate;
+ u32 div;
+ divmash dmash;
+};
+
+static int bcm2835_clock_determine_rate_set(struct clk_rate_request *req,
+ struct bcm2835_rates *best)
{
- struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
- struct clk_hw *parent, *best_parent = NULL;
- unsigned long rate, best_rate = 0;
- unsigned long prate, best_prate = 0;
+ req->best_parent_hw = best->parent;
+ req->best_parent_rate = best->prate;
+ req->rate = best->rate;
+
+ return 0;
+}
+
+static int bcm2835_clock_determine_closest_rate(struct clk_hw *hw,
+ struct clk_rate_request *req,
+ struct bcm2835_rates *rates,
+ size_t rate_cnt)
+{
+ struct bcm2835_rates *best = NULL;
size_t i;
- divmash dm;
- u32 div;
- /*
- * Select parent clock that results in the closest but lower rate
- */
- for (i = 0; i < clk_hw_get_num_parents(hw); ++i) {
- parent = clk_hw_get_parent_by_index(hw, i);
- if (!parent)
+ /* find best matching */
+ for (i = 0; i < rate_cnt; i++) {
+ if (rates[i].rate > req->rate)
+ continue;
+ if (!best) {
+ best = &rates[i];
+ continue;
+ }
+ /* find the closest */
+ if (rates[i].rate > best->rate) {
+ best = &rates[i];
+ continue;
+ }
+ /* if identical then use highest divider */
+ if ((rates[i].rate == best->rate) &&
+ (rates[i].div > best->div)) {
+ best = &rates[i];
continue;
- prate = clk_hw_get_rate(parent);
- dm = bcm2835_clock_choose_div(hw, req->rate, prate, true);
- div = divmash_get_div(dm);
- rate = bcm2835_clock_rate_from_divisor(clock, prate, div);
- if (rate > best_rate && rate <= req->rate) {
- best_parent = parent;
- best_prate = prate;
- best_rate = rate;
}
}
- if (!best_parent)
- return -EINVAL;
+ if (best)
+ return bcm2835_clock_determine_rate_set(req, best);
+
+ /* nothing found */
+ return -EINVAL;
+}
- req->best_parent_hw = best_parent;
- req->best_parent_rate = best_prate;
+static int bcm2835_clock_determine_rate(struct clk_hw *hw,
+ struct clk_rate_request *req)
+{
+ struct bcm2835_clock *clock = bcm2835_clock_from_hw(hw);
+ struct bcm2835_rates rates[BIT(CM_SRC_BITS)];
+ size_t i, rate_cnt = 0;
+ divmash dm;
- req->rate = best_rate;
+ /* fill in rates */
+ for (i = 0; i < clk_hw_get_num_parents(hw); ++i) {
+ rates[rate_cnt].parent = clk_hw_get_parent_by_index(hw, i);
+ if (!rates[rate_cnt].parent)
+ continue;
+ rates[rate_cnt].prate = clk_hw_get_rate(
+ rates[rate_cnt].parent);
+ dm = bcm2835_clock_choose_div(
+ hw, req->rate, rates[rate_cnt].prate, true);
+ rates[rate_cnt].div = divmash_get_div(dm);
+ rates[rate_cnt].rate = bcm2835_clock_rate_from_divisor(
+ clock, rates[rate_cnt].prate, rates[rate_cnt].div);
+ rate_cnt++;
+ }
- return 0;
+ /* choose the "closest" one */
+ return bcm2835_clock_determine_closest_rate(hw, req, rates,
+ rate_cnt);
}
static int _bcm2835_clk_set_parent(struct bcm2835_cprman *cprman,
--
1.7.10.4
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
