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Message-Id: <20230702-pll-mipi_set_rate_parent-v3-5-46dcb8aa9cbc@oltmanns.dev>
Date: Sun, 02 Jul 2023 19:55:24 +0200
From: Frank Oltmanns <frank@...manns.dev>
To: Maxime Ripard <maxime@...no.tech>,
Michael Turquette <mturquette@...libre.com>,
Stephen Boyd <sboyd@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
Jernej Skrabec <jernej.skrabec@...il.com>,
Samuel Holland <samuel@...lland.org>,
Andre Przywara <andre.przywara@....com>,
Roman Beranek <me@...y.cz>
Cc: linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org,
Frank Oltmanns <frank@...manns.dev>
Subject: [PATCH v3 5/8] clk: sunxi-ng: nkm: Support finding closest rate
When finding the best rate for a NKM clock, consider rates that are
higher than the requested rate, if the CCU_FEATURE_CLOSEST_RATE flag is
set.
Accommodate ccu_mux_helper_determine_rate to this change.
Signed-off-by: Frank Oltmanns <frank@...manns.dev>
---
drivers/clk/sunxi-ng/ccu_mux.c | 23 +++++++++++++++-----
drivers/clk/sunxi-ng/ccu_nkm.c | 48 +++++++++++++++++++++++++++++++-----------
2 files changed, 54 insertions(+), 17 deletions(-)
diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
index 1d557e323169..8594d6a4addd 100644
--- a/drivers/clk/sunxi-ng/ccu_mux.c
+++ b/drivers/clk/sunxi-ng/ccu_mux.c
@@ -113,7 +113,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
}
for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
- unsigned long tmp_rate, parent_rate;
+ unsigned long tmp_rate, parent_rate, best_diff = ULONG_MAX;
struct clk_hw *parent;
parent = clk_hw_get_parent_by_index(hw, i);
@@ -139,10 +139,23 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
goto out;
}
- if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
- best_rate = tmp_rate;
- best_parent_rate = parent_rate;
- best_parent = parent;
+ if (common->features & CCU_FEATURE_CLOSEST_RATE) {
+ unsigned long tmp_diff = req->rate > tmp_rate ?
+ req->rate - tmp_rate :
+ tmp_rate - req->rate;
+
+ if (tmp_diff < best_diff) {
+ best_rate = tmp_rate;
+ best_parent_rate = parent_rate;
+ best_parent = parent;
+ best_diff = tmp_diff;
+ }
+ } else {
+ if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
+ best_rate = tmp_rate;
+ best_parent_rate = parent_rate;
+ best_parent = parent;
+ }
}
}
diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
index d83843e69c25..36d9e987e4d8 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -18,9 +18,11 @@ struct _ccu_nkm {
};
static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, unsigned long rate,
- struct _ccu_nkm *nkm, struct clk_hw *phw)
+ struct _ccu_nkm *nkm, struct clk_hw *phw,
+ unsigned long features)
{
- unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent;
+ unsigned long best_rate = 0, best_parent_rate = 0, tmp_parent = *parent;
+ unsigned long best_diff = ULONG_MAX;
unsigned long best_n = 0, best_k = 0, best_m = 0;
unsigned long _n, _k, _m;
@@ -28,16 +30,26 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, un
for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
unsigned long tmp_rate;
+ unsigned long tmp_diff;
tmp_parent = clk_hw_round_rate(phw, rate * _m / (_n * _k));
tmp_rate = tmp_parent * _n * _k / _m;
- if (tmp_rate > rate)
- continue;
- if ((rate - tmp_rate) < (rate - best_rate)) {
+ if (features & CCU_FEATURE_CLOSEST_RATE) {
+ tmp_diff = rate > tmp_rate ?
+ rate - tmp_rate :
+ tmp_rate - rate;
+ } else {
+ if (tmp_rate > rate)
+ continue;
+ tmp_diff = rate - tmp_diff;
+ }
+
+ if (tmp_diff < best_diff) {
best_rate = tmp_rate;
best_parent_rate = tmp_parent;
+ best_diff = tmp_diff;
best_n = _n;
best_k = _k;
best_m = _m;
@@ -56,9 +68,10 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(unsigned long *parent, un
}
static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
- struct _ccu_nkm *nkm)
+ struct _ccu_nkm *nkm, unsigned long features)
{
unsigned long best_rate = 0;
+ unsigned long best_diff = ULONG_MAX;
unsigned long best_n = 0, best_k = 0, best_m = 0;
unsigned long _n, _k, _m;
@@ -66,13 +79,23 @@ static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
unsigned long tmp_rate;
+ unsigned long tmp_diff;
tmp_rate = parent * _n * _k / _m;
- if (tmp_rate > rate)
- continue;
- if ((rate - tmp_rate) < (rate - best_rate)) {
+ if (features & CCU_FEATURE_CLOSEST_RATE) {
+ tmp_diff = rate > tmp_rate ?
+ rate - tmp_rate :
+ tmp_rate - rate;
+ } else {
+ if (tmp_rate > rate)
+ continue;
+ tmp_diff = rate - tmp_diff;
+ }
+
+ if (tmp_diff < best_diff) {
best_rate = tmp_rate;
+ best_diff = tmp_diff;
best_n = _n;
best_k = _k;
best_m = _m;
@@ -164,9 +187,10 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
rate *= nkm->fixed_post_div;
if (!clk_hw_can_set_rate_parent(&nkm->common.hw))
- rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm);
+ rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm, nkm->common.features);
else
- rate = ccu_nkm_find_best_with_parent_adj(parent_rate, rate, &_nkm, parent_hw);
+ rate = ccu_nkm_find_best_with_parent_adj(parent_rate, rate, &_nkm, parent_hw,
+ nkm->common.features);
if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
rate /= nkm->fixed_post_div;
@@ -201,7 +225,7 @@ static int ccu_nkm_set_rate(struct clk_hw *hw, unsigned long rate,
_nkm.min_m = 1;
_nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;
- ccu_nkm_find_best(&parent_rate, rate, &_nkm);
+ ccu_nkm_find_best(parent_rate, rate, &_nkm, nkm->common.features);
spin_lock_irqsave(nkm->common.lock, flags);
--
2.41.0
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