From: Frank Oltmanns <frank@oltmanns.dev>
To: "Michael Turquette" <mturquette@baylibre.com>,
"Stephen Boyd" <sboyd@kernel.org>, "Chen-Yu Tsai" <wens@csie.org>,
"Jernej Skrabec" <jernej.skrabec@gmail.com>,
"Samuel Holland" <samuel@sholland.org>,
"Guido Günther" <agx@sigxcpu.org>,
"Purism Kernel Team" <kernel@puri.sm>,
"Ondrej Jirman" <megi@xff.cz>,
"Neil Armstrong" <neil.armstrong@linaro.org>,
"Jessica Zhang" <quic_jesszhan@quicinc.com>,
"Sam Ravnborg" <sam@ravnborg.org>,
"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
"Maxime Ripard" <mripard@kernel.org>,
"Thomas Zimmermann" <tzimmermann@suse.de>,
"David Airlie" <airlied@gmail.com>,
"Daniel Vetter" <daniel@ffwll.ch>
Cc: linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org,
Frank Oltmanns <frank@oltmanns.dev>
Subject: [PATCH 1/5] clk: sunxi-ng: nkm: Support constraints on m/n ratio and parent rate
Date: Mon, 18 Dec 2023 14:35:19 +0100 [thread overview]
Message-ID: <20231218-pinephone-pll-fixes-v1-1-e238b6ed6dc1@oltmanns.dev> (raw)
In-Reply-To: <20231218-pinephone-pll-fixes-v1-0-e238b6ed6dc1@oltmanns.dev>
The Allwinner A64 manual lists the following constraints for the
PLL-MIPI clock:
- M/N >= 3
- (PLL_VIDEO0)/M >= 24MHz
The PLL-MIPI clock is implemented as ccu_nkm. Therefore, add support for
these constraints.
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
drivers/clk/sunxi-ng/ccu_nkm.c | 23 +++++++++++++++++++++++
drivers/clk/sunxi-ng/ccu_nkm.h | 8 ++++++++
2 files changed, 31 insertions(+)
diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
index eed64547ad42..2af5c1ebd527 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -16,6 +16,20 @@ struct _ccu_nkm {
unsigned long m, min_m, max_m;
};
+static bool ccu_nkm_is_valid_rate(struct ccu_common *common, unsigned long parent,
+ unsigned long n, unsigned long m)
+{
+ struct ccu_nkm *nkm = container_of(common, struct ccu_nkm, common);
+
+ if (nkm->max_mn_ratio && (m > nkm->max_mn_ratio * n))
+ return false;
+
+ if (nkm->parent_wo_nk && (parent < nkm->parent_wo_nk * m))
+ return false;
+
+ return true;
+}
+
static unsigned long ccu_nkm_find_best_with_parent_adj(struct ccu_common *common,
struct clk_hw *parent_hw,
unsigned long *parent, unsigned long rate,
@@ -32,6 +46,9 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(struct ccu_common *common
tmp_parent = clk_hw_round_rate(parent_hw, rate * _m / (_n * _k));
+ if (!ccu_nkm_is_valid_rate(common, tmp_parent, _n, _m))
+ continue;
+
tmp_rate = tmp_parent * _n * _k / _m;
if (ccu_is_better_rate(common, rate, tmp_rate, best_rate) ||
@@ -65,6 +82,12 @@ static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
for (_k = nkm->min_k; _k <= nkm->max_k; _k++) {
for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
+ if ((common->reg == 0x040) && (_m > 3 * _n))
+ break;
+
+ if ((common->reg == 0x040) && (parent < 24000000 * _m))
+ continue;
+
unsigned long tmp_rate;
tmp_rate = parent * _n * _k / _m;
diff --git a/drivers/clk/sunxi-ng/ccu_nkm.h b/drivers/clk/sunxi-ng/ccu_nkm.h
index 6601defb3f38..d3d3eaf55faf 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.h
+++ b/drivers/clk/sunxi-ng/ccu_nkm.h
@@ -16,6 +16,12 @@
* struct ccu_nkm - Definition of an N-K-M clock
*
* Clocks based on the formula parent * N * K / M
+ *
+ * @max_mn_ratio: Maximum value for M / N.
+ * @parent_wo_nk: The minimum rate the parent must provide after applying the divisor,
+ * but without applying the multipliers, i.e. the contstraint
+ * (parent rate)/M >= parent_wo_nk
+ * must be fulfilled.
*/
struct ccu_nkm {
u32 enable;
@@ -27,6 +33,8 @@ struct ccu_nkm {
struct ccu_mux_internal mux;
unsigned int fixed_post_div;
+ unsigned long max_mn_ratio;
+ unsigned long parent_wo_nk;
struct ccu_common common;
};
--
2.43.0
next prev parent reply other threads:[~2023-12-18 13:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-18 13:35 [PATCH 0/5] Pinephone video out fixes (flipping between two frames) Frank Oltmanns
2023-12-18 13:35 ` Frank Oltmanns [this message]
2023-12-18 17:26 ` [PATCH 1/5] clk: sunxi-ng: nkm: Support constraints on m/n ratio and parent rate Frank Oltmanns
2023-12-19 16:46 ` Jernej Škrabec
2023-12-20 6:58 ` Frank Oltmanns
2023-12-20 15:09 ` Jernej Škrabec
2023-12-18 13:35 ` [PATCH 2/5] clk: sunxi-ng: a64: Add constraints on PLL-MIPI's n/m " Frank Oltmanns
2023-12-19 16:46 ` Jernej Škrabec
2023-12-18 13:35 ` [PATCH 3/5] clk: sunxi-ng: nm: Support constraints on " Frank Oltmanns
2023-12-19 16:52 ` Jernej Škrabec
2023-12-18 13:35 ` [PATCH 4/5] clk: sunxi-ng: a64: Add constraints on PLL-VIDEO0's n/m ratio Frank Oltmanns
2023-12-19 16:54 ` Jernej Škrabec
2023-12-20 7:09 ` Frank Oltmanns
2023-12-20 15:12 ` Jernej Škrabec
2023-12-22 7:46 ` Frank Oltmanns
2023-12-31 9:10 ` Frank Oltmanns
2024-01-09 20:29 ` Jernej Škrabec
2023-12-18 13:35 ` [PATCH 5/5] drm/panel: st7703: Drive XBD599 panel at higher clock rate Frank Oltmanns
2023-12-19 17:04 ` Jernej Škrabec
2023-12-20 7:14 ` Frank Oltmanns
2023-12-20 15:18 ` Jernej Škrabec
2023-12-20 18:57 ` Frank Oltmanns
2023-12-22 9:10 ` Frank Oltmanns
2023-12-22 17:36 ` Jernej Škrabec
2023-12-30 21:17 ` Frank Oltmanns
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