[PATCH v4 00/11] clk: sunxi-ng: Consider alternative parent rates when determining NKM clock rate

[PATCH v4 00/11] clk: sunxi-ng: Consider alternative parent rates when determining NKM clock rate

[Frank Oltmanns]

This patchset enables NKM clocks to consider alternative parent rates
and utilize this new feature to adjust the pll-video0 clock on Allwinner
A64 (PATCH 2 and 3).

Furthermore, with this patchset pll-video0 considers rates that are
higher than the requested rate when finding the closest rate. In
consequence, higher rates are also considered by pll-video0's
descandents (PATCH 4 et. seq.). In total, after applying this patchset,
finding the closest rate is supported by:
  - ccu_nm
  - ccu_nkm
  - ccu_mux
  - ccu_div

This allows us to achieve an optimal rate for driving the board's panel.

To provide some context, the clock structure involved in this process is
as follows:
    clock                       clock type
    --------------------------------------
    pll-video0                  ccu_nm
       pll-mipi                 ccu_nkm
          tcon0                 ccu_mux
             tcon-data-clock    sun4i_dclk

The divider between tcon0 and tcon-data-clock is fixed at 4. Therefore,
in order to achieve a rate that closely matches the desired rate of the
panel, pll-mipi needs to operate at a specific rate.

Tests
=====
So far, this has been successfully tested on the A64-based Pinephone
using three different panel rates:

 1. A panel rate that can be matched exactly by pll-video0.
 2. A panel rate that requires pll-video0 to undershoot to get the
    closest rate.
 3. A panel rate that requires pll-video0 to overshoot to get the
    closest rate.

Test records:

Re 1:
-----
Panel requests tcon-data-clock of 103500000 Hz, i.e., pll-mipi needs to
run at 414000000 Hz. This results in the following clock rates:
   clock                            rate
   -------------------------------------
    pll-video0                 207000000
       hdmi-phy-clk             51750000
       hdmi                    207000000
       tcon1                   207000000
       pll-mipi                414000000
          tcon0                414000000
             tcon-data-clock   103500000

The results of the find_best calls:
ccu_nkm_find_best_with_parent_adj: rate=414000000, best_rate=414000000, best_parent_rate=207000000, n=1, k=2, m=1
ccu_nkm_find_best_with_parent_adj: rate=414000000, best_rate=414000000, best_parent_rate=207000000, n=1, k=2, m=1
ccu_nkm_find_best_with_parent_adj: rate=414000000, best_rate=414000000, best_parent_rate=207000000, n=1, k=2, m=1
ccu_nkm_find_best_with_parent_adj: rate=414000000, best_rate=414000000, best_parent_rate=207000000, n=1, k=2, m=1
ccu_nkm_find_best: rate=414000000, best_rate=414000000, parent_rate=207000000, n=1, k=2, m=1

Re 2:
-----
Panel requests tcon-data-clock of 103650000 Hz, i.e., pll-mipi needs to
run at 414600000 Hz. This results in the following clock rates:
   clock                            rate
   -------------------------------------
    pll-video0                 282666666
       hdmi-phy-clk             70666666
       hdmi                    282666666
       tcon1                   282666666
       pll-mipi                414577776
          tcon0                414577776
             tcon-data-clock   103644444

The results of the find_best calls:
ccu_nkm_find_best_with_parent_adj: rate=414600000, best_rate=414577776, best_parent_rate=282666666, n=11, k=2, m=15
ccu_nkm_find_best_with_parent_adj: rate=414600000, best_rate=414577776, best_parent_rate=282666666, n=11, k=2, m=15
ccu_nkm_find_best_with_parent_adj: rate=414577776, best_rate=414577776, best_parent_rate=282666666, n=11, k=2, m=15
ccu_nkm_find_best_with_parent_adj: rate=414577776, best_rate=414577776, best_parent_rate=282666666, n=11, k=2, m=15
ccu_nkm_find_best: rate=414577776, best_rate=414577776, parent_rate=282666666, n=11, k=2, m=15

Here, we first ask pll-video0 for a rate that it can't provide exactly:
 - rate=414600000: We ask the parent for rate * m / (n * k) = 282681818,
   it returns 282666666. Here the parent undershoots.
Later we ask pll-video0 for exactly that rate again:
 - rate=414577776: We ask the parent for DIV_ROUND_UP(rate * m, n * k) =
   282666666, which it then returns.

Re 3:
-----
Panel requests tcon-data-clock of 112266000 Hz, i.e., pll-mipi needs to
run at 449064000 Hz. This results in the following clock rates:
   clock                            rate
   -------------------------------------
    pll-video0                 207272727
       hdmi-phy-clk             51818181
       hdmi                    207272727
       tcon1                   207272727
       pll-mipi                449090908
          tcon0                449090908
             tcon-data-clock   112272727

The results of the find_best calls:
ccu_nkm_find_best_with_parent_adj: rate=449064000, best_rate=449090908, best_parent_rate=207272727, n=13, k=2, m=12
ccu_nkm_find_best_with_parent_adj: rate=449064000, best_rate=449090908, best_parent_rate=207272727, n=13, k=2, m=12
ccu_nkm_find_best_with_parent_adj: rate=449090908, best_rate=449090908, best_parent_rate=207272727, n=13, k=2, m=12
ccu_nkm_find_best_with_parent_adj: rate=449090908, best_rate=449090908, best_parent_rate=207272727, n=13, k=2, m=12
ccu_nkm_find_best: rate=449090908, best_rate=449090908, parent_rate=207272727, n=13, k=2, m=12

Here, we first ask the pll-video0 for a rate that it can't provide
exactly:
 - rate=449064000: We ask the parent for DIV_ROUND_UP(rate * m, n * k) =
   207260308, it returns 207272727. Here the parent overshoots.
Later we ask pll-video0 for exactly that rate again:
 - rate=449090908: We ask the parent for DIV_ROUND_UP(rate * m, n * k) =
   207272727, which it then returns.

Changelog:
----------
Changes in v4:
 - Re-introduce a dedicated function for calculating the optimal parent
   rate for nkm clocks that was introduced in v2 and removed in v3. It
   turned out that not having this functionality introduces a bug when
   the parent does not support finding the closest rate:
   https://lore.kernel.org/all/87pm4xg2ub.fsf@oltmanns.dev/
 - Incorporate review remarks:
    - Correcting the parameter name for ccu_nkm_round_rate()'s parent HW
      is now in a separate patch.
    - Use correct parameter order in ccu_nkm_find_best_with_parent_adj.
    - Add ccu_is_better_rate() and use it for determining the best rate
      for nm and nkm, as well as ccu_mux_helper_determine_rate.
    - Consistently introduce new macros for clock variants that support
      finding the closest rate instead of updating existing macros.
    - Use wrapper function for determining a ccu_mux's rate in order to
      support finding the closest rate.
 - Link to v3: https://lore.kernel.org/r/20230702-pll-mipi_set_rate_parent-v3-0-46dcb8aa9cbc@oltmanns.dev

Changes in v3:
 - Use dedicated function for finding the best rate in cases where an
   nkm clock supports setting its parent's rate, streamlining it with
   the structure that is used in other sunxi-ng ccus such as ccu_mp
   (PATCH 1).
 - Therefore, remove the now obsolete comments that were introduced in
   v2 (PATCH 1).
 - Remove the dedicated function for calculating the optimal parent rate
   for nkm clocks that was introduced in v2. Instead use a simple
   calculation and require the parent clock to select the closest rate to
   achieve optimal results (PATCH 1).
 - Therefore, add support to set the closest rate for nm clocks (because
   pll-mipi's parent pll-video0 is an nm clock) and all clock types that
   are descendants of a64's pll-video0, i.e., nkm, mux, and div (PATCH 3
   et. seq.).
 - Link to v2: https://lore.kernel.org/all/20230611090143.132257-1-frank@oltmanns.dev/

Changes in V2:
 - Move optimal parent rate calculation to dedicated function
 - Choose a parent rate that does not to overshoot requested rate
 - Add comments to ccu_nkm_find_best
 - Make sure that best_parent_rate stays at original parent rate in the unlikely
   case that all combinations overshoot.

Link to V1:
https://lore.kernel.org/lkml/20230605190745.366882-1-frank@oltmanns.dev/

---
Frank Oltmanns (11):
      clk: sunxi-ng: nkm: Use correct parameter name for parent HW
      clk: sunxi-ng: nkm: consider alternative parent rates when determining rate
      clk: sunxi-ng: nkm: Improve determine rate when setting parent
      clk: sunxi-ng: a64: allow pll-mipi to set parent's rate
      clk: sunxi-ng: Add feature to find closest rate
      clk: sunxi-ng: Add helper function to find closest rate
      clk: sunxi-ng: nm: Support finding closest rate
      clk: sunxi-ng: nkm: Support finding closest rate
      clk: sunxi-ng: mux: Support finding closest rate
      clk: sunxi-ng: div: Support finding closest rate
      clk: sunxi-ng: a64: select closest rate for pll-video0

 drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 36 ++++++++---------
 drivers/clk/sunxi-ng/ccu_common.c     | 12 ++++++
 drivers/clk/sunxi-ng/ccu_common.h     |  6 +++
 drivers/clk/sunxi-ng/ccu_div.h        | 30 ++++++++++++++
 drivers/clk/sunxi-ng/ccu_mux.c        | 15 ++++++-
 drivers/clk/sunxi-ng/ccu_mux.h        | 38 +++++++++++++-----
 drivers/clk/sunxi-ng/ccu_nkm.c        | 76 +++++++++++++++++++++++++++++++----
 drivers/clk/sunxi-ng/ccu_nm.c         | 11 ++---
 drivers/clk/sunxi-ng/ccu_nm.h         | 48 ++++++++++++++++++++--
 9 files changed, 222 insertions(+), 50 deletions(-)
---
base-commit: 6995e2de6891c724bfeb2db33d7b87775f913ad1
change-id: 20230626-pll-mipi_set_rate_parent-3363fc0d6e6f

Best regards,
-- 
Frank Oltmanns <frank@oltmanns.dev>


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 01/11] clk: sunxi-ng: nkm: Use correct parameter name for parent HW

[Frank Oltmanns]

ccu_nkm_round_rate() takes a clk_hw as parameter "hw". Since "hw" is the
nkm clock's parent clk_hw, not the clk_hw of the nkm clock itself,
change the parameter name to "parent_hw" to make it more clear what
we're dealing with.

Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_nkm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
index a0978a50edae..f267142e58b3 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -106,7 +106,7 @@ static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
 }
 
 static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
-					struct clk_hw *hw,
+					struct clk_hw *parent_hw,
 					unsigned long *parent_rate,
 					unsigned long rate,
 					void *data)

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4 01/11] clk: sunxi-ng: nkm: Use correct parameter name for parent HW

[Maxime Ripard]

On Mon, 17 Jul 2023 15:34:25 +0200, Frank Oltmanns wrote:
> ccu_nkm_round_rate() takes a clk_hw as parameter "hw". Since "hw" is the
> nkm clock's parent clk_hw, not the clk_hw of the nkm clock itself,
> change the parameter name to "parent_hw" to make it more clear what
> we're dealing with.
> 
> 
> [ ... ]

Acked-by: Maxime Ripard <mripard@kernel.org>

Thanks!
Maxime

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 02/11] clk: sunxi-ng: nkm: consider alternative parent rates when determining rate

[Frank Oltmanns]

In case the CLK_SET_RATE_PARENT flag is set, consider using a different
parent rate when determining a new rate.

To find the best match for the requested rate, perform the following
steps for each NKM combination:
 - calculate the optimal parent rate,
 - find the best parent rate that the parent clock actually supports
 - use that parent rate to calculate the effective rate.

In case the clk does not support setting the parent rate, use the same
algorithm as before.

Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_nkm.c | 44 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
index f267142e58b3..750e2b8da24b 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -6,6 +6,7 @@
 
 #include <linux/clk-provider.h>
 #include <linux/io.h>
+#include <linux/math.h>
 
 #include "ccu_gate.h"
 #include "ccu_nkm.h"
@@ -16,6 +17,44 @@ struct _ccu_nkm {
 	unsigned long	m, min_m, max_m;
 };
 
+static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struct _ccu_nkm *nkm,
+						       unsigned long *parent, unsigned long rate)
+{
+	unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent;
+	unsigned long best_n = 0, best_k = 0, best_m = 0;
+	unsigned long _n, _k, _m;
+
+	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++) {
+				unsigned long tmp_rate;
+
+				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)) {
+					best_rate = tmp_rate;
+					best_parent_rate = tmp_parent;
+					best_n = _n;
+					best_k = _k;
+					best_m = _m;
+				}
+			}
+		}
+	}
+
+	nkm->n = best_n;
+	nkm->k = best_k;
+	nkm->m = best_m;
+
+	*parent = best_parent_rate;
+
+	return best_rate;
+}
+
 static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
 				       struct _ccu_nkm *nkm)
 {
@@ -124,7 +163,10 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
 	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 		rate *= nkm->fixed_post_div;
 
-	rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm);
+	if (!clk_hw_can_set_rate_parent(&nkm->common.hw))
+		rate = ccu_nkm_find_best(*parent_rate, rate, &_nkm);
+	else
+		rate = ccu_nkm_find_best_with_parent_adj(parent_hw, &_nkm, parent_rate, rate);
 
 	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 		rate /= nkm->fixed_post_div;

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4 02/11] clk: sunxi-ng: nkm: consider alternative parent rates when determining rate

[Maxime Ripard]

On Mon, 17 Jul 2023 15:34:26 +0200, Frank Oltmanns wrote:
> In case the CLK_SET_RATE_PARENT flag is set, consider using a different
> parent rate when determining a new rate.
> 
> To find the best match for the requested rate, perform the following
> steps for each NKM combination:
> 
> [ ... ]

Acked-by: Maxime Ripard <mripard@kernel.org>

Thanks!
Maxime

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 03/11] clk: sunxi-ng: nkm: Improve determine rate when setting parent

[Frank Oltmanns]

Make the SET_PARENT_RATE flag independent of the parents round_rate or
determine_rate implementation.

Currently, the algorithm for ccu_nkm_find_best_with_parent_adj simply
calculates the optimal parent rate as
    (1) parent = rate * m / (n * k)

Due to integer division (1) might return a parent rate that is too low.
So using this value for asking the parent for a rate it supports via
clk_hw_round_rate causes problems on
 a) parents that only support finding rates that are lower than the
    requested rate - which is the default for sunxi-ng ccu's.
 b) parents that incidentally also support the truncated rate.

In those cases ccu_nkm_determine_rate might return A' when A is
requested and A'' when rate A' is requested.

Prevent this by trying to find a parent rate so that
    (2) _rate = parent * n * k / m
matches the requested rate exactly, if possible.

Background:
===========
determine_rate may be called multiple times by the clk framework when
setting a clock's rate. But the clk framework expects that the values
determine_rate returns (i.e. the rate and parent_rate) are consistent
with previous calls.

Specifically, clock's have to ensure that if determine_rate is called
with requested rate A and the best rate it can find is A', it must also
return A' when called with requested rate A'.

Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_nkm.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
index 750e2b8da24b..793160bc2d47 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -17,6 +17,27 @@ struct _ccu_nkm {
 	unsigned long	m, min_m, max_m;
 };
 
+/*
+ * Calculate the optimal parent when determining the nkm clock's rate.
+ *
+ * This function is used when the nkm clock supports setting the parent rate and ensures that the
+ * determine_rate function returns consistent values. I.e., when determine rate is called for rate A
+ * and the best rate it can find is A', this function ensures that determine_rate will also return
+ * A' when A' is requested.
+ */
+static unsigned long ccu_nkm_optimal_parent_rate(unsigned long rate, unsigned long n,
+				 unsigned long k, unsigned long m)
+{
+	unsigned long _rate, parent;
+
+	parent = DIV_ROUND_UP(rate * m, n * k);
+
+	_rate = parent * n * k / m;
+	if (_rate > rate)
+		parent = rate * m / (n * k);
+	return parent;
+}
+
 static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struct _ccu_nkm *nkm,
 						       unsigned long *parent, unsigned long rate)
 {
@@ -29,7 +50,8 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struc
 			for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
 				unsigned long tmp_rate;
 
-				tmp_parent = clk_hw_round_rate(phw, rate * _m / (_n * _k));
+				tmp_parent = ccu_nkm_optimal_parent_rate(rate, _n, _k, _m);
+				tmp_parent = clk_hw_round_rate(phw, tmp_parent);
 
 				tmp_rate = tmp_parent * _n * _k / _m;
 				if (tmp_rate > rate)

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4 03/11] clk: sunxi-ng: nkm: Improve determine rate when setting parent

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 1612 bytes --]

Hi,

On Mon, Jul 17, 2023 at 03:34:27PM +0200, Frank Oltmanns wrote:
> Make the SET_PARENT_RATE flag independent of the parents round_rate or
> determine_rate implementation.
> 
> Currently, the algorithm for ccu_nkm_find_best_with_parent_adj simply
> calculates the optimal parent rate as
>     (1) parent = rate * m / (n * k)
> 
> Due to integer division (1) might return a parent rate that is too low.
> So using this value for asking the parent for a rate it supports via
> clk_hw_round_rate causes problems on
>  a) parents that only support finding rates that are lower than the
>     requested rate - which is the default for sunxi-ng ccu's.
>  b) parents that incidentally also support the truncated rate.
> 
> In those cases ccu_nkm_determine_rate might return A' when A is
> requested and A'' when rate A' is requested.
> 
> Prevent this by trying to find a parent rate so that
>     (2) _rate = parent * n * k / m
> matches the requested rate exactly, if possible.
> 
> Background:
> ===========
> determine_rate may be called multiple times by the clk framework when
> setting a clock's rate. But the clk framework expects that the values
> determine_rate returns (i.e. the rate and parent_rate) are consistent
> with previous calls.
> 
> Specifically, clock's have to ensure that if determine_rate is called
> with requested rate A and the best rate it can find is A', it must also
> return A' when called with requested rate A'.
> 
> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>

As stated in my earlier mail, I still disagree with that patch.

Maxime

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 04/11] clk: sunxi-ng: a64: allow pll-mipi to set parent's rate

[Frank Oltmanns]

The nkm clock now supports setting the parent's rate. Utilize this
option to find the optimal rate for pll-mipi.

Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
index 41519185600a..a139a5c438d4 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
@@ -179,7 +179,8 @@ static struct ccu_nkm pll_mipi_clk = {
 	.common		= {
 		.reg		= 0x040,
 		.hw.init	= CLK_HW_INIT("pll-mipi", "pll-video0",
-					      &ccu_nkm_ops, CLK_SET_RATE_UNGATE),
+					      &ccu_nkm_ops,
+					      CLK_SET_RATE_UNGATE | CLK_SET_RATE_PARENT),
 	},
 };
 

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 05/11] clk: sunxi-ng: Add feature to find closest rate

[Frank Oltmanns]

The default behaviour of clocks in the sunxi-ng driver is to select a
clock rate that is closest to but less than the requested rate.

Add the CCU_FEATURE_CLOSEST_RATE flag, which can be used to allow clocks
to find the closest rate instead.

Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_common.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/clk/sunxi-ng/ccu_common.h b/drivers/clk/sunxi-ng/ccu_common.h
index fbf16c6b896d..5ad219f041d5 100644
--- a/drivers/clk/sunxi-ng/ccu_common.h
+++ b/drivers/clk/sunxi-ng/ccu_common.h
@@ -18,6 +18,7 @@
 #define CCU_FEATURE_MMC_TIMING_SWITCH	BIT(6)
 #define CCU_FEATURE_SIGMA_DELTA_MOD	BIT(7)
 #define CCU_FEATURE_KEY_FIELD		BIT(8)
+#define CCU_FEATURE_CLOSEST_RATE	BIT(9)
 
 /* MMC timing mode switch bit */
 #define CCU_MMC_NEW_TIMING_MODE		BIT(30)

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 06/11] clk: sunxi-ng: Add helper function to find closest rate

[Frank Oltmanns]

The default behaviour of clocks in the sunxi-ng driver is to select a
clock rate that is closest to but less than the requested rate.

Add the ccu_is_better_rate() helper function that - depending on the
fact if thc CCU_FEATURE_CLOSEST_RATE flag is set - decides if a rate is
closer than another rate.

Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_common.c | 12 ++++++++++++
 drivers/clk/sunxi-ng/ccu_common.h |  5 +++++
 2 files changed, 17 insertions(+)

diff --git a/drivers/clk/sunxi-ng/ccu_common.c b/drivers/clk/sunxi-ng/ccu_common.c
index 8d28a7a079d0..8babce55302f 100644
--- a/drivers/clk/sunxi-ng/ccu_common.c
+++ b/drivers/clk/sunxi-ng/ccu_common.c
@@ -39,6 +39,18 @@ void ccu_helper_wait_for_lock(struct ccu_common *common, u32 lock)
 }
 EXPORT_SYMBOL_NS_GPL(ccu_helper_wait_for_lock, SUNXI_CCU);
 
+bool ccu_is_better_rate(struct ccu_common *common,
+			unsigned long target_rate,
+			unsigned long current_rate,
+			unsigned long best_rate)
+{
+	if (common->features & CCU_FEATURE_CLOSEST_RATE)
+		return abs(current_rate - target_rate) < abs(best_rate - target_rate);
+
+	return current_rate <= target_rate && current_rate > best_rate;
+}
+EXPORT_SYMBOL_NS_GPL(ccu_is_better_rate, SUNXI_CCU);
+
 /*
  * This clock notifier is called when the frequency of a PLL clock is
  * changed. In common PLL designs, changes to the dividers take effect
diff --git a/drivers/clk/sunxi-ng/ccu_common.h b/drivers/clk/sunxi-ng/ccu_common.h
index 5ad219f041d5..942a72c09437 100644
--- a/drivers/clk/sunxi-ng/ccu_common.h
+++ b/drivers/clk/sunxi-ng/ccu_common.h
@@ -53,6 +53,11 @@ struct sunxi_ccu_desc {
 
 void ccu_helper_wait_for_lock(struct ccu_common *common, u32 lock);
 
+bool ccu_is_better_rate(struct ccu_common *common,
+			unsigned long target_rate,
+			unsigned long current_rate,
+			unsigned long best_rate);
+
 struct ccu_pll_nb {
 	struct notifier_block	clk_nb;
 	struct ccu_common	*common;

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4 06/11] clk: sunxi-ng: Add helper function to find closest rate

[Maxime Ripard]

On Mon, 17 Jul 2023 15:34:30 +0200, Frank Oltmanns wrote:
> The default behaviour of clocks in the sunxi-ng driver is to select a
> clock rate that is closest to but less than the requested rate.
> 
> Add the ccu_is_better_rate() helper function that - depending on the
> fact if thc CCU_FEATURE_CLOSEST_RATE flag is set - decides if a rate is
> 
> [ ... ]

Acked-by: Maxime Ripard <mripard@kernel.org>

Thanks!
Maxime

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 07/11] clk: sunxi-ng: nm: Support finding closest rate

[Frank Oltmanns]

Use the helper function ccu_is_better_rate() to determine the rate that
is closest to the requested rate, thereby supporting rates that are
higher than the requested rate if the clock uses the
CCU_FEATURE_CLOSEST_RATE.

Add the macro SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST which
sets CCU_FEATURE_CLOSEST_RATE.

To avoid code duplication, add the macros
SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT that allows selecting
arbitrary features and use it in the original
SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX as well as the newly introduced
SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST macros.

Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_nm.c | 11 ++++------
 drivers/clk/sunxi-ng/ccu_nm.h | 48 ++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 49 insertions(+), 10 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_nm.c
index c1fd11542c45..35d00783d748 100644
--- a/drivers/clk/sunxi-ng/ccu_nm.c
+++ b/drivers/clk/sunxi-ng/ccu_nm.c
@@ -28,7 +28,7 @@ static unsigned long ccu_nm_calc_rate(unsigned long parent,
 }
 
 static unsigned long ccu_nm_find_best(unsigned long parent, unsigned long rate,
-				      struct _ccu_nm *nm)
+				      struct _ccu_nm *nm, struct ccu_common *common)
 {
 	unsigned long best_rate = 0;
 	unsigned long best_n = 0, best_m = 0;
@@ -39,10 +39,7 @@ static unsigned long ccu_nm_find_best(unsigned long parent, unsigned long rate,
 			unsigned long tmp_rate = ccu_nm_calc_rate(parent,
 								  _n, _m);
 
-			if (tmp_rate > rate)
-				continue;
-
-			if ((rate - tmp_rate) < (rate - best_rate)) {
+			if (ccu_is_better_rate(common, rate, tmp_rate, best_rate)) {
 				best_rate = tmp_rate;
 				best_n = _n;
 				best_m = _m;
@@ -159,7 +156,7 @@ static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
 	_nm.min_m = 1;
 	_nm.max_m = nm->m.max ?: 1 << nm->m.width;
 
-	rate = ccu_nm_find_best(*parent_rate, rate, &_nm);
+	rate = ccu_nm_find_best(*parent_rate, rate, &_nm, &nm->common);
 
 	if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 		rate /= nm->fixed_post_div;
@@ -210,7 +207,7 @@ static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
 					   &_nm.m, &_nm.n);
 	} else {
 		ccu_sdm_helper_disable(&nm->common, &nm->sdm);
-		ccu_nm_find_best(parent_rate, rate, &_nm);
+		ccu_nm_find_best(parent_rate, rate, &_nm, &nm->common);
 	}
 
 	spin_lock_irqsave(nm->common.lock, flags);
diff --git a/drivers/clk/sunxi-ng/ccu_nm.h b/drivers/clk/sunxi-ng/ccu_nm.h
index 2904e67f05a8..93c11693574f 100644
--- a/drivers/clk/sunxi-ng/ccu_nm.h
+++ b/drivers/clk/sunxi-ng/ccu_nm.h
@@ -108,7 +108,7 @@ struct ccu_nm {
 		},							\
 	}
 
-#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX(_struct, _name,	\
+#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT(_struct, _name,	\
 						 _parent, _reg,		\
 						 _min_rate, _max_rate,	\
 						 _nshift, _nwidth,	\
@@ -116,7 +116,8 @@ struct ccu_nm {
 						 _frac_en, _frac_sel,	\
 						 _frac_rate_0,		\
 						 _frac_rate_1,		\
-						 _gate, _lock, _flags)	\
+						 _gate, _lock, _flags,	\
+						 _features)		\
 	struct ccu_nm _struct = {					\
 		.enable		= _gate,				\
 		.lock		= _lock,				\
@@ -129,7 +130,7 @@ struct ccu_nm {
 		.max_rate	= _max_rate,				\
 		.common		= {					\
 			.reg		= _reg,				\
-			.features	= CCU_FEATURE_FRACTIONAL,	\
+			.features	= _features,			\
 			.hw.init	= CLK_HW_INIT(_name,		\
 						      _parent,		\
 						      &ccu_nm_ops,	\
@@ -137,6 +138,47 @@ struct ccu_nm {
 		},							\
 	}
 
+#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX(_struct, _name,	\
+						 _parent, _reg,		\
+						 _min_rate, _max_rate,	\
+						 _nshift, _nwidth,	\
+						 _mshift, _mwidth,	\
+						 _frac_en, _frac_sel,	\
+						 _frac_rate_0,		\
+						 _frac_rate_1,		\
+						 _gate, _lock, _flags)	\
+	SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT(_struct, _name,	\
+						_parent, _reg,		\
+						_min_rate, _max_rate,	\
+						_nshift, _nwidth,	\
+						_mshift, _mwidth,	\
+						_frac_en, _frac_sel,	\
+						_frac_rate_0,		\
+						_frac_rate_1,		\
+						_gate, _lock, _flags,	\
+						CCU_FEATURE_FRACTIONAL)
+
+#define SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST(_struct, _name, \
+						 _parent, _reg,		\
+						 _min_rate, _max_rate,	\
+						 _nshift, _nwidth,	\
+						 _mshift, _mwidth,	\
+						 _frac_en, _frac_sel,	\
+						 _frac_rate_0,		\
+						 _frac_rate_1,		\
+						 _gate, _lock, _flags)	\
+	SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT(_struct, _name,	\
+						_parent, _reg,		\
+						_min_rate, _max_rate,	\
+						_nshift, _nwidth,	\
+						_mshift, _mwidth,	\
+						_frac_en, _frac_sel,	\
+						_frac_rate_0,		\
+						_frac_rate_1,		\
+						_gate, _lock, _flags,	\
+						CCU_FEATURE_FRACTIONAL |\
+						CCU_FEATURE_CLOSEST_RATE)
+
 #define SUNXI_CCU_NM_WITH_GATE_LOCK(_struct, _name, _parent, _reg,	\
 				    _nshift, _nwidth,			\
 				    _mshift, _mwidth,			\

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4 07/11] clk: sunxi-ng: nm: Support finding closest rate

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 1559 bytes --]

On Mon, Jul 17, 2023 at 03:34:31PM +0200, Frank Oltmanns wrote:
> Use the helper function ccu_is_better_rate() to determine the rate that
> is closest to the requested rate, thereby supporting rates that are
> higher than the requested rate if the clock uses the
> CCU_FEATURE_CLOSEST_RATE.
> 
> Add the macro SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST which
> sets CCU_FEATURE_CLOSEST_RATE.
> 
> To avoid code duplication, add the macros
> SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT that allows selecting
> arbitrary features and use it in the original
> SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX as well as the newly introduced
> SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST macros.
> 
> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
> ---
>  drivers/clk/sunxi-ng/ccu_nm.c | 11 ++++------
>  drivers/clk/sunxi-ng/ccu_nm.h | 48 ++++++++++++++++++++++++++++++++++++++++---
>  2 files changed, 49 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_nm.c
> index c1fd11542c45..35d00783d748 100644
> --- a/drivers/clk/sunxi-ng/ccu_nm.c
> +++ b/drivers/clk/sunxi-ng/ccu_nm.c
> @@ -28,7 +28,7 @@ static unsigned long ccu_nm_calc_rate(unsigned long parent,
>  }
>  
>  static unsigned long ccu_nm_find_best(unsigned long parent, unsigned long rate,
> -				      struct _ccu_nm *nm)
> +				      struct _ccu_nm *nm, struct ccu_common *common)

The common pointer must be the first argument.

Once fixed,
Acked-by: Maxime Ripard <mripard@kernel.org>

Maxime

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4 07/11] clk: sunxi-ng: nm: Support finding closest rate

[Frank Oltmanns]

On 2023-07-17 at 16:12:30 +0200, Maxime Ripard <mripard@kernel.org> wrote:
> [[PGP Signed Part:Undecided]]
> On Mon, Jul 17, 2023 at 03:34:31PM +0200, Frank Oltmanns wrote:
>> Use the helper function ccu_is_better_rate() to determine the rate that
>> is closest to the requested rate, thereby supporting rates that are
>> higher than the requested rate if the clock uses the
>> CCU_FEATURE_CLOSEST_RATE.
>>
>> Add the macro SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST which
>> sets CCU_FEATURE_CLOSEST_RATE.
>>
>> To avoid code duplication, add the macros
>> SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_FEAT that allows selecting
>> arbitrary features and use it in the original
>> SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX as well as the newly introduced
>> SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST macros.
>>
>> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
>> ---
>>  drivers/clk/sunxi-ng/ccu_nm.c | 11 ++++------
>>  drivers/clk/sunxi-ng/ccu_nm.h | 48 ++++++++++++++++++++++++++++++++++++++++---
>>  2 files changed, 49 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_nm.c
>> index c1fd11542c45..35d00783d748 100644
>> --- a/drivers/clk/sunxi-ng/ccu_nm.c
>> +++ b/drivers/clk/sunxi-ng/ccu_nm.c
>> @@ -28,7 +28,7 @@ static unsigned long ccu_nm_calc_rate(unsigned long parent,
>>  }
>>
>>  static unsigned long ccu_nm_find_best(unsigned long parent, unsigned long rate,
>> -				      struct _ccu_nm *nm)
>> +				      struct _ccu_nm *nm, struct ccu_common *common)
>
> The common pointer must be the first argument.
>

Same question as for patch 08: Should I also pull *nm to the beginning?
If so, do you have a preference on the order of *nm and *common?

Thanks,
  Frank

>
> Once fixed,
> Acked-by: Maxime Ripard <mripard@kernel.org>
>
> Maxime
>
> [[End of PGP Signed Part]]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 08/11] clk: sunxi-ng: nkm: Support finding closest rate

[Frank Oltmanns]

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 by using the helper function ccu_is_better_rate().

Accommodate ccu_mux_helper_determine_rate to this change.

Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_mux.c |  2 +-
 drivers/clk/sunxi-ng/ccu_nkm.c | 18 ++++++++----------
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
index 1d557e323169..3ca695439620 100644
--- a/drivers/clk/sunxi-ng/ccu_mux.c
+++ b/drivers/clk/sunxi-ng/ccu_mux.c
@@ -139,7 +139,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
 			goto out;
 		}
 
-		if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
+		if (ccu_is_better_rate(common, req->rate, tmp_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 793160bc2d47..5439b9351cd7 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -39,6 +39,7 @@ static unsigned long ccu_nkm_optimal_parent_rate(unsigned long rate, unsigned lo
 }
 
 static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struct _ccu_nkm *nkm,
+						       struct ccu_common *common,
 						       unsigned long *parent, unsigned long rate)
 {
 	unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent;
@@ -54,10 +55,8 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struc
 				tmp_parent = clk_hw_round_rate(phw, tmp_parent);
 
 				tmp_rate = tmp_parent * _n * _k / _m;
-				if (tmp_rate > rate)
-					continue;
 
-				if ((rate - tmp_rate) < (rate - best_rate)) {
+				if (ccu_is_better_rate(common, rate, tmp_rate, best_rate)) {
 					best_rate = tmp_rate;
 					best_parent_rate = tmp_parent;
 					best_n = _n;
@@ -78,7 +77,7 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struc
 }
 
 static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
-				       struct _ccu_nkm *nkm)
+				       struct _ccu_nkm *nkm, struct ccu_common *common)
 {
 	unsigned long best_rate = 0;
 	unsigned long best_n = 0, best_k = 0, best_m = 0;
@@ -91,9 +90,7 @@ static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
 
 				tmp_rate = parent * _n * _k / _m;
 
-				if (tmp_rate > rate)
-					continue;
-				if ((rate - tmp_rate) < (rate - best_rate)) {
+				if (ccu_is_better_rate(common, rate, tmp_rate, best_rate)) {
 					best_rate = tmp_rate;
 					best_n = _n;
 					best_k = _k;
@@ -186,9 +183,10 @@ 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);
 	else
-		rate = ccu_nkm_find_best_with_parent_adj(parent_hw, &_nkm, parent_rate, rate);
+		rate = ccu_nkm_find_best_with_parent_adj(parent_hw, &_nkm, &nkm->common,
+							 parent_rate, rate);
 
 	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 		rate /= nkm->fixed_post_div;
@@ -223,7 +221,7 @@ 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);
 
 	spin_lock_irqsave(nkm->common.lock, flags);
 

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4 08/11] clk: sunxi-ng: nkm: Support finding closest rate

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 2648 bytes --]

On Mon, Jul 17, 2023 at 03:34:32PM +0200, Frank Oltmanns wrote:
> 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 by using the helper function ccu_is_better_rate().
> 
> Accommodate ccu_mux_helper_determine_rate to this change.
> 
> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
> ---
>  drivers/clk/sunxi-ng/ccu_mux.c |  2 +-
>  drivers/clk/sunxi-ng/ccu_nkm.c | 18 ++++++++----------
>  2 files changed, 9 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
> index 1d557e323169..3ca695439620 100644
> --- a/drivers/clk/sunxi-ng/ccu_mux.c
> +++ b/drivers/clk/sunxi-ng/ccu_mux.c
> @@ -139,7 +139,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
>  			goto out;
>  		}
>  
> -		if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
> +		if (ccu_is_better_rate(common, req->rate, tmp_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 793160bc2d47..5439b9351cd7 100644
> --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> @@ -39,6 +39,7 @@ static unsigned long ccu_nkm_optimal_parent_rate(unsigned long rate, unsigned lo
>  }
>  
>  static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struct _ccu_nkm *nkm,
> +						       struct ccu_common *common,
>  						       unsigned long *parent, unsigned long rate)
>  {
>  	unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent;
> @@ -54,10 +55,8 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struc
>  				tmp_parent = clk_hw_round_rate(phw, tmp_parent);
>  
>  				tmp_rate = tmp_parent * _n * _k / _m;
> -				if (tmp_rate > rate)
> -					continue;
>  
> -				if ((rate - tmp_rate) < (rate - best_rate)) {
> +				if (ccu_is_better_rate(common, rate, tmp_rate, best_rate)) {
>  					best_rate = tmp_rate;
>  					best_parent_rate = tmp_parent;
>  					best_n = _n;
> @@ -78,7 +77,7 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struc
>  }
>  
>  static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
> -				       struct _ccu_nkm *nkm)
> +				       struct _ccu_nkm *nkm, struct ccu_common *common)

Same comment than on patch 7, common should be first in those two functions.

Once fixed,
Acked-by: Maxime Ripard <mripard@kernel.org>

Maxime

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4 08/11] clk: sunxi-ng: nkm: Support finding closest rate

[Frank Oltmanns]

Hi Maxime,

On 2023-07-17 at 16:14:58 +0200, Maxime Ripard <mripard@kernel.org> wrote:
> [[PGP Signed Part:Undecided]]
> On Mon, Jul 17, 2023 at 03:34:32PM +0200, Frank Oltmanns wrote:
>> 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 by using the helper function ccu_is_better_rate().
>>
>> Accommodate ccu_mux_helper_determine_rate to this change.
>>
>> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
>> ---
>>  drivers/clk/sunxi-ng/ccu_mux.c |  2 +-
>>  drivers/clk/sunxi-ng/ccu_nkm.c | 18 ++++++++----------
>>  2 files changed, 9 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
>> index 1d557e323169..3ca695439620 100644
>> --- a/drivers/clk/sunxi-ng/ccu_mux.c
>> +++ b/drivers/clk/sunxi-ng/ccu_mux.c
>> @@ -139,7 +139,7 @@ int ccu_mux_helper_determine_rate(struct ccu_common *common,
>>  			goto out;
>>  		}
>>
>> -		if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
>> +		if (ccu_is_better_rate(common, req->rate, tmp_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 793160bc2d47..5439b9351cd7 100644
>> --- a/drivers/clk/sunxi-ng/ccu_nkm.c
>> +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
>> @@ -39,6 +39,7 @@ static unsigned long ccu_nkm_optimal_parent_rate(unsigned long rate, unsigned lo
>>  }
>>
>>  static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struct _ccu_nkm *nkm,
>> +						       struct ccu_common *common,
>>  						       unsigned long *parent, unsigned long rate)
>>  {
>>  	unsigned long best_rate = 0, best_parent_rate = *parent, tmp_parent = *parent;
>> @@ -54,10 +55,8 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struc
>>  				tmp_parent = clk_hw_round_rate(phw, tmp_parent);
>>
>>  				tmp_rate = tmp_parent * _n * _k / _m;
>> -				if (tmp_rate > rate)
>> -					continue;
>>
>> -				if ((rate - tmp_rate) < (rate - best_rate)) {
>> +				if (ccu_is_better_rate(common, rate, tmp_rate, best_rate)) {
>>  					best_rate = tmp_rate;
>>  					best_parent_rate = tmp_parent;
>>  					best_n = _n;
>> @@ -78,7 +77,7 @@ static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *phw, struc
>>  }
>>
>>  static unsigned long ccu_nkm_find_best(unsigned long parent, unsigned long rate,
>> -				       struct _ccu_nkm *nkm)
>> +				       struct _ccu_nkm *nkm, struct ccu_common *common)
>
> Same comment than on patch 7, common should be first in those two functions.
>

Ok, I wasn't sure what your expectation is for existing functions. For
ccu_find_best_with_parent_adj the order is:
  1. *phw
  2. *nkm
  3. *common
  4. *parent
  5. rate

We don't have the parent hw in ccu_nkm_find_best. The order prior to
this patch is:
  1. parent
  2. rate
  3. *nkm

We need to add *common to that, so I could add it to the beginning as
per your suggestion:
  1. *common
  2. parent
  3. rate
  4. *nkm

I could also pull *nkm to the beginning (similar to the parent_adj
version):
  4. *nkm
  1. *common
  2. parent
  3. rate

Thanks for your feedback,
  Frank

>
> Once fixed,
> Acked-by: Maxime Ripard <mripard@kernel.org>
>
> Maxime
>
> [[End of PGP Signed Part]]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 09/11] clk: sunxi-ng: mux: Support finding closest rate

[Frank Oltmanns]

When finding the best rate for a mux clock, consider rates that are
higher than the requested rate when CCU_FEATURE_ROUND_CLOSEST is used.
Furthermore, introduce an initialization macro that sets this flag.

Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_mux.c | 13 ++++++++++++-
 drivers/clk/sunxi-ng/ccu_mux.h | 38 +++++++++++++++++++++++++++-----------
 2 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
index 3ca695439620..5edc63b46651 100644
--- a/drivers/clk/sunxi-ng/ccu_mux.c
+++ b/drivers/clk/sunxi-ng/ccu_mux.c
@@ -242,6 +242,17 @@ static int ccu_mux_set_parent(struct clk_hw *hw, u8 index)
 	return ccu_mux_helper_set_parent(&cm->common, &cm->mux, index);
 }
 
+static int ccu_mux_determine_rate(struct clk_hw *hw,
+				  struct clk_rate_request *req)
+{
+	struct ccu_mux *cm = hw_to_ccu_mux(hw);
+
+	if (cm->common.features & CCU_FEATURE_CLOSEST_RATE)
+		return clk_mux_determine_rate_flags(hw, req, CLK_MUX_ROUND_CLOSEST);
+
+	return clk_mux_determine_rate_flags(hw, req, 0);
+}
+
 static unsigned long ccu_mux_recalc_rate(struct clk_hw *hw,
 					 unsigned long parent_rate)
 {
@@ -259,7 +270,7 @@ const struct clk_ops ccu_mux_ops = {
 	.get_parent	= ccu_mux_get_parent,
 	.set_parent	= ccu_mux_set_parent,
 
-	.determine_rate	= __clk_mux_determine_rate,
+	.determine_rate	= ccu_mux_determine_rate,
 	.recalc_rate	= ccu_mux_recalc_rate,
 };
 EXPORT_SYMBOL_NS_GPL(ccu_mux_ops, SUNXI_CCU);
diff --git a/drivers/clk/sunxi-ng/ccu_mux.h b/drivers/clk/sunxi-ng/ccu_mux.h
index 2c1811a445b0..eb1172ebbd94 100644
--- a/drivers/clk/sunxi-ng/ccu_mux.h
+++ b/drivers/clk/sunxi-ng/ccu_mux.h
@@ -46,20 +46,36 @@ struct ccu_mux {
 	struct ccu_common	common;
 };
 
+#define SUNXI_CCU_MUX_TABLE_WITH_GATE_FEAT(_struct, _name, _parents, _table,	\
+				     _reg, _shift, _width, _gate,		\
+				     _flags, _features)				\
+	struct ccu_mux _struct = {						\
+		.enable	= _gate,						\
+		.mux	= _SUNXI_CCU_MUX_TABLE(_shift, _width, _table),		\
+		.common	= {							\
+			.reg		= _reg,					\
+			.hw.init	= CLK_HW_INIT_PARENTS(_name,		\
+							      _parents,		\
+							      &ccu_mux_ops,	\
+							      _flags),		\
+			.features	= _features,				\
+		}								\
+	}
+
+#define SUNXI_CCU_MUX_TABLE_WITH_GATE_CLOSEST(_struct, _name, _parents,	\
+					      _table, _reg, _shift,	\
+					      _width, _gate, _flags)	\
+	SUNXI_CCU_MUX_TABLE_WITH_GATE_FEAT(_struct, _name, _parents,	\
+					   _table, _reg, _shift,	\
+					   _width, _gate, _flags,	\
+					   CCU_FEATURE_CLOSEST_RATE)
+
 #define SUNXI_CCU_MUX_TABLE_WITH_GATE(_struct, _name, _parents, _table,	\
 				     _reg, _shift, _width, _gate,	\
 				     _flags)				\
-	struct ccu_mux _struct = {					\
-		.enable	= _gate,					\
-		.mux	= _SUNXI_CCU_MUX_TABLE(_shift, _width, _table),	\
-		.common	= {						\
-			.reg		= _reg,				\
-			.hw.init	= CLK_HW_INIT_PARENTS(_name,	\
-							      _parents, \
-							      &ccu_mux_ops, \
-							      _flags),	\
-		}							\
-	}
+	SUNXI_CCU_MUX_TABLE_WITH_GATE_FEAT(_struct, _name, _parents,	\
+					   _table, _reg, _shift,	\
+					   _width, _gate, _flags, 0)
 
 #define SUNXI_CCU_MUX_WITH_GATE(_struct, _name, _parents, _reg,		\
 				_shift, _width, _gate, _flags)		\

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4 09/11] clk: sunxi-ng: mux: Support finding closest rate

[Maxime Ripard]

[-- Attachment #1.1: Type: text/plain, Size: 397 bytes --]

On Mon, Jul 17, 2023 at 03:34:33PM +0200, Frank Oltmanns wrote:
> When finding the best rate for a mux clock, consider rates that are
> higher than the requested rate when CCU_FEATURE_ROUND_CLOSEST is used.
> Furthermore, introduce an initialization macro that sets this flag.
> 
> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>

Acked-by: Maxime Ripard <mripard@kernel.org>

Maxime

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

[-- Attachment #2: Type: text/plain, Size: 176 bytes --]

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 10/11] clk: sunxi-ng: div: Support finding closest rate

[Frank Oltmanns]

Add initalization macros for divisor clocks with mux
(SUNXI_CCU_M_WITH_MUX) to support finding the closest rate. This clock
type requires the appropriate flags to be set in the .common structure
(for the mux part of the clock) and the .div part.

Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_div.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/drivers/clk/sunxi-ng/ccu_div.h b/drivers/clk/sunxi-ng/ccu_div.h
index 948e2b0c0c3b..90d49ee8e0cc 100644
--- a/drivers/clk/sunxi-ng/ccu_div.h
+++ b/drivers/clk/sunxi-ng/ccu_div.h
@@ -143,6 +143,26 @@ struct ccu_div {
 		},							\
 	}
 
+#define SUNXI_CCU_M_WITH_MUX_TABLE_GATE_CLOSEST(_struct, _name,		\
+						_parents, _table,	\
+						_reg,			\
+						_mshift, _mwidth,	\
+						_muxshift, _muxwidth,	\
+						_gate, _flags)		\
+	struct ccu_div _struct = {					\
+		.enable	= _gate,					\
+		.div	= _SUNXI_CCU_DIV_FLAGS(_mshift, _mwidth, CLK_DIVIDER_ROUND_CLOSEST), \
+		.mux	= _SUNXI_CCU_MUX_TABLE(_muxshift, _muxwidth, _table), \
+		.common	= {						\
+			.reg		= _reg,				\
+			.hw.init	= CLK_HW_INIT_PARENTS(_name,	\
+							      _parents, \
+							      &ccu_div_ops, \
+							      _flags),	\
+			.features	= CCU_FEATURE_CLOSEST_RATE,	\
+		},							\
+	}
+
 #define SUNXI_CCU_M_WITH_MUX_GATE(_struct, _name, _parents, _reg,	\
 				  _mshift, _mwidth, _muxshift, _muxwidth, \
 				  _gate, _flags)			\
@@ -152,6 +172,16 @@ struct ccu_div {
 					_muxshift, _muxwidth,		\
 					_gate, _flags)
 
+#define SUNXI_CCU_M_WITH_MUX_GATE_CLOSEST(_struct, _name, _parents,	\
+					  _reg, _mshift, _mwidth,	\
+					  _muxshift, _muxwidth,		\
+					  _gate, _flags)		\
+	SUNXI_CCU_M_WITH_MUX_TABLE_GATE_CLOSEST(_struct, _name,		\
+						_parents, NULL,		\
+						_reg, _mshift, _mwidth,	\
+						_muxshift, _muxwidth,	\
+						_gate, _flags)
+
 #define SUNXI_CCU_M_WITH_MUX(_struct, _name, _parents, _reg,		\
 			     _mshift, _mwidth, _muxshift, _muxwidth,	\
 			     _flags)					\

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 11/11] clk: sunxi-ng: a64: select closest rate for pll-video0

[Frank Oltmanns]

Selecting the closest rate for pll-video0 instead of the closest rate
that is less than the requested rate has no downside for this clock,
while allowing for selecting a more suitable rate, e.g. for the
connected panels.

Furthermore, the algorithm that sets an NKM clock's parent benefits from
the closest rate. Without it, the NKM clock's rate might drift away from
the requested rate in the multiple successive calls to
ccu_nkm_determine_rate that the clk framework performs when setting a
clock rate.

Therefore, configure pll-video0 and, in consequence, all of its
descendents to select the closest rate.

Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 33 ++++++++++++++-------------------
 1 file changed, 14 insertions(+), 19 deletions(-)

diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
index a139a5c438d4..73c84d20f3ee 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
@@ -68,7 +68,7 @@ static SUNXI_CCU_NM_WITH_SDM_GATE_LOCK(pll_audio_base_clk, "pll-audio-base",
 				       BIT(28),	/* lock */
 				       CLK_SET_RATE_UNGATE);
 
-static SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX(pll_video0_clk, "pll-video0",
+static SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK_MIN_MAX_CLOSEST(pll_video0_clk, "pll-video0",
 						"osc24M", 0x010,
 						192000000,	/* Minimum rate */
 						1008000000,	/* Maximum rate */
@@ -181,6 +181,7 @@ static struct ccu_nkm pll_mipi_clk = {
 		.hw.init	= CLK_HW_INIT("pll-mipi", "pll-video0",
 					      &ccu_nkm_ops,
 					      CLK_SET_RATE_UNGATE | CLK_SET_RATE_PARENT),
+		.features	= CCU_FEATURE_CLOSEST_RATE,
 	},
 };
 
@@ -531,24 +532,18 @@ static SUNXI_CCU_M_WITH_MUX_GATE(de_clk, "de", de_parents,
 
 static const char * const tcon0_parents[] = { "pll-mipi", "pll-video0-2x" };
 static const u8 tcon0_table[] = { 0, 2, };
-static SUNXI_CCU_MUX_TABLE_WITH_GATE(tcon0_clk, "tcon0", tcon0_parents,
+static SUNXI_CCU_MUX_TABLE_WITH_GATE_CLOSEST(tcon0_clk, "tcon0", tcon0_parents,
 				     tcon0_table, 0x118, 24, 3, BIT(31),
 				     CLK_SET_RATE_PARENT);
 
 static const char * const tcon1_parents[] = { "pll-video0", "pll-video1" };
 static const u8 tcon1_table[] = { 0, 2, };
-static struct ccu_div tcon1_clk = {
-	.enable		= BIT(31),
-	.div		= _SUNXI_CCU_DIV(0, 4),
-	.mux		= _SUNXI_CCU_MUX_TABLE(24, 2, tcon1_table),
-	.common		= {
-		.reg		= 0x11c,
-		.hw.init	= CLK_HW_INIT_PARENTS("tcon1",
-						      tcon1_parents,
-						      &ccu_div_ops,
-						      CLK_SET_RATE_PARENT),
-	},
-};
+static SUNXI_CCU_M_WITH_MUX_TABLE_GATE_CLOSEST(tcon1_clk, "tcon1", tcon1_parents,
+					       tcon1_table, 0x11c,
+					       0, 4,	/* M */
+					       24, 2,	/* mux */
+					       BIT(31),	/* gate */
+					       CLK_SET_RATE_PARENT);
 
 static const char * const deinterlace_parents[] = { "pll-periph0", "pll-periph1" };
 static SUNXI_CCU_M_WITH_MUX_GATE(deinterlace_clk, "deinterlace", deinterlace_parents,
@@ -578,8 +573,8 @@ static SUNXI_CCU_GATE(avs_clk,		"avs",		"osc24M",
 		      0x144, BIT(31), 0);
 
 static const char * const hdmi_parents[] = { "pll-video0", "pll-video1" };
-static SUNXI_CCU_M_WITH_MUX_GATE(hdmi_clk, "hdmi", hdmi_parents,
-				 0x150, 0, 4, 24, 2, BIT(31), CLK_SET_RATE_PARENT);
+static SUNXI_CCU_M_WITH_MUX_GATE_CLOSEST(hdmi_clk, "hdmi", hdmi_parents,
+					 0x150, 0, 4, 24, 2, BIT(31), CLK_SET_RATE_PARENT);
 
 static SUNXI_CCU_GATE(hdmi_ddc_clk,	"hdmi-ddc",	"osc24M",
 		      0x154, BIT(31), 0);
@@ -591,9 +586,9 @@ static SUNXI_CCU_M_WITH_MUX_GATE(mbus_clk, "mbus", mbus_parents,
 
 static const char * const dsi_dphy_parents[] = { "pll-video0", "pll-periph0" };
 static const u8 dsi_dphy_table[] = { 0, 2, };
-static SUNXI_CCU_M_WITH_MUX_TABLE_GATE(dsi_dphy_clk, "dsi-dphy",
-				       dsi_dphy_parents, dsi_dphy_table,
-				       0x168, 0, 4, 8, 2, BIT(15), CLK_SET_RATE_PARENT);
+static SUNXI_CCU_M_WITH_MUX_TABLE_GATE_CLOSEST(dsi_dphy_clk, "dsi-dphy",
+					       dsi_dphy_parents, dsi_dphy_table,
+					       0x168, 0, 4, 8, 2, BIT(15), CLK_SET_RATE_PARENT);
 
 static SUNXI_CCU_M_WITH_GATE(gpu_clk, "gpu", "pll-gpu",
 			     0x1a0, 0, 3, BIT(31), CLK_SET_RATE_PARENT);

-- 
2.41.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Re: [PATCH v4 11/11] clk: sunxi-ng: a64: select closest rate for pll-video0

[Maxime Ripard]

On Mon, 17 Jul 2023 15:34:35 +0200, Frank Oltmanns wrote:
> Selecting the closest rate for pll-video0 instead of the closest rate
> that is less than the requested rate has no downside for this clock,
> while allowing for selecting a more suitable rate, e.g. for the
> connected panels.
> 
> 
> [ ... ]

Acked-by: Maxime Ripard <mripard@kernel.org>

Thanks!
Maxime

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel