diff mbox series

[v5,02/11] clk: sunxi-ng: nkm: consider alternative parent rates when determining rate

Message ID 20230806-pll-mipi_set_rate_parent-v5-2-db4f5ca33fc3@oltmanns.dev
State New
Headers
Series clk: sunxi-ng: Consider alternative parent rates when determining NKM clock rate |

Commit Message

Frank Oltmanns Aug. 6, 2023, 1:06 p.m. UTC 
  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.

Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
---
 drivers/clk/sunxi-ng/ccu_nkm.c | 45 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

Comments

Jernej Škrabec Aug. 6, 2023, 1:32 p.m. UTC | #1 
Dne nedelja, 06. avgust 2023 ob 15:06:47 CEST je Frank Oltmanns napisal(a):
> 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.
> 
> Acked-by: Maxime Ripard <mripard@kernel.org>
> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
> ---
>  drivers/clk/sunxi-ng/ccu_nkm.c | 45
> +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 44
> insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> index f267142e58b3..ea1b77e9b57f 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>

Why do you need above include?

Best regards,
Jernej

> 
>  #include "ccu_gate.h"
>  #include "ccu_nkm.h"
> @@ -16,6 +17,45 @@ struct _ccu_nkm {
>  	unsigned long	m, min_m, max_m;
>  };
> 
> +static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw
> *parent_hw, +						
       unsigned long *parent, unsigned long rate,
> +						       
struct _ccu_nkm *nkm)
> +{
> +	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(parent_hw, 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 +164,10 @@ 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, 
parent_rate, rate,
> &_nkm);
> 
>  	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
>  		rate /= nkm->fixed_post_div;
Frank Oltmanns Aug. 6, 2023, 1:57 p.m. UTC | #2 
On 2023-08-06 at 15:32:29 +0200, Jernej Škrabec <jernej.skrabec@gmail.com> wrote:
> Dne nedelja, 06. avgust 2023 ob 15:06:47 CEST je Frank Oltmanns napisal(a):
>> 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.
>>
>> Acked-by: Maxime Ripard <mripard@kernel.org>
>> Signed-off-by: Frank Oltmanns <frank@oltmanns.dev>
>> ---
>>  drivers/clk/sunxi-ng/ccu_nkm.c | 45
>> +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 44
>> insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
>> index f267142e58b3..ea1b77e9b57f 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>
>
> Why do you need above include?

It's not needed. It's a leftover from an earlier version. I'll remove it
in v6.

Thank you for your review,
  Frank

>
> Best regards,
> Jernej
>
>>
>>  #include "ccu_gate.h"
>>  #include "ccu_nkm.h"
>> @@ -16,6 +17,45 @@ struct _ccu_nkm {
>>  	unsigned long	m, min_m, max_m;
>>  };
>>
>> +static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw
>> *parent_hw, +
>        unsigned long *parent, unsigned long rate,
>> +
> struct _ccu_nkm *nkm)
>> +{
>> +	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(parent_hw, 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 +164,10 @@ 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,
> parent_rate, rate,
>> &_nkm);
>>
>>  	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
>>  		rate /= nkm->fixed_post_div;
diff mbox series

Patch

diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
index f267142e58b3..ea1b77e9b57f 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 +17,45 @@  struct _ccu_nkm {
 	unsigned long	m, min_m, max_m;
 };
 
+static unsigned long ccu_nkm_find_best_with_parent_adj(struct clk_hw *parent_hw,
+						       unsigned long *parent, unsigned long rate,
+						       struct _ccu_nkm *nkm)
+{
+	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(parent_hw, 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 +164,10 @@  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, parent_rate, rate, &_nkm);
 
 	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 		rate /= nkm->fixed_post_div;