diff mbox

[2/10] clk: sunxi-ng: nkm: Deal with fixed post dividers

Message ID f8333c3a1f3308fcebd87bfc3710ce605f9bb595.1478625788.git-series.maxime.ripard@free-electrons.com (mailing list archive)
State New, archived
Headers show

Commit Message

Maxime Ripard Nov. 8, 2016, 5:23 p.m. UTC 
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
 drivers/clk/sunxi-ng/ccu_nkm.c | 17 ++++++++++++++---
 drivers/clk/sunxi-ng/ccu_nkm.h |  2 ++
 2 files changed, 16 insertions(+), 3 deletions(-)

Comments

Chen-Yu Tsai Nov. 13, 2016, 3:48 a.m. UTC | #1 
On Wed, Nov 9, 2016 at 1:23 AM, Maxime Ripard
<maxime.ripard@free-electrons.com> wrote:

It'd be better if you mentioned what clock needs this.

> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
>  drivers/clk/sunxi-ng/ccu_nkm.c | 17 ++++++++++++++---
>  drivers/clk/sunxi-ng/ccu_nkm.h |  2 ++
>  2 files changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
> index 9b840a47a94d..fd3c6a9d987c 100644
> --- a/drivers/clk/sunxi-ng/ccu_nkm.c
> +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
> @@ -75,7 +75,7 @@ static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
>                                         unsigned long parent_rate)
>  {
>         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
> -       unsigned long n, m, k;
> +       unsigned long rate, n, m, k;
>         u32 reg;
>
>         reg = readl(nkm->common.base + nkm->common.reg);
> @@ -89,7 +89,11 @@ static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
>         m = reg >> nkm->m.shift;
>         m &= (1 << nkm->m.width) - 1;
>
> -       return parent_rate * (n + 1) * (k + 1) / (m + 1);
> +       rate = parent_rate * (n + 1) * (k + 1) / (m + 1);
> +       if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
> +               rate /= nkm->fixed_post_div;
> +
> +       return rate;
>  }
>
>  static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
> @@ -100,6 +104,9 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
>         struct ccu_nkm *nkm = data;
>         struct _ccu_nkm _nkm;
>
> +       if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
> +               rate *= nkm->fixed_post_div;
> +
>         _nkm.min_n = nkm->n.min;
>         _nkm.max_n = 1 << nkm->n.width;
>         _nkm.min_k = nkm->k.min;
> @@ -109,7 +116,11 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
>
>         ccu_nkm_find_best(parent_rate, rate, &_nkm);
>
> -       return parent_rate * _nkm.n * _nkm.k / _nkm.m;
> +       rate = parent_rate * _nkm.n * _nkm.k / _nkm.m;
> +       if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
> +               rate = rate / nkm->fixed_post_div;
> +
> +       return rate;
>  }
>

You also need to handle this in the set_rate callback. You might need
to read back
the parent index value to determine if the post divider applies, as
this clock supports
a mux. Or don't support mux + post-div, and leave a TODO note.

ChenYu

>  static int ccu_nkm_determine_rate(struct clk_hw *hw,
> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.h b/drivers/clk/sunxi-ng/ccu_nkm.h
> index 34580894f4d1..0f1dbca25719 100644
> --- a/drivers/clk/sunxi-ng/ccu_nkm.h
> +++ b/drivers/clk/sunxi-ng/ccu_nkm.h
> @@ -32,6 +32,8 @@ struct ccu_nkm {
>         struct ccu_mult_internal        n;
>         struct ccu_mult_internal        k;
>         struct ccu_div_internal         m;
> +
> +       unsigned int            fixed_post_div;
>         struct ccu_mux_internal mux;
>
>         struct ccu_common       common;
> --
> git-series 0.8.11
Chen-Yu Tsai Nov. 13, 2016, 3:49 a.m. UTC | #2 
On Sun, Nov 13, 2016 at 11:48 AM, Chen-Yu Tsai <wens@csie.org> wrote:
> On Wed, Nov 9, 2016 at 1:23 AM, Maxime Ripard
> <maxime.ripard@free-electrons.com> wrote:
>
> It'd be better if you mentioned what clock needs this.
>
>> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
>> ---
>>  drivers/clk/sunxi-ng/ccu_nkm.c | 17 ++++++++++++++---
>>  drivers/clk/sunxi-ng/ccu_nkm.h |  2 ++
>>  2 files changed, 16 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
>> index 9b840a47a94d..fd3c6a9d987c 100644
>> --- a/drivers/clk/sunxi-ng/ccu_nkm.c
>> +++ b/drivers/clk/sunxi-ng/ccu_nkm.c
>> @@ -75,7 +75,7 @@ static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
>>                                         unsigned long parent_rate)
>>  {
>>         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
>> -       unsigned long n, m, k;
>> +       unsigned long rate, n, m, k;
>>         u32 reg;
>>
>>         reg = readl(nkm->common.base + nkm->common.reg);
>> @@ -89,7 +89,11 @@ static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
>>         m = reg >> nkm->m.shift;
>>         m &= (1 << nkm->m.width) - 1;
>>
>> -       return parent_rate * (n + 1) * (k + 1) / (m + 1);
>> +       rate = parent_rate * (n + 1) * (k + 1) / (m + 1);
>> +       if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
>> +               rate /= nkm->fixed_post_div;
>> +
>> +       return rate;
>>  }
>>
>>  static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
>> @@ -100,6 +104,9 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
>>         struct ccu_nkm *nkm = data;
>>         struct _ccu_nkm _nkm;
>>
>> +       if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
>> +               rate *= nkm->fixed_post_div;
>> +
>>         _nkm.min_n = nkm->n.min;
>>         _nkm.max_n = 1 << nkm->n.width;
>>         _nkm.min_k = nkm->k.min;
>> @@ -109,7 +116,11 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
>>
>>         ccu_nkm_find_best(parent_rate, rate, &_nkm);
>>
>> -       return parent_rate * _nkm.n * _nkm.k / _nkm.m;
>> +       rate = parent_rate * _nkm.n * _nkm.k / _nkm.m;
>> +       if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
>> +               rate = rate / nkm->fixed_post_div;
>> +
>> +       return rate;
>>  }
>>
>
> You also need to handle this in the set_rate callback. You might need
> to read back
> the parent index value to determine if the post divider applies, as
> this clock supports
> a mux. Or don't support mux + post-div, and leave a TODO note.

Was thinking pre-dividers... sorry. Please ignore the second parent
index part.

ChenYu

>
> ChenYu
>
>>  static int ccu_nkm_determine_rate(struct clk_hw *hw,
>> diff --git a/drivers/clk/sunxi-ng/ccu_nkm.h b/drivers/clk/sunxi-ng/ccu_nkm.h
>> index 34580894f4d1..0f1dbca25719 100644
>> --- a/drivers/clk/sunxi-ng/ccu_nkm.h
>> +++ b/drivers/clk/sunxi-ng/ccu_nkm.h
>> @@ -32,6 +32,8 @@ struct ccu_nkm {
>>         struct ccu_mult_internal        n;
>>         struct ccu_mult_internal        k;
>>         struct ccu_div_internal         m;
>> +
>> +       unsigned int            fixed_post_div;
>>         struct ccu_mux_internal mux;
>>
>>         struct ccu_common       common;
>> --
>> git-series 0.8.11
diff mbox

Patch

diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
index 9b840a47a94d..fd3c6a9d987c 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -75,7 +75,7 @@  static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
 					unsigned long parent_rate)
 {
 	struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
-	unsigned long n, m, k;
+	unsigned long rate, n, m, k;
 	u32 reg;
 
 	reg = readl(nkm->common.base + nkm->common.reg);
@@ -89,7 +89,11 @@  static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
 	m = reg >> nkm->m.shift;
 	m &= (1 << nkm->m.width) - 1;
 
-	return parent_rate * (n + 1) * (k + 1) / (m + 1);
+	rate = parent_rate * (n + 1) * (k + 1) / (m + 1);
+	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+		rate /= nkm->fixed_post_div;
+
+	return rate;
 }
 
 static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
@@ -100,6 +104,9 @@  static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
 	struct ccu_nkm *nkm = data;
 	struct _ccu_nkm _nkm;
 
+	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+		rate *= nkm->fixed_post_div;
+
 	_nkm.min_n = nkm->n.min;
 	_nkm.max_n = 1 << nkm->n.width;
 	_nkm.min_k = nkm->k.min;
@@ -109,7 +116,11 @@  static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
 
 	ccu_nkm_find_best(parent_rate, rate, &_nkm);
 
-	return parent_rate * _nkm.n * _nkm.k / _nkm.m;
+	rate = parent_rate * _nkm.n * _nkm.k / _nkm.m;
+	if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
+		rate = rate / nkm->fixed_post_div;
+
+	return rate;
 }
 
 static int ccu_nkm_determine_rate(struct clk_hw *hw,
diff --git a/drivers/clk/sunxi-ng/ccu_nkm.h b/drivers/clk/sunxi-ng/ccu_nkm.h
index 34580894f4d1..0f1dbca25719 100644
--- a/drivers/clk/sunxi-ng/ccu_nkm.h
+++ b/drivers/clk/sunxi-ng/ccu_nkm.h
@@ -32,6 +32,8 @@  struct ccu_nkm {
 	struct ccu_mult_internal	n;
 	struct ccu_mult_internal	k;
 	struct ccu_div_internal		m;
+
+	unsigned int		fixed_post_div;
 	struct ccu_mux_internal	mux;
 
 	struct ccu_common	common;