diff mbox

[v2,1/2] clk: meson: mpll: add round closest support

Message ID 20180515163652.19980-2-jbrunet@baylibre.com (mailing list archive)
State Not Applicable
Headers show

Commit Message

Jerome Brunet May 15, 2018, 4:36 p.m. UTC
Allow the mpll driver to round the requested rate up if
CLK_MESON_MPLL_ROUND_CLOSEST is set and it provides a rate closer to the
requested rate.

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
 drivers/clk/meson/clk-mpll.c | 24 +++++++++++++++++++-----
 drivers/clk/meson/clkc.h     |  3 +++
 2 files changed, 22 insertions(+), 5 deletions(-)

Comments

Neil Armstrong May 15, 2018, 4:45 p.m. UTC | #1
On 15/05/2018 18:36, Jerome Brunet wrote:
> Allow the mpll driver to round the requested rate up if
> CLK_MESON_MPLL_ROUND_CLOSEST is set and it provides a rate closer to the
> requested rate.
> 
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> ---
>  drivers/clk/meson/clk-mpll.c | 24 +++++++++++++++++++-----
>  drivers/clk/meson/clkc.h     |  3 +++
>  2 files changed, 22 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/clk/meson/clk-mpll.c b/drivers/clk/meson/clk-mpll.c
> index 0df1227b65b3..d233549de244 100644
> --- a/drivers/clk/meson/clk-mpll.c
> +++ b/drivers/clk/meson/clk-mpll.c
> @@ -89,10 +89,23 @@ static long rate_from_params(unsigned long parent_rate,
>  static void params_from_rate(unsigned long requested_rate,
>  			     unsigned long parent_rate,
>  			     unsigned int *sdm,
> -			     unsigned int *n2)
> +			     unsigned int *n2,
> +			     u8 flags)
>  {
>  	uint64_t div = parent_rate;
> -	unsigned long rem = do_div(div, requested_rate);
> +	uint64_t frac = do_div(div, requested_rate);
> +
> +	frac *= SDM_DEN;
> +
> +	if (flags & CLK_MESON_MPLL_ROUND_CLOSEST)
> +		*sdm = DIV_ROUND_CLOSEST_ULL(frac, requested_rate);
> +	else
> +		*sdm = DIV_ROUND_UP_ULL(frac, requested_rate);
> +
> +	if (*sdm == SDM_DEN) {
> +		*sdm = 0;
> +		div += 1;
> +	}
>  
>  	if (div < N2_MIN) {
>  		*n2 = N2_MIN;
> @@ -102,7 +115,6 @@ static void params_from_rate(unsigned long requested_rate,
>  		*sdm = SDM_DEN - 1;
>  	} else {
>  		*n2 = div;
> -		*sdm = DIV_ROUND_UP_ULL((u64)rem * SDM_DEN, requested_rate);
>  	}
>  }
>  
> @@ -125,9 +137,11 @@ static long mpll_round_rate(struct clk_hw *hw,
>  			    unsigned long rate,
>  			    unsigned long *parent_rate)
>  {
> +	struct clk_regmap *clk = to_clk_regmap(hw);
> +	struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
>  	unsigned int sdm, n2;
>  
> -	params_from_rate(rate, *parent_rate, &sdm, &n2);
> +	params_from_rate(rate, *parent_rate, &sdm, &n2, mpll->flags);
>  	return rate_from_params(*parent_rate, sdm, n2);
>  }
>  
> @@ -140,7 +154,7 @@ static int mpll_set_rate(struct clk_hw *hw,
>  	unsigned int sdm, n2;
>  	unsigned long flags = 0;
>  
> -	params_from_rate(rate, parent_rate, &sdm, &n2);
> +	params_from_rate(rate, parent_rate, &sdm, &n2, mpll->flags);
>  
>  	if (mpll->lock)
>  		spin_lock_irqsave(mpll->lock, flags);
> diff --git a/drivers/clk/meson/clkc.h b/drivers/clk/meson/clkc.h
> index 8fe73c4edca8..8cc265cd3d2b 100644
> --- a/drivers/clk/meson/clkc.h
> +++ b/drivers/clk/meson/clkc.h
> @@ -97,8 +97,11 @@ struct meson_clk_mpll_data {
>  	struct parm ssen;
>  	struct parm misc;
>  	spinlock_t *lock;
> +	u8 flags;
>  };
>  
> +#define CLK_MESON_MPLL_ROUND_CLOSEST	BIT(0)
> +
>  struct meson_clk_audio_div_data {
>  	struct parm div;
>  	u8 flags;
> 

Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Martin Blumenstingl May 21, 2018, 9:18 a.m. UTC | #2
On Tue, May 15, 2018 at 6:36 PM, Jerome Brunet <jbrunet@baylibre.com> wrote:
> Allow the mpll driver to round the requested rate up if
> CLK_MESON_MPLL_ROUND_CLOSEST is set and it provides a rate closer to the
> requested rate.
>
> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Acked-by: Martin Blumenstingl<martin.blumenstingl@googlemail.com>


I gave it a quick spin on Odroid-C1 (which uses an RGMII Ethernet PHY
and the RGMII TX clock is supplied by MPLL2). the clock tree looks
fine and Ethernet is still working:
          mpll2_div                   1        1        0   249999701
        0 0
            mpll2                    1        1        0   249999701
       0 0
               c9410000.ethernet#m250_sel       1        1        0
249999701          0 0
                  c9410000.ethernet#m250_div       1        1        0
  249999701          0 0
                     c9410000.ethernet#fixed_div2       1        1
   0   124999850          0 0
                        c9410000.ethernet#rgmii_tx_en       1        1
       0   124999850          0 0
Jerome Brunet May 21, 2018, 9:32 a.m. UTC | #3
On Mon, 2018-05-21 at 11:18 +0200, Martin Blumenstingl wrote:
> On Tue, May 15, 2018 at 6:36 PM, Jerome Brunet <jbrunet@baylibre.com> wrote:
> > Allow the mpll driver to round the requested rate up if
> > CLK_MESON_MPLL_ROUND_CLOSEST is set and it provides a rate closer to the
> > requested rate.
> > 
> > Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> 
> Acked-by: Martin Blumenstingl<martin.blumenstingl@googlemail.com>

Thx for the feedback Martin.
Applied.
diff mbox

Patch

diff --git a/drivers/clk/meson/clk-mpll.c b/drivers/clk/meson/clk-mpll.c
index 0df1227b65b3..d233549de244 100644
--- a/drivers/clk/meson/clk-mpll.c
+++ b/drivers/clk/meson/clk-mpll.c
@@ -89,10 +89,23 @@  static long rate_from_params(unsigned long parent_rate,
 static void params_from_rate(unsigned long requested_rate,
 			     unsigned long parent_rate,
 			     unsigned int *sdm,
-			     unsigned int *n2)
+			     unsigned int *n2,
+			     u8 flags)
 {
 	uint64_t div = parent_rate;
-	unsigned long rem = do_div(div, requested_rate);
+	uint64_t frac = do_div(div, requested_rate);
+
+	frac *= SDM_DEN;
+
+	if (flags & CLK_MESON_MPLL_ROUND_CLOSEST)
+		*sdm = DIV_ROUND_CLOSEST_ULL(frac, requested_rate);
+	else
+		*sdm = DIV_ROUND_UP_ULL(frac, requested_rate);
+
+	if (*sdm == SDM_DEN) {
+		*sdm = 0;
+		div += 1;
+	}
 
 	if (div < N2_MIN) {
 		*n2 = N2_MIN;
@@ -102,7 +115,6 @@  static void params_from_rate(unsigned long requested_rate,
 		*sdm = SDM_DEN - 1;
 	} else {
 		*n2 = div;
-		*sdm = DIV_ROUND_UP_ULL((u64)rem * SDM_DEN, requested_rate);
 	}
 }
 
@@ -125,9 +137,11 @@  static long mpll_round_rate(struct clk_hw *hw,
 			    unsigned long rate,
 			    unsigned long *parent_rate)
 {
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
 	unsigned int sdm, n2;
 
-	params_from_rate(rate, *parent_rate, &sdm, &n2);
+	params_from_rate(rate, *parent_rate, &sdm, &n2, mpll->flags);
 	return rate_from_params(*parent_rate, sdm, n2);
 }
 
@@ -140,7 +154,7 @@  static int mpll_set_rate(struct clk_hw *hw,
 	unsigned int sdm, n2;
 	unsigned long flags = 0;
 
-	params_from_rate(rate, parent_rate, &sdm, &n2);
+	params_from_rate(rate, parent_rate, &sdm, &n2, mpll->flags);
 
 	if (mpll->lock)
 		spin_lock_irqsave(mpll->lock, flags);
diff --git a/drivers/clk/meson/clkc.h b/drivers/clk/meson/clkc.h
index 8fe73c4edca8..8cc265cd3d2b 100644
--- a/drivers/clk/meson/clkc.h
+++ b/drivers/clk/meson/clkc.h
@@ -97,8 +97,11 @@  struct meson_clk_mpll_data {
 	struct parm ssen;
 	struct parm misc;
 	spinlock_t *lock;
+	u8 flags;
 };
 
+#define CLK_MESON_MPLL_ROUND_CLOSEST	BIT(0)
+
 struct meson_clk_audio_div_data {
 	struct parm div;
 	u8 flags;