[PATCH v2] drm/msm/dsi: Use division result from div_u64_rem in 7nm and 14nm PLL

[PATCH v2] drm/msm/dsi: Use division result from div_u64_rem in 7nm and 14nm PLL

[Marijn Suijten]

div_u64_rem provides the result of the division and additionally the
remainder; don't use this function to solely calculate the remainder
while calculating the division again with div_u64.

A similar improvement was applied earlier to the 10nm pll in
5c191fef4ce2 ("drm/msm/dsi_pll_10nm: Fix dividing the same numbers
twice").

Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
---

Changes in v2:
- Corrected two typos in the first commit-message sentence.

 drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c | 4 +---
 drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c  | 4 +---
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c
index 9a959a5dcc1e..de3c6556a587 100644
--- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c
+++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c
@@ -215,9 +215,7 @@ static void pll_14nm_dec_frac_calc(struct dsi_pll_14nm *pll, struct dsi_pll_conf
 	DBG("vco_clk_rate=%lld ref_clk_rate=%lld", vco_clk_rate, fref);

 	dec_start_multiple = div_u64(vco_clk_rate * multiplier, fref);
-	div_u64_rem(dec_start_multiple, multiplier, &div_frac_start);
-
-	dec_start = div_u64(dec_start_multiple, multiplier);
+	dec_start = div_u64_rem(dec_start_multiple, multiplier, &div_frac_start);

 	pconf->dec_start = (u32)dec_start;
 	pconf->div_frac_start = div_frac_start;
diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
index 9f7c408325ba..36eb6109cb88 100644
--- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
+++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
@@ -114,9 +114,7 @@ static void dsi_pll_calc_dec_frac(struct dsi_pll_7nm *pll, struct dsi_pll_config

 	multiplier = 1 << FRAC_BITS;
 	dec_multiple = div_u64(pll_freq * multiplier, divider);
-	div_u64_rem(dec_multiple, multiplier, &frac);
-
-	dec = div_u64(dec_multiple, multiplier);
+	dec = div_u64_rem(dec_multiple, multiplier, &frac);

 	if (!(pll->phy->cfg->quirks & DSI_PHY_7NM_QUIRK_V4_1))
 		config->pll_clock_inverters = 0x28;
--
2.33.0

Re: [PATCH v2] drm/msm/dsi: Use division result from div_u64_rem in 7nm and 14nm PLL

[AngeloGioacchino Del Regno]

> div_u64_rem provides the result of the division and additionally the
> remainder; don't use this function to solely calculate the remainder
> while calculating the division again with div_u64.
> 
> A similar improvement was applied earlier to the 10nm pll in
> 5c191fef4ce2 ("drm/msm/dsi_pll_10nm: Fix dividing the same numbers
> twice").
> 
> Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
> ---
> 
> Changes in v2:
> - Corrected two typos in the first commit-message sentence.
> 

Reviewed-By: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>

Re: [Freedreno] [PATCH v2] drm/msm/dsi: Use division result from div_u64_rem in 7nm and 14nm PLL

[abhinavk]

On 2021-10-11 13:16, Marijn Suijten wrote:
> div_u64_rem provides the result of the division and additionally the
> remainder; don't use this function to solely calculate the remainder
> while calculating the division again with div_u64.
> 
> A similar improvement was applied earlier to the 10nm pll in
> 5c191fef4ce2 ("drm/msm/dsi_pll_10nm: Fix dividing the same numbers
> twice").
> 
> Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
> ---
> 
> Changes in v2:
> - Corrected two typos in the first commit-message sentence.
> 
>  drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c | 4 +---
>  drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c  | 4 +---
>  2 files changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c
> b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c
> index 9a959a5dcc1e..de3c6556a587 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c
> @@ -215,9 +215,7 @@ static void pll_14nm_dec_frac_calc(struct
> dsi_pll_14nm *pll, struct dsi_pll_conf
>  	DBG("vco_clk_rate=%lld ref_clk_rate=%lld", vco_clk_rate, fref);
> 
>  	dec_start_multiple = div_u64(vco_clk_rate * multiplier, fref);
> -	div_u64_rem(dec_start_multiple, multiplier, &div_frac_start);
> -
> -	dec_start = div_u64(dec_start_multiple, multiplier);
> +	dec_start = div_u64_rem(dec_start_multiple, multiplier, 
> &div_frac_start);
> 
>  	pconf->dec_start = (u32)dec_start;
>  	pconf->div_frac_start = div_frac_start;
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> index 9f7c408325ba..36eb6109cb88 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c
> @@ -114,9 +114,7 @@ static void dsi_pll_calc_dec_frac(struct
> dsi_pll_7nm *pll, struct dsi_pll_config
> 
>  	multiplier = 1 << FRAC_BITS;
>  	dec_multiple = div_u64(pll_freq * multiplier, divider);
> -	div_u64_rem(dec_multiple, multiplier, &frac);
> -
> -	dec = div_u64(dec_multiple, multiplier);
> +	dec = div_u64_rem(dec_multiple, multiplier, &frac);
> 
>  	if (!(pll->phy->cfg->quirks & DSI_PHY_7NM_QUIRK_V4_1))
>  		config->pll_clock_inverters = 0x28;
> --
> 2.33.0

Re: [PATCH v2] drm/msm/dsi: Use division result from div_u64_rem in 7nm and 14nm PLL

[Stephen Boyd]

Quoting Marijn Suijten (2021-10-11 13:16:40)
> div_u64_rem provides the result of the division and additionally the
> remainder; don't use this function to solely calculate the remainder
> while calculating the division again with div_u64.
>
> A similar improvement was applied earlier to the 10nm pll in
> 5c191fef4ce2 ("drm/msm/dsi_pll_10nm: Fix dividing the same numbers
> twice").
>
> Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>