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 <[email protected]>
---
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
> 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 <[email protected]>
> ---
>
> Changes in v2:
> - Corrected two typos in the first commit-message sentence.
>
Reviewed-By: AngeloGioacchino Del Regno <[email protected]>
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 <[email protected]>
Reviewed-by: Abhinav Kumar <[email protected]>
> ---
>
> 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
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 <[email protected]>
> ---
Reviewed-by: Stephen Boyd <[email protected]>