Re: [PATCH v5 07/12] phy: rockchip: samsung-hdptx: Avoid Hz<->hHz unit conversion overhead

From: David Laight
Date: Sun Mar 09 2025 - 10:50:04 EST

On Sun, 9 Mar 2025 12:13:32 +0200
Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx> wrote:

> On 3/9/25 11:22 AM, Dmitry Baryshkov wrote:
> > On Sat, 8 Mar 2025 at 14:21, Cristian Ciocaltea
> > <cristian.ciocaltea@xxxxxxxxxxxxx> wrote:
> >>
> >> The ropll_tmds_cfg table used to identify the configuration params for
> >> the supported rates expects the search key, i.e. bit_rate member of
> >> struct ropll_config, to be provided in hHz rather than Hz (1 hHz = 100
> >> Hz). This requires multiple conversions between these units being
> >> performed at runtime.
> >>
> >> Improve implementation clarity and efficiency by consistently using the
> >> Hz unit throughout driver's internal data structures and functions.
> >> Also rename the rather misleading struct member.
> >>
> >> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>
> >> ---
> >> drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c | 79 +++++++++++------------
> >> 1 file changed, 39 insertions(+), 40 deletions(-)
> >>
> >> diff --git a/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c b/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
> >> index 2bf525514c1991a1299265d12e1e85f66333c604..e58a01bdb3ce82d66acdcb02c06de2816288b574 100644
> >> --- a/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
> >> +++ b/drivers/phy/rockchip/phy-rockchip-samsung-hdptx.c
> >> @@ -330,7 +330,7 @@ enum dp_link_rate {
> >> };
> >>
> >> struct ropll_config {
> >> - u32 bit_rate;
> >> + u32 rate;
> >
> > unsigned long long, please, to match the tmds_char_rate type.

Isn't 'bit_rate' more descriptive?
But maybe rate_hz to make the units more obvious.

If the max frequency might get near 4Gz then the you need something
bigger that u32 - which might it used hectaHz (a prefix that is pretty much only
used with areas of land!)
Being more explicit with u64 (rather than 'long long') may be better.
Certainly less typing.

David



> >
> >> u8 pms_mdiv;
> >> u8 pms_mdiv_afc;
> >> u8 pms_pdiv;
> >> @@ -410,45 +410,45 @@ struct rk_hdptx_phy {
> >> };
> >>
> >> static const struct ropll_config ropll_tmds_cfg[] = {
> >> - { 5940000, 124, 124, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> + { 594000000, 124, 124, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >
> > Use ULL suffix
> >
> >> 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 3712500, 155, 155, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> + { 371250000, 155, 155, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 2970000, 124, 124, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> + { 297000000, 124, 124, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 1620000, 135, 135, 1, 1, 3, 1, 1, 0, 1, 1, 1, 1, 4, 0, 3, 5, 5, 0x10,
> >> + { 162000000, 135, 135, 1, 1, 3, 1, 1, 0, 1, 1, 1, 1, 4, 0, 3, 5, 5, 0x10,
> >> 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 1856250, 155, 155, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> + { 185625000, 155, 155, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 1540000, 193, 193, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 193, 1, 32, 2, 1,
> >> + { 154000000, 193, 193, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 193, 1, 32, 2, 1,
> >> 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 1485000, 0x7b, 0x7b, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 4, 0, 3, 5, 5,
> >> + { 148500000, 0x7b, 0x7b, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 4, 0, 3, 5, 5,
> >> 0x10, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 1462500, 122, 122, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 244, 1, 16, 2, 1, 1,
> >> + { 146250000, 122, 122, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 244, 1, 16, 2, 1, 1,
> >> 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 1190000, 149, 149, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 149, 1, 16, 2, 1, 1,
> >> + { 119000000, 149, 149, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 149, 1, 16, 2, 1, 1,
> >> 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 1065000, 89, 89, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 89, 1, 16, 1, 0, 1,
> >> + { 106500000, 89, 89, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 89, 1, 16, 1, 0, 1,
> >> 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 1080000, 135, 135, 1, 1, 5, 1, 1, 0, 1, 0, 1, 1, 0x9, 0, 0x05, 0,
> >> + { 108000000, 135, 135, 1, 1, 5, 1, 1, 0, 1, 0, 1, 1, 0x9, 0, 0x05, 0,
> >> 0x14, 0x18, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 855000, 214, 214, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 214, 1, 16, 2, 1,
> >> + { 85500000, 214, 214, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 214, 1, 16, 2, 1,
> >> 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 835000, 105, 105, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 42, 1, 16, 1, 0,
> >> + { 83500000, 105, 105, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 42, 1, 16, 1, 0,
> >> 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 928125, 155, 155, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> + { 92812500, 155, 155, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 742500, 124, 124, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> + { 74250000, 124, 124, 1, 1, 7, 1, 1, 1, 1, 1, 1, 1, 62, 1, 16, 5, 0,
> >> 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 650000, 162, 162, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 54, 0, 16, 4, 1,
> >> + { 65000000, 162, 162, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 54, 0, 16, 4, 1,
> >> 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 337500, 0x70, 0x70, 1, 1, 0xf, 1, 1, 1, 1, 1, 1, 1, 0x2, 0, 0x01, 5,
> >> + { 33750000, 0x70, 0x70, 1, 1, 0xf, 1, 1, 1, 1, 1, 1, 1, 0x2, 0, 0x01, 5,
> >> 1, 1, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 400000, 100, 100, 1, 1, 11, 1, 1, 0, 1, 0, 1, 1, 0x9, 0, 0x05, 0,
> >> + { 40000000, 100, 100, 1, 1, 11, 1, 1, 0, 1, 0, 1, 1, 0x9, 0, 0x05, 0,
> >> 0x14, 0x18, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 270000, 0x5a, 0x5a, 1, 1, 0xf, 1, 1, 0, 1, 0, 1, 1, 0x9, 0, 0x05, 0,
> >> + { 27000000, 0x5a, 0x5a, 1, 1, 0xf, 1, 1, 0, 1, 0, 1, 1, 0x9, 0, 0x05, 0,
> >> 0x14, 0x18, 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> - { 251750, 84, 84, 1, 1, 0xf, 1, 1, 1, 1, 1, 1, 1, 168, 1, 16, 4, 1, 1,
> >> + { 25175000, 84, 84, 1, 1, 0xf, 1, 1, 1, 1, 1, 1, 1, 168, 1, 16, 4, 1, 1,
> >> 1, 0, 0x20, 0x0c, 1, 0x0e, 0, 0, },
> >> };
> >>
> >> @@ -894,10 +894,10 @@ static void rk_hdptx_phy_disable(struct rk_hdptx_phy *hdptx)
> >> regmap_write(hdptx->grf, GRF_HDPTX_CON0, val);
> >> }
> >>
> >> -static bool rk_hdptx_phy_clk_pll_calc(unsigned int data_rate,
> >> +static bool rk_hdptx_phy_clk_pll_calc(unsigned long rate,
> >
> > here and further, unsigned long long
> > Also, is it tmds_char_rate?
>
> Yes, will do the suggested changes in v6.
>
> Thanks,
> Cristian
>