From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Jagan Teki <jagan@amarulasolutions.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
devicetree <devicetree@vger.kernel.org>,
David Airlie <airlied@linux.ie>,
Michael Turquette <mturquette@baylibre.com>,
linux-sunxi <linux-sunxi@googlegroups.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Chen-Yu Tsai <wens@csie.org>, Rob Herring <robh+dt@kernel.org>,
Daniel Vetter <daniel@ffwll.ch>,
Michael Trimarchi <michael@amarulasolutions.com>,
linux-amarula@amarulasolutions.com,
linux-clk <linux-clk@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v6 11/22] clk: sunxi-ng: a64: Add minimum rate for PLL_MIPI
Date: Tue, 29 Jan 2019 16:13:48 +0100 [thread overview]
Message-ID: <20190129151348.mh27btttsqcmeban@flea> (raw)
In-Reply-To: <CAMty3ZAsH2iZ+JEqTE3D58aXfGuhMSg9YoO56ZhhOeE4c4yQHQ@mail.gmail.com>
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On Mon, Jan 28, 2019 at 03:06:10PM +0530, Jagan Teki wrote:
> On Sat, Jan 26, 2019 at 2:54 AM Maxime Ripard <maxime.ripard@bootlin.com> wrote:
> >
> > On Fri, Jan 25, 2019 at 01:28:49AM +0530, Jagan Teki wrote:
> > > Minimum PLL used for MIPI is 500MHz, as per manual, but
> > > lowering the min rate by 300MHz can result proper working
> > > nkms divider with the help of desired dclock rate from
> > > panel driver.
> > >
> > > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> > > Acked-by: Stephen Boyd <sboyd@kernel.org>
> >
> > Going 200MHz below the minimum doesn't seem really reasonable. What
> > is the issue that you are trying to fix here?
> >
> > It looks like it's picking bad dividers, but if that's the case, this
> > isn't the proper fix.
>
> As I stated in earlier patches, the whole idea is pick the desired
> dclk divider based dclk rate. So the dotclock, sun4i_dclk_round_rate
> is unable to get the proper dclk divider at the end, so it eventually
> picking up wrong divider value and fired vblank timeout.
>
> So, we come-up with optimal and working min_rate 300MHz in pll-mipi to
> get the desired clock something like below.
> [ 2.415773] [drm] No driver support for vblank timestamp query.
> [ 2.424116] sun4i_dclk_round_rate: min_div = 4 max_div = 127, rate = 55000000
> [ 2.424172] ideal = 220000000, rounded = 0
> [ 2.424176] ideal = 275000000, rounded = 0
> [ 2.424194] ccu_nkm_round_rate: rate = 330000000
> [ 2.424197] ideal = 330000000, rounded = 330000000
> [ 2.424201] sun4i_dclk_round_rate: div = 6 rate = 55000000
> [ 2.424205] sun4i_dclk_round_rate: min_div = 4 max_div = 127, rate = 55000000
> [ 2.424209] ideal = 220000000, rounded = 0
> [ 2.424213] ideal = 275000000, rounded = 0
> [ 2.424230] ccu_nkm_round_rate: rate = 330000000
> [ 2.424233] ideal = 330000000, rounded = 330000000
> [ 2.424236] sun4i_dclk_round_rate: div = 6 rate = 55000000
> [ 2.424253] ccu_nkm_round_rate: rate = 330000000
> [ 2.424270] ccu_nkm_round_rate: rate = 330000000
> [ 2.424278] sun4i_dclk_recalc_rate: val = 1, rate = 330000000
> [ 2.424281] sun4i_dclk_recalc_rate: val = 1, rate = 330000000
> [ 2.424306] ccu_nkm_set_rate: rate = 330000000, parent_rate = 297000000
> [ 2.424309] ccu_nkm_set_rate: _nkm.n = 5
> [ 2.424311] ccu_nkm_set_rate: _nkm.k = 2
> [ 2.424313] ccu_nkm_set_rate: _nkm.m = 9
> [ 2.424661] sun4i_dclk_set_rate div 6
> [ 2.424668] sun4i_dclk_recalc_rate: val = 6, rate = 55000000
>
> But look like this wouldn't valid for all other dclock rates, say BPI
> panel has 30MHz clock that would failed with this logic.
>
> On the other side Allwinner BSP calculating dclk divider based on the
> SoC's. for A33 [1] it is fixed dclk divider of 4 and for A64 is is
> calculated based on the bpp/lanes.
It looks like the A64 has the same divider of 4:
https://github.com/BPI-SINOVOIP/BPI-M64-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c#L12
I think you're confusing it with the ratio between the pixel clock and
the dotclock, called dsi_div:
https://github.com/BPI-SINOVOIP/BPI-M64-bsp/blob/master/linux-sunxi/drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/disp_al.c#L198
Maxime
--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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next prev parent reply other threads:[~2019-01-29 15:14 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-24 19:58 [PATCH v6 00/22] drm/sun4i: Allwinner A64 MIPI-DSI support Jagan Teki
2019-01-24 19:58 ` [PATCH v6 01/22] drm/sun4i: sun6i_mipi_dsi: Compute burst mode loop N1 instruction delay Jagan Teki
2019-01-24 19:58 ` [PATCH v6 02/22] drm/sun4i: sun6i_mipi_dsi: Support instruction loop selection Jagan Teki
2019-01-24 19:58 ` [PATCH v6 03/22] drm/sun4i: sun6i_mipi_dsi: Setup burst mode timings Jagan Teki
2019-01-24 19:58 ` [PATCH v6 04/22] drm/sun4i: sun6i_mipi_dsi: Simplify drq to support all modes Jagan Teki
2019-01-24 19:58 ` [PATCH v6 05/22] drm/sun4i: tcon: Export get tcon0 routine Jagan Teki
2019-01-24 19:58 ` [PATCH v6 06/22] drm/sun4i: sun6i_mipi_dsi: Probe tcon0 during dsi_bind Jagan Teki
2019-01-24 19:58 ` [PATCH v6 07/22] drm/sun4i: sun6i_mipi_dsi: Setup burst mode Jagan Teki
2019-01-24 19:58 ` [PATCH v6 08/22] drm/sun4i: sun6i_mipi_dsi: Enable 2byte trail for 4-lane " Jagan Teki
2019-01-24 19:58 ` [PATCH v6 09/22] drm/sun4i: sun6i_mipi_dsi: Enable burst mode HBP, HSA_HSE Jagan Teki
2019-01-24 19:58 ` [PATCH v6 10/22] clk: sunxi-ng: Add check for minimal rate to NKM PLLs Jagan Teki
2019-01-24 19:58 ` [PATCH v6 11/22] clk: sunxi-ng: a64: Add minimum rate for PLL_MIPI Jagan Teki
2019-01-25 21:24 ` Maxime Ripard
2019-01-28 9:36 ` Jagan Teki
2019-01-29 15:13 ` Maxime Ripard [this message]
2019-01-29 17:31 ` Jagan Teki
2019-02-01 14:31 ` Maxime Ripard
2019-02-01 16:33 ` Jagan Teki
2019-02-11 14:07 ` Jagan Teki
2019-02-12 9:30 ` Maxime Ripard
2019-02-12 9:38 ` Jagan Teki
2019-05-24 10:07 ` Jagan Teki
2019-06-05 6:49 ` Maxime Ripard
2019-06-05 7:33 ` Jagan Teki
2019-06-14 14:24 ` Maxime Ripard
2019-06-20 18:27 ` Jagan Teki
2019-06-25 14:49 ` Maxime Ripard
2019-06-25 15:30 ` Jagan Teki
2019-07-03 11:49 ` Maxime Ripard
2019-07-05 17:52 ` Michael Nazzareno Trimarchi
2019-07-11 10:01 ` Maxime Ripard
2019-07-11 17:43 ` Michael Nazzareno Trimarchi
2019-07-11 19:34 ` Michael Nazzareno Trimarchi
2019-07-20 6:58 ` Maxime Ripard
2019-07-20 7:16 ` Jagan Teki
2019-07-20 7:34 ` Jagan Teki
2019-07-20 9:32 ` Maxime Ripard
2019-07-20 9:42 ` Michael Nazzareno Trimarchi
2019-07-22 10:21 ` Jagan Teki
2019-07-22 10:25 ` Michael Nazzareno Trimarchi
2019-07-22 10:38 ` Jagan Teki
2019-07-24 9:05 ` Maxime Ripard
2019-07-29 6:59 ` Michael Nazzareno Trimarchi
2019-08-02 8:38 ` Michael Nazzareno Trimarchi
2019-08-13 6:05 ` Maxime Ripard
2019-08-15 12:25 ` Michael Nazzareno Trimarchi
2019-08-28 13:03 ` Maxime Ripard
2019-08-28 13:09 ` Michael Nazzareno Trimarchi
2019-01-24 19:58 ` [PATCH v6 12/22] dt-bindings: sun6i-dsi: Add VCC-DSI supply property Jagan Teki
2019-01-25 15:47 ` Maxime Ripard
2019-01-24 19:58 ` [PATCH v6 13/22] drm/sun4i: sun6i_mipi_dsi: Add support for VCC-DSI voltage regulator Jagan Teki
2019-01-24 19:58 ` [PATCH v6 14/22] dt-bindings: sun6i-dsi: Add A64 DSI compatible (w/ A31 fallback) Jagan Teki
2019-01-25 15:52 ` Maxime Ripard
2019-01-26 16:09 ` [linux-sunxi] " Jagan Teki
2019-01-29 14:54 ` Maxime Ripard
2019-01-24 19:58 ` [PATCH v6 15/22] dt-bindings: sun6i-dsi: Add A64 DPHY " Jagan Teki
2019-01-25 15:52 ` Maxime Ripard
2019-01-24 19:58 ` [PATCH v6 16/22] arm64: dts: allwinner: a64: Add DSI pipeline Jagan Teki
2019-01-25 18:51 ` Maxime Ripard
2019-01-24 19:58 ` [DO NOT MERGE] [PATCH v6 17/22] arm64: allwinner: a64: pine64-lts: Enable Feiyang FY07024DI26A30-D DSI panel Jagan Teki
2019-01-24 19:58 ` [PATCH v6 18/22] drm/sun4i: sun6i_mipi_dsi: Add DSI Generic short write 2 param transfer Jagan Teki
2019-01-24 19:58 ` [DO NOT MERGE] [PATCH v6 19/22] arm64: dts: allwinner: bananapi-m64: Bananapi S070WV20-CT16 DSI panel Jagan Teki
2019-01-24 19:58 ` [PATCH v6 20/22] drm/sun4i: sun6i_mipi_dsi: Fix DSI hbp timing value Jagan Teki
2019-01-24 19:58 ` [PATCH v6 21/22] drm/sun4i: sun6i_mipi_dsi: Fix DSI hfp " Jagan Teki
2019-01-24 19:59 ` [PATCH v6 22/22] arm64: dts: allwinner: a64-amarula-relic: Add Techstar TS8550B MIPI-DSI panel Jagan Teki
2019-01-24 23:12 ` [PATCH v6 00/22] drm/sun4i: Allwinner A64 MIPI-DSI support Merlijn Wajer
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