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Tue, 12 Apr 2022 06:08:47 -0700 Received: from mtkexhb02.mediatek.inc (172.21.101.103) by MTKMBS62N1.mediatek.inc (172.29.193.41) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 12 Apr 2022 06:08:46 -0700 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkexhb02.mediatek.inc (172.21.101.103) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 12 Apr 2022 21:08:44 +0800 Received: from mszsdhlt06 (10.16.6.206) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Tue, 12 Apr 2022 21:08:43 +0800 Message-ID: <340df66f9f541cc90cd954bd6c555d2bcb384e9a.camel@mediatek.com> Subject: Re: [PATCH v4, 3/4] drm/mediatek: keep dsi as LP00 before dcs cmds transfer From: xinlei.lee To: Rex-BC Chen , AngeloGioacchino Del Regno , , , , , CC: , , , , , Date: Tue, 12 Apr 2022 21:09:14 +0800 In-Reply-To: <3c9140fbba123550b5532f9917dae4ef10ed5611.camel@mediatek.com> References: <1649644308-8455-1-git-send-email-xinlei.lee@mediatek.com> <1649644308-8455-4-git-send-email-xinlei.lee@mediatek.com> <7a4e5afb-6947-ed7f-8555-c7402aaa3a29@collabora.com> <3c9140fbba123550b5532f9917dae4ef10ed5611.camel@mediatek.com> X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220412_060853_950346_654A0ED2 X-CRM114-Status: GOOD ( 26.54 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 2022-04-12 at 15:43 +0800, Rex-BC Chen wrote: > On Mon, 2022-04-11 at 11:07 +0200, AngeloGioacchino Del Regno wrote: > > Il 11/04/22 04:31, xinlei.lee@mediatek.com ha scritto: > > > From: Jitao Shi > > > > > > To comply with the panel sequence, hold the mipi signal to LP00 > > > before the dcs cmds transmission, > > > and pull the mipi signal high from LP00 to LP11 until the start > > > of > > > the dcs cmds transmission. > > > The normal panel timing is : > > > (1) pp1800 DC pull up > > > (2) avdd & avee AC pull high > > > (3) lcm_reset pull high -> pull low -> pull high > > > (4) Pull MIPI signal high (LP11) -> initial code -> send video > > > data(HS mode) > > > The power-off sequence is reversed. > > > If dsi is not in cmd mode, then dsi will pull the mipi signal > > > high > > > in the mtk_output_dsi_enable function. > > > > > > Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the > > > drm_panel_bridge API") > > > > > > Signed-off-by: Jitao Shi > > > Signed-off-by: Xinlei Lee > > > --- > > > drivers/gpu/drm/mediatek/mtk_dsi.c | 28 +++++++++++++++++++++-- > > > ----- > > > 1 file changed, 21 insertions(+), 7 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c > > > b/drivers/gpu/drm/mediatek/mtk_dsi.c > > > index cf76c53a1af6..9ad6f08c8bfe 100644 > > > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c > > > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c > > > @@ -203,6 +203,7 @@ struct mtk_dsi { > > > struct mtk_phy_timing phy_timing; > > > int refcount; > > > bool enabled; > > > + bool lanes_ready; > > > u32 irq_data; > > > wait_queue_head_t irq_wait_queue; > > > const struct mtk_dsi_driver_data *driver_data; > > > @@ -654,13 +655,6 @@ static int mtk_dsi_poweron(struct mtk_dsi > > > *dsi) > > > mtk_dsi_config_vdo_timing(dsi); > > > mtk_dsi_set_interrupt_enable(dsi); > > > > > > - mtk_dsi_rxtx_control(dsi); > > > - usleep_range(30, 100); > > > - mtk_dsi_reset_dphy(dsi); > > > - mtk_dsi_clk_ulp_mode_leave(dsi); > > > - mtk_dsi_lane0_ulp_mode_leave(dsi); > > > - mtk_dsi_clk_hs_mode(dsi, 0); > > > - > > > return 0; > > > err_disable_engine_clk: > > > clk_disable_unprepare(dsi->engine_clk); > > > @@ -689,6 +683,23 @@ static void mtk_dsi_poweroff(struct mtk_dsi > > > *dsi) > > > clk_disable_unprepare(dsi->digital_clk); > > > > > > phy_power_off(dsi->phy); > > > + > > > + dsi->lanes_ready = false; > > > +} > > > + > > > +static void mtk_dsi_lane_ready(struct mtk_dsi *dsi) > > > +{ > > > + if (!dsi->lanes_ready) { > > > + dsi->lanes_ready = true; > > > + mtk_dsi_rxtx_control(dsi); > > > + usleep_range(30, 100); > > > + mtk_dsi_reset_dphy(dsi); > > > + mtk_dsi_clk_ulp_mode_leave(dsi); > > > + mtk_dsi_lane0_ulp_mode_leave(dsi); > > > + mtk_dsi_clk_hs_mode(dsi, 0); > > > + msleep(20); > > > > This is a very long sleep, which wasn't present before this change. > > Please document the reasons why we need this 20ms sleep with a > > comment > > in the code. > > > > Regards, > > Angelo > > > > > > Hello Xinlei, > > As Angelo mentioned. > I think you should add this in commit message and driver comments. > (Your reply in v3.) > "The 20ms delay in mtk_dsi_lane_ready() is because dsi needs to give > dsi_rx(panel) a reaction time after pulling up the mipi signal." > > BRs, > Rex > Hey Rex: Thanks for your review and reminder. I will add this explanation in the next edition of code & comments. Best Regards! xinlei _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel