From patchwork Mon Jul 17 06:18:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Liu Ying X-Patchwork-Id: 13316392 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail-vi1eur05on20614.outbound.protection.outlook.com ([2a01:111:f400:7d00::614] helo=EUR05-VI1-obe.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qLHV2-002zno-1Y for linux-arm-kernel@lists.infradead.org; Mon, 17 Jul 2023 06:14:26 +0000 From: Liu Ying Subject: [PATCH 6/9] drm/bridge: synopsys: dw-mipi-dsi: Set minimum lane byte clock cycles for HSA and HBP Date: Mon, 17 Jul 2023 14:18:28 +0800 Message-Id: <20230717061831.1826878-7-victor.liu@nxp.com> In-Reply-To: <20230717061831.1826878-1-victor.liu@nxp.com> References: <20230717061831.1826878-1-victor.liu@nxp.com> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+lwn-linux-arm-kernel=archive.lwn.net@lists.infradead.org List-Archive: To: dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: andrzej.hajda@intel.com, neil.armstrong@linaro.org, rfoss@kernel.org, Laurent.pinchart@ideasonboard.com, jonas@kwiboo.se, jernej.skrabec@gmail.com, airlied@gmail.com, daniel@ffwll.ch, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com According to Synopsys support channel, each region of HSA, HBP and HFP must have minimum number of 10 bytes where constant 4 bytes are for HSS or HSE and 6 bytes are for blanking packet(header + CRC). Hence, the below table comes in. +------------+----------+-------+ | data lanes | min lbcc | bytes | +------------+----------+-------+ | 1 | 10 | 1*10 | +------------+----------+-------+ | 2 | 5 | 2*5 | +------------+----------+-------+ | 3 | 4 | 3*4 | +------------+----------+-------+ | 4 | 3 | 4*3 | +------------+----------+-------+ Implement the minimum lbcc numbers to make sure that the values programmed into DSI_VID_HSA_TIME and DSI_VID_HBP_TIME registers meet the minimum number requirement. For DSI_VID_HLINE_TIME register, it seems that the value programmed should be based on mode->htotal as-is, instead of sum up HSA, HBP, HFP and HDISPLAY. This helps the case where Raydium RM67191 DSI panel is connected, since it's video timing for hsync length is only 2 pixels and without this patch the programmed value for DSI_VID_HSA_TIME is only 2 with 4 data lanes. Signed-off-by: Liu Ying Reviewed-by: Neil Armstrong --- drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c index 332388fd86da..536306ccea5a 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c @@ -757,12 +757,19 @@ static void dw_mipi_dsi_command_mode_config(struct dw_mipi_dsi *dsi) dsi_write(dsi, DSI_MODE_CFG, ENABLE_CMD_MODE); } +static const u32 minimum_lbccs[] = {10, 5, 4, 3}; + +static inline u32 dw_mipi_dsi_get_minimum_lbcc(struct dw_mipi_dsi *dsi) +{ + return minimum_lbccs[dsi->lanes - 1]; +} + /* Get lane byte clock cycles. */ static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi, const struct drm_display_mode *mode, u32 hcomponent) { - u32 frac, lbcc; + u32 frac, lbcc, minimum_lbcc; int bpp; bpp = mipi_dsi_pixel_format_to_bpp(dsi->format); @@ -778,6 +785,11 @@ static u32 dw_mipi_dsi_get_hcomponent_lbcc(struct dw_mipi_dsi *dsi, if (frac) lbcc++; + minimum_lbcc = dw_mipi_dsi_get_minimum_lbcc(dsi); + + if (lbcc < minimum_lbcc) + lbcc = minimum_lbcc; + return lbcc; }