drm: mediatek: mtk_dsi: Fix NO_EOT_PACKET settings/handling

[ Upstream commit 5855d422a6f250f3518f43b49092c8e87a5e42be ]

Due to the initial confusion about MIPI_DSI_MODE_EOT_PACKET, properly
renamed to MIPI_DSI_MODE_NO_EOT_PACKET, reflecting its actual meaning,
both the DSI_TXRX_CON register setting for bit (HSTX_)DIS_EOT and the
later calculation for horizontal sync-active (HSA), back (HBP) and
front (HFP) porches got incorrect due to the logic being inverted.

This means that a number of settings were wrong because....:
 - DSI_TXRX_CON register setting: bit (HSTX_)DIS_EOT should be
   set in order to disable the End of Transmission packet;
 - Horizontal Sync and Back/Front porches: The delta used to
   calculate all of HSA, HBP and HFP should account for the
   additional EOT packet.

Before this change...
 - Bit (HSTX_)DIS_EOT was being set when EOT packet was enabled;
 - For HSA/HBP/HFP delta... all three were wrong, as words were
   added when EOT disabled, instead of when EOT packet enabled!

Invert the logic around flag MIPI_DSI_MODE_NO_EOT_PACKET in the
MediaTek DSI driver to fix the aforementioned issues.

Fixes: 8b2b99fd7931 ("drm/mediatek: dsi: Fine tune the line time caused by EOTp")
Fixes: c87d1c4b5b9a ("drm/mediatek: dsi: Use symbolized register definition")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Alexandre Mergnat <amergnat@baylibre.com>
Tested-by: Michael Walle <mwalle@kernel.org>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20230523104234.7849-1-angelogioacchino.delregno@collabora.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 9e1363c..3e74c7c 100644 (file)
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -406,7 +406,7 @@ static void mtk_dsi_rxtx_control(struct mtk_dsi *dsi)
        if (dsi->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS)
                tmp_reg |= HSTX_CKLP_EN;
 
-       if (!(dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET))
+       if (dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET)
                tmp_reg |= DIS_EOT;
 
        writel(tmp_reg, dsi->regs + DSI_TXRX_CTRL);
@@ -483,7 +483,7 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
                          timing->da_hs_zero + timing->da_hs_exit + 3;
 
        delta = dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST ? 18 : 12;
-       delta += dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET ? 2 : 0;
+       delta += dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET ? 0 : 2;
 
        horizontal_frontporch_byte = vm->hfront_porch * dsi_tmp_buf_bpp;
        horizontal_front_back_byte = horizontal_frontporch_byte + horizontal_backporch_byte;