linux-kernel - [PATCH] drm/bridge/synopsys: dsi: add optional pixel clock

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Date:   Thu, 26 Oct 2017 18:09:35 +0200
From:   Philippe Cornu <philippe.cornu@...com>
To:     Archit Taneja <architt@...eaurora.org>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        David Airlie <airlied@...ux.ie>,
        Philippe Cornu <philippe.cornu@...com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Benjamin Gaignard <benjamin.gaignard@...aro.org>,
        Bhumika Goyal <bhumirks@...il.com>,
        <dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
CC:     Yannick Fertre <yannick.fertre@...com>,
        Vincent Abriou <vincent.abriou@...com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        "Maxime Coquelin" <mcoquelin.stm32@...il.com>,
        Gabriel Fernandez <gabriel.fernandez@...com>,
        Ludovic Barre <ludovic.barre@...com>,
        "Fabien Dessenne" <fabien.dessenne@...com>,
        Mickael Reulier <mickael.reulier@...com>
Subject: [PATCH] drm/bridge/synopsys: dsi: add optional pixel clock

The pixel clock is optional. When available, it offers a better
preciseness for timing computations.

Signed-off-by: Philippe Cornu <philippe.cornu@...com>
---
 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index d9cca4f..8b3787d 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -225,6 +225,7 @@ struct dw_mipi_dsi {
 	void __iomem *base;
 
 	struct clk *pclk;
+	struct clk *px_clk;
 
 	unsigned int lane_mbps; /* per lane */
 	u32 channel;
@@ -753,24 +754,28 @@ void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,
 	struct dw_mipi_dsi *dsi = bridge_to_dsi(bridge);
 	const struct dw_mipi_dsi_phy_ops *phy_ops = dsi->plat_data->phy_ops;
 	void *priv_data = dsi->plat_data->priv_data;
+	struct drm_display_mode px_clk_mode = *mode;
 	int ret;
 
 	clk_prepare_enable(dsi->pclk);
 
-	ret = phy_ops->get_lane_mbps(priv_data, mode, dsi->mode_flags,
+	if (dsi->px_clk)
+		px_clk_mode.clock = clk_get_rate(dsi->px_clk) / 1000;
+
+	ret = phy_ops->get_lane_mbps(priv_data, &px_clk_mode, dsi->mode_flags,
 				     dsi->lanes, dsi->format, &dsi->lane_mbps);
 	if (ret)
 		DRM_DEBUG_DRIVER("Phy get_lane_mbps() failed\n");
 
 	pm_runtime_get_sync(dsi->dev);
 	dw_mipi_dsi_init(dsi);
-	dw_mipi_dsi_dpi_config(dsi, mode);
+	dw_mipi_dsi_dpi_config(dsi, &px_clk_mode);
 	dw_mipi_dsi_packet_handler_config(dsi);
 	dw_mipi_dsi_video_mode_config(dsi);
-	dw_mipi_dsi_video_packet_config(dsi, mode);
+	dw_mipi_dsi_video_packet_config(dsi, &px_clk_mode);
 	dw_mipi_dsi_command_mode_config(dsi);
-	dw_mipi_dsi_line_timer_config(dsi, mode);
-	dw_mipi_dsi_vertical_timing_config(dsi, mode);
+	dw_mipi_dsi_line_timer_config(dsi, &px_clk_mode);
+	dw_mipi_dsi_vertical_timing_config(dsi, &px_clk_mode);
 
 	dw_mipi_dsi_dphy_init(dsi);
 	dw_mipi_dsi_dphy_timing_config(dsi);
@@ -784,7 +789,7 @@ void dw_mipi_dsi_bridge_mode_set(struct drm_bridge *bridge,
 
 	dw_mipi_dsi_dphy_enable(dsi);
 
-	dw_mipi_dsi_wait_for_two_frames(mode);
+	dw_mipi_dsi_wait_for_two_frames(&px_clk_mode);
 
 	/* Switch to cmd mode for panel-bridge pre_enable & panel prepare */
 	dw_mipi_dsi_set_mode(dsi, 0);
@@ -878,6 +883,13 @@ static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge)
 		return ERR_PTR(ret);
 	}
 
+	dsi->px_clk = devm_clk_get(dev, "px_clk");
+	if (IS_ERR(dsi->px_clk)) {
+		ret = PTR_ERR(dsi->px_clk);
+		dev_dbg(dev, "Unable to get optional px_clk: %d\n", ret);
+		dsi->px_clk = NULL;
+	}
+
 	/*
 	 * Note that the reset was not defined in the initial device tree, so
 	 * we have to be prepared for it not being found.
-- 
1.9.1