linux-kernel - [PATCH 1/2] drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver

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Date:   Fri, 16 Apr 2021 11:27:36 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     jonas@...boo.se, jernej.skrabec@...l.net, robert.foss@...aro.org,
        Laurent.pinchart@...asonboard.com
Cc:     dri-devel@...ts.freedesktop.org, linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Neil Armstrong <narmstrong@...libre.com>
Subject: [PATCH 1/2] drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver

From: Jernej Skrabec <jernej.skrabec@...l.net>

This adds DW-HDMI driver a glue option to disable loading of the CEC sub-driver.

On some SoCs, the CEC functionality is enabled in the IP config bits, but the
CEC bus is non-functional like on Amlogic SoCs, where the CEC config bit is set
but the DW-HDMI CEC signal is not connected to a physical pin, leading to some
confusion when the DW-HDMI CEC controller can't communicate on the bus.

Reviewed-by: Neil Armstrong <narmstrong@...libre.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@...l.net>
Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 2 +-
 include/drm/bridge/dw_hdmi.h              | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index dda4fa9a1a08..ae97513ef886 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -3421,7 +3421,7 @@ struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
 		hdmi->audio = platform_device_register_full(&pdevinfo);
 	}
 
-	if (config0 & HDMI_CONFIG0_CEC) {
+	if (!plat_data->disable_cec && (config0 & HDMI_CONFIG0_CEC)) {
 		cec.hdmi = hdmi;
 		cec.ops = &dw_hdmi_cec_ops;
 		cec.irq = irq;
diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
index ea34ca146b82..6a5716655619 100644
--- a/include/drm/bridge/dw_hdmi.h
+++ b/include/drm/bridge/dw_hdmi.h
@@ -153,6 +153,8 @@ struct dw_hdmi_plat_data {
 	const struct dw_hdmi_phy_config *phy_config;
 	int (*configure_phy)(struct dw_hdmi *hdmi, void *data,
 			     unsigned long mpixelclock);
+
+	unsigned int disable_cec : 1;
 };
 
 struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
-- 
2.25.1