linux-kernel - [PATCH v2 1/2] drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver

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Date:   Mon,  1 Apr 2019 21:15:12 +0200
From:   Jernej Skrabec <jernej.skrabec@...l.net>
To:     maxime.ripard@...tlin.com
Cc:     a.hajda@...sung.com, Laurent.pinchart@...asonboard.com,
        airlied@...ux.ie, daniel@...ll.ch, wens@...e.org,
        narmstrong@...libre.com, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: [PATCH v2 1/2] drm/bridge/synopsys: dw-hdmi: Add an option to suppress loading CEC driver

DW HDMI controller on some Allwinner SoCs has support for CEC, but due
to additional logic put between CEC controller and pins, it doesn't work
correctly, at least not with a lot of instrusive changes. Fortunately,
it's still possible to bitbang protocol.

For such cases, add a platform option to suppress loading CEC driver. If
DW HDMI CEC driver would be loaded, it wouldn't work anyway and would only
cause a confusion with multiple /dev entries.

Reviewed-by: Neil Armstrong <narmstrong@...libre.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@...l.net>
---
 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 db761329a1e3..d2b0aa8d964c 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -2660,7 +2660,7 @@ __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 66e70770cce5..c03bea3a1a36 100644
--- a/include/drm/bridge/dw_hdmi.h
+++ b/include/drm/bridge/dw_hdmi.h
@@ -144,6 +144,8 @@ struct dw_hdmi_plat_data {
 	int (*configure_phy)(struct dw_hdmi *hdmi,
 			     const struct dw_hdmi_plat_data *pdata,
 			     unsigned long mpixelclock);
+
+	unsigned int disable_cec : 1;
 };
 
 struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
-- 
2.21.0