[PATCH v9 31/61] drm/rockchip: dw_hdmi_qp: Control the HPD IRQ line via the bridge HPD ops

[Cristian Ciocaltea]

The HPD interrupt must not be delivered before the DRM connector is fully
set up, and it should be quiesced while the display pipeline is suspended.
On top of that, the threaded handler re-arms HPD unconditionally after the
hotplug debounce, which must not override an explicit disable requested by
the DRM core.

Request the HPD IRQ in bind() with IRQF_NO_AUTOEN so it stays disabled
until the core arms it, and drive enable_irq()/disable_irq() from the
phy ops invoked by the bridge through its hpd_{enable,disable}()
callbacks.  This ensures the line is only armed after the connector is
ready.  disable_irq() additionally waits for the threaded handler to
finish, so its GRF re-arm can no longer race with and override a
core-requested disable.

Note that IRQF_NO_AUTOEN is incompatible with IRQF_SHARED; the latter is
dropped as this IRQ has no other users.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea at collabora.com>
---
 drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
index cdddbbb8b80b..534a2c8da2a0 100644
--- a/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_hdmi_qp-rockchip.c
@@ -99,6 +99,7 @@ struct rockchip_hdmi_qp {
 	struct phy *phy;
 	struct gpio_desc *frl_enable_gpio;
 	struct delayed_work hpd_work;
+	int hpd_irq;
 	int port_id;
 	const struct rockchip_hdmi_qp_ctrl_ops *ctrl_ops;
 	unsigned long long tmds_char_rate;
@@ -308,12 +309,14 @@ static void dw_hdmi_qp_rk3588_enable_hpd(struct dw_hdmi_qp *dw_hdmi, void *data)
 	struct rockchip_hdmi_qp *hdmi = (struct rockchip_hdmi_qp *)data;
 
 	dw_hdmi_qp_rk3588_unmask_hpd(hdmi);
+	enable_irq(hdmi->hpd_irq);
 }
 
 static void dw_hdmi_qp_rk3588_disable_hpd(struct dw_hdmi_qp *dw_hdmi, void *data)
 {
 	struct rockchip_hdmi_qp *hdmi = (struct rockchip_hdmi_qp *)data;
 
+	disable_irq(hdmi->hpd_irq);
 	dw_hdmi_qp_rk3588_mask_hpd(hdmi);
 }
 
@@ -355,12 +358,14 @@ static void dw_hdmi_qp_rk3576_enable_hpd(struct dw_hdmi_qp *dw_hdmi, void *data)
 	struct rockchip_hdmi_qp *hdmi = (struct rockchip_hdmi_qp *)data;
 
 	dw_hdmi_qp_rk3576_unmask_hpd(hdmi);
+	enable_irq(hdmi->hpd_irq);
 }
 
 static void dw_hdmi_qp_rk3576_disable_hpd(struct dw_hdmi_qp *dw_hdmi, void *data)
 {
 	struct rockchip_hdmi_qp *hdmi = (struct rockchip_hdmi_qp *)data;
 
+	disable_irq(hdmi->hpd_irq);
 	dw_hdmi_qp_rk3576_mask_hpd(hdmi);
 }
 
@@ -584,7 +589,7 @@ static int dw_hdmi_qp_rockchip_bind(struct device *dev, struct device *master,
 	struct resource *res;
 	struct clk_bulk_data *clks;
 	struct clk *ref_clk;
-	int ret, irq, i;
+	int ret, i;
 
 	if (!dev->of_node)
 		return -ENODEV;
@@ -688,14 +693,14 @@ static int dw_hdmi_qp_rockchip_bind(struct device *dev, struct device *master,
 	if (plat_data.cec_irq < 0)
 		return plat_data.cec_irq;
 
-	irq = platform_get_irq_byname(pdev, "hpd");
-	if (irq < 0)
-		return irq;
+	hdmi->hpd_irq = platform_get_irq_byname(pdev, "hpd");
+	if (hdmi->hpd_irq < 0)
+		return hdmi->hpd_irq;
 
-	ret = devm_request_threaded_irq(dev, irq,
+	ret = devm_request_threaded_irq(dev, hdmi->hpd_irq,
 					cfg->ctrl_ops->hardirq_callback,
 					cfg->ctrl_ops->irq_callback,
-					IRQF_SHARED, "dw-hdmi-qp-hpd",
+					IRQF_NO_AUTOEN, "dw-hdmi-qp-hpd",
 					hdmi);
 	if (ret)
 		return ret;

-- 
2.55.0