[PATCH v6 05/14] drm/exynos: dsi: add TE interrupt handler to support LCD I80 interface

[YoungJun Cho]

To support LCD I80 interface, the DSI host should register
TE interrupt handler from the TE GPIO of attached panel.
So the panel generates a tearing effect synchronization signal
then the DSI host calls the CRTC device manager to trigger
to transfer video image.

Signed-off-by: YoungJun Cho <yj44.cho at samsung.com>
Acked-by: Inki Dae <inki.dae at samsung.com>
Acked-by: Kyungmin Park <kyungmin.park at samsung.com>
---
 drivers/gpu/drm/exynos/exynos_drm_dsi.c | 95 ++++++++++++++++++++++++++++++++-
 1 file changed, 93 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index 58bfb2a..4997bfe 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -16,7 +16,9 @@
 #include <drm/drm_panel.h>
 
 #include <linux/clk.h>
+#include <linux/gpio/consumer.h>
 #include <linux/irq.h>
+#include <linux/of_gpio.h>
 #include <linux/phy/phy.h>
 #include <linux/regulator/consumer.h>
 #include <linux/component.h>
@@ -24,6 +26,7 @@
 #include <video/mipi_display.h>
 #include <video/videomode.h>
 
+#include "exynos_drm_crtc.h"
 #include "exynos_drm_drv.h"
 
 /* returns true iff both arguments logically differs */
@@ -247,6 +250,7 @@ struct exynos_dsi {
 	struct clk *bus_clk;
 	struct regulator_bulk_data supplies[2];
 	int irq;
+	int te_gpio;
 
 	u32 pll_clk_rate;
 	u32 burst_clk_rate;
@@ -954,17 +958,89 @@ static irqreturn_t exynos_dsi_irq(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t exynos_dsi_te_irq_handler(int irq, void *dev_id)
+{
+	struct exynos_dsi *dsi = (struct exynos_dsi *)dev_id;
+	struct drm_encoder *encoder = dsi->encoder;
+
+	if (dsi->state & DSIM_STATE_ENABLED)
+		exynos_drm_crtc_te_handler(encoder->crtc);
+
+	return IRQ_HANDLED;
+}
+
+static void exynos_dsi_enable_irq(struct exynos_dsi *dsi)
+{
+	enable_irq(dsi->irq);
+
+	if (gpio_is_valid(dsi->te_gpio))
+		enable_irq(gpio_to_irq(dsi->te_gpio));
+}
+
+static void exynos_dsi_disable_irq(struct exynos_dsi *dsi)
+{
+	if (gpio_is_valid(dsi->te_gpio))
+		disable_irq(gpio_to_irq(dsi->te_gpio));
+
+	disable_irq(dsi->irq);
+}
+
 static int exynos_dsi_init(struct exynos_dsi *dsi)
 {
 	exynos_dsi_enable_clock(dsi);
 	exynos_dsi_reset(dsi);
-	enable_irq(dsi->irq);
+	exynos_dsi_enable_irq(dsi);
 	exynos_dsi_wait_for_reset(dsi);
 	exynos_dsi_init_link(dsi);
 
 	return 0;
 }
 
+static int exynos_dsi_register_te_irq(struct exynos_dsi *dsi)
+{
+	int ret;
+
+	dsi->te_gpio = of_get_named_gpio(dsi->panel_node, "te-gpios", 0);
+	if (!gpio_is_valid(dsi->te_gpio)) {
+		dev_err(dsi->dev, "no te-gpios specified\n");
+		ret = dsi->te_gpio;
+		goto out;
+	}
+
+	ret = gpio_request_one(dsi->te_gpio, GPIOF_IN, "te_gpio");
+	if (ret) {
+		dev_err(dsi->dev, "gpio request failed with %d\n", ret);
+		goto out;
+	}
+
+	/*
+	 * This TE GPIO IRQ should not be set to IRQ_NOAUTOEN, because panel
+	 * calls drm_panel_init() first then calls mipi_dsi_attach() in probe().
+	 * It means that te_gpio is invalid when exynos_dsi_enable_irq() is
+	 * called by drm_panel_init() before panel is attached.
+	 */
+	ret = request_threaded_irq(gpio_to_irq(dsi->te_gpio),
+					exynos_dsi_te_irq_handler, NULL,
+					IRQF_TRIGGER_RISING, "TE", dsi);
+	if (ret) {
+		dev_err(dsi->dev, "request interrupt failed with %d\n", ret);
+		gpio_free(dsi->te_gpio);
+		goto out;
+	}
+
+out:
+	return ret;
+}
+
+static void exynos_dsi_unregister_te_irq(struct exynos_dsi *dsi)
+{
+	if (gpio_is_valid(dsi->te_gpio)) {
+		free_irq(gpio_to_irq(dsi->te_gpio), dsi);
+		gpio_free(dsi->te_gpio);
+		dsi->te_gpio = -ENOENT;
+	}
+}
+
 static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
 				  struct mipi_dsi_device *device)
 {
@@ -978,6 +1054,16 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
 	if (dsi->connector.dev)
 		drm_helper_hpd_irq_event(dsi->connector.dev);
 
+	/*
+	 * If attached panel device is for command mode one, dsi should
+	 * register TE interrupt handler.
+	 */
+	if (!(dsi->mode_flags & MIPI_DSI_MODE_VIDEO)) {
+		int ret = exynos_dsi_register_te_irq(dsi);
+		if (ret)
+			return ret;
+	}
+
 	return 0;
 }
 
@@ -986,6 +1072,8 @@ static int exynos_dsi_host_detach(struct mipi_dsi_host *host,
 {
 	struct exynos_dsi *dsi = host_to_dsi(host);
 
+	exynos_dsi_unregister_te_irq(dsi);
+
 	dsi->panel_node = NULL;
 
 	if (dsi->connector.dev)
@@ -1099,7 +1187,7 @@ static void exynos_dsi_poweroff(struct exynos_dsi *dsi)
 
 		exynos_dsi_disable_clock(dsi);
 
-		disable_irq(dsi->irq);
+		exynos_dsi_disable_irq(dsi);
 	}
 
 	dsi->state &= ~DSIM_STATE_CMD_LPM;
@@ -1445,6 +1533,9 @@ static int exynos_dsi_probe(struct platform_device *pdev)
 		goto err_del_component;
 	}
 
+	/* To be checked as invalid one */
+	dsi->te_gpio = -ENOENT;
+
 	init_completion(&dsi->completed);
 	spin_lock_init(&dsi->transfer_lock);
 	INIT_LIST_HEAD(&dsi->transfer_list);
-- 
1.9.0