drm/mediatek: set dpi pin mode to gpio low to avoid leakage current

Config dpi pins mode to output and pull low when dpi is disabled.
Aovid leakage current from some dpi pins (Hsync Vsync DE ... ).
Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

drivers/gpu/drm/mediatek/mtk_dpi.c

@@ -10,7 +10,9 @@
 #include <linux/kernel.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_gpio.h>
 #include <linux/of_graph.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
 
@@ -74,6 +76,9 @@ struct mtk_dpi {
 	enum mtk_dpi_out_yc_map yc_map;
 	enum mtk_dpi_out_bit_num bit_num;
 	enum mtk_dpi_out_channel_swap channel_swap;
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pins_gpio;
+	struct pinctrl_state *pins_dpi;
 	int refcount;
 };
 
@@ -379,6 +384,9 @@ static void mtk_dpi_power_off(struct mtk_dpi *dpi)
 	if (--dpi->refcount != 0)
 		return;
 
+	if (dpi->pinctrl && dpi->pins_gpio)
+		pinctrl_select_state(dpi->pinctrl, dpi->pins_gpio);
+
 	mtk_dpi_disable(dpi);
 	clk_disable_unprepare(dpi->pixel_clk);
 	clk_disable_unprepare(dpi->engine_clk);
@@ -403,6 +411,9 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi)
 		goto err_pixel;
 	}
 
+	if (dpi->pinctrl && dpi->pins_dpi)
+		pinctrl_select_state(dpi->pinctrl, dpi->pins_dpi);
+
 	mtk_dpi_enable(dpi);
 	return 0;
 
@@ -705,6 +716,26 @@ static int mtk_dpi_probe(struct platform_device *pdev)
 	dpi->dev = dev;
 	dpi->conf = (struct mtk_dpi_conf *)of_device_get_match_data(dev);
 
+	dpi->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(dpi->pinctrl)) {
+		dpi->pinctrl = NULL;
+		dev_dbg(&pdev->dev, "Cannot find pinctrl!\n");
+	}
+	if (dpi->pinctrl) {
+		dpi->pins_gpio = pinctrl_lookup_state(dpi->pinctrl, "sleep");
+		if (IS_ERR(dpi->pins_gpio)) {
+			dpi->pins_gpio = NULL;
+			dev_dbg(&pdev->dev, "Cannot find pinctrl idle!\n");
+		}
+		if (dpi->pins_gpio)
+			pinctrl_select_state(dpi->pinctrl, dpi->pins_gpio);
+
+		dpi->pins_dpi = pinctrl_lookup_state(dpi->pinctrl, "default");
+		if (IS_ERR(dpi->pins_dpi)) {
+			dpi->pins_dpi = NULL;
+			dev_dbg(&pdev->dev, "Cannot find pinctrl active!\n");
+		}
+	}
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	dpi->regs = devm_ioremap_resource(dev, mem);
 	if (IS_ERR(dpi->regs)) {