[LINUX PATCH 2/2] drm: xlnx: dsi: driver for Xilinx DSI Tx subsystem

[Venkateshwar Rao Gannavarapu <venkateshwar.rao.gannavarapu@xilinx.com>]

The Xilinx MIPI DSI Tx Subsystem soft IP is used to display video
data from AXI-4 stream interface.

It supports upto 4 lanes, optional register interface for the DPHY
and multiple RGB color formats.
This is a MIPI-DSI host driver and provides DSI bus for panels.
This driver also helps to communicate with its panel using panel
framework.

Signed-off-by: Venkateshwar Rao Gannavarapu <venkateshwar.rao.gannavarapu@xilinx.com>
---
 drivers/gpu/drm/xlnx/Kconfig    |  14 ++
 drivers/gpu/drm/xlnx/Makefile   |   1 +
 drivers/gpu/drm/xlnx/xlnx_dsi.c | 456 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 471 insertions(+)
 create mode 100644 drivers/gpu/drm/xlnx/xlnx_dsi.c

diff --git a/drivers/gpu/drm/xlnx/Kconfig b/drivers/gpu/drm/xlnx/Kconfig
index c3d0826..caa632b 100644
--- a/drivers/gpu/drm/xlnx/Kconfig
+++ b/drivers/gpu/drm/xlnx/Kconfig
@@ -14,3 +14,17 @@ config DRM_ZYNQMP_DPSUB
 	  This is a DRM/KMS driver for ZynqMP DisplayPort controller. Choose
 	  this option if you have a Xilinx ZynqMP SoC with DisplayPort
 	  subsystem.
+
+config DRM_XLNX_DSI
+	tristate "Xilinx DRM DSI Subsystem Driver"
+	depends on DRM && OF
+	select DRM_KMS_HELPER
+	select DRM_MIPI_DSI
+	select DRM_PANEL
+	select BACKLIGHT_LCD_SUPPORT
+	select BACKLIGHT_CLASS_DEVICE
+	select DRM_PANEL_SIMPLE
+	help
+	  DRM bridge driver for Xilinx programmable DSI subsystem controller.
+	  choose this option if you hava a Xilinx MIPI-DSI Tx subsytem in
+	  video pipeline.
diff --git a/drivers/gpu/drm/xlnx/Makefile b/drivers/gpu/drm/xlnx/Makefile
index 51c24b7..1e97fbe 100644
--- a/drivers/gpu/drm/xlnx/Makefile
+++ b/drivers/gpu/drm/xlnx/Makefile
@@ -1,2 +1,3 @@
 zynqmp-dpsub-y := zynqmp_disp.o zynqmp_dpsub.o zynqmp_dp.o
 obj-$(CONFIG_DRM_ZYNQMP_DPSUB) += zynqmp-dpsub.o
+obj-$(CONFIG_DRM_XLNX_DSI) += xlnx_dsi.o
diff --git a/drivers/gpu/drm/xlnx/xlnx_dsi.c b/drivers/gpu/drm/xlnx/xlnx_dsi.c
new file mode 100644
index 0000000..a5291f3
--- /dev/null
+++ b/drivers/gpu/drm/xlnx/xlnx_dsi.c
@@ -0,0 +1,456 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * Xilinx FPGA MIPI DSI Tx Controller driver.
+ *
+ * Copyright (C) 2022 Xilinx, Inc.
+ *
+ * Author: Venkateshwar Rao G <vgannava@xilinx.com>
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_of.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_print.h>
+
+/* DSI Tx IP registers */
+#define XDSI_CCR			0x00
+#define XDSI_CCR_COREENB		BIT(0)
+#define XDSI_CCR_SOFTRST		BIT(1)
+#define XDSI_CCR_CRREADY		BIT(2)
+#define XDSI_CCR_CMDMODE		BIT(3)
+#define XDSI_CCR_DFIFORST		BIT(4)
+#define XDSI_CCR_CMDFIFORST		BIT(5)
+#define XDSI_PCR			0x04
+#define XDSI_PCR_LANES_MASK		3
+#define XDSI_PCR_VIDEOMODE(x)		(((x) & 0x3) << 3)
+#define XDSI_PCR_VIDEOMODE_MASK		(0x3 << 3)
+#define XDSI_PCR_VIDEOMODE_SHIFT	3
+#define XDSI_PCR_BLLPTYPE(x)		((x) << 5)
+#define XDSI_PCR_BLLPMODE(x)		((x) << 6)
+#define XDSI_PCR_PIXELFORMAT_MASK	(0x3 << 11)
+#define XDSI_PCR_PIXELFORMAT_SHIFT	11
+#define XDSI_PCR_EOTPENABLE(x)		((x) << 13)
+#define XDSI_GIER			0x20
+#define XDSI_ISR			0x24
+#define XDSI_IER			0x28
+#define XDSI_STR			0x2C
+#define XDSI_STR_RDY_SHPKT		BIT(6)
+#define XDSI_STR_RDY_LNGPKT		BIT(7)
+#define XDSI_STR_DFIFO_FULL		BIT(8)
+#define XDSI_STR_DFIFO_EMPTY		BIT(9)
+#define XDSI_STR_WAITFR_DATA		BIT(10)
+#define XDSI_STR_CMD_EXE_PGS		BIT(11)
+#define XDSI_STR_CCMD_PROC		BIT(12)
+#define XDSI_STR_LPKT_MASK		(0x5 << 7)
+#define XDSI_CMD			0x30
+#define XDSI_CMD_QUEUE_PACKET(x)	((x) & GENMASK(23, 0))
+#define XDSI_DFR			0x34
+#define XDSI_TIME1			0x50
+#define XDSI_TIME1_BLLP_BURST(x)	((x) & GENMASK(15, 0))
+#define XDSI_TIME1_HSA(x)		(((x) & GENMASK(15, 0)) << 16)
+#define XDSI_TIME2			0x54
+#define XDSI_TIME2_VACT(x)		((x) & GENMASK(15, 0))
+#define XDSI_TIME2_HACT(x)		(((x) & GENMASK(15, 0)) << 16)
+#define XDSI_HACT_MULTIPLIER		GENMASK(1, 0)
+#define XDSI_TIME3			0x58
+#define XDSI_TIME3_HFP(x)		((x) & GENMASK(15, 0))
+#define XDSI_TIME3_HBP(x)		(((x) & GENMASK(15, 0)) << 16)
+#define XDSI_TIME4			0x5c
+#define XDSI_TIME4_VFP(x)		((x) & GENMASK(7, 0))
+#define XDSI_TIME4_VBP(x)		(((x) & GENMASK(7, 0)) << 8)
+#define XDSI_TIME4_VSA(x)		(((x) & GENMASK(7, 0)) << 16)
+#define XDSI_NUM_DATA_T			4
+
+/**
+ * struct xlnx_dsi - Xilinx DSI-TX core
+ * @bridge: DRM bridge structure
+ * @dsi_host: DSI host device
+ * @panel_bridge: Panel bridge structure
+ * @panel:  DRM panel structure
+ * @dev: device structure
+ * @clks: clock source structure
+ * @iomem: Base address of DSI subsystem
+ * @mode_flags: DSI operation mode related flags
+ * @lanes: number of active data lanes supported by DSI controller
+ * @mul_factor: multiplication factor for HACT timing
+ * @format: pixel format for video mode of DSI controller
+ * @device_found: Flag to indicate device presence
+ */
+struct xlnx_dsi {
+	struct drm_bridge bridge;
+	struct mipi_dsi_host dsi_host;
+	struct drm_bridge *panel_bridge;
+	struct drm_panel *panel;
+	struct device *dev;
+	struct clk_bulk_data *clks;
+	void __iomem *iomem;
+	unsigned long mode_flags;
+	u32 lanes;
+	u32 mul_factor;
+	enum mipi_dsi_pixel_format format;
+	bool device_found;
+};
+
+static const struct clk_bulk_data xdsi_clks[] = {
+	{ .id = "s_axis_aclk" },
+	{ .id = "dphy_clk_200M" },
+};
+
+static inline struct xlnx_dsi *host_to_dsi(struct mipi_dsi_host *host)
+{
+	return container_of(host, struct xlnx_dsi, dsi_host);
+}
+
+static inline struct xlnx_dsi *bridge_to_dsi(struct drm_bridge *bridge)
+{
+	return container_of(bridge, struct xlnx_dsi, bridge);
+}
+
+static inline void xlnx_dsi_writel(void __iomem *base, int offset, u32 val)
+{
+	writel(val, base + offset);
+}
+
+static inline u32 xlnx_dsi_readl(void __iomem *base, int offset)
+{
+	return readl(base + offset);
+}
+
+static int xlnx_dsi_panel_or_bridge(struct xlnx_dsi *dsi,
+				    struct device_node *node)
+{
+	struct drm_bridge *panel_bridge;
+	struct drm_panel *panel;
+	struct device *dev = dsi->dev;
+	struct device_node *endpoint = dev->of_node;
+	int ret;
+
+	ret = drm_of_find_panel_or_bridge(endpoint, 1, 0, &panel, &panel_bridge);
+	if (ret < 0) {
+		dev_err(dsi->dev, "failed to find panel / bridge\n");
+		return ret;
+	}
+
+	if (panel) {
+		panel_bridge = devm_drm_panel_bridge_add(dev, panel);
+		if (IS_ERR(panel_bridge))
+			return PTR_ERR(panel_bridge);
+		dsi->panel = panel;
+	}
+
+	dsi->panel_bridge = panel_bridge;
+
+	if (!dsi->panel_bridge) {
+		dev_err(dsi->dev, "panel not found\n");
+		return -EPROBE_DEFER;
+	}
+
+	return 0;
+}
+
+static int xlnx_dsi_host_attach(struct mipi_dsi_host *host,
+				struct mipi_dsi_device *device)
+{
+	struct xlnx_dsi *dsi = host_to_dsi(host);
+	u32 reg;
+
+	reg = xlnx_dsi_readl(dsi->iomem, XDSI_PCR);
+	dsi->lanes = reg & XDSI_PCR_LANES_MASK;
+	dsi->format = (reg & XDSI_PCR_PIXELFORMAT_MASK) >>
+		XDSI_PCR_PIXELFORMAT_SHIFT;
+	dsi->mode_flags = device->mode_flags;
+
+	if (dsi->lanes != device->lanes) {
+		dev_err(dsi->dev, "Mismatch of lanes. panel = %d, DSI = %d\n",
+			device->lanes, dsi->lanes);
+		return -EINVAL;
+	}
+
+	if (dsi->lanes > 4 || dsi->lanes < 1) {
+		dev_err(dsi->dev, "%d lanes : invalid xlnx,dsi-num-lanes\n",
+			dsi->lanes);
+		return -EINVAL;
+	}
+
+	if (dsi->format != device->format) {
+		dev_err(dsi->dev, "Mismatch of format. panel = %d, DSI = %d\n",
+			device->format, dsi->format);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int xlnx_dsi_host_detach(struct mipi_dsi_host *host,
+				struct mipi_dsi_device *device)
+{
+	struct xlnx_dsi *dsi = host_to_dsi(host);
+
+	if (dsi->panel) {
+		drm_panel_disable(dsi->panel);
+		dsi->panel = NULL;
+	}
+
+	return 0;
+}
+
+static const struct mipi_dsi_host_ops xlnx_dsi_ops = {
+	.attach = xlnx_dsi_host_attach,
+	.detach	= xlnx_dsi_host_detach,
+};
+
+static void
+xlnx_dsi_bridge_disable(struct drm_bridge *bridge,
+			struct drm_bridge_state *old_bridge_state)
+{
+	struct xlnx_dsi *dsi = bridge_to_dsi(bridge);
+	u32 reg = xlnx_dsi_readl(dsi->iomem, XDSI_CCR);
+
+	reg &= ~XDSI_CCR_COREENB;
+	xlnx_dsi_writel(dsi->iomem, XDSI_CCR, reg);
+	dev_dbg(dsi->dev, "DSI-Tx is disabled\n");
+}
+
+static void
+xlnx_dsi_bridge_mode_set(struct drm_bridge *bridge,
+			 const struct drm_display_mode *mode,
+			 const struct drm_display_mode *adjusted_mode)
+{
+	struct xlnx_dsi *dsi = bridge_to_dsi(bridge);
+	u32 reg, video_mode;
+
+	reg = xlnx_dsi_readl(dsi->iomem, XDSI_PCR);
+	video_mode = (reg & XDSI_PCR_VIDEOMODE_MASK) >> XDSI_PCR_VIDEOMODE_SHIFT;
+
+	if (!video_mode && (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)) {
+		reg = XDSI_TIME1_HSA(adjusted_mode->hsync_end -
+				     adjusted_mode->hsync_start);
+		xlnx_dsi_writel(dsi->iomem, XDSI_TIME1, reg);
+	}
+
+	reg = XDSI_TIME4_VFP(adjusted_mode->vsync_start -
+			     adjusted_mode->vdisplay) |
+		XDSI_TIME4_VBP(adjusted_mode->vtotal -
+			       adjusted_mode->vsync_end) |
+		XDSI_TIME4_VSA(adjusted_mode->vsync_end -
+			       adjusted_mode->vsync_start);
+	xlnx_dsi_writel(dsi->iomem, XDSI_TIME4, reg);
+
+	reg = XDSI_TIME3_HFP(adjusted_mode->hsync_start -
+			     adjusted_mode->hdisplay) |
+		XDSI_TIME3_HBP(adjusted_mode->htotal -
+			       adjusted_mode->hsync_end);
+	xlnx_dsi_writel(dsi->iomem, XDSI_TIME3, reg);
+	dev_dbg(dsi->dev, "mul factor for parsed datatype is = %d\n",
+		(dsi->mul_factor) / 100);
+
+	if ((adjusted_mode->hdisplay & XDSI_HACT_MULTIPLIER) != 0)
+		dev_warn(dsi->dev, "Incorrect HACT will be programmed\n");
+
+	reg = XDSI_TIME2_HACT((adjusted_mode->hdisplay) * (dsi->mul_factor) / 100) |
+		XDSI_TIME2_VACT(adjusted_mode->vdisplay);
+
+	xlnx_dsi_writel(dsi->iomem, XDSI_PCR, XDSI_PCR_VIDEOMODE(BIT(0)));
+}
+
+static void xlnx_dsi_bridge_enable(struct drm_bridge *bridge,
+				   struct drm_bridge_state *old_bridge_state)
+{
+	struct xlnx_dsi *dsi = bridge_to_dsi(bridge);
+	u32 reg;
+
+	reg = xlnx_dsi_readl(dsi->iomem, XDSI_CCR);
+	reg |= XDSI_CCR_COREENB;
+	xlnx_dsi_writel(dsi->iomem, XDSI_CCR, reg);
+	dev_dbg(dsi->dev, "MIPI DSI Tx controller is enabled.\n");
+}
+
+static int xlnx_dsi_bridge_attach(struct drm_bridge *bridge,
+				  enum drm_bridge_attach_flags flags)
+{
+	struct xlnx_dsi *dsi = bridge_to_dsi(bridge);
+
+	if (!bridge->encoder) {
+		DRM_ERROR("Parent encoder object not found\n");
+		return -ENODEV;
+	}
+
+	/* Set the encoder type as caller does not know it */
+	bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
+
+	if (!dsi->device_found) {
+		int ret;
+
+		ret = xlnx_dsi_panel_or_bridge(dsi, dsi->dev->of_node);
+		if (ret) {
+			dev_err(dsi->dev, "dsi_panel_or_bridge failed\n");
+			return ret;
+		}
+
+		dsi->device_found = true;
+	}
+
+	/* Attach the panel-bridge to the dsi bridge */
+	return drm_bridge_attach(bridge->encoder, dsi->panel_bridge, bridge,
+				 flags);
+}
+
+static void xlnx_dsi_bridge_detach(struct drm_bridge *bridge)
+{
+	struct xlnx_dsi *dsi = bridge_to_dsi(bridge);
+
+	drm_of_panel_bridge_remove(dsi->dev->of_node, 1, 0);
+}
+
+static const struct drm_bridge_funcs xlnx_dsi_bridge_funcs = {
+	.mode_set	= xlnx_dsi_bridge_mode_set,
+	.atomic_enable	= xlnx_dsi_bridge_enable,
+	.atomic_disable	= xlnx_dsi_bridge_disable,
+	.attach		= xlnx_dsi_bridge_attach,
+	.detach		= xlnx_dsi_bridge_detach,
+};
+
+static int xlnx_dsi_parse_dt(struct xlnx_dsi *dsi)
+{
+	struct device *dev = dsi->dev;
+	struct device_node *node = dev->of_node;
+	int ret;
+	u32 datatype;
+	static const int xdsi_mul_fact[XDSI_NUM_DATA_T] = {300, 225, 225, 200};
+
+	/*
+	 * Used as a multiplication factor for HACT based on used
+	 * DSI data type.
+	 *
+	 * e.g. for RGB666_L datatype and 1920x1080 resolution,
+	 * the Hact (WC) would be as follows -
+	 * 1920 pixels * 18 bits per pixel / 8 bits per byte
+	 * = 1920 pixels * 2.25 bytes per pixel = 4320 bytes.
+	 *
+	 * Data Type - Multiplication factor
+	 * RGB888    - 3
+	 * RGB666_L  - 2.25
+-	 * RGB666_P  - 2.25
+	 * RGB565    - 2
+	 *
+	 * Since the multiplication factor is a floating number,
+	 * a 100x multiplication factor is used.
+	 */
+	ret = of_property_read_u32(node, "xlnx,dsi-data-type", &datatype);
+	if (ret < 0) {
+		dev_err(dsi->dev, "missing xlnx,dsi-data-type property\n");
+		return ret;
+	}
+	dsi->format = datatype;
+	if (datatype > MIPI_DSI_FMT_RGB565) {
+		dev_err(dsi->dev, "Invalid xlnx,dsi-data-type string\n");
+		return -EINVAL;
+	}
+	dsi->mul_factor = xdsi_mul_fact[datatype];
+
+	dev_dbg(dsi->dev, "DSI controller num lanes = %d", dsi->lanes);
+	dev_dbg(dsi->dev, "DSI controller datatype = %d\n", datatype);
+
+	return 0;
+}
+
+static int xlnx_dsi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct resource *res;
+	struct xlnx_dsi *dsi;
+	int num_clks = ARRAY_SIZE(xdsi_clks);
+	int ret;
+
+	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
+	if (!dsi)
+		return -ENOMEM;
+
+	dsi->dev = dev;
+	dsi->clks = devm_kmemdup(dev, xdsi_clks, sizeof(xdsi_clks),
+				 GFP_KERNEL);
+	if (!dsi->clks)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dsi->iomem = devm_ioremap_resource(dev, res);
+	if (IS_ERR(dsi->iomem))
+		return PTR_ERR(dsi->iomem);
+
+	ret = clk_bulk_get(dev, num_clks, dsi->clks);
+	if (ret)
+		return ret;
+
+	ret = xlnx_dsi_parse_dt(dsi);
+	if (ret)
+		return ret;
+
+	ret = clk_bulk_prepare_enable(num_clks, dsi->clks);
+	if (ret)
+		goto err_clk_put;
+
+	platform_set_drvdata(pdev, dsi);
+	dsi->dsi_host.ops = &xlnx_dsi_ops;
+	dsi->dsi_host.dev = dev;
+
+	ret = mipi_dsi_host_register(&dsi->dsi_host);
+	if (ret) {
+		dev_err(dev, "Failed to register MIPI host: %d\n", ret);
+		goto err_clk_put;
+	}
+
+	dsi->bridge.driver_private = dsi;
+	dsi->bridge.funcs = &xlnx_dsi_bridge_funcs;
+#ifdef CONFIG_OF
+	dsi->bridge.of_node = pdev->dev.of_node;
+#endif
+
+	drm_bridge_add(&dsi->bridge);
+
+err_clk_put:
+	clk_bulk_put(num_clks, dsi->clks);
+
+	return ret;
+}
+
+static int xlnx_dsi_remove(struct platform_device *pdev)
+{
+	struct xlnx_dsi *dsi = platform_get_drvdata(pdev);
+	int num_clks = ARRAY_SIZE(xdsi_clks);
+
+	mipi_dsi_host_unregister(&dsi->dsi_host);
+	clk_bulk_disable_unprepare(num_clks, dsi->clks);
+	clk_bulk_put(num_clks, dsi->clks);
+
+	return 0;
+}
+
+static const struct of_device_id xlnx_dsi_of_match[] = {
+	{ .compatible = "xlnx,dsi-tx-v2.0"},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, xlnx_dsi_of_match);
+
+static struct platform_driver dsi_driver = {
+	.probe = xlnx_dsi_probe,
+	.remove = xlnx_dsi_remove,
+	.driver = {
+		.name = "xlnx-dsi",
+		.of_match_table = xlnx_dsi_of_match,
+	},
+};
+
+module_platform_driver(dsi_driver);
+
+MODULE_AUTHOR("Venkateshwar Rao G <vgannava@xilinx.com>");
+MODULE_DESCRIPTION("Xilinx MIPI DSI host controller driver");
+MODULE_LICENSE("GPL");
--
1.8.3.1