drm/exynos: mic: add MIC driver

MIC(Mobile image compressor) is newly added IP in Exynos5433. MIC
resides between decon and mipi dsim, and compresses frame data by 50%.
With dsi, not display port, to send frame data to the panel, the
bandwidth is not enough. That is why this compressor is introduced.

Signed-off-by: Hyungwon Hwang <[e-mail]>
Signed-off-by: Inki Dae <[e-mail]>

Documentation/devicetree/bindings/video/exynos-mic.txt

···
+Device-Tree bindings for Samsung Exynos SoC mobile image compressor (MIC)
+
+MIC (mobile image compressor) resides between decon and mipi dsi. Mipi dsi is
+not capable to transfer high resoltuion frame data as decon can send. MIC
+solves this problem by compressing the frame data by 1/2 before it is
+transferred through mipi dsi. The compressed frame data must be uncompressed in
+the panel PCB.
+
+Required properties:
+- compatible: value should be "samsung,exynos5433-mic".
+- reg: physical base address and length of the MIC registers set and system
+       register of mic.
+- clocks: must include clock specifiers corresponding to entries in the
+	  clock-names property.
+- clock-names: list of clock names sorted in the same order as the clocks
+	       property. Must contain "pclk_mic0", "sclk_rgb_vclk_to_mic0".
+- samsung,disp-syscon: the reference node for syscon for DISP block.
+- ports: contains a port which is connected to decon node and dsi node.
+	 address-cells and size-cells must 1 and 0, respectively.
+- port: contains an endpoint node which is connected to the endpoint in the
+	decon node or dsi node. The reg value must be 0 and 1 respectively.
+
+Example:
+SoC specific DT entry:
+mic: mic@13930000 {
+	compatible = "samsung,exynos5433-mic";
+	reg = <0x13930000 0x48>;
+	clocks = <&cmu_disp CLK_PCLK_MIC0>,
+	       <&cmu_disp CLK_SCLK_RGB_VCLK_TO_MIC0>;
+	clock-names = "pclk_mic0", "sclk_rgb_vclk_to_mic0";
+	samsung,disp-syscon = <&syscon_disp>;
+
+	ports {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		port@0 {
+			reg = <0>;
+			mic_to_decon: endpoint {
+				remote-endpoint = <&decon_to_mic>;
+			};
+		};
+
+		port@1 {
+			reg = <1>;
+			mic_to_dsi: endpoint {
+				remote-endpoint = <&dsi_to_mic>;
+			};
+		};
+	};
+};

drivers/gpu/drm/exynos/Kconfig

···
 	depends on DRM_EXYNOS_IPP && ARCH_EXYNOS5 && !ARCH_MULTIPLATFORM
 	help
 	  Choose this option if you want to use Exynos GSC for DRM.
+
+config DRM_EXYNOS_MIC
+	bool "Exynos DRM MIC"
+	depends on (DRM_EXYNOS && DRM_EXYNOS5433_DECON)
+	help
+	  Choose this option if you want to use Exynos MIC for DRM.

drivers/gpu/drm/exynos/Makefile

···
 exynosdrm-$(CONFIG_DRM_EXYNOS_FIMC)	+= exynos_drm_fimc.o
 exynosdrm-$(CONFIG_DRM_EXYNOS_ROTATOR)	+= exynos_drm_rotator.o
 exynosdrm-$(CONFIG_DRM_EXYNOS_GSC)	+= exynos_drm_gsc.o
+exynosdrm-$(CONFIG_DRM_EXYNOS_MIC)     += exynos_drm_mic.o
 
 obj-$(CONFIG_DRM_EXYNOS)		+= exynosdrm.o

drivers/gpu/drm/exynos/exynos_drm_drv.c

···
 #ifdef CONFIG_DRM_EXYNOS7_DECON
 	&decon_driver,
 #endif
+#ifdef CONFIG_DRM_EXYNOS_MIC
+	&mic_driver,
+#endif
 #ifdef CONFIG_DRM_EXYNOS_DP
 	&dp_driver,
 #endif
···
 };
 
 static struct platform_driver *const exynos_drm_non_kms_drivers[] = {
-#ifdef CONFIG_DRM_EXYNOS_MIC
-	&mic_driver,
-#endif
 #ifdef CONFIG_DRM_EXYNOS_G2D
 	&g2d_driver,
 #endif

drivers/gpu/drm/exynos/exynos_drm_drv.h

···
 extern struct platform_driver rotator_driver;
 extern struct platform_driver gsc_driver;
 extern struct platform_driver ipp_driver;
+extern struct platform_driver mic_driver;
 #endif

drivers/gpu/drm/exynos/exynos_drm_mic.c

···
+/*
+ * Copyright (C) 2015 Samsung Electronics Co.Ltd
+ * Authors:
+ *	Hyungwon Hwang <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundationr
+ */
+
+#include <linux/platform_device.h>
+#include <video/of_videomode.h>
+#include <linux/of_address.h>
+#include <video/videomode.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/clk.h>
+#include <drm/drmP.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+
+/* Sysreg registers for MIC */
+#define DSD_CFG_MUX	0x1004
+#define MIC0_RGB_MUX	(1 << 0)
+#define MIC0_I80_MUX	(1 << 1)
+#define MIC0_ON_MUX	(1 << 5)
+
+/* MIC registers */
+#define MIC_OP				0x0
+#define MIC_IP_VER			0x0004
+#define MIC_V_TIMING_0			0x0008
+#define MIC_V_TIMING_1			0x000C
+#define MIC_IMG_SIZE			0x0010
+#define MIC_INPUT_TIMING_0		0x0014
+#define MIC_INPUT_TIMING_1		0x0018
+#define MIC_2D_OUTPUT_TIMING_0		0x001C
+#define MIC_2D_OUTPUT_TIMING_1		0x0020
+#define MIC_2D_OUTPUT_TIMING_2		0x0024
+#define MIC_3D_OUTPUT_TIMING_0		0x0028
+#define MIC_3D_OUTPUT_TIMING_1		0x002C
+#define MIC_3D_OUTPUT_TIMING_2		0x0030
+#define MIC_CORE_PARA_0			0x0034
+#define MIC_CORE_PARA_1			0x0038
+#define MIC_CTC_CTRL			0x0040
+#define MIC_RD_DATA			0x0044
+
+#define MIC_UPD_REG			(1 << 31)
+#define MIC_ON_REG			(1 << 30)
+#define MIC_TD_ON_REG			(1 << 29)
+#define MIC_BS_CHG_OUT			(1 << 16)
+#define MIC_VIDEO_TYPE(x)		(((x) & 0xf) << 12)
+#define MIC_PSR_EN			(1 << 5)
+#define MIC_SW_RST			(1 << 4)
+#define MIC_ALL_RST			(1 << 3)
+#define MIC_CORE_VER_CONTROL		(1 << 2)
+#define MIC_MODE_SEL_COMMAND_MODE	(1 << 1)
+#define MIC_MODE_SEL_MASK		(1 << 1)
+#define MIC_CORE_EN			(1 << 0)
+
+#define MIC_V_PULSE_WIDTH(x)		(((x) & 0x3fff) << 16)
+#define MIC_V_PERIOD_LINE(x)		((x) & 0x3fff)
+
+#define MIC_VBP_SIZE(x)			(((x) & 0x3fff) << 16)
+#define MIC_VFP_SIZE(x)			((x) & 0x3fff)
+
+#define MIC_IMG_V_SIZE(x)		(((x) & 0x3fff) << 16)
+#define MIC_IMG_H_SIZE(x)		((x) & 0x3fff)
+
+#define MIC_H_PULSE_WIDTH_IN(x)		(((x) & 0x3fff) << 16)
+#define MIC_H_PERIOD_PIXEL_IN(x)	((x) & 0x3fff)
+
+#define MIC_HBP_SIZE_IN(x)		(((x) & 0x3fff) << 16)
+#define MIC_HFP_SIZE_IN(x)		((x) & 0x3fff)
+
+#define MIC_H_PULSE_WIDTH_2D(x)		(((x) & 0x3fff) << 16)
+#define MIC_H_PERIOD_PIXEL_2D(x)	((x) & 0x3fff)
+
+#define MIC_HBP_SIZE_2D(x)		(((x) & 0x3fff) << 16)
+#define MIC_HFP_SIZE_2D(x)		((x) & 0x3fff)
+
+#define MIC_BS_SIZE_2D(x)	((x) & 0x3fff)
+
+enum {
+	ENDPOINT_DECON_NODE,
+	ENDPOINT_DSI_NODE,
+	NUM_ENDPOINTS
+};
+
+static char *clk_names[] = { "pclk_mic0", "sclk_rgb_vclk_to_mic0" };
+#define NUM_CLKS		ARRAY_SIZE(clk_names)
+static DEFINE_MUTEX(mic_mutex);
+
+struct exynos_mic {
+	struct device *dev;
+	void __iomem *reg;
+	struct regmap *sysreg;
+	struct clk *clks[NUM_CLKS];
+
+	bool i80_mode;
+	struct videomode vm;
+	struct drm_encoder *encoder;
+	struct drm_bridge bridge;
+
+	bool enabled;
+};
+
+static void mic_set_path(struct exynos_mic *mic, bool enable)
+{
+	int ret;
+	unsigned int val;
+
+	ret = regmap_read(mic->sysreg, DSD_CFG_MUX, &val);
+	if (ret) {
+		DRM_ERROR("mic: Failed to read system register\n");
+		return;
+	}
+
+	if (enable) {
+		if (mic->i80_mode)
+			val |= MIC0_I80_MUX;
+		else
+			val |= MIC0_RGB_MUX;
+
+		val |=  MIC0_ON_MUX;
+	} else
+		val &= ~(MIC0_RGB_MUX | MIC0_I80_MUX | MIC0_ON_MUX);
+
+	regmap_write(mic->sysreg, DSD_CFG_MUX, val);
+	if (ret)
+		DRM_ERROR("mic: Failed to read system register\n");
+}
+
+static int mic_sw_reset(struct exynos_mic *mic)
+{
+	unsigned int retry = 100;
+	int ret;
+
+	writel(MIC_SW_RST, mic->reg + MIC_OP);
+
+	while (retry-- > 0) {
+		ret = readl(mic->reg + MIC_OP);
+		if (!(ret & MIC_SW_RST))
+			return 0;
+
+		udelay(10);
+	}
+
+	return -ETIMEDOUT;
+}
+
+static void mic_set_porch_timing(struct exynos_mic *mic)
+{
+	struct videomode vm = mic->vm;
+	u32 reg;
+
+	reg = MIC_V_PULSE_WIDTH(vm.vsync_len) +
+		MIC_V_PERIOD_LINE(vm.vsync_len + vm.vactive +
+				vm.vback_porch + vm.vfront_porch);
+	writel(reg, mic->reg + MIC_V_TIMING_0);
+
+	reg = MIC_VBP_SIZE(vm.vback_porch) +
+		MIC_VFP_SIZE(vm.vfront_porch);
+	writel(reg, mic->reg + MIC_V_TIMING_1);
+
+	reg = MIC_V_PULSE_WIDTH(vm.hsync_len) +
+		MIC_V_PERIOD_LINE(vm.hsync_len + vm.hactive +
+				vm.hback_porch + vm.hfront_porch);
+	writel(reg, mic->reg + MIC_INPUT_TIMING_0);
+
+	reg = MIC_VBP_SIZE(vm.hback_porch) +
+		MIC_VFP_SIZE(vm.hfront_porch);
+	writel(reg, mic->reg + MIC_INPUT_TIMING_1);
+}
+
+static void mic_set_img_size(struct exynos_mic *mic)
+{
+	struct videomode *vm = &mic->vm;
+	u32 reg;
+
+	reg = MIC_IMG_H_SIZE(vm->hactive) +
+		MIC_IMG_V_SIZE(vm->vactive);
+
+	writel(reg, mic->reg + MIC_IMG_SIZE);
+}
+
+static void mic_set_output_timing(struct exynos_mic *mic)
+{
+	struct videomode vm = mic->vm;
+	u32 reg, bs_size_2d;
+
+	DRM_DEBUG("w: %u, h: %u\n", vm.hactive, vm.vactive);
+	bs_size_2d = ((vm.hactive >> 2) << 1) + (vm.vactive % 4);
+	reg = MIC_BS_SIZE_2D(bs_size_2d);
+	writel(reg, mic->reg + MIC_2D_OUTPUT_TIMING_2);
+
+	if (!mic->i80_mode) {
+		reg = MIC_H_PULSE_WIDTH_2D(vm.hsync_len) +
+			MIC_H_PERIOD_PIXEL_2D(vm.hsync_len + bs_size_2d +
+					vm.hback_porch + vm.hfront_porch);
+		writel(reg, mic->reg + MIC_2D_OUTPUT_TIMING_0);
+
+		reg = MIC_HBP_SIZE_2D(vm.hback_porch) +
+			MIC_H_PERIOD_PIXEL_2D(vm.hfront_porch);
+		writel(reg, mic->reg + MIC_2D_OUTPUT_TIMING_1);
+	}
+}
+
+static void mic_set_reg_on(struct exynos_mic *mic, bool enable)
+{
+	u32 reg = readl(mic->reg + MIC_OP);
+
+	if (enable) {
+		reg &= ~(MIC_MODE_SEL_MASK | MIC_CORE_VER_CONTROL | MIC_PSR_EN);
+		reg |= (MIC_CORE_EN | MIC_BS_CHG_OUT | MIC_ON_REG);
+
+		reg  &= ~MIC_MODE_SEL_COMMAND_MODE;
+		if (mic->i80_mode)
+			reg |= MIC_MODE_SEL_COMMAND_MODE;
+	} else {
+		reg &= ~MIC_CORE_EN;
+	}
+
+	reg |= MIC_UPD_REG;
+	writel(reg, mic->reg + MIC_OP);
+}
+
+static struct device_node *get_remote_node(struct device_node *from, int reg)
+{
+	struct device_node *endpoint = NULL, *remote_node = NULL;
+
+	endpoint = of_graph_get_endpoint_by_regs(from, reg, -1);
+	if (!endpoint) {
+		DRM_ERROR("mic: Failed to find remote port from %s",
+				from->full_name);
+		goto exit;
+	}
+
+	remote_node = of_graph_get_remote_port_parent(endpoint);
+	if (!remote_node) {
+		DRM_ERROR("mic: Failed to find remote port parent from %s",
+							from->full_name);
+		goto exit;
+	}
+
+exit:
+	of_node_put(endpoint);
+	return remote_node;
+}
+
+static int parse_dt(struct exynos_mic *mic)
+{
+	int ret = 0, i, j;
+	struct device_node *remote_node;
+	struct device_node *nodes[3];
+
+	/*
+	 * The order of endpoints does matter.
+	 * The first node must be for decon and the second one must be for dsi.
+	 */
+	for (i = 0, j = 0; i < NUM_ENDPOINTS; i++) {
+		remote_node = get_remote_node(mic->dev->of_node, i);
+		if (!remote_node) {
+			ret = -EPIPE;
+			goto exit;
+		}
+		nodes[j++] = remote_node;
+
+		switch (i) {
+		case ENDPOINT_DECON_NODE:
+			/* decon node */
+			if (of_get_child_by_name(remote_node,
+						"i80-if-timings"))
+				mic->i80_mode = 1;
+
+			break;
+		case ENDPOINT_DSI_NODE:
+			/* panel node */
+			remote_node = get_remote_node(remote_node, 1);
+			if (!remote_node) {
+				ret = -EPIPE;
+				goto exit;
+			}
+			nodes[j++] = remote_node;
+
+			ret = of_get_videomode(remote_node,
+							&mic->vm, 0);
+			if (ret) {
+				DRM_ERROR("mic: failed to get videomode");
+				goto exit;
+			}
+
+			break;
+		default:
+			DRM_ERROR("mic: Unknown endpoint from MIC");
+			break;
+		}
+	}
+
+exit:
+	while (--j > -1)
+		of_node_put(nodes[j]);
+
+	return ret;
+}
+
+void mic_disable(struct drm_bridge *bridge) { }
+
+void mic_post_disable(struct drm_bridge *bridge)
+{
+	struct exynos_mic *mic = bridge->driver_private;
+	int i;
+
+	mutex_lock(&mic_mutex);
+	if (!mic->enabled)
+		goto already_disabled;
+
+	mic_set_path(mic, 0);
+
+	for (i = NUM_CLKS - 1; i > -1; i--)
+		clk_disable_unprepare(mic->clks[i]);
+
+	mic->enabled = 0;
+
+already_disabled:
+	mutex_unlock(&mic_mutex);
+}
+
+void mic_pre_enable(struct drm_bridge *bridge)
+{
+	struct exynos_mic *mic = bridge->driver_private;
+	int ret, i;
+
+	mutex_lock(&mic_mutex);
+	if (mic->enabled)
+		goto already_enabled;
+
+	for (i = 0; i < NUM_CLKS; i++) {
+		ret = clk_prepare_enable(mic->clks[i]);
+		if (ret < 0) {
+			DRM_ERROR("Failed to enable clock (%s)\n",
+							clk_names[i]);
+			goto turn_off_clks;
+		}
+	}
+
+	mic_set_path(mic, 1);
+
+	ret = mic_sw_reset(mic);
+	if (ret) {
+		DRM_ERROR("Failed to reset\n");
+		goto turn_off_clks;
+	}
+
+	if (!mic->i80_mode)
+		mic_set_porch_timing(mic);
+	mic_set_img_size(mic);
+	mic_set_output_timing(mic);
+	mic_set_reg_on(mic, 1);
+	mic->enabled = 1;
+	mutex_unlock(&mic_mutex);
+
+	return;
+
+turn_off_clks:
+	while (--i > -1)
+		clk_disable_unprepare(mic->clks[i]);
+already_enabled:
+	mutex_unlock(&mic_mutex);
+}
+
+void mic_enable(struct drm_bridge *bridge) { }
+
+void mic_destroy(struct drm_bridge *bridge)
+{
+	struct exynos_mic *mic = bridge->driver_private;
+	int i;
+
+	mutex_lock(&mic_mutex);
+	if (!mic->enabled)
+		goto already_disabled;
+
+	for (i = NUM_CLKS - 1; i > -1; i--)
+		clk_disable_unprepare(mic->clks[i]);
+
+already_disabled:
+	mutex_unlock(&mic_mutex);
+}
+
+struct drm_bridge_funcs mic_bridge_funcs = {
+	.disable = mic_disable,
+	.post_disable = mic_post_disable,
+	.pre_enable = mic_pre_enable,
+	.enable = mic_enable,
+};
+
+int exynos_mic_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct exynos_mic *mic;
+	struct resource res;
+	int ret, i;
+
+	mic = devm_kzalloc(dev, sizeof(*mic), GFP_KERNEL);
+	if (!mic) {
+		DRM_ERROR("mic: Failed to allocate memory for MIC object\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	mic->dev = dev;
+
+	ret = parse_dt(mic);
+	if (ret)
+		goto err;
+
+	ret = of_address_to_resource(dev->of_node, 0, &res);
+	if (ret) {
+		DRM_ERROR("mic: Failed to get mem region for MIC\n");
+		goto err;
+	}
+	mic->reg = devm_ioremap(dev, res.start, resource_size(&res));
+	if (!mic->reg) {
+		DRM_ERROR("mic: Failed to remap for MIC\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	mic->sysreg = syscon_regmap_lookup_by_phandle(dev->of_node,
+							"samsung,disp-syscon");
+	if (IS_ERR(mic->sysreg)) {
+		DRM_ERROR("mic: Failed to get system register.\n");
+		goto err;
+	}
+
+	mic->bridge.funcs = &mic_bridge_funcs;
+	mic->bridge.of_node = dev->of_node;
+	mic->bridge.driver_private = mic;
+	ret = drm_bridge_add(&mic->bridge);
+	if (ret) {
+		DRM_ERROR("mic: Failed to add MIC to the global bridge list\n");
+		goto err;
+	}
+
+	for (i = 0; i < NUM_CLKS; i++) {
+		mic->clks[i] = of_clk_get_by_name(dev->of_node, clk_names[i]);
+		if (IS_ERR(mic->clks[i])) {
+			DRM_ERROR("mic: Failed to get clock (%s)\n",
+								clk_names[i]);
+			ret = PTR_ERR(mic->clks[i]);
+			goto err;
+		}
+	}
+
+	DRM_DEBUG_KMS("MIC has been probed\n");
+
+err:
+	return ret;
+}
+
+static int exynos_mic_remove(struct platform_device *pdev)
+{
+	struct exynos_mic *mic = platform_get_drvdata(pdev);
+	int i;
+
+	drm_bridge_remove(&mic->bridge);
+
+	for (i = NUM_CLKS - 1; i > -1; i--)
+		clk_put(mic->clks[i]);
+
+	return 0;
+}
+
+static const struct of_device_id exynos_mic_of_match[] = {
+	{ .compatible = "samsung,exynos5433-mic" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, exynos_mic_of_match);
+
+struct platform_driver mic_driver = {
+	.probe		= exynos_mic_probe,
+	.remove		= exynos_mic_remove,
+	.driver		= {
+		.name	= "exynos-mic",
+		.owner	= THIS_MODULE,
+		.of_match_table = exynos_mic_of_match,
+	},
+};