[PATCH v2 14/19] drm: rcar-du: Add support for CMM

[Jacopo Mondi]

Add a driver for the R-Car Display Unit Color Correction Module.

In most of Gen3 SoCs, each DU output channel is provided with a CMM unit
to perform image enhancement and color correction.

Add support for CMM through a driver that supports configuration of
the 1-dimensional LUT table. More advanced CMM feature will be
implemented on top of this basic one.

Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
---
 drivers/gpu/drm/rcar-du/Kconfig    |   7 +
 drivers/gpu/drm/rcar-du/Makefile   |   1 +
 drivers/gpu/drm/rcar-du/rcar_cmm.c | 292 +++++++++++++++++++++++++++++
 drivers/gpu/drm/rcar-du/rcar_cmm.h |  38 ++++
 4 files changed, 338 insertions(+)
 create mode 100644 drivers/gpu/drm/rcar-du/rcar_cmm.c
 create mode 100644 drivers/gpu/drm/rcar-du/rcar_cmm.h

diff --git a/drivers/gpu/drm/rcar-du/Kconfig b/drivers/gpu/drm/rcar-du/Kconfig
index 1529849e217e..539d232790d1 100644
--- a/drivers/gpu/drm/rcar-du/Kconfig
+++ b/drivers/gpu/drm/rcar-du/Kconfig
@@ -13,6 +13,13 @@ config DRM_RCAR_DU
 	  Choose this option if you have an R-Car chipset.
 	  If M is selected the module will be called rcar-du-drm.
 
+config DRM_RCAR_CMM
+	bool "R-Car DU Color Management Module (CMM) Support"
+	depends on DRM && OF
+	depends on DRM_RCAR_DU
+	help
+	  Enable support for R-Car Color Management Module (CMM).
+
 config DRM_RCAR_DW_HDMI
 	tristate "R-Car DU Gen3 HDMI Encoder Support"
 	depends on DRM && OF
diff --git a/drivers/gpu/drm/rcar-du/Makefile b/drivers/gpu/drm/rcar-du/Makefile
index 6c2ed9c46467..4d1187ccc3e5 100644
--- a/drivers/gpu/drm/rcar-du/Makefile
+++ b/drivers/gpu/drm/rcar-du/Makefile
@@ -15,6 +15,7 @@ rcar-du-drm-$(CONFIG_DRM_RCAR_LVDS)	+= rcar_du_of.o \
 rcar-du-drm-$(CONFIG_DRM_RCAR_VSP)	+= rcar_du_vsp.o
 rcar-du-drm-$(CONFIG_DRM_RCAR_WRITEBACK) += rcar_du_writeback.o
 
+obj-$(CONFIG_DRM_RCAR_CMM)		+= rcar_cmm.o
 obj-$(CONFIG_DRM_RCAR_DU)		+= rcar-du-drm.o
 obj-$(CONFIG_DRM_RCAR_DW_HDMI)		+= rcar_dw_hdmi.o
 obj-$(CONFIG_DRM_RCAR_LVDS)		+= rcar_lvds.o
diff --git a/drivers/gpu/drm/rcar-du/rcar_cmm.c b/drivers/gpu/drm/rcar-du/rcar_cmm.c
new file mode 100644
index 000000000000..76ed3fce2b33
--- /dev/null
+++ b/drivers/gpu/drm/rcar-du/rcar_cmm.c
@@ -0,0 +1,292 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * rcar_cmm.c -- R-Car Display Unit Color Management Module
+ *
+ * Copyright (C) 2019 Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+
+#include <drm/drm_atomic.h>
+
+#include "rcar_cmm.h"
+
+#define CM2_LUT_CTRL		0x0000
+#define CM2_LUT_CTRL_EN		BIT(0)
+#define CM2_LUT_TBLA_BASE	0x0600
+#define CM2_LUT_TBLA(__i)	(CM2_LUT_TBLA_BASE + (__i) * 4)
+
+struct rcar_cmm {
+	struct clk *clk;
+	void __iomem *base;
+	bool enabled;
+
+	/*
+	 * restore: LUT restore flag
+	 * running: LUT operating flag
+	 * size: Number of programmed entries in the LUT table
+	 * table: Scratch buffer where to store the LUT table entries to be
+	 *	  later restored.
+	 */
+	struct {
+		bool restore;
+		bool running;
+		unsigned int size;
+		struct drm_color_lut table[CMM_GAMMA_LUT_SIZE];
+	} lut;
+};
+
+static inline int rcar_cmm_read(struct rcar_cmm *rcmm, u32 reg)
+{
+	return ioread32(rcmm->base + reg);
+}
+
+static inline void rcar_cmm_write(struct rcar_cmm *rcmm, u32 reg, u32 data)
+{
+	iowrite32(data, rcmm->base + reg);
+}
+
+static void rcar_cmm_lut_write(struct rcar_cmm *rcmm, unsigned int size,
+			       struct drm_color_lut *lut)
+{
+	unsigned int i;
+
+	for (i = 0; i < size; ++i) {
+		struct drm_color_lut *entry = &lut[i];
+
+		u32 val = (entry->red & 0xff) << 16 |
+			  (entry->green & 0xff) << 8 |
+			  (entry->blue & 0xff);
+		rcar_cmm_write(rcmm, CM2_LUT_TBLA(i), val);
+	}
+}
+
+/**
+ * rcar_cmm_setup() - configure the CMM unit
+ *
+ * @pdev: The platform device associated with the CMM instance
+ * @config: The CRTC provided configuration.
+ *
+ * Configure the CMM unit with the CRTC provided configuration.
+ * Currently enabling, disabling and programming of the 1-D LUT unit is
+ * supported.
+ */
+int rcar_cmm_setup(struct platform_device *pdev,
+		   const struct rcar_cmm_config *config)
+{
+	struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
+	unsigned int i;
+
+	if (config->lut.size > CMM_GAMMA_LUT_SIZE)
+		return -EINVAL;
+
+	/*
+	 * As cmm_setup is called by atomic commit tail helper, it might be
+	 * called before enabling the CRTC (which calls cmm_enable()).
+	 */
+	if (!rcmm->enabled) {
+		if (!config->lut.enable)
+			return 0;
+
+		/*
+		 * Store the LUT table entries in the scratch buffer to be later
+		 * programmed at enable time.
+		 */
+		for (i = 0; i < config->lut.size; ++i)
+			rcmm->lut.table[i] = config->lut.table[i];
+
+		rcmm->lut.size = config->lut.size;
+		rcmm->lut.restore = true;
+
+		return 0;
+	}
+
+	/* Stop LUT operations, if requested. */
+	if (rcmm->lut.running && !config->lut.enable) {
+		rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0);
+		rcmm->lut.running = 0;
+		rcmm->lut.size = 0;
+
+		return 0;
+	}
+
+	/* Enable LUT and program the new gamma table values. */
+	if (!rcmm->lut.running) {
+		rcar_cmm_write(rcmm, CM2_LUT_CTRL, CM2_LUT_CTRL_EN);
+		rcmm->lut.running = true;
+	}
+
+	rcar_cmm_lut_write(rcmm, config->lut.size, config->lut.table);
+	rcmm->lut.size = config->lut.size;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(rcar_cmm_setup);
+
+/**
+ * rcar_cmm_enable - enable the CMM unit
+ *
+ * @pdev: The platform device associated with the CMM instance
+ *
+ * Enable the CMM unit by enabling the parent clock and enabling the CMM
+ * components, such as 1-D LUT, if requested.
+ */
+int rcar_cmm_enable(struct platform_device *pdev)
+{
+	struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
+	int ret;
+
+	if (!rcmm)
+		return -EPROBE_DEFER;
+
+	ret = clk_prepare_enable(rcmm->clk);
+	if (ret)
+		return ret;
+
+	/* Apply the LUT table values saved at cmm_setup time. */
+	if (rcmm->lut.restore) {
+		rcar_cmm_write(rcmm, CM2_LUT_CTRL, CM2_LUT_CTRL_EN);
+		rcar_cmm_lut_write(rcmm, rcmm->lut.size, rcmm->lut.table);
+
+		rcmm->lut.restore = false;
+		rcmm->lut.running = true;
+	}
+
+	rcmm->enabled = true;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(rcar_cmm_enable);
+
+/**
+ * rcar_cmm_disable() - disable the CMM unit
+ *
+ * Disable the CMM unit by stopping the parent clock.
+ *
+ * @pdev: The platform device associated with the CMM instance
+ */
+void rcar_cmm_disable(struct platform_device *pdev)
+{
+	struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
+
+	rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0);
+
+	clk_disable_unprepare(rcmm->clk);
+
+	rcmm->lut.restore = false;
+	rcmm->lut.running = false;
+	rcmm->lut.size = 0;
+
+	rcmm->enabled = false;
+}
+EXPORT_SYMBOL_GPL(rcar_cmm_disable);
+
+#ifdef CONFIG_PM_SLEEP
+static int rcar_cmm_pm_suspend(struct device *dev)
+{
+	struct rcar_cmm *rcmm = dev_get_drvdata(dev);
+	unsigned int i;
+
+	if (!(rcmm->lut.running || rcmm->lut.restore))
+		return 0;
+
+	/* Save the LUT table entries in the scratch buffer table. */
+	for (i = 0; i < rcmm->lut.size; ++i) {
+		int entry = rcar_cmm_read(rcmm, CM2_LUT_TBLA(i));
+		struct drm_color_lut *lut = &rcmm->lut.table[i];
+
+		lut->blue = entry & 0xff;
+		lut->green = (entry >> 8) & 0xff;
+		lut->red = (entry >> 16) & 0xff;
+	}
+
+	rcmm->lut.restore = true;
+	rcmm->lut.running = false;
+
+	rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0);
+
+	return 0;
+}
+
+static int rcar_cmm_pm_resume(struct device *dev)
+{
+	struct rcar_cmm *rcmm = dev_get_drvdata(dev);
+
+	if (!rcmm->lut.restore)
+		return 0;
+
+	/* Program the LUT entries saved at suspend time. */
+	rcar_cmm_write(rcmm, CM2_LUT_CTRL, CM2_LUT_CTRL_EN);
+	rcar_cmm_lut_write(rcmm, rcmm->lut.size, rcmm->lut.table);
+	rcmm->lut.running = true;
+	rcmm->lut.restore = false;
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops rcar_cmm_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(rcar_cmm_pm_suspend, rcar_cmm_pm_resume)
+};
+
+static int rcar_cmm_probe(struct platform_device *pdev)
+{
+	struct rcar_cmm *rcmm;
+	struct resource *res;
+	resource_size_t size;
+
+	rcmm = devm_kzalloc(&pdev->dev, sizeof(*rcmm), GFP_KERNEL);
+	if (!rcmm)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, rcmm);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	size = resource_size(res);
+	if (!devm_request_mem_region(&pdev->dev, res->start, size,
+				     dev_name(&pdev->dev))) {
+		dev_err(&pdev->dev,
+			"can't request region for resource %pR\n", res);
+		return -EBUSY;
+	}
+
+	rcmm->base = devm_ioremap_nocache(&pdev->dev, res->start, size);
+	if (IS_ERR(rcmm->base))
+		return PTR_ERR(rcmm->base);
+
+	rcmm->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(rcmm->clk)) {
+		dev_err(&pdev->dev, "Failed to get CMM clock");
+		return PTR_ERR(rcmm->clk);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id rcar_cmm_of_table[] = {
+	{ .compatible = "renesas,rcar-gen3-cmm", },
+	{ .compatible = "renesas,rcar-gen2-cmm", },
+	{ },
+};
+
+MODULE_DEVICE_TABLE(of, rcar_cmm_of_table);
+
+static struct platform_driver rcar_cmm_platform_driver = {
+	.probe		= rcar_cmm_probe,
+	.driver		= {
+		.name	= "rcar-cmm",
+		.pm	= &rcar_cmm_pm_ops,
+		.of_match_table = rcar_cmm_of_table,
+	},
+};
+
+module_platform_driver(rcar_cmm_platform_driver);
+
+MODULE_AUTHOR("Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Renesas R-Car CMM Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/gpu/drm/rcar-du/rcar_cmm.h b/drivers/gpu/drm/rcar-du/rcar_cmm.h
new file mode 100644
index 000000000000..8744e72f32cd
--- /dev/null
+++ b/drivers/gpu/drm/rcar-du/rcar_cmm.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * rcar_cmm.h -- R-Car Display Unit Color Management Module
+ *
+ * Copyright (C) 2019 Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
+ */
+
+#ifndef __RCAR_CMM_H__
+#define __RCAR_CMM_H__
+
+#define CMM_GAMMA_LUT_SIZE		256
+
+struct platform_device;
+struct drm_color_lut;
+
+/**
+ * struct rcar_cmm_config - CMM configuration
+ *
+ * @lut:	1D-LUT configuration
+ * @lut.enable:	1D-LUT enable flag
+ * @lut.table:	1D-LUT table entries.
+ * @lut.size	1D-LUT number of entries. Max is 256.
+ */
+struct rcar_cmm_config {
+	struct {
+		bool enable;
+		struct drm_color_lut *table;
+		unsigned int size;
+	} lut;
+};
+
+int rcar_cmm_enable(struct platform_device *pdev);
+void rcar_cmm_disable(struct platform_device *pdev);
+
+int rcar_cmm_setup(struct platform_device *pdev,
+		   const struct rcar_cmm_config *config);
+
+#endif /* __RCAR_CMM_H__ */
-- 
2.21.0