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Subject[PATCH v6 3/8] drm: rcar-du: Add support for CMM
Date
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 features will be
implemented on top of this initial one.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
---
drivers/gpu/drm/rcar-du/Kconfig | 7 +
drivers/gpu/drm/rcar-du/Makefile | 1 +
drivers/gpu/drm/rcar-du/rcar_cmm.c | 212 +++++++++++++++++++++++++++++
drivers/gpu/drm/rcar-du/rcar_cmm.h | 58 ++++++++
4 files changed, 278 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..4170626208cf
--- /dev/null
+++ b/drivers/gpu/drm/rcar-du/rcar_cmm.c
@@ -0,0 +1,212 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * rcar_cmm.c -- R-Car Display Unit Color Management Module
+ *
+ * Copyright (C) 2019 Jacopo Mondi <jacopo+renesas@jmondi.org>
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#include <drm/drm_color_mgmt.h>
+
+#include "rcar_cmm.h"
+
+#define CM2_LUT_CTRL 0x0000
+#define CM2_LUT_CTRL_LUT_EN BIT(0)
+#define CM2_LUT_TBL_BASE 0x0600
+#define CM2_LUT_TBL(__i) (CM2_LUT_TBL_BASE + (__i) * 4)
+
+struct rcar_cmm {
+ void __iomem *base;
+
+ /*
+ * @lut: 1D-LUT state
+ * @lut.enabled: 1D-LUT enabled flag
+ */
+ struct {
+ bool enabled;
+ } 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);
+}
+
+/*
+ * rcar_cmm_lut_write() - Scale the DRM LUT table entries to hardware precision
+ * and write to the CMM registers
+ * @rcmm: Pointer to the CMM device
+ * @drm_lut: Pointer to the DRM LUT table
+ */
+static void rcar_cmm_lut_write(struct rcar_cmm *rcmm,
+ const struct drm_color_lut *drm_lut)
+{
+ unsigned int i;
+
+ for (i = 0; i < CM2_LUT_SIZE; ++i) {
+ u32 entry = drm_color_lut_extract(drm_lut[i].red, 8) << 16
+ | drm_color_lut_extract(drm_lut[i].green, 8) << 8
+ | drm_color_lut_extract(drm_lut[i].blue, 8);
+
+ rcar_cmm_write(rcmm, CM2_LUT_TBL(i), entry);
+ }
+}
+
+/*
+ * rcar_cmm_setup() - Configure the CMM unit
+ * @pdev: The platform device associated with the CMM instance
+ * @config: The CMM unit configuration
+ *
+ * Configure the CMM unit with the given configuration. Currently enabling,
+ * disabling and programming of the 1-D LUT unit is supported.
+ *
+ * TODO: Add support for LUT double buffer operations to avoid updating the
+ * LUT table entries while a frame is being displayed.
+ */
+int rcar_cmm_setup(struct platform_device *pdev,
+ const struct rcar_cmm_config *config)
+{
+ struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
+
+ /* Disable LUT if no table is provided. */
+ if (!config->lut.table) {
+ if (rcmm->lut.enabled) {
+ rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0);
+ rcmm->lut.enabled = false;
+ }
+
+ return 0;
+ }
+
+ /* Enable LUT and program the new gamma table values. */
+ if (!rcmm->lut.enabled) {
+ rcar_cmm_write(rcmm, CM2_LUT_CTRL, CM2_LUT_CTRL_LUT_EN);
+ rcmm->lut.enabled = true;
+ }
+
+ rcar_cmm_lut_write(rcmm, config->lut.table);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(rcar_cmm_setup);
+
+/*
+ * rcar_cmm_enable() - Enable the CMM unit
+ * @pdev: The platform device associated with the CMM instance
+ *
+ * When the output of the corresponding DU channel is routed to the CMM unit,
+ * the unit shall be enabled before the DU channel is started, and remain
+ * enabled until the channel is stopped. The CMM unit shall be disabled with
+ * rcar_cmm_disable().
+ *
+ * Calls to rcar_cmm_enable() and rcar_cmm_disable() are not reference-counted.
+ * It is an error to attempt to enable an already enabled CMM unit, or to
+ * attempt to disable a disabled unit.
+ */
+int rcar_cmm_enable(struct platform_device *pdev)
+{
+ int ret;
+
+ ret = pm_runtime_get_sync(&pdev->dev);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(rcar_cmm_enable);
+
+/*
+ * rcar_cmm_disable() - Disable the CMM unit
+ * @pdev: The platform device associated with the CMM instance
+ *
+ * See rcar_cmm_enable() for usage information.
+ *
+ * Disabling the CMM unit disable all the internal processing blocks. The CMM
+ * state shall thus be restored with rcar_cmm_setup() when re-enabling the CMM
+ * unit after the next rcar_cmm_enable() call.
+ */
+void rcar_cmm_disable(struct platform_device *pdev)
+{
+ struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
+
+ rcar_cmm_write(rcmm, CM2_LUT_CTRL, 0);
+ rcmm->lut.enabled = false;
+
+ pm_runtime_put(&pdev->dev);
+}
+EXPORT_SYMBOL_GPL(rcar_cmm_disable);
+
+/*
+ * rcar_cmm_init() - Initialize the CMM unit
+ * @pdev: The platform device associated with the CMM instance
+ *
+ * Return: 0 on success, -EPROBE_DEFER if the CMM is not available yet,
+ * -ENODEV if the DRM_RCAR_CMM config option is disabled
+ */
+int rcar_cmm_init(struct platform_device *pdev)
+{
+ struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
+
+ if (!rcmm)
+ return -EPROBE_DEFER;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(rcar_cmm_init);
+
+static int rcar_cmm_probe(struct platform_device *pdev)
+{
+ struct rcar_cmm *rcmm;
+
+ rcmm = devm_kzalloc(&pdev->dev, sizeof(*rcmm), GFP_KERNEL);
+ if (!rcmm)
+ return -ENOMEM;
+ platform_set_drvdata(pdev, rcmm);
+
+ rcmm->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(rcmm->base))
+ return PTR_ERR(rcmm->base);
+
+ pm_runtime_enable(&pdev->dev);
+
+ return 0;
+}
+
+static int rcar_cmm_remove(struct platform_device *pdev)
+{
+ pm_runtime_disable(&pdev->dev);
+
+ 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,
+ .remove = rcar_cmm_remove,
+ .driver = {
+ .name = "rcar-cmm",
+ .of_match_table = rcar_cmm_of_table,
+ },
+};
+
+module_platform_driver(rcar_cmm_platform_driver);
+
+MODULE_AUTHOR("Jacopo Mondi <jacopo+renesas@jmondi.org>");
+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..b5f7ec6db04a
--- /dev/null
+++ b/drivers/gpu/drm/rcar-du/rcar_cmm.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * rcar_cmm.h -- R-Car Display Unit Color Management Module
+ *
+ * Copyright (C) 2019 Jacopo Mondi <jacopo+renesas@jmondi.org>
+ */
+
+#ifndef __RCAR_CMM_H__
+#define __RCAR_CMM_H__
+
+#define CM2_LUT_SIZE 256
+
+struct drm_color_lut;
+struct platform_device;
+
+/**
+ * struct rcar_cmm_config - CMM configuration
+ *
+ * @lut: 1D-LUT configuration
+ * @lut.table: 1D-LUT table entries. Disable LUT operations when NULL
+ */
+struct rcar_cmm_config {
+ struct {
+ struct drm_color_lut *table;
+ } lut;
+};
+
+#if IS_ENABLED(CONFIG_DRM_RCAR_CMM)
+int rcar_cmm_init(struct platform_device *pdev);
+
+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);
+#else
+static inline int rcar_cmm_init(struct platform_device *pdev)
+{
+ return -ENODEV;
+}
+
+static inline int rcar_cmm_enable(struct platform_device *pdev)
+{
+ return 0;
+}
+
+static inline void rcar_cmm_disable(struct platform_device *pdev)
+{
+}
+
+static inline int rcar_cmm_setup(struct platform_device *pdev,
+ const struct rcar_cmm_config *config)
+{
+ return 0;
+}
+#endif /* IS_ENABLED(CONFIG_DRM_RCAR_CMM) */
+
+#endif /* __RCAR_CMM_H__ */
--
2.23.0
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