[RFC 7/9] drm: rcar-du: cmm: Provide 3D-CLU support

[Jacopo Mondi]

From: Kieran Bingham <kieran.bingham+renesas at ideasonboard.com>

The CMM module provides a three-dimensional cubic look up table that
converts three-color-component data into desired three color components
by use of a lookup table.

While the 1D-LUT can only control each of three color components
separately, the 3D-CLU can be used for specific color adjustment.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas at ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas at ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
---
 drivers/gpu/drm/rcar-du/rcar_cmm.c | 71 +++++++++++++++++++++++++++++-
 drivers/gpu/drm/rcar-du/rcar_cmm.h | 11 +++--
 2 files changed, 76 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_cmm.c b/drivers/gpu/drm/rcar-du/rcar_cmm.c
index df768a9afb72..defedfaf8f56 100644
--- a/drivers/gpu/drm/rcar-du/rcar_cmm.c
+++ b/drivers/gpu/drm/rcar-du/rcar_cmm.c
@@ -17,9 +17,18 @@
 
 #define CM2_LUT_CTRL		0x0000
 #define CM2_LUT_CTRL_LUT_EN	BIT(0)
+
+#define CM2_CLU_CTRL		0x0100
+#define CM2_CLU_CTRL_CLU_EN	BIT(0)
+#define CM2_CLU_CTRL_MVS	BIT(24)
+#define CM2_CLU_CTRL_AAI	BIT(28)
+
 #define CM2_LUT_TBL_BASE	0x0600
 #define CM2_LUT_TBL(__i)	(CM2_LUT_TBL_BASE + (__i) * 4)
 
+#define CM2_CLU_ADDR		0x0a00
+#define CM2_CLU_DATA		0x0a04
+
 struct rcar_cmm {
 	void __iomem *base;
 
@@ -30,6 +39,10 @@ struct rcar_cmm {
 	struct {
 		bool enabled;
 	} lut;
+
+	struct {
+		bool enabled;
+	} clu;
 };
 
 static inline int rcar_cmm_read(struct rcar_cmm *rcmm, u32 reg)
@@ -72,13 +85,63 @@ static void rcar_cmm_lut_configure(struct rcar_cmm *rcmm,
 	}
 }
 
+static void rcar_cmm_clu_program(struct rcar_cmm *rcmm,
+				 const struct drm_color_lut *table)
+{
+	unsigned int i;
+
+	/* Utilise CM2_CLU_CTRL_AAI (auto-increment). */
+	rcar_cmm_write(rcmm, CM2_CLU_ADDR, 0);
+
+	for (i = 0; i < CM2_CLU_SIZE; ++i) {
+		const struct drm_color_lut *lut = &table[i];
+
+		u32 entry = drm_color_lut_extract(lut->red, 8) << 16
+			  | drm_color_lut_extract(lut->green, 8) << 8
+			  | drm_color_lut_extract(lut->blue, 8);
+
+		rcar_cmm_write(rcmm, CM2_CLU_DATA, entry);
+	}
+}
+
+static void rcar_cmm_clu_configure(struct rcar_cmm *rcmm,
+				   const struct drm_color_lut *table)
+{
+	static const u32 clu_ctrl = CM2_CLU_CTRL_AAI | CM2_CLU_CTRL_MVS
+				  | CM2_CLU_CTRL_CLU_EN;
+	bool enable = !!table;
+
+	if (rcmm->clu.enabled != enable) {
+		/*
+		 * This is the first run of the CLU. We need to program
+		 * the CLU data before enabling the peripheral.
+		 */
+		if (enable) {
+			rcar_cmm_write(rcmm, CM2_CLU_CTRL, CM2_CLU_CTRL_AAI);
+			rcar_cmm_clu_program(rcmm, table);
+		}
+
+		rcar_cmm_write(rcmm, CM2_CLU_CTRL, enable ? clu_ctrl : 0);
+		rcmm->clu.enabled = enable;
+
+		return;
+	}
+
+	/*
+	 * CLU already enabled, but the 3D LUT has been updated; re-program
+	 * the data table with the new values.
+	 */
+	if (table)
+		rcar_cmm_clu_program(rcmm, table);
+}
+
 /*
  * 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.
+ * Configure the CMM unit with the given configuration, handling both the
+ * 1-D LUT and the 3-D CLU.
  *
  * As rcar_cmm_setup() accesses the CMM registers the unit should be powered
  * and its functional clock enabled. To guarantee this, before any call to
@@ -96,6 +159,9 @@ int rcar_cmm_setup(struct platform_device *pdev,
 	if (config->lut.update)
 		rcar_cmm_lut_configure(rcmm, config->lut.table);
 
+	if (config->clu.update)
+		rcar_cmm_clu_configure(rcmm, config->clu.table);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(rcar_cmm_setup);
@@ -140,6 +206,7 @@ void rcar_cmm_disable(struct platform_device *pdev)
 	struct rcar_cmm *rcmm = platform_get_drvdata(pdev);
 
 	rcar_cmm_lut_configure(rcmm, NULL);
+	rcar_cmm_clu_configure(rcmm, NULL);
 
 	pm_runtime_put(&pdev->dev);
 }
diff --git a/drivers/gpu/drm/rcar-du/rcar_cmm.h b/drivers/gpu/drm/rcar-du/rcar_cmm.h
index 375a3b9c3db3..277b9e4d9cc4 100644
--- a/drivers/gpu/drm/rcar-du/rcar_cmm.h
+++ b/drivers/gpu/drm/rcar-du/rcar_cmm.h
@@ -9,14 +9,15 @@
 #define __RCAR_CMM_H__
 
 #define CM2_LUT_SIZE		256
+#define CM2_CLU_SIZE		(17 * 17 * 17)
 
 struct drm_color_lut;
 struct platform_device;
 
 /**
- * struct rcar_cmm_table_config - CMM LUT configuration
- * @update: When true, update the LUT configuration.
- * @table: Table data. The LUT is enabled if non-NULL, and disabled
+ * struct rcar_cmm_table_config - CMM LUT and CLU configuration
+ * @update: When true, update the LUT or CLU configuration.
+ * @table: Table data. The LUT or CLU is enabled if non-NULL, and disabled
  *	otherwise. The value is ignored if @update is false.
  */
 struct rcar_cmm_table_config {
@@ -26,10 +27,12 @@ struct rcar_cmm_table_config {
 
 /**
  * struct rcar_cmm_config - CMM configuration
- * @lut: 1D-LUT configuration
+ * @lut: 1D LUT configuration
+ * @clu: 3D (cubic) LUT configuration
  */
 struct rcar_cmm_config {
 	struct rcar_cmm_table_config lut;
+	struct rcar_cmm_table_config clu;
 };
 
 #if IS_ENABLED(CONFIG_DRM_RCAR_CMM)
-- 
2.40.1