From: Peter Rosin <peda@axentia.se>
To: linux-kernel@vger.kernel.org
Cc: Peter Rosin <peda@axentia.se>,
        Boris Brezillon <boris.brezillon@free-electrons.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel.vetter@intel.com>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Sean Paul <seanpaul@chromium.org>, dri-devel@lists.freedesktop.org
Subject: [RFC PATCH 3/3] atmel-hlcdc: add clut support for legacy fbdev
Date: Fri, 16 Jun 2017 11:12:27 +0200
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The clut is also synchronized with the drm gamma_lut state.

Signed-off-by: Peter Rosin <peda@axentia.se>
---
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c | 49 ++++++++++++++++++++++++++
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c   | 12 +++++--
 drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h   |  4 +++
 3 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
index 75871b5..54ecf56 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c
@@ -158,6 +158,54 @@ atmel_hlcdc_crtc_load_lut(struct drm_crtc *c)
 	}
 }
 
+void atmel_hlcdc_gamma_set(struct drm_crtc *c,
+			   u16 r, u16 g, u16 b, int idx)
+{
+	struct atmel_hlcdc_crtc *crtc = drm_crtc_to_atmel_hlcdc_crtc(c);
+	struct drm_crtc_state *state = c->state;
+	struct drm_color_lut *lut;
+
+	if (idx < 0 || idx > 255)
+		return;
+
+	if (state->gamma_lut) {
+		lut = (struct drm_color_lut *)state->gamma_lut->data;
+
+		lut[idx].red = r;
+		lut[idx].green = g;
+		lut[idx].blue = b;
+	}
+
+	crtc->clut[idx] = ((r << 8) & 0xff0000) | (g & 0xff00) | (b >> 8);
+}
+
+void atmel_hlcdc_gamma_get(struct drm_crtc *c,
+			   u16 *r, u16 *g, u16 *b, int idx)
+{
+	struct atmel_hlcdc_crtc *crtc = drm_crtc_to_atmel_hlcdc_crtc(c);
+	struct drm_crtc_state *state = c->state;
+	struct drm_color_lut *lut;
+
+	if (idx < 0 || idx > 255)
+		return;
+
+	if (state->gamma_lut) {
+		lut = (struct drm_color_lut *)state->gamma_lut->data;
+
+		*r = lut[idx].red;
+		*g = lut[idx].green;
+		*b = lut[idx].blue;
+		return;
+	}
+
+	*r = (crtc->clut[idx] >> 8) & 0xff00;
+	*g = crtc->clut[idx] & 0xff00;
+	*b = (crtc->clut[idx] << 8) & 0xff00;
+	*r |= *r >> 8;
+	*g |= *g >> 8;
+	*b |= *b >> 8;
+}
+
 static void
 atmel_hlcdc_crtc_flush_lut(struct drm_crtc *c)
 {
@@ -363,6 +411,7 @@ static const struct drm_crtc_helper_funcs lcdc_crtc_helper_funcs = {
 	.mode_set = drm_helper_crtc_mode_set,
 	.mode_set_nofb = atmel_hlcdc_crtc_mode_set_nofb,
 	.mode_set_base = drm_helper_crtc_mode_set_base,
+	.load_lut = atmel_hlcdc_crtc_load_lut,
 	.disable = atmel_hlcdc_crtc_disable,
 	.enable = atmel_hlcdc_crtc_enable,
 	.atomic_check = atmel_hlcdc_crtc_atomic_check,
diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
index 4f6ef07..9a09c73 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c
@@ -601,6 +601,12 @@ static int atmel_hlcdc_dc_modeset_init(struct drm_device *dev)
 	return 0;
 }
 
+static const struct drm_fb_helper_funcs atmel_hlcdc_fb_cma_helper_funcs = {
+	.gamma_set	= atmel_hlcdc_gamma_set,
+	.gamma_get	= atmel_hlcdc_gamma_get,
+	.fb_probe	= drm_fbdev_cma_create,
+};
+
 static int atmel_hlcdc_dc_load(struct drm_device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev->dev);
@@ -664,8 +670,10 @@ static int atmel_hlcdc_dc_load(struct drm_device *dev)
 
 	platform_set_drvdata(pdev, dev);
 
-	dc->fbdev = drm_fbdev_cma_init(dev, 24,
-			dev->mode_config.num_connector);
+	dc->fbdev = drm_fbdev_cma_init_with_funcs2(dev, 24,
+			dev->mode_config.num_connector,
+			NULL,
+			&atmel_hlcdc_fb_cma_helper_funcs);
 	if (IS_ERR(dc->fbdev))
 		dc->fbdev = NULL;
 
diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h
index 709f7b9..1b13224 100644
--- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h
+++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h
@@ -32,6 +32,7 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
+#include <drm/drm_fb_helper.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_panel.h>
@@ -448,6 +449,9 @@ void atmel_hlcdc_plane_irq(struct atmel_hlcdc_plane *plane);
 int atmel_hlcdc_plane_prepare_disc_area(struct drm_crtc_state *c_state);
 int atmel_hlcdc_plane_prepare_ahb_routing(struct drm_crtc_state *c_state);
 
+void atmel_hlcdc_gamma_set(struct drm_crtc *c, u16 r, u16 g, u16 b, int idx);
+void atmel_hlcdc_gamma_get(struct drm_crtc *c, u16 *r, u16 *g, u16 *b, int idx);
+
 void atmel_hlcdc_crtc_irq(struct drm_crtc *c);
 
 int atmel_hlcdc_crtc_create(struct drm_device *dev);
-- 
2.1.4