Gamma correction is optional and can be used to adjust the color
output values to match the gamut of a particular TFT LCD panel
Errata:
Gamma_R, Gamma_G and Gamma_B registers are little-endian registers
while the rest of the address-space in 2D-ACE is big-endian.
Workaround:
Split the DCU regs into "regs", "palette", "gamma" and "cursor".
Create a second regmap for gamma memory space using little endian.
Suggested-by: Stefan Agner <stefan at agner.ch>
Signed-off-by: Meng Yi <meng.yi at nxp.com>
---
Changes since V1:
-created a second regmap for gamma
-updated the DCU DT binding
-removed Kconfig for gamma and enable gamma when valid data filled.
---
.../devicetree/bindings/display/fsl,dcu.txt | 15 +++++++++-
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c | 32 ++++++++++++++++++++
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 35 +++++++++++++++++++++-
drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h | 7 +++++
4 files changed, 87 insertions(+), 2 deletions(-)
diff --git a/Documentation/devicetree/bindings/display/fsl,dcu.txt
b/Documentation/devicetree/bindings/display/fsl,dcu.txt
index 63ec2a6..e3cf2de 100644
--- a/Documentation/devicetree/bindings/display/fsl,dcu.txt
+++ b/Documentation/devicetree/bindings/display/fsl,dcu.txt
@@ -6,6 +6,15 @@ Required properties:
* "fsl,vf610-dcu".
- reg: Address and length of the register set for dcu.
+ Parameter Address Range
+
+ Register address space 0x0000 â 0x1FFF
+ Palette/Tile address space 0x2000 â 0x3FFF
+ Gamma_R address space 0x4000 â 0x43FF
+ Gamma_G address space 0x4400 â 0x47FF
+ Gamma_B address space 0x4800 â 0x4BFF
+ Cursor address space 0x4C00 â 0x4FFF
+
- clocks: Handle to "dcu" and "pix" clock (in the order below)
This can be the same clock (e.g. LS1021a)
See ../clocks/clock-bindings.txt for details.
@@ -20,7 +29,11 @@ Optional properties:
Examples:
dcu: dcu at 2ce0000 {
compatible = "fsl,ls1021a-dcu";
- reg = <0x0 0x2ce0000 0x0 0x10000>;
+ reg = <0x0 0x2ce0000 0x0 0x2000>,
+ <0x0 0x2ce2000 0x0 0x2000>,
+ <0x0 0x2ce4000 0x0 0xc00>,
+ <0x0 0x2ce4c00 0x0 0x400>;
+ reg-names = "regs", "palette", "gamma", "cursor";
clocks = <&platform_clk 0>, <&platform_clk 0>;
clock-names = "dcu", "pix";
big-endian;
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
index 3371635..4ff969b 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
@@ -22,6 +22,30 @@
#include "fsl_dcu_drm_drv.h"
#include "fsl_dcu_drm_plane.h"
+static void fsl_crtc_gamma_set(struct drm_crtc *crtc, struct drm_color_lut
*lut,
+ uint32_t size)
+{
+ struct fsl_dcu_drm_device *fsl_dev = crtc->dev->dev_private;
+ unsigned int i;
+
+ if (crtc->state->gamma_lut->data) {
+ for (i = 0; i < size; i++) {
+ regmap_write(fsl_dev->regmap_gamma, FSL_GAMMA_R + 4 * i,
+ lut[i].red);
+ regmap_write(fsl_dev->regmap_gamma, FSL_GAMMA_G + 4 * i,
+ lut[i].green);
+ regmap_write(fsl_dev->regmap_gamma, FSL_GAMMA_B + 4 * i,
+ lut[i].blue);
+ }
+
+ regmap_update_bits(fsl_dev->regmap, DCU_DCU_MODE,
+ DCU_MODE_EN_GAMMA_MASK,
+ DCU_MODE_GAMMA_ENABLE);
+ } else
+ regmap_update_bits(fsl_dev->regmap, DCU_DCU_MODE,
+ DCU_MODE_EN_GAMMA_MASK, 0);
+}
+
static void fsl_dcu_drm_crtc_atomic_flush(struct drm_crtc *crtc,
struct drm_crtc_state *old_crtc_state)
{
@@ -37,6 +61,10 @@ static void fsl_dcu_drm_crtc_atomic_flush(struct drm_crtc
*crtc,
drm_crtc_send_vblank_event(crtc, event);
spin_unlock_irq(&crtc->dev->event_lock);
}
+
+ if (crtc->state->color_mgmt_changed && crtc->state->gamma_lut)
+ fsl_crtc_gamma_set(crtc, (struct drm_color_lut *)
+ crtc->state->gamma_lut->data, 256);
}
static void fsl_dcu_drm_disable_crtc(struct drm_crtc *crtc)
@@ -135,6 +163,7 @@ static const struct drm_crtc_funcs fsl_dcu_drm_crtc_funcs =
{
.page_flip = drm_atomic_helper_page_flip,
.reset = drm_atomic_helper_crtc_reset,
.set_config = drm_atomic_helper_set_config,
+ .gamma_set = drm_atomic_helper_legacy_gamma_set,
};
int fsl_dcu_drm_crtc_create(struct fsl_dcu_drm_device *fsl_dev)
@@ -158,5 +187,8 @@ int fsl_dcu_drm_crtc_create(struct fsl_dcu_drm_device
*fsl_dev)
drm_crtc_helper_add(crtc, &fsl_dcu_drm_crtc_helper_funcs);
+ drm_crtc_enable_color_mgmt(crtc, 0, false, 256);
+ drm_mode_crtc_set_gamma_size(crtc, 256);
+
return 0;
}
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index 092aaec..e662890 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -48,6 +48,20 @@ static const struct regmap_config fsl_dcu_regmap_config = {
.volatile_reg = fsl_dcu_drm_is_volatile_reg,
};
+/*
+ * force using little endian here since ls1021a's gamma regs are little
+ * endian while the other regs are big endian, and all vf610s's regs
+ * are little endian
+ */
+static const struct regmap_config fsl_dcu_regmap_gamma_config = {
+ .reg_bits = 32,
+ .reg_stride = 4,
+ .val_bits = 32,
+ .val_format_endian = REGMAP_ENDIAN_LITTLE,
+
+ .volatile_reg = fsl_dcu_drm_is_volatile_reg,
+};
+
static int fsl_dcu_drm_irq_init(struct drm_device *dev)
{
struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
@@ -327,7 +341,7 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
struct drm_device *drm;
struct device *dev = &pdev->dev;
struct resource *res;
- void __iomem *base;
+ void __iomem *base, *base_gamma;
struct drm_driver *driver = &fsl_dcu_drm_driver;
struct clk *pix_clk_in;
char pix_clk_name[32];
@@ -370,6 +384,25 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
return PTR_ERR(fsl_dev->regmap);
}
+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "gamma");
+ if (!res) {
+ dev_err(dev, "could not get gamma memory resource\n");
+ return -ENODEV;
+ }
+
+ base_gamma = devm_ioremap_resource(dev, res);
+ if (IS_ERR(base_gamma)) {
+ ret = PTR_ERR(base_gamma);
+ return ret;
+ }
+
+ fsl_dev->regmap_gamma = devm_regmap_init_mmio(dev, base_gamma,
+ &fsl_dcu_regmap_gamma_config);
+ if (IS_ERR(fsl_dev->regmap_gamma)) {
+ dev_err(dev, "regmap_gamma init failed\n");
+ return PTR_ERR(fsl_dev->regmap_gamma);
+ }
+
fsl_dev->clk = devm_clk_get(dev, "dcu");
if (IS_ERR(fsl_dev->clk)) {
dev_err(dev, "failed to get dcu clock\n");
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
index 3b371fe7..2610b6c 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.h
@@ -25,6 +25,8 @@
#define DCU_MODE_NORMAL 1
#define DCU_MODE_TEST 2
#define DCU_MODE_COLORBAR 3
+#define DCU_MODE_EN_GAMMA_MASK 0x04
+#define DCU_MODE_GAMMA_ENABLE BIT(2)
#define DCU_BGND 0x0014
#define DCU_BGND_R(x) ((x) << 16)
@@ -165,6 +167,10 @@
#define VF610_LAYER_REG_NUM 9
#define LS1021A_LAYER_REG_NUM 10
+#define FSL_GAMMA_R 0x000
+#define FSL_GAMMA_G 0x400
+#define FSL_GAMMA_B 0x800
+
struct clk;
struct device;
struct drm_device;
@@ -182,6 +188,7 @@ struct fsl_dcu_drm_device {
struct device *dev;
struct device_node *np;
struct regmap *regmap;
+ struct regmap *regmap_gamma;
int irq;
struct clk *clk;
struct clk *pix_clk;
--
2.1.0.27.g96db324
