Add EDID support to sysfb connector helpers. Read the EDID property
from the OF node in ofdrm. Without EDID, this does nothing.
Some systems with OF display, such as 32-bit PPC Macintoshs, provide
the system display's EDID data as node property in their DT. Exporting
this information allows compositors to implement correct DPI and
meaningful color management.
v3:
- avoid parser error by clearing EDID extension field
v2:
- return errno codes on errors (Jani)
- simplify EDID read logic (Jani)
Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>
Reviewed-by: Javier Martinez Canillas <javi...@redhat.com>
---
drivers/gpu/drm/sysfb/drm_sysfb_helper.c | 34 ++++++++++++++++++++++++
drivers/gpu/drm/sysfb/drm_sysfb_helper.h | 2 ++
drivers/gpu/drm/sysfb/ofdrm.c | 20 ++++++++++++++
3 files changed, 56 insertions(+)
diff --git a/drivers/gpu/drm/sysfb/drm_sysfb_helper.c
b/drivers/gpu/drm/sysfb/drm_sysfb_helper.c
index b48e06b253051..262490a717924 100644
--- a/drivers/gpu/drm/sysfb/drm_sysfb_helper.c
+++ b/drivers/gpu/drm/sysfb/drm_sysfb_helper.c
@@ -9,6 +9,7 @@
#include <drm/drm_atomic_state_helper.h>
#include <drm/drm_damage_helper.h>
#include <drm/drm_drv.h>
+#include <drm/drm_edid.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_gem_atomic_helper.h>
@@ -281,10 +282,43 @@ EXPORT_SYMBOL(drm_sysfb_crtc_atomic_destroy_state);
* Connector
*/
+static int drm_sysfb_get_edid_block(void *data, u8 *buf, unsigned int block,
size_t len)
+{
+ struct drm_sysfb_device *sysfb = data;
+ const u8 *edid = sysfb->edid;
+ size_t off = block * EDID_LENGTH;
+ size_t end = off + len;
+
+ if (!edid)
+ return -EINVAL;
+ if (end > EDID_LENGTH)
+ return -EINVAL;
+ memcpy(buf, &edid[off], len);
+
+ /*
+ * We don't have EDID extensions available and reporting them
+ * will upset DRM helpers. Thus clear the extension field and
+ * update the checksum. Adding the extension flag to the checksum
+ * does this.
+ */
+ buf[127] += buf[126];
+ buf[126] = 0;
+
+ return 0;
+}
+
int drm_sysfb_connector_helper_get_modes(struct drm_connector *connector)
{
struct drm_sysfb_device *sysfb = to_drm_sysfb_device(connector->dev);
+ const struct drm_edid *drm_edid;
+
+ if (sysfb->edid) {
+ drm_edid = drm_edid_read_custom(connector,
drm_sysfb_get_edid_block, sysfb);
+ drm_edid_connector_update(connector, drm_edid);
+ drm_edid_free(drm_edid);
+ }
+ /* Return the fixed mode even with EDID */
return drm_connector_helper_get_modes_fixed(connector, &sysfb->fb_mode);
}
EXPORT_SYMBOL(drm_sysfb_connector_helper_get_modes);
diff --git a/drivers/gpu/drm/sysfb/drm_sysfb_helper.h
b/drivers/gpu/drm/sysfb/drm_sysfb_helper.h
index 45e396bf74b73..3684bd0ef0853 100644
--- a/drivers/gpu/drm/sysfb/drm_sysfb_helper.h
+++ b/drivers/gpu/drm/sysfb/drm_sysfb_helper.h
@@ -24,6 +24,8 @@ struct drm_display_mode drm_sysfb_mode(unsigned int width,
struct drm_sysfb_device {
struct drm_device dev;
+ const u8 *edid; /* can be NULL */
+
/* hardware settings */
struct drm_display_mode fb_mode;
const struct drm_format_info *fb_format;
diff --git a/drivers/gpu/drm/sysfb/ofdrm.c b/drivers/gpu/drm/sysfb/ofdrm.c
index 71e661ba93299..86c1a0c80ceb3 100644
--- a/drivers/gpu/drm/sysfb/ofdrm.c
+++ b/drivers/gpu/drm/sysfb/ofdrm.c
@@ -12,6 +12,7 @@
#include <drm/drm_damage_helper.h>
#include <drm/drm_device.h>
#include <drm/drm_drv.h>
+#include <drm/drm_edid.h>
#include <drm/drm_fbdev_shmem.h>
#include <drm/drm_format_helper.h>
#include <drm/drm_framebuffer.h>
@@ -227,6 +228,16 @@ static u64 display_get_address_of(struct drm_device *dev,
struct device_node *of
return address;
}
+static const u8 *display_get_edid_of(struct drm_device *dev, struct
device_node *of_node,
+ u8 buf[EDID_LENGTH])
+{
+ int ret = of_property_read_u8_array(of_node, "EDID", buf, EDID_LENGTH);
+
+ if (ret)
+ return NULL;
+ return buf;
+}
+
static bool is_avivo(u32 vendor, u32 device)
{
/* This will match most R5xx */
@@ -298,6 +309,8 @@ struct ofdrm_device {
/* colormap */
void __iomem *cmap_base;
+ u8 edid[EDID_LENGTH];
+
/* modesetting */
u32 formats[DRM_SYSFB_PLANE_NFORMATS(1)];
struct drm_plane primary_plane;
@@ -840,6 +853,7 @@ static struct ofdrm_device *ofdrm_device_create(struct
drm_driver *drv,
int width, height, depth, linebytes;
const struct drm_format_info *format;
u64 address;
+ const u8 *edid;
resource_size_t fb_size, fb_base, fb_pgbase, fb_pgsize;
struct resource *res, *mem;
void __iomem *screen_base;
@@ -989,6 +1003,9 @@ static struct ofdrm_device *ofdrm_device_create(struct
drm_driver *drv,
}
}
+ /* EDID is optional */
+ edid = display_get_edid_of(dev, of_node, odev->edid);
+
/*
* Firmware framebuffer
*/
@@ -999,6 +1016,7 @@ static struct ofdrm_device *ofdrm_device_create(struct
drm_driver *drv,
sysfb->fb_pitch = linebytes;
if (odev->cmap_base)
sysfb->fb_gamma_lut_size = OFDRM_GAMMA_LUT_SIZE;
+ sysfb->edid = edid;
drm_dbg(dev, "display mode={" DRM_MODE_FMT "}\n",
DRM_MODE_ARG(&sysfb->fb_mode));
drm_dbg(dev, "framebuffer format=%p4cc, size=%dx%d, linebytes=%d
byte\n",
@@ -1072,6 +1090,8 @@ static struct ofdrm_device *ofdrm_device_create(struct
drm_driver *drv,
drm_connector_set_panel_orientation_with_quirk(connector,
DRM_MODE_PANEL_ORIENTATION_UNKNOWN,
width, height);
+ if (edid)
+ drm_connector_attach_edid_property(connector);
ret = drm_connector_attach_encoder(connector, encoder);
if (ret)
--
2.49.0
