drm: provide a helper for the encoder possible_crtcs mask

The encoder possible_crtcs mask identifies which CRTCs can be bound to
a particular encoder.  Each bit from bit 0 defines an index in the list
of CRTCs held in the DRM mode_config crtc_list.  Rather than having
drivers trying to track the position of their CRTCs in the list, expose
the code which already exists for calculating the appropriate mask bit
for a CRTC.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
[treding@nvidia.com: add drm_crtc_index(), move to core]
Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 1 insertions, 17 deletions

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index 01361aba033b..940c678cf012 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -334,23 +334,7 @@ EXPORT_SYMBOL(drm_helper_disable_unused_functions);
 static bool drm_encoder_crtc_ok(struct drm_encoder *encoder,
                                 struct drm_crtc *crtc)
 {
-        struct drm_device *dev;
-        struct drm_crtc *tmp;
-        int crtc_mask = 1;
-
-        WARN(!crtc, "checking null crtc?\n");
-
-        dev = crtc->dev;
-
-        list_for_each_entry(tmp, &dev->mode_config.crtc_list, head) {
-                if (tmp == crtc)
-                        break;
-                crtc_mask <<= 1;
-        }
-
-        if (encoder->possible_crtcs & crtc_mask)
-                return true;
-        return false;
+        return !!(encoder->possible_crtcs & drm_crtc_mask(crtc));
 }
 
 /*