[PATCH v3 1/4] drm: Create mipi_dsi_dual macro

[Brigham Campbell]

Create mipi_dsi_dual macro for panels which are driven by two parallel
serial interfaces. This allows for the reduction of code duplication in
drivers for these panels.

Signed-off-by: Brigham Campbell <me at brighamcampbell.com>
---

In case it's not obvious, the indirection between mipi_dsi_dual and
_mipi_dsi_dual is meant to allow for the expansion of _func in the case
that _func is also a macro.

 include/drm/drm_mipi_dsi.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 369b0d8830c3..32da8861f9de 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -431,6 +431,30 @@ void mipi_dsi_dcs_set_tear_off_multi(struct mipi_dsi_multi_context *ctx);
 		mipi_dsi_dcs_write_buffer_multi(ctx, d, ARRAY_SIZE(d)); \
 	} while (0)
 
+/**
+ * mipi_dsi_dual - send the same MIPI DSI command to two interfaces
+ *
+ * This macro will send the specified MIPI DSI command twice, once per each of
+ * the two interfaces supplied. This is useful for reducing duplication of code
+ * in panel drivers which use two parallel serial interfaces.
+ *
+ * @_func: MIPI DSI function or macro to pass context and arguments into
+ * @_dsi1: First DSI interface to act as recipient of the MIPI DSI command
+ * @_dsi2: Second DSI interface to act as recipient of the MIPI DSI command
+ * @_ctx: Context for multiple DSI transactions
+ * @...: Arguments to pass to MIPI DSI function or macro
+ */
+#define mipi_dsi_dual(_func, _dsi1, _dsi2, _ctx, ...) 		 \
+	_mipi_dsi_dual(_func, _dsi1, _dsi2, _ctx, ##__VA_ARGS__)
+
+#define _mipi_dsi_dual(_func, _dsi1, _dsi2, _ctx, ...) \
+	do {					       \
+		(_ctx)->dsi = (_dsi1);		       \
+		_func((_ctx), ##__VA_ARGS__);	       \
+		(_ctx)->dsi = (_dsi2);		       \
+		_func((_ctx), ##__VA_ARGS__);	       \
+	} while (0)
+
 /**
  * struct mipi_dsi_driver - DSI driver
  * @driver: device driver model driver
-- 
2.49.0