[PATCH v8 09/14] drm: bridge: samsung-dsim: Add atomic_get_input_bus_fmts

[Jagan Teki <jagan@amarulasolutions.com>]

Finding the right input bus format throughout the pipeline is hard
so add atomic_get_input_bus_fmts callback and initialize with the
proper input format from list of supported output formats.

This format can be used in pipeline for negotiating bus format between
the DSI-end of this bridge and the other component closer to pipeline
components.

List of Pixel formats are taken from,
AN13573 i.MX 8/RT MIPI DSI/CSI-2, Rev. 0, 21 March 2022
3.7.4 Pixel formats
Table 14. DSI pixel packing formats

v8:
* added pixel formats supported by NXP AN13573 i.MX 8/RT MIPI DSI/CSI-2

v7, v6, v5, v4:
* none

v3:
* include media-bus-format.h

v2:
* none

v1:
* new patch

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
 drivers/gpu/drm/bridge/samsung-dsim.c | 53 +++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index 0fe153b29e4f..33e5ae9c865f 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -15,6 +15,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/irq.h>
+#include <linux/media-bus-format.h>
 #include <linux/of_device.h>
 #include <linux/phy/phy.h>
 
@@ -1321,6 +1322,57 @@ static void samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
 	pm_runtime_put_sync(dsi->dev);
 }
 
+/*
+ * This pixel output formats list referenced from,
+ * AN13573 i.MX 8/RT MIPI DSI/CSI-2, Rev. 0, 21 March 2022
+ * 3.7.4 Pixel formats
+ * Table 14. DSI pixel packing formats
+ */
+static const u32 samsung_dsim_pixel_output_fmts[] = {
+	MEDIA_BUS_FMT_UYVY8_1X16,
+	MEDIA_BUS_FMT_RGB101010_1X30,
+	MEDIA_BUS_FMT_RGB121212_1X36,
+	MEDIA_BUS_FMT_RGB565_1X16,
+	MEDIA_BUS_FMT_RGB666_1X18,
+	MEDIA_BUS_FMT_RGB888_1X24,
+};
+
+static bool samsung_dsim_pixel_output_fmt_supported(u32 fmt)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(samsung_dsim_pixel_output_fmts); i++) {
+		if (samsung_dsim_pixel_output_fmts[i] == fmt)
+			return true;
+	}
+
+	return false;
+}
+
+static u32 *
+samsung_dsim_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
+				       struct drm_bridge_state *bridge_state,
+				       struct drm_crtc_state *crtc_state,
+				       struct drm_connector_state *conn_state,
+				       u32 output_fmt,
+				       unsigned int *num_input_fmts)
+{
+	u32 *input_fmts;
+
+	if (!samsung_dsim_pixel_output_fmt_supported(output_fmt))
+		return NULL;
+
+	*num_input_fmts = 1;
+
+	input_fmts = kmalloc(sizeof(*input_fmts), GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	input_fmts[0] = output_fmt;
+
+	return input_fmts;
+}
+
 static int samsung_dsim_atomic_check(struct drm_bridge *bridge,
 				     struct drm_bridge_state *bridge_state,
 				     struct drm_crtc_state *crtc_state,
@@ -1385,6 +1437,7 @@ static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
 	.atomic_duplicate_state		= drm_atomic_helper_bridge_duplicate_state,
 	.atomic_destroy_state		= drm_atomic_helper_bridge_destroy_state,
 	.atomic_reset			= drm_atomic_helper_bridge_reset,
+	.atomic_get_input_bus_fmts	= samsung_dsim_atomic_get_input_bus_fmts,
 	.atomic_check			= samsung_dsim_atomic_check,
 	.atomic_pre_enable		= samsung_dsim_atomic_pre_enable,
 	.atomic_enable			= samsung_dsim_atomic_enable,
-- 
2.25.1