[PATCH v3 3/3] drm/tidss: oldi: Add atomic_check hook for oldi bridge

[Jayesh Choudhary]

Since OLDI consumes DSS VP clock directly as serial clock, certain
checks cannot be performed in tidss driver which should be checked
in oldi driver. Add check for mode clock and set the curr_max_pclk
field for tidss in case the VP is OLDI.

Signed-off-by: Jayesh Choudhary <j-choudhary at ti.com>
---
 drivers/gpu/drm/tidss/tidss_oldi.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/gpu/drm/tidss/tidss_oldi.c b/drivers/gpu/drm/tidss/tidss_oldi.c
index 63e07c8edeaa..a1f5fb39b32c 100644
--- a/drivers/gpu/drm/tidss/tidss_oldi.c
+++ b/drivers/gpu/drm/tidss/tidss_oldi.c
@@ -309,6 +309,29 @@ static u32 *tidss_oldi_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
 	return input_fmts;
 }
 
+static int tidss_oldi_bridge_atomic_check(struct drm_bridge *bridge,
+					  struct drm_bridge_state *bridge_state,
+					  struct drm_crtc_state *crtc_state,
+					  struct drm_connector_state *conn_state)
+{
+	struct tidss_oldi *oldi = drm_bridge_to_tidss_oldi(bridge);
+	struct drm_display_mode *adjusted_mode;
+	unsigned long round_clock;
+
+	adjusted_mode = &crtc_state->adjusted_mode;
+
+	if (adjusted_mode->clock > oldi->tidss->curr_max_pclk[oldi->parent_vp]) {
+		round_clock = clk_round_rate(oldi->serial, adjusted_mode->clock * 7 * 1000);
+
+		if (dispc_pclk_diff(adjusted_mode->clock * 7 * 1000, round_clock) > 5)
+			return -EINVAL;
+
+		oldi->tidss->curr_max_pclk[oldi->parent_vp] = round_clock;
+	}
+
+	return 0;
+}
+
 static const struct drm_bridge_funcs tidss_oldi_bridge_funcs = {
 	.attach	= tidss_oldi_bridge_attach,
 	.atomic_pre_enable = tidss_oldi_atomic_pre_enable,
@@ -317,6 +340,7 @@ static const struct drm_bridge_funcs tidss_oldi_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_check = tidss_oldi_bridge_atomic_check,
 };
 
 static int get_oldi_mode(struct device_node *oldi_tx, int *companion_instance)
-- 
2.34.1