linux-kernel - [PATCH v5 3/3] drm/tidss: oldi: Add atomic

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Message-ID: <20250819192113.2420396-4-s-jain1@ti.com>
Date: Wed, 20 Aug 2025 00:51:13 +0530
From: Swamil Jain <s-jain1@...com>
To: <jyri.sarha@....fi>, <tomi.valkeinen@...asonboard.com>,
        <maarten.lankhorst@...ux.intel.com>, <mripard@...nel.org>,
        <tzimmermann@...e.de>, <airlied@...il.com>, <simona@...ll.ch>,
        <aradhya.bhatia@...ux.dev>
CC: <h-shenoy@...com>, <devarsht@...com>, <vigneshr@...com>, <praneeth@...com>,
        <u-kumar1@...com>, <dri-devel@...ts.freedesktop.org>,
        <linux-kernel@...r.kernel.org>, <s-jain1@...com>
Subject: [PATCH v5 3/3] drm/tidss: oldi: Add atomic_check hook for oldi bridge

From: Jayesh Choudhary <j-choudhary@...com>

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 max_successful_rate
and max_attempted_rate field for tidss in case the VP is OLDI.

Fixes: 7246e0929945 ("drm/tidss: Add OLDI bridge support")
Reviewed-by: Devarsh Thakkar <devarsht@...com>
Signed-off-by: Jayesh Choudhary <j-choudhary@...com>
Signed-off-by: Swamil Jain <s-jain1@...com>
---
 drivers/gpu/drm/tidss/tidss_oldi.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/gpu/drm/tidss/tidss_oldi.c b/drivers/gpu/drm/tidss/tidss_oldi.c
index ef01ecc17a12..2ed2d0666ccb 100644
--- a/drivers/gpu/drm/tidss/tidss_oldi.c
+++ b/drivers/gpu/drm/tidss/tidss_oldi.c
@@ -309,6 +309,30 @@ static u32 *tidss_oldi_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
 	return input_fmts;
 }
 
+static int tidss_oldi_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->max_successful_rate[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->max_successful_rate[oldi->parent_vp] = round_clock;
+		oldi->tidss->max_attempted_rate[oldi->parent_vp] = adjusted_mode->clock * 7 * 1000;
+	}
+
+	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 +341,7 @@ 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_atomic_check,
 };
 
 static int get_oldi_mode(struct device_node *oldi_tx, int *companion_instance)