linux-kernel - [PATCH v4 3/3] drm/tidss: oldi: Add atomic

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Message-ID: <20250704094851.182131-4-j-choudhary@ti.com>
Date: Fri, 4 Jul 2025 15:18:51 +0530
From: Jayesh Choudhary <j-choudhary@...com>
To: <jyri.sarha@....fi>, <maarten.lankhorst@...ux.intel.com>,
        <mripard@...nel.org>, <tzimmermann@...e.de>,
        <dri-devel@...ts.freedesktop.org>, <devarsht@...com>,
        <tomi.valkeinen@...asonboard.com>, <mwalle@...nel.org>
CC: <airlied@...il.com>, <simona@...ll.ch>, <linux-kernel@...r.kernel.org>,
        <j-choudhary@...com>
Subject: [PATCH v4 3/3] drm/tidss: oldi: Add atomic_check hook for oldi bridge

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.

Fixes: 7246e0929945 ("drm/tidss: Add OLDI bridge support")
Reviewed-by: Devarsh Thakkar <devarsht@...com>
Signed-off-by: Jayesh Choudhary <j-choudhary@...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..486e7373531b 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_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_atomic_check,
 };
 
 static int get_oldi_mode(struct device_node *oldi_tx, int *companion_instance)
-- 
2.34.1