Commit 86db652f authored by Jayesh Choudhary's avatar Jayesh Choudhary Committed by Tomi Valkeinen
Browse files

drm/tidss: Move OLDI mode validation to OLDI bridge mode_valid hook 

After integrating OLDI support[0], it is necessary to identify which VP
instances use OLDI, since the OLDI driver owns the video port clock
(as a serial clock). Clock operations on these VPs must be delegated to
the OLDI driver, not handled by the TIDSS driver. This issue also
emerged in upstream discussions when DSI-related clock management was
attempted in the TIDSS driver[1].

To address this, add an 'is_ext_vp_clk' array to the 'tidss_device'
structure, marking a VP as 'true' during 'tidss_oldi_init()' and as
'false' during 'tidss_oldi_deinit()'. TIDSS then uses 'is_ext_vp_clk'
to skip clock validation checks in 'dispc_vp_mode_valid()' for VPs
under OLDI control.

Since OLDI uses the DSS VP clock directly as a serial interface and
manages its own rate, mode validation should be implemented in the OLDI
bridge's 'mode_valid' hook. This patch adds that logic, ensuring proper
delegation and avoiding spurious clock handling in the TIDSS driver.

[0]: https://lore.kernel.org/all/20250528122544.817829-1-aradhya.bhatia@linux.dev/
[1]: https://lore.kernel.org/all/DA6TT575Z82D.3MPK8HG5GRL8U@kernel.org/



Fixes: 7246e092 ("drm/tidss: Add OLDI bridge support")
Tested-by: default avatarMichael Walle <mwalle@kernel.org>
Reviewed-by: default avatarDevarsh Thakkar <devarsht@ti.com>
Reviewed-by: default avatarTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: default avatarJayesh Choudhary <j-choudhary@ti.com>
Signed-off-by: default avatarSwamil Jain <s-jain1@ti.com>
Link: https://patch.msgid.link/20251104151422.307162-3-s-jain1@ti.com


Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patch.msgid.link/ffd5ebe03391b3c01e616c0c844a4b8ddecede36.1762513240.git.jani.nikula@intel.com
parent 527e1325

drivers/gpu/drm/tidss/tidss_dispc.c

+7 −0
Original line number Diff line number Diff line
@@ -1306,6 +1306,13 @@ static int check_pixel_clock(struct dispc_device *dispc, u32 hw_videoport, 
{

	unsigned long round_clock;



	/*

	 * For VP's with external clocking, clock operations must be

	 * delegated to respective driver, so we skip the check here.

	 */

	if (dispc->tidss->is_ext_vp_clk[hw_videoport])

		return 0;



	round_clock = clk_round_rate(dispc->vp_clk[hw_videoport], clock);

	/*

	 * To keep the check consistent with dispc_vp_set_clk_rate(), we

drivers/gpu/drm/tidss/tidss_drv.h

+2 −0
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ struct tidss_device { 


	const struct dispc_features *feat;

	struct dispc_device *dispc;

	bool is_ext_vp_clk[TIDSS_MAX_PORTS];





	unsigned int num_crtcs;

	struct drm_crtc *crtcs[TIDSS_MAX_PORTS];

drivers/gpu/drm/tidss/tidss_oldi.c

+22 −0
Original line number Diff line number Diff line
@@ -309,6 +309,25 @@ static u32 *tidss_oldi_atomic_get_input_bus_fmts(struct drm_bridge *bridge, 
	return input_fmts;

}



static enum drm_mode_status

tidss_oldi_mode_valid(struct drm_bridge *bridge,

		      const struct drm_display_info *info,

		      const struct drm_display_mode *mode)

{

	struct tidss_oldi *oldi = drm_bridge_to_tidss_oldi(bridge);

	unsigned long round_clock;



	round_clock = clk_round_rate(oldi->serial, mode->clock * 7 * 1000);

	/*

	 * To keep the check consistent with dispc_vp_set_clk_rate(),

	 * we use the same 5% check here.

	 */

	if (dispc_pclk_diff(mode->clock * 7 * 1000, round_clock) > 5)

		return -EINVAL;



	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 +336,7 @@ 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,

	.mode_valid = tidss_oldi_mode_valid,

};



static int get_oldi_mode(struct device_node *oldi_tx, int *companion_instance)
@@ -430,6 +450,7 @@ void tidss_oldi_deinit(struct tidss_device *tidss) 
	for (int i = 0; i < tidss->num_oldis; i++) {

		if (tidss->oldis[i]) {

			drm_bridge_remove(&tidss->oldis[i]->bridge);

			tidss->is_ext_vp_clk[tidss->oldis[i]->parent_vp] = false;

			tidss->oldis[i] = NULL;

		}

	}
@@ -580,6 +601,7 @@ int tidss_oldi_init(struct tidss_device *tidss) 
		oldi->bridge.timings = &default_tidss_oldi_timings;



		tidss->oldis[tidss->num_oldis++] = oldi;

		tidss->is_ext_vp_clk[oldi->parent_vp] = true;

		oldi->tidss = tidss;



		drm_bridge_add(&oldi->bridge);