Hi Tomi,
On 03-11-2025 13:35, Tomi Valkeinen wrote:
Hi,
On 28/10/2025 05:39, Swamil Jain wrote:
From: Jayesh Choudhary <[email protected]>
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/[email protected]/
[1]: https://lore.kernel.org/all/[email protected]/
Fixes: 7246e0929945 ("drm/tidss: Add OLDI bridge support")
Tested-by: Michael Walle <[email protected]>
Reviewed-by: Devarsh Thakkar <[email protected]>
Signed-off-by: Jayesh Choudhary <[email protected]>
Signed-off-by: Swamil Jain <[email protected]>
---
drivers/gpu/drm/tidss/tidss_dispc.c | 2 ++
drivers/gpu/drm/tidss/tidss_drv.h | 2 ++
drivers/gpu/drm/tidss/tidss_oldi.c | 21 +++++++++++++++++++++
3 files changed, 25 insertions(+)
diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c
b/drivers/gpu/drm/tidss/tidss_dispc.c
index 07731b02490f..0c3337a7b163 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.c
+++ b/drivers/gpu/drm/tidss/tidss_dispc.c
@@ -1315,6 +1315,8 @@ static int check_pixel_clock(struct dispc_device *dispc,
{
unsigned long round_clock;
+ if (dispc->tidss->is_ext_vp_clk[hw_videoport])
+ return 0;
Add empty line here. Also, add a short comment what this check is about.
round_clock = clk_round_rate(dispc->vp_clk[hw_videoport], clock);
/*
* To keep the check consistent with dispc_vp_set_clk_rate(), we
diff --git a/drivers/gpu/drm/tidss/tidss_drv.h
b/drivers/gpu/drm/tidss/tidss_drv.h
index 84454a4855d1..e1c1f41d8b4b 100644
--- a/drivers/gpu/drm/tidss/tidss_drv.h
+++ b/drivers/gpu/drm/tidss/tidss_drv.h
@@ -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];
diff --git a/drivers/gpu/drm/tidss/tidss_oldi.c
b/drivers/gpu/drm/tidss/tidss_oldi.c
index 7688251beba2..d1a5fdac93ff 100644
--- a/drivers/gpu/drm/tidss/tidss_oldi.c
+++ b/drivers/gpu/drm/tidss/tidss_oldi.c
@@ -309,6 +309,24 @@ 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;
Add an empty line here.
Sure, will add and respin. Thanks for reviewing.
Regards,
Swamil>
Reviewed-by: Tomi Valkeinen <[email protected]>
+ 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 +335,7 @@ 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 +449,7 @@ 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 +600,7 @@ 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);
