[v2,03/18] drm/tidss: Adjust the pclk based on the HW capabilities

Commit Message

Tomi Valkeinen April 2, 2025, 1:30 p.m. UTC

At the moment the driver just sets the clock rate with clk_set_rate(),
and if the resulting rate is not the same as requested, prints a debug
print, but nothing else.

Add functionality to atomic_check(), in which the clk_round_rate() is
used to get the "rounded" rate, and set that to the adjusted_mode.

In practice, with the current K3 SoCs, the display PLL is capable of
producing very exact clocks, so most likely the rounded rate is the same
as the original one.

Signed-off-by: Tomi Valkeinen <[e-mail]>
---
 drivers/gpu/drm/tidss/tidss_crtc.c  | 23 +++++++++++++++++++----
 drivers/gpu/drm/tidss/tidss_dispc.c |  6 ++++++
 drivers/gpu/drm/tidss/tidss_dispc.h |  2 ++
 3 files changed, 27 insertions(+), 4 deletions(-)

Patch

diff --git a/drivers/gpu/drm/tidss/tidss_crtc.c b/drivers/gpu/drm/tidss/tidss_crtc.c
index 1604eca265ef..6c3967f70510 100644
--- a/drivers/gpu/drm/tidss/tidss_crtc.c
+++ b/drivers/gpu/drm/tidss/tidss_crtc.c
@@ -91,7 +91,7 @@  static int tidss_crtc_atomic_check(struct drm_crtc *crtc,
 	struct dispc_device *dispc = tidss->dispc;
 	struct tidss_crtc *tcrtc = to_tidss_crtc(crtc);
 	u32 hw_videoport = tcrtc->hw_videoport;
-	const struct drm_display_mode *mode;
+	struct drm_display_mode *adjusted_mode;
 	enum drm_mode_status ok;
 
 	dev_dbg(ddev->dev, "%s\n", __func__);
@@ -99,12 +99,27 @@  static int tidss_crtc_atomic_check(struct drm_crtc *crtc,
 	if (!crtc_state->enable)
 		return 0;
 
-	mode = &crtc_state->adjusted_mode;
+	adjusted_mode = &crtc_state->adjusted_mode;
 
-	ok = dispc_vp_mode_valid(dispc, hw_videoport, mode);
+	if (drm_atomic_crtc_needs_modeset(crtc_state)) {
+		long rate;
+
+		rate = dispc_vp_round_clk_rate(tidss->dispc,
+					       tcrtc->hw_videoport,
+					       adjusted_mode->clock * 1000);
+		if (rate < 0)
+			return -EINVAL;
+
+		adjusted_mode->clock = rate / 1000;
+
+		drm_mode_set_crtcinfo(adjusted_mode, 0);
+	}
+
+	ok = dispc_vp_mode_valid(dispc, hw_videoport, adjusted_mode);
 	if (ok != MODE_OK) {
 		dev_dbg(ddev->dev, "%s: bad mode: %ux%u pclk %u kHz\n",
-			__func__, mode->hdisplay, mode->vdisplay, mode->clock);
+			__func__, adjusted_mode->hdisplay,
+			adjusted_mode->vdisplay, adjusted_mode->clock);
 		return -EINVAL;
 	}
 
diff --git a/drivers/gpu/drm/tidss/tidss_dispc.c b/drivers/gpu/drm/tidss/tidss_dispc.c
index a5107f2732b1..3930fb7f03c2 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.c
+++ b/drivers/gpu/drm/tidss/tidss_dispc.c
@@ -1318,6 +1318,12 @@  unsigned int dispc_pclk_diff(unsigned long rate, unsigned long real_rate)
 	return (unsigned int)(abs(((rr - r) * 100) / r));
 }
 
+long dispc_vp_round_clk_rate(struct dispc_device *dispc, u32 hw_videoport,
+			     unsigned long rate)
+{
+	return clk_round_rate(dispc->vp_clk[hw_videoport], rate);
+}
+
 int dispc_vp_set_clk_rate(struct dispc_device *dispc, u32 hw_videoport,
 			  unsigned long rate)
 {
diff --git a/drivers/gpu/drm/tidss/tidss_dispc.h b/drivers/gpu/drm/tidss/tidss_dispc.h
index c31b477a18b0..d4c335e918fb 100644
--- a/drivers/gpu/drm/tidss/tidss_dispc.h
+++ b/drivers/gpu/drm/tidss/tidss_dispc.h
@@ -120,6 +120,8 @@  enum drm_mode_status dispc_vp_mode_valid(struct dispc_device *dispc,
 					 const struct drm_display_mode *mode);
 int dispc_vp_enable_clk(struct dispc_device *dispc, u32 hw_videoport);
 void dispc_vp_disable_clk(struct dispc_device *dispc, u32 hw_videoport);
+long dispc_vp_round_clk_rate(struct dispc_device *dispc, u32 hw_videoport,
+			     unsigned long rate);
 int dispc_vp_set_clk_rate(struct dispc_device *dispc, u32 hw_videoport,
 			  unsigned long rate);
 void dispc_vp_setup(struct dispc_device *dispc, u32 hw_videoport,