[PATCH 03/18] drm/tidss: Add mode_fixup to adjust the clock based on HW

[Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>]

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 mode_fixup(), 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 <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/tidss/tidss_crtc.c  | 22 ++++++++++++++++++++++
 drivers/gpu/drm/tidss/tidss_dispc.c |  6 ++++++
 drivers/gpu/drm/tidss/tidss_dispc.h |  2 ++
 3 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/tidss/tidss_crtc.c b/drivers/gpu/drm/tidss/tidss_crtc.c
index 1604eca265ef..b3338dac25bc 100644
--- a/drivers/gpu/drm/tidss/tidss_crtc.c
+++ b/drivers/gpu/drm/tidss/tidss_crtc.c
@@ -309,7 +309,29 @@ enum drm_mode_status tidss_crtc_mode_valid(struct drm_crtc *crtc,
 	return dispc_vp_mode_valid(tidss->dispc, tcrtc->hw_videoport, mode);
 }
 
+static bool tidss_crtc_mode_fixup(struct drm_crtc *crtc,
+				  const struct drm_display_mode *mode,
+				  struct drm_display_mode *adjusted_mode)
+{
+	struct tidss_crtc *tcrtc = to_tidss_crtc(crtc);
+	struct drm_device *ddev = crtc->dev;
+	struct tidss_device *tidss = to_tidss(ddev);
+	long rate;
+
+	rate = dispc_vp_round_clk_rate(tidss->dispc, tcrtc->hw_videoport,
+				       adjusted_mode->clock * 1000);
+	if (rate < 0)
+		return false;
+
+	adjusted_mode->clock = rate / 1000;
+
+	drm_mode_set_crtcinfo(adjusted_mode, 0);
+
+	return true;
+}
+
 static const struct drm_crtc_helper_funcs tidss_crtc_helper_funcs = {
+	.mode_fixup = tidss_crtc_mode_fixup,
 	.atomic_check = tidss_crtc_atomic_check,
 	.atomic_flush = tidss_crtc_atomic_flush,
 	.atomic_enable = tidss_crtc_atomic_enable,
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,

-- 
2.43.0