[PATCH v4 3/5] drm/bridge: tc358767: Drop line_pixel_subtract

[Marek Vasut <marex@xxxxxxx>]

This line_pixel_subtract is no longer needed now that the bridge can
request and obtain specific pixel clock on input to the bridge, with
clock frequency that matches the Pixel PLL frequency.

The line_pixel_subtract is now always 0, so drop it entirely.

The line_pixel_subtract was not reliable as it never worked when the
Pixel PLL and input clock were off just so that the required amount
of pixels to subtract would not be whole integer.

Reviewed-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
Signed-off-by: Marek Vasut <marex@xxxxxxx>
---
Cc: Andrzej Hajda <andrzej.hajda@xxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxxx>
Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxxx>
Cc: Jonas Karlman <jonas@xxxxxxxxx>
Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: Maxime Ripard <mripard@xxxxxxxxxx>
Cc: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
Cc: Robert Foss <rfoss@xxxxxxxxxx>
Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: kernel@xxxxxxxxxxxxxxxxxx
---
V2: No change
V3: Fix up rebase artifact
V4: - Fix another rebase mishap
    - Add RB from Alexander
---
 drivers/gpu/drm/bridge/tc358767.c | 21 +--------------------
 1 file changed, 1 insertion(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index a77be11769791..19684b8400bef 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -382,9 +382,6 @@ struct tc_data {
 
 	/* HPD pin number (0 or 1) or -ENODEV */
 	int			hpd_pin;
-
-	/* Number of pixels to subtract from a line due to pixel clock delta */
-	u32			line_pixel_subtract;
 };
 
 static inline struct tc_data *aux_to_tc(struct drm_dp_aux *a)
@@ -580,11 +577,6 @@ static int tc_pllupdate(struct tc_data *tc, unsigned int pllctrl)
 	return 0;
 }
 
-static u32 div64_round_up(u64 v, u32 d)
-{
-	return div_u64(v + d - 1, d);
-}
-
 static int tc_pxl_pll_calc(struct tc_data *tc, u32 refclk, u32 pixelclock,
 			   int *out_best_pixelclock, u32 *out_pxl_pllparam)
 {
@@ -666,11 +658,7 @@ static int tc_pxl_pll_calc(struct tc_data *tc, u32 refclk, u32 pixelclock,
 		return -EINVAL;
 	}
 
-	tc->line_pixel_subtract = tc->mode.htotal -
-		div64_round_up(tc->mode.htotal * (u64)best_pixelclock, pixelclock);
-
-	dev_dbg(tc->dev, "PLL: got %d, delta %d (subtract %d px)\n", best_pixelclock,
-		best_delta, tc->line_pixel_subtract);
+	dev_dbg(tc->dev, "PLL: got %d, delta %d\n", best_pixelclock, best_delta);
 	dev_dbg(tc->dev, "PLL: %d / %d / %d * %d / %d\n", refclk,
 		ext_div[best_pre], best_div, best_mul, ext_div[best_post]);
 
@@ -914,13 +902,6 @@ static int tc_set_common_video_mode(struct tc_data *tc,
 		upper_margin, lower_margin, vsync_len);
 	dev_dbg(tc->dev, "total: %dx%d\n", mode->htotal, mode->vtotal);
 
-	if (right_margin > tc->line_pixel_subtract) {
-		right_margin -= tc->line_pixel_subtract;
-	} else {
-		dev_err(tc->dev, "Bridge pixel clock too slow for mode\n");
-		right_margin = 0;
-	}
-
 	/*
 	 * LCD Ctl Frame Size
 	 * datasheet is not clear of vsdelay in case of DPI
-- 
2.43.0