drm/mediatek: mtk_dpi: Move pixel clock setting flow to function

In preparation for adding support for the DPI IP found in MT8195
and in MT8188 used for HDMI, move the code flow for calculation
and setting of the DPI pixel clock to a separate function called
mtk_dpi_set_pixel_clk().

This was done because, on those platforms, the DPI instance that
is used for HDMI will get its pixel clock from the HDMI clock,
hence it is not necessary, nor desirable, to calculate or set
the pixel clock in DPI.

Reviewed-by: CK Hu <[email protected]>
Signed-off-by: AngeloGioacchino Del Regno <[email protected]>
Link: https://patchwork.kernel.org/project/dri-devel/patch/[email protected]/
Signed-off-by: Chun-Kuang Hu <[email protected]>

Author: AngeloGioacchino Del Regno

drivers/gpu/drm/mediatek/mtk_dpi.c

@@ -537,26 +537,17 @@ static unsigned int mtk_dpi_calculate_factor(struct mtk_dpi *dpi, int mode_clk)
 	return dpi_factor[dpi->conf->num_dpi_factor - 1].factor;
 }
 
-static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
-				    struct drm_display_mode *mode)
+static void mtk_dpi_set_pixel_clk(struct mtk_dpi *dpi, struct videomode *vm, int mode_clk)
 {
-	struct mtk_dpi_polarities dpi_pol;
-	struct mtk_dpi_sync_param hsync;
-	struct mtk_dpi_sync_param vsync_lodd = { 0 };
-	struct mtk_dpi_sync_param vsync_leven = { 0 };
-	struct mtk_dpi_sync_param vsync_rodd = { 0 };
-	struct mtk_dpi_sync_param vsync_reven = { 0 };
-	struct videomode vm = { 0 };
 	unsigned long pll_rate;
 	unsigned int factor;
 
 	/* let pll_rate can fix the valid range of tvdpll (1G~2GHz) */
-	factor = mtk_dpi_calculate_factor(dpi, mode->clock);
-	drm_display_mode_to_videomode(mode, &vm);
-	pll_rate = vm.pixelclock * factor;
+	factor = mtk_dpi_calculate_factor(dpi, mode_clk);
+	pll_rate = vm->pixelclock * factor;
 
 	dev_dbg(dpi->dev, "Want PLL %lu Hz, pixel clock %lu Hz\n",
-		pll_rate, vm.pixelclock);
+		pll_rate, vm->pixelclock);
 
 	clk_set_rate(dpi->tvd_clk, pll_rate);
 	pll_rate = clk_get_rate(dpi->tvd_clk);
@@ -566,20 +557,34 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
 	 * pixels for each iteration: divide the clock by this number and
 	 * adjust the display porches accordingly.
 	 */
-	vm.pixelclock = pll_rate / factor;
-	vm.pixelclock /= dpi->conf->pixels_per_iter;
+	vm->pixelclock = pll_rate / factor;
+	vm->pixelclock /= dpi->conf->pixels_per_iter;
 
 	if ((dpi->output_fmt == MEDIA_BUS_FMT_RGB888_2X12_LE) ||
 	    (dpi->output_fmt == MEDIA_BUS_FMT_RGB888_2X12_BE))
-		clk_set_rate(dpi->pixel_clk, vm.pixelclock * 2);
+		clk_set_rate(dpi->pixel_clk, vm->pixelclock * 2);
 	else
-		clk_set_rate(dpi->pixel_clk, vm.pixelclock);
+		clk_set_rate(dpi->pixel_clk, vm->pixelclock);
 
-
-	vm.pixelclock = clk_get_rate(dpi->pixel_clk);
+	vm->pixelclock = clk_get_rate(dpi->pixel_clk);
 
 	dev_dbg(dpi->dev, "Got  PLL %lu Hz, pixel clock %lu Hz\n",
-		pll_rate, vm.pixelclock);
+		pll_rate, vm->pixelclock);
+}
+
+static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
+				    struct drm_display_mode *mode)
+{
+	struct mtk_dpi_polarities dpi_pol;
+	struct mtk_dpi_sync_param hsync;
+	struct mtk_dpi_sync_param vsync_lodd = { 0 };
+	struct mtk_dpi_sync_param vsync_leven = { 0 };
+	struct mtk_dpi_sync_param vsync_rodd = { 0 };
+	struct mtk_dpi_sync_param vsync_reven = { 0 };
+	struct videomode vm = { 0 };
+
+	drm_display_mode_to_videomode(mode, &vm);
+	mtk_dpi_set_pixel_clk(dpi, &vm, mode->clock);
 
 	dpi_pol.ck_pol = MTK_DPI_POLARITY_FALLING;
 	dpi_pol.de_pol = MTK_DPI_POLARITY_RISING;