drm/msm/dsi: Add support for SM8750

Add support for DSI on Qualcomm SM8750 SoC with notable difference:

DSI PHY PLLs, the parents of pixel and byte clocks, cannot be used as
parents before DSI PHY is configured, the PLLs are prepared and their
initial rate is set.  Therefore assigned-clock-parents are not working
here and driver is responsible for reparenting clocks with proper
procedure: see dsi_clk_init_6g_v2_9().

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/659619/
Link: https://lore.kernel.org/r/20250618-b4-sm8750-display-v7-7-a591c609743d@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 4d75529c0e85..6400f72a66f0 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -119,6 +119,15 @@ struct msm_dsi_host {
 	struct clk *pixel_clk;
 	struct clk *byte_intf_clk;
 
+	/*
+	 * Clocks which needs to be properly parented between DISPCC and DSI PHY
+	 * PLL:
+	 */
+	struct clk *byte_src_clk;
+	struct clk *pixel_src_clk;
+	struct clk *dsi_pll_byte_clk;
+	struct clk *dsi_pll_pixel_clk;
+
 	unsigned long byte_clk_rate;
 	unsigned long byte_intf_clk_rate;
 	unsigned long pixel_clk_rate;
@@ -269,6 +278,38 @@ int dsi_clk_init_6g_v2(struct msm_dsi_host *msm_host)
 	return ret;
 }
 
+int dsi_clk_init_6g_v2_9(struct msm_dsi_host *msm_host)
+{
+	struct device *dev = &msm_host->pdev->dev;
+	int ret;
+
+	ret = dsi_clk_init_6g_v2(msm_host);
+	if (ret)
+		return ret;
+
+	msm_host->byte_src_clk = devm_clk_get(dev, "byte_src");
+	if (IS_ERR(msm_host->byte_src_clk))
+		return dev_err_probe(dev, PTR_ERR(msm_host->byte_src_clk),
+				     "can't get byte_src clock\n");
+
+	msm_host->dsi_pll_byte_clk = devm_clk_get(dev, "dsi_pll_byte");
+	if (IS_ERR(msm_host->dsi_pll_byte_clk))
+		return dev_err_probe(dev, PTR_ERR(msm_host->dsi_pll_byte_clk),
+				     "can't get dsi_pll_byte clock\n");
+
+	msm_host->pixel_src_clk = devm_clk_get(dev, "pixel_src");
+	if (IS_ERR(msm_host->pixel_src_clk))
+		return dev_err_probe(dev, PTR_ERR(msm_host->pixel_src_clk),
+				     "can't get pixel_src clock\n");
+
+	msm_host->dsi_pll_pixel_clk = devm_clk_get(dev, "dsi_pll_pixel");
+	if (IS_ERR(msm_host->dsi_pll_pixel_clk))
+		return dev_err_probe(dev, PTR_ERR(msm_host->dsi_pll_pixel_clk),
+				     "can't get dsi_pll_pixel clock\n");
+
+	return 0;
+}
+
 static int dsi_clk_init(struct msm_dsi_host *msm_host)
 {
 	struct platform_device *pdev = msm_host->pdev;
@@ -370,6 +411,26 @@ int dsi_link_clk_set_rate_6g(struct msm_dsi_host *msm_host)
 	return 0;
 }
 
+int dsi_link_clk_set_rate_6g_v2_9(struct msm_dsi_host *msm_host)
+{
+	struct device *dev = &msm_host->pdev->dev;
+	int ret;
+
+	/*
+	 * DSI PHY PLLs have to be enabled to allow reparenting to them, so
+	 * cannot use assigned-clock-parents.
+	 */
+	ret = clk_set_parent(msm_host->byte_src_clk, msm_host->dsi_pll_byte_clk);
+	if (ret)
+		dev_err(dev, "Failed to parent byte_src -> dsi_pll_byte: %d\n", ret);
+
+	ret = clk_set_parent(msm_host->pixel_src_clk, msm_host->dsi_pll_pixel_clk);
+	if (ret)
+		dev_err(dev, "Failed to parent pixel_src -> dsi_pll_pixel: %d\n", ret);
+
+	return dsi_link_clk_set_rate_6g(msm_host);
+}
+
 int dsi_link_clk_enable_6g(struct msm_dsi_host *msm_host)
 {
 	int ret;