drm/msm/dsi: Reset both PHYs before clock operation for dual DSI

In case of dual DSI, some registers in PHY1 have been programmed
during PLL0 clock's set_rate. The PHY1 reset called by host1 later
will silently reset those PHY1 registers. This change is to reset
and enable both PHYs before any PLL clock operation.

[Originally worked on by Hai Li <hali@codeaurora.org>. Fixed up
by Archit Taneja <architt@codeaurora.org>]
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/dsi/dsi.h

@@ -166,6 +166,7 @@ int msm_dsi_host_register(struct mipi_dsi_host *host, bool check_defer);
 void msm_dsi_host_unregister(struct mipi_dsi_host *host);
 int msm_dsi_host_set_src_pll(struct mipi_dsi_host *host,
 			struct msm_dsi_pll *src_pll);
+void msm_dsi_host_reset_phy(struct mipi_dsi_host *host);
 void msm_dsi_host_destroy(struct mipi_dsi_host *host);
 int msm_dsi_host_modeset_init(struct mipi_dsi_host *host,
 					struct drm_device *dev);

drivers/gpu/drm/msm/dsi/dsi_host.c

@@ -691,17 +691,6 @@ static int dsi_calc_clk_rate(struct msm_dsi_host *msm_host)
 	return 0;
 }
 
-static void dsi_phy_sw_reset(struct msm_dsi_host *msm_host)
-{
-	DBG("");
-	dsi_write(msm_host, REG_DSI_PHY_RESET, DSI_PHY_RESET_RESET);
-	/* Make sure fully reset */
-	wmb();
-	udelay(1000);
-	dsi_write(msm_host, REG_DSI_PHY_RESET, 0);
-	udelay(100);
-}
-
 static void dsi_intr_ctrl(struct msm_dsi_host *msm_host, u32 mask, int enable)
 {
 	u32 intr;
@@ -2126,6 +2115,19 @@ int msm_dsi_host_set_src_pll(struct mipi_dsi_host *host,
 	return ret;
 }
 
+void msm_dsi_host_reset_phy(struct mipi_dsi_host *host)
+{
+	struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
+
+	DBG("");
+	dsi_write(msm_host, REG_DSI_PHY_RESET, DSI_PHY_RESET_RESET);
+	/* Make sure fully reset */
+	wmb();
+	udelay(1000);
+	dsi_write(msm_host, REG_DSI_PHY_RESET, 0);
+	udelay(100);
+}
+
 int msm_dsi_host_enable(struct mipi_dsi_host *host)
 {
 	struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
@@ -2206,7 +2208,6 @@ int msm_dsi_host_power_on(struct mipi_dsi_host *host)
 		goto fail_disable_reg;
 	}
 
-	dsi_phy_sw_reset(msm_host);
 	ret = msm_dsi_manager_phy_enable(msm_host->id,
 					msm_host->byte_clk_rate * 8,
 					msm_host->esc_clk_rate,

drivers/gpu/drm/msm/dsi/dsi_manager.c

@@ -669,13 +669,39 @@ int msm_dsi_manager_phy_enable(int id,
 		struct msm_dsi_phy_shared_timings *shared_timings)
 {
 	struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
+	struct msm_dsi *mdsi = dsi_mgr_get_dsi(DSI_CLOCK_MASTER);
+	struct msm_dsi *sdsi = dsi_mgr_get_dsi(DSI_CLOCK_SLAVE);
 	struct msm_dsi_phy *phy = msm_dsi->phy;
 	int src_pll_id = IS_DUAL_DSI() ? DSI_CLOCK_MASTER : id;
 	int ret;
 
-	ret = msm_dsi_phy_enable(phy, src_pll_id, bit_rate, esc_rate);
+	/* In case of dual DSI, some registers in PHY1 have been programmed
+	 * during PLL0 clock's set_rate. The PHY1 reset called by host1 here
+	 * will silently reset those PHY1 registers. Therefore we need to reset
+	 * and enable both PHYs before any PLL clock operation.
+	 */
+	if (IS_DUAL_DSI() && mdsi && sdsi) {
+		if (!mdsi->phy_enabled && !sdsi->phy_enabled) {
+			msm_dsi_host_reset_phy(mdsi->host);
+			msm_dsi_host_reset_phy(sdsi->host);
+			ret = msm_dsi_phy_enable(mdsi->phy, src_pll_id,
+						 bit_rate, esc_rate);
+			if (ret)
+				return ret;
+			ret = msm_dsi_phy_enable(sdsi->phy, src_pll_id,
+						 bit_rate, esc_rate);
+			if (ret) {
+				msm_dsi_phy_disable(mdsi->phy);
+				return ret;
+			}
+		}
+	} else {
+		msm_dsi_host_reset_phy(msm_dsi->host);
+		ret = msm_dsi_phy_enable(msm_dsi->phy, src_pll_id, bit_rate,
+								esc_rate);
 		if (ret)
 			return ret;
+	}
 
 	msm_dsi->phy_enabled = true;
 	msm_dsi_phy_get_shared_timings(phy, shared_timings);