drm/bridge/synopsys: dsi: Allow VPG to be enabled via debugfs

The Synopsys MIPI DSI IP contains a video test pattern generator which
is helpful in debugging video timing with connected displays.
Add a debugfs directory containing files which allow the VPG to be
enabled and disabled, and its orientation to be changed.

Signed-off-by: Matt Redfearn <matt.redfearn@thinci.com>
Tested-by: Yannick Fertré <yannick.fertre@st.com>
Reviewed-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190430081646.23845-1-matt.redfearn@thinci.com

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index 281c58b..675442b 100644 (file)
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -10,6 +10,7 @@
 
 #include <linux/clk.h>
 #include <linux/component.h>
+#include <linux/debugfs.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
@@ -89,6 +90,8 @@
 #define VID_MODE_TYPE_NON_BURST_SYNC_EVENTS    0x1
 #define VID_MODE_TYPE_BURST                    0x2
 #define VID_MODE_TYPE_MASK                     0x3
+#define VID_MODE_VPG_ENABLE            BIT(16)
+#define VID_MODE_VPG_HORIZONTAL                BIT(24)
 
 #define DSI_VID_PKT_SIZE               0x3c
 #define VID_PKT_SIZE(p)                        ((p) & 0x3fff)
@@ -233,6 +236,13 @@ struct dw_mipi_dsi {
        u32 format;
        unsigned long mode_flags;
 
+#ifdef CONFIG_DEBUG_FS
+       struct dentry *debugfs;
+
+       bool vpg;
+       bool vpg_horizontal;
+#endif /* CONFIG_DEBUG_FS */
+
        struct dw_mipi_dsi *master; /* dual-dsi master ptr */
        struct dw_mipi_dsi *slave; /* dual-dsi slave ptr */
 
@@ -518,6 +528,13 @@ static void dw_mipi_dsi_video_mode_config(struct dw_mipi_dsi *dsi)
        else
                val |= VID_MODE_TYPE_NON_BURST_SYNC_EVENTS;
 
+#ifdef CONFIG_DEBUG_FS
+       if (dsi->vpg) {
+               val |= VID_MODE_VPG_ENABLE;
+               val |= dsi->vpg_horizontal ? VID_MODE_VPG_HORIZONTAL : 0;
+       }
+#endif /* CONFIG_DEBUG_FS */
+
        dsi_write(dsi, DSI_VID_MODE_CFG, val);
 }
 
@@ -930,6 +947,33 @@ static const struct drm_bridge_funcs dw_mipi_dsi_bridge_funcs = {
        .attach       = dw_mipi_dsi_bridge_attach,
 };
 
+#ifdef CONFIG_DEBUG_FS
+
+static void dw_mipi_dsi_debugfs_init(struct dw_mipi_dsi *dsi)
+{
+       dsi->debugfs = debugfs_create_dir(dev_name(dsi->dev), NULL);
+       if (IS_ERR(dsi->debugfs)) {
+               dev_err(dsi->dev, "failed to create debugfs root\n");
+               return;
+       }
+
+       debugfs_create_bool("vpg", 0660, dsi->debugfs, &dsi->vpg);
+       debugfs_create_bool("vpg_horizontal", 0660, dsi->debugfs,
+                           &dsi->vpg_horizontal);
+}
+
+static void dw_mipi_dsi_debugfs_remove(struct dw_mipi_dsi *dsi)
+{
+       debugfs_remove_recursive(dsi->debugfs);
+}
+
+#else
+
+static void dw_mipi_dsi_debugfs_init(struct dw_mipi_dsi *dsi) { }
+static void dw_mipi_dsi_debugfs_remove(struct dw_mipi_dsi *dsi) { }
+
+#endif /* CONFIG_DEBUG_FS */
+
 static struct dw_mipi_dsi *
 __dw_mipi_dsi_probe(struct platform_device *pdev,
                    const struct dw_mipi_dsi_plat_data *plat_data)
@@ -1000,6 +1044,7 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
                clk_disable_unprepare(dsi->pclk);
        }
 
+       dw_mipi_dsi_debugfs_init(dsi);
        pm_runtime_enable(dev);
 
        dsi->dsi_host.ops = &dw_mipi_dsi_host_ops;
@@ -1007,6 +1052,7 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
        ret = mipi_dsi_host_register(&dsi->dsi_host);
        if (ret) {
                dev_err(dev, "Failed to register MIPI host: %d\n", ret);
+               dw_mipi_dsi_debugfs_remove(dsi);
                return ERR_PTR(ret);
        }
 
@@ -1024,6 +1070,7 @@ static void __dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
        mipi_dsi_host_unregister(&dsi->dsi_host);
 
        pm_runtime_disable(dsi->dev);
+       dw_mipi_dsi_debugfs_remove(dsi);
 }
 
 void dw_mipi_dsi_set_slave(struct dw_mipi_dsi *dsi, struct dw_mipi_dsi *slave)