[PATCH v6 41/42] drm/mediatek: mtk_hdmi_v2: Add debugfs ops and implement ABIST

AngeloGioacchino Del Regno
2025-02-11T11:35:22Z

Implement the Automated Built-In Self-Test ABIST functionality
provided by the HDMIv2 IP and expose it through the "hdmi_abist"
debugfs file.

Write "1" to this file to activate ABIST, or "0" to deactivate.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
drivers/gpu/drm/mediatek/mtk_hdmi_v2.c | 123 +++++++++++++++++++++++++
1 file changed, 123 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c b/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c
index 36b7f8d8d218..f4a086b92dae 100644
--- a/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c
+++ b/drivers/gpu/drm/mediatek/mtk_hdmi_v2.c
@@ -1170,6 +1170,128 @@ static int mtk_hdmi_v2_hdmi_write_infoframe(struct drm_bridge *bridge,
return 0;
}

+static int mtk_hdmi_v2_set_abist(struct mtk_hdmi *hdmi, bool enable)
+{
+ struct drm_display_mode *mode = &hdmi->mode;
+ int abist_format = -EINVAL;
+ bool interlaced;
+
+ if (!enable) {
+ regmap_clear_bits(hdmi->regs, TOP_CFG00, HDMI_ABIST_ENABLE);
+ return 0;
+ }
+
+ if (!mode->hdisplay || !mode->vdisplay)
+ return -EINVAL;
+
+ interlaced = mode->flags & DRM_MODE_FLAG_INTERLACE;
+
+ switch (mode->hdisplay) {
+ case 720:
+ if (mode->vdisplay == 480)
+ abist_format = 2;
+ else if (mode->vdisplay == 576)
+ abist_format = 11;
+ break;
+ case 1280:
+ if (mode->vdisplay == 720)
+ abist_format = 3;
+ break;
+ case 1440:
+ if (mode->vdisplay == 480)
+ abist_format = interlaced ? 5 : 9;
+ else if (mode->vdisplay == 576)
+ abist_format = interlaced ? 14 : 18;
+ break;
+ case 1920:
+ if (mode->vdisplay == 1080)
+ abist_format = interlaced ? 4 : 10;
+ break;
+ case 3840:
+ if (mode->vdisplay == 2160)
+ abist_format = 25;
+ break;
+ case 4096:
+ if (mode->vdisplay == 2160)
+ abist_format = 26;
+ break;
+ default:
+ break;
+ }
+ if (!abist_format)
+ return -EINVAL;
+
+ regmap_update_bits(hdmi->regs, TOP_CFG00, HDMI_ABIST_VIDEO_FORMAT,
+ FIELD_PREP(HDMI_ABIST_VIDEO_FORMAT, abist_format));
+ regmap_set_bits(hdmi->regs, TOP_CFG00, HDMI_ABIST_ENABLE);
+ return 0;
+}
+
+static int mtk_hdmi_v2_debug_abist_show(struct seq_file *m, void *arg)
+{
+ struct mtk_hdmi *hdmi = m->private;
+ bool en;
+ u32 val;
+ int ret;
+
+ if (!hdmi)
+ return -EINVAL;
+
+ ret = regmap_read(hdmi->regs, TOP_CFG00, &val);
+ if (ret)
+ return ret;
+
+ en = FIELD_GET(HDMI_ABIST_ENABLE, val);
+
+ seq_printf(m, "HDMI Automated Built-In Self Test: %s\n",
+ en ? "Enabled" : "Disabled");
+
+ return 0;
+}
+
+static ssize_t mtk_hdmi_v2_debug_abist_write(struct file *file,
+ const char __user *ubuf,
+ size_t len, loff_t *offp)
+{
+ struct seq_file *m = file->private_data;
+ int ret;
+ u32 en;
+
+ if (!m || !m->private || *offp)
+ return -EINVAL;
+
+ ret = kstrtouint_from_user(ubuf, len, 0, &en);
+ if (ret)
+ return ret;
+
+ if (en < 0 || en > 1)
+ return -EINVAL;
+
+ mtk_hdmi_v2_set_abist((struct mtk_hdmi *)m->private, en);
+ return len;
+}
+
+static int mtk_hdmi_v2_debug_abist_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, mtk_hdmi_v2_debug_abist_show, inode->i_private);
+}
+
+static const struct file_operations mtk_hdmi_debug_abist_fops = {
+ .owner = THIS_MODULE,
+ .open = mtk_hdmi_v2_debug_abist_open,
+ .read = seq_read,
+ .write = mtk_hdmi_v2_debug_abist_write,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static void mtk_hdmi_v2_debugfs_init(struct drm_bridge *bridge, struct dentry *root)
+{
+ struct mtk_hdmi *dpi = hdmi_ctx_from_bridge(bridge);
+
+ debugfs_create_file("hdmi_abist", 0640, root, dpi, &mtk_hdmi_debug_abist_fops);
+}
+
static const struct drm_bridge_funcs mtk_v2_hdmi_bridge_funcs = {
.attach = mtk_hdmi_v2_bridge_attach,
.detach = mtk_hdmi_v2_bridge_detach,
@@ -1189,6 +1311,7 @@ static const struct drm_bridge_funcs mtk_v2_hdmi_bridge_funcs = {
.hdmi_tmds_char_rate_valid = mtk_hdmi_v2_hdmi_tmds_char_rate_valid,
.hdmi_clear_infoframe = mtk_hdmi_v2_hdmi_clear_infoframe,
.hdmi_write_infoframe = mtk_hdmi_v2_hdmi_write_infoframe,
+ .debugfs_init = mtk_hdmi_v2_debugfs_init,
};

/*
--
2.48.1