This patch creates a connector specific debugfs
interface to read any particular DPCD register.
The DPCD register address (hex format) is written
to 'i915_dpcd_addr' interface and the corresponding
value can be read from 'i915_dpcd_val' interface.
To write into a DPCD register, echo a value into
'i915_dpcd_val' interface. This will return -EIO
for invalid writes.
Example usage:
echo 0x2 > i915_dpcd_addr
cat i915_dpcd_val
0x84
To write 0x1 to DPCD 0x170:
echo 0x170 > i915_dpcd_addr
echo 0x1 > i915_dpcd_val
cat i915_dpcd_val
0x1
v2: Address Jani's comments.
v3: Added capability to write DPCD also (Ville)
Signed-off-by: Durgadoss R <durgadoss.r@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_debugfs.c | 120 +++++++++++++++++++++++++++++++++++-
drivers/gpu/drm/i915/intel_drv.h | 1 +
2 files changed, 120 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 9c2b9e4..79c876e 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4968,6 +4968,119 @@ static const struct file_operations i915_dpcd_fops = {
.release = single_release,
};
+static ssize_t i915_dpcd_addr_write(struct file *file, const char __user *ubuf,
+ size_t len, loff_t *offp)
+{
+ struct seq_file *m = file->private_data;
+ struct drm_connector *connector = m->private;
+ struct intel_dp *intel_dp =
+ enc_to_intel_dp(&intel_attached_encoder(connector)->base);
+ unsigned int reg_addr;
+ char tmp[16];
+
+ if (len >= sizeof(tmp))
+ return -EINVAL;
+
+ if (copy_from_user(tmp, ubuf, len))
+ return -EFAULT;
+
+ tmp[len] = '\0';
+
+ if (kstrtouint(tmp, 16, ®_addr))
+ return -EINVAL;
+
+ intel_dp->debugfs_dpcd_addr = reg_addr;
+
+ return len;
+}
+
+static int i915_dpcd_addr_show(struct seq_file *m, void *data)
+{
+ struct drm_connector *connector = m->private;
+ struct intel_dp *intel_dp =
+ enc_to_intel_dp(&intel_attached_encoder(connector)->base);
+
+ seq_printf(m, "0x%x\n", intel_dp->debugfs_dpcd_addr);
+
+ return 0;
+}
+
+static int i915_dpcd_addr_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, i915_dpcd_addr_show, inode->i_private);
+}
+
+static const struct file_operations i915_dpcd_addr_fops = {
+ .owner = THIS_MODULE,
+ .open = i915_dpcd_addr_open,
+ .read = seq_read,
+ .write = i915_dpcd_addr_write,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static ssize_t i915_dpcd_val_write(struct file *file, const char __user *ubuf,
+ size_t len, loff_t *offp)
+{
+ struct seq_file *m = file->private_data;
+ struct drm_connector *connector = m->private;
+ struct intel_dp *intel_dp =
+ enc_to_intel_dp(&intel_attached_encoder(connector)->base);
+ unsigned int addr = intel_dp->debugfs_dpcd_addr;
+ unsigned int val;
+ char tmp[16];
+ int ret;
+
+ if (len >= sizeof(tmp))
+ return -EINVAL;
+
+ if (copy_from_user(tmp, ubuf, len))
+ return -EFAULT;
+
+ tmp[len] = '\0';
+
+ if (kstrtouint(tmp, 16, &val))
+ return -EINVAL;
+
+ ret = drm_dp_dpcd_writeb(&intel_dp->aux, addr, val);
+ if (ret < 0)
+ return ret;
+
+ return len;
+}
+
+static int i915_dpcd_val_show(struct seq_file *m, void *data)
+{
+ struct drm_connector *connector = m->private;
+ struct intel_dp *intel_dp =
+ enc_to_intel_dp(&intel_attached_encoder(connector)->base);
+ unsigned int addr;
+ u8 val;
+ int ret;
+
+ addr = intel_dp->debugfs_dpcd_addr;
+ ret = drm_dp_dpcd_readb(&intel_dp->aux, addr, &val);
+ if (ret < 0)
+ return ret;
+
+ seq_printf(m, "0x%x\n", val);
+ return 0;
+}
+
+static int i915_dpcd_val_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, i915_dpcd_val_show, inode->i_private);
+}
+
+static const struct file_operations i915_dpcd_val_fops = {
+ .owner = THIS_MODULE,
+ .open = i915_dpcd_val_open,
+ .read = seq_read,
+ .write = i915_dpcd_val_write,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
/**
* i915_debugfs_connector_add - add i915 specific connector debugfs files
* @connector: pointer to a registered drm_connector
@@ -4986,9 +5099,14 @@ int i915_debugfs_connector_add(struct drm_connector *connector)
return -ENODEV;
if (connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
- connector->connector_type == DRM_MODE_CONNECTOR_eDP)
+ connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
debugfs_create_file("i915_dpcd", S_IRUGO, root, connector,
&i915_dpcd_fops);
+ debugfs_create_file("i915_dpcd_addr", S_IRUGO | S_IWUSR,
+ root, connector, &i915_dpcd_addr_fops);
+ debugfs_create_file("i915_dpcd_val", S_IRUGO | S_IWUSR,
+ root, connector, &i915_dpcd_val_fops);
+ }
return 0;
}
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 23a42a4..4477d14 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -709,6 +709,7 @@ struct intel_dp {
unsigned long last_power_cycle;
unsigned long last_power_on;
unsigned long last_backlight_off;
+ unsigned int debugfs_dpcd_addr;
struct notifier_block edp_notifier;
--
1.9.1
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