Subject: Re: [PATCH 2/5] iommu/arm-smmu-v3: Add register display to debugfs

From: Nicolin Chen <[email-masked]>
Date: Tue, 26 May 2026 18:28:12 -0700

On Wed, May 20, 2026 at 02:37:08PM +0800, Qinxin Xia wrote:
> +static int smmu_debugfs_registers_open(struct inode *inode, struct file *file)
> +{
> +	struct arm_smmu_device *smmu = inode->i_private;
> +	int ret;
> +
> +	if (!smmu || !get_device(smmu->dev))
> +		return -ENODEV;
> +
> +	ret = single_open(file, smmu_debugfs_registers_show, smmu);
> +	if (ret)
> +		put_device(smmu->dev);
> +
> +	return ret;
> +}
> +
> +static int smmu_debugfs_registers_release(struct inode *inode, struct file *file)
> +{
> +	struct seq_file *seq = file->private_data;
> +	struct arm_smmu_device *smmu = seq->private;
> +
> +	single_release(inode, file);
> +	if (smmu)
> +		put_device(smmu->dev);
> +
> +	return 0;
> +}
> +
> +static const struct file_operations smmu_debugfs_registers_fops = {
> +	.owner   = THIS_MODULE,
> +	.open    = smmu_debugfs_registers_open,
> +	.read    = seq_read,
> +	.llseek  = seq_lseek,
> +	.release = smmu_debugfs_registers_release,
> +};

These seem a bit redundant; only names and show functions are
different from the cap's fops/open/release?

If so, maybe we can mimic how drivers/usb/host/xhci-debugfs.c
unify things (refer to w_context_files).

Nicolin