On Tue, Dec 21, 2021 at 02:42:21PM +0200, Cosmin Tanislav wrote:
> From: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
>
> Similar to IIO, create a device directory inside debugfs
> mount point, and create a direct_reg_access file inside
> that directory, if debugfs_reg_access callback is defined
> inside hwmon_ops.
>
> Signed-off-by: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>
> ---
> drivers/hwmon/hwmon.c | 122 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/hwmon.h | 12 +++++
> 2 files changed, 134 insertions(+)
>
> diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
> index 3501a3ead4ba..a3dc785cd885 100644
> --- a/drivers/hwmon/hwmon.c
> +++ b/drivers/hwmon/hwmon.c
> @@ -10,6 +10,7 @@
> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
> #include <linux/bitops.h>
> +#include <linux/debugfs.h>
> #include <linux/device.h>
> #include <linux/err.h>
> #include <linux/gfp.h>
> @@ -35,6 +36,12 @@ struct hwmon_device {
> struct list_head tzdata;
> struct attribute_group group;
> const struct attribute_group **groups;
> +#if defined(CONFIG_DEBUG_FS)
> + struct dentry *debugfs_dentry;
No need to keep this, just look it up when you want to remove it.
> + unsigned int cached_reg_addr;
> + char read_buf[20];
> + unsigned int read_buf_len;
> +#endif
> };
>
> #define to_hwmon_device(d) container_of(d, struct hwmon_device, dev)
> @@ -64,6 +71,113 @@ struct hwmon_thermal_data {
> struct thermal_zone_device *tzd;/* thermal zone device */
> };
>
> +static struct dentry *hwmon_debugfs_dentry;
> +
> +#if defined(CONFIG_DEBUG_FS)
> +static ssize_t hwmon_debugfs_read_reg(struct file *file, char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + struct hwmon_device *hwdev = file->private_data;
> + struct device *hdev = &hwdev->dev;
> + unsigned int val = 0;
> + int ret;
> +
> + if (*ppos > 0)
> + return simple_read_from_buffer(userbuf, count, ppos,
> + hwdev->read_buf,
> + hwdev->read_buf_len);
> +
> + ret = hwdev->chip->ops->debugfs_reg_access(hdev, hwdev->cached_reg_addr,
> + 0, &val);
> + if (ret) {
> + dev_err(hdev->parent, "%s: read failed\n", __func__);
> + return ret;
> + }
> +
> + hwdev->read_buf_len = snprintf(hwdev->read_buf, sizeof(hwdev->read_buf),
> + "0x%X\n", val);
> +
> + return simple_read_from_buffer(userbuf, count, ppos, hwdev->read_buf,
> + hwdev->read_buf_len);
> +}
> +
> +static ssize_t hwmon_debugfs_write_reg(struct file *file,
> + const char __user *userbuf,
> + size_t count, loff_t *ppos)
> +{
> + struct hwmon_device *hwdev = file->private_data;
> + struct device *hdev = &hwdev->dev;
> + unsigned int reg, val;
> + char buf[80];
> + int ret;
> +
> + count = min_t(size_t, count, sizeof(buf) - 1);
> + if (copy_from_user(buf, userbuf, count))
> + return -EFAULT;
> +
> + buf[count] = 0;
> +
> + ret = sscanf(buf, "%i %i", ®, &val);
> +
> + switch (ret) {
> + case 1:
> + hwdev->cached_reg_addr = reg;
> + break;
> + case 2:
> + hwdev->cached_reg_addr = reg;
> + ret = hwdev->chip->ops->debugfs_reg_access(hdev, reg, val,
> + NULL);
> + if (ret) {
> + dev_err(hdev->parent, "%s: write failed\n", __func__);
> + return ret;
> + }
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return count;
> +}
> +
> +static const struct file_operations hwmon_debugfs_reg_fops = {
> + .open = simple_open,
> + .read = hwmon_debugfs_read_reg,
> + .write = hwmon_debugfs_write_reg,
> +};
> +
> +static void hwmon_device_register_debugfs(struct hwmon_device *hwdev)
> +{
> + if (IS_ERR(hwmon_debugfs_dentry))
> + return;
Why check this?
> +
> + if (!hwdev->chip || !hwdev->chip->ops ||
> + !hwdev->chip->ops->debugfs_reg_access)
> + return;
> +
> + hwdev->debugfs_dentry = debugfs_create_dir(dev_name(&hwdev->dev),
> + hwmon_debugfs_dentry);
> +
> + if (IS_ERR(hwdev->debugfs_dentry))
> + return;
No need to check for this at all, just create the directory and move on.
thanks,
greg k-h
