regmap: debugfs: Use seq_file for the access map

Unlike the registers file we don't have any substantial performance
concerns rendering the entire file (it involves no device accesses) so
just use seq_printf() to simplify the code.

Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 18 insertions, 51 deletions

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 3f0a7e262d69..1ee3d40861c7 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -397,72 +397,39 @@ static const struct file_operations regmap_reg_ranges_fops = {
         .llseek = default_llseek,
 };
 
-static ssize_t regmap_access_read_file(struct file *file,
-                                       char __user *user_buf, size_t count,
-                                       loff_t *ppos)
+static int regmap_access_show(struct seq_file *s, void *ignored)
 {
-        int reg_len, tot_len;
-        size_t buf_pos = 0;
-        loff_t p = 0;
-        ssize_t ret;
-        int i;
-        struct regmap *map = file->private_data;
-        char *buf;
-
-        if (*ppos < 0 || !count)
-                return -EINVAL;
+        struct regmap *map = s->private;
+        int i, reg_len;
 
-        buf = kmalloc(count, GFP_KERNEL);
-        if (!buf)
-                return -ENOMEM;
-
-        /* Calculate the length of a fixed format  */
         reg_len = regmap_calc_reg_len(map->max_register);
-        tot_len = reg_len + 10; /* ': R W V P\n' */
 
         for (i = 0; i <= map->max_register; i += map->reg_stride) {
                 /* Ignore registers which are neither readable nor writable */
                 if (!regmap_readable(map, i) && !regmap_writeable(map, i))
                         continue;
 
-                /* If we're in the region the user is trying to read */
-                if (p >= *ppos) {
-                        /* ...but not beyond it */
-                        if (buf_pos + tot_len + 1 >= count)
-                                break;
-
-                        /* Format the register */
-                        snprintf(buf + buf_pos, count - buf_pos,
-                                 "%.*x: %c %c %c %c\n",
-                                 reg_len, i,
-                                 regmap_readable(map, i) ? 'y' : 'n',
-                                 regmap_writeable(map, i) ? 'y' : 'n',
-                                 regmap_volatile(map, i) ? 'y' : 'n',
-                                 regmap_precious(map, i) ? 'y' : 'n');
-
-                        buf_pos += tot_len;
-                }
-                p += tot_len;
-        }
-
-        ret = buf_pos;
-
-        if (copy_to_user(user_buf, buf, buf_pos)) {
-                ret = -EFAULT;
-                goto out;
+                /* Format the register */
+                seq_printf(s, "%.*x: %c %c %c %c\n", reg_len, i,
+                           regmap_readable(map, i) ? 'y' : 'n',
+                           regmap_writeable(map, i) ? 'y' : 'n',
+                           regmap_volatile(map, i) ? 'y' : 'n',
+                           regmap_precious(map, i) ? 'y' : 'n');
         }
 
-        *ppos += buf_pos;
+        return 0;
+}
 
-out:
-        kfree(buf);
-        return ret;
+static int access_open(struct inode *inode, struct file *file)
+{
+        return single_open(file, regmap_access_show, inode->i_private);
 }
 
 static const struct file_operations regmap_access_fops = {
-        .open = simple_open,
-        .read = regmap_access_read_file,
-        .llseek = default_llseek,
+        .open           = access_open,
+        .read           = seq_read,
+        .llseek         = seq_lseek,
+        .release        = single_release,
 };
 
 static ssize_t regmap_cache_only_write_file(struct file *file,