regmap: Split raw writes that cross window boundaries

If a block write covers a paged memory region and crosses a window
boundary then rather than failing the write split the transfer up
into multiple writes, making the whole process more transparent for
drivers.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 24 insertions, 2 deletions

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index baf9586b4fd8..96253cd949e9 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -852,8 +852,30 @@ static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 
         range = _regmap_range_lookup(map, reg);
         if (range) {
-                ret = _regmap_select_page(map, &reg, range,
-                                          val_len / map->format.val_bytes);
+                int val_num = val_len / map->format.val_bytes;
+                int win_offset = (reg - range->range_min) % range->window_len;
+                int win_residue = range->window_len - win_offset;
+
+                /* If the write goes beyond the end of the window split it */
+                while (val_num > win_residue) {
+                        dev_dbg(map->dev, "Writing window %d/%d\n",
+                                win_residue, val_len / map->format.val_bytes);
+                        ret = _regmap_raw_write(map, reg, val, win_residue *
+                                                map->format.val_bytes);
+                        if (ret != 0)
+                                return ret;
+
+                        reg += win_residue;
+                        val_num -= win_residue;
+                        val += win_residue * map->format.val_bytes;
+                        val_len -= win_residue * map->format.val_bytes;
+
+                        win_offset = (reg - range->range_min) %
+                                range->window_len;
+                        win_residue = range->window_len - win_offset;
+                }
+
+                ret = _regmap_select_page(map, &reg, range, val_num);
                 if (ret != 0)
                         return ret;
         }