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>

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index baf9586b4fd8d230772b50efb099123524717218..96253cd949e98cddbf433e68913b6c4051d337fa 100644 (file)
--- 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;
        }