3 files changed, 78 insertions, 15 deletions

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index d744ae3926dd..fc554e357c5d 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -146,6 +146,10 @@ struct regmap {
         /* if set, the device supports multi write mode */
         bool can_multi_write;
 
+        /* if set, raw reads/writes are limited to this size */
+        size_t max_raw_read;
+        size_t max_raw_write;
+
         struct rb_root range_tree;
         void *selector_work_buf;        /* Scratch buffer used for selector */
 };
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index a6b6f7ee87ee..7cbe42680877 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -579,6 +579,8 @@ struct regmap *regmap_init(struct device *dev,
         map->use_single_read = config->use_single_rw || !bus || !bus->read;
         map->use_single_write = config->use_single_rw || !bus || !bus->write;
         map->can_multi_write = config->can_multi_write && bus && bus->write;
+        map->max_raw_read = bus->max_raw_read;
+        map->max_raw_write = bus->max_raw_write;
         map->dev = dev;
         map->bus = bus;
         map->bus_context = bus_context;
@@ -1674,6 +1676,7 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 {
         int ret = 0, i;
         size_t val_bytes = map->format.val_bytes;
+        size_t total_size = val_bytes * val_count;
 
         if (map->bus && !map->format.parse_inplace)
                 return -EINVAL;
@@ -1722,16 +1725,37 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
                 }
 out:
                 map->unlock(map->lock_arg);
-        } else if (map->use_single_write) {
+        } else if (map->use_single_write ||
+                   (map->max_raw_write && map->max_raw_write < total_size)) {
+                int chunk_stride = map->reg_stride;
+                size_t chunk_size = val_bytes;
+                size_t chunk_count = val_count;
+
+                if (!map->use_single_write) {
+                        chunk_size = map->max_raw_write;
+                        if (chunk_size % val_bytes)
+                                chunk_size -= chunk_size % val_bytes;
+                        chunk_count = total_size / chunk_size;
+                        chunk_stride *= chunk_size / val_bytes;
+                }
+
                 map->lock(map->lock_arg);
-                for (i = 0; i < val_count; i++) {
+                /* Write as many bytes as possible with chunk_size */
+                for (i = 0; i < chunk_count; i++) {
                         ret = _regmap_raw_write(map,
-                                                reg + (i * map->reg_stride),
-                                                val + (i * val_bytes),
-                                                val_bytes);
+                                                reg + (i * chunk_stride),
+                                                val + (i * chunk_size),
+                                                chunk_size);
                         if (ret)
                                 break;
                 }
+
+                /* Write remaining bytes */
+                if (!ret && chunk_size * i < total_size) {
+                        ret = _regmap_raw_write(map, reg + (i * chunk_stride),
+                                                val + (i * chunk_size),
+                                                total_size - i * chunk_size);
+                }
                 map->unlock(map->lock_arg);
         } else {
                 void *wval;
@@ -2319,20 +2343,51 @@ int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
                  * Some devices does not support bulk read, for
                  * them we have a series of single read operations.
                  */
-                if (map->use_single_read) {
-                        for (i = 0; i < val_count; i++) {
-                                ret = regmap_raw_read(map,
-                                                reg + (i * map->reg_stride),
-                                                val + (i * val_bytes),
-                                                val_bytes);
-                                if (ret != 0)
-                                        return ret;
-                        }
-                } else {
+                size_t total_size = val_bytes * val_count;
+
+                if (!map->use_single_read &&
+                    (!map->max_raw_read || map->max_raw_read > total_size)) {
                         ret = regmap_raw_read(map, reg, val,
                                               val_bytes * val_count);
                         if (ret != 0)
                                 return ret;
+                } else {
+                        /*
+                         * Some devices do not support bulk read or do not
+                         * support large bulk reads, for them we have a series
+                         * of read operations.
+                         */
+                        int chunk_stride = map->reg_stride;
+                        size_t chunk_size = val_bytes;
+                        size_t chunk_count = val_count;
+
+                        if (!map->use_single_read) {
+                                chunk_size = map->max_raw_read;
+                                if (chunk_size % val_bytes)
+                                        chunk_size -= chunk_size % val_bytes;
+                                chunk_count = total_size / chunk_size;
+                                chunk_stride *= chunk_size / val_bytes;
+                        }
+
+                        /* Read bytes that fit into a multiple of chunk_size */
+                        for (i = 0; i < chunk_count; i++) {
+                                ret = regmap_raw_read(map,
+                                                      reg + (i * chunk_stride),
+                                                      val + (i * chunk_size),
+                                                      chunk_size);
+                                if (ret != 0)
+                                        return ret;
+                        }
+
+                        /* Read remaining bytes */
+                        if (chunk_size * i < total_size) {
+                                ret = regmap_raw_read(map,
+                                                      reg + (i * chunk_stride),
+                                                      val + (i * chunk_size),
+                                                      total_size - i * chunk_size);
+                                if (ret != 0)
+                                        return ret;
+                        }
                 }
 
                 for (i = 0; i < val_count * val_bytes; i += val_bytes)
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 73fc34d0c4c2..327b8f291d3f 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -311,6 +311,8 @@ typedef void (*regmap_hw_free_context)(void *context);
  * @val_format_endian_default: Default endianness for formatted register
  *     values. Used when the regmap_config specifies DEFAULT. If this is
  *     DEFAULT, BIG is assumed.
+ * @max_raw_read: Max raw read size that can be used on the bus.
+ * @max_raw_write: Max raw write size that can be used on the bus.
  */
 struct regmap_bus {
         bool fast_io;
@@ -325,6 +327,8 @@ struct regmap_bus {
         u8 read_flag_mask;
         enum regmap_endian reg_format_endian_default;
         enum regmap_endian val_format_endian_default;
+        size_t max_raw_read;
+        size_t max_raw_write;
 };
 
 struct regmap *regmap_init(struct device *dev,