regmap: Add bypassed version of regmap_multi_reg_write

Devices with more complex boot proceedures may occasionally apply the
register patch manual. regmap_multi_reg_write is a logical way to do so,
however the patch must be applied with cache bypass on, such that it
doesn't override any user settings. This patch adds a
regmap_multi_reg_write_bypassed function that applies a set of writes
with the bypass enabled.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

2 files changed, 65 insertions, 13 deletions

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 1e3934aea56a..e6a2c29c0be4 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1576,6 +1576,26 @@ out:
 }
 EXPORT_SYMBOL_GPL(regmap_bulk_write);
 
+static int _regmap_multi_reg_write(struct regmap *map,
+                                   const struct reg_default *regs,
+                                   int num_regs)
+{
+        int i, ret;
+
+        for (i = 0; i < num_regs; i++) {
+                if (regs[i].reg % map->reg_stride)
+                        return -EINVAL;
+                ret = _regmap_write(map, regs[i].reg, regs[i].def);
+                if (ret != 0) {
+                        dev_err(map->dev, "Failed to write %x = %x: %d\n",
+                                regs[i].reg, regs[i].def, ret);
+                        return ret;
+                }
+        }
+
+        return 0;
+}
+
 /*
  * regmap_multi_reg_write(): Write multiple registers to the device
  *
@@ -1595,28 +1615,57 @@ EXPORT_SYMBOL_GPL(regmap_bulk_write);
 int regmap_multi_reg_write(struct regmap *map, const struct reg_default *regs,
                            int num_regs)
 {
-        int ret = 0, i;
-
-        for (i = 0; i < num_regs; i++) {
-                int reg = regs[i].reg;
-                if (reg % map->reg_stride)
-                        return -EINVAL;
-        }
+        int ret;
 
         map->lock(map->lock_arg);
 
-        for (i = 0; i < num_regs; i++) {
-                ret = _regmap_write(map, regs[i].reg, regs[i].def);
-                if (ret != 0)
-                        goto out;
-        }
-out:
+        ret = _regmap_multi_reg_write(map, regs, num_regs);
+
         map->unlock(map->lock_arg);
 
         return ret;
 }
 EXPORT_SYMBOL_GPL(regmap_multi_reg_write);
 
+/*
+ * regmap_multi_reg_write_bypassed(): Write multiple registers to the
+ *                                    device but not the cache
+ *
+ * where the set of register are supplied in any order
+ *
+ * @map: Register map to write to
+ * @regs: Array of structures containing register,value to be written
+ * @num_regs: Number of registers to write
+ *
+ * This function is intended to be used for writing a large block of data
+ * atomically to the device in single transfer for those I2C client devices
+ * that implement this alternative block write mode.
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_multi_reg_write_bypassed(struct regmap *map,
+                                    const struct reg_default *regs,
+                                    int num_regs)
+{
+        int ret;
+        bool bypass;
+
+        map->lock(map->lock_arg);
+
+        bypass = map->cache_bypass;
+        map->cache_bypass = true;
+
+        ret = _regmap_multi_reg_write(map, regs, num_regs);
+
+        map->cache_bypass = bypass;
+
+        map->unlock(map->lock_arg);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_multi_reg_write_bypassed);
+
 /**
  * regmap_raw_write_async(): Write raw values to one or more registers
  *                           asynchronously
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index e97ac6c8b7be..ca2272fbd014 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -388,6 +388,9 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
                         size_t val_count);
 int regmap_multi_reg_write(struct regmap *map, const struct reg_default *regs,
                         int num_regs);
+int regmap_multi_reg_write_bypassed(struct regmap *map,
+                                    const struct reg_default *regs,
+                                    int num_regs);
 int regmap_raw_write_async(struct regmap *map, unsigned int reg,
                            const void *val, size_t val_len);
 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);