regmap: add MMIO bus support

This is a basic memory-mapped-IO bus for regmap. It has the following
features and limitations:

* Registers themselves may be 8, 16, 32, or 64-bit. 64-bit is only
  supported on 64-bit platforms.
* Register offsets are limited to precisely 32-bit.
* IO is performed using readl/writel, with no provision for using the
  __raw_readl or readl_relaxed variants.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index f14588a96eaf..f6abc8d33d64 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -137,6 +137,9 @@ struct regmap *regmap_init_i2c(struct i2c_client *i2c,
                                const struct regmap_config *config);
 struct regmap *regmap_init_spi(struct spi_device *dev,
                                const struct regmap_config *config);
+struct regmap *regmap_init_mmio(struct device *dev,
+                                void __iomem *regs,
+                                const struct regmap_config *config);
 
 struct regmap *devm_regmap_init(struct device *dev,
                                 const struct regmap_bus *bus,
@@ -146,6 +149,9 @@ struct regmap *devm_regmap_init_i2c(struct i2c_client *i2c,
                                     const struct regmap_config *config);
 struct regmap *devm_regmap_init_spi(struct spi_device *dev,
                                     const struct regmap_config *config);
+struct regmap *devm_regmap_init_mmio(struct device *dev,
+                                     void __iomem *regs,
+                                     const struct regmap_config *config);
 
 void regmap_exit(struct regmap *map);
 int regmap_reinit_cache(struct regmap *map,