regmap: Add regmap dummy driver

Add a pseudo-driver for debugging and stress-testing the regmap/regcache APIs. A standard set of tools for working with this driver (mainly sh scripts) will be put in a repo at https://github.com/quantumdream/regmap-tools.

---
This is an initial implementation of the regdummy driver for regmap.

This is mainly useful for debugging/stress-testing regcache as it removes the need for real hardware and can be done in an emulated environment very easily.

There'll be incremental patches adding more features such as, support for configurable volatile/readable/etc. registers via debugfs entries.

 drivers/base/regmap/Kconfig        |   8 +
 drivers/base/regmap/Makefile       |   1 +
 drivers/base/regmap/regmap-dummy.c | 599 +++++++++++++++++++++++++++++++++++++
 3 files changed, 608 insertions(+)
 create mode 100644 drivers/base/regmap/regmap-dummy.c

index 6be390b..5a1ab02 100644
@@ -20,3 +20,11 @@ config REGMAP_MMIO
 
 config REGMAP_IRQ
 	bool
+
+config REGMAP_DUMMY
+	tristate
+	select REGMAP_MMIO
+	help
+	  Say Y or M if you want to add the regdummy driver for regmap.
+	  This is a pseudo-driver used for debugging and stress-testing
+	  the regmap/regcache APIs.

index 5e75d1b..c5d70f1 100644
@@ -5,3 +5,4 @@ obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
 obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o
 obj-$(CONFIG_REGMAP_MMIO) += regmap-mmio.o
 obj-$(CONFIG_REGMAP_IRQ) += regmap-irq.o
+obj-$(CONFIG_REGMAP_DUMMY) += regmap-dummy.o

1.7.11.3