bus: sunxi-rsb: Add driver for Allwinner Reduced Serial Bus

Reduced Serial Bus (RSB) is an Allwinner proprietery interface
used to communicate with PMICs and other peripheral ICs.

RSB is a two-wire push-pull serial bus that supports 1 master
device and up to 15 active slave devices.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

drivers/bus/Kconfig

@@ -121,6 +121,17 @@ config SIMPLE_PM_BUS
 	  Controller (BSC, sometimes called "LBSC within Bus Bridge", or
 	  "External Bus Interface") as found on several Renesas ARM SoCs.
 
+config SUNXI_RSB
+	tristate "Allwinner sunXi Reduced Serial Bus Driver"
+	  default MACH_SUN8I || MACH_SUN9I
+	  depends on ARCH_SUNXI
+	  select REGMAP
+	  help
+	  Say y here to enable support for Allwinner's Reduced Serial Bus
+	  (RSB) support. This controller is responsible for communicating
+	  with various RSB based devices, such as AXP223, AXP8XX PMICs,
+	  and AC100/AC200 ICs.
+
 config VEXPRESS_CONFIG
 	bool "Versatile Express configuration bus"
 	default y if ARCH_VEXPRESS

drivers/bus/Makefile

@@ -15,5 +15,6 @@ obj-$(CONFIG_MVEBU_MBUS) 	+= mvebu-mbus.o
 obj-$(CONFIG_OMAP_INTERCONNECT)	+= omap_l3_smx.o omap_l3_noc.o
 
 obj-$(CONFIG_OMAP_OCP2SCP)	+= omap-ocp2scp.o
+obj-$(CONFIG_SUNXI_RSB)		+= sunxi-rsb.o
 obj-$(CONFIG_SIMPLE_PM_BUS)	+= simple-pm-bus.o
 obj-$(CONFIG_VEXPRESS_CONFIG)	+= vexpress-config.o

include/linux/sunxi-rsb.h

+/*
+ * Allwinner Reduced Serial Bus Driver
+ *
+ * Copyright (c) 2015 Chen-Yu Tsai
+ *
+ * Author: Chen-Yu Tsai <wens@csie.org>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#ifndef _SUNXI_RSB_H
+#define _SUNXI_RSB_H
+
+#include <linux/device.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+
+struct sunxi_rsb;
+
+/**
+ * struct sunxi_rsb_device - Basic representation of an RSB device
+ * @dev:	Driver model representation of the device.
+ * @ctrl:	RSB controller managing the bus hosting this device.
+ * @rtaddr:	This device's runtime address
+ * @hwaddr:	This device's hardware address
+ */
+struct sunxi_rsb_device {
+	struct device		dev;
+	struct sunxi_rsb	*rsb;
+	int			irq;
+	u8			rtaddr;
+	u16			hwaddr;
+};
+
+static inline struct sunxi_rsb_device *to_sunxi_rsb_device(struct device *d)
+{
+	return container_of(d, struct sunxi_rsb_device, dev);
+}
+
+static inline void *sunxi_rsb_device_get_drvdata(const struct sunxi_rsb_device *rdev)
+{
+	return dev_get_drvdata(&rdev->dev);
+}
+
+static inline void sunxi_rsb_device_set_drvdata(struct sunxi_rsb_device *rdev,
+						void *data)
+{
+	dev_set_drvdata(&rdev->dev, data);
+}
+
+/**
+ * struct sunxi_rsb_driver - RSB slave device driver
+ * @driver:	RSB device drivers should initialize name and owner field of
+ *		this structure.
+ * @probe:	binds this driver to a RSB device.
+ * @remove:	unbinds this driver from the RSB device.
+ */
+struct sunxi_rsb_driver {
+	struct device_driver driver;
+	int (*probe)(struct sunxi_rsb_device *rdev);
+	int (*remove)(struct sunxi_rsb_device *rdev);
+};
+
+static inline struct sunxi_rsb_driver *to_sunxi_rsb_driver(struct device_driver *d)
+{
+	return container_of(d, struct sunxi_rsb_driver, driver);
+}
+
+int sunxi_rsb_driver_register(struct sunxi_rsb_driver *rdrv);
+
+/**
+ * sunxi_rsb_driver_unregister() - unregister an RSB client driver
+ * @rdrv:	the driver to unregister
+ */
+static inline void sunxi_rsb_driver_unregister(struct sunxi_rsb_driver *rdrv)
+{
+	if (rdrv)
+		driver_unregister(&rdrv->driver);
+}
+
+#define module_sunxi_rsb_driver(__sunxi_rsb_driver) \
+	module_driver(__sunxi_rsb_driver, sunxi_rsb_driver_register, \
+			sunxi_rsb_driver_unregister)
+
+struct regmap *__devm_regmap_init_sunxi_rsb(struct sunxi_rsb_device *rdev,
+					    const struct regmap_config *config,
+					    struct lock_class_key *lock_key,
+					    const char *lock_name);
+
+/**
+ * devm_regmap_init_sunxi_rsb(): Initialise managed register map
+ *
+ * @rdev: Device that will be interacted with
+ * @config: Configuration for register map
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer
+ * to a struct regmap.  The regmap will be automatically freed by the
+ * device management code.
+ */
+#define devm_regmap_init_sunxi_rsb(rdev, config)			\
+	__regmap_lockdep_wrapper(__devm_regmap_init_sunxi_rsb, #config,	\
+				 rdev, config)
+
+#endif /* _SUNXI_RSB_H */