ARM: prima2: move to use REGMAP APIs for rtciobrg

all devices behind rtciobrg needs a special way to access. currently they
are using a platform-specific API.
this patch moves to REGMAP, then clients can use regmap APIs to read/write.
for the moment, old APIs are still kept, once all clients move to regmap,
old APIs will be dropped.

this patch also does minor clean for comments, authors statement.

Signed-off-by: Guo Zeng <[e-mail]>
Signed-off-by: Barry Song <[e-mail]>

arch/arm/mach-prima2/Kconfig

···
 	select ARCH_REQUIRE_GPIOLIB
 	select GENERIC_IRQ_CHIP
 	select NO_IOPORT_MAP
+	select REGMAP
 	select PINCTRL
 	select PINCTRL_SIRF
 	help

arch/arm/mach-prima2/rtciobrg.c

···
 /*
- * RTC I/O Bridge interfaces for CSR SiRFprimaII
+ * RTC I/O Bridge interfaces for CSR SiRFprimaII/atlas7
  * ARM access the registers of SYSRTC, GPSRTC and PWRC through this module
  *
  * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
···
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/io.h>
+#include <linux/regmap.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
···
 {
 	unsigned long flags, val;
 
+	/* TODO: add hwspinlock to sync with M3 */
 	spin_lock_irqsave(&rtciobrg_lock, flags);
 
 	val = __sirfsoc_rtc_iobrg_readl(addr);
···
 {
 	unsigned long flags;
 
+	 /* TODO: add hwspinlock to sync with M3 */
 	spin_lock_irqsave(&rtciobrg_lock, flags);
 
 	sirfsoc_rtc_iobrg_pre_writel(val, addr);
···
 	spin_unlock_irqrestore(&rtciobrg_lock, flags);
 }
 EXPORT_SYMBOL_GPL(sirfsoc_rtc_iobrg_writel);
+
+
+static int regmap_iobg_regwrite(void *context, unsigned int reg,
+				   unsigned int val)
+{
+	sirfsoc_rtc_iobrg_writel(val, reg);
+	return 0;
+}
+
+static int regmap_iobg_regread(void *context, unsigned int reg,
+				  unsigned int *val)
+{
+	*val = (u32)sirfsoc_rtc_iobrg_readl(reg);
+	return 0;
+}
+
+static struct regmap_bus regmap_iobg = {
+	.reg_write = regmap_iobg_regwrite,
+	.reg_read = regmap_iobg_regread,
+};
+
+/**
+ * devm_regmap_init_iobg(): Initialise managed register map
+ *
+ * @iobg: 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.
+ */
+struct regmap *devm_regmap_init_iobg(struct device *dev,
+				    const struct regmap_config *config)
+{
+	const struct regmap_bus *bus = &regmap_iobg;
+
+	return devm_regmap_init(dev, bus, dev, config);
+}
+EXPORT_SYMBOL_GPL(devm_regmap_init_iobg);
 
 static const struct of_device_id rtciobrg_ids[] = {
 	{ .compatible = "sirf,prima2-rtciobg" },
···
 }
 postcore_initcall(sirfsoc_rtciobrg_init);
 
-MODULE_AUTHOR("Zhiwu Song <[e-mail]>, "
-		"Barry Song <[e-mail]>");
+MODULE_AUTHOR("Zhiwu Song <[e-mail]>");
+MODULE_AUTHOR("Barry Song <[e-mail]>");
 MODULE_DESCRIPTION("CSR SiRFprimaII rtc io bridge");
 MODULE_LICENSE("GPL v2");

include/linux/rtc/sirfsoc_rtciobrg.h

···
 #ifndef _SIRFSOC_RTC_IOBRG_H_
 #define _SIRFSOC_RTC_IOBRG_H_
 
+struct regmap_config;
+
 extern void sirfsoc_rtc_iobrg_besyncing(void);
 
 extern u32 sirfsoc_rtc_iobrg_readl(u32 addr);
 
 extern void sirfsoc_rtc_iobrg_writel(u32 val, u32 addr);
+struct regmap *devm_regmap_init_iobg(struct device *dev,
+				    const struct regmap_config *config);
 
 #endif