regmap: Updates for v3.18

The main update this time around is the addition of a standard DT
 binding for specifying the endianness of devices.  This allows drivers
 to support any endianness of device register map without any code,
 useful for configurable IP blocks.
 
 There's also a few bug fixes that I didn't get round to sending, none of
 them terribly severe or new, and a reduction in size for struct regmap.
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Merge tag 'regmap-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap

Pull regmap updates from Mark Brown:
 "The main update this time around is the addition of a standard DT
  binding for specifying the endianness of devices.  This allows drivers
  to support any endianness of device register map without any code,
  useful for configurable IP blocks.

  There's also a few bug fixes that I didn't get round to sending, none
  of them terribly severe or new, and a reduction in size for struct
  regmap"

* tag 'regmap-v3.18' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap:
  regmap: Fix debugfs-file 'registers' mode
  regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.
  regmap: debugfs: fix possbile NULL pointer dereference
  regmap: fix NULL pointer dereference in _regmap_write/read
  regmap: fix NULL pointer dereference in regmap_get_val_endian
  regmap: cache: Do not fail silently from regcache_sync calls
  regmap: change struct regmap's internal locks as union
  regmap: Split regmap_get_endian() in two functions
  regmap: of_regmap_get_endian() cleanup
  regmap: Fix DT endianess parsing logic
  regmap: Add explicit dependencies to catch "select" misuse
  regmap: Restore L: linux-kernel@vger.kernel.org entry
  regmap: Add the DT binding documentation for endianness
  regmap: add DT endianness binding support.

Documentation/devicetree/bindings/regmap/regmap.txt

@@ -0,0 +1,47 @@
+Device-Tree binding for regmap
+
+The endianness mode of CPU & Device scenarios:
+Index     Device     Endianness properties
+---------------------------------------------------
+1         BE         'big-endian'
+2         LE         'little-endian'
+
+For one device driver, which will run in different scenarios above
+on different SoCs using the devicetree, we need one way to simplify
+this.
+
+Required properties:
+- {big,little}-endian: these are boolean properties, if absent
+  meaning that the CPU and the Device are in the same endianness mode,
+  these properties are for register values and all the buffers only.
+
+Examples:
+Scenario 1 : CPU in LE mode & device in LE mode.
+dev: dev@40031000 {
+	      compatible = "name";
+	      reg = <0x40031000 0x1000>;
+	      ...
+};
+
+Scenario 2 : CPU in LE mode & device in BE mode.
+dev: dev@40031000 {
+	      compatible = "name";
+	      reg = <0x40031000 0x1000>;
+	      ...
+	      big-endian;
+};
+
+Scenario 3 : CPU in BE mode & device in BE mode.
+dev: dev@40031000 {
+	      compatible = "name";
+	      reg = <0x40031000 0x1000>;
+	      ...
+};
+
+Scenario 4 : CPU in BE mode & device in LE mode.
+dev: dev@40031000 {
+	      compatible = "name";
+	      reg = <0x40031000 0x1000>;
+	      ...
+	      little-endian;
+};

MAINTAINERS

@@ -7595,6 +7595,7 @@ F:	fs/reiserfs/
 
 REGISTER MAP ABSTRACTION
 M:	Mark Brown <broonie@kernel.org>
+L:	linux-kernel@vger.kernel.org
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git
 S:	Supported
 F:	drivers/base/regmap/

drivers/base/regmap/Kconfig

@@ -11,12 +11,15 @@ config REGMAP
 
 config REGMAP_I2C
 	tristate
+	depends on I2C
 
 config REGMAP_SPI
 	tristate
+	depends on SPI
 
 config REGMAP_SPMI
 	tristate
+	depends on SPMI
 
 config REGMAP_MMIO
 	tristate

drivers/base/regmap/internal.h

@@ -49,8 +49,10 @@ struct regmap_async {
 };
 
 struct regmap {
-	struct mutex mutex;
-	spinlock_t spinlock;
+	union {
+		struct mutex mutex;
+		spinlock_t spinlock;
+	};
 	unsigned long spinlock_flags;
 	regmap_lock lock;
 	regmap_unlock unlock;

drivers/base/regmap/regcache.c

@@ -269,8 +269,11 @@ static int regcache_default_sync(struct regmap *map, unsigned int min,
 		map->cache_bypass = 1;
 		ret = _regmap_write(map, reg, val);
 		map->cache_bypass = 0;
-		if (ret)
+		if (ret) {
+			dev_err(map->dev, "Unable to sync register %#x. %d\n",
+				reg, ret);
 			return ret;
+		}
 		dev_dbg(map->dev, "Synced register %#x, value %#x\n", reg, val);
 	}
 
@@ -615,8 +618,11 @@ static int regcache_sync_block_single(struct regmap *map, void *block,
 		ret = _regmap_write(map, regtmp, val);
 
 		map->cache_bypass = 0;
-		if (ret != 0)
+		if (ret != 0) {
+			dev_err(map->dev, "Unable to sync register %#x. %d\n",
+				regtmp, ret);
 			return ret;
+		}
 		dev_dbg(map->dev, "Synced register %#x, value %#x\n",
 			regtmp, val);
 	}
@@ -641,6 +647,9 @@ static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
 	map->cache_bypass = 1;
 
 	ret = _regmap_raw_write(map, base, *data, count * val_bytes);
+	if (ret)
+		dev_err(map->dev, "Unable to sync registers %#x-%#x. %d\n",
+			base, cur - map->reg_stride, ret);
 
 	map->cache_bypass = 0;
 

drivers/base/regmap/regmap-debugfs.c

@@ -473,6 +473,7 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
 {
 	struct rb_node *next;
 	struct regmap_range_node *range_node;
+	const char *devname = "dummy";
 
 	/* If we don't have the debugfs root yet, postpone init */
 	if (!regmap_debugfs_root) {
@@ -491,12 +492,15 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
 	INIT_LIST_HEAD(&map->debugfs_off_cache);
 	mutex_init(&map->cache_lock);
 
+	if (map->dev)
+		devname = dev_name(map->dev);
+
 	if (name) {
 		map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
-					      dev_name(map->dev), name);
+					      devname, name);
 		name = map->debugfs_name;
 	} else {
-		name = dev_name(map->dev);
+		name = devname;
 	}
 
 	map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);

drivers/base/regmap/regmap-i2c.c

@@ -168,6 +168,8 @@ static struct regmap_bus regmap_i2c = {
 	.write = regmap_i2c_write,
 	.gather_write = regmap_i2c_gather_write,
 	.read = regmap_i2c_read,
+	.reg_format_endian_default = REGMAP_ENDIAN_BIG,
+	.val_format_endian_default = REGMAP_ENDIAN_BIG,
 };
 
 static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,

drivers/base/regmap/regmap-spi.c

@@ -109,6 +109,8 @@ static struct regmap_bus regmap_spi = {
 	.async_alloc = regmap_spi_async_alloc,
 	.read = regmap_spi_read,
 	.read_flag_mask = 0x80,
+	.reg_format_endian_default = REGMAP_ENDIAN_BIG,
+	.val_format_endian_default = REGMAP_ENDIAN_BIG,
 };
 
 /**

drivers/base/regmap/regmap.c

@@ -15,6 +15,7 @@
 #include <linux/export.h>
 #include <linux/mutex.h>
 #include <linux/err.h>
+#include <linux/of.h>
 #include <linux/rbtree.h>
 #include <linux/sched.h>
 
@@ -448,6 +449,71 @@ int regmap_attach_dev(struct device *dev, struct regmap *map,
 }
 EXPORT_SYMBOL_GPL(regmap_attach_dev);
 
+static enum regmap_endian regmap_get_reg_endian(const struct regmap_bus *bus,
+					const struct regmap_config *config)
+{
+	enum regmap_endian endian;
+
+	/* Retrieve the endianness specification from the regmap config */
+	endian = config->reg_format_endian;
+
+	/* If the regmap config specified a non-default value, use that */
+	if (endian != REGMAP_ENDIAN_DEFAULT)
+		return endian;
+
+	/* Retrieve the endianness specification from the bus config */
+	if (bus && bus->reg_format_endian_default)
+		endian = bus->reg_format_endian_default;
+
+	/* If the bus specified a non-default value, use that */
+	if (endian != REGMAP_ENDIAN_DEFAULT)
+		return endian;
+
+	/* Use this if no other value was found */
+	return REGMAP_ENDIAN_BIG;
+}
+
+static enum regmap_endian regmap_get_val_endian(struct device *dev,
+					const struct regmap_bus *bus,
+					const struct regmap_config *config)
+{
+	struct device_node *np;
+	enum regmap_endian endian;
+
+	/* Retrieve the endianness specification from the regmap config */
+	endian = config->val_format_endian;
+
+	/* If the regmap config specified a non-default value, use that */
+	if (endian != REGMAP_ENDIAN_DEFAULT)
+		return endian;
+
+	/* If the dev and dev->of_node exist try to get endianness from DT */
+	if (dev && dev->of_node) {
+		np = dev->of_node;
+
+		/* Parse the device's DT node for an endianness specification */
+		if (of_property_read_bool(np, "big-endian"))
+			endian = REGMAP_ENDIAN_BIG;
+		else if (of_property_read_bool(np, "little-endian"))
+			endian = REGMAP_ENDIAN_LITTLE;
+
+		/* If the endianness was specified in DT, use that */
+		if (endian != REGMAP_ENDIAN_DEFAULT)
+			return endian;
+	}
+
+	/* Retrieve the endianness specification from the bus config */
+	if (bus && bus->val_format_endian_default)
+		endian = bus->val_format_endian_default;
+
+	/* If the bus specified a non-default value, use that */
+	if (endian != REGMAP_ENDIAN_DEFAULT)
+		return endian;
+
+	/* Use this if no other value was found */
+	return REGMAP_ENDIAN_BIG;
+}
+
 /**
  * regmap_init(): Initialise register map
  *
@@ -551,17 +617,8 @@ struct regmap *regmap_init(struct device *dev,
 		map->reg_read  = _regmap_bus_read;
 	}
 
-	reg_endian = config->reg_format_endian;
-	if (reg_endian == REGMAP_ENDIAN_DEFAULT)
-		reg_endian = bus->reg_format_endian_default;
-	if (reg_endian == REGMAP_ENDIAN_DEFAULT)
-		reg_endian = REGMAP_ENDIAN_BIG;
-
-	val_endian = config->val_format_endian;
-	if (val_endian == REGMAP_ENDIAN_DEFAULT)
-		val_endian = bus->val_format_endian_default;
-	if (val_endian == REGMAP_ENDIAN_DEFAULT)
-		val_endian = REGMAP_ENDIAN_BIG;
+	reg_endian = regmap_get_reg_endian(bus, config);
+	val_endian = regmap_get_val_endian(dev, bus, config);
 
 	switch (config->reg_bits + map->reg_shift) {
 	case 2:
@@ -1408,7 +1465,7 @@ int _regmap_write(struct regmap *map, unsigned int reg,
 	}
 
 #ifdef LOG_DEVICE
-	if (strcmp(dev_name(map->dev), LOG_DEVICE) == 0)
+	if (map->dev && strcmp(dev_name(map->dev), LOG_DEVICE) == 0)
 		dev_info(map->dev, "%x <= %x\n", reg, val);
 #endif
 
@@ -1659,6 +1716,9 @@ out:
 	} else {
 		void *wval;
 
+		if (!val_count)
+			return -EINVAL;
+
 		wval = kmemdup(val, val_count * val_bytes, GFP_KERNEL);
 		if (!wval) {
 			dev_err(map->dev, "Error in memory allocation\n");
@@ -2058,7 +2118,7 @@ static int _regmap_read(struct regmap *map, unsigned int reg,
 	ret = map->reg_read(context, reg, val);
 	if (ret == 0) {
 #ifdef LOG_DEVICE
-		if (strcmp(dev_name(map->dev), LOG_DEVICE) == 0)
+		if (map->dev && strcmp(dev_name(map->dev), LOG_DEVICE) == 0)
 			dev_info(map->dev, "%x => %x\n", reg, *val);
 #endif