regmap: Add support for device specific write and read flag masks.

Some buses like SPI have no standard notation of read or write operations.
The general scheme here is to set or clear specific bits in the register
address to indicate whether the operation is a read or write. We already
support having a read flag mask per bus, but as there is no standard
the bits which need to be set or cleared differ between devices and vendors,
thus we need a mechanism to specify them per device.

This patch adds two new entries to the regmap_config struct, read_flag_mask and
write_flag_mask. These will be or'ed onto the top byte when doing a read or
write operation. If both masks are empty the device will fallback to the
regmap_bus masks.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

2 files changed, 15 insertions, 3 deletions

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 5ab3fef..7e14d5a 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -46,6 +46,9 @@ struct regmap {
 	bool (*readable_reg)(struct device *dev, unsigned int reg);
 	bool (*volatile_reg)(struct device *dev, unsigned int reg);
 	bool (*precious_reg)(struct device *dev, unsigned int reg);
+
+	u8 read_flag_mask;
+	u8 write_flag_mask;
 };
 
 bool regmap_writeable(struct regmap *map, unsigned int reg);
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 86b1847..e7adfe7 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -147,6 +147,13 @@ struct regmap *regmap_init(struct device *dev,
 	map->volatile_reg = config->volatile_reg;
 	map->precious_reg = config->precious_reg;
 
+	if (config->read_flag_mask || config->write_flag_mask) {
+		map->read_flag_mask = config->read_flag_mask;
+		map->write_flag_mask = config->write_flag_mask;
+	} else {
+		map->read_flag_mask = bus->read_flag_mask;
+	}
+
 	switch (config->reg_bits) {
 	case 4:
 		switch (config->val_bits) {
@@ -226,6 +233,7 @@ EXPORT_SYMBOL_GPL(regmap_exit);
 static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 			     const void *val, size_t val_len)
 {
+	u8 *u8 = map->work_buf;
 	void *buf;
 	int ret = -ENOTSUPP;
 	size_t len;
@@ -239,6 +247,8 @@ static int _regmap_raw_write(struct regmap *map, unsigned int reg,
 
 	map->format.format_reg(map->work_buf, reg);
 
+	u8[0] |= map->write_flag_mask;
+
 	trace_regmap_hw_write_start(map->dev, reg,
 				    val_len / map->format.val_bytes);
 
@@ -366,13 +376,12 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 	map->format.format_reg(map->work_buf, reg);
 
 	/*
-	 * Some buses flag reads by setting the high bits in the
+	 * Some buses or devices flag reads by setting the high bits in the
 	 * register addresss; since it's always the high bits for all
 	 * current formats we can do this here rather than in
 	 * formatting.  This may break if we get interesting formats.
 	 */
-	if (map->bus->read_flag_mask)
-		u8[0] |= map->bus->read_flag_mask;
+	u8[0] |= map->read_flag_mask;
 
 	trace_regmap_hw_read_start(map->dev, reg,
 				   val_len / map->format.val_bytes);