regmap: Allow longer flag masks for read and write

We currently only support masking the top bit for read and write
flags. Let's make the mask unsigned long and mask the bytes based
on the configured register length to make things more generic.

This allows using regmap for more exotic combinations like SPI
devices that need little endian addressing.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/internal.h

@@ -105,8 +105,8 @@ struct regmap {
 
 	bool defer_caching;
 
-	u8 read_flag_mask;
-	u8 write_flag_mask;
+	unsigned long read_flag_mask;
+	unsigned long write_flag_mask;
 
 	/* number of bits to (left) shift the reg value when formatting*/
 	int reg_shift;

drivers/base/regmap/regmap.c

@@ -1296,12 +1296,26 @@ static int _regmap_select_page(struct regmap *map, unsigned int *reg,
 	return 0;
 }
 
+static void regmap_set_work_buf_flag_mask(struct regmap *map, int max_bytes,
+					  unsigned long mask)
+{
+	u8 *buf;
+	int i;
+
+	if (!mask || !map->work_buf)
+		return;
+
+	buf = map->work_buf;
+
+	for (i = 0; i < max_bytes; i++)
+		buf[i] |= (mask >> (8 * i)) & 0xff;
+}
+
 int _regmap_raw_write(struct regmap *map, unsigned int reg,
 		      const void *val, size_t val_len)
 {
 	struct regmap_range_node *range;
 	unsigned long flags;
-	u8 *u8 = map->work_buf;
 	void *work_val = map->work_buf + map->format.reg_bytes +
 		map->format.pad_bytes;
 	void *buf;
@@ -1370,8 +1384,8 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
 	}
 
 	map->format.format_reg(map->work_buf, reg, map->reg_shift);
-
-	u8[0] |= map->write_flag_mask;
+	regmap_set_work_buf_flag_mask(map, map->format.reg_bytes,
+				      map->write_flag_mask);
 
 	/*
 	 * Essentially all I/O mechanisms will be faster with a single
@@ -2245,7 +2259,6 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 			    unsigned int val_len)
 {
 	struct regmap_range_node *range;
-	u8 *u8 = map->work_buf;
 	int ret;
 
 	WARN_ON(!map->bus);
@@ -2262,15 +2275,8 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 	}
 
 	map->format.format_reg(map->work_buf, reg, map->reg_shift);
-
-	/*
-	 * Some buses or devices flag reads by setting the high bits in the
-	 * register address; 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.
-	 */
-	u8[0] |= map->read_flag_mask;
-
+	regmap_set_work_buf_flag_mask(map, map->format.reg_bytes,
+				      map->read_flag_mask);
 	trace_regmap_hw_read_start(map, reg, val_len / map->format.val_bytes);
 
 	ret = map->bus->read(map->bus_context, map->work_buf,

include/linux/regmap.h

@@ -241,9 +241,9 @@ typedef void (*regmap_unlock)(void *);
  *                register cache support).
  * @num_reg_defaults: Number of elements in reg_defaults.
  *
- * @read_flag_mask: Mask to be set in the top byte of the register when doing
+ * @read_flag_mask: Mask to be set in the top bytes of the register when doing
  *                  a read.
- * @write_flag_mask: Mask to be set in the top byte of the register when doing
+ * @write_flag_mask: Mask to be set in the top bytes of the register when doing
  *                   a write. If both read_flag_mask and write_flag_mask are
  *                   empty the regmap_bus default masks are used.
  * @use_single_rw: If set, converts the bulk read and write operations into
@@ -299,8 +299,8 @@ struct regmap_config {
 	const void *reg_defaults_raw;
 	unsigned int num_reg_defaults_raw;
 
-	u8 read_flag_mask;
-	u8 write_flag_mask;
+	unsigned long read_flag_mask;
+	unsigned long write_flag_mask;
 
 	bool use_single_rw;
 	bool can_multi_write;