For the following cases of the SoCs using regmap-mmio:
Index CPU mode Device mode Need Bytes Swap ?
--------------------------------------------------
1 LE LE No
2 LE BE Yes
3 BE BE No
4 BE LE Yes
And possiblly one Device will be used in all the endianness modes
above with the same device driver, then for the 1 and 3 cases the
REGMAP_ENDIAN_NATIVE is okey, but for the 2 and 4 cases, the
REGMAP_ENDIAN_SWAP is needed.
For the DT node, just one property like 'endian-swap' will be okey
for cases 2 and 4.
----
Certainly, for the 2 case, we can just use REGMAP_ENDIAN_BIG
instead of REGMAP_ENDIAN_SWAP, and then we should add one DT node
property like 'big-endian'.
While for the 4 case, we can just use REGMAP_ENDIAN_LITTLE instead
of REGMAP_ENDIAN_SWAP, and then we should add one DT node property
like 'little-endian'. Another question is that the
REGMAP_ENDIAN_LITTLE hasn't support by regmap core yet.
And using the REGMAP_ENDIAN_BIG and REGMAP_ENDIAN_LITTLE will make
the driver a bit more complex, and also the usage of it.
Thus using the REGMAP_ENDIAN_SWAP and one DT node property like
'endian-swap' will make the driver more easy to develop and to use
for all the above possible cases.
Signed-off-by: Xiubo Li <li.xi...@freescale.com>
---
drivers/base/regmap/regmap.c | 56 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/regmap.h | 1 +
2 files changed, 57 insertions(+)
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 6a19515..71e0a0d 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -192,6 +192,14 @@ static void regmap_format_16_be(void *buf, unsigned int
val, unsigned int shift)
b[0] = cpu_to_be16(val << shift);
}
+static void regmap_format_16_swap(void *buf, unsigned int val,
+ unsigned int shift)
+{
+ __u16 *b = buf;
+
+ b[0] = __swab16(val << shift);
+}
+
static void regmap_format_16_native(void *buf, unsigned int val,
unsigned int shift)
{
@@ -216,6 +224,14 @@ static void regmap_format_32_be(void *buf, unsigned int
val, unsigned int shift)
b[0] = cpu_to_be32(val << shift);
}
+static void regmap_format_32_swap(void *buf, unsigned int val,
+ unsigned int shift)
+{
+ __u32 *b = buf;
+
+ b[0] = __swab32(val << shift);
+}
+
static void regmap_format_32_native(void *buf, unsigned int val,
unsigned int shift)
{
@@ -240,6 +256,13 @@ static unsigned int regmap_parse_16_be(const void *buf)
return be16_to_cpu(b[0]);
}
+static unsigned int regmap_parse_16_swap(const void *buf)
+{
+ const __u16 *b = buf;
+
+ return __swab16(b[0]);
+}
+
static void regmap_parse_16_be_inplace(void *buf)
{
__be16 *b = buf;
@@ -247,6 +270,13 @@ static void regmap_parse_16_be_inplace(void *buf)
b[0] = be16_to_cpu(b[0]);
}
+static void regmap_parse_16_swap_inplace(void *buf)
+{
+ __u16 *b = buf;
+
+ b[0] = __swab16(b[0]);
+}
+
static unsigned int regmap_parse_16_native(const void *buf)
{
return *(u16 *)buf;
@@ -269,6 +299,13 @@ static unsigned int regmap_parse_32_be(const void *buf)
return be32_to_cpu(b[0]);
}
+static unsigned int regmap_parse_32_swap(const void *buf)
+{
+ const __u32 *b = buf;
+
+ return __swab32((b[0]));
+}
+
static void regmap_parse_32_be_inplace(void *buf)
{
__be32 *b = buf;
@@ -276,6 +313,13 @@ static void regmap_parse_32_be_inplace(void *buf)
b[0] = be32_to_cpu(b[0]);
}
+static void regmap_parse_32_swap_inplace(void *buf)
+{
+ __u32 *b = buf;
+
+ b[0] = __swab32(b[0]);
+}
+
static unsigned int regmap_parse_32_native(const void *buf)
{
return *(u32 *)buf;
@@ -585,6 +629,12 @@ struct regmap *regmap_init(struct device *dev,
map->format.parse_val = regmap_parse_16_be;
map->format.parse_inplace = regmap_parse_16_be_inplace;
break;
+ case REGMAP_ENDIAN_SWAP:
+ map->format.format_val = regmap_format_16_swap;
+ map->format.parse_val = regmap_parse_16_swap;
+ map->format.parse_inplace =
+ regmap_parse_16_swap_inplace;
+ break;
case REGMAP_ENDIAN_NATIVE:
map->format.format_val = regmap_format_16_native;
map->format.parse_val = regmap_parse_16_native;
@@ -606,6 +656,12 @@ struct regmap *regmap_init(struct device *dev,
map->format.parse_val = regmap_parse_32_be;
map->format.parse_inplace = regmap_parse_32_be_inplace;
break;
+ case REGMAP_ENDIAN_SWAP:
+ map->format.format_val = regmap_format_32_swap;
+ map->format.parse_val = regmap_parse_32_swap;
+ map->format.parse_inplace =
+ regmap_parse_32_swap_inplace;
+ break;
case REGMAP_ENDIAN_NATIVE:
map->format.format_val = regmap_format_32_native;
map->format.parse_val = regmap_parse_32_native;
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 4149f1a..a2e68f3 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -56,6 +56,7 @@ enum regmap_endian {
REGMAP_ENDIAN_DEFAULT = 0,
REGMAP_ENDIAN_BIG,
REGMAP_ENDIAN_LITTLE,
+ REGMAP_ENDIAN_SWAP,
REGMAP_ENDIAN_NATIVE,
};
--
1.8.4
--
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