[PATCH v3 1/2] media: v4l2-cci: Add support for little-endian encoded registers

[Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>]

Some sensors, e.g. Sony IMX290, are using little-endian registers. Add
support for those by encoding the endianess into Bit 20 of the register
address.

Fixes: af73323b97702 ("media: imx290: Convert to new CCI register access helpers")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
 drivers/media/v4l2-core/v4l2-cci.c | 44 ++++++++++++++++++++++++------
 include/media/v4l2-cci.h           |  5 ++++
 2 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-cci.c b/drivers/media/v4l2-core/v4l2-cci.c
index bc2dbec019b04..673637b67bf67 100644
--- a/drivers/media/v4l2-core/v4l2-cci.c
+++ b/drivers/media/v4l2-core/v4l2-cci.c
@@ -18,6 +18,7 @@
 
 int cci_read(struct regmap *map, u32 reg, u64 *val, int *err)
 {
+	bool little_endian;
 	unsigned int len;
 	u8 buf[8];
 	int ret;
@@ -25,6 +26,7 @@ int cci_read(struct regmap *map, u32 reg, u64 *val, int *err)
 	if (err && *err)
 		return *err;
 
+	little_endian = reg & CCI_REG_LE;
 	len = FIELD_GET(CCI_REG_WIDTH_MASK, reg);
 	reg = FIELD_GET(CCI_REG_ADDR_MASK, reg);
 
@@ -40,16 +42,28 @@ int cci_read(struct regmap *map, u32 reg, u64 *val, int *err)
 		*val = buf[0];
 		break;
 	case 2:
-		*val = get_unaligned_be16(buf);
+		if (little_endian)
+			*val = get_unaligned_le16(buf);
+		else
+			*val = get_unaligned_be16(buf);
 		break;
 	case 3:
-		*val = get_unaligned_be24(buf);
+		if (little_endian)
+			*val = get_unaligned_le24(buf);
+		else
+			*val = get_unaligned_be24(buf);
 		break;
 	case 4:
-		*val = get_unaligned_be32(buf);
+		if (little_endian)
+			*val = get_unaligned_le32(buf);
+		else
+			*val = get_unaligned_be32(buf);
 		break;
 	case 8:
-		*val = get_unaligned_be64(buf);
+		if (little_endian)
+			*val = get_unaligned_le64(buf);
+		else
+			*val = get_unaligned_be64(buf);
 		break;
 	default:
 		dev_err(regmap_get_device(map), "Error invalid reg-width %u for reg 0x%04x\n",
@@ -68,6 +82,7 @@ EXPORT_SYMBOL_GPL(cci_read);
 
 int cci_write(struct regmap *map, u32 reg, u64 val, int *err)
 {
+	bool little_endian;
 	unsigned int len;
 	u8 buf[8];
 	int ret;
@@ -75,6 +90,7 @@ int cci_write(struct regmap *map, u32 reg, u64 val, int *err)
 	if (err && *err)
 		return *err;
 
+	little_endian = reg & CCI_REG_LE;
 	len = FIELD_GET(CCI_REG_WIDTH_MASK, reg);
 	reg = FIELD_GET(CCI_REG_ADDR_MASK, reg);
 
@@ -83,16 +99,28 @@ int cci_write(struct regmap *map, u32 reg, u64 val, int *err)
 		buf[0] = val;
 		break;
 	case 2:
-		put_unaligned_be16(val, buf);
+		if (little_endian)
+			put_unaligned_le16(val, buf);
+		else
+			put_unaligned_be16(val, buf);
 		break;
 	case 3:
-		put_unaligned_be24(val, buf);
+		if (little_endian)
+			put_unaligned_le24(val, buf);
+		else
+			put_unaligned_be24(val, buf);
 		break;
 	case 4:
-		put_unaligned_be32(val, buf);
+		if (little_endian)
+			put_unaligned_le32(val, buf);
+		else
+			put_unaligned_be32(val, buf);
 		break;
 	case 8:
-		put_unaligned_be64(val, buf);
+		if (little_endian)
+			put_unaligned_le64(val, buf);
+		else
+			put_unaligned_be64(val, buf);
 		break;
 	default:
 		dev_err(regmap_get_device(map), "Error invalid reg-width %u for reg 0x%04x\n",
diff --git a/include/media/v4l2-cci.h b/include/media/v4l2-cci.h
index 0f6803e4b17e9..80cbb5cb70fa5 100644
--- a/include/media/v4l2-cci.h
+++ b/include/media/v4l2-cci.h
@@ -32,12 +32,17 @@ struct cci_reg_sequence {
 #define CCI_REG_ADDR_MASK		GENMASK(15, 0)
 #define CCI_REG_WIDTH_SHIFT		16
 #define CCI_REG_WIDTH_MASK		GENMASK(19, 16)
+#define CCI_REG_LE			BIT(20)
 
 #define CCI_REG8(x)			((1 << CCI_REG_WIDTH_SHIFT) | (x))
 #define CCI_REG16(x)			((2 << CCI_REG_WIDTH_SHIFT) | (x))
 #define CCI_REG24(x)			((3 << CCI_REG_WIDTH_SHIFT) | (x))
 #define CCI_REG32(x)			((4 << CCI_REG_WIDTH_SHIFT) | (x))
 #define CCI_REG64(x)			((8 << CCI_REG_WIDTH_SHIFT) | (x))
+#define CCI_REG16_LE(x)			(CCI_REG_LE | (2U << CCI_REG_WIDTH_SHIFT) | (x))
+#define CCI_REG24_LE(x)			(CCI_REG_LE | (3U << CCI_REG_WIDTH_SHIFT) | (x))
+#define CCI_REG32_LE(x)			(CCI_REG_LE | (4U << CCI_REG_WIDTH_SHIFT) | (x))
+#define CCI_REG64_LE(x)			(CCI_REG_LE | (8U << CCI_REG_WIDTH_SHIFT) | (x))
 
 /**
  * cci_read() - Read a value from a single CCI register
-- 
2.34.1