media: v4l2-cci: Add support for little-endian encoded registers

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

Fixes: af73323b ("media: imx290: Convert to new CCI register access helpers")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[Sakari Ailus: Fixed commit message.]
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

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 = CCI_REG_WIDTH_BYTES(reg);
 	reg = CCI_REG_ADDR(reg);
 
@@ -40,15 +42,27 @@ int cci_read(struct regmap *map, u32 reg, u64 *val, int *err)
 		*val = buf[0];
 		break;
 	case 2:
+		if (little_endian)
+			*val = get_unaligned_le16(buf);
+		else
 			*val = get_unaligned_be16(buf);
 		break;
 	case 3:
+		if (little_endian)
+			*val = get_unaligned_le24(buf);
+		else
 			*val = get_unaligned_be24(buf);
 		break;
 	case 4:
+		if (little_endian)
+			*val = get_unaligned_le32(buf);
+		else
 			*val = get_unaligned_be32(buf);
 		break;
 	case 8:
+		if (little_endian)
+			*val = get_unaligned_le64(buf);
+		else
 			*val = get_unaligned_be64(buf);
 		break;
 	default:
@@ -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 = CCI_REG_WIDTH_BYTES(reg);
 	reg = CCI_REG_ADDR(reg);
 
@@ -83,15 +99,27 @@ int cci_write(struct regmap *map, u32 reg, u64 val, int *err)
 		buf[0] = val;
 		break;
 	case 2:
+		if (little_endian)
+			put_unaligned_le16(val, buf);
+		else
 			put_unaligned_be16(val, buf);
 		break;
 	case 3:
+		if (little_endian)
+			put_unaligned_le24(val, buf);
+		else
 			put_unaligned_be24(val, buf);
 		break;
 	case 4:
+		if (little_endian)
+			put_unaligned_le32(val, buf);
+		else
 			put_unaligned_be32(val, buf);
 		break;
 	case 8:
+		if (little_endian)
+			put_unaligned_le64(val, buf);
+		else
 			put_unaligned_be64(val, buf);
 		break;
 	default:

include/media/v4l2-cci.h

@@ -43,12 +43,17 @@ struct cci_reg_sequence {
 #define CCI_REG_WIDTH_BYTES(x)		FIELD_GET(CCI_REG_WIDTH_MASK, x)
 #define CCI_REG_WIDTH(x)		(CCI_REG_WIDTH_BYTES(x) << 3)
 #define CCI_REG_ADDR(x)			FIELD_GET(CCI_REG_ADDR_MASK, x)
+#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