(This patch is in prototype stage)
This adds SCCB helper functions (sccb_read_byte and sccb_write_byte) that
are intended to be used by some of Omnivision sensor drivers.
The ov772x driver is going to use these functions in order to make it work
with most i2c controllers.
As the ov772x device doesn't support repeated starts, this driver currently
requires I2C_FUNC_PROTOCOL_MANGLING that is not supported by many i2c
controller drivers.
With the sccb_read_byte() that issues two separated requests in order to
avoid repeated start, the driver doesn't require I2C_FUNC_PROTOCOL_MANGLING.
Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Cc: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Hans Verkuil <hans.verkuil@xxxxxxxxx>
Cc: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxxx>
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
---
drivers/media/i2c/Kconfig | 4 ++++
drivers/media/i2c/Makefile | 1 +
drivers/media/i2c/sccb.c | 35 +++++++++++++++++++++++++++++++++++
drivers/media/i2c/sccb.h | 14 ++++++++++++++
4 files changed, 54 insertions(+)
create mode 100644 drivers/media/i2c/sccb.c
create mode 100644 drivers/media/i2c/sccb.h
diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
index 541f0d28..19e5601 100644
--- a/drivers/media/i2c/Kconfig
+++ b/drivers/media/i2c/Kconfig
@@ -569,6 +569,9 @@ config VIDEO_THS8200
comment "Camera sensor devices"
+config SCCB
+ bool
+
config VIDEO_APTINA_PLL
tristate
@@ -692,6 +695,7 @@ config VIDEO_OV772X
tristate "OmniVision OV772x sensor support"
depends on I2C && VIDEO_V4L2
depends on MEDIA_CAMERA_SUPPORT
+ select SCCB
---help---
This is a Video4Linux2 sensor-level driver for the OmniVision
OV772x camera.
diff --git a/drivers/media/i2c/Makefile b/drivers/media/i2c/Makefile
index ea34aee..82fbd78 100644
--- a/drivers/media/i2c/Makefile
+++ b/drivers/media/i2c/Makefile
@@ -62,6 +62,7 @@ obj-$(CONFIG_VIDEO_VP27SMPX) += vp27smpx.o
obj-$(CONFIG_VIDEO_SONY_BTF_MPX) += sony-btf-mpx.o
obj-$(CONFIG_VIDEO_UPD64031A) += upd64031a.o
obj-$(CONFIG_VIDEO_UPD64083) += upd64083.o
+obj-$(CONFIG_SCCB) += sccb.o
obj-$(CONFIG_VIDEO_OV2640) += ov2640.o
obj-$(CONFIG_VIDEO_OV2685) += ov2685.o
obj-$(CONFIG_VIDEO_OV5640) += ov5640.o
diff --git a/drivers/media/i2c/sccb.c b/drivers/media/i2c/sccb.c
new file mode 100644
index 0000000..80a3fb7
--- /dev/null
+++ b/drivers/media/i2c/sccb.c
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/i2c.h>
+
+int sccb_read_byte(struct i2c_client *client, u8 addr)
+{
+ int ret;
+ u8 val;
+
+ /* Issue two separated requests in order to avoid repeated start */
+
+ ret = i2c_master_send(client, &addr, 1);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_master_recv(client, &val, 1);
+ if (ret < 0)
+ return ret;
+
+ return val;
+}
+EXPORT_SYMBOL_GPL(sccb_read_byte);
+
+int sccb_write_byte(struct i2c_client *client, u8 addr, u8 data)
+{
+ int ret;
+ unsigned char msgbuf[] = { addr, data };
+
+ ret = i2c_master_send(client, msgbuf, 2);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(sccb_write_byte);
diff --git a/drivers/media/i2c/sccb.h b/drivers/media/i2c/sccb.h
new file mode 100644
index 0000000..68da0e9
--- /dev/null
+++ b/drivers/media/i2c/sccb.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * SCCB helper functions
+ */
+
+#ifndef __SCCB_H__
+#define __SCCB_H__
+
+#include <linux/i2c.h>
+
+int sccb_read_byte(struct i2c_client *client, u8 addr);
+int sccb_write_byte(struct i2c_client *client, u8 addr, u8 data);
+
+#endif /* __SCCB_H__ */
--
2.7.4
