[PATCH v7 3/3] media: ov8856: Implement sensor module revision identification

Robert Foss
2020-05-05T10:02:14Z

Query the sensor for its module revision, and compare it
to known revisions.

Currently 2A and 1B revision indentification is supported.

Signed-off-by: Robert Foss <robert.foss@linaro.org>
---

- Changes since v3:
* Actually add module revision 2A

- Changes since v2:
* Add module revision 2A
* Sakari: Remove ov8856_check_revision()
* Sakari: Stop EEPROM streaming mode

drivers/media/i2c/ov8856.c | 53 ++++++++++++++++++++++++++++++++++++++
1 file changed, 53 insertions(+)

diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
index e6418a79801e..3c82c3e588d7 100644
--- a/drivers/media/i2c/ov8856.c
+++ b/drivers/media/i2c/ov8856.c
@@ -32,6 +32,19 @@
#define OV8856_MODE_STANDBY 0x00
#define OV8856_MODE_STREAMING 0x01

+/* module revisions */
+#define OV8856_2A_MODULE 0x01
+#define OV8856_1B_MODULE 0x02
+
+/* the OTP read-out buffer is at 0x7000 and 0xf is the offset
+ * of the byte in the OTP that means the module revision
+ */
+#define OV8856_MODULE_REVISION 0x700f
+#define OV8856_OTP_MODE_CTRL 0x3d84
+#define OV8856_OTP_LOAD_CTRL 0x3d81
+#define OV8856_OTP_MODE_AUTO 0x00
+#define OV8856_OTP_LOAD_CTRL_ENABLE BIT(0)
+
/* vertical-timings from sensor */
#define OV8856_REG_VTS 0x380e
#define OV8856_VTS_MAX 0x7fff
@@ -1152,6 +1165,46 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
return -ENXIO;
}

+ ret = ov8856_write_reg(ov8856, OV8856_REG_MODE_SELECT,
+ OV8856_REG_VALUE_08BIT, OV8856_MODE_STREAMING);
+ if (ret)
+ return ret;
+
+ ret = ov8856_write_reg(ov8856, OV8856_OTP_MODE_CTRL,
+ OV8856_REG_VALUE_08BIT, OV8856_OTP_MODE_AUTO);
+ if (ret) {
+ dev_err(&client->dev, "failed to set otp mode");
+ return ret;
+ }
+
+ ret = ov8856_write_reg(ov8856, OV8856_OTP_LOAD_CTRL,
+ OV8856_REG_VALUE_08BIT,
+ OV8856_OTP_LOAD_CTRL_ENABLE);
+ if (ret) {
+ dev_err(&client->dev, "failed to enable load control");
+ return ret;
+ }
+
+ ret = ov8856_read_reg(ov8856, OV8856_MODULE_REVISION,
+ OV8856_REG_VALUE_08BIT, &val);
+ if (ret) {
+ dev_err(&client->dev, "failed to read module revision");
+ return ret;
+ }
+
+ dev_info(&client->dev, "OV8856 revision %x (%s) at address 0x%02x\n",
+ val,
+ val == OV8856_2A_MODULE ? "2A" :
+ val == OV8856_1B_MODULE ? "1B" : "unknown revision",
+ client->addr);
+
+ ret = ov8856_write_reg(ov8856, OV8856_REG_MODE_SELECT,
+ OV8856_REG_VALUE_08BIT, OV8856_MODE_STANDBY);
+ if (ret) {
+ dev_err(&client->dev, "failed to exit streaming mode");
+ return ret;
+ }
+
return 0;
}

--
2.25.1