media: ov8856: Implement sensor module revision identification

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

Currently 2A and 1B revision indentification is supported.

[Sakari Ailus: Wrap a line over 80, alignment, use %u for printing u32]

Signed-off-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
index efc3e23..4ca2767 100644 (file)
--- 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
@@ -1156,6 +1169,46 @@ 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;
 }