Re: [PATCH v2 2/2] media: i2c: adv7180: fix adv7280 BT.656-4 compatibility

From: Matthew Michilot <redacted>

Captured video would be out of sync when using the adv7280 with
the BT.656-4 protocol. Certain registers (0x04, 0x31, 0xE6) had to
be configured properly to ensure BT.656-4 compatibility.

An error in the adv7280 reference manual suggested that EAV/SAV mode
was enabled by default, however upon inspecting register 0x31, it was
determined to be disabled by default.

Signed-off-by: Matthew Michilot <redacted>
Reviewed-by: Tim Harvey <tharvey@gateworks.com>
[fabio: Introduce "adv,force-bt656-4" to not affect the existing users]
Signed-off-by: Fabio Estevam <festevam@gmail.com>
---
Changes since v1:
- Remove the part number from the property name (Rob)

 drivers/media/i2c/adv7180.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/media/i2c/adv7180.c b/drivers/media/i2c/adv7180.c
index 44bb6fe85644..a532df813d74 100644
--- a/drivers/media/i2c/adv7180.c
+++ b/drivers/media/i2c/adv7180.c

@@ -94,6 +94,7 @@
 #define ADV7180_REG_SHAP_FILTER_CTL_1  0x0017
 #define ADV7180_REG_CTRL_2             0x001d
 #define ADV7180_REG_VSYNC_FIELD_CTL_1  0x0031
+#define ADV7180_VSYNC_FIELD_CTL_1_NEWAV 0x12
 #define ADV7180_REG_MANUAL_WIN_CTL_1   0x003d
 #define ADV7180_REG_MANUAL_WIN_CTL_2   0x003e
 #define ADV7180_REG_MANUAL_WIN_CTL_3   0x003f

@@ -216,6 +217,7 @@ struct adv7180_state {
        struct i2c_client       *vpp_client;
        const struct adv7180_chip_info *chip_info;
        enum v4l2_field         field;
+       bool                    force_bt656_4;
 };
 #define to_adv7180_sd(_ctrl) (&container_of(_ctrl->handler,            \
                                            struct adv7180_state,       \

@@ -963,10 +965,26 @@ static int adv7182_init(struct adv7180_state *state)
                adv7180_write(state, ADV7180_REG_EXTENDED_OUTPUT_CONTROL, 0x57);
                adv7180_write(state, ADV7180_REG_CTRL_2, 0xc0);
        } else {
-               if (state->chip_info->flags & ADV7180_FLAG_V2)
-                       adv7180_write(state,
-                                     ADV7180_REG_EXTENDED_OUTPUT_CONTROL,
-                                     0x17);
+               if (state->chip_info->flags & ADV7180_FLAG_V2) {
+                       if (state->force_bt656_4) {
+                               /* ITU-R BT.656-4 compatible */
+                               adv7180_write(state,
+                                             ADV7180_REG_EXTENDED_OUTPUT_CONTROL,
+                                             ADV7180_EXTENDED_OUTPUT_CONTROL_NTSCDIS);
+                               /* Manually set NEWAVMODE */
+                               adv7180_write(state,
+                                             ADV7180_REG_VSYNC_FIELD_CTL_1,
+                                             ADV7180_VSYNC_FIELD_CTL_1_NEWAV);
+                               /* Manually set V bit end position in NTSC mode */
+                               adv7180_write(state,
+                                            ADV7180_REG_NTSC_V_BIT_END,
+                                            ADV7180_NTSC_V_BIT_END_MANUAL_NVEND);
+                       } else {
+                               adv7180_write(state,
+                                             ADV7180_REG_EXTENDED_OUTPUT_CONTROL,
+                                             0x17);
+                       }
+               }
                else
                        adv7180_write(state,
                                      ADV7180_REG_EXTENDED_OUTPUT_CONTROL,

@@ -1314,6 +1332,7 @@ static int init_device(struct adv7180_state *state)
 static int adv7180_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
 {
+       struct device_node *np = client->dev.of_node;
        struct adv7180_state *state;
        struct v4l2_subdev *sd;
        int ret;

@@ -1338,6 +1357,9 @@ static int adv7180_probe(struct i2c_client *client,
                return ret;
        }

+       if (of_property_read_bool(np, "adv,force-bt656-4"))
+               state->force_bt656_4 = true;
+
        if (state->chip_info->flags & ADV7180_FLAG_MIPI_CSI2) {
                state->csi_client = i2c_new_dummy_device(client->adapter,
                                ADV7180_DEFAULT_CSI_I2C_ADDR);
--

2.25.1