Hello Alexandru, thanks for your patch.
On Tue, Apr 02, 2024 at 01:59:24PM +0300, Alexandru Ardelean wrote:
> On some HW designs, it's easier for the layout if the P/N pins are swapped.
> In those cases, we need to adjust (for this) by configuring the MIPI analog
> registers differently. Specifically, register 0x3e needs to be 0xf6
> (instead of 0xd6).
>
> This change adds a 'lontium,pn-swap' device-tree property to configure the
> MIPI analog registers for P/N swap.
>
> Signed-off-by: Alexandru Ardelean <a...@shruggie.ro>
> ---
> drivers/gpu/drm/bridge/lontium-lt8912b.c | 25 +++++++++++++++++++++---
> 1 file changed, 22 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/lontium-lt8912b.c
> b/drivers/gpu/drm/bridge/lontium-lt8912b.c
> index 4b2ae27f0a57f..154126bb922b4 100644
> --- a/drivers/gpu/drm/bridge/lontium-lt8912b.c
> +++ b/drivers/gpu/drm/bridge/lontium-lt8912b.c
> @@ -47,6 +47,7 @@ struct lt8912 {
>
> u8 data_lanes;
> bool is_power_on;
> + bool do_pn_swap;
> };
>
> static int lt8912_write_init_config(struct lt8912 *lt)
> @@ -78,15 +79,31 @@ static int lt8912_write_init_config(struct lt8912 *lt)
> {0x55, 0x44},
> {0x57, 0x01},
> {0x5a, 0x02},
> -
> - /*MIPI Analog*/
> + };
> + const struct reg_sequence mipi_analog_seq[] = {
> {0x3e, 0xd6},
> {0x3f, 0xd4},
> {0x41, 0x3c},
> {0xB2, 0x00},
> };
> + const struct reg_sequence mipi_analog_pn_swap_seq[] = {
> + {0x3e, 0xf6},
> + {0x3f, 0xd4},
> + {0x41, 0x3c},
> + {0xB2, 0x00},
> + };
> + int ret;
>
> - return regmap_multi_reg_write(lt->regmap[I2C_MAIN], seq,
> ARRAY_SIZE(seq));
> + ret = regmap_multi_reg_write(lt->regmap[I2C_MAIN], seq,
> ARRAY_SIZE(seq));
> + if (ret < 0)
> + return ret;
> +
> + if (!lt->do_pn_swap)
> + return regmap_multi_reg_write(lt->regmap[I2C_MAIN],
> mipi_analog_seq,
> + ARRAY_SIZE(mipi_analog_seq));
> +
> + return regmap_multi_reg_write(lt->regmap[I2C_MAIN],
> mipi_analog_pn_swap_seq,
> + ARRAY_SIZE(mipi_analog_pn_swap_seq));
Can you just remove {0x3e, 0xd6} from the register/value array and write
it afterward depending on `do_pn_swap` value? Or keep it with the
current value and only overwrite it when do_pn_swap is true?
If you do it this way is a 4 line change.
> static int lt8912_write_mipi_basic_config(struct lt8912 *lt)
> @@ -702,6 +719,8 @@ static int lt8912_parse_dt(struct lt8912 *lt)
> }
> lt->gp_reset = gp_reset;
>
> + lt->do_pn_swap = device_property_read_bool(dev, "lontium,pn-swap");
I would call this variable the same that is called in the lontium
documentation, mipirx_diff_swap
Francesco
