Re: [PATCH v10 18/19] drm/vc4: vec: Add support for more analog TV standards

From: Mauro Carvalho Chehab
Date: Thu Nov 17 2022 - 10:49:49 EST

On Thu, 17 Nov 2022 10:29:01 +0100
Maxime Ripard <maxime@xxxxxxxxxx> wrote:

> From: Mateusz Kwiatkowski <kfyatek+publicgit@xxxxxxxxx>
>
> Add support for the following composite output modes (all of them are
> somewhat more obscure than the previously defined ones):
>
> - NTSC_443 - NTSC-style signal with the chroma subcarrier shifted to
> 4.43361875 MHz (the PAL subcarrier frequency). Never used for
> broadcasting, but sometimes used as a hack to play NTSC content in PAL
> regions (e.g. on VCRs).

> - PAL_N - PAL with alternative chroma subcarrier frequency,
> 3.58205625 MHz. Used as a broadcast standard in Argentina, Paraguay
> and Uruguay to fit 576i50 with colour in 6 MHz channel raster.

That's not right. Argentina uses a different standard than Paraguay and
Uruguai.

See, there are two variants of PAL/N. The original one and PAL/N' - also
called PAL/NC or PAL/CN (Combination N). Some of the timings are
different on /NC variant.

As far as I'm aware, PAL/Nc is used in Argentina, while
PAL/N is used in Paraguai and Uruguai, but I may be wrong on that,
as it has been a long time since had to touch on this.

> - PAL60 - 480i60 signal with PAL-style color at normal European PAL
> frequency. Another non-standard, non-broadcast mode, used in similar
> contexts as NTSC_443. Some displays support one but not the other.

> - SECAM - French frequency-modulated analog color standard; also have
> been broadcast in Eastern Europe and various parts of Africa and Asia.
> Uses the same 576i50 timings as PAL.

This is also wrong. just like PAL, there are several variants of SECAM,
one used in France, and a different one in France overseas and on
previous France colonies in Africa and Asia. Eastern Europe also used
different variants of SECAM.

>
> Also added some comments explaining color subcarrier frequency
> registers.
>
> Acked-by: Noralf Trønnes <noralf@xxxxxxxxxxx>
> Signed-off-by: Mateusz Kwiatkowski <kfyatek+publicgit@xxxxxxxxx>
> Tested-by: Mateusz Kwiatkowski <kfyatek+publicgit@xxxxxxxxx>
> Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
>
> ---
> Changes in v6:
> - Support PAL60 again
> ---
> drivers/gpu/drm/vc4/vc4_vec.c | 111 ++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 107 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_vec.c b/drivers/gpu/drm/vc4/vc4_vec.c
> index a828fc6fb776..d23dbad3cbf6 100644
> --- a/drivers/gpu/drm/vc4/vc4_vec.c
> +++ b/drivers/gpu/drm/vc4/vc4_vec.c
> @@ -46,6 +46,7 @@
> #define VEC_CONFIG0_YDEL(x) ((x) << 26)
> #define VEC_CONFIG0_CDEL_MASK GENMASK(25, 24)
> #define VEC_CONFIG0_CDEL(x) ((x) << 24)
> +#define VEC_CONFIG0_SECAM_STD BIT(21)
> #define VEC_CONFIG0_PBPR_FIL BIT(18)
> #define VEC_CONFIG0_CHROMA_GAIN_MASK GENMASK(17, 16)
> #define VEC_CONFIG0_CHROMA_GAIN_UNITY (0 << 16)
> @@ -76,6 +77,27 @@
> #define VEC_SOFT_RESET 0x10c
> #define VEC_CLMP0_START 0x144
> #define VEC_CLMP0_END 0x148
> +
> +/*
> + * These set the color subcarrier frequency
> + * if VEC_CONFIG1_CUSTOM_FREQ is enabled.
> + *
> + * VEC_FREQ1_0 contains the most significant 16-bit half-word,
> + * VEC_FREQ3_2 contains the least significant 16-bit half-word.
> + * 0x80000000 seems to be equivalent to the pixel clock
> + * (which itself is the VEC clock divided by 8).
> + *
> + * Reference values (with the default pixel clock of 13.5 MHz):
> + *
> + * NTSC (3579545.[45] Hz) - 0x21F07C1F
> + * PAL (4433618.75 Hz) - 0x2A098ACB
> + * PAL-M (3575611.[888111] Hz) - 0x21E6EFE3
> + * PAL-N (3582056.25 Hz) - 0x21F69446
> + *
> + * NOTE: For SECAM, it is used as the Dr center frequency,
> + * regardless of whether VEC_CONFIG1_CUSTOM_FREQ is enabled or not;
> + * that is specified as 4406250 Hz, which corresponds to 0x29C71C72.
> + */
> #define VEC_FREQ3_2 0x180
> #define VEC_FREQ1_0 0x184
>
> @@ -118,6 +140,14 @@
>
> #define VEC_INTERRUPT_CONTROL 0x190
> #define VEC_INTERRUPT_STATUS 0x194
> +
> +/*
> + * Db center frequency for SECAM; the clock for this is the same as for
> + * VEC_FREQ3_2/VEC_FREQ1_0, which is used for Dr center frequency.
> + *
> + * This is specified as 4250000 Hz, which corresponds to 0x284BDA13.
> + * That is also the default value, so no need to set it explicitly.
> + */
> #define VEC_FCW_SECAM_B 0x198
> #define VEC_SECAM_GAIN_VAL 0x19c
>
> @@ -197,10 +227,15 @@ enum vc4_vec_tv_mode_id {
> VC4_VEC_TV_MODE_NTSC_J,
> VC4_VEC_TV_MODE_PAL,
> VC4_VEC_TV_MODE_PAL_M,
> + VC4_VEC_TV_MODE_NTSC_443,
> + VC4_VEC_TV_MODE_PAL_60,
> + VC4_VEC_TV_MODE_PAL_N,
> + VC4_VEC_TV_MODE_SECAM,
> };
>
> struct vc4_vec_tv_mode {
> unsigned int mode;
> + u16 expected_htotal;
> u32 config0;
> u32 config1;
> u32 custom_freq;
> @@ -236,35 +271,68 @@ static const struct debugfs_reg32 vec_regs[] = {
> static const struct vc4_vec_tv_mode vc4_vec_tv_modes[] = {
> {
> .mode = DRM_MODE_TV_MODE_NTSC,
> + .expected_htotal = 858,
> .config0 = VEC_CONFIG0_NTSC_STD | VEC_CONFIG0_PDEN,
> .config1 = VEC_CONFIG1_C_CVBS_CVBS,
> },
> + {
> + .mode = DRM_MODE_TV_MODE_NTSC_443,
> + .expected_htotal = 858,
> + .config0 = VEC_CONFIG0_NTSC_STD,
> + .config1 = VEC_CONFIG1_C_CVBS_CVBS | VEC_CONFIG1_CUSTOM_FREQ,
> + .custom_freq = 0x2a098acb,
> + },
> {
> .mode = DRM_MODE_TV_MODE_NTSC_J,
> + .expected_htotal = 858,
> .config0 = VEC_CONFIG0_NTSC_STD,
> .config1 = VEC_CONFIG1_C_CVBS_CVBS,
> },
> {
> .mode = DRM_MODE_TV_MODE_PAL,
> + .expected_htotal = 864,
> .config0 = VEC_CONFIG0_PAL_BDGHI_STD,
> .config1 = VEC_CONFIG1_C_CVBS_CVBS,
> },
> + {
> + /* PAL-60 */
> + .mode = DRM_MODE_TV_MODE_PAL,
> + .expected_htotal = 858,
> + .config0 = VEC_CONFIG0_PAL_M_STD,
> + .config1 = VEC_CONFIG1_C_CVBS_CVBS | VEC_CONFIG1_CUSTOM_FREQ,
> + .custom_freq = 0x2a098acb,
> + },
> {
> .mode = DRM_MODE_TV_MODE_PAL_M,
> + .expected_htotal = 858,
> .config0 = VEC_CONFIG0_PAL_M_STD,
> .config1 = VEC_CONFIG1_C_CVBS_CVBS,
> },
> + {
> + .mode = DRM_MODE_TV_MODE_PAL_N,
> + .expected_htotal = 864,
> + .config0 = VEC_CONFIG0_PAL_N_STD,
> + .config1 = VEC_CONFIG1_C_CVBS_CVBS,
> + },
> + {
> + .mode = DRM_MODE_TV_MODE_SECAM,
> + .expected_htotal = 864,
> + .config0 = VEC_CONFIG0_SECAM_STD,
> + .config1 = VEC_CONFIG1_C_CVBS_CVBS,
> + .custom_freq = 0x29c71c72,
> + },
> };
>
> static inline const struct vc4_vec_tv_mode *
> -vc4_vec_tv_mode_lookup(unsigned int mode)
> +vc4_vec_tv_mode_lookup(unsigned int mode, u16 htotal)
> {
> unsigned int i;
>
> for (i = 0; i < ARRAY_SIZE(vc4_vec_tv_modes); i++) {
> const struct vc4_vec_tv_mode *tv_mode = &vc4_vec_tv_modes[i];
>
> - if (tv_mode->mode == mode)
> + if (tv_mode->mode == mode &&
> + tv_mode->expected_htotal == htotal)
> return tv_mode;
> }
>
> @@ -273,9 +341,13 @@ vc4_vec_tv_mode_lookup(unsigned int mode)
>
> static const struct drm_prop_enum_list legacy_tv_mode_names[] = {
> { VC4_VEC_TV_MODE_NTSC, "NTSC", },
> + { VC4_VEC_TV_MODE_NTSC_443, "NTSC-443", },
> { VC4_VEC_TV_MODE_NTSC_J, "NTSC-J", },
> { VC4_VEC_TV_MODE_PAL, "PAL", },
> + { VC4_VEC_TV_MODE_PAL_60, "PAL-60", },
> { VC4_VEC_TV_MODE_PAL_M, "PAL-M", },
> + { VC4_VEC_TV_MODE_PAL_N, "PAL-N", },
> + { VC4_VEC_TV_MODE_SECAM, "SECAM", },
> };
>
> static enum drm_connector_status
> @@ -306,11 +378,16 @@ vc4_vec_connector_set_property(struct drm_connector *connector,
> state->tv.mode = DRM_MODE_TV_MODE_NTSC;
> break;
>
> + case VC4_VEC_TV_MODE_NTSC_443:
> + state->tv.mode = DRM_MODE_TV_MODE_NTSC_443;
> + break;
> +
> case VC4_VEC_TV_MODE_NTSC_J:
> state->tv.mode = DRM_MODE_TV_MODE_NTSC_J;
> break;
>
> case VC4_VEC_TV_MODE_PAL:
> + case VC4_VEC_TV_MODE_PAL_60:
> state->tv.mode = DRM_MODE_TV_MODE_PAL;
> break;
>
> @@ -318,6 +395,14 @@ vc4_vec_connector_set_property(struct drm_connector *connector,
> state->tv.mode = DRM_MODE_TV_MODE_PAL_M;
> break;
>
> + case VC4_VEC_TV_MODE_PAL_N:
> + state->tv.mode = DRM_MODE_TV_MODE_PAL_N;
> + break;
> +
> + case VC4_VEC_TV_MODE_SECAM:
> + state->tv.mode = DRM_MODE_TV_MODE_SECAM;
> + break;
> +
> default:
> return -EINVAL;
> }
> @@ -341,6 +426,10 @@ vc4_vec_connector_get_property(struct drm_connector *connector,
> *val = VC4_VEC_TV_MODE_NTSC;
> break;
>
> + case DRM_MODE_TV_MODE_NTSC_443:
> + *val = VC4_VEC_TV_MODE_NTSC_443;
> + break;
> +
> case DRM_MODE_TV_MODE_NTSC_J:
> *val = VC4_VEC_TV_MODE_NTSC_J;
> break;
> @@ -353,6 +442,14 @@ vc4_vec_connector_get_property(struct drm_connector *connector,
> *val = VC4_VEC_TV_MODE_PAL_M;
> break;
>
> + case DRM_MODE_TV_MODE_PAL_N:
> + *val = VC4_VEC_TV_MODE_PAL_N;
> + break;
> +
> + case DRM_MODE_TV_MODE_SECAM:
> + *val = VC4_VEC_TV_MODE_SECAM;
> + break;
> +
> default:
> return -EINVAL;
> }
> @@ -448,13 +545,16 @@ static void vc4_vec_encoder_enable(struct drm_encoder *encoder,
> struct drm_connector *connector = &vec->connector;
> struct drm_connector_state *conn_state =
> drm_atomic_get_new_connector_state(state, connector);
> + struct drm_display_mode *adjusted_mode =
> + &encoder->crtc->state->adjusted_mode;
> const struct vc4_vec_tv_mode *tv_mode;
> int idx, ret;
>
> if (!drm_dev_enter(drm, &idx))
> return;
>
> - tv_mode = vc4_vec_tv_mode_lookup(conn_state->tv.mode);
> + tv_mode = vc4_vec_tv_mode_lookup(conn_state->tv.mode,
> + adjusted_mode->htotal);
> if (!tv_mode)
> goto err_dev_exit;
>
> @@ -648,9 +748,12 @@ static int vc4_vec_bind(struct device *dev, struct device *master, void *data)
>
> ret = drm_mode_create_tv_properties(drm,
> BIT(DRM_MODE_TV_MODE_NTSC) |
> + BIT(DRM_MODE_TV_MODE_NTSC_443) |
> BIT(DRM_MODE_TV_MODE_NTSC_J) |
> BIT(DRM_MODE_TV_MODE_PAL) |
> - BIT(DRM_MODE_TV_MODE_PAL_M));
> + BIT(DRM_MODE_TV_MODE_PAL_M) |
> + BIT(DRM_MODE_TV_MODE_PAL_N) |
> + BIT(DRM_MODE_TV_MODE_SECAM));
> if (ret)
> return ret;
>
>