[RFC,v4,0/7] Add FS035VG158 panel

Hello there,

This RFC introduces support for the FS035VG158 LCD panel, cleaning up
the nv3052c driver on the way and documentating existing panel code.

This patch series is at a bit of a standstill: I have gotten feedback
that it should instead use the Leadtek LTK035C5444T panel init sequence
instead of Fascontek's provided sequence which is almost identical.

I don't feel comfortable providing a patch that does this unless someone
can explain why the changes Fascontek have made aren't critical.

I would like feedback to know if this is a blocker for this patch set,
or otherwise what needs to be done to get it merged.

John.

v3 -> v4:
- Mark panel_regs_len as unsigned

v2 -> v3:
- Dropped patches that add extra sleep time

v1 -> v2:
- Fixed a variable declaration style error
- Cleaned up device tree yaml

John Watts (7):
  drm/panel: nv3052c: Document known register names
  drm/panel: nv3052c: Add SPI device IDs
  drm/panel: nv3052c: Allow specifying registers per panel
  drm/panel: nv3052c: Add Fascontek FS035VG158 LCD display
  dt-bindings: display: panel: Clean up leadtek,ltk035c5444t properties
  dt-bindings: vendor-prefixes: Add fascontek
  dt-bindings: display: panel: add Fascontek FS035VG158 panel

 .../display/panel/fascontek,fs035vg158.yaml   |  56 ++
 .../display/panel/leadtek,ltk035c5444t.yaml   |   8 +-
 .../devicetree/bindings/vendor-prefixes.yaml  |   2 +
 .../gpu/drm/panel/panel-newvision-nv3052c.c   | 515 +++++++++++++-----
 4 files changed, 437 insertions(+), 144 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/display/panel/fascontek,fs035vg158.yaml

On 10/30/2023 12:23 AM, John Watts wrote:
> Panel initialization registers are per-display and not tied to the
> controller itself. Different panels will specify their own registers.
> Attach the sequences to the panel info struct so future panels
> can specify their own sequences.

Hi John,

Reviewed-by: Jessica Zhang <quic_jesszhan@quicinc.com>

Thanks,

Jessica Zhang

> 
> Signed-off-by: John Watts <contact@jookia.org>
> ---
>   .../gpu/drm/panel/panel-newvision-nv3052c.c   | 24 ++++++++++++-------
>   1 file changed, 15 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panel/panel-newvision-nv3052c.c b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> index 90dea21f9856..b0114b5e8554 100644
> --- a/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> +++ b/drivers/gpu/drm/panel/panel-newvision-nv3052c.c
> @@ -20,11 +20,18 @@
>   #include <drm/drm_modes.h>
>   #include <drm/drm_panel.h>
>   
> +struct nv3052c_reg {
> +	u8 cmd;
> +	u8 val;
> +};
> +
>   struct nv3052c_panel_info {
>   	const struct drm_display_mode *display_modes;
>   	unsigned int num_modes;
>   	u16 width_mm, height_mm;
>   	u32 bus_format, bus_flags;
> +	const struct nv3052c_reg *panel_regs;
> +	unsigned int panel_regs_len;
>   };
>   
>   struct nv3052c {
> @@ -36,12 +43,7 @@ struct nv3052c {
>   	struct gpio_desc *reset_gpio;
>   };
>   
> -struct nv3052c_reg {
> -	u8 cmd;
> -	u8 val;
> -};
> -
> -static const struct nv3052c_reg nv3052c_panel_regs[] = {
> +static const struct nv3052c_reg ltk035c5444t_panel_regs[] = {
>   	// EXTC Command set enable, select page 1
>   	{ 0xff, 0x30 }, { 0xff, 0x52 }, { 0xff, 0x01 },
>   	// Mostly unknown registers
> @@ -244,6 +246,8 @@ static inline struct nv3052c *to_nv3052c(struct drm_panel *panel)
>   static int nv3052c_prepare(struct drm_panel *panel)
>   {
>   	struct nv3052c *priv = to_nv3052c(panel);
> +	const struct nv3052c_reg *panel_regs = priv->panel_info->panel_regs;
> +	unsigned int panel_regs_len = priv->panel_info->panel_regs_len;
>   	struct mipi_dbi *dbi = &priv->dbi;
>   	unsigned int i;
>   	int err;
> @@ -260,9 +264,9 @@ static int nv3052c_prepare(struct drm_panel *panel)
>   	gpiod_set_value_cansleep(priv->reset_gpio, 0);
>   	usleep_range(5000, 20000);
>   
> -	for (i = 0; i < ARRAY_SIZE(nv3052c_panel_regs); i++) {
> -		err = mipi_dbi_command(dbi, nv3052c_panel_regs[i].cmd,
> -				       nv3052c_panel_regs[i].val);
> +	for (i = 0; i < panel_regs_len; i++) {
> +		err = mipi_dbi_command(dbi, panel_regs[i].cmd,
> +				       panel_regs[i].val);
>   
>   		if (err) {
>   			dev_err(priv->dev, "Unable to set register: %d\n", err);
> @@ -463,6 +467,8 @@ static const struct nv3052c_panel_info ltk035c5444t_panel_info = {
>   	.height_mm = 64,
>   	.bus_format = MEDIA_BUS_FMT_RGB888_1X24,
>   	.bus_flags = DRM_BUS_FLAG_DE_HIGH | DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE,
> +	.panel_regs = ltk035c5444t_panel_regs,
> +	.panel_regs_len = ARRAY_SIZE(ltk035c5444t_panel_regs),
>   };
>   
>   static const struct spi_device_id nv3052c_ids[] = {
> -- 
> 2.42.0
>