Re: [PATCH v3 4/5] drm/panel: st7701: Add support for SPI for configuration

[Neil Armstrong]

On 06/07/2024 12:23, Hironori KIKUCHI wrote:
> The ST7701 supports not only MIPI DSI, but also SPI as an interface
> for configuration. To support a panel connected via SPI with an RGB
> parallel interface, add support for SPI using MIPI DBI helpers.
>
> Signed-off-by: Hironori KIKUCHI <kikuchan98@xxxxxxxxx>
> ---
>   drivers/gpu/drm/panel/Kconfig                 |   3 +-
>   drivers/gpu/drm/panel/panel-sitronix-st7701.c | 123 +++++++++++++++---
>   2 files changed, 110 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
> index 2ae0eb0638f..3dd52869520 100644
> --- a/drivers/gpu/drm/panel/Kconfig
> +++ b/drivers/gpu/drm/panel/Kconfig
> @@ -755,7 +755,8 @@ config DRM_PANEL_SHARP_LS060T1SX01
>   config DRM_PANEL_SITRONIX_ST7701
>   	tristate "Sitronix ST7701 panel driver"
>   	depends on OF
> -	depends on DRM_MIPI_DSI
> +	depends on SPI || DRM_MIPI_DSI
> +	select DRM_MIPI_DBI if SPI
>   	depends on BACKLIGHT_CLASS_DEVICE
>   	help
>   	  Say Y here if you want to enable support for the Sitronix
> diff --git a/drivers/gpu/drm/panel/panel-sitronix-st7701.c b/drivers/gpu/drm/panel/panel-sitronix-st7701.c
> index a0644f7a4c8..9e83a760a8a 100644
> --- a/drivers/gpu/drm/panel/panel-sitronix-st7701.c
> +++ b/drivers/gpu/drm/panel/panel-sitronix-st7701.c
> @@ -4,6 +4,7 @@
>    * Author: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
>    */
>   
> +#include <drm/drm_mipi_dbi.h>
>   #include <drm/drm_mipi_dsi.h>
>   #include <drm/drm_modes.h>
>   #include <drm/drm_panel.h>
> @@ -14,6 +15,7 @@
>   #include <linux/module.h>
>   #include <linux/of.h>
>   #include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.h>
>   
>   #include <video/mipi_display.h>
>   
> @@ -130,12 +132,16 @@ struct st7701_panel_desc {
>   struct st7701 {
>   	struct drm_panel panel;
>   	struct mipi_dsi_device *dsi;
> +	struct mipi_dbi dbi;
>   	const struct st7701_panel_desc *desc;
>   
>   	struct regulator_bulk_data supplies[2];
>   	struct gpio_desc *reset;
>   	unsigned int sleep_delay;
>   	enum drm_panel_orientation orientation;
> +
> +	int (*write_command)(struct st7701 *st7701, u8 cmd, const u8 *seq,
> +			     size_t len);
>   };
>   
>   static inline struct st7701 *panel_to_st7701(struct drm_panel *panel)
> @@ -143,16 +149,22 @@ static inline struct st7701 *panel_to_st7701(struct drm_panel *panel)
>   	return container_of(panel, struct st7701, panel);
>   }
>   
> -static inline int st7701_dsi_write(struct st7701 *st7701, const void *seq,
> -				   size_t len)
> +static int st7701_dsi_write(struct st7701 *st7701, u8 cmd, const u8 *seq,
> +			    size_t len)
>   {
> -	return mipi_dsi_dcs_write_buffer(st7701->dsi, seq, len);
> +	return mipi_dsi_dcs_write(st7701->dsi, cmd, seq, len);
>   }
>   
> -#define ST7701_WRITE(st7701, seq...)				\
> -	{							\
> -		const u8 d[] = { seq };				\
> -		st7701_dsi_write(st7701, d, ARRAY_SIZE(d));	\
> +static int st7701_dbi_write(struct st7701 *st7701, u8 cmd, const u8 *seq,
> +			    size_t len)
> +{
> +	return mipi_dbi_command_stackbuf(&st7701->dbi, cmd, seq, len);
> +}
> +
> +#define ST7701_WRITE(st7701, cmd, seq...)				\
> +	{								\
> +		const u8 d[] = { seq };					\
> +		st7701->write_command(st7701, cmd, d, ARRAY_SIZE(d));	\
>   	}
>   
>   static u8 st7701_vgls_map(struct st7701 *st7701)
> @@ -211,10 +223,10 @@ static void st7701_init_sequence(struct st7701 *st7701)
>   	/* Command2, BK0 */
>   	st7701_switch_cmd_bkx(st7701, true, 0);
>   
> -	mipi_dsi_dcs_write(st7701->dsi, ST7701_CMD2_BK0_PVGAMCTRL,
> -			   desc->pv_gamma, ARRAY_SIZE(desc->pv_gamma));
> -	mipi_dsi_dcs_write(st7701->dsi, ST7701_CMD2_BK0_NVGAMCTRL,
> -			   desc->nv_gamma, ARRAY_SIZE(desc->nv_gamma));
> +	st7701->write_command(st7701, ST7701_CMD2_BK0_PVGAMCTRL, desc->pv_gamma,
> +			      ARRAY_SIZE(desc->pv_gamma));
> +	st7701->write_command(st7701, ST7701_CMD2_BK0_NVGAMCTRL, desc->nv_gamma,
> +			      ARRAY_SIZE(desc->nv_gamma));
>   	/*
>   	 * Vertical line count configuration:
>   	 * Line[6:0]: select number of vertical lines of the TFT matrix in
> @@ -1051,6 +1063,10 @@ static int st7701_dsi_probe(struct mipi_dsi_device *dsi)
>   
>   	st7701 = dev_get_drvdata(&dsi->dev);
>   	st7701->dsi = dsi;
> +	st7701->write_command = st7701_dsi_write;
> +
> +	if (!st7701->desc->lanes)
> +		return dev_err_probe(&dsi->dev, -EINVAL, "This panel is not for MIPI DSI\n");
>   
>   	dsi->mode_flags = MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST |
>   			  MIPI_DSI_MODE_LPM | MIPI_DSI_CLOCK_NON_CONTINUOUS;
> @@ -1064,30 +1080,107 @@ static int st7701_dsi_probe(struct mipi_dsi_device *dsi)
>   	return 0;
>   }
>   
> +static int st7701_spi_probe(struct spi_device *spi)
> +{
> +	struct st7701 *st7701;
> +	struct gpio_desc *dc;
> +	int err;
> +
> +	err = st7701_probe(&spi->dev, DRM_MODE_CONNECTOR_DPI);
> +	if (err)
> +		return err;
> +
> +	st7701 = dev_get_drvdata(&spi->dev);
> +	st7701->write_command = st7701_dbi_write;
> +
> +	dc = devm_gpiod_get_optional(&spi->dev, "dc", GPIOD_OUT_LOW);
> +	if (IS_ERR(dc))
> +		return dev_err_probe(&spi->dev, PTR_ERR(dc), "Failed to get GPIO for D/CX\n");
> +
> +	err = mipi_dbi_spi_init(spi, &st7701->dbi, dc);
> +	if (err)
> +		return dev_err_probe(&spi->dev, err, "Failed to init MIPI DBI\n");
> +	st7701->dbi.read_commands = NULL;
> +
> +	return 0;
> +}
> +
>   static void st7701_dsi_remove(struct mipi_dsi_device *dsi)
>   {
>   	mipi_dsi_detach(dsi);
>   }
>   
> -static const struct of_device_id st7701_of_match[] = {
> +static const struct of_device_id st7701_dsi_of_match[] = {
>   	{ .compatible = "anbernic,rg-arc-panel", .data = &rg_arc_desc },
>   	{ .compatible = "densitron,dmt028vghmcmi-1a", .data = &dmt028vghmcmi_1a_desc },
>   	{ .compatible = "elida,kd50t048a", .data = &kd50t048a_desc },
>   	{ .compatible = "techstar,ts8550b", .data = &ts8550b_desc },
>   	{ }
>   };
> -MODULE_DEVICE_TABLE(of, st7701_of_match);
> +MODULE_DEVICE_TABLE(of, st7701_dsi_of_match);
> +
> +static const struct of_device_id st7701_spi_of_match[] = {
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, st7701_spi_of_match);
> +
> +static const struct spi_device_id st7701_spi_ids[] = {
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(spi, st7701_spi_ids);
>   
>   static struct mipi_dsi_driver st7701_dsi_driver = {
>   	.probe		= st7701_dsi_probe,
>   	.remove		= st7701_dsi_remove,
>   	.driver = {
>   		.name		= "st7701",
> -		.of_match_table	= st7701_of_match,
> +		.of_match_table	= st7701_dsi_of_match,
>   	},
>   };
> -module_mipi_dsi_driver(st7701_dsi_driver);
> +
> +static struct spi_driver st7701_spi_driver = {
> +	.probe		= st7701_spi_probe,
> +	.id_table	= st7701_spi_ids,
> +	.driver = {
> +		.name		= "st7701",
> +		.of_match_table	= st7701_spi_of_match,
> +	},
> +};
> +
> +static int __init st7701_driver_init(void)
> +{
> +	int err;
> +
> +	if (IS_ENABLED(CONFIG_SPI)) {
> +		err = spi_register_driver(&st7701_spi_driver);
> +		if (err)
> +			return err;
> +	}
> +
> +	if (IS_ENABLED(CONFIG_DRM_MIPI_DSI)) {
> +		err = mipi_dsi_driver_register(&st7701_dsi_driver);
> +		if (err) {
> +			if (IS_ENABLED(CONFIG_SPI))
> +				spi_unregister_driver(&st7701_spi_driver);
> +			return err;
> +		}
> +	}
> +
> +	return 0;
> +}
> +module_init(st7701_driver_init);
> +
> +static void __exit st7701_driver_exit(void)
> +{
> +	if (IS_ENABLED(CONFIG_DRM_MIPI_DSI))
> +		mipi_dsi_driver_unregister(&st7701_dsi_driver);
> +
> +	if (IS_ENABLED(CONFIG_SPI))
> +		spi_unregister_driver(&st7701_spi_driver);
> +}
> +module_exit(st7701_driver_exit);
>   
>   MODULE_AUTHOR("Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>");
> +MODULE_AUTHOR("Hironori KIKUCHI <kikuchan98@xxxxxxxxx>");
>   MODULE_DESCRIPTION("Sitronix ST7701 LCD Panel Driver");
>   MODULE_LICENSE("GPL");

Reviewed-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>