Re: [PATCH 4/4] drm/panel/ili9341: Support DPI panels

[Sam Ravnborg <sam@ravnborg.org>]

Hi Noralf.

On Thu, Aug 01, 2019 at 03:52:49PM +0200, Noralf Trønnes wrote:
> Add support for panels that use the DPI interface.
> ILI9341 has onboard RAM so the assumption made here is that all such
> panels support pixel upload over DBI.
> 
> The presence/absense of the Device Tree 'port' node decides which
> interface is used for pixel transfer.
> 
> Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
> ---
>  drivers/gpu/drm/panel/panel-ilitek-ili9341.c | 56 ++++++++++++++++----
>  1 file changed, 45 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panel/panel-ilitek-ili9341.c b/drivers/gpu/drm/panel/panel-ilitek-ili9341.c
> index f6082fa2a389..7cbfd739c7fd 100644
> --- a/drivers/gpu/drm/panel/panel-ilitek-ili9341.c
> +++ b/drivers/gpu/drm/panel/panel-ilitek-ili9341.c
> @@ -11,6 +11,7 @@
>  #include <linux/gpio/consumer.h>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
> +#include <linux/of_graph.h>
>  #include <linux/pm.h>
>  #include <linux/property.h>
>  #include <linux/regulator/consumer.h>
> @@ -53,11 +54,13 @@
>  struct ili9341_config {
>  	const struct drm_panel_funcs *funcs;
>  	const struct drm_display_mode *mode;
> +	bool no_dpi;
>  };
>  
>  struct ili9341 {
>  	struct mipi_dbi_dev dbidev; /* This must be the first entry */
>  	struct drm_panel panel;
> +	bool use_dpi;
>  	struct regulator *regulator;
>  	struct backlight_device *backlight;
>  	const struct ili9341_config *conf;
> @@ -174,6 +177,7 @@ static const struct drm_display_mode yx240qv29_mode = {
>  static const struct ili9341_config yx240qv29_data = {
>  	.funcs = &yx240qv29_funcs,
>  	.mode = &yx240qv29_mode,
> +	.no_dpi = true,
>  };
>  
>  static int mi0283qt_prepare(struct drm_panel *panel)
> @@ -291,6 +295,7 @@ static const struct drm_display_mode mi0283qt_mode = {
>  static const struct ili9341_config mi0283qt_data = {
>  	.funcs = &mi0283qt_drm_funcs,
>  	.mode = &mi0283qt_mode,
> +	.no_dpi = true,
>  };
>  
>  /* Legacy, DRM driver name is ABI */
> @@ -303,6 +308,7 @@ static int ili9341_probe(struct spi_device *spi)
>  	const struct spi_device_id *spi_id;
>  	struct device *dev = &spi->dev;
>  	struct drm_driver *driver;
> +	struct device_node *port;
>  	struct mipi_dbi *dbi;
>  	struct gpio_desc *dc;
>  	struct ili9341 *ili;
> @@ -357,21 +363,44 @@ static int ili9341_probe(struct spi_device *spi)
>  	ili->panel.dev = dev;
>  	ili->panel.funcs = ili->conf->funcs;
>  
> -	if (ili->conf == &mi0283qt_data)
> -		driver = &mi0283qt_drm_driver;
> -	else
> -		driver = &ili9341_drm_driver;
>  
> -	return drm_mipi_dbi_panel_register(&ili->panel, &ili->dbidev, driver,
> -					   ili->conf->mode, rotation);
> +	port = of_get_child_by_name(dev->of_node, "port");
> +	if (port) {
> +		of_node_put(port);
> +		ili->use_dpi = true;
> +	}
> +
> +	if (ili->conf->no_dpi)
> +		ili->use_dpi = false;
> +
> +	if (ili->use_dpi) {
> +		ret = drm_panel_add(&ili->panel);
> +	} else {
> +		if (ili->conf == &mi0283qt_data)
> +			driver = &mi0283qt_drm_driver;
> +		else
> +			driver = &ili9341_drm_driver;
> +
> +		ret = drm_mipi_dbi_panel_register(&ili->panel, &ili->dbidev, driver,
> +						  ili->conf->mode, rotation);
> +	}
> +
> +	return ret;
>  }
>  
>  static int ili9341_remove(struct spi_device *spi)
>  {
>  	struct ili9341 *ili = spi_get_drvdata(spi);
>  
> -	drm_dev_unplug(&ili->dbidev.drm);
> -	drm_atomic_helper_shutdown(&ili->dbidev.drm);
> +	if (ili->use_dpi) {
> +		drm_panel_remove(&ili->panel);
> +		drm_panel_disable(&ili->panel);
> +		drm_panel_unprepare(&ili->panel);
> +		kfree(ili);
At first I thought - order is wrong.
But drm_panel_remove() prevents display drivers from using the driver.
And this will not invalidate the other calls.
Maybe add a short comment?

	Sam


> +	} else {
> +		drm_dev_unplug(&ili->dbidev.drm);
> +		drm_atomic_helper_shutdown(&ili->dbidev.drm);
> +	}
>  
>  	return 0;
>  }
> @@ -380,21 +409,26 @@ static void ili9341_shutdown(struct spi_device *spi)
>  {
>  	struct ili9341 *ili = spi_get_drvdata(spi);
>  
> -	drm_atomic_helper_shutdown(&ili->dbidev.drm);
> +	if (!ili->use_dpi)
> +		drm_atomic_helper_shutdown(&ili->dbidev.drm);
>  }
>  
>  static int __maybe_unused ili9341_pm_suspend(struct device *dev)
>  {
>  	struct ili9341 *ili = dev_get_drvdata(dev);
>  
> -	return drm_mode_config_helper_suspend(&ili->dbidev.drm);
> +	if (!ili->use_dpi)
> +		return drm_mode_config_helper_suspend(&ili->dbidev.drm);
> +
> +	return 0;
>  }
>  
>  static int __maybe_unused ili9341_pm_resume(struct device *dev)
>  {
>  	struct ili9341 *ili = dev_get_drvdata(dev);
>  
> -	drm_mode_config_helper_resume(&ili->dbidev.drm);
> +	if (!ili->use_dpi)
> +		drm_mode_config_helper_resume(&ili->dbidev.drm);
>  
>  	return 0;
>  }
> -- 
> 2.20.1
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