Re: [RFC PATCH 3/4] gpu/drm: Add TinyDRM for DSI/DBI panels

[Paul Cercueil <paul@crapouillou.net>]

Hi Sandy,

Le mer. 8 juil. 2020 à 10:26, Sandy Huang <sandy.huang01@yahoo.com> a 
écrit :
> Hi paul,
> 
>     After add this driver, the followinig usage scenarios can be 
> supported?
> 
>     panel 1. crtc->encoder->connector[edp/hdmi/mipi dsi] -> panel
> 
>     panel 2. Panel setup/control and framebuffer upload over SPI
> 
>     the two panel maybe display same/different conctent at same time.

Yes, should be totally possible.

Cheers,
-Paul

> 
> 在 2020/6/7 21:38, Paul Cercueil 写道:
>> The new API function mipi_dsi_maybe_register_tiny_driver() is 
>> supposed
>> to be called by DSI/DBI panel drivers at the end of their probe.
>> 
>> If it is detected that the panel is not connected to any controller,
>> because it has no port #0 node in Device Tree that points back to it,
>> then a TinyDRM driver is registered with it.
>> 
>> This TinyDRM driver expects that a DCS-compliant protocol is used by 
>> the
>> DSI/DBI panel and can only be used with these.
>> 
>> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>> ---
>>   drivers/gpu/drm/tiny/Kconfig    |   8 +
>>   drivers/gpu/drm/tiny/Makefile   |   1 +
>>   drivers/gpu/drm/tiny/tiny-dsi.c | 262 
>> ++++++++++++++++++++++++++++++++
>>   include/drm/drm_mipi_dsi.h      |  19 +++
>>   4 files changed, 290 insertions(+)
>>   create mode 100644 drivers/gpu/drm/tiny/tiny-dsi.c
>> 
>> diff --git a/drivers/gpu/drm/tiny/Kconfig 
>> b/drivers/gpu/drm/tiny/Kconfig
>> index 4160e74e4751..54ee58aecf66 100644
>> --- a/drivers/gpu/drm/tiny/Kconfig
>> +++ b/drivers/gpu/drm/tiny/Kconfig
>> @@ -9,6 +9,14 @@ config DRM_GM12U320
>>   	 This is a KMS driver for projectors which use the GM12U320 
>> chipset
>>   	 for video transfer over USB2/3, such as the Acer C120 mini 
>> projector.
>>   \x7f+config TINYDRM_DSI
>> +	tristate "DRM support for generic DBI/DSI display panels"
>> +	depends on DRM && DRM_MIPI_DSI
>> +	select DRM_MIPI_DBI
>> +	select DRM_KMS_CMA_HELPER
>> +	help
>> +	  DRM driver for generic DBI/DSI display panels
>> +
>>   config TINYDRM_HX8357D
>>   	tristate "DRM support for HX8357D display panels"
>>   	depends on DRM && SPI
>> diff --git a/drivers/gpu/drm/tiny/Makefile 
>> b/drivers/gpu/drm/tiny/Makefile
>> index c96ceee71453..49513db9a307 100644
>> --- a/drivers/gpu/drm/tiny/Makefile
>> +++ b/drivers/gpu/drm/tiny/Makefile
>> @@ -1,6 +1,7 @@
>>   # SPDX-License-Identifier: GPL-2.0-only
>>   \x7f  obj-$(CONFIG_DRM_GM12U320)		+= gm12u320.o
>> +obj-$(CONFIG_TINYDRM_DSI)		+= tiny-dsi.o
>>   obj-$(CONFIG_TINYDRM_HX8357D)		+= hx8357d.o
>>   obj-$(CONFIG_TINYDRM_ILI9225)		+= ili9225.o
>>   obj-$(CONFIG_TINYDRM_ILI9341)		+= ili9341.o
>> diff --git a/drivers/gpu/drm/tiny/tiny-dsi.c 
>> b/drivers/gpu/drm/tiny/tiny-dsi.c
>> new file mode 100644
>> index 000000000000..915e598844bd
>> --- /dev/null
>> +++ b/drivers/gpu/drm/tiny/tiny-dsi.c
>> @@ -0,0 +1,262 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * TinyDRM driver for standard DSI/DBI panels
>> + *
>> + * Copyright 2020 Paul Cercueil <paul@crapouillou.net>
>> + */
>> +
>> +#include <linux/module.h>
>> +
>> +#include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_damage_helper.h>
>> +#include <drm/drm_drv.h>
>> +#include <drm/drm_fb_helper.h>
>> +#include <drm/drm_fourcc.h>
>> +#include <drm/drm_gem_cma_helper.h>
>> +#include <drm/drm_gem_framebuffer_helper.h>
>> +#include <drm/drm_mipi_dbi.h>
>> +#include <drm/drm_mipi_dsi.h>
>> +#include <drm/drm_modeset_helper.h>
>> +#include <drm/drm_panel.h>
>> +#include <drm/drm_probe_helper.h>
>> +
>> +#include <video/mipi_display.h>
>> +
>> +struct tiny_dsi {
>> +	struct drm_device drm;
>> +	struct drm_connector connector;
>> +	struct drm_simple_display_pipe pipe;
>> +
>> +	struct mipi_dsi_device *dsi;
>> +	struct drm_panel *panel;
>> +};
>> +
>> +#define mipi_dcs_command(dsi, cmd, seq...) \
>> +({ \
>> +	u8 d[] = { seq }; \
>> +	mipi_dsi_dcs_write(dsi, cmd, d, ARRAY_SIZE(d)); \
>> +})
>> +
>> +static inline struct tiny_dsi *drm_to_tiny_dsi(struct drm_device 
>> *drm)
>> +{
>> +	return container_of(drm, struct tiny_dsi, drm);
>> +}
>> +
>> +static void tiny_dsi_fb_dirty(struct drm_framebuffer *fb, struct 
>> drm_rect *rect)
>> +{
>> +	struct drm_gem_object *gem = drm_gem_fb_get_obj(fb, 0);
>> +	struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(gem);
>> +	struct tiny_dsi *priv = drm_to_tiny_dsi(fb->dev);
>> +	unsigned int height = rect->y2 - rect->y1;
>> +	unsigned int width = rect->x2 - rect->x1;
>> +	bool fb_convert;
>> +	int idx, ret;
>> +	void *tr;
>> +
>> +	if (!drm_dev_enter(fb->dev, &idx))
>> +		return;
>> +
>> +	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, 
>> DRM_RECT_ARG(rect));
>> +
>> +	fb_convert = width != fb->width || height != fb->height
>> +		|| fb->format->format == DRM_FORMAT_XRGB8888;
>> +	if (fb_convert) {
>> +		tr = kzalloc(width * height * 2, GFP_KERNEL);
>> +
>> +		/* TODO: swap pixels if needed */
>> +		ret = mipi_dbi_buf_copy(tr, fb, rect, false);
>> +		if (ret)
>> +			goto err_msg;
>> +	} else {
>> +		tr = cma_obj->vaddr;
>> +	}
>> +
>> +	mipi_dcs_command(priv->dsi, MIPI_DCS_SET_COLUMN_ADDRESS,
>> +			 (rect->x1 >> 8) & 0xff, rect->x1 & 0xff,
>> +			 (rect->x2 >> 8) & 0xff, rect->x2 & 0xff);
>> +	mipi_dcs_command(priv->dsi, MIPI_DCS_SET_PAGE_ADDRESS,
>> +			 (rect->y1 >> 8) & 0xff, rect->y1 & 0xff,
>> +			 (rect->y2 >> 8) & 0xff, rect->y2 & 0xff);
>> +
>> +	ret = mipi_dsi_dcs_write(priv->dsi, MIPI_DCS_WRITE_MEMORY_START,
>> +				 tr, width * height * 2);
>> +err_msg:
>> +	if (ret)
>> +		dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
>> +
>> +	if (fb_convert)
>> +		kfree(tr);
>> +	drm_dev_exit(idx);
>> +}
>> +
>> +static void tiny_dsi_enable(struct drm_simple_display_pipe *pipe,
>> +			    struct drm_crtc_state *crtc_state,
>> +			    struct drm_plane_state *plane_state)
>> +{
>> +	struct tiny_dsi *priv = drm_to_tiny_dsi(pipe->crtc.dev);
>> +
>> +	drm_panel_enable(priv->panel);
>> +}
>> +
>> +static void tiny_dsi_disable(struct drm_simple_display_pipe *pipe)
>> +{
>> +	struct tiny_dsi *priv = drm_to_tiny_dsi(pipe->crtc.dev);
>> +
>> +	drm_panel_disable(priv->panel);
>> +}
>> +
>> +static void tiny_dsi_update(struct drm_simple_display_pipe *pipe,
>> +			    struct drm_plane_state *old_state)
>> +{
>> +	struct drm_plane_state *state = pipe->plane.state;
>> +	struct drm_rect rect;
>> +
>> +	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
>> +		tiny_dsi_fb_dirty(state->fb, &rect);
>> +}
>> +
>> +static const struct drm_simple_display_pipe_funcs 
>> tiny_dsi_pipe_funcs = {
>> +	.enable = tiny_dsi_enable,
>> +	.disable = tiny_dsi_disable,
>> +	.update = tiny_dsi_update,
>> +	.prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
>> +};
>> +
>> +static int tiny_dsi_connector_get_modes(struct drm_connector 
>> *connector)
>> +{
>> +	struct tiny_dsi *priv = drm_to_tiny_dsi(connector->dev);
>> +
>> +	return drm_panel_get_modes(priv->panel, connector);
>> +}
>> +
>> +static const struct drm_connector_helper_funcs 
>> tiny_dsi_connector_hfuncs = {
>> +	.get_modes = tiny_dsi_connector_get_modes,
>> +};
>> +
>> +static const struct drm_connector_funcs tiny_dsi_connector_funcs = {
>> +	.reset = drm_atomic_helper_connector_reset,
>> +	.fill_modes = drm_helper_probe_single_connector_modes,
>> +	.destroy = drm_connector_cleanup,
>> +	.atomic_duplicate_state = 
>> drm_atomic_helper_connector_duplicate_state,
>> +	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
>> +};
>> +
>> +DEFINE_DRM_GEM_CMA_FOPS(tiny_dsi_fops);
>> +
>> +static const uint32_t tiny_dsi_formats[] = {
>> +	DRM_FORMAT_RGB565,
>> +	DRM_FORMAT_XRGB8888,
>> +};
>> +
>> +static const struct drm_mode_config_funcs 
>> tiny_dsi_mode_config_funcs = {
>> +	.fb_create = drm_gem_fb_create_with_dirty,
>> +	.atomic_check = drm_atomic_helper_check,
>> +	.atomic_commit = drm_atomic_helper_commit,
>> +};
>> +
>> +static void tiny_dsi_release(struct drm_device *drm)
>> +{
>> +	struct tiny_dsi *priv = drm_to_tiny_dsi(drm);
>> +
>> +	drm_mode_config_cleanup(drm);
>> +	drm_dev_fini(drm);
>> +	kfree(priv);
>> +}
>> +
>> +static struct drm_driver tiny_dsi_driver = {
>> +	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
>> +	.fops			= &tiny_dsi_fops,
>> +	.release		= tiny_dsi_release,
>> +	DRM_GEM_CMA_VMAP_DRIVER_OPS,
>> +	.name			= "tiny-dsi",
>> +	.desc			= "Tiny DSI",
>> +	.date			= "20200605",
>> +	.major			= 1,
>> +	.minor			= 0,
>> +};
>> +
>> +static void tiny_dsi_remove(void *drm)
>> +{
>> +	drm_dev_unplug(drm);
>> +	drm_atomic_helper_shutdown(drm);
>> +}
>> +
>> +int mipi_dsi_register_tiny_driver(struct mipi_dsi_device *dsi)
>> +{
>> +	struct device *dev = &dsi->dev;
>> +	struct drm_device *drm;
>> +	struct tiny_dsi *priv;
>> +	static const uint64_t modifiers[] = {
>> +		DRM_FORMAT_MOD_LINEAR,
>> +		DRM_FORMAT_MOD_INVALID
>> +	};
>> +	int ret;
>> +
>> +	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
>> +	if (!priv)
>> +		return -ENOMEM;
>> +
>> +	priv->dsi = dsi;
>> +	drm = &priv->drm;
>> +
>> +	ret = devm_drm_dev_init(dev, drm, &tiny_dsi_driver);
>> +	if (ret) {
>> +		kfree(priv);
>> +		return ret;
>> +	}
>> +
>> +	drm_mode_config_init(drm);
>> +
>> +	priv->panel = of_drm_find_panel(dev->of_node);
>> +	if (IS_ERR(priv->panel)) {
>> +		dev_err(dev, "Unable to find panel\n");
>> +		return PTR_ERR(priv->panel);
>> +	}
>> +
>> +	drm->mode_config.preferred_depth = 16;
>> +
>> +	drm->mode_config.funcs = &tiny_dsi_mode_config_funcs;
>> +	drm->mode_config.min_width = 0;
>> +	drm->mode_config.min_height = 0;
>> +	drm->mode_config.max_width = 4096;
>> +	drm->mode_config.max_height = 4096;
>> +
>> +	drm_connector_helper_add(&priv->connector, 
>> &tiny_dsi_connector_hfuncs);
>> +	ret = drm_connector_init(drm, &priv->connector, 
>> &tiny_dsi_connector_funcs,
>> +				 DRM_MODE_CONNECTOR_DSI);
>> +	if (ret) {
>> +		dev_err(dev, "Unable to init connector\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = drm_simple_display_pipe_init(drm, &priv->pipe, 
>> &tiny_dsi_pipe_funcs,
>> +					   tiny_dsi_formats, ARRAY_SIZE(tiny_dsi_formats),
>> +					   modifiers, &priv->connector);
>> +	if (ret) {
>> +		dev_err(dev, "Unable to init display pipe\n");
>> +		return ret;
>> +	}
>> +
>> +	drm_plane_enable_fb_damage_clips(&priv->pipe.plane);
>> +
>> +	drm_mode_config_reset(drm);
>> +
>> +	ret = drm_dev_register(drm, 0);
>> +	if (ret) {
>> +		dev_err(dev, "Failed to register DRM driver\n");
>> +		return ret;
>> +	}
>> +
>> +	ret = devm_add_action_or_reset(dev, tiny_dsi_remove, drm);
>> +	if (ret)
>> +		return ret;
>> +
>> +	drm_fbdev_generic_setup(drm, 0);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(mipi_dsi_register_tiny_driver);
>> +
>> +MODULE_DESCRIPTION("DSI/DBI TinyDRM driver");
>> +MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
>> +MODULE_LICENSE("GPL");
>> diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
>> index 65d2961fc054..0c2589a55df6 100644
>> --- a/include/drm/drm_mipi_dsi.h
>> +++ b/include/drm/drm_mipi_dsi.h
>> @@ -10,6 +10,7 @@
>>   #define __DRM_MIPI_DSI_H__
>>   \x7f  #include <linux/device.h>
>> +#include <linux/of_graph.h>
>>   \x7f  struct mipi_dsi_host;
>>   struct mipi_dsi_device;
>> @@ -337,4 +338,22 @@ void mipi_dsi_driver_unregister(struct 
>> mipi_dsi_driver *driver);
>>   	module_driver(__mipi_dsi_driver, mipi_dsi_driver_register, \
>>   			mipi_dsi_driver_unregister)
>>   \x7f+#if IS_ENABLED(CONFIG_TINYDRM_DSI)
>> +int mipi_dsi_register_tiny_driver(struct mipi_dsi_device *dsi);
>> +#else
>> +static inline int mipi_dsi_register_tiny_driver(struct 
>> mipi_dsi_device *dsi)
>> +{
>> +	return 0;
>> +}
>> +#endif
>> +
>> +static inline int mipi_dsi_maybe_register_tiny_driver(struct 
>> mipi_dsi_device *dsi)
>> +{
>> +	/* Register the TinyDRM DSI/DBI driver if the panel has no 
>> controller */
>> +	if (!of_graph_get_port_by_id(dsi->dev.of_node, 0))
>> +		return mipi_dsi_register_tiny_driver(dsi);
>> +
>> +	return 0;
>> +}
>> +
>>   #endif /* __DRM_MIPI_DSI__ */


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