Message-ID: <9aca40c3-e22a-4d41-bac8-18a7cc8e3e96@nxp.com>
Date: Tue, 5 Aug 2025 10:22:26 +0800
From: Liu Ying <victor.liu@....com>
To: Joseph Guo <qijian.guo@....com>, Andrzej Hajda <andrzej.hajda@...el.com>,
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>,
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, Jessica Zhang
 <quic_jesszhan@...cinc.com>, Thierry Reding <thierry.reding@...il.com>,
 Sam Ravnborg <sam@...nborg.org>
Cc: dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 3/3] drm: bridge: Add waveshare DSI2DPI unit driver

Hi Joseph,

On 08/04/2025, Joseph Guo wrote:
> Waveshare touchscreen consists of a DPI panel and a driver board.
> The waveshare driver board consists of ICN6211 and a MCU to
> convert DSI to DPI and control the backlight.
> This driver treats the MCU and ICN6211 board as a whole unit.
> It can support all resolution waveshare DSI2DPI based panel,
> the timing table should come from 'panel-dpi' panel in the device tree.
> 
> Signed-off-by: Joseph Guo <qijian.guo@....com>

For next version, you may add:
Suggested-by: Liu Ying <victor.liu@....com>

> ---
>  drivers/gpu/drm/bridge/Kconfig         |  11 ++
>  drivers/gpu/drm/bridge/Makefile        |   1 +
>  drivers/gpu/drm/bridge/waveshare-dsi.c | 210 +++++++++++++++++++++++++++++++++
>  3 files changed, 222 insertions(+)

This patch doesn't apply to drm-misc-next cleanly.  I see conflicts in Kconfig
and Makefile.  It seems that you generate the patch series based on NXP down
stream kernel instead of the upstream kernel.

> 
> diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
> index cb3b797fcea1c73e83c9187fef6582296b340305..26fec25c61ed7d950c094e0224f1196946079485 100644
> --- a/drivers/gpu/drm/bridge/Kconfig
> +++ b/drivers/gpu/drm/bridge/Kconfig
> @@ -472,4 +472,15 @@ config DRM_ITE_IT6161
>  	help
>  	  ITE IT6161 bridge chip driver.
>  
> +config DRM_WAVESHARE_BRIDGE

Sort the config names alphabetically.

> +	tristate "Waveshare DSI bridge"

depends on BACKLIGHT_CLASS_DEVICE

> +	depends on OF
> +	select DRM_PANEL_BRIDGE
> +	select DRM_KMS_HELPER
> +	select DRM_MIPI_DSI
> +	select REGMAP_I2C
> +	help
> +	  Driver for waveshare DSI to DPI bridge board.
> +	  Please say Y if you have such hardware
> +
>  endmenu
> diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile
> index d1db90688a150fdc3a5fd40acebe740798c452b0..3caa4d8f71675804328aa5a51ec67b2587938621 100644
> --- a/drivers/gpu/drm/bridge/Makefile
> +++ b/drivers/gpu/drm/bridge/Makefile
> @@ -48,3 +48,4 @@ obj-$(CONFIG_DRM_ITE_IT6263) += it6263.o
>  obj-$(CONFIG_DRM_ITE_IT6161) += it6161.o
>  obj-$(CONFIG_DRM_SEC_MIPI_DSIM) += sec-dsim.o
>  obj-$(CONFIG_DRM_NXP_SEIKO_43WVFIG) += nxp-seiko-43wvfig.o
> +obj-$(CONFIG_DRM_WAVESHARE_BRIDGE) += waveshare-dsi.o

Sort the config names alphabetically with the best effort.

> diff --git a/drivers/gpu/drm/bridge/waveshare-dsi.c b/drivers/gpu/drm/bridge/waveshare-dsi.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..efb3a2fc501b5725b02f49862526d1704a3a4b7b
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/waveshare-dsi.c
> @@ -0,0 +1,210 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + *  Copyright 2025 NXP

Nit: Drop a space between * and C.

> + * Based on panel-raspberrypi-touchscreen by Broadcom
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_graph.h>
> +#include <linux/regmap.h>
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_print.h>
> +
> +struct ws_bridge {
> +	struct drm_bridge bridge;
> +	struct drm_bridge *next_bridge;
> +	struct backlight_device *backlight;
> +	struct device *dev;
> +	struct regmap *reg_map;
> +};
> +
> +static const struct regmap_config ws_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = 0xff,
> +	.disable_debugfs = true,

drivers/gpu/drm/bridge/waveshare-dsi.c:34:10: error: ‘const struct regmap_config’ has no member named ‘disable_debugfs’
   34 |         .disable_debugfs = true,
      |          ^~~~~~~~~~~~~~~

> +};
> +
> +static struct ws_bridge *bridge_to_ws_bridge(struct drm_bridge *bridge)
> +{
> +	return container_of(bridge, struct ws_bridge, bridge);
> +}
> +
> +static int ws_bridge_attach_dsi(struct ws_bridge *ws)
> +{
> +	struct device_node *dsi_host_node;
> +	struct mipi_dsi_host *host;
> +	struct mipi_dsi_device *dsi;
> +	const struct mipi_dsi_device_info info = {
> +		.type = "ws-bridge",
> +		.channel = 0,
> +		.node = NULL,
> +	};
> +	struct device *dev = ws->dev;
> +	int ret;

Nit: Sort these variables in reverse Christmas tree fashion.

> +
> +	dsi_host_node = of_graph_get_remote_node(dev->of_node, 0, 0);
> +	if (!dsi_host_node) {
> +		dev_err(dev, "Failed to get remote port\n");
> +		return -ENODEV;
> +	}
> +
> +	host = of_find_mipi_dsi_host_by_node(dsi_host_node);
> +

Nit: Drop this blank line.

> +	of_node_put(dsi_host_node);
> +	if (!host)
> +		return dev_err_probe(dev, -EPROBE_DEFER, "Failed to find dsi_host\n");
> +
> +	dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
> +

Ditto.

> +	if (IS_ERR(dsi))
> +		return dev_err_probe(dev, PTR_ERR(dsi), "Failed to create dsi device\n");
> +
> +	dsi->mode_flags = MIPI_DSI_MODE_VIDEO_HSE | MIPI_DSI_MODE_VIDEO |
> +			  MIPI_DSI_CLOCK_NON_CONTINUOUS;
> +	dsi->format = MIPI_DSI_FMT_RGB888;
> +	dsi->lanes = 2;
> +
> +	ret = devm_mipi_dsi_attach(dev, dsi);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to attach dsi to host\n");
> +
> +	return 0;
> +}
> +
> +static int ws_bridge_bridge_attach(struct drm_bridge *bridge,
> +				   enum drm_bridge_attach_flags flags)

drivers/gpu/drm/bridge/waveshare-dsi.c:117:19: error: initialization of ‘int (*)(struct drm_bridge *, struct drm_encoder *, enum drm_bridge_attach_flags)’ from incompatible pointer type ‘int (*)(struct drm_bridge *, enum drm_bridge_attach_flags)’ [-Werror=incompatible-pointer-types]
  117 |         .attach = ws_bridge_bridge_attach,
      |                   ^~~~~~~~~~~~~~~~~~~~~~~

> +{
> +	struct ws_bridge *ws = bridge_to_ws_bridge(bridge);
> +	int ret;
> +
> +	ret = ws_bridge_attach_dsi(ws);
> +	if (ret)
> +		return ret;
> +
> +	return drm_bridge_attach(ws->bridge.encoder, ws->next_bridge,
> +				 &ws->bridge, flags);
> +}
> +
> +static void ws_bridge_bridge_enable(struct drm_bridge *bridge)
> +{
> +	struct ws_bridge *ws = bridge_to_ws_bridge(bridge);
> +
> +	regmap_write(ws->reg_map, 0xad, 0x01);
> +	backlight_enable(ws->backlight);
> +}
> +
> +static void ws_bridge_bridge_disable(struct drm_bridge *bridge)
> +{
> +	struct ws_bridge *ws = bridge_to_ws_bridge(bridge);
> +
> +	backlight_disable(ws->backlight);
> +	regmap_write(ws->reg_map, 0xad, 0x00);
> +}
> +
> +static const struct drm_bridge_funcs ws_bridge_bridge_funcs = {
> +	.enable = ws_bridge_bridge_enable,
> +	.disable = ws_bridge_bridge_disable,
> +	.attach = ws_bridge_bridge_attach,
> +};
> +
> +static int ws_bridge_bl_update_status(struct backlight_device *bl)
> +{
> +	struct ws_bridge *ws = bl_get_data(bl);
> +
> +	regmap_write(ws->reg_map, 0xab, 0xff - backlight_get_brightness(bl));
> +	regmap_write(ws->reg_map, 0xaa, 0x01);
> +
> +	return 0;
> +}
> +
> +static const struct backlight_ops ws_bridge_bl_ops = {
> +	.update_status = ws_bridge_bl_update_status,
> +};
> +
> +static struct backlight_device *ws_bridge_create_backlight(struct ws_bridge *ws)
> +{
> +	struct device *dev = ws->dev;
> +	const struct backlight_properties props = {
> +		.type = BACKLIGHT_RAW,
> +		.brightness = 255,
> +		.max_brightness = 255,
> +	};

Nit: Sort these variables in reverse Christmas tree fashion.

> +
> +	return devm_backlight_device_register(dev, dev_name(dev), dev, ws,
> +					      &ws_bridge_bl_ops, &props);
> +}
> +
> +static int ws_bridge_probe(struct i2c_client *i2c)
> +{
> +	struct device *dev = &i2c->dev;
> +	struct ws_bridge *ws;
> +	struct drm_panel *panel;
> +	int ret;
> +	struct backlight_device *backlight;

Ditto.

> +
> +	ws = devm_kzalloc(dev, sizeof(*ws), GFP_KERNEL);

Recently upstream bridge drivers were changed to use devm_drm_bridge_alloc()
to allocate the main structure which contains the DRM bridge member.
devm_kzalloc() is no more allowed to be used.

> +	if (!ws)
> +		return -ENOMEM;
> +
> +	ws->dev = dev;
> +
> +	ws->reg_map = devm_regmap_init_i2c(i2c, &ws_regmap_config);
> +	if (IS_ERR(ws->reg_map))
> +		return dev_err_probe(dev, PTR_ERR(ws->reg_map), "Failed to allocate regmap\n");
> +
> +	ret = drm_of_find_panel_or_bridge(dev->of_node, 1, -1, &panel, NULL);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "Failed to find remote panel\n");
> +
> +	ws->next_bridge = devm_drm_panel_bridge_add(dev, panel);
> +	if (IS_ERR(ws->next_bridge))
> +		return PTR_ERR(ws->next_bridge);
> +
> +	ws->backlight = ws_bridge_create_backlight(ws);
> +	if (IS_ERR(backlight)) {
> +		ret = PTR_ERR(backlight);
> +		dev_err(dev, "Failed to create backlight: %d\n", ret);
> +		return ret;
> +	}
> +
> +	regmap_write(ws->reg_map, 0xc0, 0x01);
> +	regmap_write(ws->reg_map, 0xc2, 0x01);
> +	regmap_write(ws->reg_map, 0xac, 0x01);
> +
> +	ws->bridge.funcs = &ws_bridge_bridge_funcs;
> +	ws->bridge.type = DRM_MODE_CONNECTOR_DPI;
> +	ws->bridge.of_node = dev->of_node;
> +	devm_drm_bridge_add(dev, &ws->bridge);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id ws_bridge_of_ids[] = {
> +	{.compatible = "waveshare,dsi2dpi",},
> +	{ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, ws_bridge_of_ids);
> +
> +static struct i2c_driver ws_bridge_driver = {
> +	.driver = {
> +		.name = "ws_dsi2dpi",
> +		.of_match_table = ws_bridge_of_ids,
> +	},
> +	.probe = ws_bridge_probe,
> +};
> +module_i2c_driver(ws_bridge_driver);
> +
> +MODULE_AUTHOR("Joseph Guo <qijian.guo@....com>");
> +MODULE_DESCRIPTION("Waveshare DSI2DPI bridge driver");
> +MODULE_LICENSE("GPL");
> 


-- 
Regards,
Liu Ying

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