Message-ID: <b8cf3174b993b335b6929b269a6b6cbd@mainlining.org>
Date: Wed, 17 Apr 2024 17:46:00 +0200
From: David Wronek <david@...nlining.org>
To: Marijn Suijten <marijn.suijten@...ainline.org>
Cc: Neil Armstrong <neil.armstrong@...aro.org>, Jessica Zhang
 <quic_jesszhan@...cinc.com>, Sam Ravnborg <sam@...nborg.org>, Daniel Vetter
 <daniel@...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>, Konrad Dybcio <konradybcio@...nel.org>,
 dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, ~postmarketos/upstreaming@...ts.sr.ht,
 phone-devel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] drm/panel: Add driver for EDO RM69380 OLED panel

W dniu 2024-04-16 22:52, Marijn Suijten napisał(a):
> On 2024-04-16 20:30:49, David Wronek wrote:
>> Add support for the 2560x1600@...z OLED panel by EDO bundled with a
>> Raydium RM69380 controller, as found on the Lenovo Xiaoxin Pad Pro 
>> 2021.
>> 
>> Signed-off-by: David Wronek <david@...nlining.org>
>> ---
>>  drivers/gpu/drm/panel/Kconfig                 |  14 +
>>  drivers/gpu/drm/panel/Makefile                |   1 +
>>  drivers/gpu/drm/panel/panel-raydium-rm69380.c | 367 
>> ++++++++++++++++++++++++++
>>  3 files changed, 382 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/panel/Kconfig 
>> b/drivers/gpu/drm/panel/Kconfig
>> index 154f5bf82980..5b3eeb93b1a2 100644
>> --- a/drivers/gpu/drm/panel/Kconfig
>> +++ b/drivers/gpu/drm/panel/Kconfig
>> @@ -542,6 +542,20 @@ config DRM_PANEL_RAYDIUM_RM692E5
>>  	  Say Y here if you want to enable support for Raydium RM692E5-based
>>  	  display panels, such as the one found in the Fairphone 5 
>> smartphone.
>> 
>> +config DRM_PANEL_RAYDIUM_RM69380
>> +	tristate "Raydium RM69380-based DSI panel"
>> +	depends on BACKLIGHT_CLASS_DEVICE
>> +	depends on DRM_DISPLAY_DP_HELPER
> 
> "DRM DisplayPort helpers"
> 
> But you said that this is a DSI device?
> 
> Looking in -next from yesterday, Raydium-RM692E5 and Visionox-R66451 
> get this
> wrong as well.
> 
>> +	depends on DRM_DISPLAY_HELPER
> 
> This also looks unused?  The only helpers in the non-DP non-HDMI helper 
> points
> to more DP AUX code.
> 
>> +	depends on DRM_MIPI_DSI
>> +	depends on OF
> 
> As I've shown in the SOFEF00 cleanup patch, devm_gpiod_get() is used 
> which is
> behind GPIOLIB.  This should probably be a dependency.
> 
>> +	help
>> +	  Say Y here if you want to enable support for Raydium RM69380-based
>> +	  display panels.
>> +
>> +	  This panel controller can be found in the Lenovo Xiaoxin Pad Pro 
>> 2021
>> +	  in combination with an EDO OLED panel.
>> +
>>  config DRM_PANEL_RONBO_RB070D30
>>  	tristate "Ronbo Electronics RB070D30 panel"
>>  	depends on OF
>> diff --git a/drivers/gpu/drm/panel/Makefile 
>> b/drivers/gpu/drm/panel/Makefile
>> index 24a02655d726..e2a2807d4ef0 100644
>> --- a/drivers/gpu/drm/panel/Makefile
>> +++ b/drivers/gpu/drm/panel/Makefile
>> @@ -55,6 +55,7 @@ obj-$(CONFIG_DRM_PANEL_RASPBERRYPI_TOUCHSCREEN) += 
>> panel-raspberrypi-touchscreen
>>  obj-$(CONFIG_DRM_PANEL_RAYDIUM_RM67191) += panel-raydium-rm67191.o
>>  obj-$(CONFIG_DRM_PANEL_RAYDIUM_RM68200) += panel-raydium-rm68200.o
>>  obj-$(CONFIG_DRM_PANEL_RAYDIUM_RM692E5) += panel-raydium-rm692e5.o
>> +obj-$(CONFIG_DRM_PANEL_RAYDIUM_RM69380) += panel-raydium-rm69380.o
>>  obj-$(CONFIG_DRM_PANEL_RONBO_RB070D30) += panel-ronbo-rb070d30.o
>>  obj-$(CONFIG_DRM_PANEL_SAMSUNG_ATNA33XC20) += 
>> panel-samsung-atna33xc20.o
>>  obj-$(CONFIG_DRM_PANEL_SAMSUNG_DB7430) += panel-samsung-db7430.o
>> diff --git a/drivers/gpu/drm/panel/panel-raydium-rm69380.c 
>> b/drivers/gpu/drm/panel/panel-raydium-rm69380.c
>> new file mode 100644
>> index 000000000000..f89230c969b7
>> --- /dev/null
>> +++ b/drivers/gpu/drm/panel/panel-raydium-rm69380.c
>> @@ -0,0 +1,367 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Generated with linux-mdss-dsi-panel-driver-generator from vendor 
>> device tree.
>> + * Copyright (c) 2024 David Wronek <david@...nlining.org>
>> + */
>> +
>> +#include <linux/backlight.h>
>> +#include <linux/delay.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>> +#include <linux/of_graph.h>
>> +#include <linux/regulator/consumer.h>
>> +
>> +#include <video/mipi_display.h>
>> +
>> +#include <drm/drm_mipi_dsi.h>
>> +#include <drm/drm_modes.h>
>> +#include <drm/drm_panel.h>
>> +#include <drm/drm_probe_helper.h>
>> +
>> +struct rm69380_panel {
>> +	struct drm_panel panel;
>> +	struct mipi_dsi_device *dsi[2];
>> +	struct regulator_bulk_data supplies[2];
>> +	struct gpio_desc *reset_gpio;
>> +};
>> +
>> +static inline
>> +struct rm69380_panel *to_rm69380_panel(struct drm_panel *panel)
>> +{
>> +	return container_of(panel, struct rm69380_panel, panel);
>> +}
>> +
>> +static void rm69380_reset(struct rm69380_panel *ctx)
>> +{
>> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
>> +	usleep_range(15000, 16000);
>> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
>> +	usleep_range(10000, 11000);
>> +	gpiod_set_value_cansleep(ctx->reset_gpio, 0);
>> +	msleep(30);
>> +}
>> +
>> +static int rm69380_on(struct rm69380_panel *ctx)
>> +{
>> +	struct mipi_dsi_device *dsi = ctx->dsi[0];
>> +	struct device *dev = &dsi->dev;
>> +	int ret;
>> +
>> +	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
>> +	if (ctx->dsi[1])
>> +		ctx->dsi[1]->mode_flags |= MIPI_DSI_MODE_LPM;
>> +
>> +	mipi_dsi_dcs_write_seq(dsi, 0xfe, 0xd4);
>> +	mipi_dsi_dcs_write_seq(dsi, 0x00, 0x80);
> 
> Is this MIPI_DCS_NOP?  Strange to see that with a parameter.
> 

I don't think it is. 0xfe is the command to switch the 'manufacture 
command set'. As you can see, it switches to a different MCS right after 
this one. Given that I don't have a datasheet for this perticular driver 
IC, I can't be absolutely certain, but considering that the drivers for 
rm67191 and rm68200 are defining 0xfe as the command to switch the 
commands sets, it's probably the same here.

>> +	mipi_dsi_dcs_write_seq(dsi, 0xfe, 0xd0);
>> +	mipi_dsi_dcs_write_seq(dsi, 0x48, 0x00);
>> +	mipi_dsi_dcs_write_seq(dsi, 0xfe, 0x26);
>> +	mipi_dsi_dcs_write_seq(dsi, 0x75, 0x3f);
>> +	mipi_dsi_dcs_write_seq(dsi, 0x1d, 0x1a);
>> +	mipi_dsi_dcs_write_seq(dsi, 0xfe, 0x00);
>> +	mipi_dsi_dcs_write_seq(dsi, MIPI_DCS_WRITE_CONTROL_DISPLAY, 0x28);
> 
> Separate from this patch, I feel like we should document these bits.  
> Their
> meaning might be defined by a paywall, intersecting a few downstream 
> DTS with
> DCS commands makes it instantly clear what each bit means.
> 
>> +	mipi_dsi_dcs_write_seq(dsi, 0xc2, 0x08);
>> +
>> +	ret = mipi_dsi_dcs_set_tear_on(dsi, MIPI_DSI_DCS_TEAR_MODE_VBLANK);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to set tear on: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = mipi_dsi_dcs_set_display_brightness(dsi, 0x7ff);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to set display brightness: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	ret = mipi_dsi_dcs_exit_sleep_mode(dsi);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to exit sleep mode: %d\n", ret);
>> +		return ret;
>> +	}
>> +	msleep(20);
>> +
>> +	ret = mipi_dsi_dcs_set_display_on(dsi);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to set display on: %d\n", ret);
>> +		return ret;
>> +	}
>> +	msleep(36);
>> +
>> +	return 0;
>> +}
>> +
>> +static int rm69380_off(struct rm69380_panel *ctx)
>> +{
>> +	struct mipi_dsi_device *dsi = ctx->dsi[0];
>> +	struct device *dev = &dsi->dev;
>> +	int ret;
>> +
>> +	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
>> +	if (ctx->dsi[1])
>> +		ctx->dsi[1]->mode_flags &= ~MIPI_DSI_MODE_LPM;
>> +
>> +	ret = mipi_dsi_dcs_set_display_off(dsi);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to set display off: %d\n", ret);
>> +		return ret;
>> +	}
>> +	msleep(35);
>> +
>> +	ret = mipi_dsi_dcs_enter_sleep_mode(dsi);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to enter sleep mode: %d\n", ret);
>> +		return ret;
>> +	}
>> +	msleep(20);
>> +
>> +	return 0;
>> +}
>> +
>> +static int rm69380_prepare(struct drm_panel *panel)
>> +{
>> +	struct rm69380_panel *ctx = to_rm69380_panel(panel);
>> +	struct device *dev = &ctx->dsi[0]->dev;
>> +	int ret;
>> +
>> +	ret = regulator_bulk_enable(ARRAY_SIZE(ctx->supplies), 
>> ctx->supplies);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to enable regulators: %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	rm69380_reset(ctx);
>> +
>> +	ret = rm69380_on(ctx);
>> +	if (ret < 0) {
>> +		dev_err(dev, "Failed to initialize panel: %d\n", ret);
>> +		gpiod_set_value_cansleep(ctx->reset_gpio, 1);
>> +		regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int rm69380_unprepare(struct drm_panel *panel)
>> +{
>> +	struct rm69380_panel *ctx = to_rm69380_panel(panel);
>> +	struct device *dev = &ctx->dsi[0]->dev;
>> +	int ret;
>> +
>> +	ret = rm69380_off(ctx);
>> +	if (ret < 0)
>> +		dev_err(dev, "Failed to un-initialize panel: %d\n", ret);
>> +
>> +	gpiod_set_value_cansleep(ctx->reset_gpio, 1);
>> +	regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct drm_display_mode rm69380_mode = {
>> +	.clock = (2560 + 32 + 12 + 38) * (1600 + 20 + 4 + 8) * 90 / 1000,
>> +	.hdisplay = 2560,
>> +	.hsync_start = 2560 + 32,
>> +	.hsync_end = 2560 + 32 + 12,
>> +	.htotal = 2560 + 32 + 12 + 38,
>> +	.vdisplay = 1600,
>> +	.vsync_start = 1600 + 20,
>> +	.vsync_end = 1600 + 20 + 4,
>> +	.vtotal = 1600 + 20 + 4 + 8,
>> +	.width_mm = 248,
>> +	.height_mm = 155,
>> +	.type = DRM_MODE_TYPE_DRIVER,
>> +};
>> +
>> +static int rm69380_get_modes(struct drm_panel *panel,
>> +					struct drm_connector *connector)
>> +{
>> +	return drm_connector_helper_get_modes_fixed(connector, 
>> &rm69380_mode);
>> +}
>> +
>> +static const struct drm_panel_funcs rm69380_panel_funcs = {
>> +	.prepare = rm69380_prepare,
>> +	.unprepare = rm69380_unprepare,
>> +	.get_modes = rm69380_get_modes,
>> +};
>> +
>> +static int rm69380_bl_update_status(struct backlight_device *bl)
>> +{
>> +	struct mipi_dsi_device *dsi = bl_get_data(bl);
>> +	u16 brightness = backlight_get_brightness(bl);
>> +	int ret;
>> +
>> +	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
>> +
>> +	ret = mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
>> +
>> +	return 0;
>> +}
>> +
>> +static int rm69380_bl_get_brightness(struct backlight_device *bl)
>> +{
>> +	struct mipi_dsi_device *dsi = bl_get_data(bl);
>> +	u16 brightness;
>> +	int ret;
>> +
>> +	dsi->mode_flags &= ~MIPI_DSI_MODE_LPM;
>> +
>> +	ret = mipi_dsi_dcs_get_display_brightness_large(dsi, &brightness);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	dsi->mode_flags |= MIPI_DSI_MODE_LPM;
>> +
>> +	return brightness;
>> +}
>> +
>> +static const struct backlight_ops rm69380_bl_ops = {
>> +	.update_status = rm69380_bl_update_status,
>> +	.get_brightness = rm69380_bl_get_brightness,
>> +};
>> +
>> +static struct backlight_device *
>> +rm69380_create_backlight(struct mipi_dsi_device *dsi)
>> +{
>> +	struct device *dev = &dsi->dev;
>> +	const struct backlight_properties props = {
>> +		.type = BACKLIGHT_RAW,
>> +		.brightness = 2047,
> 
> Might be nice to reduce the init brightness to something lower, like 
> 1023 or
> 511?  But also drop the brightness call in _on().
> 

Good call, the OLED panel on my tablet likes to burn-in (temporarily) 
really fast on high brightness. I did however notice that at least on an 
Arch Linux ARM rootfs, the brightness is being remembered and restored 
upon boot.

>> +		.max_brightness = 2047,
>> +	};
>> +
>> +	return devm_backlight_device_register(dev, dev_name(dev), dev, dsi,
>> +					      &rm69380_bl_ops, &props);
>> +}
>> +
>> +static int rm69380_probe(struct mipi_dsi_device *dsi)
>> +{
>> +	struct mipi_dsi_host *dsi_sec_host;
>> +	struct rm69380_panel *ctx;
>> +	struct device *dev = &dsi->dev;
>> +	struct device_node *dsi_sec;
>> +	int ret, i;
>> +
>> +	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
>> +	if (!ctx)
>> +		return -ENOMEM;
>> +
>> +	ctx->supplies[0].supply = "vddio";
>> +	ctx->supplies[1].supply = "avdd";
>> +	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ctx->supplies),
>> +				      ctx->supplies);
>> +	if (ret < 0)
>> +		return dev_err_probe(dev, ret, "Failed to get regulators\n");
>> +
>> +	ctx->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
>> +	if (IS_ERR(ctx->reset_gpio))
>> +		return dev_err_probe(dev, PTR_ERR(ctx->reset_gpio),
>> +				     "Failed to get reset-gpios\n");
>> +
>> +	dsi_sec = of_graph_get_remote_node(dsi->dev.of_node, 1, -1);
>> +
>> +	if (dsi_sec) {
>> +		const struct mipi_dsi_device_info info = { "RM69380", 0,
>> +							   dsi_sec };
>> +
>> +		dev_dbg(dev, "Using Dual-DSI: found `%s`\n", dsi_sec->name);
>> +
>> +		dsi_sec_host = of_find_mipi_dsi_host_by_node(dsi_sec);
>> +		of_node_put(dsi_sec);
>> +		if (!dsi_sec_host)
>> +			return dev_err_probe(dev, -EPROBE_DEFER,
>> +					     "Cannot get secondary DSI host\n");
>> +
>> +		ctx->dsi[1] =
>> +			devm_mipi_dsi_device_register_full(dev, dsi_sec_host, &info);
>> +		if (IS_ERR(ctx->dsi[1]))
>> +			return dev_err_probe(dev, PTR_ERR(ctx->dsi[1]),
>> +					     "Cannot get secondary DSI node\n");
>> +
>> +		dev_dbg(dev, "Second DSI name `%s`\n", ctx->dsi[1]->name);
> 
> Let's drop my debug logs :)
> 
>> +		mipi_dsi_set_drvdata(ctx->dsi[1], ctx);
>> +	} else {
>> +		dev_dbg(dev, "Using Single-DSI\n");
>> +	}
>> +
>> +	ctx->dsi[0] = dsi;
>> +	mipi_dsi_set_drvdata(dsi, ctx);
>> +
>> +	drm_panel_init(&ctx->panel, dev, &rm69380_panel_funcs,
>> +		       DRM_MODE_CONNECTOR_DSI);
>> +	ctx->panel.prepare_prev_first = true;
>> +
>> +	ctx->panel.backlight = rm69380_create_backlight(dsi);
>> +	if (IS_ERR(ctx->panel.backlight))
>> +		return dev_err_probe(dev, PTR_ERR(ctx->panel.backlight),
>> +				     "Failed to create backlight\n");
>> +
>> +	drm_panel_add(&ctx->panel);
>> +
>> +	for (i = 0; i < ARRAY_SIZE(ctx->dsi); i++) {
>> +		if (!ctx->dsi[i])
>> +			continue;
>> +
>> +		dev_dbg(&ctx->dsi[i]->dev, "Binding DSI %d\n", i);
> 
> Probably not very useful?
> 
>> +
>> +		ctx->dsi[i]->lanes = 4;
>> +		ctx->dsi[i]->format = MIPI_DSI_FMT_RGB888;
>> +		ctx->dsi[i]->mode_flags = MIPI_DSI_MODE_VIDEO_BURST |
>> +					  MIPI_DSI_CLOCK_NON_CONTINUOUS;
>> +
>> +		ret = mipi_dsi_attach(ctx->dsi[i]);
>> +		if (ret < 0) {
>> +			mipi_dsi_detach(ctx->dsi[i]);
> 
> This isn't sound as written.  If attaching fails, it is likely an error 
> to
> detach the same DSI device.
> 
> The error scenario that Christophe pointed out is when attaching dsi[1]
> fails, in this case you have to detach dsi[0].  But as written in late 
> v2
> review, instead of making complicated logic statements there is a 
> matching
> devm_mipi_dsi_attach() to handle these cleanup scenarios for you.  This 
> should
> also remove the need for mipi_dsi_attach() in the _remove function.
> 
> - Marijn
> 
>> +			drm_panel_remove(&ctx->panel);
>> +			return dev_err_probe(dev, ret,
>> +					     "Failed to attach to DSI%d\n", i);
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static void rm69380_remove(struct mipi_dsi_device *dsi)
>> +{
>> +	struct rm69380_panel *ctx = mipi_dsi_get_drvdata(dsi);
>> +	int i;
>> +	int ret;
>> +
>> +	for (i = 0; i < ARRAY_SIZE(ctx->dsi); i++) {
>> +		if (!ctx->dsi[i])
>> +			continue;
>> +
>> +		ret = mipi_dsi_detach(ctx->dsi[i]);
>> +		if (ret < 0)
>> +			dev_err(&dsi->dev, "Failed to detach from DSI%d host: %d\n", i, 
>> ret);
>> +	}
>> +
>> +	drm_panel_remove(&ctx->panel);
>> +}
>> +
>> +static const struct of_device_id rm69380_of_match[] = {
>> +	{ .compatible = "lenovo,j716f-edo-rm69380" },
>> +	{ /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, rm69380_of_match);
>> +
>> +static struct mipi_dsi_driver rm69380_panel_driver = {
>> +	.probe = rm69380_probe,
>> +	.remove = rm69380_remove,
>> +	.driver = {
>> +		.name = "panel-raydium-rm69380",
>> +		.of_match_table = rm69380_of_match,
>> +	},
>> +};
>> +module_mipi_dsi_driver(rm69380_panel_driver);
>> +
>> +MODULE_AUTHOR("David Wronek <david@...nlining.org");
>> +MODULE_DESCRIPTION("DRM driver for Raydium RM69380-equipped DSI 
>> panels");
>> +MODULE_LICENSE("GPL");
>> 
>> --
>> 2.44.0
>> 

-- 
Best regards,
David Wronek <david@...nlining.org>

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