Message-ID: <bfd59539-fc71-4994-ca33-f5fd3851243b@suse.de>
Date:   Mon, 2 Aug 2021 17:08:08 +0200
From:   Thomas Zimmermann <tzimmermann@...e.de>
To:     Icenowy Zheng <icenowy@...eed.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>
Cc:     dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] drm/tiny: add simple-dbi driver

Hi

Am 02.08.21 um 08:35 schrieb Icenowy Zheng:
> Add a driver for generic MIPI DBI panels initialized with MIPI DCS
> commands.
> 
> Currently a ST7789V-based panel is added to it. This panel has its
> configuration pre-programmed into the controller, so no vendor-specific
> configuration is needed.
> 
> Signed-off-by: Icenowy Zheng <icenowy@...eed.com>
> ---
>   drivers/gpu/drm/tiny/Kconfig      |  12 ++
>   drivers/gpu/drm/tiny/Makefile     |   1 +
>   drivers/gpu/drm/tiny/simple-dbi.c | 244 ++++++++++++++++++++++++++++++
>   3 files changed, 257 insertions(+)
>   create mode 100644 drivers/gpu/drm/tiny/simple-dbi.c
> 
> diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
> index d31be274a2bd..6cfc57b68a46 100644
> --- a/drivers/gpu/drm/tiny/Kconfig
> +++ b/drivers/gpu/drm/tiny/Kconfig
> @@ -144,6 +144,18 @@ config TINYDRM_REPAPER
>   
>   	  If M is selected the module will be called repaper.
>   
> +config TINYDRM_SIMPLE_DBI
> +	tristate "DRM support for generic MIPI DBI panels"
> +	depends on DRM && SPI
> +	select DRM_KMS_HELPER
> +	select DRM_KMS_CMA_HELPER
> +	select DRM_MIPI_DBI
> +	help
> +	  DRM driver for generic DBI panels that are MIPI DCS compatible
> +	  and needs no vendor-specific setup commands.
> +
> +	  If M is selected the module will be called simple-dbi.
> +
>   config TINYDRM_ST7586
>   	tristate "DRM support for Sitronix ST7586 display panels"
>   	depends on DRM && SPI
> diff --git a/drivers/gpu/drm/tiny/Makefile b/drivers/gpu/drm/tiny/Makefile
> index e09942895c77..2553de651aa3 100644
> --- a/drivers/gpu/drm/tiny/Makefile
> +++ b/drivers/gpu/drm/tiny/Makefile
> @@ -13,3 +13,4 @@ obj-$(CONFIG_TINYDRM_MI0283QT)		+= mi0283qt.o
>   obj-$(CONFIG_TINYDRM_REPAPER)		+= repaper.o
>   obj-$(CONFIG_TINYDRM_ST7586)		+= st7586.o
>   obj-$(CONFIG_TINYDRM_ST7735R)		+= st7735r.o
> +obj-$(CONFIG_TINYDRM_SIMPLE_DBI)	+= simple-dbi.o
> diff --git a/drivers/gpu/drm/tiny/simple-dbi.c b/drivers/gpu/drm/tiny/simple-dbi.c
> new file mode 100644
> index 000000000000..2b207e43d500
> --- /dev/null
> +++ b/drivers/gpu/drm/tiny/simple-dbi.c
> @@ -0,0 +1,244 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * DRM driver for display panels with configuration preset and needs only
> + * standard MIPI DCS commands to bring up.
> + *
> + * Copyright (C) 2021 Sipeed
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/delay.h>
> +#include <linux/dma-buf.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/property.h>
> +#include <linux/spi/spi.h>
> +#include <video/mipi_display.h>
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_drv.h>
> +#include <drm/drm_fb_helper.h>
> +#include <drm/drm_gem_atomic_helper.h>
> +#include <drm/drm_gem_cma_helper.h>
> +#include <drm/drm_managed.h>
> +#include <drm/drm_mipi_dbi.h>
> +
> +#define MIPI_DCS_ADDRESS_MODE_BGR		BIT(3)
> +#define MIPI_DCS_ADDRESS_MODE_REVERSE		BIT(5)
> +#define MIPI_DCS_ADDRESS_MODE_RTL		BIT(6)
> +#define MIPI_DCS_ADDRESS_MODE_BTT		BIT(7)
> +
> +struct simple_dbi_cfg {
> +	const struct drm_display_mode mode;
> +	unsigned int left_offset;
> +	unsigned int top_offset;
> +	bool inverted;
> +	bool write_only;
> +	bool bgr;
> +	bool right_to_left;
> +	bool bottom_to_top;
> +};
> +
> +struct simple_dbi_priv {
> +	struct mipi_dbi_dev dbidev;	/* Must be first for .release() */

Which release?

> +	const struct simple_dbi_cfg *cfg;
> +};
> +
> +static void simple_dbi_pipe_enable(struct drm_simple_display_pipe *pipe,
> +				struct drm_crtc_state *crtc_state,
> +				struct drm_plane_state *plane_state)
> +{
> +	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
> +	struct simple_dbi_priv *priv = container_of(dbidev,
> +						    struct simple_dbi_priv,
> +						    dbidev);
> +	struct mipi_dbi *dbi = &dbidev->dbi;
> +	int ret, idx;
> +	u8 addr_mode = 0x00;
> +
> +	if (!drm_dev_enter(pipe->crtc.dev, &idx))
> +		return;
> +
> +	DRM_DEBUG_KMS("\n");

I'm not a friend of such debugging statements. If you absolutely want to 
keep it, rather use drm_dbg_kms().

> +
> +	ret = mipi_dbi_poweron_reset(dbidev);
> +	if (ret)
> +		goto out_exit;
> +
> +	mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
> +	msleep(5);
> +
> +	/* Currently tinydrm supports 16bit only now */
> +	mipi_dbi_command(dbi, MIPI_DCS_SET_PIXEL_FORMAT,
> +			 MIPI_DCS_PIXEL_FMT_16BIT);
> +
> +	if (priv->cfg->inverted)
> +		mipi_dbi_command(dbi, MIPI_DCS_ENTER_INVERT_MODE);
> +	else
> +		mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
> +
> +	if (priv->cfg->bgr)
> +		addr_mode |= MIPI_DCS_ADDRESS_MODE_BGR;
> +
> +	if (priv->cfg->right_to_left)
> +		addr_mode |= MIPI_DCS_ADDRESS_MODE_RTL;
> +
> +	if (priv->cfg->bottom_to_top)
> +		addr_mode |= MIPI_DCS_ADDRESS_MODE_BTT;
> +
> +	switch (dbidev->rotation) {
> +	default:
> +		break;
> +	case 90:
> +		addr_mode ^= MIPI_DCS_ADDRESS_MODE_REVERSE;
> +		addr_mode ^= MIPI_DCS_ADDRESS_MODE_RTL;
> +		break;
> +	case 180:
> +		addr_mode ^= MIPI_DCS_ADDRESS_MODE_RTL;
> +		addr_mode ^= MIPI_DCS_ADDRESS_MODE_BTT;
> +		break;
> +	case 270:
> +		addr_mode ^= MIPI_DCS_ADDRESS_MODE_REVERSE;
> +		addr_mode ^= MIPI_DCS_ADDRESS_MODE_BTT;
> +		break;
> +	}
> +
> +	mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
> +
> +	mipi_dbi_command(dbi, MIPI_DCS_ENTER_NORMAL_MODE);
> +
> +	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
> +
> +	mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
> +out_exit:
> +	drm_dev_exit(idx);
> +}
> +
> +static const struct drm_simple_display_pipe_funcs simple_dbi_pipe_funcs = {
> +	.enable		= simple_dbi_pipe_enable,
> +	.disable	= mipi_dbi_pipe_disable,
> +	.update		= mipi_dbi_pipe_update,
> +	.prepare_fb	= drm_gem_simple_display_pipe_prepare_fb,
> +};
> +
> +static const struct simple_dbi_cfg zsx154_b1206_cfg = {
> +	.mode		= { DRM_SIMPLE_MODE(240, 240, 28, 28) },
> +	.inverted	= true,
> +	.write_only	= true,
> +};
> +
> +DEFINE_DRM_GEM_CMA_FOPS(simple_dbi_fops);
> +
> +static const struct drm_driver simple_dbi_driver = {
> +	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
> +	.fops			= &simple_dbi_fops,
> +	DRM_GEM_CMA_DRIVER_OPS_VMAP,
> +	.debugfs_init		= mipi_dbi_debugfs_init,
> +	.name			= "simple-dbi",
> +	.desc			= "Generic MIPI-DCS compatible DBI panel",
> +	.date			= "20210723",
> +	.major			= 1,
> +	.minor			= 0,
> +};
> +
> +static const struct of_device_id simple_dbi_of_match[] = {
> +	{ .compatible = "zsx,zsx154-b1206", .data = &zsx154_b1206_cfg },
> +	{ },
> +}
> +MODULE_DEVICE_TABLE(of, simple_dbi_of_match);
> +
> +static int simple_dbi_probe(struct spi_device *spi)
> +{
> +	struct device *dev = &spi->dev;
> +	const struct simple_dbi_cfg *cfg;
> +	struct mipi_dbi_dev *dbidev;
> +	struct simple_dbi_priv *priv;
> +	struct drm_device *drm;
> +	struct mipi_dbi *dbi;
> +	struct gpio_desc *dc;
> +	u32 rotation = 0;
> +	int ret;
> +
> +	cfg = device_get_match_data(&spi->dev);
> +	if (!cfg)
> +		cfg = (void *)spi_get_device_id(spi)->driver_data;
> +
> +	priv = devm_drm_dev_alloc(dev, &simple_dbi_driver,
> +				  struct simple_dbi_priv, dbidev.drm);
> +	if (IS_ERR(priv))
> +		return PTR_ERR(priv);
> +
> +	dbidev = &priv->dbidev;
> +	priv->cfg = cfg;
> +
> +	dbi = &dbidev->dbi;
> +	drm = &dbidev->drm;
> +
> +	dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
> +	if (IS_ERR(dbi->reset))
> +		return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get reset GPIO\n");
> +
> +	dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW);
> +	if (IS_ERR(dc))
> +		return dev_err_probe(dev, PTR_ERR(dc), "Failed to get D/C GPIO\n");
> +
> +	dbidev->backlight = devm_of_find_backlight(dev);
> +	if (IS_ERR(dbidev->backlight))
> +		return PTR_ERR(dbidev->backlight);
> +
> +	device_property_read_u32(dev, "rotation", &rotation);
> +
> +	ret = mipi_dbi_spi_init(spi, dbi, dc);
> +	if (ret)
> +		return ret;
> +
> +	if (cfg->write_only)
> +		dbi->read_commands = NULL;
> +
> +	ret = mipi_dbi_dev_init(dbidev, &simple_dbi_pipe_funcs, &cfg->mode,
> +				rotation);
> +	if (ret)
> +		return ret;
> +
> +	drm_mode_config_reset(drm);
> +
> +	ret = drm_dev_register(drm, 0);
> +	if (ret)
> +		return ret;
> +
> +	spi_set_drvdata(spi, drm);

AFAIK dev files are being created during drm_dev_register(). It's 
probably safer to set the drvdata before.

> +
> +	drm_fbdev_generic_setup(drm, 0);
> +
> +	return 0;
> +}
> +
> +static int simple_dbi_remove(struct spi_device *spi)
> +{
> +	struct drm_device *drm = spi_get_drvdata(spi);
> +
> +	drm_dev_unplug(drm);
> +	drm_atomic_helper_shutdown(drm);
> +
> +	return 0;
> +}
> +
> +static void simple_dbi_shutdown(struct spi_device *spi)
> +{
> +	drm_atomic_helper_shutdown(spi_get_drvdata(spi));
> +}
> +
> +static struct spi_driver simple_dbi_spi_driver = {
> +	.driver = {
> +		.name = "simple-dbi",
> +		.of_match_table = simple_dbi_of_match,
> +	},
> +	.probe = simple_dbi_probe,
> +	.remove = simple_dbi_remove,
> +	.shutdown = simple_dbi_shutdown,
> +};
> +module_spi_driver(simple_dbi_spi_driver);
> +
> +MODULE_DESCRIPTION("Simple DBI panel DRM driver");
> +MODULE_AUTHOR("Icenowy Zheng <icenowy@...c.io>");
> +MODULE_LICENSE("GPL");
> 

Trailing blank line. (?)

Best regards
Thomas

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer



Download attachment "OpenPGP_signature" of type "application/pgp-signature" (841 bytes)

Powered by blists - more mailing lists