Hi Noralf,
On Fri, Feb 18, 2022 at 04:11:10PM +0100, Noralf Trønnes wrote:
> Add a driver that will work with most MIPI DBI compatible SPI panels.
> This avoids adding a driver for every new MIPI DBI compatible controller
> that is to be used by Linux. The 'compatible' Device Tree property with
> a '.bin' suffix will be used to load a firmware file that contains the
> controller configuration.
A solution where we have the command sequences as part of the DT-overlay
is IMO a much better way to solve this:
- The users needs to deal only with a single file, so there is less that
goes wrong
- The user need not reading special instructions how to handle a .bin
file, if the overlay is present everything is fine
- The file that contains the command sequences can be properly annotated
with comments
- The people that creates the command sequences has no need for a special
script to create the file for a display - this is all readable ascii.
- Using a DT-overlay the parsing of the DT-overlay can be done by
well-tested functions, no need to invent something new to parse the
file
The idea with a common mipi DBI SPI driver is super, it is the detail
with the .bin file that I am against.
With the above said, a few comments to the current implementation below.
As we know it from you - a very well-written driver.
Sam
> Acked-by: Maxime Ripard <max...@cerno.tech>
> Signed-off-by: Noralf Trønnes <nor...@tronnes.org>
> ---
> MAINTAINERS | 8 +
> drivers/gpu/drm/tiny/Kconfig | 13 +
> drivers/gpu/drm/tiny/Makefile | 1 +
> drivers/gpu/drm/tiny/panel-mipi-dbi.c | 413 ++++++++++++++++++++++++++
> 4 files changed, 435 insertions(+)
> create mode 100644 drivers/gpu/drm/tiny/panel-mipi-dbi.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 8e6e892f99f0..3a0e57f23ad0 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6107,6 +6107,14 @@ T: git git://anongit.freedesktop.org/drm/drm-misc
> F: Documentation/devicetree/bindings/display/multi-inno,mi0283qt.txt
> F: drivers/gpu/drm/tiny/mi0283qt.c
>
> +DRM DRIVER FOR MIPI DBI compatible panels
> +M: Noralf Trønnes <nor...@tronnes.org>
> +S: Maintained
> +W: https://github.com/notro/panel-mipi-dbi/wiki
Nice with a wiki for this, I can see this will grow over time and be a
place to find how to support more panels.
> +T: git git://anongit.freedesktop.org/drm/drm-misc
> +F: Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml
> +F: drivers/gpu/drm/tiny/panel-mipi-dbi.c
> +
> DRM DRIVER FOR MSM ADRENO GPU
> M: Rob Clark <robdcl...@gmail.com>
> M: Sean Paul <s...@poorly.run>
> diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
> index 712e0004e96e..d552e1618da7 100644
> --- a/drivers/gpu/drm/tiny/Kconfig
> +++ b/drivers/gpu/drm/tiny/Kconfig
> @@ -51,6 +51,19 @@ 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.
>
> +config DRM_PANEL_MIPI_DBI
> + tristate "DRM support for MIPI DBI compatible panels"
> + depends on DRM && SPI
> + select DRM_KMS_HELPER
> + select DRM_KMS_CMA_HELPER
This symbol is not present in my drm-misc-next tree (which is a few
weeks old, so it may be newer).
> + select DRM_MIPI_DBI
> + select BACKLIGHT_CLASS_DEVICE
> + help
> + Say Y here if you want to enable support for MIPI DBI compatible
> + panels. The controller command setup can be provided using a
> + firmware file.
Consider adding a link to the wiki here - this may make it easier for
the user to find it.
> + To compile this driver as a module, choose M here.
> +
> config DRM_SIMPLEDRM
> tristate "Simple framebuffer driver"
> depends on DRM && MMU
> diff --git a/drivers/gpu/drm/tiny/Makefile b/drivers/gpu/drm/tiny/Makefile
> index 5d5505d40e7b..1d9d6227e7ab 100644
> --- a/drivers/gpu/drm/tiny/Makefile
> +++ b/drivers/gpu/drm/tiny/Makefile
> @@ -4,6 +4,7 @@ obj-$(CONFIG_DRM_ARCPGU) += arcpgu.o
> obj-$(CONFIG_DRM_BOCHS) += bochs.o
> obj-$(CONFIG_DRM_CIRRUS_QEMU) += cirrus.o
> obj-$(CONFIG_DRM_GM12U320) += gm12u320.o
> +obj-$(CONFIG_DRM_PANEL_MIPI_DBI) += panel-mipi-dbi.o
> obj-$(CONFIG_DRM_SIMPLEDRM) += simpledrm.o
> obj-$(CONFIG_TINYDRM_HX8357D) += hx8357d.o
> obj-$(CONFIG_TINYDRM_ILI9163) += ili9163.o
> diff --git a/drivers/gpu/drm/tiny/panel-mipi-dbi.c
> b/drivers/gpu/drm/tiny/panel-mipi-dbi.c
> new file mode 100644
> index 000000000000..9240fdec38d6
> --- /dev/null
> +++ b/drivers/gpu/drm/tiny/panel-mipi-dbi.c
> @@ -0,0 +1,413 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * DRM driver for MIPI DBI compatible display panels
> + *
> + * Copyright 2022 Noralf Trønnes
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/delay.h>
> +#include <linux/firmware.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/module.h>
> +#include <linux/property.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/spi/spi.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>
> +#include <drm/drm_modeset_helper.h>
> +
> +#include <video/display_timing.h>
> +#include <video/mipi_display.h>
> +#include <video/of_display_timing.h>
> +#include <video/videomode.h>
videomode should not be used in new drivers, it is an fbdev artifact.
But that said - we are still missing a direct display_timing =>
display_mode - so maybe we need it here.
If it is needed Kconfig needs to be extended with:
select VIDEOMODE_HELPERS
> +
> +static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D',
> 'B', 'I',
> + 0, 0, 0, 0, 0, 0, 0 };
> +
> +/*
> + * The optional display controller configuration is stored in a firmware
> file.
> + * The Device Tree 'compatible' property value with a '.bin' suffix is passed
> + * to request_firmware() to fetch this file.
> + */
> +struct panel_mipi_dbi_config {
> + /* Magic string: panel_mipi_dbi_magic */
> + u8 magic[15];
> +
> + /* Config file format version */
> + u8 file_format_version;
> +
> + /*
> + * MIPI commands to execute when the display pipeline is enabled.
> + * This is used to configure the display controller.
> + *
> + * The commands are stored in a byte array with the format:
> + * command, num_parameters, [ parameter, ...], command, ...
> + *
> + * Some commands require a pause before the next command can be
> received.
> + * Inserting a delay in the command sequence is done by using the NOP
> command with one
> + * parameter: delay in miliseconds (the No Operation command is part of
> the MIPI Display
> + * Command Set where it has no parameters).
> + *
> + * Example:
> + * command 0x11
> + * sleep 120ms
> + * command 0xb1 parameters 0x01, 0x2c, 0x2d
> + * command 0x29
> + *
> + * Byte sequence:
> + * 0x11 0x00
> + * 0x00 0x01 0x78
> + * 0xb1 0x03 0x01 0x2c 0x2d
> + * 0x29 0x00
> + */
> + u8 commands[];
> +};
> +
> +struct panel_mipi_dbi_commands {
> + const u8 *buf;
> + size_t len;
> +};
> +
> +static struct panel_mipi_dbi_commands *
> +panel_mipi_dbi_check_commands(struct device *dev, const struct firmware *fw)
> +{
> + const struct panel_mipi_dbi_config *config = (struct
> panel_mipi_dbi_config *)fw->data;
> + struct panel_mipi_dbi_commands *commands;
> + size_t size = fw->size, commands_len;
> + unsigned int i = 0;
> +
> + if (size < sizeof(*config) + 2) { /* At least 1 command */
> + dev_err(dev, "config: file size=%zu is too small\n", size);
> + return ERR_PTR(-EINVAL);
> + }
> +
> + if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic)))
> {
> + dev_err(dev, "config: Bad magic: %15ph\n", config->magic);
> + return ERR_PTR(-EINVAL);
> + }
> +
> + if (config->file_format_version != 1) {
> + dev_err(dev, "config: version=%u is not supported\n",
> config->file_format_version);
> + return ERR_PTR(-EINVAL);
> + }
> +
> + drm_dev_dbg(dev, DRM_UT_DRIVER, "size=%zu version=%u\n", size,
> config->file_format_version);
> +
> + commands_len = size - sizeof(*config);
> +
> + while ((i + 1) < commands_len) {
> + u8 command = config->commands[i++];
> + u8 num_parameters = config->commands[i++];
> + const u8 *parameters = &config->commands[i];
> +
> + i += num_parameters;
> + if (i > commands_len) {
> + dev_err(dev, "config: command=0x%02x num_parameters=%u
> overflows\n",
> + command, num_parameters);
> + return ERR_PTR(-EINVAL);
> + }
> +
> + if (command == 0x00 && num_parameters == 1)
> + drm_dev_dbg(dev, DRM_UT_DRIVER, "sleep %ums\n",
> parameters[0]);
> + else
> + drm_dev_dbg(dev, DRM_UT_DRIVER, "command %02x %*ph\n",
> + command, num_parameters, parameters);
> + }
> +
> + if (i != commands_len) {
> + dev_err(dev, "config: malformed command array\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + commands = devm_kzalloc(dev, sizeof(*commands), GFP_KERNEL);
> + if (!commands)
> + return ERR_PTR(-ENOMEM);
> +
> + commands->len = commands_len;
> + commands->buf = devm_kmemdup(dev, config->commands, commands->len,
> GFP_KERNEL);
> + if (!commands->buf)
> + return ERR_PTR(-ENOMEM);
> +
> + return commands;
> +}
> +
> +static struct panel_mipi_dbi_commands
> *panel_mipi_dbi_commands_from_fw(struct device *dev)
> +{
> + struct panel_mipi_dbi_commands *commands;
> + const struct firmware *fw;
> + const char *compatible;
> + struct property *prop;
> + char fw_name[40];
> + int ret;
> +
> + of_property_for_each_string(dev->of_node, "compatible", prop,
> compatible) {
> + snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible);
> + ret = firmware_request_nowarn(&fw, fw_name, dev);
> + if (ret) {
> + drm_dev_dbg(dev, DRM_UT_DRIVER,
> + "No config file found for compatible: '%s'
> (error=%d)\n",
> + compatible, ret);
It would be more helpful to spell out that we failed to find a file
named compatible.bin here as the user may not be aware that the .bin
file is needed.
> + continue;
> + }
> +
> + commands = panel_mipi_dbi_check_commands(dev, fw);
> + release_firmware(fw);
> + return commands;
> + }
> +
> + return NULL;
> +}
> +
> +static void panel_mipi_dbi_commands_execute(struct mipi_dbi *dbi,
> + struct panel_mipi_dbi_commands
> *commands)
> +{
> + unsigned int i = 0;
> +
> + if (!commands)
> + return;
> +
> + while (i < commands->len) {
> + u8 command = commands->buf[i++];
> + u8 num_parameters = commands->buf[i++];
> + const u8 *parameters = &commands->buf[i];
> +
> + if (command == 0x00 && num_parameters == 1)
> + msleep(parameters[0]);
> + else if (num_parameters)
> + mipi_dbi_command_stackbuf(dbi, command, parameters,
> num_parameters);
> + else
> + mipi_dbi_command(dbi, command);
> +
> + i += num_parameters;
> + }
> +}
> +
> +static void panel_mipi_dbi_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 mipi_dbi *dbi = &dbidev->dbi;
> + int ret, idx;
> +
> + if (!drm_dev_enter(pipe->crtc.dev, &idx))
> + return;
> +
> + drm_dbg(pipe->crtc.dev, "\n");
> +
> + ret = mipi_dbi_poweron_conditional_reset(dbidev);
> + if (ret < 0)
> + goto out_exit;
> + if (!ret)
> + panel_mipi_dbi_commands_execute(dbi, dbidev->driver_private);
> +
> + mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
> +out_exit:
> + drm_dev_exit(idx);
> +}
> +
> +static const struct drm_simple_display_pipe_funcs panel_mipi_dbi_pipe_funcs
> = {
> + .enable = panel_mipi_dbi_enable,
> + .disable = mipi_dbi_pipe_disable,
> + .update = mipi_dbi_pipe_update,
> +};
> +
> +DEFINE_DRM_GEM_CMA_FOPS(panel_mipi_dbi_fops);
> +
> +static const struct drm_driver panel_mipi_dbi_driver = {
> + .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
> + .fops = &panel_mipi_dbi_fops,
> + DRM_GEM_CMA_DRIVER_OPS_VMAP,
> + .debugfs_init = mipi_dbi_debugfs_init,
> + .name = "panel-mipi-dbi",
> + .desc = "MIPI DBI compatible display panel",
> + .date = "20220103",
> + .major = 1,
> + .minor = 0,
> +};
> +
> +static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev *dbidev, struct
> drm_display_mode *mode)
> +{
> + struct device *dev = dbidev->drm.dev;
> + u32 width_mm = 0, height_mm = 0;
> + struct display_timing timing;
> + struct videomode vm;
> + int ret;
> +
> + ret = of_get_display_timing(dev->of_node, "panel-timing", &timing);
> + if (ret) {
> + dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n",
> dev->of_node, ret);
> + return ret;
> + }
> +
> + videomode_from_timing(&timing, &vm);
> +
> + if (!vm.hactive || vm.hfront_porch || vm.hsync_len ||
> + (vm.hback_porch + vm.hactive) > 0xffff ||
> + !vm.vactive || vm.vfront_porch || vm.vsync_len ||
> + (vm.vback_porch + vm.vactive) > 0xffff ||
> + vm.flags) {
> + dev_err(dev, "%pOF: panel-timing out of bounds\n",
> dev->of_node);
> + return -EINVAL;
> + }
We should have a helper that implements this. Maybe the display_timing
=> display_mode helper could do it.
> +
> + /* The driver doesn't use the pixel clock but it is mandatory so fake
> one if not set */
> + if (!vm.pixelclock)
> + vm.pixelclock = (vm.hback_porch + vm.hactive) * (vm.vback_porch
> + vm.vactive) * 60;
> +
> + dbidev->top_offset = vm.vback_porch;
> + dbidev->left_offset = vm.hback_porch;
> +
> + memset(mode, 0, sizeof(*mode));
> + drm_display_mode_from_videomode(&vm, mode);
> + mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
> +
> + ret = device_property_read_u32(dev, "width-mm", &width_mm);
> + if (ret && ret != -EINVAL)
> + return ret;
> +
> + ret = device_property_read_u32(dev, "height-mm", &height_mm);
> + if (ret && ret != -EINVAL)
> + return ret;
> +
> + mode->width_mm = width_mm;
> + mode->height_mm = height_mm;
> +
> + drm_mode_debug_printmodeline(mode);
> +
> + return 0;
> +}
> +
> +static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
> +{
> + struct device *dev = &spi->dev;
> + struct drm_display_mode mode;
> + struct mipi_dbi_dev *dbidev;
> + struct drm_device *drm;
> + struct mipi_dbi *dbi;
> + struct gpio_desc *dc;
> + int ret;
> +
> + dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct
> mipi_dbi_dev, drm);
> + if (IS_ERR(dbidev))
> + return PTR_ERR(dbidev);
> +
> + dbi = &dbidev->dbi;
> + drm = &dbidev->drm;
> +
> + ret = panel_mipi_dbi_get_mode(dbidev, &mode);
> + if (ret)
> + return ret;
> +
> + dbidev->regulator = devm_regulator_get(dev, "power");
> + if (IS_ERR(dbidev->regulator))
> + return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
> + "Failed to get regulator 'power'\n");
> +
> + dbidev->backlight = devm_of_find_backlight(dev);
> + if (IS_ERR(dbidev->backlight))
> + return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed
> to get backlight\n");
> +
> + dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
> + if (IS_ERR(dbi->reset))
> + return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get
> GPIO 'reset'\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 GPIO
> 'dc'\n");
> +
> + ret = mipi_dbi_spi_init(spi, dbi, dc);
> + if (ret)
> + return ret;
> +
> + if (device_property_present(dev, "write-only"))
> + dbi->read_commands = NULL;
read_commands are unused - so the write-only property is in practice
ignored.
> +
> + dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
> + if (IS_ERR(dbidev->driver_private))
> + return PTR_ERR(dbidev->driver_private);
> +
> + ret = mipi_dbi_dev_init(dbidev, &panel_mipi_dbi_pipe_funcs, &mode, 0);
> + if (ret)
> + return ret;
> +
> + drm_mode_config_reset(drm);
> +
> + ret = drm_dev_register(drm, 0);
> + if (ret)
> + return ret;
> +
> + spi_set_drvdata(spi, drm);
> +
> + drm_fbdev_generic_setup(drm, 0);
> +
> + return 0;
> +}
> +
> +static int panel_mipi_dbi_spi_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 panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
> +{
> + drm_atomic_helper_shutdown(spi_get_drvdata(spi));
> +}
> +
> +static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev)
> +{
> + return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
> +}
> +
> +static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev)
> +{
> + drm_mode_config_helper_resume(dev_get_drvdata(dev));
> +
> + return 0;
> +}
> +
> +static const struct dev_pm_ops panel_mipi_dbi_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend,
> panel_mipi_dbi_pm_resume)
> +};
> +
> +static const struct of_device_id panel_mipi_dbi_spi_of_match[] = {
> + { .compatible = "panel-mipi-dbi-spi" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match);
> +
> +static const struct spi_device_id panel_mipi_dbi_spi_id[] = {
> + { "panel-mipi-dbi-spi", 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id);
> +
> +static struct spi_driver panel_mipi_dbi_spi_driver = {
> + .driver = {
> + .name = "panel-mipi-dbi-spi",
> + .owner = THIS_MODULE,
> + .of_match_table = panel_mipi_dbi_spi_of_match,
> + .pm = &panel_mipi_dbi_pm_ops,
> + },
> + .id_table = panel_mipi_dbi_spi_id,
> + .probe = panel_mipi_dbi_spi_probe,
> + .remove = panel_mipi_dbi_spi_remove,
> + .shutdown = panel_mipi_dbi_spi_shutdown,
> +};
> +module_spi_driver(panel_mipi_dbi_spi_driver);
> +
> +MODULE_DESCRIPTION("MIPI DBI compatible display panel driver");
> +MODULE_AUTHOR("Noralf Trønnes");
> +MODULE_LICENSE("GPL");
> --
> 2.33.0
