// 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_fbdev_dma.h>
#include <drm/drm_gem_atomic_helper.h>
#include <drm/drm_gem_dma_helper.h>
#include <drm/drm_managed.h>
#include <drm/drm_mipi_dbi.h>
#include <drm/drm_modes.h>
#include <drm/drm_modeset_helper.h>
#include <video/mipi_display.h>
struct panel_mipi_dbi_format {
const char *name;
u32 fourcc;
unsigned int bpp;
};
static const struct panel_mipi_dbi_format panel_mipi_dbi_formats[] = {
{ "r5g6b5", DRM_FORMAT_RGB565, 16 },
{ "b6x2g6x2r6x2", DRM_FORMAT_RGB888, 24 },
};
static int panel_mipi_dbi_get_format(struct device *dev, u32 *formats, unsigned int *bpp)
{
const char *format_name;
unsigned int i;
int ret;
formats[1] = DRM_FORMAT_XRGB8888;
ret = device_property_read_string(dev, "format", &format_name);
if (ret) {
/* Old Device Trees don't have this property */
formats[0] = DRM_FORMAT_RGB565;
*bpp = 16;
return 0;
}
for (i = 0; i < ARRAY_SIZE(panel_mipi_dbi_formats); i++) {
const struct panel_mipi_dbi_format *format = &panel_mipi_dbi_formats[i];
if (strcmp(format_name, format->name))
continue;
formats[0] = format->fourcc;
*bpp = format->bpp;
return 0;
}
dev_err(dev, "Pixel format is not supported: '%s'\n", format_name);
return -EINVAL;
}
static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D', 'B', 'I',
0, 0, 0, 0, 0, 0, 0 };
/*
* The 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;
char fw_name[40];
int ret;
ret = of_property_read_string_index(dev->of_node, "compatible", 0, &compatible);
if (ret)
return ERR_PTR(ret);
snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible);
ret = request_firmware(&fw, fw_name, dev);
if (ret) {
dev_err(dev, "No config file found for compatible '%s' (error=%d)\n",
compatible, ret);
return ERR_PTR(ret);
}
commands = panel_mipi_dbi_check_commands(dev, fw);
release_firmware(fw);
return commands;
}
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 = {
DRM_MIPI_DBI_SIMPLE_DISPLAY_PIPE_FUNCS(panel_mipi_dbi_enable),
};
DEFINE_DRM_GEM_DMA_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_DMA_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;
u16 hback_porch, vback_porch;
int ret;
ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL);
if (ret) {
dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret);
return ret;
}
mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
hback_porch = mode->htotal - mode->hsync_end;
vback_porch = mode->vtotal - mode->vsync_end;
/*
* Make sure width and height are set and that only back porch and
* pixelclock are set in the other timing values. Also check that
* width and height don't exceed the 16-bit value specified by MIPI DCS.
*/
if (!mode->hdisplay || !mode->vdisplay || mode->flags ||
mode->hsync_end > mode->hdisplay || (hback_porch + mode->hdisplay) > 0xffff ||
mode->vsync_end > mode->vdisplay || (vback_porch + mode->vdisplay) > 0xffff) {
dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node);
return -EINVAL;
}
/* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */
if (!mode->clock)
mode->clock = mode->htotal * mode->vtotal * 60 / 1000;
dbidev->top_offset = vback_porch;
dbidev->left_offset = hback_porch;
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;
unsigned int bpp;
size_t buf_size;
u32 formats[2];
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->io_regulator = devm_regulator_get(dev, "io");
if (IS_ERR(dbidev->io_regulator))
return dev_err_probe(dev, PTR_ERR(dbidev->io_regulator),
"Failed to get regulator 'io'\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");
/* Multiple panels can share the "dc" GPIO, but only if they are on the same SPI bus! */
dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE);
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;
dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
if (IS_ERR(dbidev->driver_private))
return PTR_ERR(dbidev->driver_private);
ret = panel_mipi_dbi_get_format(dev, formats, &bpp);
if (ret)
return ret;
buf_size = DIV_ROUND_UP(mode.hdisplay * mode.vdisplay * bpp, 8);
ret = mipi_dbi_dev_init_with_formats(dbidev, &panel_mipi_dbi_pipe_funcs,
formats, ARRAY_SIZE(formats),
&mode, 0, buf_size);
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_dma_setup(drm, 0);
return 0;
}
static void 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);
}
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",
.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");
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