// SPDX-License-Identifier: GPL-2.0-or-later
/*
* MIPI Display Bus Interface (DBI) LCD controller support
*
* Copyright 2016 Noralf Trønnes
*/
#include <linux/backlight.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <drm/drm_connector.h>
#include <drm/drm_damage_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_file.h>
#include <drm/drm_format_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_gem.h>
#include <drm/drm_gem_atomic_helper.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_mipi_dbi.h>
#include <drm/drm_modes.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_rect.h>
#include <video/mipi_display.h>
#define MIPI_DBI_MAX_SPI_READ_SPEED 2000000 /* 2MHz */
#define DCS_POWER_MODE_DISPLAY BIT(2)
#define DCS_POWER_MODE_DISPLAY_NORMAL_MODE BIT(3)
#define DCS_POWER_MODE_SLEEP_MODE BIT(4)
#define DCS_POWER_MODE_PARTIAL_MODE BIT(5)
#define DCS_POWER_MODE_IDLE_MODE BIT(6)
#define DCS_POWER_MODE_RESERVED_MASK (BIT(0) | BIT(1) | BIT(7))
/**
* DOC: overview
*
* This library provides helpers for MIPI Display Bus Interface (DBI)
* compatible display controllers.
*
* Many controllers for tiny lcd displays are MIPI compliant and can use this
* library. If a controller uses registers 0x2A and 0x2B to set the area to
* update and uses register 0x2C to write to frame memory, it is most likely
* MIPI compliant.
*
* Only MIPI Type 1 displays are supported since a full frame memory is needed.
*
* There are 3 MIPI DBI implementation types:
*
* A. Motorola 6800 type parallel bus
*
* B. Intel 8080 type parallel bus
*
* C. SPI type with 3 options:
*
* 1. 9-bit with the Data/Command signal as the ninth bit
* 2. Same as above except it's sent as 16 bits
* 3. 8-bit with the Data/Command signal as a separate D/CX pin
*
* Currently mipi_dbi only supports Type C options 1 and 3 with
* mipi_dbi_spi_init().
*/
#define MIPI_DBI_DEBUG_COMMAND(cmd, data, len) \
({ \
if (!len) \
DRM_DEBUG_DRIVER("cmd=%02x\n", cmd); \
else if (len <= 32) \
DRM_DEBUG_DRIVER("cmd=%02x, par=%*ph\n", cmd, (int)len, data);\
else \
DRM_DEBUG_DRIVER("cmd=%02x, len=%zu\n", cmd, len); \
})
static const u8 mipi_dbi_dcs_read_commands[] = {
MIPI_DCS_GET_DISPLAY_ID,
MIPI_DCS_GET_RED_CHANNEL,
MIPI_DCS_GET_GREEN_CHANNEL,
MIPI_DCS_GET_BLUE_CHANNEL,
MIPI_DCS_GET_DISPLAY_STATUS,
MIPI_DCS_GET_POWER_MODE,
MIPI_DCS_GET_ADDRESS_MODE,
MIPI_DCS_GET_PIXEL_FORMAT,
MIPI_DCS_GET_DISPLAY_MODE,
MIPI_DCS_GET_SIGNAL_MODE,
MIPI_DCS_GET_DIAGNOSTIC_RESULT,
MIPI_DCS_READ_MEMORY_START,
MIPI_DCS_READ_MEMORY_CONTINUE,
MIPI_DCS_GET_SCANLINE,
MIPI_DCS_GET_DISPLAY_BRIGHTNESS,
MIPI_DCS_GET_CONTROL_DISPLAY,
MIPI_DCS_GET_POWER_SAVE,
MIPI_DCS_GET_CABC_MIN_BRIGHTNESS,
MIPI_DCS_READ_DDB_START,
MIPI_DCS_READ_DDB_CONTINUE,
0, /* sentinel */
};
static bool mipi_dbi_command_is_read(struct mipi_dbi *dbi, u8 cmd)
{
unsigned int i;
if (!dbi->read_commands)
return false;
for (i = 0; i < 0xff; i++) {
if (!dbi->read_commands[i])
return false;
if (cmd == dbi->read_commands[i])
return true;
}
return false;
}
/**
* mipi_dbi_command_read - MIPI DCS read command
* @dbi: MIPI DBI structure
* @cmd: Command
* @val: Value read
*
* Send MIPI DCS read command to the controller.
*
* Returns:
* Zero on success, negative error code on failure.
*/
int mipi_dbi_command_read(struct mipi_dbi *dbi, u8 cmd, u8 *val)
{
if (!dbi->read_commands)
return -EACCES;
if (!mipi_dbi_command_is_read(dbi, cmd))
return -EINVAL;
return mipi_dbi_command_buf(dbi, cmd, val, 1);
}
EXPORT_SYMBOL(mipi_dbi_command_read);
/**
* mipi_dbi_command_buf - MIPI DCS command with parameter(s) in an array
* @dbi: MIPI DBI structure
* @cmd: Command
* @data: Parameter buffer
* @len: Buffer length
*
* Returns:
* Zero on success, negative error code on failure.
*/
int mipi_dbi_command_buf(struct mipi_dbi *dbi, u8 cmd, u8 *data, size_t len)
{
u8 *cmdbuf;
int ret;
/* SPI requires dma-safe buffers */
cmdbuf = kmemdup(&cmd, 1, GFP_KERNEL);
if (!cmdbuf)
return -ENOMEM;
mutex_lock(&dbi->cmdlock);
ret = dbi->command(dbi, cmdbuf, data, len);
mutex_unlock(&dbi->cmdlock);
kfree(cmdbuf);
return ret;
}
EXPORT_SYMBOL(mipi_dbi_command_buf);
/* This should only be used by mipi_dbi_command() */
int mipi_dbi_command_stackbuf(struct mipi_dbi *dbi, u8 cmd, const u8 *data,
size_t len)
{
u8 *buf;
int ret;
buf = kmemdup(data, len, GFP_KERNEL);
if (!buf)
return -ENOMEM;
ret = mipi_dbi_command_buf(dbi, cmd, buf, len);
kfree(buf);
return ret;
}
EXPORT_SYMBOL(mipi_dbi_command_stackbuf);
/**
* mipi_dbi_buf_copy - Copy a framebuffer, transforming it if necessary
* @dst: The destination buffer
* @src: The source buffer
* @fb: The source framebuffer
* @clip: Clipping rectangle of the area to be copied
* @swap: When true, swap MSB/LSB of 16-bit values
* @fmtcnv_state: Format-conversion state
*
* Returns:
* Zero on success, negative error code on failure.
*/
int mipi_dbi_buf_copy(void *dst, struct iosys_map *src, struct drm_framebuffer *fb,
struct drm_rect *clip, bool swap,
struct drm_format_conv_state *fmtcnv_state)
{
struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
struct drm_gem_object *gem = drm_gem_fb_get_obj(fb, 0);
struct iosys_map dst_map = IOSYS_MAP_INIT_VADDR(dst);
int ret;
ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
if (ret)
return ret;
switch (fb->format->format) {
case DRM_FORMAT_RGB565:
if (swap)
drm_fb_swab(&dst_map, NULL, src, fb, clip, !gem->import_attach,
fmtcnv_state);
else
drm_fb_memcpy(&dst_map, NULL, src, fb, clip);
break;
case DRM_FORMAT_RGB888:
drm_fb_memcpy(&dst_map, NULL, src, fb, clip);
break;
case DRM_FORMAT_XRGB8888:
switch (dbidev->pixel_format) {
case DRM_FORMAT_RGB565:
drm_fb_xrgb8888_to_rgb565(&dst_map, NULL, src, fb, clip, fmtcnv_state, swap);
break;
case DRM_FORMAT_RGB888:
drm_fb_xrgb8888_to_rgb888(&dst_map, NULL, src, fb, clip, fmtcnv_state);
break;
}
break;
default:
drm_err_once(fb->dev, "Format is not supported: %p4cc\n",
&fb->format->format);
ret = -EINVAL;
}
drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
return ret;
}
EXPORT_SYMBOL(mipi_dbi_buf_copy);
static void mipi_dbi_set_window_address(struct mipi_dbi_dev *dbidev,
unsigned int xs, unsigned int xe,
unsigned int ys, unsigned int ye)
{
struct mipi_dbi *dbi = &dbidev->dbi;
xs += dbidev->left_offset;
xe += dbidev->left_offset;
ys += dbidev->top_offset;
ye += dbidev->top_offset;
mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS, (xs >> 8) & 0xff,
xs & 0xff, (xe >> 8) & 0xff, xe & 0xff);
mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS, (ys >> 8) & 0xff,
ys & 0xff, (ye >> 8) & 0xff, ye & 0xff);
}
static void mipi_dbi_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
struct drm_rect *rect, struct drm_format_conv_state *fmtcnv_state)
{
struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
unsigned int height = rect->y2 - rect->y1;
unsigned int width = rect->x2 - rect->x1;
const struct drm_format_info *dst_format;
struct mipi_dbi *dbi = &dbidev->dbi;
bool swap = dbi->swap_bytes;
int ret = 0;
size_t len;
bool full;
void *tr;
full = width == fb->width && height == fb->height;
DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
if (!dbi->dc || !full || swap ||
fb->format->format == DRM_FORMAT_XRGB8888) {
tr = dbidev->tx_buf;
ret = mipi_dbi_buf_copy(tr, src, fb, rect, swap, fmtcnv_state);
if (ret)
goto err_msg;
} else {
tr = src->vaddr; /* TODO: Use mapping abstraction properly */
}
mipi_dbi_set_window_address(dbidev, rect->x1, rect->x2 - 1, rect->y1,
rect->y2 - 1);
if (fb->format->format == DRM_FORMAT_XRGB8888)
dst_format = drm_format_info(dbidev->pixel_format);
else
dst_format = fb->format;
len = drm_format_info_min_pitch(dst_format, 0, width) * height;
ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START, tr, len);
err_msg:
if (ret)
drm_err_once(fb->dev, "Failed to update display %d\n", ret);
}
/**
* mipi_dbi_pipe_mode_valid - MIPI DBI mode-valid helper
* @pipe: Simple display pipe
* @mode: The mode to test
*
* This function validates a given display mode against the MIPI DBI's hardware
* display. Drivers can use this as their &drm_simple_display_pipe_funcs->mode_valid
* callback.
*/
enum drm_mode_status mipi_dbi_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
const struct drm_display_mode *mode)
{
struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
return drm_crtc_helper_mode_valid_fixed(&pipe->crtc, mode, &dbidev->mode);
}
EXPORT_SYMBOL(mipi_dbi_pipe_mode_valid);
/**
* mipi_dbi_pipe_update - Display pipe update helper
* @pipe: Simple display pipe
* @old_state: Old plane state
*
* This function handles framebuffer flushing and vblank events. Drivers can use
* this as their &drm_simple_display_pipe_funcs->update callback.
*/
void mipi_dbi_pipe_update(struct drm_simple_display_pipe *pipe,
struct drm_plane_state *old_state)
{
struct drm_plane_state *state = pipe->plane.state;
struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
struct drm_framebuffer *fb = state->fb;
struct drm_rect rect;
int idx;
if (!pipe->crtc.state->active)
return;
if (WARN_ON(!fb))
return;
if (!drm_dev_enter(fb->dev, &idx))
return;
if (drm_atomic_helper_damage_merged(old_state, state, &rect))
mipi_dbi_fb_dirty(&shadow_plane_state->data[0], fb, &rect,
&shadow_plane_state->fmtcnv_state);
drm_dev_exit(idx);
}
EXPORT_SYMBOL(mipi_dbi_pipe_update);
/**
* mipi_dbi_enable_flush - MIPI DBI enable helper
* @dbidev: MIPI DBI device structure
* @crtc_state: CRTC state
* @plane_state: Plane state
*
* Flushes the whole framebuffer and enables the backlight. Drivers can use this
* in their &drm_simple_display_pipe_funcs->enable callback.
*
* Note: Drivers which don't use mipi_dbi_pipe_update() because they have custom
* framebuffer flushing, can't use this function since they both use the same
* flushing code.
*/
void mipi_dbi_enable_flush(struct mipi_dbi_dev *dbidev,
struct drm_crtc_state *crtc_state,
struct drm_plane_state *plane_state)
{
struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
struct drm_framebuffer *fb = plane_state->fb;
struct drm_rect rect = {
.x1 = 0,
.x2 = fb->width,
.y1 = 0,
.y2 = fb->height,
};
int idx;
if (!drm_dev_enter(&dbidev->drm, &idx))
return;
mipi_dbi_fb_dirty(&shadow_plane_state->data[0], fb, &rect,
&shadow_plane_state->fmtcnv_state);
backlight_enable(dbidev->backlight);
drm_dev_exit(idx);
}
EXPORT_SYMBOL(mipi_dbi_enable_flush);
static void mipi_dbi_blank(struct mipi_dbi_dev *dbidev)
{
struct drm_device *drm = &dbidev->drm;
u16 height = drm->mode_config.min_height;
u16 width = drm->mode_config.min_width;
struct mipi_dbi *dbi = &dbidev->dbi;
size_t len = width * height * 2;
int idx;
if (!drm_dev_enter(drm, &idx))
return;
memset(dbidev->tx_buf, 0, len);
mipi_dbi_set_window_address(dbidev, 0, width - 1, 0, height - 1);
mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
(u8 *)dbidev->tx_buf, len);
drm_dev_exit(idx);
}
/**
* mipi_dbi_pipe_disable - MIPI DBI pipe disable helper
* @pipe: Display pipe
*
* This function disables backlight if present, if not the display memory is
* blanked. The regulator is disabled if in use. Drivers can use this as their
* &drm_simple_display_pipe_funcs->disable callback.
*/
void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe)
{
struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
DRM_DEBUG_KMS("\n");
if (dbidev->backlight)
backlight_disable(dbidev->backlight);
else
mipi_dbi_blank(dbidev);
if (dbidev->regulator)
regulator_disable(dbidev->regulator);
if (dbidev->io_regulator)
regulator_disable(dbidev->io_regulator);
}
EXPORT_SYMBOL(mipi_dbi_pipe_disable);
/**
* mipi_dbi_pipe_begin_fb_access - MIPI DBI pipe begin-access helper
* @pipe: Display pipe
* @plane_state: Plane state
*
* This function implements struct &drm_simple_display_funcs.begin_fb_access.
*
* See drm_gem_begin_shadow_fb_access() for details and mipi_dbi_pipe_cleanup_fb()
* for cleanup.
*
* Returns:
* 0 on success, or a negative errno code otherwise.
*/
int mipi_dbi_pipe_begin_fb_access(struct drm_simple_display_pipe *pipe,
struct drm_plane_state *plane_state)
{
return drm_gem_begin_shadow_fb_access(&pipe->plane, plane_state);
}
EXPORT_SYMBOL(mipi_dbi_pipe_begin_fb_access);
/**
* mipi_dbi_pipe_end_fb_access - MIPI DBI pipe end-access helper
* @pipe: Display pipe
* @plane_state: Plane state
*
* This function implements struct &drm_simple_display_funcs.end_fb_access.
*
* See mipi_dbi_pipe_begin_fb_access().
*/
void mipi_dbi_pipe_end_fb_access(struct drm_simple_display_pipe *pipe,
struct drm_plane_state *plane_state)
{
drm_gem_end_shadow_fb_access(&pipe->plane, plane_state);
}
EXPORT_SYMBOL(mipi_dbi_pipe_end_fb_access);
/**
* mipi_dbi_pipe_reset_plane - MIPI DBI plane-reset helper
* @pipe: Display pipe
*
* This function implements struct &drm_simple_display_funcs.reset_plane
* for MIPI DBI planes.
*/
void mipi_dbi_pipe_reset_plane(struct drm_simple_display_pipe *pipe)
{
drm_gem_reset_shadow_plane(&pipe->plane);
}
EXPORT_SYMBOL(mipi_dbi_pipe_reset_plane);
/**
* mipi_dbi_pipe_duplicate_plane_state - duplicates MIPI DBI plane state
* @pipe: Display pipe
*
* This function implements struct &drm_simple_display_funcs.duplicate_plane_state
* for MIPI DBI planes.
*
* See drm_gem_duplicate_shadow_plane_state() for additional details.
*
* Returns:
* A pointer to a new plane state on success, or NULL otherwise.
*/
struct drm_plane_state *mipi_dbi_pipe_duplicate_plane_state(struct drm_simple_display_pipe *pipe)
{
return drm_gem_duplicate_shadow_plane_state(&pipe->plane);
}
EXPORT_SYMBOL(mipi_dbi_pipe_duplicate_plane_state);
/**
* mipi_dbi_pipe_destroy_plane_state - cleans up MIPI DBI plane state
* @pipe: Display pipe
* @plane_state: Plane state
*
* This function implements struct drm_simple_display_funcs.destroy_plane_state
* for MIPI DBI planes.
*
* See drm_gem_destroy_shadow_plane_state() for additional details.
*/
void mipi_dbi_pipe_destroy_plane_state(struct drm_simple_display_pipe *pipe,
struct drm_plane_state *plane_state)
{
drm_gem_destroy_shadow_plane_state(&pipe->plane, plane_state);
}
EXPORT_SYMBOL(mipi_dbi_pipe_destroy_plane_state);
static int mipi_dbi_connector_get_modes(struct drm_connector *connector)
{
struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(connector->dev);
return drm_connector_helper_get_modes_fixed(connector, &dbidev->mode);
}
static const struct drm_connector_helper_funcs mipi_dbi_connector_hfuncs = {
.get_modes = mipi_dbi_connector_get_modes,
};
static const struct drm_connector_funcs mipi_dbi_connector_funcs = {
.reset = drm_atomic_helper_connector_reset,
.fill_modes = drm_helper_probe_single_connector_modes,
.destroy = drm_connector_cleanup,
.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
};
static int mipi_dbi_rotate_mode(struct drm_display_mode *mode,
unsigned int rotation)
{
if (rotation == 0 || rotation == 180) {
return 0;
} else if (rotation == 90 || rotation == 270) {
swap(mode->hdisplay, mode->vdisplay);
swap(mode->hsync_start, mode->vsync_start);
swap(mode->hsync_end, mode->vsync_end);
swap(mode->htotal, mode->vtotal);
swap(mode->width_mm, mode->height_mm);
return 0;
} else {
return -EINVAL;
}
}
static const struct drm_mode_config_funcs mipi_dbi_mode_config_funcs = {
.fb_create = drm_gem_fb_create_with_dirty,
.atomic_check = drm_atomic_helper_check,
.atomic_commit = drm_atomic_helper_commit,
};
static const uint32_t mipi_dbi_formats[] = {
DRM_FORMAT_RGB565,
DRM_FORMAT_XRGB8888,
};
/**
* mipi_dbi_dev_init_with_formats - MIPI DBI device initialization with custom formats
* @dbidev: MIPI DBI device structure to initialize
* @funcs: Display pipe functions
* @formats: Array of supported formats (DRM_FORMAT\_\*).
* @format_count: Number of elements in @formats
* @mode: Display mode
* @rotation: Initial rotation in degrees Counter Clock Wise
* @tx_buf_size: Allocate a transmit buffer of this size.
*
* This function sets up a &drm_simple_display_pipe with a &drm_connector that
* has one fixed &drm_display_mode which is rotated according to @rotation.
* This mode is used to set the mode config min/max width/height properties.
*
* Use mipi_dbi_dev_init() if you want native RGB565 and emulated XRGB8888 format.
*
* Note:
* Some of the helper functions expects RGB565 to be the default format and the
* transmit buffer sized to fit that.
*
* Returns:
* Zero on success, negative error code on failure.
*/
int mipi_dbi_dev_init_with_formats(struct mipi_dbi_dev *dbidev,
const struct drm_simple_display_pipe_funcs *funcs,
const uint32_t *formats, unsigned int format_count,
const struct drm_display_mode *mode,
unsigned int rotation, size_t tx_buf_size)
{
static const uint64_t modifiers[] = {
DRM_FORMAT_MOD_LINEAR,
DRM_FORMAT_MOD_INVALID
};
struct drm_device *drm = &dbidev->drm;
int ret;
if (!dbidev->dbi.command)
return -EINVAL;
ret = drmm_mode_config_init(drm);
if (ret)
return ret;
dbidev->tx_buf = devm_kmalloc(drm->dev, tx_buf_size, GFP_KERNEL);
if (!dbidev->tx_buf)
return -ENOMEM;
drm_mode_copy(&dbidev->mode, mode);
ret = mipi_dbi_rotate_mode(&dbidev->mode, rotation);
if (ret) {
DRM_ERROR("Illegal rotation value %u\n", rotation);
return -EINVAL;
}
drm_connector_helper_add(&dbidev->connector, &mipi_dbi_connector_hfuncs);
ret = drm_connector_init(drm, &dbidev->connector, &mipi_dbi_connector_funcs,
DRM_MODE_CONNECTOR_SPI);
if (ret)
return ret;
ret = drm_simple_display_pipe_init(drm, &dbidev->pipe, funcs, formats, format_count,
modifiers, &dbidev->connector);
if (ret)
return ret;
drm_plane_enable_fb_damage_clips(&dbidev->pipe.plane);
drm->mode_config.funcs = &mipi_dbi_mode_config_funcs;
drm->mode_config.min_width = dbidev->mode.hdisplay;
drm->mode_config.max_width = dbidev->mode.hdisplay;
drm->mode_config.min_height = dbidev->mode.vdisplay;
drm->mode_config.max_height = dbidev->mode.vdisplay;
dbidev->rotation = rotation;
dbidev->pixel_format = formats[0];
if (formats[0] == DRM_FORMAT_RGB888)
dbidev->dbi.write_memory_bpw = 8;
DRM_DEBUG_KMS("rotation = %u\n", rotation);
return 0;
}
EXPORT_SYMBOL(mipi_dbi_dev_init_with_formats);
/**
* mipi_dbi_dev_init - MIPI DBI device initialization
* @dbidev: MIPI DBI device structure to initialize
* @funcs: Display pipe functions
* @mode: Display mode
* @rotation: Initial rotation in degrees Counter Clock Wise
*
* This function sets up a &drm_simple_display_pipe with a &drm_connector that
* has one fixed &drm_display_mode which is rotated according to @rotation.
* This mode is used to set the mode config min/max width/height properties.
* Additionally &mipi_dbi.tx_buf is allocated.
*
* Supported formats: Native RGB565 and emulated XRGB8888.
*
* Returns:
* Zero on success, negative error code on failure.
*/
int mipi_dbi_dev_init(struct mipi_dbi_dev *dbidev,
const struct drm_simple_display_pipe_funcs *funcs,
const struct drm_display_mode *mode, unsigned int rotation)
{
size_t bufsize = mode->vdisplay * mode->hdisplay * sizeof(u16);
dbidev->drm.mode_config.preferred_depth = 16;
return mipi_dbi_dev_init_with_formats(dbidev, funcs, mipi_dbi_formats,
ARRAY_SIZE(mipi_dbi_formats), mode,
rotation, bufsize);
}
EXPORT_SYMBOL(mipi_dbi_dev_init);
/**
* mipi_dbi_hw_reset - Hardware reset of controller
* @dbi: MIPI DBI structure
*
* Reset controller if the &mipi_dbi->reset gpio is set.
*/
void mipi_dbi_hw_reset(struct mipi_dbi *dbi)
{
if (!dbi->reset)
return;
gpiod_set_value_cansleep(dbi->reset, 0);
usleep_range(20, 1000);
gpiod_set_value_cansleep(dbi->reset, 1);
msleep(120);
}
EXPORT_SYMBOL(mipi_dbi_hw_reset);
/**
* mipi_dbi_display_is_on - Check if display is on
* @dbi: MIPI DBI structure
*
* This function checks the Power Mode register (if readable) to see if
* display output is turned on. This can be used to see if the bootloader
* has already turned on the display avoiding flicker when the pipeline is
* enabled.
*
* Returns:
* true if the display can be verified to be on, false otherwise.
*/
bool mipi_dbi_display_is_on(struct mipi_dbi *dbi)
{
u8 val;
if (mipi_dbi_command_read(dbi, MIPI_DCS_GET_POWER_MODE, &val))
return false;
val &= ~DCS_POWER_MODE_RESERVED_MASK;
/* The poweron/reset value is 08h DCS_POWER_MODE_DISPLAY_NORMAL_MODE */
if (val != (DCS_POWER_MODE_DISPLAY |
DCS_POWER_MODE_DISPLAY_NORMAL_MODE | DCS_POWER_MODE_SLEEP_MODE))
return false;
DRM_DEBUG_DRIVER("Display is ON\n");
return true;
}
EXPORT_SYMBOL(mipi_dbi_display_is_on);
static int mipi_dbi_poweron_reset_conditional(struct mipi_dbi_dev *dbidev, bool cond)
{
struct device *dev = dbidev->drm.dev;
struct mipi_dbi *dbi = &dbidev->dbi;
int ret;
if (dbidev->regulator) {
ret = regulator_enable(dbidev->regulator);
if (ret) {
DRM_DEV_ERROR(dev, "Failed to enable regulator (%d)\n", ret);
return ret;
}
}
if (dbidev->io_regulator) {
ret = regulator_enable(dbidev->io_regulator);
if (ret) {
DRM_DEV_ERROR(dev, "Failed to enable I/O regulator (%d)\n", ret);
if (dbidev->regulator)
regulator_disable(dbidev->regulator);
return ret;
}
}
if (cond && mipi_dbi_display_is_on(dbi))
return 1;
mipi_dbi_hw_reset(dbi);
ret = mipi_dbi_command(dbi, MIPI_DCS_SOFT_RESET);
if (ret) {
DRM_DEV_ERROR(dev, "Failed to send reset command (%d)\n", ret);
if (dbidev->regulator)
regulator_disable(dbidev->regulator);
if (dbidev->io_regulator)
regulator_disable(dbidev->io_regulator);
return ret;
}
/*
* If we did a hw reset, we know the controller is in Sleep mode and
* per MIPI DSC spec should wait 5ms after soft reset. If we didn't,
* we assume worst case and wait 120ms.
*/
if (dbi->reset)
usleep_range(5000, 20000);
else
msleep(120);
return 0;
}
/**
* mipi_dbi_poweron_reset - MIPI DBI poweron and reset
* @dbidev: MIPI DBI device structure
*
* This function enables the regulator if used and does a hardware and software
* reset.
*
* Returns:
* Zero on success, or a negative error code.
*/
int mipi_dbi_poweron_reset(struct mipi_dbi_dev *dbidev)
{
return mipi_dbi_poweron_reset_conditional(dbidev, false);
}
EXPORT_SYMBOL(mipi_dbi_poweron_reset);
/**
* mipi_dbi_poweron_conditional_reset - MIPI DBI poweron and conditional reset
* @dbidev: MIPI DBI device structure
*
* This function enables the regulator if used and if the display is off, it
* does a hardware and software reset. If mipi_dbi_display_is_on() determines
* that the display is on, no reset is performed.
*
* Returns:
* Zero if the controller was reset, 1 if the display was already on, or a
* negative error code.
*/
int mipi_dbi_poweron_conditional_reset(struct mipi_dbi_dev *dbidev)
{
return mipi_dbi_poweron_reset_conditional(dbidev, true);
}
EXPORT_SYMBOL(mipi_dbi_poweron_conditional_reset);
#if IS_ENABLED(CONFIG_SPI)
/**
* mipi_dbi_spi_cmd_max_speed - get the maximum SPI bus speed
* @spi: SPI device
* @len: The transfer buffer length.
*
* Many controllers have a max speed of 10MHz, but can be pushed way beyond
* that. Increase reliability by running pixel data at max speed and the rest
* at 10MHz, preventing transfer glitches from messing up the init settings.
*/
u32 mipi_dbi_spi_cmd_max_speed(struct spi_device *spi, size_t len)
{
if (len > 64)
return 0; /* use default */
return min_t(u32, 10000000, spi->max_speed_hz);
}
EXPORT_SYMBOL(mipi_dbi_spi_cmd_max_speed);
/*
* MIPI DBI Type C Option 1
*
* If the SPI controller doesn't have 9 bits per word support,
* use blocks of 9 bytes to send 8x 9-bit words using a 8-bit SPI transfer.
* Pad partial blocks with MIPI_DCS_NOP (zero).
* This is how the D/C bit (x) is added:
* x7654321
* 0x765432
* 10x76543
* 210x7654
* 3210x765
* 43210x76
* 543210x7
* 6543210x
* 76543210
*/
static int mipi_dbi_spi1e_transfer(struct mipi_dbi *dbi, int dc,
const void *buf, size_t len,
unsigned int bpw)
{
bool swap_bytes = (bpw == 16);
size_t chunk, max_chunk = dbi->tx_buf9_len;
struct spi_device *spi = dbi->spi;
struct spi_transfer tr = {
.tx_buf = dbi->tx_buf9,
.bits_per_word = 8,
};
struct spi_message m;
const u8 *src = buf;
int i, ret;
u8 *dst;
if (drm_debug_enabled(DRM_UT_DRIVER))
pr_debug("[drm:%s] dc=%d, max_chunk=%zu, transfers:\n",
__func__, dc, max_chunk);
tr.speed_hz = mipi_dbi_spi_cmd_max_speed(spi, len);
spi_message_init_with_transfers(&m, &tr, 1);
if (!dc) {
if (WARN_ON_ONCE(len != 1))
return -EINVAL;
/* Command: pad no-op's (zeroes) at beginning of block */
dst = dbi->tx_buf9;
memset(dst, 0, 9);
dst[8] = *src;
tr.len = 9;
return spi_sync(spi, &m);
}
/* max with room for adding one bit per byte */
max_chunk = max_chunk / 9 * 8;
/* but no bigger than len */
max_chunk = min(max_chunk, len);
/* 8 byte blocks */
max_chunk = max_t(size_t, 8, max_chunk & ~0x7);
while (len) {
size_t added = 0;
chunk = min(len, max_chunk);
len -= chunk;
dst = dbi->tx_buf9;
if (chunk < 8) {
u8 val, carry = 0;
/* Data: pad no-op's (zeroes) at end of block */
memset(dst, 0, 9);
if (swap_bytes) {
for (i = 1; i < (chunk + 1); i++) {
val = src[1];
*dst++ = carry | BIT(8 - i) | (val >> i);
carry = val << (8 - i);
i++;
val = src[0];
*dst++ = carry | BIT(8 - i) | (val >> i);
carry = val << (8 - i);
src += 2;
}
*dst++ = carry;
} else {
for (i = 1; i < (chunk + 1); i++) {
val = *src++;
*dst++ = carry | BIT(8 - i) | (val >> i);
carry = val << (8 - i);
}
*dst++ = carry;
}
chunk = 8;
added = 1;
} else {
for (i = 0; i < chunk; i += 8) {
if (swap_bytes) {
*dst++ = BIT(7) | (src[1] >> 1);
*dst++ = (src[1] << 7) | BIT(6) | (src[0] >> 2);
*dst++ = (src[0] << 6) | BIT(5) | (src[3] >> 3);
*dst++ = (src[3] << 5) | BIT(4) | (src[2] >> 4);
*dst++ = (src[2] << 4) | BIT(3) | (src[5] >> 5);
*dst++ = (src[5] << 3) | BIT(2) | (src[4] >> 6);
*dst++ = (src[4] << 2) | BIT(1) | (src[7] >> 7);
*dst++ = (src[7] << 1) | BIT(0);
*dst++ = src[6];
} else {
*dst++ = BIT(7) | (src[0] >> 1);
*dst++ = (src[0] << 7) | BIT(6) | (src[1] >> 2);
*dst++ = (src[1] << 6) | BIT(5) | (src[2] >> 3);
*dst++ = (src[2] << 5) | BIT(4) | (src[3] >> 4);
*dst++ = (src[3] << 4) | BIT(3) | (src[4] >> 5);
*dst++ = (src[4] << 3) | BIT(2) | (src[5] >> 6);
*dst++ = (src[5] << 2) | BIT(1) | (src[6] >> 7);
*dst++ = (src[6] << 1) | BIT(0);
*dst++ = src[7];
}
src += 8;
added++;
}
}
tr.len = chunk + added;
ret = spi_sync(spi, &m);
if (ret)
return ret;
}
return 0;
}
static int mipi_dbi_spi1_transfer(struct mipi_dbi *dbi, int dc,
const void *buf, size_t len,
unsigned int bpw)
{
struct spi_device *spi = dbi->spi;
struct spi_transfer tr = {
.bits_per_word = 9,
};
const u16 *src16 = buf;
const u8 *src8 = buf;
struct spi_message m;
size_t max_chunk;
u16 *dst16;
int ret;
if (!spi_is_bpw_supported(spi, 9))
return mipi_dbi_spi1e_transfer(dbi, dc, buf, len, bpw);
tr.speed_hz = mipi_dbi_spi_cmd_max_speed(spi, len);
max_chunk = dbi->tx_buf9_len;
dst16 = dbi->tx_buf9;
if (drm_debug_enabled(DRM_UT_DRIVER))
pr_debug("[drm:%s] dc=%d, max_chunk=%zu, transfers:\n",
__func__, dc, max_chunk);
max_chunk = min(max_chunk / 2, len);
spi_message_init_with_transfers(&m, &tr, 1);
tr.tx_buf = dst16;
while (len) {
size_t chunk = min(len, max_chunk);
unsigned int i;
if (bpw == 16) {
for (i = 0; i < (chunk * 2); i += 2) {
dst16[i] = *src16 >> 8;
dst16[i + 1] = *src16++ & 0xFF;
if (dc) {
dst16[i] |= 0x0100;
dst16[i + 1] |= 0x0100;
}
}
} else {
for (i = 0; i < chunk; i++) {
dst16[i] = *src8++;
if (dc)
dst16[i] |= 0x0100;
}
}
tr.len = chunk * 2;
len -= chunk;
ret = spi_sync(spi, &m);
if (ret)
return ret;
}
return 0;
}
static int mipi_dbi_typec1_command_read(struct mipi_dbi *dbi, u8 *cmd,
u8 *data, size_t len)
{
struct spi_device *spi = dbi->spi;
u32 speed_hz = min_t(u32, MIPI_DBI_MAX_SPI_READ_SPEED,
spi->max_speed_hz / 2);
struct spi_transfer tr[2] = {
{
.speed_hz = speed_hz,
.bits_per_word = 9,
.tx_buf = dbi->tx_buf9,
.len = 2,
}, {
.speed_hz = speed_hz,
.bits_per_word = 8,
.len = len,
.rx_buf = data,
},
};
struct spi_message m;
u16 *dst16;
int ret;
if (!len)
return -EINVAL;
if (!spi_is_bpw_supported(spi, 9)) {
/*
* FIXME: implement something like mipi_dbi_spi1e_transfer() but
* for reads using emulation.
*/
dev_err(&spi->dev,
"reading on host not supporting 9 bpw not yet implemented\n");
return -EOPNOTSUPP;
}
/*
* Turn the 8bit command into a 16bit version of the command in the
* buffer. Only 9 bits of this will be used when executing the actual
* transfer.
*/
dst16 = dbi->tx_buf9;
dst16[0] = *cmd;
spi_message_init_with_transfers(&m, tr, ARRAY_SIZE(tr));
ret = spi_sync(spi, &m);
if (!ret)
MIPI_DBI_DEBUG_COMMAND(*cmd, data, len);
return ret;
}
static int mipi_dbi_typec1_command(struct mipi_dbi *dbi, u8 *cmd,
u8 *parameters, size_t num)
{
unsigned int bpw = 8;
int ret;
if (mipi_dbi_command_is_read(dbi, *cmd))
return mipi_dbi_typec1_command_read(dbi, cmd, parameters, num);
MIPI_DBI_DEBUG_COMMAND(*cmd, parameters, num);
ret = mipi_dbi_spi1_transfer(dbi, 0, cmd, 1, 8);
if (ret || !num)
return ret;
if (*cmd == MIPI_DCS_WRITE_MEMORY_START)
bpw = dbi->write_memory_bpw;
return mipi_dbi_spi1_transfer(dbi, 1, parameters, num, bpw);
}
/* MIPI DBI Type C Option 3 */
static int mipi_dbi_typec3_command_read(struct mipi_dbi *dbi, u8 *cmd,
u8 *data, size_t len)
{
struct spi_device *spi = dbi->spi;
u32 speed_hz = min_t(u32, MIPI_DBI_MAX_SPI_READ_SPEED,
spi->max_speed_hz / 2);
struct spi_transfer tr[2] = {
{
.speed_hz = speed_hz,
.tx_buf = cmd,
.len = 1,
}, {
.speed_hz = speed_hz,
.len = len,
},
};
struct spi_message m;
u8 *buf;
int ret;
if (!len)
return -EINVAL;
/*
* Support non-standard 24-bit and 32-bit Nokia read commands which
* start with a dummy clock, so we need to read an extra byte.
*/
if (*cmd == MIPI_DCS_GET_DISPLAY_ID ||
*cmd == MIPI_DCS_GET_DISPLAY_STATUS) {
if (!(len == 3 || len == 4))
return -EINVAL;
tr[1].len = len + 1;
}
buf = kmalloc(tr[1].len, GFP_KERNEL);
if (!buf)
return -ENOMEM;
tr[1].rx_buf = buf;
spi_bus_lock(spi->controller);
gpiod_set_value_cansleep(dbi->dc, 0);
spi_message_init_with_transfers(&m, tr, ARRAY_SIZE(tr));
ret = spi_sync_locked(spi, &m);
spi_bus_unlock(spi->controller);
if (ret)
goto err_free;
if (tr[1].len == len) {
memcpy(data, buf, len);
} else {
unsigned int i;
for (i = 0; i < len; i++)
data[i] = (buf[i] << 1) | (buf[i + 1] >> 7);
}
MIPI_DBI_DEBUG_COMMAND(*cmd, data, len);
err_free:
kfree(buf);
return ret;
}
static int mipi_dbi_typec3_command(struct mipi_dbi *dbi, u8 *cmd,
u8 *par, size_t num)
{
struct spi_device *spi = dbi->spi;
unsigned int bpw = 8;
u32 speed_hz;
int ret;
if (mipi_dbi_command_is_read(dbi, *cmd))
return mipi_dbi_typec3_command_read(dbi, cmd, par, num);
MIPI_DBI_DEBUG_COMMAND(*cmd, par, num);
spi_bus_lock(spi->controller);
gpiod_set_value_cansleep(dbi->dc, 0);
speed_hz = mipi_dbi_spi_cmd_max_speed(spi, 1);
ret = mipi_dbi_spi_transfer(spi, speed_hz, 8, cmd, 1);
spi_bus_unlock(spi->controller);
if (ret || !num)
return ret;
if (*cmd == MIPI_DCS_WRITE_MEMORY_START)
bpw = dbi->write_memory_bpw;
spi_bus_lock(spi->controller);
gpiod_set_value_cansleep(dbi->dc, 1);
speed_hz = mipi_dbi_spi_cmd_max_speed(spi, num);
ret = mipi_dbi_spi_transfer(spi, speed_hz, bpw, par, num);
spi_bus_unlock(spi->controller);
return ret;
}
/**
* mipi_dbi_spi_init - Initialize MIPI DBI SPI interface
* @spi: SPI device
* @dbi: MIPI DBI structure to initialize
* @dc: D/C gpio (optional)
*
* This function sets &mipi_dbi->command, enables &mipi_dbi->read_commands for the
* usual read commands. It should be followed by a call to mipi_dbi_dev_init() or
* a driver-specific init.
*
* If @dc is set, a Type C Option 3 interface is assumed, if not
* Type C Option 1.
*
* If the command is %MIPI_DCS_WRITE_MEMORY_START and the pixel format is RGB565, endianness has
* to be taken into account. The MIPI DBI serial interface is big endian and framebuffers are
* assumed stored in memory as little endian (%DRM_FORMAT_BIG_ENDIAN is not supported).
*
* This is how endianness is handled:
*
* Option 1 (D/C as a bit): The buffer is sent on the wire byte by byte so the 16-bit buffer is
* byteswapped before transfer.
*
* Option 3 (D/C as a gpio): If the SPI controller supports 16 bits per word the buffer can be
* sent as-is. If not the caller is responsible for swapping the bytes
* before calling mipi_dbi_command_buf() and the buffer is sent 8 bpw.
*
* This handling is optimised for %DRM_FORMAT_RGB565 framebuffers.
*
* If the interface is Option 1 and the SPI controller doesn't support 9 bits per word,
* the buffer is sent as 9x 8-bit words, padded with MIPI DCS no-op commands if necessary.
*
* Returns:
* Zero on success, negative error code on failure.
*/
int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *dbi,
struct gpio_desc *dc)
{
struct device *dev = &spi->dev;
int ret;
/*
* Even though it's not the SPI device that does DMA (the master does),
* the dma mask is necessary for the dma_alloc_wc() in the GEM code
* (e.g., drm_gem_dma_create()). The dma_addr returned will be a physical
* address which might be different from the bus address, but this is
* not a problem since the address will not be used.
* The virtual address is used in the transfer and the SPI core
* re-maps it on the SPI master device using the DMA streaming API
* (spi_map_buf()).
*/
if (!dev->coherent_dma_mask) {
ret = dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(32));
if (ret) {
dev_warn(dev, "Failed to set dma mask %d\n", ret);
return ret;
}
}
dbi->spi = spi;
dbi->read_commands = mipi_dbi_dcs_read_commands;
dbi->write_memory_bpw = 16;
if (dc) {
dbi->command = mipi_dbi_typec3_command;
dbi->dc = dc;
if (!spi_is_bpw_supported(spi, 16)) {
dbi->write_memory_bpw = 8;
dbi->swap_bytes = true;
}
} else {
dbi->command = mipi_dbi_typec1_command;
dbi->tx_buf9_len = SZ_16K;
dbi->tx_buf9 = devm_kmalloc(dev, dbi->tx_buf9_len, GFP_KERNEL);
if (!dbi->tx_buf9)
return -ENOMEM;
}
mutex_init(&dbi->cmdlock);
DRM_DEBUG_DRIVER("SPI speed: %uMHz\n", spi->max_speed_hz / 1000000);
return 0;
}
EXPORT_SYMBOL(mipi_dbi_spi_init);
/**
* mipi_dbi_spi_transfer - SPI transfer helper
* @spi: SPI device
* @speed_hz: Override speed (optional)
* @bpw: Bits per word
* @buf: Buffer to transfer
* @len: Buffer length
*
* This SPI transfer helper breaks up the transfer of @buf into chunks which
* the SPI controller driver can handle. The SPI bus must be locked when
* calling this.
*
* Returns:
* Zero on success, negative error code on failure.
*/
int mipi_dbi_spi_transfer(struct spi_device *spi, u32 speed_hz,
u8 bpw, const void *buf, size_t len)
{
size_t max_chunk = spi_max_transfer_size(spi);
struct spi_transfer tr = {
.bits_per_word = bpw,
.speed_hz = speed_hz,
};
struct spi_message m;
size_t chunk;
int ret;
/* In __spi_validate, there's a validation that no partial transfers
* are accepted (xfer->len % w_size must be zero).
* Here we align max_chunk to multiple of 2 (16bits),
* to prevent transfers from being rejected.
*/
max_chunk = ALIGN_DOWN(max_chunk, 2);
spi_message_init_with_transfers(&m, &tr, 1);
while (len) {
chunk = min(len, max_chunk);
tr.tx_buf = buf;
tr.len = chunk;
buf += chunk;
len -= chunk;
ret = spi_sync_locked(spi, &m);
if (ret)
return ret;
}
return 0;
}
EXPORT_SYMBOL(mipi_dbi_spi_transfer);
#endif /* CONFIG_SPI */
#ifdef CONFIG_DEBUG_FS
static ssize_t mipi_dbi_debugfs_command_write(struct file *file,
const char __user *ubuf,
size_t count, loff_t *ppos)
{
struct seq_file *m = file->private_data;
struct mipi_dbi_dev *dbidev = m->private;
u8 val, cmd = 0, parameters[64];
char *buf, *pos, *token;
int i, ret, idx;
if (!drm_dev_enter(&dbidev->drm, &idx))
return -ENODEV;
buf = memdup_user_nul(ubuf, count);
if (IS_ERR(buf)) {
ret = PTR_ERR(buf);
goto err_exit;
}
/* strip trailing whitespace */
for (i = count - 1; i > 0; i--)
if (isspace(buf[i]))
buf[i] = '\0';
else
break;
i = 0;
pos = buf;
while (pos) {
token = strsep(&pos, " ");
if (!token) {
ret = -EINVAL;
goto err_free;
}
ret = kstrtou8(token, 16, &val);
if (ret < 0)
goto err_free;
if (token == buf)
cmd = val;
else
parameters[i++] = val;
if (i == 64) {
ret = -E2BIG;
goto err_free;
}
}
ret = mipi_dbi_command_buf(&dbidev->dbi, cmd, parameters, i);
err_free:
kfree(buf);
err_exit:
drm_dev_exit(idx);
return ret < 0 ? ret : count;
}
static int mipi_dbi_debugfs_command_show(struct seq_file *m, void *unused)
{
struct mipi_dbi_dev *dbidev = m->private;
struct mipi_dbi *dbi = &dbidev->dbi;
u8 cmd, val[4];
int ret, idx;
size_t len;
if (!drm_dev_enter(&dbidev->drm, &idx))
return -ENODEV;
for (cmd = 0; cmd < 255; cmd++) {
if (!mipi_dbi_command_is_read(dbi, cmd))
continue;
switch (cmd) {
case MIPI_DCS_READ_MEMORY_START:
case MIPI_DCS_READ_MEMORY_CONTINUE:
len = 2;
break;
case MIPI_DCS_GET_DISPLAY_ID:
len = 3;
break;
case MIPI_DCS_GET_DISPLAY_STATUS:
len = 4;
break;
default:
len = 1;
break;
}
seq_printf(m, "%02x: ", cmd);
ret = mipi_dbi_command_buf(dbi, cmd, val, len);
if (ret) {
seq_puts(m, "XX\n");
continue;
}
seq_printf(m, "%*phN\n", (int)len, val);
}
drm_dev_exit(idx);
return 0;
}
static int mipi_dbi_debugfs_command_open(struct inode *inode,
struct file *file)
{
return single_open(file, mipi_dbi_debugfs_command_show,
inode->i_private);
}
static const struct file_operations mipi_dbi_debugfs_command_fops = {
.owner = THIS_MODULE,
.open = mipi_dbi_debugfs_command_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.write = mipi_dbi_debugfs_command_write,
};
/**
* mipi_dbi_debugfs_init - Create debugfs entries
* @minor: DRM minor
*
* This function creates a 'command' debugfs file for sending commands to the
* controller or getting the read command values.
* Drivers can use this as their &drm_driver->debugfs_init callback.
*
*/
void mipi_dbi_debugfs_init(struct drm_minor *minor)
{
struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(minor->dev);
umode_t mode = S_IFREG | S_IWUSR;
if (dbidev->dbi.read_commands)
mode |= S_IRUGO;
debugfs_create_file("command", mode, minor->debugfs_root, dbidev,
&mipi_dbi_debugfs_command_fops);
}
EXPORT_SYMBOL(mipi_dbi_debugfs_init);
#endif
MODULE_DESCRIPTION("MIPI Display Bus Interface (DBI) LCD controller support");
MODULE_LICENSE("GPL");
Codebase Browser
linux