path: root/drivers/gpu/drm/drm_mipi_dbi.c

// 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->