path: root/drivers/gpu/drm/tinydrm/mipi-dbi.c

/*
 * MIPI Display Bus Interface (DBI) LCD controller support
 *
 * Copyright 2016 Noralf Trønnes
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/dma-buf.h>
#include <linux/gpio/consumer.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>

#include <drm/drm_damage_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_cma_helper.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_gem_framebuffer_helper.h>
#include <drm/drm_vblank.h>
#include <drm/drm_rect.h>
#include <drm/tinydrm/mipi-dbi.h>
#include <drm/tinydrm/tinydrm-helpers.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 *mipi, u8 cmd)
{
	unsigned int i;

	if (!mipi->read_commands)
		return false;

	for (i = 0; i < 0xff; i++) {
		if (!mipi->read_commands[i])
			return false;
		if (cmd == mipi->read_commands[i])
			return true;
	}

	return false;
}

/**
 * mipi_dbi_command_read - MIPI DCS read command
 * @mipi: MIPI 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 *mipi, u8 cmd, u8 *val)
{
	if (!mipi->read_commands)
		return -EACCES;

	if (!mipi_dbi_command_is_read(mipi, cmd))
		return -EINVAL;

	return mipi_dbi_command_buf(mipi, cmd, val, 1);
}
EXPORT_SYMBOL(mipi_dbi_command_read);

/**
 * mipi_dbi_command_buf - MIPI DCS command with parameter(s) in an array
 * @mipi: MIPI 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 *mipi, u8 cmd, u8 *data, size_t len)
{
	int ret;

	mutex_lock(&mipi->cmdlock);
	ret = mipi->command(mipi, cmd, data, len);
	mutex_unlock(&mipi->cmdlock);

	return ret;
}
EXPORT_SYMBOL(mipi_dbi_command_buf);

/**
 * mipi_dbi_buf_copy - Copy a framebuffer, transforming it if necessary
 * @dst: The destination buffer
 * @fb: The source framebuffer
 * @clip: Clipping rectangle of the area to be copied
 * @swap: When true, swap MSB/LSB of 16-bit values
 *
 * Returns:
 * Zero on success, negative error code on failure.
 */
int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
		      struct drm_rect *clip, bool swap)
{
	struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
	struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
	struct drm_format_name_buf format_name;
	void *src = cma_obj->vaddr;
	int ret = 0;

	if (import_attach) {
		ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
					       DMA_FROM_DEVICE);
		if (ret)
			return ret;
	}

	switch (fb->format->format) {
	case DRM_FORMAT_RGB565:
		if (swap)
			tinydrm_swab16(dst, src, fb, clip);
		else
			tinydrm_memcpy(dst, src, fb, clip);
		break;
	case DRM_FORMAT_XRGB8888:
		tinydrm_xrgb8888_to_rgb565(dst, src, fb, clip, swap);
		break;
	default:
		dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
			     drm_get_format_name(fb->format->format,
						 &format_name