[PATCH v4 3/7] drm/tinydrm: Add MIPI DBI support

Noralf Trønnes
2017-02-11T18:50:41Z

Add support for MIPI DBI compatible controllers.
Interface type C option 1 and 3 are supported (SPI).

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Thierry Reding <treding@nvidia.com>
---

Changes since version 3:
- Use #if IS_ENABLED(CONFIG_SPI) instead of #ifdef to handle tristate

Documentation/gpu/tinydrm.rst | 12 +
drivers/gpu/drm/tinydrm/Kconfig | 3 +
drivers/gpu/drm/tinydrm/Makefile | 3 +
drivers/gpu/drm/tinydrm/mipi-dbi.c | 1005 ++++++++++++++++++++++++++++++++++++
include/drm/tinydrm/mipi-dbi.h | 107 ++++
5 files changed, 1130 insertions(+)
create mode 100644 drivers/gpu/drm/tinydrm/mipi-dbi.c
create mode 100644 include/drm/tinydrm/mipi-dbi.h

diff --git a/Documentation/gpu/tinydrm.rst b/Documentation/gpu/tinydrm.rst
index fb256d2..a913644 100644
--- a/Documentation/gpu/tinydrm.rst
+++ b/Documentation/gpu/tinydrm.rst
@@ -28,3 +28,15 @@ Additional helpers

.. kernel-doc:: drivers/gpu/drm/tinydrm/core/tinydrm-helpers.c
:export:
+
+MIPI DBI Compatible Controllers
+===============================
+
+.. kernel-doc:: drivers/gpu/drm/tinydrm/mipi-dbi.c
+ :doc: overview
+
+.. kernel-doc:: include/drm/tinydrm/mipi-dbi.h
+ :internal:
+
+.. kernel-doc:: drivers/gpu/drm/tinydrm/mipi-dbi.c
+ :export:
diff --git a/drivers/gpu/drm/tinydrm/Kconfig b/drivers/gpu/drm/tinydrm/Kconfig
index adf3626..e00bcfc 100644
--- a/drivers/gpu/drm/tinydrm/Kconfig
+++ b/drivers/gpu/drm/tinydrm/Kconfig
@@ -8,3 +8,6 @@ menuconfig DRM_TINYDRM
help
Choose this option if you have a tinydrm supported display.
If M is selected the module will be called tinydrm.
+
+config TINYDRM_MIPI_DBI
+ tristate
diff --git a/drivers/gpu/drm/tinydrm/Makefile b/drivers/gpu/drm/tinydrm/Makefile
index 7476ed1..fe5d4c6 100644
--- a/drivers/gpu/drm/tinydrm/Makefile
+++ b/drivers/gpu/drm/tinydrm/Makefile
@@ -1 +1,4 @@
obj-$(CONFIG_DRM_TINYDRM) += core/
+
+# Controllers
+obj-$(CONFIG_TINYDRM_MIPI_DBI) += mipi-dbi.o
diff --git a/drivers/gpu/drm/tinydrm/mipi-dbi.c b/drivers/gpu/drm/tinydrm/mipi-dbi.c
new file mode 100644
index 0000000..07d49ba
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/mipi-dbi.c
@@ -0,0 +1,1005 @@
+/*
+ * 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 <drm/tinydrm/mipi-dbi.h>
+#include <drm/tinydrm/tinydrm-helpers.h>
+#include <linux/debugfs.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 <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, 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);
+
+static int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
+ struct drm_clip_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));
+ return -EINVAL;
+ }
+
+ if (import_attach)
+ ret = dma_buf_end_cpu_access(import_attach->dmabuf,
+ DMA_FROM_DEVICE);
+ return ret;
+}
+
+static int mipi_dbi_fb_dirty(struct drm_framebuffer *fb,
+ struct drm_file *file_priv,
+ unsigned int flags, unsigned int color,
+ struct drm_clip_rect *clips,
+ unsigned int num_clips)
+{
+ struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
+ struct tinydrm_device *tdev = fb->dev->dev_private;
+ struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+ bool swap = mipi->swap_bytes;
+ struct drm_clip_rect clip;
+ int ret = 0;
+ bool full;
+ void *tr;
+
+ mutex_lock(&tdev->dirty_lock);
+
+ if (!mipi->enabled)
+ goto out_unlock;
+
+ /* fbdev can flush even when we're not interested */
+ if (tdev->pipe.plane.fb != fb)
+ goto out_unlock;
+
+ full = tinydrm_merge_clips(&clip, clips, num_clips, flags,
+ fb->width, fb->height);
+
+ DRM_DEBUG("Flushing [FB:%d] x1=%u, x2=%u, y1=%u, y2=%u\n", fb->base.id,
+ clip.x1, clip.x2, clip.y1, clip.y2);
+
+ if (!mipi->dc || !full || swap ||
+ fb->format->format == DRM_FORMAT_XRGB8888) {
+ tr = mipi->tx_buf;
+ ret = mipi_dbi_buf_copy(mipi->tx_buf, fb, &clip, swap);
+ if (ret)
+ goto out_unlock;
+ } else {
+ tr = cma_obj->vaddr;
+ }
+
+ mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,
+ (clip.x1 >> 8) & 0xFF, clip.x1 & 0xFF,
+ (clip.x2 >> 8) & 0xFF, (clip.x2 - 1) & 0xFF);
+ mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS,
+ (clip.y1 >> 8) & 0xFF, clip.y1 & 0xFF,
+ (clip.y2 >> 8) & 0xFF, (clip.y2 - 1) & 0xFF);
+
+ ret = mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START, tr,
+ (clip.x2 - clip.x1) * (clip.y2 - clip.y1) * 2);
+
+out_unlock:
+ mutex_unlock(&tdev->dirty_lock);
+
+ if (ret)
+ dev_err_once(fb->dev->dev, "Failed to update display %d\n",
+ ret);
+
+ return ret;
+}
+
+static const struct drm_framebuffer_funcs mipi_dbi_fb_funcs = {
+ .destroy = drm_fb_cma_destroy,
+ .create_handle = drm_fb_cma_create_handle,
+ .dirty = mipi_dbi_fb_dirty,
+};
+
+/**
+ * mipi_dbi_pipe_enable - MIPI DBI pipe enable helper
+ * @pipe: Display pipe
+ * @crtc_state: CRTC state
+ *
+ * This function enables backlight. Drivers can use this as their
+ * &drm_simple_display_pipe_funcs->enable callback.
+ */
+void mipi_dbi_pipe_enable(struct drm_simple_display_pipe *pipe,
+ struct drm_crtc_state *crtc_state)
+{
+ struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
+ struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+ struct drm_framebuffer *fb = pipe->plane.fb;
+
+ DRM_DEBUG_KMS("\n");
+
+ mipi->enabled = true;
+ if (fb)
+ fb->funcs->dirty(fb, NULL, 0, 0, NULL, 0);
+
+ tinydrm_enable_backlight(mipi->backlight);
+}
+EXPORT_SYMBOL(mipi_dbi_pipe_enable);
+
+static void mipi_dbi_blank(struct mipi_dbi *mipi)
+{
+ struct drm_device *drm = mipi->tinydrm.drm;
+ u16 height = drm->mode_config.min_height;
+ u16 width = drm->mode_config.min_width;
+ size_t len = width * height * 2;
+
+ memset(mipi->tx_buf, 0, len);
+
+ mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS, 0, 0,
+ (width >> 8) & 0xFF, (width - 1) & 0xFF);
+ mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS, 0, 0,
+ (height >> 8) & 0xFF, (height - 1) & 0xFF);
+ mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START,
+ (u8 *)mipi->tx_buf, len);
+}
+
+/**
+ * mipi_dbi_pipe_disable - MIPI DBI pipe disable helper
+ * @pipe: Display pipe
+ *
+ * This function disables backlight if present or if not the
+ * display memory is blanked. 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 tinydrm_device *tdev = pipe_to_tinydrm(pipe);
+ struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+
+ DRM_DEBUG_KMS("\n");
+
+ mipi->enabled = false;
+
+ if (mipi->backlight)
+ tinydrm_disable_backlight(mipi->backlight);
+ else
+ mipi_dbi_blank(mipi);
+}
+EXPORT_SYMBOL(mipi_dbi_pipe_disable);
+
+static const uint32_t mipi_dbi_formats[] = {
+ DRM_FORMAT_RGB565,
+ DRM_FORMAT_XRGB8888,
+};
+
+/**
+ * mipi_dbi_init - MIPI DBI initialization
+ * @dev: Parent device
+ * @mipi: &mipi_dbi structure to initialize
+ * @pipe_funcs: Display pipe functions
+ * @driver: DRM driver
+ * @mode: Display mode
+ * @rotation: Initial rotation in degrees Counter Clock Wise
+ *
+ * This function initializes a &mipi_dbi structure and it's underlying
+ * @tinydrm_device. It also sets up the display pipeline.
+ *
+ * Supported formats: Native RGB565 and emulated XRGB8888.
+ *
+ * Objects created by this function will be automatically freed on driver
+ * detach (devres).
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int mipi_dbi_init(struct device *dev, struct mipi_dbi *mipi,
+ const struct drm_simple_display_pipe_funcs *pipe_funcs,
+ struct drm_driver *driver,
+ const struct drm_display_mode *mode, unsigned int rotation)
+{
+ size_t bufsize = mode->vdisplay * mode->hdisplay * sizeof(u16);
+ struct tinydrm_device *tdev = &mipi->tinydrm;
+ int ret;
+
+ if (!mipi->command)
+ return -EINVAL;
+
+ mutex_init(&mipi->cmdlock);
+
+ mipi->tx_buf = devm_kmalloc(dev, bufsize, GFP_KERNEL);
+ if (!mipi->tx_buf)
+ return -ENOMEM;
+
+ ret = devm_tinydrm_init(dev, tdev, &mipi_dbi_fb_funcs, driver);
+ if (ret)
+ return ret;
+
+ /* TODO: Maybe add DRM_MODE_CONNECTOR_SPI */
+ ret = tinydrm_display_pipe_init(tdev, pipe_funcs,
+ DRM_MODE_CONNECTOR_VIRTUAL,
+ mipi_dbi_formats,
+ ARRAY_SIZE(mipi_dbi_formats), mode,
+ rotation);
+ if (ret)
+ return ret;
+
+ tdev->drm->mode_config.preferred_depth = 16;
+ mipi->rotation = rotation;
+
+ drm_mode_config_reset(tdev->drm);
+
+ DRM_DEBUG_KMS("preferred_depth=%u, rotation = %u\n",
+ tdev->drm->mode_config.preferred_depth, rotation);
+
+ return 0;
+}
+EXPORT_SYMBOL(mipi_dbi_init);
+
+/**
+ * mipi_dbi_hw_reset - Hardware reset of controller
+ * @mipi: MIPI DBI structure
+ *
+ * Reset controller if the &mipi_dbi->reset gpio is set.
+ */
+void mipi_dbi_hw_reset(struct mipi_dbi *mipi)
+{
+ if (!mipi->reset)
+ return;
+
+ gpiod_set_value_cansleep(mipi->reset, 0);
+ msleep(20);
+ gpiod_set_value_cansleep(mipi->reset, 1);
+ msleep(120);
+}
+EXPORT_SYMBOL(mipi_dbi_hw_reset);
+
+/**
+ * mipi_dbi_display_is_on - Check if display is on
+ * @mipi: 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 *mipi)
+{
+ u8 val;
+
+ if (mipi_dbi_command_read(mipi, MIPI_DCS_GET_POWER_MODE, &val))
+ return false;
+
+ val &= ~DCS_POWER_MODE_RESERVED_MASK;
+
+ 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);
+
+#if IS_ENABLED(CONFIG_SPI)
+
+/*
+ * 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.
+ */
+static 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);
+}
+
+/*
+ * 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 *mipi, int dc,
+ const void *buf, size_t len,
+ unsigned int bpw)
+{
+ bool swap_bytes = (bpw == 16 && tinydrm_machine_little_endian());
+ size_t chunk, max_chunk = mipi->tx_buf9_len;
+ struct spi_device *spi = mipi->spi;
+ struct spi_transfer tr = {
+ .tx_buf = mipi->tx_buf9,
+ .bits_per_word = 8,
+ };
+ struct spi_message m;
+ const u8 *src = buf;
+ int i, ret;
+ u8 *dst;
+
+ if (drm_debug & 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 = mipi->tx_buf9;
+ memset(dst, 0, 9);
+ dst[8] = *src;
+ tr.len = 9;
+
+ tinydrm_dbg_spi_message(spi, &m);
+
+ 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 = mipi->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;
+
+ tinydrm_dbg_spi_message(spi, &m);
+ ret = spi_sync(spi, &m);
+ if (ret)
+ return ret;
+ };
+
+ return 0;
+}
+
+static int mipi_dbi_spi1_transfer(struct mipi_dbi *mipi, int dc,
+ const void *buf, size_t len,
+ unsigned int bpw)
+{
+ struct spi_device *spi = mipi->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 (!tinydrm_spi_bpw_supported(spi, 9))
+ return mipi_dbi_spi1e_transfer(mipi, dc, buf, len, bpw);
+
+ tr.speed_hz = mipi_dbi_spi_cmd_max_speed(spi, len);
+ max_chunk = mipi->tx_buf9_len;
+ dst16 = mipi->tx_buf9;
+
+ if (drm_debug & 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 && tinydrm_machine_little_endian()) {
+ 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;
+ len -= chunk;
+
+ tinydrm_dbg_spi_message(spi, &m);
+ ret = spi_sync(spi, &m);
+ if (ret)
+ return ret;
+ };
+
+ return 0;
+}
+
+static int mipi_dbi_typec1_command(struct mipi_dbi *mipi, u8 cmd,
+ u8 *parameters, size_t num)
+{
+ unsigned int bpw = (cmd == MIPI_DCS_WRITE_MEMORY_START) ? 16 : 8;
+ int ret;
+
+ if (mipi_dbi_command_is_read(mipi, cmd))
+ return -ENOTSUPP;
+
+ MIPI_DBI_DEBUG_COMMAND(cmd, parameters, num);
+
+ ret = mipi_dbi_spi1_transfer(mipi, 0, &cmd, 1, 8);
+ if (ret || !num)
+ return ret;
+
+ return mipi_dbi_spi1_transfer(mipi, 1, parameters, num, bpw);
+}
+
+/* MIPI DBI Type C Option 3 */
+
+static int mipi_dbi_typec3_command_read(struct mipi_dbi *mipi, u8 cmd,
+ u8 *data, size_t len)
+{
+ struct spi_device *spi = mipi->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;
+ gpiod_set_value_cansleep(mipi->dc, 0);
+
+ spi_message_init_with_transfers(&m, tr, ARRAY_SIZE(tr));
+ ret = spi_sync(spi, &m);
+ if (ret)
+ goto err_free;
+
+ tinydrm_dbg_spi_message(spi, &m);
+
+ 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] & BIT(7));
+ }
+
+ MIPI_DBI_DEBUG_COMMAND(cmd, data, len);
+
+err_free:
+ kfree(buf);
+
+ return ret;
+}
+
+static int mipi_dbi_typec3_command(struct mipi_dbi *mipi, u8 cmd,
+ u8 *par, size_t num)
+{
+ struct spi_device *spi = mipi->spi;
+ unsigned int bpw = 8;
+ u32 speed_hz;
+ int ret;
+
+ if (mipi_dbi_command_is_read(mipi, cmd))
+ return mipi_dbi_typec3_command_read(mipi, cmd, par, num);
+
+ MIPI_DBI_DEBUG_COMMAND(cmd, par, num);
+
+ gpiod_set_value_cansleep(mipi->dc, 0);
+ speed_hz = mipi_dbi_spi_cmd_max_speed(spi, 1);
+ ret = tinydrm_spi_transfer(spi, speed_hz, NULL, 8, &cmd, 1);
+ if (ret || !num)
+ return ret;
+
+ if (cmd == MIPI_DCS_WRITE_MEMORY_START && !mipi->swap_bytes)
+ bpw = 16;
+
+ gpiod_set_value_cansleep(mipi->dc, 1);
+ speed_hz = mipi_dbi_spi_cmd_max_speed(spi, num);
+
+ return tinydrm_spi_transfer(spi, speed_hz, NULL, bpw, par, num);
+}
+
+/**
+ * mipi_dbi_spi_init - Initialize MIPI DBI SPI interfaced controller
+ * @spi: SPI device
+ * @dc: D/C gpio (optional)
+ * @mipi: &mipi_dbi structure to initialize
+ * @pipe_funcs: Display pipe functions
+ * @driver: DRM driver
+ * @mode: Display mode
+ * @rotation: Initial rotation in degrees Counter Clock Wise
+ *
+ * This function sets &mipi_dbi->command, enables &mipi->read_commands for the
+ * usual read commands and initializes @mipi using mipi_dbi_init().
+ *
+ * If @dc is set, a Type C Option 3 interface is assumed, if not
+ * Type C Option 1.
+ *
+ * If the SPI master driver doesn't support the necessary bits per word,
+ * the following transformation is used:
+ *
+ * - 9-bit: reorder buffer as 9x 8-bit words, padded with no-op command.
+ * - 16-bit: if big endian send as 8-bit, if little endian swap bytes
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *mipi,
+ struct gpio_desc *dc,
+ const struct drm_simple_display_pipe_funcs *pipe_funcs,
+ struct drm_driver *driver,
+ const struct drm_display_mode *mode,
+ unsigned int rotation)
+{
+ size_t tx_size = tinydrm_spi_max_transfer_size(spi, 0);
+ struct device *dev = &spi->dev;
+ int ret;
+
+ if (tx_size < 16) {
+ DRM_ERROR("SPI transmit buffer too small: %zu\n", tx_size);
+ return -EINVAL;
+ }
+
+ /*
+ * 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
+ * drm_gem_cma_create(). The dma_addr returned will be a physical
+ * adddress 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;
+ }
+ }
+
+ mipi->spi = spi;
+ mipi->read_commands = mipi_dbi_dcs_read_commands;
+
+ if (dc) {
+ mipi->command = mipi_dbi_typec3_command;
+ mipi->dc = dc;
+ if (tinydrm_machine_little_endian() &&
+ !tinydrm_spi_bpw_supported(spi, 16))
+ mipi->swap_bytes = true;
+ } else {
+ mipi->command = mipi_dbi_typec1_command;
+ mipi->tx_buf9_len = tx_size;
+ mipi->tx_buf9 = devm_kmalloc(dev, tx_size, GFP_KERNEL);
+ if (!mipi->tx_buf9)
+ return -ENOMEM;
+ }
+
+ return mipi_dbi_init(dev, mipi, pipe_funcs, driver, mode, rotation);
+}
+EXPORT_SYMBOL(mipi_dbi_spi_init);
+
+#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 *mipi = m->private;
+ u8 val, cmd, parameters[64];
+ char *buf, *pos, *token;
+ unsigned int i;
+ int ret;
+
+ buf = memdup_user_nul(ubuf, count);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ /* 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(mipi, cmd, parameters, i);
+
+err_free:
+ kfree(buf);
+
+ return ret < 0 ? ret : count;
+}
+
+static int mipi_dbi_debugfs_command_show(struct seq_file *m, void *unused)
+{
+ struct mipi_dbi *mipi = m->private;
+ u8 cmd, val[4];
+ size_t len, i;
+ int ret;
+
+ for (cmd = 0; cmd < 255; cmd++) {
+ if (!mipi_dbi_command_is_read(mipi, 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(mipi, cmd, val, len);
+ if (ret) {
+ seq_puts(m, "XX\n");
+ continue;
+ }
+
+ for (i = 0; i < len; i++)
+ seq_printf(m, "%02x", val[i]);
+ seq_puts(m, "\n");
+ }
+
+ 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,
+};
+
+static const struct drm_info_list mipi_dbi_debugfs_list[] = {
+ { "fb", drm_fb_cma_debugfs_show, 0 },
+};
+
+/**
+ * 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.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int mipi_dbi_debugfs_init(struct drm_minor *minor)
+{
+ struct tinydrm_device *tdev = minor->dev->dev_private;
+ struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+ umode_t mode = S_IFREG | S_IWUSR;
+
+ if (mipi->read_commands)
+ mode |= S_IRUGO;
+ debugfs_create_file("command", mode, minor->debugfs_root, mipi,
+ &mipi_dbi_debugfs_command_fops);
+
+ return drm_debugfs_create_files(mipi_dbi_debugfs_list,
+ ARRAY_SIZE(mipi_dbi_debugfs_list),
+ minor->debugfs_root, minor);
+}
+EXPORT_SYMBOL(mipi_dbi_debugfs_init);
+
+#endif
+
+MODULE_LICENSE("GPL");
diff --git a/include/drm/tinydrm/mipi-dbi.h b/include/drm/tinydrm/mipi-dbi.h
new file mode 100644
index 0000000..d137b16
--- /dev/null
+++ b/include/drm/tinydrm/mipi-dbi.h
@@ -0,0 +1,107 @@
+/*
+ * 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.
+ */
+
+#ifndef __LINUX_MIPI_DBI_H
+#define __LINUX_MIPI_DBI_H
+
+#include <drm/tinydrm/tinydrm.h>
+
+struct spi_device;
+struct gpio_desc;
+struct regulator;
+
+/**
+ * struct mipi_dbi - MIPI DBI controller
+ * @tinydrm: tinydrm base
+ * @spi: SPI device
+ * @enabled: Pipeline is enabled
+ * @cmdlock: Command lock
+ * @command: Bus specific callback executing commands.
+ * @read_commands: Array of read commands terminated by a zero entry.
+ * Reading is disabled if this is NULL.
+ * @dc: Optional D/C gpio.
+ * @tx_buf: Buffer used for transfer (copy clip rect area)
+ * @tx_buf9: Buffer used for Option 1 9-bit conversion
+ * @tx_buf9_len: Size of tx_buf9.
+ * @swap_bytes: Swap bytes in buffer before transfer
+ * @reset: Optional reset gpio
+ * @rotation: initial rotation in degrees Counter Clock Wise
+ * @backlight: backlight device (optional)
+ * @regulator: power regulator (optional)
+ */
+struct mipi_dbi {
+ struct tinydrm_device tinydrm;
+ struct spi_device *spi;
+ bool enabled;
+ struct mutex cmdlock;
+ int (*command)(struct mipi_dbi *mipi, u8 cmd, u8 *param, size_t num);
+ const u8 *read_commands;
+ struct gpio_desc *dc;
+ u16 *tx_buf;
+ void *tx_buf9;
+ size_t tx_buf9_len;
+ bool swap_bytes;
+ struct gpio_desc *reset;
+ unsigned int rotation;
+ struct backlight_device *backlight;
+ struct regulator *regulator;
+};
+
+static inline struct mipi_dbi *
+mipi_dbi_from_tinydrm(struct tinydrm_device *tdev)
+{
+ return container_of(tdev, struct mipi_dbi, tinydrm);
+}
+
+int mipi_dbi_spi_init(struct spi_device *spi, struct mipi_dbi *mipi,
+ struct gpio_desc *dc,
+ const struct drm_simple_display_pipe_funcs *pipe_funcs,
+ struct drm_driver *driver,
+ const struct drm_display_mode *mode,
+ unsigned int rotation);
+int mipi_dbi_init(struct device *dev, struct mipi_dbi *mipi,
+ const struct drm_simple_display_pipe_funcs *pipe_funcs,
+ struct drm_driver *driver,
+ const struct drm_display_mode *mode, unsigned int rotation);
+void mipi_dbi_pipe_enable(struct drm_simple_display_pipe *pipe,
+ struct drm_crtc_state *crtc_state);
+void mipi_dbi_pipe_disable(struct drm_simple_display_pipe *pipe);
+void mipi_dbi_hw_reset(struct mipi_dbi *mipi);
+bool mipi_dbi_display_is_on(struct mipi_dbi *mipi);
+
+int mipi_dbi_command_read(struct mipi_dbi *mipi, u8 cmd, u8 *val);
+int mipi_dbi_command_buf(struct mipi_dbi *mipi, u8 cmd, u8 *data, size_t len);
+
+/**
+ * mipi_dbi_command - MIPI DCS command with optional parameter(s)
+ * @mipi: MIPI structure
+ * @cmd: Command
+ * @seq...: Optional parameter(s)
+ *
+ * Send MIPI DCS command to the controller. Use mipi_dbi_command_read() for
+ * get/read.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+#define mipi_dbi_command(mipi, cmd, seq...) \
+({ \
+ u8 d[] = { seq }; \
+ mipi_dbi_command_buf(mipi, cmd, d, ARRAY_SIZE(d)); \
+})
+
+#ifdef CONFIG_DEBUG_FS
+int mipi_dbi_debugfs_init(struct drm_minor *minor);
+#else
+#define mipi_dbi_debugfs_init NULL
+#endif
+
+#endif /* __LINUX_MIPI_DBI_H */
--
2.10.2