Re: [PATCH v4 3/5] drm/tinydrm: add support for LEGO MINDSTORMS EV3 LCD

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Den 09.08.2017 19.59, skrev Noralf Trønnes:

Den 07.08.2017 19.39, skrev David Lechner:
LEGO MINDSTORMS EV3 has an LCD with a ST7586 controller. This adds a new
module for the ST7586 controller with parameters for the LEGO MINDSTORMS
EV3 LCD display.

Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx>
---

This looks good, even I understand the pixel packing now :-)
Now we wait for the DT maintainers to have their say.

Reviewed-by: Noralf Trønnes <noralf@xxxxxxxxxxx>


Thanks, applied to drm-misc together with dt binding.

Noralf.

v4 changes:
* correct order for MAINTAINERS entry
* Drop code not used by LEGO EV3 (regulator, backlight, suspend/resume)
* Make gpios required
* Use lookup table for pixel packing algorithm
* Don't modify clip when used as function parameter
* Use roundup/rounddown macros


  MAINTAINERS                      |   6 +
  drivers/gpu/drm/tinydrm/Kconfig  |  10 +
  drivers/gpu/drm/tinydrm/Makefile |   1 +
drivers/gpu/drm/tinydrm/st7586.c | 428 +++++++++++++++++++++++++++++++++++++++
  4 files changed, 445 insertions(+)
  create mode 100644 drivers/gpu/drm/tinydrm/st7586.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a1e772e..19ca3e6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4380,6 +4380,12 @@ S:    Orphan / Obsolete
  F:    drivers/gpu/drm/sis/
  F:    include/uapi/drm/sis_drm.h
  +DRM DRIVER FOR SITRONIX ST7586 PANELS
+M:    David Lechner <david@xxxxxxxxxxxxxx>
+S:    Maintained
+F:    drivers/gpu/drm/tinydrm/st7586.c
+F:    Documentation/devicetree/bindings/display/st7586.txt
+
  DRM DRIVER FOR TDFX VIDEO CARDS
  S:    Orphan / Obsolete
  F:    drivers/gpu/drm/tdfx/
diff --git a/drivers/gpu/drm/tinydrm/Kconfig b/drivers/gpu/drm/tinydrm/Kconfig
index f17c3ca..2e790e7 100644
--- a/drivers/gpu/drm/tinydrm/Kconfig
+++ b/drivers/gpu/drm/tinydrm/Kconfig
@@ -32,3 +32,13 @@ config TINYDRM_REPAPER
        2.71" TFT EPD Panel (E2271CS021)
          If M is selected the module will be called repaper.
+
+config TINYDRM_ST7586
+    tristate "DRM support for Sitronix ST7586 display panels"
+    depends on DRM_TINYDRM && SPI
+    select TINYDRM_MIPI_DBI
+    help
+      DRM driver for the following Sitronix ST7586 panels:
+      * LEGO MINDSTORMS EV3
+
+      If M is selected the module will be called st7586.
diff --git a/drivers/gpu/drm/tinydrm/Makefile b/drivers/gpu/drm/tinydrm/Makefile
index 95bb4d4..0c184bd 100644
--- a/drivers/gpu/drm/tinydrm/Makefile
+++ b/drivers/gpu/drm/tinydrm/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_TINYDRM_MIPI_DBI)        += mipi-dbi.o
  # Displays
  obj-$(CONFIG_TINYDRM_MI0283QT)        += mi0283qt.o
  obj-$(CONFIG_TINYDRM_REPAPER)        += repaper.o
+obj-$(CONFIG_TINYDRM_ST7586)        += st7586.o
diff --git a/drivers/gpu/drm/tinydrm/st7586.c b/drivers/gpu/drm/tinydrm/st7586.c
new file mode 100644
index 0000000..1b39d3f
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/st7586.c
@@ -0,0 +1,428 @@
+/*
+ * DRM driver for Sitronix ST7586 panels
+ *
+ * Copyright 2017 David Lechner <david@xxxxxxxxxxxxxx>
+ *
+ * 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/delay.h>
+#include <linux/dma-buf.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/property.h>
+#include <linux/spi/spi.h>
+#include <video/mipi_display.h>
+
+#include <drm/tinydrm/mipi-dbi.h>
+#include <drm/tinydrm/tinydrm-helpers.h>
+
+/* controller-specific commands */
+#define ST7586_DISP_MODE_GRAY    0x38
+#define ST7586_DISP_MODE_MONO    0x39
+#define ST7586_ENABLE_DDRAM    0x3a
+#define ST7586_SET_DISP_DUTY    0xb0
+#define ST7586_SET_PART_DISP    0xb4
+#define ST7586_SET_NLINE_INV    0xb5
+#define ST7586_SET_VOP        0xc0
+#define ST7586_SET_BIAS_SYSTEM    0xc3
+#define ST7586_SET_BOOST_LEVEL    0xc4
+#define ST7586_SET_VOP_OFFSET    0xc7
+#define ST7586_ENABLE_ANALOG    0xd0
+#define ST7586_AUTO_READ_CTRL    0xd7
+#define ST7586_OTP_RW_CTRL    0xe0
+#define ST7586_OTP_CTRL_OUT    0xe1
+#define ST7586_OTP_READ        0xe3
+
+#define ST7586_DISP_CTRL_MX    BIT(6)
+#define ST7586_DISP_CTRL_MY    BIT(7)
+
+/*
+ * The ST7586 controller has an unusual pixel format where 2bpp grayscale is + * packed 3 pixels per byte with the first two pixels using 3 bits and the 3rd
+ * pixel using only 2 bits.
+ *
+ * |  D7  |  D6  |  D5  ||      |      || 2bpp |
+ * | (D4) | (D3) | (D2) ||  D1  |  D0  || GRAY |
+ * +------+------+------++------+------++------+
+ * |  1   |  1   |  1   ||  1   |  1   || 0  0 | black
+ * |  1   |  0   |  0   ||  1   |  0   || 0  1 | dark gray
+ * |  0   |  1   |  0   ||  0   |  1   || 1  0 | light gray
+ * |  0   |  0   |  0   ||  0   |  0   || 1  1 | white
+ */
+
+static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };
+
+static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
+                       struct drm_framebuffer *fb,
+                       struct drm_clip_rect *clip)
+{
+    size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
+    unsigned int x, y;
+    u8 *src, *buf, val;
+
+    buf = kmalloc(len, GFP_KERNEL);
+    if (!buf)
+        return;
+
+    tinydrm_xrgb8888_to_gray8(buf, vaddr, fb, clip);
+    src = buf;
+
+    for (y = clip->y1; y < clip->y2; y++) {
+        for (x = clip->x1; x < clip->x2; x += 3) {
+            val = st7586_lookup[*src++ >> 6] << 5;
+            val |= st7586_lookup[*src++ >> 6] << 2;
+            val |= st7586_lookup[*src++ >> 6] >> 1;
+            *dst++ = val;
+        }
+    }
+
+    kfree(buf);
+}
+
+static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
+               struct drm_clip_rect *clip)
+{
+    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;
+    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;
+    }
+
+    st7586_xrgb8888_to_gray332(dst, src, fb, clip);
+
+    if (import_attach)
+        ret = dma_buf_end_cpu_access(import_attach->dmabuf,
+                         DMA_FROM_DEVICE);
+
+    return ret;
+}
+
+static int st7586_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 tinydrm_device *tdev = fb->dev->dev_private;
+    struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
+    struct drm_clip_rect clip;
+    int start, end;
+    int ret = 0;
+
+    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;
+
+    tinydrm_merge_clips(&clip, clips, num_clips, flags, fb->width,
+                fb->height);
+
+    /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
+    clip.x1 = rounddown(clip.x1, 3);
+    clip.x2 = roundup(clip.x2, 3);
+
+ 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);
+
+    ret = st7586_buf_copy(mipi->tx_buf, fb, &clip);
+    if (ret)
+        goto out_unlock;
+
+    /* Pixels are packed 3 per byte */
+    start = clip.x1 / 3;
+    end = clip.x2 / 3;
+
+    mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,
+             (start >> 8) & 0xFF, start & 0xFF,
+             (end >> 8) & 0xFF, (end - 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,
+                   (u8 *)mipi->tx_buf,
+                   (end - start) * (clip.y2 - clip.y1));
+
+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 st7586_fb_funcs = {
+    .destroy    = drm_fb_cma_destroy,
+    .create_handle    = drm_fb_cma_create_handle,
+    .dirty        = st7586_fb_dirty,
+};
+
+void st7586_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;
+    struct device *dev = tdev->drm->dev;
+    int ret;
+    u8 addr_mode;
+
+    DRM_DEBUG_KMS("\n");
+
+    mipi_dbi_hw_reset(mipi);
+    ret = mipi_dbi_command(mipi, ST7586_AUTO_READ_CTRL, 0x9f);
+    if (ret) {
+        dev_err(dev, "Error sending command %d\n", ret);
+        return;
+    }
+
+    mipi_dbi_command(mipi, ST7586_OTP_RW_CTRL, 0x00);
+
+    msleep(10);
+
+    mipi_dbi_command(mipi, ST7586_OTP_READ);
+
+    msleep(20);
+
+    mipi_dbi_command(mipi, ST7586_OTP_CTRL_OUT);
+    mipi_dbi_command(mipi, MIPI_DCS_EXIT_SLEEP_MODE);
+    mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
+
+    msleep(50);
+
+    mipi_dbi_command(mipi, ST7586_SET_VOP_OFFSET, 0x00);
+    mipi_dbi_command(mipi, ST7586_SET_VOP, 0xe3, 0x00);
+    mipi_dbi_command(mipi, ST7586_SET_BIAS_SYSTEM, 0x02);
+    mipi_dbi_command(mipi, ST7586_SET_BOOST_LEVEL, 0x04);
+    mipi_dbi_command(mipi, ST7586_ENABLE_ANALOG, 0x1d);
+    mipi_dbi_command(mipi, ST7586_SET_NLINE_INV, 0x00);
+    mipi_dbi_command(mipi, ST7586_DISP_MODE_GRAY);
+    mipi_dbi_command(mipi, ST7586_ENABLE_DDRAM, 0x02);
+
+    switch (mipi->rotation) {
+    default:
+        addr_mode = 0x00;
+        break;
+    case 90:
+        addr_mode = ST7586_DISP_CTRL_MY;
+        break;
+    case 180:
+        addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
+        break;
+    case 270:
+        addr_mode = ST7586_DISP_CTRL_MX;
+        break;
+    }
+    mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
+
+    mipi_dbi_command(mipi, ST7586_SET_DISP_DUTY, 0x7f);
+    mipi_dbi_command(mipi, ST7586_SET_PART_DISP, 0xa0);
+ mipi_dbi_command(mipi, MIPI_DCS_SET_PARTIAL_AREA, 0x00, 0x00, 0x00, 0x77);
+    mipi_dbi_command(mipi, MIPI_DCS_EXIT_INVERT_MODE);
+
+    msleep(100);
+
+    mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_ON);
+
+    mipi->enabled = true;
+
+    if (fb)
+        fb->funcs->dirty(fb, NULL, 0, 0, NULL, 0);
+}
+
+static void st7586_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");
+
+    if (!mipi->enabled)
+        return;
+
+    mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
+    mipi->enabled = false;
+}
+
+static const u32 st7586_formats[] = {
+    DRM_FORMAT_XRGB8888,
+};
+
+static int st7586_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 + 2) / 3 * mode->hdisplay;
+    struct tinydrm_device *tdev = &mipi->tinydrm;
+    int ret;
+
+    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, &st7586_fb_funcs, driver);
+    if (ret)
+        return ret;
+
+    ret = tinydrm_display_pipe_init(tdev, pipe_funcs,
+                    DRM_MODE_CONNECTOR_VIRTUAL,
+                    st7586_formats,
+                    ARRAY_SIZE(st7586_formats),
+                    mode, rotation);
+    if (ret)
+        return ret;
+
+    tdev->drm->mode_config.preferred_depth = 32;
+    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;
+}
+
+static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
+    .enable        = st7586_pipe_enable,
+    .disable    = st7586_pipe_disable,
+    .update        = tinydrm_display_pipe_update,
+    .prepare_fb    = tinydrm_display_pipe_prepare_fb,
+};
+
+static const struct drm_display_mode st7586_mode = {
+    TINYDRM_MODE(178, 128, 37, 27),
+};
+
+DEFINE_DRM_GEM_CMA_FOPS(st7586_fops);
+
+static struct drm_driver st7586_driver = {
+    .driver_features    = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
+                  DRIVER_ATOMIC,
+    .fops            = &st7586_fops,
+    TINYDRM_GEM_DRIVER_OPS,
+    .lastclose        = tinydrm_lastclose,
+    .debugfs_init        = mipi_dbi_debugfs_init,
+    .name            = "st7586",
+    .desc            = "Sitronix ST7586",
+    .date            = "20170801",
+    .major            = 1,
+    .minor            = 0,
+};
+
+static const struct of_device_id st7586_of_match[] = {
+    { .compatible = "lego,ev3-lcd" },
+    {},
+};
+MODULE_DEVICE_TABLE(of, st7586_of_match);
+
+static const struct spi_device_id st7586_id[] = {
+    { "ev3-lcd", 0 },
+    { },
+};
+MODULE_DEVICE_TABLE(spi, st7586_id);
+
+static int st7586_probe(struct spi_device *spi)
+{
+    struct device *dev = &spi->dev;
+    struct tinydrm_device *tdev;
+    struct mipi_dbi *mipi;
+    struct gpio_desc *a0;
+    u32 rotation = 0;
+    int ret;
+
+    mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);
+    if (!mipi)
+        return -ENOMEM;
+
+    mipi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+    if (IS_ERR(mipi->reset)) {
+        dev_err(dev, "Failed to get gpio 'reset'\n");
+        return PTR_ERR(mipi->reset);
+    }
+
+    a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
+    if (IS_ERR(a0)) {
+        dev_err(dev, "Failed to get gpio 'a0'\n");
+        return PTR_ERR(a0);
+    }
+
+    device_property_read_u32(dev, "rotation", &rotation);
+
+    ret = mipi_dbi_spi_init(spi, mipi, a0);
+    if (ret)
+        return ret;
+
+    /* Cannot read from this controller via SPI */
+    mipi->read_commands = NULL;
+
+    /*
+ * we are using 8-bit data, so we are not actually swapping anything, + * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the + * right thing and not use 16-bit transfers (which results in swapped + * bytes on little-endian systems and causes out of order data to be
+     * sent to the display).
+     */
+    mipi->swap_bytes = true;
+
+ ret = st7586_init(&spi->dev, mipi, &st7586_pipe_funcs, &st7586_driver,
+              &st7586_mode, rotation);
+    if (ret)
+        return ret;
+
+    tdev = &mipi->tinydrm;
+
+    ret = devm_tinydrm_register(tdev);
+    if (ret)
+        return ret;
+
+    spi_set_drvdata(spi, mipi);
+
+    DRM_DEBUG_DRIVER("Initialized %s:%s @%uMHz on minor %d\n",
+             tdev->drm->driver->name, dev_name(dev),
+             spi->max_speed_hz / 1000000,
+             tdev->drm->primary->index);
+
+    return 0;
+}
+
+static void st7586_shutdown(struct spi_device *spi)
+{
+    struct mipi_dbi *mipi = spi_get_drvdata(spi);
+
+    tinydrm_shutdown(&mipi->tinydrm);
+}
+
+static struct spi_driver st7586_spi_driver = {
+    .driver = {
+        .name = "st7586",
+        .owner = THIS_MODULE,
+        .of_match_table = st7586_of_match,
+    },
+    .id_table = st7586_id,
+    .probe = st7586_probe,
+    .shutdown = st7586_shutdown,
+};
+module_spi_driver(st7586_spi_driver);
+
+MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
+MODULE_AUTHOR("David Lechner <david@xxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");

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