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 <da...@lechnology.com>
---
 MAINTAINERS                      |   6 +
 drivers/gpu/drm/tinydrm/Kconfig  |  10 +
 drivers/gpu/drm/tinydrm/Makefile |   1 +
 drivers/gpu/drm/tinydrm/st7586.c | 466 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 483 insertions(+)
 create mode 100644 drivers/gpu/drm/tinydrm/st7586.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a1e772e..9643f95 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4365,6 +4365,12 @@ S:       Maintained
 F:     drivers/gpu/drm/tinydrm/repaper.c
 F:     Documentation/devicetree/bindings/display/repaper.txt
 
+DRM DRIVER FOR SITRONIX ST7586 PANELS
+M:     David Lechner <da...@lechnology.com>
+S:     Maintained
+F:     drivers/gpu/drm/tinydrm/st7586.c
+F:     Documentation/devicetree/bindings/display/st7586.txt
+
 DRM DRIVER FOR RAGE 128 VIDEO CARDS
 S:     Orphan / Obsolete
 F:     drivers/gpu/drm/r128/
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..11e226d
--- /dev/null
+++ b/drivers/gpu/drm/tinydrm/st7586.c
@@ -0,0 +1,466 @@
+/*
+ * DRM driver for Sitronix ST7586 panels
+ *
+ * Copyright 2017 David Lechner <da...@lechnology.com>
+ *
+ * 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/regulator/consumer.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)
+
+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;
+
+       /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
+       clip->x1 = clip->x1 / 3 * 3;
+       clip->x2 = (clip->x2 + 2) / 3 * 3;
+
+       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 = *src++ & 0xc0;
+                       if (val & 0xc0)
+                               val |= 0x20;
+                       val |= (*src++ & 0xc0) >> 3;
+                       if (val & 0x18)
+                               val |= 0x04;
+                       val |= *src++ >> 6;
+                       *dst++ = ~val;
+               }
+       }
+
+       /* now adjust the clip so it applies to dst */
+       clip->x1 /= 3;
+       clip->x2 /= 3;
+
+       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;
+       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_XRGB8888:
+               st7586_xrgb8888_to_gray332(dst, src, fb, clip);
+               break;
+       default:
+               dev_err_once(fb->dev->dev, "Format is not supported: %s\n",
+                            drm_get_format_name(fb->format->format,
+                                                &format_name));
+               ret = -EINVAL;
+               break;
+       }
+
+       if (import_attach)
+               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 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);
+
+       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;
+
+       /* NB: st7586_buf_copy() modifies clip */
+
+       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,
+                                  (u8 *)mipi->tx_buf,
+                                  (clip.x2 - clip.x1) * (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");
+
+       ret = regulator_enable(mipi->regulator);
+       if (ret) {
+               dev_err(dev, "Failed to enable regulator %d\n", ret);
+               return;
+       }
+
+       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);
+               regulator_disable(mipi->regulator);
+               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);
+
+       tinydrm_enable_backlight(mipi->backlight);
+}
+
+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->enabled = false;
+       tinydrm_disable_backlight(mipi->backlight);
+       mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
+       regulator_disable(mipi->regulator);
+}
+
+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 *dc;
+       u32 rotation = 0;
+       int ret;
+
+       mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);
+       if (!mipi)
+               return -ENOMEM;
+
+       mipi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+       if (IS_ERR(mipi->reset)) {
+               dev_err(dev, "Failed to get gpio 'reset'\n");
+               return PTR_ERR(mipi->reset);
+       }
+
+       dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW);
+       if (IS_ERR(dc)) {
+               dev_err(dev, "Failed to get gpio 'dc'\n");
+               return PTR_ERR(dc);
+       }
+
+       mipi->regulator = devm_regulator_get(dev, "power");
+       if (IS_ERR(mipi->regulator))
+               return PTR_ERR(mipi->regulator);
+
+       mipi->backlight = tinydrm_of_find_backlight(dev);
+       if (IS_ERR(mipi->backlight))
+               return PTR_ERR(mipi->backlight);
+
+       device_property_read_u32(dev, "rotation", &rotation);
+
+       ret = mipi_dbi_spi_init(spi, mipi, dc);
+       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 int __maybe_unused st7586_pm_suspend(struct device *dev)
+{
+       struct mipi_dbi *mipi = dev_get_drvdata(dev);
+
+       return tinydrm_suspend(&mipi->tinydrm);
+}
+
+static int __maybe_unused st7586_pm_resume(struct device *dev)
+{
+       struct mipi_dbi *mipi = dev_get_drvdata(dev);
+
+       return tinydrm_resume(&mipi->tinydrm);
+}
+
+static const struct dev_pm_ops st7586_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(st7586_pm_suspend, st7586_pm_resume)
+};
+
+static struct spi_driver st7586_spi_driver = {
+       .driver = {
+               .name = "st7586",
+               .owner = THIS_MODULE,
+               .of_match_table = st7586_of_match,
+               .pm = &st7586_pm_ops,
+       },
+       .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 <da...@lechnology.com>");
+MODULE_LICENSE("GPL");
-- 
2.7.4

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