--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/clk.h>
+#include <linux/of_clk.h>
+#include <linux/platform_data/simplefb.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#include <drm/drm_atomic_state_helper.h>
+#include <drm/drm_connector.h>
+#include <drm/drm_damage_helper.h>
+#include <drm/drm_device.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_format_helper.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_gem_shmem_helper.h>
+#include <drm/drm_managed.h>
+#include <drm/drm_modeset_helper_vtables.h>
+#include <drm/drm_probe_helper.h>
+#include <drm/drm_simple_kms_helper.h>
+
+#define DRIVER_NAME    "simpledrm"
+#define DRIVER_DESC    "DRM driver for simple-framebuffer platform devices"
+#define DRIVER_DATE    "20200625"
+#define DRIVER_MAJOR   1
+#define DRIVER_MINOR   0
+
+/*
+ * Assume a monitor resolution of 96 dpi to
+ * get a somewhat reasonable screen size.
+ */
+#define RES_MM(d)      \
+       (((d) * 254ul) / (96ul * 10ul))
+
+#define SIMPLEDRM_MODE(hd, vd) \
+       DRM_SIMPLE_MODE(hd, vd, RES_MM(hd), RES_MM(vd))
+
+/*
+ * Helpers for simplefb
+ */
+
+static int
+simplefb_get_validated_int(struct drm_device *dev, const char *name,
+                          uint32_t value)
+{
+       if (value > INT_MAX) {
+               drm_err(dev, "simplefb: invalid framebuffer %s of %u\n",
+                       name, value);
+               return -EINVAL;
+       }
+       return (int)value;
+}
+
+static int
+simplefb_get_validated_int0(struct drm_device *dev, const char *name,
+                           uint32_t value)
+{
+       if (!value) {
+               drm_err(dev, "simplefb: invalid framebuffer %s of %u\n",
+                       name, value);
+               return -EINVAL;
+       }
+       return simplefb_get_validated_int(dev, name, value);
+}
+
+static const struct drm_format_info *
+simplefb_get_validated_format(struct drm_device *dev, const char *format_name)
+{
+       static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
+       const struct simplefb_format *fmt = formats;
+       const struct simplefb_format *end = fmt + ARRAY_SIZE(formats);
+
+       if (!format_name) {
+               drm_err(dev, "simplefb: missing framebuffer format\n");
+               return ERR_PTR(-EINVAL);
+       }
+
+       while (fmt < end) {
+               if (!strcmp(format_name, fmt->name))
+                       return drm_format_info(fmt->fourcc);
+               ++fmt;
+       }
+
+       drm_err(dev, "simplefb: unknown framebuffer format %s\n",
+               format_name);
+
+       return ERR_PTR(-EINVAL);
+}
+
+static int
+simplefb_get_width_pd(struct drm_device *dev,
+                     const struct simplefb_platform_data *pd)
+{
+       return simplefb_get_validated_int0(dev, "width", pd->width);
+}
+
+static int
+simplefb_get_height_pd(struct drm_device *dev,
+                      const struct simplefb_platform_data *pd)
+{
+       return simplefb_get_validated_int0(dev, "height", pd->height);
+}
+
+static int
+simplefb_get_stride_pd(struct drm_device *dev,
+                      const struct simplefb_platform_data *pd)
+{
+       return simplefb_get_validated_int(dev, "stride", pd->stride);
+}
+
+static const struct drm_format_info *
+simplefb_get_format_pd(struct drm_device *dev,
+                      const struct simplefb_platform_data *pd)
+{
+       return simplefb_get_validated_format(dev, pd->format);
+}
+
+static int
+simplefb_read_u32_of(struct drm_device *dev, struct device_node *of_node,
+                    const char *name, u32 *value)
+{
+       int ret = of_property_read_u32(of_node, name, value);
+
+       if (ret)
+               drm_err(dev, "simplefb: cannot parse framebuffer %s: error %d\n",
+                       name, ret);
+       return ret;
+}
+
+static int
+simplefb_read_string_of(struct drm_device *dev, struct device_node *of_node,
+                       const char *name, const char **value)
+{
+       int ret = of_property_read_string(of_node, name, value);
+
+       if (ret)
+               drm_err(dev, "simplefb: cannot parse framebuffer %s: error %d\n",
+                       name, ret);
+       return ret;
+}
+
+static int
+simplefb_get_width_of(struct drm_device *dev, struct device_node *of_node)
+{
+       u32 width;
+       int ret = simplefb_read_u32_of(dev, of_node, "width", &width);
+
+       if (ret)
+               return ret;
+       return simplefb_get_validated_int0(dev, "width", width);
+}
+
+static int
+simplefb_get_height_of(struct drm_device *dev, struct device_node *of_node)
+{
+       u32 height;
+       int ret = simplefb_read_u32_of(dev, of_node, "height", &height);
+
+       if (ret)
+               return ret;
+       return simplefb_get_validated_int0(dev, "height", height);
+}
+
+static int
+simplefb_get_stride_of(struct drm_device *dev, struct device_node *of_node)
+{
+       u32 stride;
+       int ret = simplefb_read_u32_of(dev, of_node, "stride", &stride);
+
+       if (ret)
+               return ret;
+       return simplefb_get_validated_int(dev, "stride", stride);
+}
+
+static const struct drm_format_info *
+simplefb_get_format_of(struct drm_device *dev, struct device_node *of_node)
+{
+       const char *format;
+       int ret = simplefb_read_string_of(dev, of_node, "format", &format);
+
+       if (ret)
+               return ERR_PTR(ret);
+       return simplefb_get_validated_format(dev, format);
+}
+
+/*
+ * Simple Framebuffer device
+ */
+
+struct simpledrm_device {
+       struct drm_device dev;
+       struct platform_device *pdev;
+
+       /* clocks */
+#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
+       unsigned int clk_count;
+       struct clk **clks;
+#endif
+       /* regulators */
+#if defined CONFIG_OF && defined CONFIG_REGULATOR
+       unsigned int regulator_count;
+       struct regulator **regulators;
+#endif
+
+       /* simplefb settings */
+       struct drm_display_mode mode;
+       const struct drm_format_info *format;
+       unsigned int pitch;
+
+       /* memory management */
+       struct resource *mem;
+       void __iomem *screen_base;
+
+       /* modesetting */
+       uint32_t formats[8];
+       size_t nformats;
+       struct drm_connector connector;
+       struct drm_simple_display_pipe pipe;
+};
+
+static struct simpledrm_device *simpledrm_device_of_dev(struct drm_device *dev)
+{
+       return container_of(dev, struct simpledrm_device, dev);
+}
+
+/*
+ * Hardware
+ */
+
+#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
+/*
+ * Clock handling code.
+ *
+ * Here we handle the clocks property of our "simple-framebuffer" dt node.
+ * This is necessary so that we can make sure that any clocks needed by
+ * the display engine that the bootloader set up for us (and for which it
+ * provided a simplefb dt node), stay up, for the life of the simplefb
+ * driver.
+ *
+ * When the driver unloads, we cleanly disable, and then release the clocks.
+ *
+ * We only complain about errors here, no action is taken as the most likely
+ * error can only happen due to a mismatch between the bootloader which set
+ * up simplefb, and the clock definitions in the device tree. Chances are
+ * that there are no adverse effects, and if there are, a clean teardown of
+ * the fb probe will not help us much either. So just complain and carry on,
+ * and hope that the user actually gets a working fb at the end of things.
+ */
+
+static void simpledrm_device_release_clocks(void *res)
+{
+       struct simpledrm_device *sdev = simpledrm_device_of_dev(res);
+       unsigned int i;
+
+       for (i = 0; i < sdev->clk_count; ++i) {
+               if (sdev->clks[i]) {
+                       clk_disable_unprepare(sdev->clks[i]);
+                       clk_put(sdev->clks[i]);
+               }
+       }
+}
+
+static int simpledrm_device_init_clocks(struct simpledrm_device *sdev)
+{
+       struct drm_device *dev = &sdev->dev;
+       struct platform_device *pdev = sdev->pdev;
+       struct device_node *of_node = pdev->dev.of_node;
+       struct clk *clock;
+       unsigned int i;
+       int ret;
+
+       if (dev_get_platdata(&pdev->dev) || !of_node)
+               return 0;
+
+       sdev->clk_count = of_clk_get_parent_count(of_node);
+       if (!sdev->clk_count)
+               return 0;
+
+       sdev->clks = drmm_kzalloc(dev, sdev->clk_count * sizeof(sdev->clks[0]),
+                                 GFP_KERNEL);
+       if (!sdev->clks)
+               return -ENOMEM;
+
+       for (i = 0; i < sdev->clk_count; ++i) {
+               clock = of_clk_get(of_node, i);
+               if (IS_ERR(clock)) {
+                       ret = PTR_ERR(clock);
+                       if (ret == -EPROBE_DEFER)
+                               goto err;
+                       drm_err(dev, "clock %u not found: %d\n", i, ret);
+                       continue;
+               }
+               ret = clk_prepare_enable(clock);
+               if (ret) {
+                       drm_err(dev, "failed to enable clock %u: %d\n",
+                               i, ret);
+                       clk_put(clock);
+               }
+               sdev->clks[i] = clock;
+       }
+
+       return devm_add_action_or_reset(&pdev->dev,
+                                       simpledrm_device_release_clocks,
+                                       sdev);
+
+err:
+       while (i) {
+               --i;
+               if (sdev->clks[i]) {
+                       clk_disable_unprepare(sdev->clks[i]);
+                       clk_put(sdev->clks[i]);
+               }
+       }
+       return ret;
+}
+#else
+static int simpledrm_device_init_clocks(struct simpledrm_device *sdev)
+{
+       return 0;
+}
+#endif
+
+#if defined CONFIG_OF && defined CONFIG_REGULATOR
+
+#define SUPPLY_SUFFIX "-supply"
+
+/*
+ * Regulator handling code.
+ *
+ * Here we handle the num-supplies and vin*-supply properties of our
+ * "simple-framebuffer" dt node. This is necessary so that we can make sure
+ * that any regulators needed by the display hardware that the bootloader
+ * set up for us (and for which it provided a simplefb dt node), stay up,
+ * for the life of the simplefb driver.
+ *
+ * When the driver unloads, we cleanly disable, and then release the
+ * regulators.
+ *
+ * We only complain about errors here, no action is taken as the most likely
+ * error can only happen due to a mismatch between the bootloader which set
+ * up simplefb, and the regulator definitions in the device tree. Chances are
+ * that there are no adverse effects, and if there are, a clean teardown of
+ * the fb probe will not help us much either. So just complain and carry on,
+ * and hope that the user actually gets a working fb at the end of things.
+ */
+
+static void simpledrm_device_release_regulators(void *res)
+{
+       struct simpledrm_device *sdev = simpledrm_device_of_dev(res);
+       unsigned int i;
+
+       for (i = 0; i < sdev->regulator_count; ++i) {
+               if (sdev->regulators[i]) {
+                       regulator_disable(sdev->regulators[i]);
+                       regulator_put(sdev->regulators[i]);
+               }
+       }
+}
+
+static int simpledrm_device_init_regulators(struct simpledrm_device *sdev)
+{
+       struct drm_device *dev = &sdev->dev;
+       struct platform_device *pdev = sdev->pdev;
+       struct device_node *of_node = pdev->dev.of_node;
+       struct property *prop;
+       struct regulator *regulator;
+       const char *p;
+       unsigned int count = 0, i = 0;
+       int ret;
+
+       if (dev_get_platdata(&pdev->dev) || !of_node)
+               return 0;
+
+       /* Count the number of regulator supplies */
+       for_each_property_of_node(of_node, prop) {
+               p = strstr(prop->name, SUPPLY_SUFFIX);
+               if (p && p != prop->name)
+                       ++count;
+       }
+
+       if (!count)
+               return 0;
+
+       sdev->regulators = drmm_kzalloc(dev,
+                                       count * sizeof(sdev->regulators[0]),
+                                       GFP_KERNEL);
+       if (!sdev->regulators)
+               return -ENOMEM;
+
+       for_each_property_of_node(of_node, prop) {
+               char name[32]; /* 32 is max size of property name */
+               size_t len;
+
+               p = strstr(prop->name, SUPPLY_SUFFIX);
+               if (!p || p == prop->name)
+                       continue;
+               len = strlen(prop->name) - strlen(SUPPLY_SUFFIX) + 1;
+               strscpy(name, prop->name, min(sizeof(name), len));
+
+               regulator = regulator_get_optional(&pdev->dev, name);
+               if (IS_ERR(regulator)) {
+                       ret = PTR_ERR(regulator);
+                       if (ret == -EPROBE_DEFER)
+                               goto err;
+                       drm_err(dev, "regulator %s not found: %d\n",
+                               name, ret);
+                       continue;
+               }
+
+               ret = regulator_enable(regulator);
+               if (ret) {
+                       drm_err(dev, "failed to enable regulator %u: %d\n",
+                               i, ret);
+                       regulator_put(regulator);
+               }
+
+               sdev->regulators[i++] = regulator;
+       }
+       sdev->regulator_count = i;
+
+       return devm_add_action_or_reset(&pdev->dev,
+                                       simpledrm_device_release_regulators,
+                                       sdev);
+
+err:
+       while (i) {
+               --i;
+               if (sdev->regulators[i]) {
+                       regulator_disable(sdev->regulators[i]);
+                       regulator_put(sdev->regulators[i]);
+               }
+       }
+       return ret;
+}
+#else
+static int simpledrm_device_init_regulators(struct simpledrm_device *sdev)
+{
+       return 0;
+}
+#endif
+
+/*
+ *  Simplefb settings
+ */
+
+static struct drm_display_mode simpledrm_mode(unsigned int width,
+                                             unsigned int height)
+{
+       struct drm_display_mode mode = { SIMPLEDRM_MODE(width, height) };
+
+       mode.clock = 60 /* Hz */ * mode.hdisplay * mode.vdisplay;
+       drm_mode_set_name(&mode);
+
+       return mode;
+}
+
+static int simpledrm_device_init_fb(struct simpledrm_device *sdev)
+{
+       int width, height, stride;
+       const struct drm_format_info *format;
+       struct drm_format_name_buf buf;
+       struct drm_device *dev = &sdev->dev;
+       struct platform_device *pdev = sdev->pdev;
+       const struct simplefb_platform_data *pd = dev_get_platdata(&pdev->dev);
+       struct device_node *of_node = pdev->dev.of_node;
+
+       if (pd) {
+               width = simplefb_get_width_pd(dev, pd);
+               if (width < 0)
+                       return width;
+               height = simplefb_get_height_pd(dev, pd);
+               if (height < 0)
+                       return height;
+               stride = simplefb_get_stride_pd(dev, pd);
+               if (stride < 0)
+                       return stride;
+               format = simplefb_get_format_pd(dev, pd);
+               if (IS_ERR(format))
+                       return PTR_ERR(format);
+       } else if (of_node) {
+               width = simplefb_get_width_of(dev, of_node);
+               if (width < 0)
+                       return width;
+               height = simplefb_get_height_of(dev, of_node);
+               if (height < 0)
+                       return height;
+               stride = simplefb_get_stride_of(dev, of_node);
+               if (stride < 0)
+                       return stride;
+               format = simplefb_get_format_of(dev, of_node);
+               if (IS_ERR(format))
+                       return PTR_ERR(format);
+       } else {
+               drm_err(dev, "no simplefb configuration found\n");
+               return -ENODEV;
+       }
+
+       sdev->mode = simpledrm_mode(width, height);
+       sdev->format = format;
+       sdev->pitch = stride;
+
+       drm_dbg_kms(dev, "display mode={" DRM_MODE_FMT "}\n",
+                   DRM_MODE_ARG(&sdev->mode));
+       drm_dbg_kms(dev,
+                   "framebuffer format=\"%s\", size=%dx%d, stride=%d byte\n",
+                   drm_get_format_name(format->format, &buf), width,
+                   height, stride);
+
+       return 0;
+}
+
+/*
+ * Memory management
+ */
+
+static int simpledrm_device_init_mm(struct simpledrm_device *sdev)
+{
+       struct platform_device *pdev = sdev->pdev;
+       struct resource *mem;
+       void __iomem *screen_base;
+
+       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!mem)
+               return -EINVAL;
+
+       screen_base = devm_ioremap_wc(&pdev->dev, mem->start,
+                                     resource_size(mem));
+       if (!screen_base)
+               return -ENOMEM;
+
+       sdev->mem = mem;
+       sdev->screen_base = screen_base;
+
+       return 0;
+}
+
+/*
+ * Modesetting
+ */
+
+/*
+ * Support all formats of simplefb and maybe more; in order
+ * of preference. The display's update function will do any
+ * conversion necessary.
+ *
+ * TODO: Add blit helpers for remaining formats and uncomment
+ *       constants.
+ */
+static const uint32_t simpledrm_default_formats[] = {
+       DRM_FORMAT_XRGB8888,
+       DRM_FORMAT_ARGB8888,
+       DRM_FORMAT_RGB565,
+       //DRM_FORMAT_XRGB1555,
+       //DRM_FORMAT_ARGB1555,
+       DRM_FORMAT_RGB888,
+       //DRM_FORMAT_XRGB2101010,
+       //DRM_FORMAT_ARGB2101010,
+};
+
+static const uint64_t simpledrm_format_modifiers[] = {
+       DRM_FORMAT_MOD_LINEAR,
+       DRM_FORMAT_MOD_INVALID
+};
+
+static int simpledrm_connector_helper_get_modes(struct drm_connector *connector)
+{
+       struct simpledrm_device *sdev = simpledrm_device_of_dev(connector->dev);
+       struct drm_display_mode *mode;
+
+       mode = drm_mode_duplicate(connector->dev, &sdev->mode);
+       if (!mode)
+               return 0;
+
+       if (mode->name[0] == '\0')
+               drm_mode_set_name(mode);
+
+       mode->type |= DRM_MODE_TYPE_PREFERRED;
+       drm_mode_probed_add(connector, mode);
+
+       if (mode->width_mm)
+               connector->display_info.width_mm = mode->width_mm;
+       if (mode->height_mm)
+               connector->display_info.height_mm = mode->height_mm;
+
+       return 1;
+}
+
+static const struct drm_connector_helper_funcs simpledrm_connector_helper_funcs = {
+       .get_modes = simpledrm_connector_helper_get_modes,
+};
+
+static const struct drm_connector_funcs simpledrm_connector_funcs = {
+       .reset = drm_atomic_helper_connector_reset,
+       .fill_modes = drm_helper_probe_single_connector_modes,
+       .destroy = drm_connector_cleanup,
+       .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+       .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static int
+simpledrm_simple_display_pipe_mode_valid(struct drm_simple_display_pipe *pipe,
+                                   const struct drm_display_mode *mode)
+{
+       struct simpledrm_device *sdev = simpledrm_device_of_dev(pipe->crtc.dev);
+
+       if (mode->hdisplay != sdev->mode.hdisplay &&
+           mode->vdisplay != sdev->mode.vdisplay)
+               return MODE_ONE_SIZE;
+       else if (mode->hdisplay != sdev->mode.hdisplay)
+               return MODE_ONE_WIDTH;
+       else if (mode->vdisplay != sdev->mode.vdisplay)
+               return MODE_ONE_HEIGHT;
+
+       return MODE_OK;
+}
+
+static void
+simpledrm_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe,
+                                    struct drm_crtc_state *crtc_state,
+                                    struct drm_plane_state *plane_state)
+{
+       struct simpledrm_device *sdev = simpledrm_device_of_dev(pipe->crtc.dev);
+       struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
+       struct drm_framebuffer *fb = plane_state->fb;
+       void *vmap = shadow_plane_state->map[0].vaddr; /* TODO: Use mapping abstraction properly */
+
+       if (!fb)
+               return;
+
+       drm_fb_blit_dstclip(sdev->screen_base, sdev->pitch,
+                           sdev->format->format, vmap, fb);
+}
+
+static void
+simpledrm_simple_display_pipe_disable(struct drm_simple_display_pipe *pipe)
+{
+       struct simpledrm_device *sdev = simpledrm_device_of_dev(pipe->crtc.dev);
+       struct drm_device *dev = &sdev->dev;
+       int idx;
+
+       if (!drm_dev_enter(dev, &idx))
+               return;
+
+       /* Clear screen to black if disabled */
+       memset_io(sdev->screen_base, 0, sdev->pitch * sdev->mode.vdisplay);
+
+       drm_dev_exit(idx);
+}
+
+static void
+simpledrm_simple_display_pipe_update(struct drm_simple_display_pipe *pipe,
+                                    struct drm_plane_state *old_plane_state)
+{
+       struct simpledrm_device *sdev = simpledrm_device_of_dev(pipe->crtc.dev);
+       struct drm_plane_state *plane_state = pipe->plane.state;
+       struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
+       void *vmap = shadow_plane_state->map[0].vaddr; /* TODO: Use mapping abstraction properly */
+       struct drm_framebuffer *fb = plane_state->fb;
+       struct drm_rect clip;
+
+       if (!fb)
+               return;
+
+       if (!drm_atomic_helper_damage_merged(old_plane_state, plane_state, &clip))
+               return;
+
+       drm_fb_blit_rect_dstclip(sdev->screen_base, sdev->pitch,
+                                sdev->format->format, vmap, fb, &clip);
+}
+
+static const struct drm_simple_display_pipe_funcs
+simpledrm_simple_display_pipe_funcs = {
+       .mode_valid = simpledrm_simple_display_pipe_mode_valid,
+       .enable = simpledrm_simple_display_pipe_enable,
+       .disable = simpledrm_simple_display_pipe_disable,
+       .update = simpledrm_simple_display_pipe_update,
+       DRM_GEM_SIMPLE_DISPLAY_PIPE_SHADOW_PLANE_FUNCS,
+};
+
+static const struct drm_mode_config_funcs simpledrm_mode_config_funcs = {
+       .fb_create = drm_gem_fb_create_with_dirty,
+       .atomic_check = drm_atomic_helper_check,
+       .atomic_commit = drm_atomic_helper_commit,
+};
+
+static const uint32_t *simpledrm_device_formats(struct simpledrm_device *sdev,
+                                               size_t *nformats_out)
+{
+       struct drm_device *dev = &sdev->dev;
+       size_t i;
+
+       if (sdev->nformats)
+               goto out; /* don't rebuild list on recurring calls */
+
+       /* native format goes first */
+       sdev->formats[0] = sdev->format->format;
+       sdev->nformats = 1;
+
+       /* default formats go second */
+       for (i = 0; i < ARRAY_SIZE(simpledrm_default_formats); ++i) {
+               if (simpledrm_default_formats[i] == sdev->format->format)
+                       continue; /* native format already went first */
+               sdev->formats[sdev->nformats] = simpledrm_default_formats[i];
+               sdev->nformats++;
+       }
+
+       /*
+        * TODO: The simpledrm driver converts framebuffers to the native
+        * format when copying them to device memory. If there are more
+        * formats listed than supported by the driver, the native format
+        * is not supported by the conversion helpers. Therefore *only*
+        * support the native format and add a conversion helper ASAP.
+        */
+       if (drm_WARN_ONCE(dev, i != sdev->nformats,
+                         "format conversion helpers required for %p4cc",
+                         &sdev->format->format)) {
+               sdev->nformats = 1;
+       }
+
+out:
+       *nformats_out = sdev->nformats;
+       return sdev->formats;
+}
+
+static int simpledrm_device_init_modeset(struct simpledrm_device *sdev)
+{
+       struct drm_device *dev = &sdev->dev;
+       struct drm_display_mode *mode = &sdev->mode;
+       struct drm_connector *connector = &sdev->connector;
+       struct drm_simple_display_pipe *pipe = &sdev->pipe;
+       const uint32_t *formats;
+       size_t nformats;
+       int ret;
+
+       ret = drmm_mode_config_init(dev);
+       if (ret)
+               return ret;
+
+       dev->mode_config.min_width = mode->hdisplay;
+       dev->mode_config.max_width = mode->hdisplay;
+       dev->mode_config.min_height = mode->vdisplay;
+       dev->mode_config.max_height = mode->vdisplay;
+       dev->mode_config.prefer_shadow_fbdev = true;
+       dev->mode_config.preferred_depth = sdev->format->cpp[0] * 8;
+       dev->mode_config.funcs = &simpledrm_mode_config_funcs;
+
+       ret = drm_connector_init(dev, connector, &simpledrm_connector_funcs,
+                                DRM_MODE_CONNECTOR_Unknown);
+       if (ret)
+               return ret;
+       drm_connector_helper_add(connector, &simpledrm_connector_helper_funcs);
+
+       formats = simpledrm_device_formats(sdev, &nformats);
+
+       ret = drm_simple_display_pipe_init(dev, pipe, &simpledrm_simple_display_pipe_funcs,
+                                          formats, nformats, simpledrm_format_modifiers,
+                                          connector);
+       if (ret)
+               return ret;
+
+       drm_mode_config_reset(dev);
+
+       return 0;
+}
+
+/*
+ * Init / Cleanup
+ */
+
+static struct simpledrm_device *
+simpledrm_device_create(struct drm_driver *drv, struct platform_device *pdev)
+{
+       struct simpledrm_device *sdev;
+       int ret;
+
+       sdev = devm_drm_dev_alloc(&pdev->dev, drv, struct simpledrm_device,
+                                 dev);
+       if (IS_ERR(sdev))
+               return ERR_CAST(sdev);
+       sdev->pdev = pdev;
+       platform_set_drvdata(pdev, sdev);
+
+       ret = simpledrm_device_init_clocks(sdev);
+       if (ret)
+               return ERR_PTR(ret);
+       ret = simpledrm_device_init_regulators(sdev);
+       if (ret)
+               return ERR_PTR(ret);
+       ret = simpledrm_device_init_fb(sdev);
+       if (ret)
+               return ERR_PTR(ret);
+       ret = simpledrm_device_init_mm(sdev);
+       if (ret)
+               return ERR_PTR(ret);
+       ret = simpledrm_device_init_modeset(sdev);
+       if (ret)
+               return ERR_PTR(ret);
+
+       return sdev;
+}
+
+/*
+ * DRM driver
+ */
+
+DEFINE_DRM_GEM_FOPS(simpledrm_fops);
+
+static struct drm_driver simpledrm_driver = {
+       DRM_GEM_SHMEM_DRIVER_OPS,
+       .name                   = DRIVER_NAME,
+       .desc                   = DRIVER_DESC,
+       .date                   = DRIVER_DATE,
+       .major                  = DRIVER_MAJOR,
+       .minor                  = DRIVER_MINOR,
+       .driver_features        = DRIVER_ATOMIC | DRIVER_GEM | DRIVER_MODESET,
+       .fops                   = &simpledrm_fops,
+};
+
+/*
+ * Platform driver
+ */
+
+static int simpledrm_probe(struct platform_device *pdev)
+{
+       struct simpledrm_device *sdev;
+       struct drm_device *dev;
+       int ret;
+
+       sdev = simpledrm_device_create(&simpledrm_driver, pdev);
+       if (IS_ERR(sdev))
+               return PTR_ERR(sdev);
+       dev = &sdev->dev;
+
+       ret = drm_dev_register(dev, 0);
+       if (ret)
+               return ret;
+
+       drm_fbdev_generic_setup(dev, 0);
+
+       return 0;
+}
+
+static int simpledrm_remove(struct platform_device *pdev)
+{
+       struct simpledrm_device *sdev = platform_get_drvdata(pdev);
+       struct drm_device *dev = &sdev->dev;
+
+       drm_dev_unregister(dev);
+
+       return 0;
+}
+
+static const struct of_device_id simpledrm_of_match_table[] = {
+       { .compatible = "simple-framebuffer", },
+       { },
+};
+MODULE_DEVICE_TABLE(of, simpledrm_of_match_table);
+
+static struct platform_driver simpledrm_platform_driver = {
+       .driver = {
+               .name = "simple-framebuffer", /* connect to sysfb */
+               .of_match_table = simpledrm_of_match_table,
+       },
+       .probe = simpledrm_probe,
+       .remove = simpledrm_remove,
+};
+
+module_platform_driver(simpledrm_platform_driver);
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL v2");