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[211.23.39.77]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-748900822b7sm10147934b3a.101.2025.06.17.20.38.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 17 Jun 2025 20:38:36 -0700 (PDT) From: LiangCheng Wang To: cip-dev@lists.cip-project.org Cc: drm@lists.freedesktop.org, devicetree@vger.kernel.org, noralf@tronnes.org, robh+dt@kernel.org, krzk@kernel.org, zaq14760@gmail.com, onlywig@gmail.com Subject: [PATCH 2/3] drm: tiny: Add support for PIXPAPER e-ink panel Date: Wed, 18 Jun 2025 11:37:30 +0800 Message-Id: <20250618033731.171812-3-zaq14760@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250618033731.171812-1-zaq14760@gmail.com> References: <20250618033731.171812-1-zaq14760@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit List-Id: X-Webhook-Received: from li982-79.members.linode.com [45.33.32.79] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Wed, 18 Jun 2025 09:13:55 -0000 X-Groupsio-URL: https://lists.cip-project.org/g/cip-dev/message/19125 Introduce a DRM driver for the PIXPAPER e-ink display panel, which is controlled via SPI. The driver supports a 122x250 resolution display with XRGB8888 format, using the DRM simple KMS helper framework. Signed-off-by: LiangCheng Wang --- MAINTAINERS | 6 + drivers/gpu/drm/tiny/Kconfig | 11 + drivers/gpu/drm/tiny/Makefile | 1 + drivers/gpu/drm/tiny/pixpaper.c | 716 ++++++++++++++++++++++++++++++++ 4 files changed, 734 insertions(+) create mode 100644 drivers/gpu/drm/tiny/pixpaper.c diff --git a/MAINTAINERS b/MAINTAINERS index 66c628761..aac32556a 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -5534,6 +5534,12 @@ S: Orphan / Obsolete F: drivers/gpu/drm/i810/ F: include/uapi/drm/i810_drm.h +DRM DRIVER FOR PIXPAPER E-INK PANEL +M: LiangCheng Wang +S: Maintained +F: Documentation/devicetree/bindings/display/mayqueen,pixpaper.yaml +F: drivers/gpu/drm/tiny/pixpaper.c + DRM DRIVER FOR LVDS PANELS M: Laurent Pinchart L: dri-devel@lists.freedesktop.org diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig index 2b6414f0f..922753489 100644 --- a/drivers/gpu/drm/tiny/Kconfig +++ b/drivers/gpu/drm/tiny/Kconfig @@ -131,3 +131,14 @@ config TINYDRM_ST7735R * Okaya RH128128T 1.44" 128x128 TFT If M is selected the module will be called st7735r. + +config DRM_PIXPAPER + tristate "DRM support for PIXPAPER display panels" + depends on DRM && SPI + select DRM_KMS_HELPER + select DRM_KMS_CMA_HELPER + help + DRM driver for the following PIXPAPER panels + + If M is selected the module will be called pixpaper . + diff --git a/drivers/gpu/drm/tiny/Makefile b/drivers/gpu/drm/tiny/Makefile index 6ae4e9e5a..4b9e473ba 100644 --- a/drivers/gpu/drm/tiny/Makefile +++ b/drivers/gpu/drm/tiny/Makefile @@ -10,3 +10,4 @@ obj-$(CONFIG_TINYDRM_MI0283QT) += mi0283qt.o obj-$(CONFIG_TINYDRM_REPAPER) += repaper.o obj-$(CONFIG_TINYDRM_ST7586) += st7586.o obj-$(CONFIG_TINYDRM_ST7735R) += st7735r.o +obj-$(CONFIG_DRM_PIXPAPER) += pixpaper.o diff --git a/drivers/gpu/drm/tiny/pixpaper.c b/drivers/gpu/drm/tiny/pixpaper.c new file mode 100644 index 000000000..f6081cf96 --- /dev/null +++ b/drivers/gpu/drm/tiny/pixpaper.c @@ -0,0 +1,716 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * DRM driver for PIXPAPER e-ink panel + * + * Author: LC Wang , + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define PIXPAPER_WIDTH 122 +#define PIXPAPER_HEIGHT 250 + +#define PANEL_BUFFER_WIDTH 128 +#define PANEL_BUFFER_TWO_BYTES_PER_ROW (PANEL_BUFFER_WIDTH / 4) + +#define PIXPAPER_SPI_SPEED_DEFAULT 1000000 + +#define PIXPAPER_CMD_PANEL_SETTING 0x00 +#define PIXPAPER_CMD_POWER_SETTING 0x01 +#define PIXPAPER_CMD_POWER_OFF 0x02 +#define PIXPAPER_CMD_POWER_OFF_SEQUENCE 0x03 +#define PIXPAPER_CMD_POWER_ON 0x04 +#define PIXPAPER_CMD_BOOSTER_SOFT_START 0x06 +#define PIXPAPER_CMD_DEEP_SLEEP 0x07 +#define PIXPAPER_CMD_DATA_START_TRANSMISSION 0x10 +#define PIXPAPER_CMD_DISPLAY_REFRESH 0x12 +#define PIXPAPER_CMD_PLL_CONTROL 0x30 +#define PIXPAPER_CMD_TEMP_SENSOR_CALIB 0x41 +#define PIXPAPER_CMD_UNKNOWN_4D 0x4D +#define PIXPAPER_CMD_VCOM_INTERVAL 0x50 +#define PIXPAPER_CMD_TCON_SETTING 0x60 +#define PIXPAPER_CMD_RESOLUTION_SETTING 0x61 +#define PIXPAPER_CMD_GATE_SOURCE_START 0x65 +#define PIXPAPER_CMD_UNKNOWN_B4 0xB4 +#define PIXPAPER_CMD_UNKNOWN_B5 0xB5 +#define PIXPAPER_CMD_CASCADE_SETTING 0xE0 +#define PIXPAPER_CMD_POWER_SAVING 0xE3 +#define PIXPAPER_CMD_AUTO_MEASURE_VCOM 0xE7 +#define PIXPAPER_CMD_UNKNOWN_E9 0xE9 + +struct pixpaper_panel { + struct drm_device drm; + struct drm_simple_display_pipe pipe; + struct drm_connector connector; + struct spi_device *spi; + struct gpio_desc *reset; + struct gpio_desc *busy; + struct gpio_desc *dc; + struct mutex spi_lock; + struct mutex update_lock; + bool init_completed_successfully; +}; + +static const struct drm_display_mode pixpaper_mode = { + DRM_SIMPLE_MODE(PIXPAPER_WIDTH, PIXPAPER_HEIGHT, 30, 47), +}; + +static const uint32_t pixpaper_formats[] = { + DRM_FORMAT_XRGB8888, +}; + +static void pixpaper_wait_busy(struct pixpaper_panel *panel) +{ + unsigned int delay_us = 1000; + + usleep_range(delay_us, delay_us + 500); + while (true) + if (gpiod_get_value_cansleep(panel->busy) == 1) + break; +} + +static int pixpaper_spi_sync(struct spi_device *spi, struct spi_message *msg) +{ + int ret; + + ret = spi_sync(spi, msg); + if (ret < 0) + dev_err(&spi->dev, "SPI sync failed: %d\n", ret); + + return ret; +} + +static int pixpaper_send_cmd(struct pixpaper_panel *panel, u8 cmd) +{ + struct spi_transfer xfer = { + .tx_buf = &cmd, + .len = 1, + }; + struct spi_message msg; + int ret; + + spi_message_init(&msg); + spi_message_add_tail(&xfer, &msg); + + mutex_lock(&panel->spi_lock); + gpiod_set_value_cansleep(panel->dc, 0); + usleep_range(1, 5); + ret = pixpaper_spi_sync(panel->spi, &msg); + mutex_unlock(&panel->spi_lock); + + return ret; +} + +static int pixpaper_send_data(struct pixpaper_panel *panel, u8 data) +{ + struct spi_transfer xfer = { + .tx_buf = &data, + .len = 1, + }; + struct spi_message msg; + int ret; + + spi_message_init(&msg); + spi_message_add_tail(&xfer, &msg); + + mutex_lock(&panel->spi_lock); + gpiod_set_value_cansleep(panel->dc, 1); + usleep_range(1, 5); + ret = pixpaper_spi_sync(panel->spi, &msg); + mutex_unlock(&panel->spi_lock); + + return ret; +} + +static int pixpaper_panel_hw_init(struct pixpaper_panel *panel) +{ + struct device *dev = &panel->spi->dev; + int ret = 0; + + dev_info(dev, "%s: Starting hardware initialization\n", __func__); + + gpiod_set_value_cansleep(panel->reset, 0); + msleep(50); + gpiod_set_value_cansleep(panel->reset, 1); + msleep(50); + + pixpaper_wait_busy(panel); + dev_info(dev, "Hardware reset complete, panel idle.\n"); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_4D); + ret |= pixpaper_send_data(panel, 0x78); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_PANEL_SETTING); + ret |= pixpaper_send_data(panel, 0x0F); + ret |= pixpaper_send_data(panel, 0x09); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_SETTING); + ret |= pixpaper_send_data(panel, 0x07); + ret |= pixpaper_send_data(panel, 0x00); + ret |= pixpaper_send_data(panel, 0x22); + ret |= pixpaper_send_data(panel, 0x78); + ret |= pixpaper_send_data(panel, 0x0A); + ret |= pixpaper_send_data(panel, 0x22); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_OFF_SEQUENCE); + ret |= pixpaper_send_data(panel, 0x10); + ret |= pixpaper_send_data(panel, 0x54); + ret |= pixpaper_send_data(panel, 0x44); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_BOOSTER_SOFT_START); + ret |= pixpaper_send_data(panel, 0x0F); + ret |= pixpaper_send_data(panel, 0x0A); + ret |= pixpaper_send_data(panel, 0x2F); + ret |= pixpaper_send_data(panel, 0x25); + ret |= pixpaper_send_data(panel, 0x22); + ret |= pixpaper_send_data(panel, 0x2E); + ret |= pixpaper_send_data(panel, 0x21); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_PLL_CONTROL); + ret |= pixpaper_send_data(panel, 0x02); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_TEMP_SENSOR_CALIB); + ret |= pixpaper_send_data(panel, 0x00); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_VCOM_INTERVAL); + ret |= pixpaper_send_data(panel, 0x37); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_TCON_SETTING); + ret |= pixpaper_send_data(panel, 0x02); + ret |= pixpaper_send_data(panel, 0x02); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_RESOLUTION_SETTING); + ret |= pixpaper_send_data(panel, 0x00); + ret |= pixpaper_send_data(panel, 0x80); + ret |= pixpaper_send_data(panel, 0x00); + ret |= pixpaper_send_data(panel, 0xFA); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_GATE_SOURCE_START); + ret |= pixpaper_send_data(panel, 0x00); + ret |= pixpaper_send_data(panel, 0x00); + ret |= pixpaper_send_data(panel, 0x00); + ret |= pixpaper_send_data(panel, 0x00); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_AUTO_MEASURE_VCOM); + ret |= pixpaper_send_data(panel, 0x1C); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_SAVING); + ret |= pixpaper_send_data(panel, 0x22); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_CASCADE_SETTING); + ret |= pixpaper_send_data(panel, 0x00); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_B4); + ret |= pixpaper_send_data(panel, 0xD0); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_B5); + ret |= pixpaper_send_data(panel, 0x03); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + ret |= pixpaper_send_cmd(panel, PIXPAPER_CMD_UNKNOWN_E9); + ret |= pixpaper_send_data(panel, 0x01); + if (ret) + goto init_fail; + pixpaper_wait_busy(panel); + + dev_info(dev, "%s: Hardware initialization successful\n", __func__); + panel->init_completed_successfully = true; + return 0; + +init_fail: + dev_err(dev, "%s: Hardware initialization failed (err=%d)\n", __func__, ret); + panel->init_completed_successfully = false; + return ret; +} + +static void pixpaper_pipe_enable(struct drm_simple_display_pipe *pipe, + struct drm_crtc_state *crtc_state, + struct drm_plane_state *plane_state) +{ + struct pixpaper_panel *panel = container_of(pipe, struct pixpaper_panel, pipe); + struct drm_device *drm = &panel->drm; + int ret; + + dev_info(drm->dev, "%s: Enabling pipe\n", __func__); + + ret = pixpaper_panel_hw_init(panel); + if (ret) { + dev_err(drm->dev, "Panel HW Init failed during enable: %d\n", ret); + return; + } + + dev_info(drm->dev, "Sending Power ON (PON)\n"); + ret = pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_ON); + if (ret) { + dev_err(drm->dev, "Failed to send PON command: %d\n", ret); + return; + } + + usleep_range(10000, 11000); + + pixpaper_wait_busy(panel); + + dev_info(drm->dev, "Panel enabled and powered on\n"); +} + +static void pixpaper_pipe_disable(struct drm_simple_display_pipe *pipe) +{ + struct pixpaper_panel *panel = container_of(pipe, struct pixpaper_panel, pipe); + struct drm_device *drm = &panel->drm; + int ret; + + dev_dbg(drm->dev, "%s: Disabling pipe\n", __func__); + + ret = pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_OFF); + if (!ret) { + usleep_range(10000, 11000); + pixpaper_wait_busy(panel); + } else { + dev_warn(drm->dev, "Failed to send POF command: %d\n", ret); + } + dev_info(drm->dev, "Panel disabled\n"); +} + +static u8 pack_pixels_to_byte(u32 *src_pixels, int i, int j, struct drm_framebuffer *fb) +{ + u8 packed_byte = 0; + int k; + + for (k = 0; k < 4; k++) { + int current_pixel_x = j * 4 + k; + u8 two_bit_val; + + if (current_pixel_x < PIXPAPER_WIDTH) { + u32 pixel_offset = (i * (fb->pitches[0] / 4)) + current_pixel_x; + u32 pixel = src_pixels[pixel_offset]; + u32 r = (pixel >> 16) & 0xFF; + u32 g = (pixel >> 8) & 0xFF; + u32 b = pixel & 0xFF; + u32 gray_val = (r * 299 + g * 587 + b * 114 + 500) / 1000; + + if (gray_val < 64) + two_bit_val = 0b00; + else if (gray_val < 128) + two_bit_val = 0b01; + else if (gray_val < 192) + two_bit_val = 0b10; + else + two_bit_val = 0b11; + } else { + two_bit_val = 0b11; + } + + packed_byte |= two_bit_val << ((3 - k) * 2); + } + + return packed_byte; +} + +static void pixpaper_pipe_update(struct drm_simple_display_pipe *pipe, + struct drm_plane_state *old_plane_state) +{ + struct pixpaper_panel *panel = container_of(pipe, struct pixpaper_panel, pipe); + struct drm_device *drm = &panel->drm; + struct drm_plane_state *plane_state = pipe->plane.state; + struct drm_framebuffer *fb = plane_state->fb; + struct drm_gem_object *gem_obj; + struct dma_buf *dmabuf = NULL; + void *vaddr = NULL; + int i, j, ret = 0; + u32 *src_pixels = NULL; + + if (!panel->init_completed_successfully) { + dev_err(drm->dev, "CRITICAL: pipe_update called BEFORE init completed successfully!\n"); + return; + } + + dev_info(drm->dev, "Starting frame update (phys=%dx%d, buf_w=%d)\n", + PIXPAPER_WIDTH, PIXPAPER_HEIGHT, PANEL_BUFFER_WIDTH); + + if (mutex_lock_interruptible(&panel->update_lock)) { + dev_warn(drm->dev, "Frame update interrupted while waiting for lock\n"); + return; + } + + if (!fb || !plane_state->visible) { + dev_dbg(drm->dev, "No framebuffer or plane not visible, skipping update\n"); + mutex_unlock(&panel->update_lock); + return; + } + + gem_obj = drm_gem_fb_get_obj(fb, 0); + if (!gem_obj) { + dev_err(drm->dev, "Framebuffer has no backing GEM object\n"); + mutex_unlock(&panel->update_lock); + return; + } + + dmabuf = drm_gem_prime_export(gem_obj, O_RDONLY); + if (IS_ERR(dmabuf)) { + dev_err(drm->dev, "Failed to export GEM object to dma-buf: %ld\n", PTR_ERR(dmabuf)); + mutex_unlock(&panel->update_lock); + return; + } + + vaddr = dma_buf_vmap(dmabuf); + if (IS_ERR_OR_NULL(vaddr)) { + dev_err(drm->dev, "Failed to vmap dma-buf: %ld\n", + vaddr ? PTR_ERR(vaddr) : -ENOMEM); + dma_buf_put(dmabuf); + mutex_unlock(&panel->update_lock); + return; + } + src_pixels = (u32 *)vaddr; + + dev_info(drm->dev, "Sending DTM command\n"); + ret = pixpaper_send_cmd(panel, PIXPAPER_CMD_DATA_START_TRANSMISSION); + if (ret) + goto update_cleanup; + + usleep_range(10000, 11000); + pixpaper_wait_busy(panel); + + dev_info(drm->dev, "Panel idle after DTM command, starting data batch send.\n"); + + for (i = 0; i < PIXPAPER_HEIGHT; i++) { + for (j = 0; j < PANEL_BUFFER_TWO_BYTES_PER_ROW; j++) { + u8 packed_byte = pack_pixels_to_byte(src_pixels, i, j, fb); + + pixpaper_wait_busy(panel); + pixpaper_send_data(panel, packed_byte); + } + } + pixpaper_wait_busy(panel); + + dev_info(drm->dev, "Sending PON + 0x00 before DRF\n"); + ret = pixpaper_send_cmd(panel, PIXPAPER_CMD_POWER_ON); + if (ret) + goto update_cleanup; + ret = pixpaper_send_data(panel, 0x00); + if (ret) { + dev_err(drm->dev, "Failed sending data after PON-before-DRF: %d\n", ret); + goto update_cleanup; + } + usleep_range(10000, 11000); + pixpaper_wait_busy(panel); + + dev_info(drm->dev, "Triggering display refresh (DRF)\n"); + ret = pixpaper_send_cmd(panel, PIXPAPER_CMD_DISPLAY_REFRESH); + if (ret) + goto update_cleanup; + ret = pixpaper_send_data(panel, 0x00); + if (ret) { + dev_err(drm->dev, "Failed sending data after DRF: %d\n", ret); + goto update_cleanup; + } + usleep_range(10000, 11000); + pixpaper_wait_busy(panel); + + dev_info(drm->dev, "Frame update completed and refresh triggered\n"); + +update_cleanup: + if (vaddr && !IS_ERR(vaddr)) + dma_buf_vunmap(dmabuf, vaddr); + if (dmabuf && !IS_ERR(dmabuf)) + dma_buf_put(dmabuf); + + if (ret && ret != -ETIMEDOUT) + dev_err(drm->dev, "Frame update function failed with error %d\n", ret); + + mutex_unlock(&panel->update_lock); +} + + +static const struct drm_simple_display_pipe_funcs pixpaper_pipe_funcs = { + .enable = pixpaper_pipe_enable, + .disable = pixpaper_pipe_disable, + .update = pixpaper_pipe_update, + .prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb, +}; + +static int pixpaper_connector_get_modes(struct drm_connector *connector) +{ + struct drm_display_mode *mode; + + dev_info(connector->dev->dev, + "%s: CALLED for connector %s (id: %d)\n", __func__, + connector->name, connector->base.id); + + mode = drm_mode_create(connector->dev); + if (!mode) { + DRM_ERROR("Failed to create mode for connector %s\n", connector->name); + return 0; + } + + mode->hdisplay = PIXPAPER_WIDTH; + mode->vdisplay = PIXPAPER_HEIGHT; + + mode->htotal = mode->hdisplay + 80; + mode->hsync_start = mode->hdisplay + 8; + mode->hsync_end = mode->hdisplay + 8 + 32; + mode->vtotal = mode->vdisplay + 10; + mode->vsync_start = mode->vdisplay + 2; + mode->vsync_end = mode->vdisplay + 2 + 2; + + mode->clock = 6000; + + mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED; + drm_mode_set_name(mode); + + if (drm_mode_validate_size(mode, connector->dev->mode_config.max_width, + connector->dev->mode_config.max_height) != MODE_OK) { + DRM_WARN("%s: Mode %s (%dx%d) failed size validation against max %dx%d\n", __func__, + mode->name, mode->hdisplay, mode->vdisplay, + connector->dev->mode_config.max_width, + connector->dev->mode_config.max_height); + drm_mode_destroy(connector->dev, mode); + return 0; + } + + drm_mode_probed_add(connector, mode); + dev_info(connector->dev->dev, "%s: Added mode '%s' (%dx%d@%d) to connector %s\n", __func__, + mode->name, mode->hdisplay, mode->vdisplay, drm_mode_vrefresh(mode), + connector->name); + + connector->display_info.width_mm = 30; + connector->display_info.height_mm = 47; + + return 1; +} +static const struct drm_connector_helper_funcs pixpaper_conn_helpers = { + .get_modes = pixpaper_connector_get_modes, +}; + +static const struct drm_connector_funcs pixpaper_conn_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, +}; + +DEFINE_DRM_GEM_CMA_FOPS(pixpaper_fops); + +static int pixpaper_mode_valid(struct drm_device *dev, + const struct drm_display_mode *mode) +{ + if (mode->hdisplay == PIXPAPER_WIDTH && + mode->vdisplay == PIXPAPER_HEIGHT) { + return MODE_OK; + } + dev_dbg(dev->dev, "Rejecting mode %dx%d (supports only %dx%d)\n", + mode->hdisplay, mode->vdisplay, PIXPAPER_WIDTH, PIXPAPER_HEIGHT); + return MODE_BAD; +} + +static const struct drm_mode_config_funcs pixpaper_mode_config_funcs = { + .fb_create = drm_gem_fb_create_with_dirty, + .mode_valid = pixpaper_mode_valid, + .atomic_check = drm_atomic_helper_check, + .atomic_commit = drm_atomic_helper_commit, +}; + +static struct drm_driver pixpaper_drm_driver = { + .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC, + .fops = &pixpaper_fops, + .name = "pixpaper", + .desc = "DRM driver for PIXPAPER e-ink", + .date = "2025-06-16", + .major = 1, + .minor = 0, + .dumb_create = drm_gem_cma_dumb_create, + DRM_GEM_CMA_DRIVER_OPS_VMAP, +}; + + +static int pixpaper_probe(struct spi_device *spi) +{ + struct device *dev = &spi->dev; + struct pixpaper_panel *panel; + struct drm_device *drm; + int ret; + + dev_info(dev, "Probing PIXPAPER panel driver\n"); + + panel = devm_drm_dev_alloc(dev, &pixpaper_drm_driver, struct pixpaper_panel, drm); + if (IS_ERR(panel)) { + ret = PTR_ERR(panel); + dev_err(dev, "Failed to allocate DRM device: %d\n", ret); + return ret; + } + panel->init_completed_successfully = false; + drm = &panel->drm; + panel->spi = spi; + spi_set_drvdata(spi, panel); + + mutex_init(&panel->spi_lock); + mutex_init(&panel->update_lock); + + spi->mode = SPI_MODE_0; + spi->bits_per_word = 8; + + if (!spi->max_speed_hz) { + dev_warn(dev, + "spi-max-frequency not specified in DT, using default %u Hz\n", + PIXPAPER_SPI_SPEED_DEFAULT); + spi->max_speed_hz = PIXPAPER_SPI_SPEED_DEFAULT; + } else { + dev_info(dev, "Using spi-max-frequency from DT: %u Hz\n", spi->max_speed_hz); + } + + ret = spi_setup(spi); + if (ret < 0) { + dev_err(dev, "SPI setup failed: %d\n", ret); + return ret; + } + dev_info(dev, "SPI setup OK (mode=%d, speed=%u Hz, bpw=%d)\n", + spi->mode, spi->max_speed_hz, spi->bits_per_word); + + if (!dev->dma_mask) + dev->dma_mask = &dev->coherent_dma_mask; + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32)); + if (ret) { + dev_err(dev, "Failed to set DMA mask: %d\n", ret); + return ret; + } + dev_dbg(dev, "DMA mask set\n"); + + panel->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(panel->reset)) + return dev_err_probe(dev, PTR_ERR(panel->reset), "Failed to get 'reset' GPIO\n"); + panel->busy = devm_gpiod_get(dev, "busy", GPIOD_IN); + if (IS_ERR(panel->busy)) + return dev_err_probe(dev, PTR_ERR(panel->busy), "Failed to get 'busy' GPIO\n"); + panel->dc = devm_gpiod_get(dev, "dc", GPIOD_OUT_HIGH); + if (IS_ERR(panel->dc)) + return dev_err_probe(dev, PTR_ERR(panel->dc), "Failed to get 'dc' GPIO\n"); + dev_info(dev, "All required GPIOs obtained successfully.\n"); + + ret = drmm_mode_config_init(drm); + if (ret) + return ret; + drm->mode_config.funcs = &pixpaper_mode_config_funcs; + drm->mode_config.min_width = PIXPAPER_WIDTH; + drm->mode_config.max_width = PIXPAPER_WIDTH; + drm->mode_config.min_height = PIXPAPER_HEIGHT; + drm->mode_config.max_height = PIXPAPER_HEIGHT; + + ret = drm_connector_init(drm, &panel->connector, &pixpaper_conn_funcs, + DRM_MODE_CONNECTOR_SPI); + if (ret) + return ret; + drm_connector_helper_add(&panel->connector, &pixpaper_conn_helpers); + panel->connector.polled = DRM_CONNECTOR_POLL_CONNECT; + + ret = drm_simple_display_pipe_init(drm, &panel->pipe, &pixpaper_pipe_funcs, + pixpaper_formats, ARRAY_SIZE(pixpaper_formats), + NULL, &panel->connector); + if (ret) + return ret; + drm_mode_config_reset(drm); + + ret = drm_dev_register(drm, 0); + if (ret) + return ret; + + drm_fbdev_generic_setup(drm, 32); + + dev_info(dev, "Initialized PIXPAPER panel driver successfully\n"); + return 0; +} + +static int pixpaper_remove(struct spi_device *spi) +{ + struct pixpaper_panel *panel = spi_get_drvdata(spi); + + if (!panel) + return -ENODEV; + + dev_info(&spi->dev, "Removing PIXPAPER panel driver\n"); + + drm_dev_unplug(&panel->drm); + drm_atomic_helper_shutdown(&panel->drm); + return 0; +} + +static const struct of_device_id pixpaper_dt_ids[] = { + { .compatible = "mayqueen,pixpaper" }, + {} +}; +MODULE_DEVICE_TABLE(of, pixpaper_dt_ids); + +static struct spi_driver pixpaper_spi_driver = { + .driver = { + .name = "pixpaper", + .of_match_table = pixpaper_dt_ids, + }, + .probe = pixpaper_probe, + .remove = pixpaper_remove, +}; + +module_spi_driver(pixpaper_spi_driver); + +MODULE_AUTHOR("LC Wang"); +MODULE_DESCRIPTION("DRM SPI driver for PIXPAPER e-ink panel"); +MODULE_LICENSE("GPL"); -- 2.34.1