Date:   Tue, 18 Oct 2022 18:45:26 +0200
From:   Tommaso Merciai <tommaso.merciai@...rulasolutions.com>
To:     tommaso.merciai@...rulasolutions.com
Cc:     michael@...rulasolutions.com, linuxfancy@...glegroups.com,
        linux-amarula@...rulasolutions.com, kamlesh.gurudasani@...il.com,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Maxime Ripard <maxime@...no.tech>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Javier Martinez Canillas <javierm@...hat.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Noralf Trønnes <noralf@...nnes.org>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: [PATCH 2/2] drm/tiny: add support for tft displays based on ilitek,ili9488

This adds support for ilitek,ili9488 based displays with shift register
in front of controller. Waveshare,pico-restouch-lcd-3.5 are such displays

Signed-off-by: Tommaso Merciai <tommaso.merciai@...rulasolutions.com>
---
 drivers/gpu/drm/tiny/Kconfig   |  13 +
 drivers/gpu/drm/tiny/Makefile  |   1 +
 drivers/gpu/drm/tiny/ili9488.c | 440 +++++++++++++++++++++++++++++++++
 3 files changed, 454 insertions(+)
 create mode 100644 drivers/gpu/drm/tiny/ili9488.c

diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
index 027cd87c3d0d7..6e708e8414806 100644
--- a/drivers/gpu/drm/tiny/Kconfig
+++ b/drivers/gpu/drm/tiny/Kconfig
@@ -148,6 +148,19 @@ config TINYDRM_ILI9486
 
 	  If M is selected the module will be called ili9486.
 
+config TINYDRM_ILI9488
+	tristate "DRM support for ILI9488 display panels"
+	depends on DRM && SPI
+	select DRM_KMS_HELPER
+	select DRM_GEM_CMA_HELPER
+	select DRM_MIPI_DBI
+	select BACKLIGHT_CLASS_DEVICE
+	help
+	  DRM driver for the following Ilitek ILI9488 panels:
+	  * LCD 3.5" 320x480 TFT (Waveshare Pico-ResTouch-LCD-3.5")
+
+	  If M is selected the module will be called ili9486.
+
 config TINYDRM_MI0283QT
 	tristate "DRM support for MI0283QT"
 	depends on DRM && SPI
diff --git a/drivers/gpu/drm/tiny/Makefile b/drivers/gpu/drm/tiny/Makefile
index 1d9d6227e7ab7..aad6683b2ac40 100644
--- a/drivers/gpu/drm/tiny/Makefile
+++ b/drivers/gpu/drm/tiny/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_TINYDRM_ILI9163)		+= ili9163.o
 obj-$(CONFIG_TINYDRM_ILI9225)		+= ili9225.o
 obj-$(CONFIG_TINYDRM_ILI9341)		+= ili9341.o
 obj-$(CONFIG_TINYDRM_ILI9486)		+= ili9486.o
+obj-$(CONFIG_TINYDRM_ILI9488)		+= ili9488.o
 obj-$(CONFIG_TINYDRM_MI0283QT)		+= mi0283qt.o
 obj-$(CONFIG_TINYDRM_REPAPER)		+= repaper.o
 obj-$(CONFIG_TINYDRM_ST7586)		+= st7586.o
diff --git a/drivers/gpu/drm/tiny/ili9488.c b/drivers/gpu/drm/tiny/ili9488.c
new file mode 100644
index 0000000000000..b94d9d4ff4544
--- /dev/null
+++ b/drivers/gpu/drm/tiny/ili9488.c
@@ -0,0 +1,440 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * DRM driver for Ilitek ILI9488 panels
+ *
+ * Copyright 2020 Kamlesh Gurudasani <kamlesh.gurudasani@...il.com>
+ */
+
+#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/drm_atomic_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fb_cma_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_damage_helper.h>
+#include <drm/drm_framebuffer.h>
+#include <drm/drm_gem_atomic_helper.h>
+#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_managed.h>
+#include <drm/drm_mipi_dbi.h>
+#include <drm/drm_modeset_helper.h>
+
+#define ILI9488_VCOM_CONTROL_1			0xC5
+#define ILI9488_COLUMN_ADDRESS_SET		0x2A
+#define ILI9488_PAGE_ADDRESS_SET		0x2B
+#define ILI9488_MEMORY_WRITE			0x2C
+#define ILI9488_POSITIVE_GAMMA_CORRECTION	0xE0
+#define ILI9488_NEGATIVE_GAMMA_CORRECTION	0xE1
+#define ILI9488_POWER_CONTROL_1			0xC0
+#define ILI9488_POWER_CONTROL_2			0xC1
+#define ILI9488_POWER_CONTROL_3			0xC2
+#define ILI9488_MEM_ACCESS_CONTROL		0x36
+#define ILI9488_COLMOD_PIXEL_FORMAT_SET		0x3A
+#define ILI9488_INTERFACE_MODE_CONTROL		0xB0
+#define ILI9488_FRAME_RATE_CONTROL_PARTIAL	0xB3
+#define ILI9488_DISPLAY_INVERSION_ON		0x21
+#define ILI9488_DISPLAY_INVERSION_CONTROL	0xB4
+#define ILI9488_DISPLAY_FUNCTION_CONTROL	0xB6
+#define ILI9488_ENTRY_MODE_SET			0xB7
+#define ILI9488_HS_LANES_CONTROL		0xBE
+#define ILI9488_SET_IMAGE_FUNCTION		0xE9
+#define ILI9488_ADJUST_CONTROL_3		0xF7
+#define ILI9488_DISPLAY_ON			0x29
+#define ILI9488_DISPLAY_OFF			0x28
+#define ILI9488_ENTER_SLEEP_MODE		0x10
+#define ILI9488_DBI_BPP18			0x06
+#define ILI9488_DBI_BPP16			0x05
+#define ILI9488_DPI_BPP24			0x70
+#define ILI9488_DPI_BPP18			0x60
+#define ILI9488_DPI_BPP16			0x50
+#define ILI9488_FRAME_RATE_CONTROL_NORMAL	0xB1
+#define ILI9488_SLEEP_OUT			0x11
+
+#define ILI9488_MADCTL_RGB	BIT(2)
+#define ILI9488_MADCTL_BGR	BIT(3)
+#define ILI9488_MADCTL_MV	BIT(5)
+#define ILI9488_MADCTL_MX	BIT(6)
+#define ILI9488_MADCTL_MY	BIT(7)
+
+static void ili9488_rgb565_to_rgb666_line(u8 *dst, u16 *sbuf,
+					  unsigned int pixels)
+{
+	unsigned int x;
+
+	for (x = 0; x < pixels; x++) {
+		*dst++ = ((*sbuf & 0xF800) >> 8);
+		*dst++ = ((*sbuf & 0x07E0) >> 3);
+		*dst++ = ((*sbuf & 0x001F) << 3);
+		sbuf++;
+	}
+}
+
+static void ili9488_rgb565_to_rgb666(u8 *dst, void *vaddr,
+				     struct drm_framebuffer *fb,
+				     struct drm_rect *rect)
+{
+	unsigned long linepixels = drm_rect_width(rect);
+	unsigned long lines = drm_rect_height(rect);
+	size_t dst_len = linepixels * 3;
+	size_t src_len = linepixels * fb->format->cpp[0];
+	unsigned int y;
+	u16 *sbuf;
+
+	/*
+	 * The cma memory is write-combined so reads are uncached.
+	 * Speed up by fetching one line at a time.
+	 */
+	sbuf = kmalloc(src_len, GFP_KERNEL);
+	if (!sbuf)
+		return;
+
+	memset(sbuf, 0, src_len);
+
+	vaddr += rect->y1 * fb->pitches[0] + rect->x1 * fb->format->cpp[0];
+	for (y = 0; y < lines; y++) {
+		memcpy(sbuf, vaddr, src_len);
+		ili9488_rgb565_to_rgb666_line(dst, sbuf, linepixels);
+		vaddr += fb->pitches[0];
+		dst += dst_len;
+	}
+	kfree(sbuf);
+}
+
+static int ili9488_buf_copy(void *dst, struct drm_framebuffer *fb,
+			    struct drm_rect *rect)
+{
+	struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
+	void *src = cma_obj->vaddr;
+	int ret = 0;
+
+	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
+	if (ret)
+		return ret;
+
+	switch (fb->format->format) {
+	case DRM_FORMAT_RGB565:
+		ili9488_rgb565_to_rgb666(dst, src, fb, rect);
+		break;
+	default:
+		dev_err_once(fb->dev->dev, "Format is not supported: %p4cc\n",
+				&fb->format->format);
+		return -EINVAL;
+	}
+
+	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
+
+	return ret;
+}
+
+static void ili9488_dbi_set_window_address(struct mipi_dbi_dev *dbidev,
+					unsigned int xs, unsigned int xe,
+					unsigned int ys, unsigned int ye)
+{
+	struct mipi_dbi *dbi = &dbidev->dbi;
+
+	xs += dbidev->left_offset;
+	xe += dbidev->left_offset;
+	ys += dbidev->top_offset;
+	ye += dbidev->top_offset;
+
+	mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS, (xs >> 8) & 0xff,
+			 xs & 0xff, (xe >> 8) & 0xff, xe & 0xff);
+	mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS, (ys >> 8) & 0xff,
+			 ys & 0xff, (ye >> 8) & 0xff, ye & 0xff);
+}
+
+static void ili9488_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
+{
+	struct iosys_map map[DRM_FORMAT_MAX_PLANES];
+	struct iosys_map data[DRM_FORMAT_MAX_PLANES];
+	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
+	unsigned int height = rect->y2 - rect->y1;
+	unsigned int width = rect->x2 - rect->x1;
+	struct mipi_dbi *dbi = &dbidev->dbi;
+	int idx, ret = 0;
+	bool full;
+	void *tr;
+
+	if (WARN_ON(!fb))
+		return;
+
+	if (!drm_dev_enter(fb->dev, &idx))
+		return;
+
+	ret = drm_gem_fb_vmap(fb, map, data);
+	if (ret)
+		goto err_drm_dev_exit;
+
+	full = width == fb->width && height == fb->height;
+
+	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
+
+	if (!dbi->dc || !full ||
+	    fb->format->format == DRM_FORMAT_RGB565) {
+		tr = dbidev->tx_buf;
+		ret = ili9488_buf_copy(dbidev->tx_buf, fb, rect);
+		if (ret)
+			goto err_msg;
+	} else {
+		tr = data[0].vaddr; /* TODO: Use mapping abstraction properly */
+	}
+
+	ili9488_dbi_set_window_address(dbidev, rect->x1, rect->x2 - 1, rect->y1,
+				    rect->y2 - 1);
+
+	ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START, tr,
+				   width * height * 3);
+err_msg:
+	if (ret)
+		drm_err_once(fb->dev, "Failed to update display %d\n", ret);
+
+	drm_gem_fb_vunmap(fb, map);
+
+err_drm_dev_exit:
+	drm_dev_exit(idx);
+}
+
+static void ili9488_pipe_update(struct drm_simple_display_pipe *pipe,
+			       struct drm_plane_state *old_state)
+{
+	struct drm_plane_state *state = pipe->plane.state;
+	struct drm_rect rect;
+
+	if (!pipe->crtc.state->active)
+		return;
+
+	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
+		ili9488_fb_dirty(state->fb, &rect);
+}
+
+static void ili9488_pipe_enable(struct drm_simple_display_pipe *pipe,
+				struct drm_crtc_state *crtc_state,
+				struct drm_plane_state *plane_state)
+{
+	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
+	struct drm_framebuffer *fb = plane_state->fb;
+	struct mipi_dbi *dbi = &dbidev->dbi;
+	u8 addr_mode;
+	struct drm_rect rect = {
+		.x1 = 0,
+		.x2 = fb->width,
+		.y1 = 0,
+		.y2 = fb->height,
+	};
+	int ret, idx;
+
+	if (!drm_dev_enter(pipe->crtc.dev, &idx))
+		return;
+
+	DRM_DEBUG_KMS("\n");
+
+	ret = mipi_dbi_poweron_conditional_reset(dbidev);
+	if (ret < 0)
+		goto out_exit;
+	if (ret == 1)
+		goto out_enable;
+
+	mipi_dbi_command(dbi, ILI9488_DISPLAY_INVERSION_ON);
+	mipi_dbi_command(dbi, ILI9488_POWER_CONTROL_3, 0x33);
+	mipi_dbi_command(dbi, ILI9488_FRAME_RATE_CONTROL_NORMAL, 0xB0);
+	mipi_dbi_command(dbi, ILI9488_MEM_ACCESS_CONTROL, 0x28);
+
+	mipi_dbi_command(dbi, MIPI_DCS_SET_PIXEL_FORMAT, 0x65);
+
+	mipi_dbi_command(dbi, ILI9488_POSITIVE_GAMMA_CORRECTION,
+			 0x00, 0x13, 0x18, 0x04, 0x0F,
+			 0x06, 0x3A, 0x56, 0x4D, 0x03,
+			 0x0A, 0x06, 0x30, 0x3E, 0x0F);
+	mipi_dbi_command(dbi, ILI9488_NEGATIVE_GAMMA_CORRECTION,
+			 0x00, 0x13, 0x18, 0x01, 0x11,
+			 0x06, 0x38, 0x3A, 0x4D, 0x06,
+			 0x0D, 0x0B, 0x31, 0x37, 0x0F);
+
+	mipi_dbi_command(dbi, MIPI_DCS_SET_PIXEL_FORMAT, MIPI_DCS_PIXEL_FMT_18BIT);
+	mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
+	msleep(120);
+	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
+	msleep(100);
+
+out_enable:
+	switch (dbidev->rotation) {
+	default:
+		addr_mode = ILI9488_MADCTL_MX;
+		break;
+	case 90:
+		addr_mode = ILI9488_MADCTL_MV;
+		break;
+	case 180:
+		addr_mode = ILI9488_MADCTL_MY;
+		break;
+	case 270:
+		addr_mode = ILI9488_MADCTL_MV | ILI9488_MADCTL_MY |
+			ILI9488_MADCTL_MX;
+		break;
+	}
+	addr_mode |= ILI9488_MADCTL_BGR;
+	mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
+	ili9488_fb_dirty(fb, &rect);
+out_exit:
+	drm_dev_exit(idx);
+}
+
+static void ili9488_pipe_disable(struct drm_simple_display_pipe *pipe)
+{
+	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
+	/*
+	 * This callback is not protected by drm_dev_enter/exit since we want to
+	 * turn off the display on regular driver unload. It's highly unlikely
+	 * that the underlying SPI controller is gone should this be called
+	 * after unplug.
+	 */
+
+	DRM_DEBUG_KMS("\n");
+
+	mipi_dbi_command(&dbidev->dbi, MIPI_DCS_SET_DISPLAY_OFF);
+}
+
+static const u32 ili9488_formats[] = {
+	DRM_FORMAT_RGB565,
+};
+
+static const struct drm_simple_display_pipe_funcs ili9488_pipe_funcs = {
+	.enable = ili9488_pipe_enable,
+	.disable = ili9488_pipe_disable,
+	.update = ili9488_pipe_update,
+};
+
+static const struct drm_display_mode ili9488_mode = {
+	DRM_SIMPLE_MODE(320, 480, 49, 73),
+};
+
+DEFINE_DRM_GEM_CMA_FOPS(ili9488_fops);
+
+static struct drm_driver ili9488_driver = {
+	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
+	.fops			= &ili9488_fops,
+	DRM_GEM_CMA_DRIVER_OPS_VMAP,
+	.debugfs_init		= mipi_dbi_debugfs_init,
+	.name			= "ili9488",
+	.desc			= "Ilitek ILI9488",
+	.date			= "20221017",
+	.major			= 1,
+	.minor			= 0,
+};
+
+static const struct of_device_id ili9488_of_match[] = {
+	{ .compatible = "waveshare,pico-rt-lcd-35" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ili9488_of_match);
+
+static const struct spi_device_id ili9488_id[] = {
+	{ "ili9488", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ili9488_id);
+
+static int ili9488_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct mipi_dbi_dev *dbidev;
+	struct drm_device *drm;
+	struct mipi_dbi *dbi;
+	struct gpio_desc *dc;
+	u32 rotation = 0;
+	size_t bufsize;
+	int ret;
+
+	dbidev = devm_drm_dev_alloc(dev, &ili9488_driver,
+				    struct mipi_dbi_dev, drm);
+	if (IS_ERR(dbidev))
+		return PTR_ERR(dbidev);
+
+	dbi = &dbidev->dbi;
+	drm = &dbidev->drm;
+
+	bufsize = ili9488_mode.vdisplay * ili9488_mode.hdisplay * 3;
+
+	dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR(dbi->reset)) {
+		DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
+		return PTR_ERR(dbi->reset);
+	}
+
+	dc = devm_gpiod_get(dev, "dc", GPIOD_OUT_LOW);
+	if (IS_ERR(dc)) {
+		DRM_DEV_ERROR(dev, "Failed to get gpio 'dc'\n");
+		return PTR_ERR(dc);
+	}
+
+	dbidev->backlight = devm_of_find_backlight(dev);
+	if (IS_ERR(dbidev->backlight))
+		return PTR_ERR(dbidev->backlight);
+
+	device_property_read_u32(dev, "rotation", &rotation);
+
+	ret = mipi_dbi_spi_init(spi, dbi, dc);
+	if (ret)
+		return ret;
+
+	dbidev->drm.mode_config.preferred_depth = 16;
+
+	ret = mipi_dbi_dev_init_with_formats(dbidev, &ili9488_pipe_funcs,
+					     ili9488_formats,
+					     ARRAY_SIZE(ili9488_formats),
+					     &ili9488_mode, rotation, bufsize);
+	if (ret)
+		return ret;
+
+	dbi->swap_bytes = true;
+	drm_mode_config_reset(drm);
+
+	ret = drm_dev_register(drm, 0);
+	if (ret)
+		return ret;
+
+	spi_set_drvdata(spi, drm);
+
+	drm_fbdev_generic_setup(drm, 0);
+
+	return 0;
+}
+
+static void ili9488_remove(struct spi_device *spi)
+{
+	struct drm_device *drm = spi_get_drvdata(spi);
+
+	drm_dev_unplug(drm);
+	drm_atomic_helper_shutdown(drm);
+}
+
+static void ili9488_shutdown(struct spi_device *spi)
+{
+	drm_atomic_helper_shutdown(spi_get_drvdata(spi));
+}
+
+static struct spi_driver ili9488_spi_driver = {
+	.driver = {
+		.name = "ili9488",
+		.owner = THIS_MODULE,
+		.of_match_table = ili9488_of_match,
+	},
+	.id_table = ili9488_id,
+	.probe = ili9488_probe,
+	.remove = ili9488_remove,
+	.shutdown = ili9488_shutdown,
+};
+module_spi_driver(ili9488_spi_driver);
+
+MODULE_DESCRIPTION("Ilitek ILI9488 DRM driver");
+MODULE_AUTHOR("Kamlesh Gurudasani <kamlesh.gurudasani@...il.com>");
+MODULE_AUTHOR("Michael Trimarchi <michael@...rulasolutions.com>");
+MODULE_AUTHOR("Tommaso Merciai <tommaso.merciai@...rulasolutions.com>");
+MODULE_LICENSE("GPL");
\ No newline at end of file
-- 
2.25.1

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