Re: [PATCH v3 4/6] drm/tinydrm: add support for LEGO MINDSTORMS EV3 LCD

Noralf Trønnes
2017-08-05T18:20:25Z

Den 04.08.2017 00.33, 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@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 <david@lechnology.com>
> +S: Maintained
> +F: drivers/gpu/drm/tinydrm/st7586.c
> +F: Documentation/devicetree/bindings/display/st7586.txt
> +

This file is sorted alphabetically, so it should go after SIS.
It seems REPAPER ended up in the wrong place after the conflict
resolution following Linus's cleanup.

> 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 <david@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,

Could you put a comment somewhere explaining what grey332 means, that
it's not
a 332 pixel format that I first thought, but that you store 3x 2-bit
pixles in one byte.

> + 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;

Something wrong here: 3 * 3.

> + clip->x2 = (clip->x2 + 2) / 3 * 3;

You can use DIV_ROUND_UP().

> +
> + 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;

I don't understand how this pixel packing matches the one described in
the datasheet. Why do you flip the bits at the end?

> + }
> + }
> +
> + /* 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;

You don't need this default, because you can only get the ones in
st7586_formats.

> + }
> +
> + if (import_attach)
> + dma_buf_end_cpu_access(import_attach->dmabuf, DMA_FROM_DEVICE);

ret = dma_buf_end_cpu_access(...)

> +
> + 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;
> +

reset and dc is required following our discussion:

> + 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)
> +};

I checked davinci_all_defconfig and CONFIG_PM is not set.
If the board can't suspend, then you don't need this.

> +
> +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 <david@lechnology.com>");
> +MODULE_LICENSE("GPL");