[PATCH 2/2] drm/tinydrm: add support for ilitek,ili9486 based displays with regwidth=16
Noralf Trønnes
noralf at tronnes.org
Sat Jan 25 17:30:19 UTC 2020
Hi Kamlesh,
Nice to see this driver, this means I can now drop the piscreen driver
from the out-of-tree tinydrm repo.
Den 25.01.2020 16.38, skrev Kamlesh Gurudasani:
> This adds support fot ilitek,ili9486 based display with shift register in front
s/fot/for/
> of controller, basically with regwidth=16
The last part of this sentence only makes sense for people that know
fbtft. Either add a reference to fbtft or just drop it.
>
> Signed-off-by: Kamlesh Gurudasani <kamlesh.gurudasani at gmail.com>
> ---
<snip>
> diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
> index a46ac28..fe135cd 100644
> --- a/drivers/gpu/drm/tiny/Kconfig
> +++ b/drivers/gpu/drm/tiny/Kconfig
> @@ -47,6 +47,20 @@ config TINYDRM_ILI9341
>
> If M is selected the module will be called ili9341.
>
> +config TINYDRM_ILI9486
> + tristate "DRM support for ILI9486 display panels"
> + depends on DRM && SPI
> + select DRM_KMS_HELPER
> + select DRM_KMS_CMA_HELPER
> + select DRM_MIPI_DBI
> + select BACKLIGHT_CLASS_DEVICE
> + help
> + DRM driver for the following Ilitek ILI486 panels:
s/ILI486/ILI9486/
> + * PISCREEN 3.5" 320x480 TFT (Ozzmaker 3.5")
> + * RPILCD 3.5" 320x480 TFT (Waveshare 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 896cf31..1f8a0f0 100644
> --- a/drivers/gpu/drm/tiny/Makefile
> +++ b/drivers/gpu/drm/tiny/Makefile
> @@ -8,3 +8,4 @@ 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_TINYDRM_ILI9486) += ili9486.o
Please keep the entries sorted alphabetically.
> diff --git a/drivers/gpu/drm/tiny/ili9486.c b/drivers/gpu/drm/tiny/ili9486.c
> new file mode 100644
> index 0000000..bed83b0
> --- /dev/null
> +++ b/drivers/gpu/drm/tiny/ili9486.c
> @@ -0,0 +1,288 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * DRM driver for Ilitek ILI9486 panels
> + *
> + * Copyright 2018 Kamlesh Gurudasani <kamlesh.gurudasani at gmail.com>
2020?
> + *
> + * Some code copied from mipi-dbi.c
> + * Copyright 2016 Noralf Tronnes
You can drop this last paragraph, I see that you've copied it from
ili9225, but these tiny drivers are just more or less boilerplate
drivers with very little special stuff.
> + */
> +
> +#include <linux/backlight.h>
> +#include <linux/delay.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_helper.h>
> +#include <drm/drm_gem_cma_helper.h>
> +#include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_mipi_dbi.h>
> +#include <drm/drm_modeset_helper.h>
> +
> +#define ILI9486_ITFCTR1 0xb0
> +#define ILI9486_PWCTRL1 0xc2
> +#define ILI9486_VMCTRL1 0xc5
> +#define ILI9486_PGAMCTRL 0xe0
> +#define ILI9486_NGAMCTRL 0xe1
> +#define ILI9486_DGAMCTRL 0xe2
> +#define ILI9486_MADCTL_BGR BIT(3)
> +#define ILI9486_MADCTL_MV BIT(5)
> +#define ILI9486_MADCTL_MX BIT(6)
> +#define ILI9486_MADCTL_MY BIT(7)
> +
> +/*
> + * The PiScreen/waveshare rpi-lcd-35 has a SPI to 16-bit parallel bus converter
> + * in front of the display controller. This means that 8-bit values has to be
s/has/have/
> + * transferred as 16-bit.
> + */
> +static int ili9486_command(struct mipi_dbi *mipi, u8 *cmd, u8 *par, size_t num)
The function name here is misleading, the ili9486 can use the default in
drm_mipi_dbi when used in SPI mode, so you should name it
piscreen_command or waveshare_command since it's special for those displays.
> +{
> + struct spi_device *spi = mipi->spi;
> + void *data = par;
> + u32 speed_hz;
> + unsigned int bpw = 8;
> + int i, ret;
> + u16 *buf;
> +
> + buf = kmalloc(32 * sizeof(u16), GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> + /*
> + * The Raspberry Pi supports only 8-bit on the DMA capable SPI
> + * controller and is little endian, so byte swapping is needed.
> + */
I found this comment a bit confusing at first, then I realised that I
wrote it myself in the piscreen driver. I think we should expand a
little here to make it clear that these displays are made for the Pi.
Maybe something like this:
The displays are Raspberry Pi HATs and connected to the 8-bit only SPI
controller so 16-bit command and parameters need byte swapping before
being transferred as 8-bit on the big endian SPI bus.
Pixel data bytes have already been swapped before this function is called.
> + buf[0] = cpu_to_be16(*cmd);
> + gpiod_set_value_cansleep(mipi->dc, 0);
> + speed_hz = mipi_dbi_spi_cmd_max_speed(spi, 2);
> + ret = mipi_dbi_spi_transfer(spi, speed_hz, bpw, buf, 2);
You don't change bpw, so you can drop the variable and use the value
directly.
> + if (ret || !num)
> + goto free;
> +
> + /* 8-bit configuration data, not 16-bit pixel data */
> + if (num <= 32) {
> + for (i = 0; i < num; i++)
> + buf[i] = cpu_to_be16(par[i]);
> + num *= 2;
> + speed_hz = mipi_dbi_spi_cmd_max_speed(spi, num);
> + data = buf;
> + }
> +
> + gpiod_set_value_cansleep(mipi->dc, 1);
> + ret = mipi_dbi_spi_transfer(spi, speed_hz, bpw, data, num);
> + free:
> + kfree(buf);
> +
> + return ret;
> +}
> +
> +static void ili9486_enable(struct drm_simple_display_pipe *pipe,
Please change the function name here as well. The enable function is
always display specific.
> + 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 mipi_dbi *dbi = &dbidev->dbi;
> + u8 addr_mode;
> + 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, ILI9486_ITFCTR1);
> + mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
> + msleep(250);
> +
> + /* Interface Pixel Format */
> + mipi_dbi_command(dbi, MIPI_DCS_SET_PIXEL_FORMAT, 0x55);
> +
> + /* Power Control 3 */
The comment doesn't match the macro.
I think you can drop these comments, the macros (almost) says it all.
> + mipi_dbi_command(dbi, ILI9486_PWCTRL1, 0x44);
> +
> + /* VCOM Control 1 */
> + mipi_dbi_command(dbi, ILI9486_VMCTRL1, 0x00, 0x00, 0x00, 0x00);
> +
> + /* PGAMCTRL(Positive Gamma Control) */
> + mipi_dbi_command(dbi, ILI9486_PGAMCTRL,
> + 0x0F, 0x1F, 0x1C, 0x0C, 0x0F, 0x08, 0x48, 0x98,
> + 0x37, 0x0A, 0x13, 0x04, 0x11, 0x0D, 0x0);
> + mipi_dbi_command(dbi, ILI9486_NGAMCTRL,
> + 0x0F, 0x32, 0x2E, 0x0B, 0x0D, 0x05, 0x47, 0x75,
> + 0x37, 0x06, 0x10, 0x03, 0x24, 0x20, 0x00);
> + mipi_dbi_command(dbi, ILI9486_DGAMCTRL,
> + 0x0F, 0x32, 0x2E, 0x0B, 0x0D, 0x05, 0x47, 0x75,
> + 0x37, 0x06, 0x10, 0x03, 0x24, 0x20, 0x00);
> +
> + mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
> + msleep(100);
> +
> + out_enable:
> + switch (dbidev->rotation) {
> + case 90:
> + addr_mode = ILI9486_MADCTL_MY;
> + break;
> + case 180:
> + addr_mode = ILI9486_MADCTL_MV;
> + break;
> + case 270:
> + addr_mode = ILI9486_MADCTL_MX;
> + break;
> + default:
> + addr_mode = ILI9486_MADCTL_MV | ILI9486_MADCTL_MY |
> + ILI9486_MADCTL_MX;
> + break;
> + }
> + addr_mode |= ILI9486_MADCTL_BGR;
> + mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
> + mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
> + out_exit:
> + drm_dev_exit(idx);
> +}
> +
> +static const struct drm_simple_display_pipe_funcs ili9486_pipe_funcs = {
Pipe funcs are also display specific.
> + .enable = ili9486_enable,
> + .disable = mipi_dbi_pipe_disable,
> + .update = mipi_dbi_pipe_update,
> + .prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
> +};
> +
> +static const struct drm_display_mode ili9486_mode = {
Display specific.
> + DRM_SIMPLE_MODE(480, 320, 73, 49),
> +};
> +
> +DEFINE_DRM_GEM_CMA_FOPS(ili9486_fops);
> +
> +static struct drm_driver ili9486_driver = {
> + .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
> + .fops = &ili9486_fops,
> + .release = mipi_dbi_release,
> + DRM_GEM_CMA_VMAP_DRIVER_OPS,
> + .debugfs_init = mipi_dbi_debugfs_init,
> + .name = "ili9486",
> + .desc = "Ilitek ILI9486",
> + .date = "20200118",
> + .major = 1,
> + .minor = 0,
> +};
> +
> +static const struct of_device_id ili9486_of_match[] = {
> + { .compatible = "waveshare,rpi-lcd-35" },
> + { .compatible = "ozzmaker,piscreen" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, ili9486_of_match);
> +
> +static const struct spi_device_id ili9486_id[] = {
> + { "ili9486", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(spi, ili9486_id);
> +
> +static int ili9486_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;
> + int ret;
> +
> + dbidev = kzalloc(sizeof(*dbidev), GFP_KERNEL);
> + if (!dbidev)
> + return -ENOMEM;
> +
> + dbi = &dbidev->dbi;
> + drm = &dbidev->drm;
> + ret = devm_drm_dev_init(dev, drm, &ili9486_driver);
> + if (ret) {
> + kfree(dbidev);
> + return ret;
> + }
> +
> + drm_mode_config_init(drm);
> +
> + dbi->reset = devm_gpiod_get_optional(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_optional(dev, "dc", GPIOD_OUT_LOW);
I don't think DC is optional on these displays?
> + 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;
> +
> + ret = mipi_dbi_dev_init(dbidev, &ili9486_pipe_funcs, &ili9486_mode, rotation);
> + if (ret)
> + return ret;
> +
> + drm_mode_config_reset(drm);
> +
> + ret = drm_dev_register(drm, 0);
> + if (ret)
> + return ret;
> +
> + dbi->command = ili9486_command;
> + dbi->read_commands = NULL;
You can't change these after the device has been registered, put the
assignements between mipi_dbi_spi_init and mipi_dbi_dev_init.
Noralf.
> +
> + spi_set_drvdata(spi, drm);
> +
> + drm_fbdev_generic_setup(drm, 0);
> +
> + return 0;
> +}
> +
> +static int ili9486_remove(struct spi_device *spi)
> +{
> + struct drm_device *drm = spi_get_drvdata(spi);
> +
> + drm_dev_unplug(drm);
> + drm_atomic_helper_shutdown(drm);
> +
> + return 0;
> +}
> +
> +static void ili9486_shutdown(struct spi_device *spi)
> +{
> + drm_atomic_helper_shutdown(spi_get_drvdata(spi));
> +}
> +
> +static struct spi_driver ili9486_spi_driver = {
> + .driver = {
> + .name = "ili9486",
> + .of_match_table = ili9486_of_match,
> + },
> + .id_table = ili9486_id,
> + .probe = ili9486_probe,
> + .remove = ili9486_remove,
> + .shutdown = ili9486_shutdown,
> +};
> +module_spi_driver(ili9486_spi_driver);
> +
> +MODULE_DESCRIPTION("Ilitek ILI9486 DRM driver");
> +MODULE_AUTHOR("Kamlesh Gurudasani <kamlesh.gurudasani at gmail.com>");
> +MODULE_LICENSE("GPL");
>
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