Den 10.06.2021 15.25, skrev Linus Walleij:
This adds a new driver for the Samsung DB7430 DPI display controller as controlled over SPI.
Right now the only panel product we know that is using this display controller is the LMS397KF04 but there may be more.
This is the first regular panel driver making use of the MIPI DBI helper library. The DBI "device" portions can not be used because that code assumes the use of a single regulator and specific timings around the reset pulse that do not match the DB7430 datasheet.
Cc: Noralf Trønnes noralf@tronnes.org Cc: Paul Cercueil paul@crapouillou.net Cc: Doug Anderson dianders@chromium.org Signed-off-by: Linus Walleij linus.walleij@linaro.org
ChangeLog v3->v4:
- Managed to make use of the in-kernel DBI support to conjure and send 9bit DBI SPI messages.
When I moved the DBI code out of tinydrm I split it up into an interface part and a framebuffer part so panel drivers could use the interface part like you have done here.
- This cuts out a bit of overhead.
- Deeper integration with the DBI library is not done, as assumes too much about the device, such as being used as a stand-alone framebuffer (this device is not).
diff --git a/drivers/gpu/drm/panel/panel-samsung-db7430.c b/drivers/gpu/drm/panel/panel-samsung-db7430.c new file mode 100644 index 000000000000..c11b3da65896 --- /dev/null +++ b/drivers/gpu/drm/panel/panel-samsung-db7430.c
+/**
- struct db7430 - state container for a panel controlled by the DB7430
- controller
- */
+struct db7430 {
- /** @dev: the container device */
- struct device *dev;
- /** @dbi: the DBI bus abstraction handle */
- struct mipi_dbi dbi;
- /** @panel: the DRM panel instance for this device */
- struct drm_panel panel;
- /** @width: the width of this panel in mm */
- u32 width;
- /** @height: the height of this panel in mm */
- u32 height;
- /** @reset: reset GPIO line */
- struct gpio_desc *reset;
You can use dbi->reset.
- /** @regulators: VCCIO and VIO supply regulators */
- struct regulator_bulk_data regulators[2];
+};
+static int db7430_probe(struct spi_device *spi) +{
- struct device *dev = &spi->dev;
- struct db7430 *db;
- int ret;
- db = devm_kzalloc(dev, sizeof(*db), GFP_KERNEL);
- if (!db)
return -ENOMEM;- db->dev = dev;
- /*
* VCI is the analog voltage supply* VCCIO is the digital I/O voltage supply*/- db->regulators[0].supply = "vci";
- db->regulators[1].supply = "vccio";
- ret = devm_regulator_bulk_get(dev,
ARRAY_SIZE(db->regulators),db->regulators);- if (ret)
return dev_err_probe(dev, ret, "failed to get regulators\n");- db->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
- if (IS_ERR(db->reset)) {
ret = PTR_ERR(db->reset);return dev_err_probe(dev, ret, "no RESET GPIO\n");- }
- spi->bits_per_word = 9;
Do you need to set this? The DBI helper sets it on the SPI transfer if the SPI controller supports 9-bit or uses emulation code if not.
- /* Preserve e.g. SPI_3WIRE setting */
- spi->mode |= SPI_MODE_3;
You can use the DT properties 'spi-cpha' and 'spi-cpol' to set this.
- ret = spi_setup(spi);
So I don't think you need to call spi_setup() here.
This code as-is will fail on a SPI controller that doesn't support 9 bits per word, and the emulation code in the DBI helper won't be utilised.
With the comments considered:
Acked-by: Noralf Trønnes noralf@tronnes.org
Noralf.
- if (ret < 0)
return dev_err_probe(dev, ret, "spi setup failed\n");- ret = mipi_dbi_spi_init(spi, &db->dbi, NULL);
- if (ret)
return dev_err_probe(dev, ret, "MIPI DBI init failed\n");- drm_panel_init(&db->panel, dev, &db7430_drm_funcs,
DRM_MODE_CONNECTOR_DPI);- /* FIXME: if no external backlight, use internal backlight */
- ret = drm_panel_of_backlight(&db->panel);
- if (ret)
return dev_err_probe(dev, ret, "failed to add backlight\n");- spi_set_drvdata(spi, db);
- drm_panel_add(&db->panel);
- dev_dbg(dev, "added panel\n");
- return 0;
+}