On 1/25/22 11:57 AM, Noralf Trønnes wrote:
Add a driver that will work with most MIPI DBI compatible SPI panels.
This avoids adding a driver for every new MIPI DBI compatible controller
that is to be used by Linux. The 'compatible' Device Tree property with
a '.bin' suffix will be used to load a firmware file that contains the
controller configuration.

Example (driver will load sainsmart18.bin):

display@0 {
        compatible = "sainsmart18", "panel-mipi-dbi-spi";
        reg = <0>;
        reset-gpios = <&gpio 25 0>;
        dc-gpios = <&gpio 24 0>;
};


...

+static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
+{
+       struct device *dev = &spi->dev;
+       struct drm_display_mode mode;
+       struct mipi_dbi_dev *dbidev;
+       const struct firmware *fw;
+       const char *compatible;
+       struct drm_device *drm;
+       struct property *prop;
+       bool fw_found = false;
+       struct mipi_dbi *dbi;
+       struct gpio_desc *dc;
+       char fw_name[40];
+       int ret;
+
+       dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct 
mipi_dbi_dev, drm);
+       if (IS_ERR(dbidev))
+               return PTR_ERR(dbidev);
+
+       dbi = &dbidev->dbi;
+       drm = &dbidev->drm;
+
+       of_property_for_each_string(dev->of_node, "compatible", prop, 
compatible) {
+               snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible);
+
+               ret = firmware_request_nowarn(&fw, fw_name, dev);
+               if (ret) {
+                       drm_dbg(drm, "No config file found for compatible: '%s' 
(error=%d)\n",
+                               compatible, ret);
+                       continue;
+               }
+

Should we add a directory prefix to the firmware file name to avoid the 
possibility of
file name clashes with unrelated firmwares?

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