linux/drivers/gpu/drm/solomon/ssd130x-spi.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * DRM driver for Solomon SSD13xx OLED displays (SPI bus)
 *
 * Copyright 2022 Red Hat Inc.
 * Authors: Javier Martinez Canillas <[email protected]>
 */
#include <linux/spi/spi.h>
#include <linux/module.h>

#include "ssd130x.h"

#define DRIVER_NAME …
#define DRIVER_DESC …

struct ssd130x_spi_transport { … };

/*
 * The regmap bus .write handler, it is just a wrapper around spi_write()
 * but toggling the Data/Command control pin (D/C#). Since for 4-wire SPI
 * a D/C# pin is used, in contrast with I2C where a control byte is sent,
 * prior to every data byte, that contains a bit with the D/C# value.
 *
 * These control bytes are considered registers by the ssd130x core driver
 * and can be used by the ssd130x SPI driver to determine if the data sent
 * is for a command register or for the Graphic Display Data RAM (GDDRAM).
 */
static int ssd130x_spi_write(void *context, const void *data, size_t count)
{ … }

/* The ssd130x driver does not read registers but regmap expects a .read */
static int ssd130x_spi_read(void *context, const void *reg, size_t reg_size,
			    void *val, size_t val_size)
{ … }

static const struct regmap_config ssd130x_spi_regmap_config = …;

static int ssd130x_spi_probe(struct spi_device *spi)
{ … }

static void ssd130x_spi_remove(struct spi_device *spi)
{ … }

static void ssd130x_spi_shutdown(struct spi_device *spi)
{ … }

static const struct of_device_id ssd130x_of_match[] = …;
MODULE_DEVICE_TABLE(of, ssd130x_of_match);

#if IS_MODULE(CONFIG_DRM_SSD130X_SPI)
/*
 * The SPI core always reports a MODALIAS uevent of the form "spi:<dev>", even
 * if the device was registered via OF. This means that the module will not be
 * auto loaded, unless it contains an alias that matches the MODALIAS reported.
 *
 * To workaround this issue, add a SPI device ID table. Even when this should
 * not be needed for this driver to match the registered SPI devices.
 */
static const struct spi_device_id ssd130x_spi_table[] = {
	/* ssd130x family */
	{ "sh1106",  SH1106_ID },
	{ "ssd1305", SSD1305_ID },
	{ "ssd1306", SSD1306_ID },
	{ "ssd1307", SSD1307_ID },
	{ "ssd1309", SSD1309_ID },
	/* ssd132x family */
	{ "ssd1322", SSD1322_ID },
	{ "ssd1325", SSD1325_ID },
	{ "ssd1327", SSD1327_ID },
	/* ssd133x family */
	{ "ssd1331", SSD1331_ID },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(spi, ssd130x_spi_table);
#endif

static struct spi_driver ssd130x_spi_driver = …;
module_spi_driver(…) …;

MODULE_DESCRIPTION(…);
MODULE_AUTHOR(…) …;
MODULE_LICENSE(…) …;
MODULE_IMPORT_NS(…);