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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * DRM driver for Solomon SSD13xx OLED displays (SPI bus)4 *5 * Copyright 2022 Red Hat Inc.6 * Authors: Javier Martinez Canillas <javierm@redhat.com>7 */8#include <linux/spi/spi.h>9#include <linux/module.h>10 11#include "ssd130x.h"12 13#define DRIVER_NAME "ssd130x-spi"14#define DRIVER_DESC "DRM driver for Solomon SSD13xx OLED displays (SPI)"15 16struct ssd130x_spi_transport {17 struct spi_device *spi;18 struct gpio_desc *dc;19};20 21/*22 * The regmap bus .write handler, it is just a wrapper around spi_write()23 * but toggling the Data/Command control pin (D/C#). Since for 4-wire SPI24 * a D/C# pin is used, in contrast with I2C where a control byte is sent,25 * prior to every data byte, that contains a bit with the D/C# value.26 *27 * These control bytes are considered registers by the ssd130x core driver28 * and can be used by the ssd130x SPI driver to determine if the data sent29 * is for a command register or for the Graphic Display Data RAM (GDDRAM).30 */31static int ssd130x_spi_write(void *context, const void *data, size_t count)32{33 struct ssd130x_spi_transport *t = context;34 struct spi_device *spi = t->spi;35 const u8 *reg = data;36 37 if (*reg == SSD13XX_COMMAND)38 gpiod_set_value_cansleep(t->dc, 0);39 40 if (*reg == SSD13XX_DATA)41 gpiod_set_value_cansleep(t->dc, 1);42 43 /* Remove control byte since is not used in a 4-wire SPI interface */44 return spi_write(spi, reg + 1, count - 1);45}46 47/* The ssd130x driver does not read registers but regmap expects a .read */48static int ssd130x_spi_read(void *context, const void *reg, size_t reg_size,49 void *val, size_t val_size)50{51 return -EOPNOTSUPP;52}53 54static const struct regmap_config ssd130x_spi_regmap_config = {55 .reg_bits = 8,56 .val_bits = 8,57 .write = ssd130x_spi_write,58 .read = ssd130x_spi_read,59 .can_multi_write = true,60};61 62static int ssd130x_spi_probe(struct spi_device *spi)63{64 struct ssd130x_spi_transport *t;65 struct ssd130x_device *ssd130x;66 struct regmap *regmap;67 struct gpio_desc *dc;68 struct device *dev = &spi->dev;69 70 dc = devm_gpiod_get(dev, "dc", GPIOD_OUT_LOW);71 if (IS_ERR(dc))72 return dev_err_probe(dev, PTR_ERR(dc),73 "Failed to get dc gpio\n");74 75 t = devm_kzalloc(dev, sizeof(*t), GFP_KERNEL);76 if (!t)77 return dev_err_probe(dev, -ENOMEM,78 "Failed to allocate SPI transport data\n");79 80 t->spi = spi;81 t->dc = dc;82 83 regmap = devm_regmap_init(dev, NULL, t, &ssd130x_spi_regmap_config);84 if (IS_ERR(regmap))85 return PTR_ERR(regmap);86 87 ssd130x = ssd130x_probe(dev, regmap);88 if (IS_ERR(ssd130x))89 return PTR_ERR(ssd130x);90 91 spi_set_drvdata(spi, ssd130x);92 93 return 0;94}95 96static void ssd130x_spi_remove(struct spi_device *spi)97{98 struct ssd130x_device *ssd130x = spi_get_drvdata(spi);99 100 ssd130x_remove(ssd130x);101}102 103static void ssd130x_spi_shutdown(struct spi_device *spi)104{105 struct ssd130x_device *ssd130x = spi_get_drvdata(spi);106 107 ssd130x_shutdown(ssd130x);108}109 110static const struct of_device_id ssd130x_of_match[] = {111 /* ssd130x family */112 {113 .compatible = "sinowealth,sh1106",114 .data = &ssd130x_variants[SH1106_ID],115 },116 {117 .compatible = "solomon,ssd1305",118 .data = &ssd130x_variants[SSD1305_ID],119 },120 {121 .compatible = "solomon,ssd1306",122 .data = &ssd130x_variants[SSD1306_ID],123 },124 {125 .compatible = "solomon,ssd1307",126 .data = &ssd130x_variants[SSD1307_ID],127 },128 {129 .compatible = "solomon,ssd1309",130 .data = &ssd130x_variants[SSD1309_ID],131 },132 /* ssd132x family */133 {134 .compatible = "solomon,ssd1322",135 .data = &ssd130x_variants[SSD1322_ID],136 },137 {138 .compatible = "solomon,ssd1325",139 .data = &ssd130x_variants[SSD1325_ID],140 },141 {142 .compatible = "solomon,ssd1327",143 .data = &ssd130x_variants[SSD1327_ID],144 },145 /* ssd133x family */146 {147 .compatible = "solomon,ssd1331",148 .data = &ssd130x_variants[SSD1331_ID],149 },150 { /* sentinel */ }151};152MODULE_DEVICE_TABLE(of, ssd130x_of_match);153 154#if IS_MODULE(CONFIG_DRM_SSD130X_SPI)155/*156 * The SPI core always reports a MODALIAS uevent of the form "spi:<dev>", even157 * if the device was registered via OF. This means that the module will not be158 * auto loaded, unless it contains an alias that matches the MODALIAS reported.159 *160 * To workaround this issue, add a SPI device ID table. Even when this should161 * not be needed for this driver to match the registered SPI devices.162 */163static const struct spi_device_id ssd130x_spi_table[] = {164 /* ssd130x family */165 { "sh1106", SH1106_ID },166 { "ssd1305", SSD1305_ID },167 { "ssd1306", SSD1306_ID },168 { "ssd1307", SSD1307_ID },169 { "ssd1309", SSD1309_ID },170 /* ssd132x family */171 { "ssd1322", SSD1322_ID },172 { "ssd1325", SSD1325_ID },173 { "ssd1327", SSD1327_ID },174 /* ssd133x family */175 { "ssd1331", SSD1331_ID },176 { /* sentinel */ }177};178MODULE_DEVICE_TABLE(spi, ssd130x_spi_table);179#endif180 181static struct spi_driver ssd130x_spi_driver = {182 .driver = {183 .name = DRIVER_NAME,184 .of_match_table = ssd130x_of_match,185 },186 .probe = ssd130x_spi_probe,187 .remove = ssd130x_spi_remove,188 .shutdown = ssd130x_spi_shutdown,189};190module_spi_driver(ssd130x_spi_driver);191 192MODULE_DESCRIPTION(DRIVER_DESC);193MODULE_AUTHOR("Javier Martinez Canillas <javierm@redhat.com>");194MODULE_LICENSE("GPL");195MODULE_IMPORT_NS(DRM_SSD130X);196