The Solomon SSD130x OLED displays can either have an I2C or SPI interface, add to the schema the properties and examples for OLED devices under SPI.

Signed-off-by: Javier Martinez Canillas javierm@redhat.com Acked-by: Mark Brown broonie@kernel.org Reviewed-by: Geert Uytterhoeven geert+renesas@glider.be ---

Changes in v3: - Add a comment to the properties required for SPI (Geert Uytterhoeven)

Changes in v2: - Don't add compatible strings with an "-spi" suffix (Geert Uytterhoeven)

.../bindings/display/solomon,ssd1307fb.yaml | 38 ++++++++++++++++++- 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml index 7653b6c3fcb6..7d7de92df86f 100644 --- a/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml +++ b/Documentation/devicetree/bindings/display/solomon,ssd1307fb.yaml @@ -38,9 +38,16 @@ properties: reset-gpios: maxItems: 1

+ # Only required for SPI + dc-gpios: + maxItems: 1 + vbat-supply: description: The supply for VBAT

+ # Only required for SPI + spi-max-frequency: true + solomon,height: $ref: /schemas/types.yaml#/definitions/uint32 default: 16 @@ -220,14 +227,14 @@ examples: #address-cells = <1>; #size-cells = <0>;

- ssd1307: oled@3c { + ssd1307_i2c: oled@3c { compatible = "solomon,ssd1307"; reg = <0x3c>; pwms = <&pwm 4 3000>; reset-gpios = <&gpio2 7>; };

- ssd1306: oled@3d { + ssd1306_i2c: oled@3d { compatible = "solomon,ssd1306"; reg = <0x3c>; pwms = <&pwm 4 3000>; @@ -238,3 +245,30 @@ examples: solomon,lookup-table = /bits/ 8 <0x3f 0x3f 0x3f 0x3f>; }; }; + - | + spi { + #address-cells = <1>; + #size-cells = <0>; + + ssd1307_spi: oled@0 { + compatible = "solomon,ssd1307"; + reg = <0x0>; + pwms = <&pwm 4 3000>; + reset-gpios = <&gpio2 7>; + dc-gpios = <&gpio2 8>; + spi-max-frequency = <10000000>; + }; + + ssd1306_spi: oled@1 { + compatible = "solomon,ssd1306"; + reg = <0x1>; + pwms = <&pwm 4 3000>; + reset-gpios = <&gpio2 7>; + dc-gpios = <&gpio2 8>; + spi-max-frequency = <10000000>; + solomon,com-lrremap; + solomon,com-invdir; + solomon,com-offset = <32>; + solomon,lookup-table = /bits/ 8 <0x3f 0x3f 0x3f 0x3f>; + }; + };

The current compatible strings for SSD130x I2C controllers contain an "fb" and "-i2c" suffixes. These have been deprecated and more correct ones were added, that don't encode a subsystem or bus used to interface the devices.

Signed-off-by: Javier Martinez Canillas javierm@redhat.com Acked-by: Mark Brown broonie@kernel.org Reviewed-by: Geert Uytterhoeven geert+renesas@glider.be ---

Changes in v3: - Drop the "sinowealth,sh1106-i2c", wasn't in a released version (Chen-Yu Tsai)

Changes in v2: - Use the compatible strings that don't have "fb-i2c" (Geert Uytterhoeven).

drivers/gpu/drm/solomon/ssd130x-i2c.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/solomon/ssd130x-i2c.c b/drivers/gpu/drm/solomon/ssd130x-i2c.c index d099b241dd3f..45867ef2bc8b 100644 --- a/drivers/gpu/drm/solomon/ssd130x-i2c.c +++ b/drivers/gpu/drm/solomon/ssd130x-i2c.c @@ -88,9 +88,26 @@ static struct ssd130x_deviceinfo ssd130x_ssd1309_deviceinfo = {

static const struct of_device_id ssd130x_of_match[] = { { - .compatible = "sinowealth,sh1106-i2c", + .compatible = "sinowealth,sh1106", .data = &ssd130x_sh1106_deviceinfo, }, + { + .compatible = "solomon,ssd1305", + .data = &ssd130x_ssd1305_deviceinfo, + }, + { + .compatible = "solomon,ssd1306", + .data = &ssd130x_ssd1306_deviceinfo, + }, + { + .compatible = "solomon,ssd1307", + .data = &ssd130x_ssd1307_deviceinfo, + }, + { + .compatible = "solomon,ssd1309", + .data = &ssd130x_ssd1309_deviceinfo, + }, + /* Deprecated but kept for backward compatibility */ { .compatible = "solomon,ssd1305fb-i2c", .data = &ssd130x_ssd1305_deviceinfo,

The ssd130x driver only provides the core support for these devices but it does not have any bus transport logic. Add a driver to interface over SPI.

There is a difference in the communication protocol when using 4-wire SPI instead of I2C. For the latter, a control byte that contains a D/C# field has to be sent. This field tells the controller whether the data has to be written to the command register or to the graphics display data memory.

But for 4-wire SPI that control byte is not used, instead a real D/C# line must be pulled HIGH for commands data and LOW for graphics display data.

For this reason the standard SPI regmap can't be used and a custom .write bus handler is needed.

Signed-off-by: Javier Martinez Canillas javierm@redhat.com Acked-by: Mark Brown broonie@kernel.org ---

Changes in v3: - Drop ssd130x_spi_get_dc() helper and open code it (Geert Uytterhoeven) - Export variants array and use &info[ID] in device table (Andy Shevchenko)

Changes in v2: - Add the same compatible strings than I2C (Geert Uytterhoeven)

drivers/gpu/drm/solomon/Kconfig | 9 ++ drivers/gpu/drm/solomon/Makefile | 1 + drivers/gpu/drm/solomon/ssd130x-spi.c | 177 ++++++++++++++++++++++++++ 3 files changed, 187 insertions(+) create mode 100644 drivers/gpu/drm/solomon/ssd130x-spi.c

diff --git a/drivers/gpu/drm/solomon/Kconfig b/drivers/gpu/drm/solomon/Kconfig index 8c0a0c788385..e170716d976b 100644 --- a/drivers/gpu/drm/solomon/Kconfig +++ b/drivers/gpu/drm/solomon/Kconfig @@ -20,3 +20,12 @@ config DRM_SSD130X_I2C I2C bus.

If M is selected the module will be called ssd130x-i2c. + +config DRM_SSD130X_SPI + tristate "DRM support for Solomon SSD130X OLED displays (SPI bus)" + depends on DRM_SSD130X && SPI + select REGMAP + help + Say Y here if the SSD130x OLED display is connected via SPI bus. + + If M is selected the module will be called ssd130x-spi. diff --git a/drivers/gpu/drm/solomon/Makefile b/drivers/gpu/drm/solomon/Makefile index 4bfc5acb0447..b5fc792257d7 100644 --- a/drivers/gpu/drm/solomon/Makefile +++ b/drivers/gpu/drm/solomon/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_DRM_SSD130X) += ssd130x.o obj-$(CONFIG_DRM_SSD130X_I2C) += ssd130x-i2c.o +obj-$(CONFIG_DRM_SSD130X_SPI) += ssd130x-spi.o diff --git a/drivers/gpu/drm/solomon/ssd130x-spi.c b/drivers/gpu/drm/solomon/ssd130x-spi.c new file mode 100644 index 000000000000..4fda420ae0a6 --- /dev/null +++ b/drivers/gpu/drm/solomon/ssd130x-spi.c @@ -0,0 +1,177 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * DRM driver for Solomon SSD130X OLED displays (SPI bus) + * + * Copyright 2022 Red Hat Inc. + * Authors: Javier Martinez Canillas javierm@redhat.com + */ +#include <linux/spi/spi.h> +#include <linux/module.h> + +#include "ssd130x.h" + +#define DRIVER_NAME "ssd130x-spi" +#define DRIVER_DESC "DRM driver for Solomon SSD130X OLED displays (SPI)" + +struct ssd130x_spi_transport { + struct spi_device *spi; + struct gpio_desc *dc; +}; + +static const struct regmap_config ssd130x_spi_regmap_config = { + .reg_bits = 8, + .val_bits = 8, +}; + +/* + * 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) +{ + struct ssd130x_spi_transport *t = context; + struct spi_device *spi = t->spi; + const u8 *reg = data; + + if (*reg == SSD130X_COMMAND) + gpiod_set_value_cansleep(t->dc, 0); + + if (*reg == SSD130X_DATA) + gpiod_set_value_cansleep(t->dc, 1); + + /* Remove the control byte since is not used by the 4-wire SPI */ + return spi_write(spi, ((u8 *)data) + 1, count - 1); +} + +/* 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) +{ + return -EOPNOTSUPP; +} + +/* + * A custom bus is needed due the special write that toggles a D/C# pin, + * another option could be to just have a .reg_write() callback but that + * will prevent to do data writes in bulk. + * + * Once the regmap API is extended to support defining a bulk write handler + * in the struct regmap_config, this can be simplified and the bus dropped. + */ +static struct regmap_bus regmap_ssd130x_spi_bus = { + .write = ssd130x_spi_write, + .read = ssd130x_spi_read, +}; + +static int ssd130x_spi_probe(struct spi_device *spi) +{ + struct ssd130x_spi_transport *t; + struct ssd130x_device *ssd130x; + struct regmap *regmap; + struct gpio_desc *dc; + struct device *dev = &spi->dev; + + dc = devm_gpiod_get(dev, "dc", GPIOD_OUT_LOW); + if (IS_ERR(dc)) + return dev_err_probe(dev, PTR_ERR(dc), + "Failed to get dc gpio\n"); + + t = devm_kzalloc(dev, sizeof(*t), GFP_KERNEL); + if (!t) + return dev_err_probe(dev, -ENOMEM, + "Failed to allocate SPI transport data\n"); + + t->spi = spi; + t->dc = dc; + + regmap = devm_regmap_init(dev, &regmap_ssd130x_spi_bus, t, + &ssd130x_spi_regmap_config); + if (IS_ERR(regmap)) + return PTR_ERR(regmap); + + ssd130x = ssd130x_probe(dev, regmap); + if (IS_ERR(ssd130x)) + return PTR_ERR(ssd130x); + + spi_set_drvdata(spi, ssd130x); + + return 0; +} + +static void ssd130x_spi_remove(struct spi_device *spi) +{ + struct ssd130x_device *ssd130x = spi_get_drvdata(spi); + + ssd130x_remove(ssd130x); +} + +static void ssd130x_spi_shutdown(struct spi_device *spi) +{ + struct ssd130x_device *ssd130x = spi_get_drvdata(spi); + + ssd130x_shutdown(ssd130x); +} + +static const struct of_device_id ssd130x_of_match[] = { + { + .compatible = "sinowealth,sh1106", + .data = &ssd130x_variants[SH1106_ID], + }, + { + .compatible = "solomon,ssd1305", + .data = &ssd130x_variants[SSD1305_ID], + }, + { + .compatible = "solomon,ssd1306", + .data = &ssd130x_variants[SSD1306_ID], + }, + { + .compatible = "solomon,ssd1307", + .data = &ssd130x_variants[SSD1307_ID], + }, + { + .compatible = "solomon,ssd1309", + .data = &ssd130x_variants[SSD1309_ID], + }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, ssd130x_of_match); + +/* + * 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[] = { + { "sh1106", SH1106_ID }, + { "ssd1305", SSD1305_ID }, + { "ssd1306", SSD1306_ID }, + { "ssd1307", SSD1307_ID }, + { "ssd1309", SSD1309_ID }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(spi, ssd130x_spi_table); + +static struct spi_driver ssd130x_spi_driver = { + .driver = { + .name = DRIVER_NAME, + .of_match_table = ssd130x_of_match, + }, + .probe = ssd130x_spi_probe, + .remove = ssd130x_spi_remove, + .shutdown = ssd130x_spi_shutdown, +}; +module_spi_driver(ssd130x_spi_driver); + +MODULE_DESCRIPTION(DRIVER_DESC); +MODULE_AUTHOR("Javier Martinez Canillas javierm@redhat.com"); +MODULE_LICENSE("GPL");