These are declared in the ssd130x-i2c transport driver but the information is not I2C specific, and could be used by other SSD130x transport drivers.

Move them to the ssd130x core driver and just set the OF device entries to an ID that could be used to lookup the correct device info from an array.

While being there, also move the SSD130X_DATA and SSD130X_COMMAND control bytes. Since even though are used by the I2C interface, it could also be useful for other transport protocols such as SPI.

Suggested-by: Chen-Yu Tsai wens@kernel.org Signed-off-by: Javier Martinez Canillas javierm@redhat.com Acked-by: Mark Brown broonie@kernel.org ---

Changes in v2: - Drop ssd13x_variant_to_info() and just use the array index (Neil Armstrong).

drivers/gpu/drm/solomon/ssd130x-i2c.c | 53 +++++---------------------- drivers/gpu/drm/solomon/ssd130x.c | 45 +++++++++++++++++++++-- drivers/gpu/drm/solomon/ssd130x.h | 12 ++++++ 3 files changed, 63 insertions(+), 47 deletions(-)

diff --git a/drivers/gpu/drm/solomon/ssd130x-i2c.c b/drivers/gpu/drm/solomon/ssd130x-i2c.c index 87abe1fe31fc..8259b10db966 100644 --- a/drivers/gpu/drm/solomon/ssd130x-i2c.c +++ b/drivers/gpu/drm/solomon/ssd130x-i2c.c @@ -53,80 +53,47 @@ static void ssd130x_i2c_shutdown(struct i2c_client *client) ssd130x_shutdown(ssd130x); }

-static struct ssd130x_deviceinfo ssd130x_sh1106_deviceinfo = { - .default_vcomh = 0x40, - .default_dclk_div = 1, - .default_dclk_frq = 5, - .page_mode_only = 1, -}; - -static struct ssd130x_deviceinfo ssd130x_ssd1305_deviceinfo = { - .default_vcomh = 0x34, - .default_dclk_div = 1, - .default_dclk_frq = 7, -}; - -static struct ssd130x_deviceinfo ssd130x_ssd1306_deviceinfo = { - .default_vcomh = 0x20, - .default_dclk_div = 1, - .default_dclk_frq = 8, - .need_chargepump = 1, -}; - -static struct ssd130x_deviceinfo ssd130x_ssd1307_deviceinfo = { - .default_vcomh = 0x20, - .default_dclk_div = 2, - .default_dclk_frq = 12, - .need_pwm = 1, -}; - -static struct ssd130x_deviceinfo ssd130x_ssd1309_deviceinfo = { - .default_vcomh = 0x34, - .default_dclk_div = 1, - .default_dclk_frq = 10, -}; - static const struct of_device_id ssd130x_of_match[] = { { .compatible = "sinowealth,sh1106", - .data = &ssd130x_sh1106_deviceinfo, + .data = (void *)SH1106_ID, }, { .compatible = "solomon,ssd1305", - .data = &ssd130x_ssd1305_deviceinfo, + .data = (void *)SSD1305_ID, }, { .compatible = "solomon,ssd1306", - .data = &ssd130x_ssd1306_deviceinfo, + .data = (void *)SSD1306_ID, }, { .compatible = "solomon,ssd1307", - .data = &ssd130x_ssd1307_deviceinfo, + .data = (void *)SSD1307_ID, }, { .compatible = "solomon,ssd1309", - .data = &ssd130x_ssd1309_deviceinfo, + .data = (void *)SSD1309_ID, }, /* Deprecated but kept for backward compatibility */ { .compatible = "sinowealth,sh1106-i2c", - .data = &ssd130x_sh1106_deviceinfo, + .data = (void *)SH1106_ID, }, { .compatible = "solomon,ssd1305fb-i2c", - .data = &ssd130x_ssd1305_deviceinfo, + .data = (void *)SSD1305_ID, }, { .compatible = "solomon,ssd1306fb-i2c", - .data = &ssd130x_ssd1306_deviceinfo, + .data = (void *)SSD1306_ID, }, { .compatible = "solomon,ssd1307fb-i2c", - .data = &ssd130x_ssd1307_deviceinfo, + .data = (void *)SSD1307_ID, }, { .compatible = "solomon,ssd1309fb-i2c", - .data = &ssd130x_ssd1309_deviceinfo, + .data = (void *)SSD1309_ID, }, { /* sentinel */ } }; diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c index a7e784518c69..7d5b43023213 100644 --- a/drivers/gpu/drm/solomon/ssd130x.c +++ b/drivers/gpu/drm/solomon/ssd130x.c @@ -39,11 +39,9 @@ #define DRIVER_MAJOR 1 #define DRIVER_MINOR 0

-#define SSD130X_DATA 0x40 -#define SSD130X_COMMAND 0x80 - #define SSD130X_PAGE_COL_START_LOW 0x00 #define SSD130X_PAGE_COL_START_HIGH 0x10 + #define SSD130X_SET_ADDRESS_MODE 0x20 #define SSD130X_SET_COL_RANGE 0x21 #define SSD130X_SET_PAGE_RANGE 0x22 @@ -94,6 +92,37 @@

#define MAX_CONTRAST 255

+static const struct ssd130x_deviceinfo ssd130x_variants[] = { + [SH1106_ID] = { + .default_vcomh = 0x40, + .default_dclk_div = 1, + .default_dclk_frq = 5, + .page_mode_only = 1, + }, + [SSD1305_ID] = { + .default_vcomh = 0x34, + .default_dclk_div = 1, + .default_dclk_frq = 7, + }, + [SSD1306_ID] = { + .default_vcomh = 0x20, + .default_dclk_div = 1, + .default_dclk_frq = 8, + .need_chargepump = 1, + }, + [SSD1307_ID] = { + .default_vcomh = 0x20, + .default_dclk_div = 2, + .default_dclk_frq = 12, + .need_pwm = 1, + }, + [SSD1309_ID] = { + .default_vcomh = 0x34, + .default_dclk_div = 1, + .default_dclk_frq = 10, + } +}; + static inline struct ssd130x_device *drm_to_ssd130x(struct drm_device *drm) { return container_of(drm, struct ssd130x_device, drm); @@ -846,6 +875,7 @@ static int ssd130x_get_resources(struct ssd130x_device *ssd130x) struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap) { struct ssd130x_device *ssd130x; + enum ssd130x_variants variant; struct backlight_device *bl; struct drm_device *drm; int ret; @@ -860,7 +890,14 @@ struct ssd130x_device *ssd130x_probe(struct device *dev, struct regmap *regmap)

ssd130x->dev = dev; ssd130x->regmap = regmap; - ssd130x->device_info = device_get_match_data(dev); + + variant = (enum ssd130x_variants)device_get_match_data(dev); + + if (variant >= NR_SSD130X_VARIANTS) + return ERR_PTR(dev_err_probe(dev, -EINVAL, + "Invalid SSD130x variant\n")); + + ssd130x->device_info = &ssd130x_variants[variant];

if (ssd130x->device_info->page_mode_only) ssd130x->page_address_mode = 1; diff --git a/drivers/gpu/drm/solomon/ssd130x.h b/drivers/gpu/drm/solomon/ssd130x.h index f5b062576fdf..ec349239e945 100644 --- a/drivers/gpu/drm/solomon/ssd130x.h +++ b/drivers/gpu/drm/solomon/ssd130x.h @@ -18,6 +18,18 @@

#include <linux/regmap.h>

+#define SSD130X_DATA 0x40 +#define SSD130X_COMMAND 0x80 + +enum ssd130x_variants { + SH1106_ID, + SSD1305_ID, + SSD1306_ID, + SSD1307_ID, + SSD1309_ID, + NR_SSD130X_VARIANTS +}; + struct ssd130x_deviceinfo { u32 default_vcomh; u32 default_dclk_div;

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 ---

(no changes since v1)

drivers/gpu/drm/solomon/Kconfig | 9 ++ drivers/gpu/drm/solomon/Makefile | 1 + drivers/gpu/drm/solomon/ssd130x-spi.c | 184 ++++++++++++++++++++++++++ 3 files changed, 194 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..b6fee66a0c01 --- /dev/null +++ b/drivers/gpu/drm/solomon/ssd130x-spi.c @@ -0,0 +1,184 @@ +// 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 struct gpio_desc *ssd130x_spi_get_dc(struct device *dev) +{ + struct gpio_desc *dc = devm_gpiod_get(dev, "dc", GPIOD_OUT_LOW); + + if (IS_ERR(dc)) + return ERR_PTR(dev_err_probe(dev, PTR_ERR(dc), "Failed to get dc gpio\n")); + + return dc; +} + +static int ssd130x_spi_probe(struct spi_device *spi) +{ + struct ssd130x_spi_transport *t; + struct ssd130x_device *ssd130x; + struct regmap *regmap; + struct device *dev = &spi->dev; + + 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 = ssd130x_spi_get_dc(&spi->dev); + if (IS_ERR(t->dc)) + return PTR_ERR(t->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 = (void *)SH1106_ID, + }, + { + .compatible = "solomon,ssd1305", + .data = (void *)SSD1305_ID, + }, + { + .compatible = "solomon,ssd1306", + .data = (void *)SSD1306_ID, + }, + { + .compatible = "solomon,ssd1307", + .data = (void *)SSD1307_ID, + }, + { + .compatible = "solomon,ssd1309", + .data = (void *)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");