[PATCH v3 5/7] (WIP) drm/solomon: Add SSD130X OLED displays SPI support

[Javier Martinez Canillas]

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.

Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
---

Changes in v3:
- Add a separate driver for SSD130X chips SPI support (Andy Shevchenko)

 drivers/gpu/drm/solomon/Kconfig       |   9 ++
 drivers/gpu/drm/solomon/Makefile      |   1 +
 drivers/gpu/drm/solomon/ssd130x-spi.c | 114 ++++++++++++++++++++++++++
 3 files changed, 124 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 47e16bc20e0d..16a2098f438c 100644
--- a/drivers/gpu/drm/solomon/Kconfig
+++ b/drivers/gpu/drm/solomon/Kconfig
@@ -19,3 +19,12 @@ config DRM_SSD130X_I2C
 	  Say Y here if the SSD130X OLED display is connected via 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_SPI
+	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..ccc56d2f3026
--- /dev/null
+++ b/drivers/gpu/drm/solomon/ssd130x-spi.c
@@ -0,0 +1,114 @@
+// 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@xxxxxxxxxx>
+ */
+#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)"
+
+static const struct regmap_config ssd130x_spi_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+};
+
+static int ssd130x_spi_probe(struct spi_device *spi)
+{
+	struct ssd130x_device *ssd130x;
+	struct regmap *regmap;
+
+	regmap = devm_regmap_init_spi(spi, &ssd130x_spi_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	ssd130x = ssd130x_probe(&spi->dev, regmap);
+
+	if (IS_ERR(ssd130x))
+		return PTR_ERR(ssd130x);
+
+	spi_set_drvdata(spi, ssd130x);
+
+	return 0;
+}
+
+static int ssd130x_spi_remove(struct spi_device *spi)
+{
+	struct ssd130x_device *ssd130x = spi_get_drvdata(spi);
+
+	return ssd130x_remove(ssd130x);
+}
+
+static void ssd130x_spi_shutdown(struct spi_device *spi)
+{
+	struct ssd130x_device *ssd130x = spi_get_drvdata(spi);
+
+	ssd130x_shutdown(ssd130x);
+}
+
+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 = "solomon,ssd1305fb-spi",
+		.data = (void *)&ssd130x_ssd1305_deviceinfo,
+	},
+	{
+		.compatible = "solomon,ssd1306fb-spi",
+		.data = (void *)&ssd130x_ssd1306_deviceinfo,
+	},
+	{
+		.compatible = "solomon,ssd1307fb-spi",
+		.data = (void *)&ssd130x_ssd1307_deviceinfo,
+	},
+	{
+		.compatible = "solomon,ssd1309fb-spi",
+		.data = (void *)&ssd130x_ssd1309_deviceinfo,
+	},
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, ssd130x_of_match);
+
+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@xxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");
-- 
2.34.1