[PATCH 4/4] video: add support for Solomon SSD1307 OLED controller family

[Bastian Stender <bst@pengutronix.de>]

It was ported from linux v4.10. Like the kernel driver only
communication via I2C is supported.

It has only been tested with a SSD1306 and a 96x16 OLED display:

	&i2c0 {
		status = "okay";

		ssd1306: oled@3c {
			compatible = "solomon,ssd1306fb-i2c";
			reg = <0x3c>;
			reset-gpios = <&gpio1 1 0>;
			solomon,height = <16>;
			solomon,width = <96>;
			solomon,page-offset = <0>;
			solomon,com-invdir;
			solomon,com-seq;
		};

Signed-off-by: Bastian Stender <bst@pengutronix.de>
---
 drivers/video/Kconfig     |   4 +
 drivers/video/Makefile    |   1 +
 drivers/video/ssd1307fb.c | 569 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 574 insertions(+)
 create mode 100644 drivers/video/ssd1307fb.c

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 8f31f5af74..50a876acb1 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -12,6 +12,10 @@ config FRAMEBUFFER_CONSOLE
 	select FONTS
 	prompt "framebuffer console support"
 
+config DRIVER_VIDEO_FB_SSD1307
+	bool "Solomon SSD1307 framebuffer support"
+	depends on PWM && I2C && GPIOLIB
+
 config VIDEO_VPL
 	depends on OFTREE
 	bool
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 1bf2e1f3ca..e23c9c37b6 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -21,3 +21,4 @@ obj-$(CONFIG_DRIVER_VIDEO_OMAP) += omap.o
 obj-$(CONFIG_DRIVER_VIDEO_BCM283X) += bcm2835.o
 obj-$(CONFIG_DRIVER_VIDEO_SIMPLEFB) += simplefb.o
 obj-$(CONFIG_DRIVER_VIDEO_IMX_IPUV3) += imx-ipu-v3/
+obj-$(CONFIG_DRIVER_VIDEO_FB_SSD1307) += ssd1307fb.o
diff --git a/drivers/video/ssd1307fb.c b/drivers/video/ssd1307fb.c
new file mode 100644
index 0000000000..0dfdcc2232
--- /dev/null
+++ b/drivers/video/ssd1307fb.c
@@ -0,0 +1,569 @@
+/*
+ * Driver for the Solomon SSD1307 OLED controller family
+ *
+ * Supports:
+ *	- SSD1305 (untested)
+ *	- SSD1306
+ *	- SSD1307 (untested)
+ *	- SSD1309 (untested)
+ *
+ * Copyright 2012 Maxime Ripard <maxime.ripard@free-electrons.com>, Free Electrons
+ *
+ * Ported to barebox from linux v4.10
+ * Copyright (C) 2017 Pengutronix, Bastian Stender <kernel@pengutronix.de>
+ *
+ * Licensed under the GPLv2 or later.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <fb.h>
+#include <i2c/i2c.h>
+#include <of_device.h>
+#include <gpio.h>
+#include <of_gpio.h>
+#include <printk.h>
+
+#define SSD1307FB_DATA			0x40
+#define SSD1307FB_COMMAND		0x80
+
+#define SSD1307FB_SET_ADDRESS_MODE	0x20
+#define SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL	(0x00)
+#define SSD1307FB_SET_ADDRESS_MODE_VERTICAL	(0x01)
+#define SSD1307FB_SET_ADDRESS_MODE_PAGE		(0x02)
+#define SSD1307FB_SET_COL_RANGE		0x21
+#define SSD1307FB_SET_PAGE_RANGE	0x22
+#define SSD1307FB_CONTRAST		0x81
+#define	SSD1307FB_CHARGE_PUMP		0x8d
+#define SSD1307FB_SEG_REMAP_ON		0xa1
+#define SSD1307FB_DISPLAY_OFF		0xae
+#define SSD1307FB_SET_MULTIPLEX_RATIO	0xa8
+#define SSD1307FB_DISPLAY_ON		0xaf
+#define SSD1307FB_START_PAGE_ADDRESS	0xb0
+#define SSD1307FB_SET_DISPLAY_OFFSET	0xd3
+#define	SSD1307FB_SET_CLOCK_FREQ	0xd5
+#define	SSD1307FB_SET_PRECHARGE_PERIOD	0xd9
+#define	SSD1307FB_SET_COM_PINS_CONFIG	0xda
+#define	SSD1307FB_SET_VCOMH		0xdb
+
+struct ssd1307fb_par;
+
+struct ssd1307fb_deviceinfo {
+	u32 default_vcomh;
+	u32 default_dclk_div;
+	u32 default_dclk_frq;
+	int need_chargepump;
+};
+
+struct ssd1307fb_par {
+	u32 com_invdir;
+	u32 com_lrremap;
+	u32 com_offset;
+	u32 com_seq;
+	u32 contrast;
+	u32 dclk_div;
+	u32 dclk_frq;
+	const struct ssd1307fb_deviceinfo *device_info;
+	struct i2c_client *client;
+	u32 height;
+	struct fb_info *info;
+	u32 page_offset;
+	u32 prechargep1;
+	u32 prechargep2;
+	int reset;
+	u32 seg_remap;
+	u32 vcomh;
+	u32 width;
+};
+
+struct ssd1307fb_array {
+	u8	type;
+	u8	data[0];
+};
+
+static struct ssd1307fb_array *ssd1307fb_alloc_array(u32 len, u8 type)
+{
+	struct ssd1307fb_array *array;
+
+	array = kzalloc(sizeof(struct ssd1307fb_array) + len, GFP_KERNEL);
+	if (!array)
+		return NULL;
+
+	array->type = type;
+
+	return array;
+}
+
+static int ssd1307fb_write_array(struct i2c_client *client,
+				 struct ssd1307fb_array *array, u32 len)
+{
+	int ret;
+
+	len += sizeof(struct ssd1307fb_array);
+
+	ret = i2c_master_send(client, (u8 *)array, len);
+	if (ret != len) {
+		dev_err(&client->dev, "Couldn't send I2C command.\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
+{
+	struct ssd1307fb_array *array;
+	int ret;
+
+	array = ssd1307fb_alloc_array(1, SSD1307FB_COMMAND);
+	if (!array)
+		return -ENOMEM;
+
+	array->data[0] = cmd;
+
+	ret = ssd1307fb_write_array(client, array, 1);
+	kfree(array);
+
+	return ret;
+}
+
+static void ssd1307fb_update_display(struct ssd1307fb_par *par)
+{
+	struct ssd1307fb_array *array;
+	u8 *vmem = par->info->screen_base;
+	int i, j, k;
+
+	array = ssd1307fb_alloc_array(par->width * par->height / 8,
+				      SSD1307FB_DATA);
+	if (!array)
+		return;
+
+	/*
+	 * The screen is divided in pages, each having a height of 8
+	 * pixels, and the width of the screen. When sending a byte of
+	 * data to the controller, it gives the 8 bits for the current
+	 * column. I.e, the first byte are the 8 bits of the first
+	 * column, then the 8 bits for the second column, etc.
+	 *
+	 *
+	 * Representation of the screen, assuming it is 5 bits
+	 * wide. Each letter-number combination is a bit that controls
+	 * one pixel.
+	 *
+	 * A0 A1 A2 A3 A4
+	 * B0 B1 B2 B3 B4
+	 * C0 C1 C2 C3 C4
+	 * D0 D1 D2 D3 D4
+	 * E0 E1 E2 E3 E4
+	 * F0 F1 F2 F3 F4
+	 * G0 G1 G2 G3 G4
+	 * H0 H1 H2 H3 H4
+	 *
+	 * If you want to update this screen, you need to send 5 bytes:
+	 *  (1) A0 B0 C0 D0 E0 F0 G0 H0
+	 *  (2) A1 B1 C1 D1 E1 F1 G1 H1
+	 *  (3) A2 B2 C2 D2 E2 F2 G2 H2
+	 *  (4) A3 B3 C3 D3 E3 F3 G3 H3
+	 *  (5) A4 B4 C4 D4 E4 F4 G4 H4
+	 */
+
+	for (i = 0; i < (par->height / 8); i++) {
+		for (j = 0; j < par->width; j++) {
+			u32 array_idx = i * par->width + j;
+			array->data[array_idx] = 0;
+			for (k = 0; k < 8; k++) {
+				u32 page_length = par->width * i * 8;
+				u32 index = page_length + (par->width * k + j);
+				u8 byte = *(vmem + index);
+				/* convert to 1 bit per pixel */
+				u8 bit = byte > 0;
+				array->data[array_idx] |= bit << k;
+			}
+		}
+	}
+
+	ssd1307fb_write_array(par->client, array, par->width * par->height / 8);
+	kfree(array);
+}
+
+static void ssd1307fb_enable(struct fb_info *info)
+{
+	struct ssd1307fb_par *par = info->priv;
+	ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
+}
+
+static void ssd1307fb_disable(struct fb_info *info)
+{
+	struct ssd1307fb_par *par = info->priv;
+	ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_OFF);
+}
+
+static void ssd1307fb_flush(struct fb_info *info)
+{
+	struct ssd1307fb_par *par = info->priv;
+	ssd1307fb_update_display(par);
+}
+
+static struct fb_ops ssd1307fb_ops = {
+	.fb_enable	= ssd1307fb_enable,
+	.fb_disable	= ssd1307fb_disable,
+	.fb_flush	= ssd1307fb_flush,
+};
+
+static int ssd1307fb_init(struct ssd1307fb_par *par)
+{
+	int ret;
+	u32 precharge, dclk, com_invdir, compins;
+
+	/* Set initial contrast */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CONTRAST);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, par->contrast);
+	if (ret < 0)
+		return ret;
+
+	/* Set segment re-map */
+	if (par->seg_remap) {
+		ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SEG_REMAP_ON);
+		if (ret < 0)
+			return ret;
+	};
+
+	/* Set COM direction */
+	com_invdir = 0xc0 | (par->com_invdir & 0x1) << 3;
+	ret = ssd1307fb_write_cmd(par->client,  com_invdir);
+	if (ret < 0)
+		return ret;
+
+	/* Set multiplex ratio value */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_MULTIPLEX_RATIO);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, par->height - 1);
+	if (ret < 0)
+		return ret;
+
+	/* set display offset value */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_DISPLAY_OFFSET);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, par->com_offset);
+	if (ret < 0)
+		return ret;
+
+	/* Set clock frequency */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_CLOCK_FREQ);
+	if (ret < 0)
+		return ret;
+
+	dclk = ((par->dclk_div - 1) & 0xf) | (par->dclk_frq & 0xf) << 4;
+	ret = ssd1307fb_write_cmd(par->client, dclk);
+	if (ret < 0)
+		return ret;
+
+	/* Set precharge period in number of ticks from the internal clock */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PRECHARGE_PERIOD);
+	if (ret < 0)
+		return ret;
+
+	precharge = (par->prechargep1 & 0xf) | (par->prechargep2 & 0xf) << 4;
+	ret = ssd1307fb_write_cmd(par->client, precharge);
+	if (ret < 0)
+		return ret;
+
+	/* Set COM pins configuration */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COM_PINS_CONFIG);
+	if (ret < 0)
+		return ret;
+
+	compins = 0x02 | !(par->com_seq & 0x1) << 4
+				   | (par->com_lrremap & 0x1) << 5;
+	ret = ssd1307fb_write_cmd(par->client, compins);
+	if (ret < 0)
+		return ret;
+
+	/* Set VCOMH */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_VCOMH);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, par->vcomh);
+	if (ret < 0)
+		return ret;
+
+	/* Turn on the DC-DC Charge Pump */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_CHARGE_PUMP);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client,
+		BIT(4) | (par->device_info->need_chargepump ? BIT(2) : 0));
+	if (ret < 0)
+		return ret;
+
+	/* Switch to horizontal addressing mode */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_ADDRESS_MODE);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client,
+				  SSD1307FB_SET_ADDRESS_MODE_HORIZONTAL);
+	if (ret < 0)
+		return ret;
+
+	/* Set column range */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, par->width - 1);
+	if (ret < 0)
+		return ret;
+
+	/* Set page range */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, 0x0);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client,
+				  par->page_offset + (par->height / 8) - 1);
+	if (ret < 0)
+		return ret;
+
+	/* Turn on the display */
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_DISPLAY_ON);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static struct ssd1307fb_deviceinfo ssd1307fb_ssd1305_deviceinfo = {
+	.default_vcomh = 0x34,
+	.default_dclk_div = 1,
+	.default_dclk_frq = 7,
+};
+
+static struct ssd1307fb_deviceinfo ssd1307fb_ssd1306_deviceinfo = {
+	.default_vcomh = 0x20,
+	.default_dclk_div = 1,
+	.default_dclk_frq = 8,
+	.need_chargepump = 1,
+};
+
+static struct ssd1307fb_deviceinfo ssd1307fb_ssd1307_deviceinfo = {
+	.default_vcomh = 0x20,
+	.default_dclk_div = 2,
+	.default_dclk_frq = 12,
+};
+
+static struct ssd1307fb_deviceinfo ssd1307fb_ssd1309_deviceinfo = {
+	.default_vcomh = 0x34,
+	.default_dclk_div = 1,
+	.default_dclk_frq = 10,
+};
+
+static const struct of_device_id ssd1307fb_of_match[] = {
+	{
+		.compatible = "solomon,ssd1305fb-i2c",
+		.data = (void *)&ssd1307fb_ssd1305_deviceinfo,
+	},
+	{
+		.compatible = "solomon,ssd1306fb-i2c",
+		.data = (void *)&ssd1307fb_ssd1306_deviceinfo,
+	},
+	{
+		.compatible = "solomon,ssd1307fb-i2c",
+		.data = (void *)&ssd1307fb_ssd1307_deviceinfo,
+	},
+	{
+		.compatible = "solomon,ssd1309fb-i2c",
+		.data = (void *)&ssd1307fb_ssd1309_deviceinfo,
+	},
+	{},
+};
+
+static int ssd1307fb_probe(struct device_d *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct fb_info *info;
+	struct device_node *node = dev->device_node;
+	const struct of_device_id *match =
+		of_match_node(ssd1307fb_of_match, dev->device_node);
+	u32 vmem_size;
+	struct ssd1307fb_par *par;
+	struct ssd1307fb_array *array;
+	u8 *vmem;
+	int ret;
+	int i, j;
+
+	if (!node) {
+		dev_err(&client->dev, "No device tree data found!\n");
+		return -EINVAL;
+	}
+
+	info = xzalloc(sizeof(struct fb_info));
+	if (!info) {
+		dev_err(&client->dev, "Couldn't allocate framebuffer.\n");
+		return -ENOMEM;
+	}
+
+	par = info->priv;
+	par->info = info;
+	par->client = client;
+
+	par->device_info = (struct ssd1307fb_deviceinfo *)match->data;
+
+	par->reset = of_get_named_gpio(node,
+					 "reset-gpios", 0);
+	if (!gpio_is_valid(par->reset)) {
+		dev_err(&client->dev,
+			"Couldn't get named gpio 'reset-gpios' %d.\n",
+			par->reset);
+		ret = par->reset;
+		goto fb_alloc_error;
+	}
+
+	if (of_property_read_u32(node, "solomon,width", &par->width))
+		par->width = 96;
+
+	if (of_property_read_u32(node, "solomon,height", &par->height))
+		par->height = 16;
+
+	if (of_property_read_u32(node, "solomon,page-offset",
+				 &par->page_offset))
+		par->page_offset = 1;
+
+	if (of_property_read_u32(node, "solomon,com-offset", &par->com_offset))
+		par->com_offset = 0;
+
+	if (of_property_read_u32(node, "solomon,prechargep1",
+				 &par->prechargep1))
+		par->prechargep1 = 2;
+
+	if (of_property_read_u32(node, "solomon,prechargep2",
+				 &par->prechargep2))
+		par->prechargep2 = 2;
+
+	par->seg_remap = !of_property_read_bool(node,
+						"solomon,segment-no-remap");
+	par->com_seq = of_property_read_bool(node, "solomon,com-seq");
+	par->com_lrremap = of_property_read_bool(node, "solomon,com-lrremap");
+	par->com_invdir = of_property_read_bool(node, "solomon,com-invdir");
+
+	par->contrast = 127;
+	par->vcomh = par->device_info->default_vcomh;
+
+	/* Setup display timing */
+	par->dclk_div = par->device_info->default_dclk_div;
+	par->dclk_frq = par->device_info->default_dclk_frq;
+
+	vmem_size = par->width * par->height;
+
+	vmem = malloc(vmem_size);
+	if (!vmem) {
+		dev_err(&client->dev, "Couldn't allocate graphical memory.\n");
+		ret = -ENOMEM;
+		goto fb_alloc_error;
+	}
+
+	info->fbops = &ssd1307fb_ops;
+	info->line_length = par->width;
+
+	info->xres = par->width;
+	info->yres = par->height;
+
+	/* emulate 8 bit per pixel */
+	info->bits_per_pixel = 8;
+
+	info->red.length = 3;
+	info->red.offset = 0;
+	info->green.length = 3;
+	info->green.offset = 0;
+	info->blue.length = 2;
+	info->blue.offset = 0;
+
+	info->screen_base = (u8 __force __iomem *)vmem;
+
+	ret = gpio_request_one(par->reset,
+			       GPIOF_OUT_INIT_HIGH,
+			       "oled-reset");
+	if (ret) {
+		dev_err(&client->dev,
+			"failed to request gpio %d: %d\n",
+			par->reset, ret);
+		goto reset_oled_error;
+	}
+
+	i2c_set_clientdata(client, info);
+
+	/* Reset the screen */
+	gpio_set_value(par->reset, 0);
+	udelay(4);
+	gpio_set_value(par->reset, 1);
+	udelay(4);
+
+	ret = ssd1307fb_init(par);
+	if (ret)
+		goto reset_oled_error;
+
+	ret = register_framebuffer(info);
+	if (ret) {
+		dev_err(&client->dev, "Couldn't register the framebuffer\n");
+		goto panel_init_error;
+	}
+
+	/* clear display */
+	array = ssd1307fb_alloc_array(par->width * par->height / 8,
+				      SSD1307FB_DATA);
+	if (!array)
+		return -ENOMEM;
+
+	for (i = 0; i < (par->height / 8); i++) {
+		for (j = 0; j < par->width; j++) {
+			u32 array_idx = i * par->width + j;
+			array->data[array_idx] = 0;
+		}
+	}
+
+	ssd1307fb_write_array(par->client, array, par->width * par->height / 8);
+	kfree(array);
+
+	dev_info(&client->dev,
+		 "ssd1307 framebuffer device registered, using %d bytes of video memory\n",
+		 vmem_size);
+
+	return 0;
+
+panel_init_error:
+reset_oled_error:
+fb_alloc_error:
+	free(info);
+	return ret;
+}
+
+static struct driver_d ssd1307fb_driver = {
+	.name = "ssd1307fb",
+	.probe = ssd1307fb_probe,
+	.of_compatible = DRV_OF_COMPAT(ssd1307fb_of_match),
+};
+
+static int ssd1307_init(void)
+{
+	i2c_driver_register(&ssd1307fb_driver);
+	return 0;
+}
+
+device_initcall(ssd1307_init);
-- 
2.11.0


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