On 02/24/2017 03:25 PM, Bastian Stender wrote:
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 <b...@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

Oops, it actually does not depend on PWM. Only the SSD1307 needs PWM, but I did not port that part as I have no way to test it. I should probably mention that.

+
 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)

Remove that for now.

+ *     - SSD1309 (untested)
+ *
+ * Copyright 2012 Maxime Ripard <maxime.rip...@free-electrons.com>, Free 
Electrons
+ *
+ * Ported to barebox from linux v4.10
+ * Copyright (C) 2017 Pengutronix, Bastian Stender <ker...@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,
+};

Remove this too.

+
+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,
+       },

Remove this too.

+       {
+               .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);


If anybody is confident enough to port the pwm parts or can actually test this, we can add SSD1307 compatability again.

I will send a reworked version of this patch, but for now I'll wait for some more review.

Regards,
Bastian

--
Pengutronix e.K.
Industrial Linux Solutions
http://www.pengutronix.de/
Peiner Str. 6-8, 31137 Hildesheim, Germany
Amtsgericht Hildesheim, HRA 2686

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